Articoli di riviste: "Schiff base ligands"

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Biswas, Arpita. "A Brief Review on Homo-/Hetero-nuclear Co-ordination Compounds Derived from Some Single Compartmentl Acyclic Schiff Base Ligands having N-,O-Donor Centres". Oriental Journal Of Chemistry 38, n. 4 (31 agosto 2022): 957–66. http://dx.doi.org/10.13005/ojc/380417.

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Tetradentate acyclic compartmental Schiff base ligand with N2O2 compartment afford suitable coordination environment for large variety of metal ions. This type of ligands can easily be synthesized by [2+1] condensation of a carbonyl compounds with a diamine. Several metal complexes have been reported from the single- and double-compartment acyclic Schiff base ligands which are the [2+1] condensation products of salicylaldehyde, 2-hydroxyacetophenone, 3-methoxysalicylaldehyde, 3-ethoxysalicylaldehyde and a diamine; The diamine counterpart in these ligands are ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1-methylethylenediamine, 2,2-dimethyl,1,3-diaminopropane, o-phenylenediamine, trans-1,2-diaminocyclohexane, etc. Several review article has been published previously on compartmental Schiff base ligand compounds. This review article focused only the type and structures of Cu(II)/Ni(II)-second metal (s-, p-, d10-, 3d-,, 4f- block metal) homo-/hetero- nuclear coordination comppounds derived from single compartmentl salicyaldehyde-diamine and acetophenone-diamine ligand systems.

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Odularu, Ayodele Temidayo. "Manganese Schiff Base Complexes, Crystallographic Studies, Anticancer Activities, and Molecular Docking". Journal of Chemistry 2022 (24 agosto 2022): 1–19. http://dx.doi.org/10.1155/2022/7062912.

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Choice of ligands is significant to successful synthesis of metal complexes (coordination compounds). This study reports the use of Schiff base as the right ligand to control the poor bioavailability and neurodegenerative toxicity challenges of manganese ion. In line with this study, document analysis was used as the methodological approach to evaluate the significance of Schiff base ligands in easing these manganese’s challenges and aligning the resultant coordination compounds (manganese Schiff base complexes) as therapeutic agents in anticancer studies. Report also involves crystallographic studies where single crystal X-ray crystallography was used as a chemical characterization technique. In addition, molecular docking studies, MOE2008, and AutoDock software were used to reveal the mode of interaction between the Schiff base and the manganese(II) and (III) ions, as well as scrutinizing the biological efficacy of the manganese(II) and manganese(III) Schiff bases coordination compounds as anticancer agents against some anticancer cell lines. Conclusion drawn was that manganese(II) and manganese(III) Schiff bases coordination compounds gave more active and potent activities than the corresponding Schiff bases. As a result, challenges of neurodegenerative toxicity and poor bioavailability of manganese ion were overcome, and the chelation therapy was fulfilled. Results from single crystal X-ray crystallography confirmed the successful synthesis of manganese(II) and manganese(III) Schiff bases coordination compounds and revealed the mechanism of reaction, while the molecular docking buttressed the biological activities of the Schiff base ligand and manganese Schiff base coordination compounds by portraying the structure activity relationship (SAR) between either Schiff base or the manganese Schiff base coordination compounds and the virtual cancer cell line (receptor protein), where hits were obtained for lead optimizations.

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Ayuba, Isiyaku, Tajo Siraj Ibrahim, Umar Maigari Aishatu e Magaji Buhari. "Synthesis, characterization and anti-bacterial activity of Schiff Base and its mixed ligand complexes of Cr (II) and Co (II) containing vanillin and 2-aminophenol". Dutse Journal of Pure and Applied Sciences 7, n. 4a (2 febbraio 2022): 98–104. http://dx.doi.org/10.4314/dujopas.v7i4a.11.

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Schiff Base are organic ligand that contained azomethine linkage (-HC=N-) which shows biological importance. Schiff Base from vanillin and 2-aminophenol was synthesized in 1:1 mole ratio. The complexes of Cr (II) and Co (II) from Schiff Base in 1:2 mole ratio metal-ligand (M-L) and the mixed ligand complexes from Schiff Base and 2-aminophenol in 1:1:1 mole ratio ligand-metal-ligand(L-M-L) were synthesized and characterized based on solubility, melting point, conductivity, Fourier transform infrared spectroscopy (FTIR) and ultraviolet (UV). The solubility result shows that, dimethyl sulfoxide(DMSO) dissolved all the complexes. The results obtained from melting point, conductivity indicated purity and non-electrolytic of the complexes respectively. In metal complexes, the infrared data showed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group and oxygen in phenolic group. In mixed ligand complexes, the infrared data revealed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group, oxygen in phenolic group and nitrogen in amino group. The results showed a six coordinate octahedral geometry for these complexes. The ligands and the metal complexes were examined for their antibacterial activity using agar well diffusion method against Escherichia coli, Staphylococcus aureus, streptococcus pyrogens , Klebsiella pneumonia (gram - bacteria), and Bacillus sutilis, Staphylococcus aureus (gram + bacteria). In comparing the results, the complex of Co(HL1)2 has greater zone of inhibition against the tested organism than the free ligands as antibacterial agent.

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Sharma, Bharat Prasad, Sarvesh Kumar Pandey, Bishnu Prasad Marasini, Sabita Shrestha e Motee Lal Sharma. "Oxovanadium(IV) Complexes with Triazole Based Schiff Base Ligands: Synthesis, Characterization and Antibacterial Study". Journal of Nepal Chemical Society 42, n. 1 (1 marzo 2021): 56–63. http://dx.doi.org/10.3126/jncs.v42i1.35332.

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Schiff bases have been synthesized by the reaction of triazole containing primary amine with aromatic carbonyl compounds. The Schiff bases prepared, act as ligand when these are made in contact with oxovanadium (VO2+) ion. Some new mononuclear oxovanadium(IV) complexes have been synthesized by the reaction of Schiff base ligands with vanadyl sulphate (VOSO4.xH2O) and the complexes are analyzed by different spectroscopic methods; [fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis.), electron paramagnetic resonance (EPR)], X-ray diffraction (XRD) analysis, elemental analysis, and conductivity measurement. The complexes have been well characterized based on analytical data. The electrolytic nature of the complexes was determined based on the molar conductance values. The powder XRD pattern has been used to determine crystal size and type. The synthesized Schiff base ligands and oxovanadium(IV) complexes were found to be stable in air and moisture at room temperature. On the basis of the physicochemical data, the tentative geometry of the complexes has been proposed. Antibacterial sensitivity of the ligand and its metal complexes have been assayed in vitro against bacterial pathogens viz. growth inhibitory activity of ligands and complexes against pathogens has also been determined.

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Hsu, Chiao-Yin, Hsi-Ching Tseng, Jaya Kishore Vandavasi, Wei-Yi Lu, Li-Fang Wang, Michael Y. Chiang, Yi-Chun Lai, Hsing-Yin Chen e Hsuan-Ying Chen. "Investigation of the dinuclear effect of aluminum complexes in the ring-opening polymerization of ε-caprolactone". RSC Advances 7, n. 31 (2017): 18851–60. http://dx.doi.org/10.1039/c7ra02136d.

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Al complexes bearing hydrazine-bridging Schiff base ligands showed the best catalytic activity, approximately 3- to 11-fold higher than that of dinuclear Al complexes bearing Salen ligands and mononuclear Al complexes bearing Schiff base ligands.

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Soroceanu, Alina, e Alexandra Bargan. "Advanced and Biomedical Applications of Schiff-Base Ligands and Their Metal Complexes: A Review". Crystals 12, n. 10 (12 ottobre 2022): 1436. http://dx.doi.org/10.3390/cryst12101436.

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Because of their importance in a variety of interdisciplinary study domains, Schiff-base ligands have performed a significant role in the evolution of contemporary coordination chemistry. This almost-comprehensive review covers all the aspects and properties of complexes, starting from the Schiff-base ligands. Our work is centered on the eloquent advances that have been developed since 2015, with special consideration to recent developments. Schiff-base ligands and their complexes are adaptable compounds obtained from the condensation of two compounds: a carbonyl with an amino. The correspondent metal complexes have been shown to have antifungal, antibacterial, antioxidant, antiproliferative, and antiviral properties. This review begins with a short introduction to Schiff-base ligands and their metal complexes. It stands out in the recent advancements in the Schiff-base coordination chemistry domain and its future prospects as a potential bioactive core. Additionally, the review contains knowledge about the antioxidant, redox, and catalytic activities of the Schiff-base complexes, with important future applications in the obtaining of new compounds and materials.

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Jurowska, Anna, Janusz Szklarzewicz, Maciej Hodorowicz, Wiktoria Serafin, Ennio Zangrando e Ghodrat Mahmoudi. "Ionic Dioxidovanadium(V) Complexes with Schiff-Base Ligands as Potential Insulin-Mimetic Agents—Substituent Effect on Structure and Stability". Molecules 27, n. 20 (16 ottobre 2022): 6942. http://dx.doi.org/10.3390/molecules27206942.

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Four dioxidovanadium(V) complexes with Schiff-base ligands based on 2-hydroxybenzhydrazide with four different substituted salicylaldehydes (5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde, 5-nitrosalicylaldehyde, 3-bromo-5-chlorosalicylaldehyde) were synthesized and described, by using V2O5 and triethylamine. The single crystal X-ray structure measurements as well as elemental analyses and IR spectra confirmed the formulas of the ionic complexes with a protonated triethylamine acting as counterion, HTEA[VO2(L)] (HL = Schiff-base ligand). The kinetic stability of the complexes at pH = 2 and 7 was discussed with respect to the neutral vanadium(V) complexes previously studied as potential insulin-mimetic agents. A correlation between the substituents in an aromatic ring of the Schiff-base ligands with crystal packing, and also with the stability of the compounds, was presented.

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Sharma, Deeksha, e Prof Arpan Bhardwaj. "A COMPARITIVE VIEW OVER THE SYNTHESIS OF SCHIFF BASE LIGANDS AND METAL COMPLEXES BY CONVENTIONAL AND SOLVENT FREE ROUTES". International Journal of Engineering Technologies and Management Research 4, n. 12 (24 aprile 2020): 107–17. http://dx.doi.org/10.29121/ijetmr.v4.i12.2017.603.

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In the present paper, synthesis of Schiff base ligands and the metal complexes are studied and compared by conventional and solvent free route. The synthesis of Schiff base ligands of amino acids (Glycine, Phenylalanine and Tyrosine) with salicylaldehyde and their mixed ligand ternary Cu(II) complexes are discussed. Other ligands are used in co-ordinaion with the schiff base is 1,10- Phenanthroline/thiourea in equimolar ratio. The environmentally efficient and modern developed method for synthesis is the solid state synthesis of salicylidene amino acids through pestle mortar synthetic procedure. This method is compared with the conventional method that require refluxing the reactant mixture for hours in an organic solvent, here ethanol. The complexes are characterized by spectral techniques IR spectroscopy and UV spectroscopy. The investigations concluded that the pestle mortar assisted method is very rapid , simple and economic for the preparation of ligands and complexes as well. The Antimicrobial studies were also performed for the complexes. The spectral data for the ligands and complexes obtained from either method, conventional and solventless procedure are in good agreement with one another. The azomethine bonding(-CH=N-) between salicylaldehyde amino acids based Schiff bases is described by the IR spectral peak around 1600 cm-1.

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Sobola, Abdullahi, Gareth Watkins e Brecht van. "Synthesis, characterization and biological study of Cu(II) complexes of aminopyridine and (aminomethyl)pyridine Schiff bases". Journal of the Serbian Chemical Society 83, n. 7-8 (2018): 809–19. http://dx.doi.org/10.2298/jsc170913002s.

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The synthesis, characterization and antimicrobial activity determination of some aminopyridine- and (aminomethyl)pyridine?salicylaldimine copper(II) complexes were realized. The ligands, L1?L6, were prepared by condensing salicylaldehyde and o-vanillin with 2- and 3-amino- and (aminomethyl)pyridine, respectively. The complexes were characterized by micro-analytical, electronic, infrared and conductivity data. The structures of the Schiff base ligands were further confirmed from 1H- and 13C-NMR spectral data. This study established that salicylaldimine ligands could coordinate as neutral species via the imine-N and the undeprotonated phenolic-O. The complexes have the molecular formula: [CuLCl], [Cu(LH)2Cl2]?xH2O or [Cu(LH)Cl(H2O)]Cl. The X-ray crystal structure of [CuL6Cl] indicated a square planar geometry with the Schiff base ligand coordinated to the Cu(II) ion as a tridentate monobasic, N2O, ligand. The crystals crystallized in a monoclinic system with P21/c space group. All the ligands and their Cu(II) complexes were screened for their antimicrobial activity against Staphylococcus aureus subsp. aureus ATCC? 6538?*, Bacillus subtillis subsp. spizizenii ATCC? 6633?*, Escherichia coli ATCC? 8739?* and Candida albicans ATCC? 2091?* using agar diffusion and broth dilution techniques. The presence of the methoxyl group enhanced the antimicrobial activity of the salicylaldimine Schiff base ligands.

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Fuentealba, Mauricio, Deborah Gonzalez e Vania Artigas. "Structural Characterization of Iron(iii) Dinuclear Complexes". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1695. http://dx.doi.org/10.1107/s2053273314083041.

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Dinuclear complexes have been studied for different purposes: magnetic materials[1], Non-linear optics materials[2], molecular switches [3], mixed-valence systems, etc. With these antecedents in mind, we present in this work a new series of dinuclear Iron(III) complexes formed by different Schiff bases ligands. The reaction starting from the iron chloride salts with the 5-chloro or 5-bromo-salycilaldehyde and ethylendiamine yields two different kinds of dinuclear iron complexes in different reaction conditions. The first one (Fig N°1), are methoxo-bridged dinuclear iron(III) complexes in which each metal centre is coordinated with one mono-condensated Schiff base ligand, one 4-chloro or 4-bromo-2-(dimethoxymethyl)phenoxo ligand and two bridging methoxo ligands. The iron(III) centres are hexacoordinated (FeN2O4), the coordination sphere is formed by 2 nitrogen atoms of the ethylendiamine fragment, 2 oxygen atoms from the hydroxyl of the Schiff base and two O atoms from the methoxo ligands. Both iron(III) centres are related by a inversion centre. The second one (Fig N°2), the dinuclear complex is formed for the double condensation of ethylendiamine with 5-chloro or 5-bromo-salycilaldehyde and one oxygen from the dianionic ligand act as bridge with another unit. The iron (III) centres are also hexaccordinated (FeN2O3Cl) formed by 2 nitrogen atoms from ethylendiamine fragment and 3 oxygen atoms from hydroxyl from Schiff base ligands and one chloro ligand. Finally, the electronic and redox properties have been studied by UV-Visible and cyclic voltammetry. ACKNOWLEDGMENT FONDECYT N01130640, FONDEQUIP EQM120095 and Beca CONICYT folio 21130944

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Bakhtiari, Atefeh, e Javad Safaei-Ghomi. "Effects of Chiral Ligands on the Asymmetric Carbonyl-Ene Reaction". Synlett 30, n. 15 (23 luglio 2019): 1738–64. http://dx.doi.org/10.1055/s-0037-1611875.

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The carbonyl-ene reaction is one of the most well-known reactions for C–C bond formation. Based on frontier molecular orbitals (FMO), carbonyl-ene reactions occur between the highest occupied molecular orbital (HOMO) of the ene compound bearing an active hydrogen atom at the allylic center and the lowest unoccupied molecular orbital (LUMO) of the electron-deficient enophile, which is a carbonyl compound. A high activation barrier enforces the concerted ene reaction rather than a Diels–Alder reaction at high temperature. Employing a catalytic system can eliminate defects in the ene reaction, and chiral catalysts promote the reaction under mild conditions to produce optically active compounds. In this account, we highlight investigations on the effects of various classes of chiral ligands on intermolecular and intramolecular carbonyl-ene reactions.1 Introduction2 Biaryl-Type Chiral Ligands3 C 1- and C 2-Symmetric Bis(oxazoline) Ligands4 Schiff Base Ligands5 N,N′-Dioxide Ligands6 Conclusions

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Majeed, May S. "Synthesis and Characterization of New Polymeric-Schiff Bases and Their Complexes". BASRA JOURNAL OF SCIENCE 40, n. 3 (1 dicembre 2022): 649–65. http://dx.doi.org/10.29072/basjs.20220309.

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Complexations of three new polymeric Schiff base ligands to transition metals (Ni and Zn) were synthesized via the preparation of a Schiff base ligand on Styrene-allyl alcohol (SAA) and two types of polyvinyl alcohol (PVA). These polymers were a supporting agent for preparing Schiff base ligand on it, followed by complexation with transition metals. Modified SAA and PVA polymers with Ni (II) and Zn (II) have been synthesized in order to investigate some transition metal complexes roles in these polymer modifications. The prepared polymeric complexes were confirmed and characterized by FTIR spectroscopy and TGA instrument respectively. The transition metals (Ni and Zn) content was estimated using SEM-EDX analysis

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Hall, C. Dennis, Niki Sachsinger, Stanley C. Nyburg e Jonathan W. Steed. "Redox-active Schiff base ligands". Journal of Organometallic Chemistry 561, n. 1-2 (giugno 1998): 209–19. http://dx.doi.org/10.1016/s0022-328x(98)00530-0.

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Divya, Kumble, Geetha M. Pinto e Asha F. Pinto. "APPLICATION OF METAL COMPLEXES OF SCHIFF BASES AS AN ANTIMICROBIAL DRUG: A REVIEW OF RECENT WORKS". International Journal of Current Pharmaceutical Research 9, n. 3 (5 maggio 2017): 27. http://dx.doi.org/10.22159/ijcpr.2017.v9i3.19966.

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Schiff bases are versatile ligands which are synthesized from the condensation of primary amines with carbonyl groups. Synthesis of Schiff base transition metal complexes by using Schiff base as ligands appears to be fascinating in view of the possibility of obtaining coordination compounds of unusual structure and stability. These transition metal complexes have received exceptional consideration because of their active part in metalloenzymes and as biomimetic model compounds due to their closeness to natural proteins and enzymes. These compounds are very important in pharmaceutical fields because of their wide spectrum of biological activities. Most of them show biological activities including antibacterial, antifungal, antidiabetic, antitumor, antiproliferative, anticancer, herbicidal, and anti-inflammatory activities. The biological activity of the transition metal complexes derived from the Schiff base ligands has been widely studied. This review summarizes the importance, Scope and antimicrobial activities of Schiff base metal complexes.

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Kassim, Karimah, e Muhamad Azwan Hamali. "Green Synthesis and Antimicrobial Studies of Ni(II) and Zn(II) Dinuclear Schiff Base Complexes". International Journal of Engineering & Technology 7, n. 3.11 (21 luglio 2018): 237. http://dx.doi.org/10.14419/ijet.v7i3.11.16016.

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A series of tetradentate Zn(II) and Ni(II) Schiff base complexes derived from N,N-Bis-(2-hydroxyl-5-methoxybenzaldehyde)-m-phenylenediamine was synthesized using microwave assisted synthesis approach for 5-15 minutes. The confirmation of the ligand as well the respective complexes has been elucidated through physiochemical and spectroscopy analyses. The studies show that two metal ions formed bridges connecting two Schiff base ligands. The nitrogen and oxygen atoms in each ligand served as coordination sites for the metal ions. The Schiff base ligand and complexes were screened for antimicrobial properties using Disc diffusion method against Escherichia coli, Bacillus subtilis, Enterobacter cloacae, and Klebsiella pneumoniae. The screening shows that both Zn(II) and Ni(II) complexes give signif-icant inhibition towards the bacteria tested.

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S. Sharma, S., J. V. Ramani, D. P. Dalwadi, J. J. Bhalodia, N. K. Patel, D. D. Patel e R. K. Patel. "New Ternary Transition Metal Complexes of 2-{[(2-aminophenyl)imino] methyl}Phenol and Metformin: Synthesis, Characterization and Antimicrobial Activity". E-Journal of Chemistry 8, n. 1 (2011): 361–67. http://dx.doi.org/10.1155/2011/723491.

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Complexes of Co(II), Ni(II) and Cu(II) were synthesized from Schiff base 2-{[(2-aminophenyl)imino]methyl}phenol and metformin. The authenticity of the transition metal complexes were characterized by elemental analyses, conductance and magnetic susceptibility measurements, as well as spectroscopic (IR, electronic) and thermal studies. IR spectral studies revealed the existence of the ligands in the amine form in the solid state. The magnetic and electronic spectral studies suggest an octahedral geometry for all the complexes. The metformin acts as a bidentate ligand and Schiff base ofo-phynelendiamine and salicylaldehyde acts as a tridentate ligand. Antimicrobial screening of the Schiff base, metformin and transition metal complexes were determined against the bacteriaEscherichia coliandBacillus megaterium.

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Nguyen, Quang Trung, Phuong Nam Pham Thi e Van Tuyen Nguyen. "Synthesis, Characterization, and In Vitro Cytotoxicity of Unsymmetrical Tetradentate Schiff Base Cu(II) and Fe(III) Complexes". Bioinorganic Chemistry and Applications 2021 (3 maggio 2021): 1–10. http://dx.doi.org/10.1155/2021/6696344.

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Unsymmetrical tetradentate Schiff base Fe(III) and Cu(II) complexes were prepared by the coordination of some unsymmetrical tetradentate Schiff base ligands with CuCl2·2H2O or FeCl3·6H2O. The obtained complexes were characterized by ESI-MS, IR, and UV-Vis. The spectroscopic data with typical signals are in agreement with the suggested molecular formulae of the complexes. Their cyclic voltammetric studies in acetonitrile solutions showed that the Cu(II)/Cu(I) and Fe(III)/Fe(II) reduction processes are at (−)1.882–(−) 1.782 V and at (−) 1.317–(−) 1.164 V, respectively. The in vitro cytotoxicity of obtained complexes was screened for KB and Hep-G2 human cancer cell lines. The results showed that almost unsymmetrical tetradentate Schiff base complexes have good cytotoxicity. The synthetic complexes bearing the unsymmetrical tetradentate Schiff base ligands with different substituted groups in the salicyl ring indicate different cytotoxicity. The obtained Fe(III) complexes are more cytotoxic than Cu(II) complexes and relative unsymmetric Schiff base ligands.

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Jamil, Yasmin Mos'ad, Fathi Mohammed Al-Azab e Nedhal Abdulmawla Al-Selwi. "Novel organophosphorus Schiff base ligands: Synthesis, characterization, ligational aspects, XRD and biological activity studies". Ecletica Quimica 48, n. 3 (1 luglio 2023): 36–53. http://dx.doi.org/10.26850/1678-4618eqj.v48.3.2023.p36-53.

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Six complexes have been synthesized from Cu(II), Ni(II), and Co(II) with new bidentate N2 donor Schiff base ligand (2-methoxybenzalidene-1-phenylsemicarbazide L1) and tridentate N2O donor organophosphorus Schiff base ligand (2-methoxybenzalidenediphenylphosphate-1-phenylsemicarbazide L2). Both ligands were synthesized and characterized by metal analysis, infrared (IR), ultraviolet visible (UV-Vis), and nuclear magnetic resonance (NMR) spectral studies. The chemical structures of the synthesized complexes were characterized using their metal analysis, magnetic susceptibility, molar conductance, IR, and UV-Vis spectra. According to molar ratio studies, the complexes have the composition of ML2 for L1 and ML for L2. The X-ray diffraction (XRD) studies showed that the particle size of ligands and L1 complexes were in nano-range. The ligands and their metal complexes have been screened for their antioxidant, antibacterial and antifungal activity.

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Pavlović, Gordana, Mihael Majer e Marina Cindrić. "A tetranuclear cubane-like nickel(II) complex with a tridentate salicylideneimine Schiff base ligand: tetrakis[μ3-4-methyl-N-(2-oxidophenyl)salicylideneiminato]tetrakis[methanolnickel(II)] methanol 0.8-solvate". Acta Crystallographica Section E Crystallographic Communications 72, n. 12 (10 novembre 2016): 1776–79. http://dx.doi.org/10.1107/s2056989016017722.

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The tetranuclear title complex, [Ni4(C14H11NO2)4(CH3OH)4]·0.8CH3OH, has a distorted cubane topology shaped by four Schiff base ligands. The cubane [Ni4(μ3-O4)] core is formedviathe O atoms from the Schiff base ligands. The octahedrally coordinated NiIIions occupy alternating vertices of the cube. Each NiIIion is coordinated by oneO,N,O′-tridentate dianionic ligand, two O atoms of oxidophenyl groups from adjacent ligands and the O atom of a coordinating methanol molecule. The cubane core is stabilizedviaan intramolecular O—H...O hydrogen bond between the hydroxy group of the coordinating methanol molecules and the phenolate O atom of the aldehyde Schiff base fragment. Additional stabilization is obtainedviaintramolecular C—H...O hydrogen bonds involving aromatic C—H groups and the oxygen atoms of adjacent methanol molecules. In the crystal, complex molecules are linked into chains parallel to thecaxisviaweak C—H...O hydrogen bonds. The partial-occupancy disordered methanol solvent molecule has a site occupancy of 0.8 and is linked to the tetranuclear unitviaan intermolecular C—H...O hydrogen bond involving a phenolate O atom.

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Al-Mosawy, Manar. "Review of the biological effects of Schiff bases and their derivatives, including their synthesis". Medical Science Journal for Advance Research 4, n. 2 (31 luglio 2023): 67–85. http://dx.doi.org/10.46966/msjar.v4i2.117.

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Aldehyde and amine buildup can shape Schiff's base complex of metal. Amino and carbonyl mixtures address a sizable group of ligands used to make Schiff bases that can facilitate with metal particles by the nitrogen iota of an azomethine particle. There has been much interest in these ligands. The C=N connect, in which different azomethines have been researched and professed to overwhelm massive organic activity, like impacts against microorganisms, growths, and infections, as well as against jungle fever and disease, might be the reason for the significance of azomethine replacements. Schiff base metal complexes have recently proven valuable compounds in various fields, including industry and medicine. Schiff's bases are the ideal substance with unmatched organic and inorganic chemistry service. because of the extensive range of biological movements that Schiff base ligand display and their complexes collection, use in clinical applications is observed to have affected the chemistry of Schiff bases, their derivatives, synthesis methods, and the specific biological applications for these compounds, along with the ones for antibacterial, antifungal, anticancer, and antiviral objectives, are defined on this overview. The manufacture, characterization, and biological results of Schiff bases and their derivatives can be discussed in this assessment.

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Ghosh, Subrata, Sukanya Bagchi, Sujit Kamilya e Abhishake Mondal. "Effect of ligand substituents and tuning the spin-state switching in manganese(iii) complexes". Dalton Transactions 50, n. 13 (2021): 4634–42. http://dx.doi.org/10.1039/d1dt00284h.

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This work unravels the magneto-structural behavior of mononuclear manganese(iii) complexes with judiciously chosen substituted Schiff-base ligands, showcasing the role of ligand substitutions in spin-state switching.

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Lian, Wen-Jing, Xin-Tian Wang, Cheng-Zhi Xie, He Tian, Xue-Qing Song, He-Ting Pan, Xin Qiao e Jing-Yuan Xu. "Mixed-ligand copper(ii) Schiff base complexes: the role of the co-ligand in DNA binding, DNA cleavage, protein binding and cytotoxicity". Dalton Transactions 45, n. 22 (2016): 9073–87. http://dx.doi.org/10.1039/c6dt00461j.

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Four novel mixed-ligand copper(ii) Schiff base complexes were synthesized and characterized. The biological features of the complexes and how acetic auxiliary ligands manipulate these features were investigated.

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S P, Sridevi, Girija C R e C. D. Satish. "Synthesis, Structure and Reactivity of Schiff Base Transition Metal Mixed Ligand Complexes Derived from Isatin and Salal". Oriental Journal Of Chemistry 37, n. 1 (28 febbraio 2021): 169–76. http://dx.doi.org/10.13005/ojc/370123.

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A series of Isatin derivative Schiff Base ligands have been prepared by the nucleophilic addition of 5-Bromo Isatin with various amine derivatives and characterized by CHNS analysis and spectral data. Similarly, two of Salicylaldehyde ligand have been prepared by the nucleophilic addition of Salal with amine derivatives. In order to investigate the coordination behavior of these ligands and their metal complexes of the type M(acac)x, L [M = Cu(II), Ni(II); L = Schiff base ligands; x = 0 or 2] mixed ligand (chelate) have been prepared from the reaction of these ligands with their corresponding metal (Ni, Cu) acetylacetonates. The present paper was an approach to understand the chelating mixed ligand formation in complexes. All the isolated Shiff base ligands and mixed acac metal complexes were characterized by using IR, 1H NMR, UV-VIS, molar conductance and TGA/DTA analysis. The biological activities of all the isolated ligands and their corresponding mixed acac metal complexes have been used to screening against the microorganisms both gram positive and gram negative bacteria such as E.coli and S.sureus respectively, fungi A.niger and C.albicans and the results have been compared with standard and control. The main idea of these types of biological screening is to understand the role of these isolated compounds in pharmaceutical industries for drug development.

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Joshi, K. R., A. J. Rojivadiya e J. H. Pandya. "Synthesis and Spectroscopic and Antimicrobial Studies of Schiff Base Metal Complexes Derived from 2-Hydroxy-3-methoxy-5-nitrobenzaldehyde". International Journal of Inorganic Chemistry 2014 (17 novembre 2014): 1–8. http://dx.doi.org/10.1155/2014/817412.

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Abstract (sommario):

Two new series of copper(II) and nickel(II) complexes with two new Schiff base ligands 2-((2,4-dimethylphenylimino)methyl)-6-methoxy-4-nitrophenol and 2-((3,4-difluorophenylimino)methyl)-6-methoxy-4-nitrophenol have been prepared. The Schiff base ligands were synthesized by the condensation of 2-hydroxy-3-methoxy-5-nitrobenzaldehyde with 2,4-dimethylaniline or 3,4-difluoroaniline. The ligands and their metal complexes have been characterized by IR, 1H NMR, mass and electronic spectra and TG analysis. The Schiff base ligands and their metal complexes were tested for antimicrobial activity against Gram positive bacteria Staphylococcus aureus, and Streptococcus pyogenes and Gram negative bacteria Escherichia coli, and Pseudomonas aeruginosa and fungus Candida albicans, Aspergillus niger, and Aspergillus clavatus using Broth Dilution Method.

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25

Wagh, Shaila, e B. R. Patil. "SYNTHESIS, SPECTRAL, THERMAL AND ANTIMICROBIAL STUDIES OF NEW METAL COMPLEXES OF SUBSTITUTED HYDROXY PROPIOPHENONE". RASAYAN Journal of Chemistry 15, n. 03 (2022): 1718–27. http://dx.doi.org/10.31788/rjc.2022.1536355.

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Abstract (sommario):

A new series of metal complexes of innovative bisketimines (L1 - L5) have been synthesized. Schiff base ligands were synthesized by condensing substituted 2’- hydroxy propiophenone and ethylene diamine. The synthesized Schiff bases act as tetradentate ligands with two nitrogen and two phenolic oxygen groups and co-ordinates with Co (II), Ni (II), Cu (II) and Zn (II) salts. Ligands and their metal complexes have been studied using 1H NMR, IR, UV-Vis and thermogravimetric techniques. The complexes were crystalline, according to the XRD pattern. The thermogravimetric data revealed the thermal stability of the complexes. The study of antibacterial and antifungal activities of the ligands and their metal complexes showed more effectiveness of metal complexes than Schiff base ligands.

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26

Sharma, Shobhana, Poonam Yadav, Seema, Suman Kumari e Mamta Ranka. "MICROWAVE-ASSISTED SYNTHESIS OF SCHIFF BASE AND MIXED LIGAND COMPLEXES OF Cr(III): COMPARISON WITH CONVENTIONAL METHOD AND ANTIMICROBIAL STUDIES". RASAYAN Journal of Chemistry 16, n. 02 (2023): 884–91. http://dx.doi.org/10.31788/rjc.2023.1628228.

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Abstract (sommario):

The Sustainable/Greener approach is prioritized over the conventional approach because of its environment-friendly, less time-consuming, less energy-consuming, less hazardous compounds synthesis, and low expenditure. Using a greener approach involving the use of microwave, Cr complexes were synthesized from Schiff base and various bidentate ligands and compared with conventional methods. Condensing 2-amino pyridine and isatin produced Schiff base. Complexes of Cr(III) were synthesized by using some bio-potent secondary ligands with Schiff base. Both Schiff base and complexes were characterized by FTIR spectroscopy, 1H NMR spectroscopy, magnetic moment analysis, elemental investigation, etc. The synthesized compounds will be further used for biological evaluation that can be further used in drugs and agrochemical design.

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27

Yamgar, Ramesh S., Y. Nivid, Satish Nalawade, Mustapha Mandewale, R. G. Atram e Sudhir S. Sawant. "Novel Zinc(II) Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies". Bioinorganic Chemistry and Applications 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/276598.

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Abstract (sommario):

The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria:E. coliandPseudomonas fluorescens, Gram positive bacteria:Staphylococcus aureus,and also against fungi, that is,C. albicansandA. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2 μg/mL). The “in vitro” data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents againstC. albicansandA. niger.

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28

Lumsden, Simone E. A., Gummadi Durgaprasad, Keren A. Thomas Muthiah e Michael J. Rose. "Tuning coordination modes of pyridine/thioether Schiff base (NNS) ligands to mononuclear manganese carbonyls". Dalton Trans. 43, n. 28 (2014): 10725–38. http://dx.doi.org/10.1039/c4dt00600c.

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Abstract (sommario):

Manganese carbonyls are ligated by pyridine/thioether Schiff base (NNS) ligands. Coordination of the thioether-S donor to the Mn(i) center is determined by subtle steric changes at the ligand periphery.

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29

ALI, Safaa Hussein, Hassan Mwazi ABD ALREDHA e Haider Sabah ABDULHUSSEIN. "ANTIBIOTIC ACTIVITY OF NEW SPECIES OF SCHIFF BASE METAL COMPLEXES". Periódico Tchê Química 17, n. 35 (20 luglio 2020): 837–59. http://dx.doi.org/10.52571/ptq.v17.n35.2020.71_ali_pgs_837_859.pdf.

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Abstract (sommario):

Bacterial resistance is a growing challenge facing drug design scientists to find new medications or update commonly used antibiotics. The objective of this study was to synthesize, structure and highlight biological features of new species of metal-organic complexes [(MCl2))2)L1)] {M = Ni, Cu, L1) = N,N’-1,4- Phenylenebis(methanylylidene)bis(ethane-1,2-diamine)} and [(NiCl2))2)L2)]. The Schiff base ligands were prepared in an excellent yeilds by adding terephthalaldehyde to 1,2-ethane-diamine or 1,4-butane-diamine. Three binuclear Schiff base metal complexes were synthesized in a simple one-pot reaction by reacting the corresponding metal chloride (NiCl2) and CuCl2)) salts with the Schiff base ligands {L1) = N,N’-(1,4- phenylenebis(methanylylidene)bis(1,2-diethylamine)) and L2) = N,N’-(1,4- phenylenebis(methanylylidene)bis(butane-1,4-diamine))}. The obtained Schiff base metal complexes were analytically, characterized by a set of spectroscopic techniques such as FT-IR spectroscopy, 1H NMR spectra, and mass spectra. The structures characterization studies suggest that Schiff base ligands behave as N bidentate ligands for nickel and copper metal centers, which are known to act as Lewis acids. The biological activity of the Schiff base of nickel(II) and copper(II) complexes was tested by using the broth dilution method. The complexes showed antibacterial activity against all gram-negative and gram-positive bacteria (Enterobacter cloacae G-, Citrobacter G-, Pseudomonas G-, Klebsiella G-, Staphylococcus G+, and Streptococcus G+) that used in the trials. It is concluded that Schiff base metal complexes are a good candidate for the antibacterial drug because of its good activity against gram-negative and gram-positive strains demonstrated in the present study, as well as in other studies in the literature.

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30

Yadav, Jyoti, e Jai Devi. "Antimicrobial and Antioxidant Activities of Diorganotin(IV) Complexes Synthesized from 1,2,4-Triazole Derivatives". Asian Journal of Chemistry 32, n. 10 (2020): 2553–58. http://dx.doi.org/10.14233/ajchem.2020.22819.

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Abstract (sommario):

Novel diorganotin(IV) complexes were synthesized from 1,2,4-triazole Schiff base ligands which were synthesized by reaction between the 4-amino-5-phenyl-1,2,4-triazole-3-thiol and salicyaldehyde derivatives. The bonding and geometry of the diorganotin(IV) complexes were evaluated by using different spectroscopic techniques such as FT-IR, mass, 1H, 13C & 119Sn NMR. The different spectroscopic techniques revealed the tridentate (ONS) mode of chelation of Schiff base ligands and pentacoordinated environment around the central tin metal which was satisfied with azomethine nitrogen, phenolic oxygen, thiolic sulfur and metal-carbon bond of alkyl/aryl group. The Schiff base ligands and their organotin(IV) complexes were tested for their in vitro antimicrobial and antioxidant activities to examine the biological outline of complexes in comparison to standard drugs. The results of activities data revealed that diorganotin(IV) complexes are more active than Schiff base ligands and some diorganotin(IV) complexes are even more active than the standard drugs. In all the synthesized complexes, compound 9 (Bu2SnL2) and 10 (Ph2SnL2) were most potent and can be used in future clinical trials.

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31

Sreenivas, V., G. Srikanth, Ch Vinutha, M. Shailaja, P. Muralidhar Reddy e Ravinder Vadde. "Synthesis, Spectral Characterization and Antimicrobial Studies of Co(II) Complexes with Tetradentate Schiff bases Derived from Ortho-Phthalaldehyde". JOURNAL OF ADVANCES IN CHEMISTRY 9, n. 1 (1 maggio 2016): 1873–82. http://dx.doi.org/10.24297/jac.v9i1.2852.

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Abstract (sommario):

A series of cobalt (II) complexes have been synthesized with Schiff bases derived from ortho-phthalaldehyde and various amines in aqueous methanol solution. The newly synthesized Schiff bases and their Co (II) complexes have been characterized by elemental analysis, magnetic susceptibility, thermal, conductance measurements, mass, IR, electronic, 1H,13C-NMR spectral techniques. These ligands act as tetradentate species and coordinate to the metal center through the different potential donor atoms such as N, O and S. The probable octahedral structures have been assigned to these complexes. All the synthesized Schiff base ligands and Co(II) metal complexes have also been screened for their antimicrobial activities and metal complexes found to be more active than respective Schiff-base ligands.

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32

Halevas, Eleftherios, Antonios Hatzidimitriou, Barbara Mavroidi, Marina Sagnou, Maria Pelecanou e Dimitris Matiadis. "Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex". Molbank 2021, n. 1 (6 gennaio 2021): M1179. http://dx.doi.org/10.3390/m1179.

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Abstract (sommario):

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

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33

Ejidike, Ikechukwu P., e Peter A. Ajibade. "Transition metal complexes of symmetrical and asymmetrical Schiff bases as antibacterial, antifungal, antioxidant, and anticancer agents: progress and prospects". Reviews in Inorganic Chemistry 35, n. 4 (1 dicembre 2015): 191–224. http://dx.doi.org/10.1515/revic-2015-0007.

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Abstract (sommario):

AbstractThe huge research on Schiff base coordination complexes in the past few decades has given rise to several new molecules that have been of biological importance. The ease with which the Schiff base ligands are designed and prepared and their pattern is elucidated have made them to be referred to as “fortunate ligands” possessing azomethine derivatives, the C=N linkage that is essential for biological activity, including antibacterial, antifungal, antioxidant, anticancer, and diuretic activities. A variety of Schiff base and its complexes have been studied as model molecules for biological oxygen carrier systems. The uses of Schiff bases as DNA-cleaving agents and its mode of interaction and free-radical scavenging properties are described. The review encapsulates the applications of Schiff bases and their complexes.

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34

Deng, Ji-Hua, Gui-Quan Guo e Di-Chang Zhong. "Bis[N-aminocarbonyl-N′-(3-pyridylmethylene-κN)hydrazine]diaquabis(thiocyanato-κN)zinc(II)". Acta Crystallographica Section E Structure Reports Online 63, n. 11 (10 ottobre 2007): m2696—m2697. http://dx.doi.org/10.1107/s1600536807048908.

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Abstract (sommario):

The Zn atom of the title complex, [Zn(NCS)2(C7H8N4O)2(H2O)2] or [Zn(SCN)2(H-Pysc)2(H2O)2] [H-Pysc = N-aminocarbonyl-N′-(3-pyridylmethylene)hydrazine], derived from the condensation of pyridine-3-carbaldehyde and semicarbazone, is located at a crystallographic centre of inversion and is octahedrally coordinated by two thiocyanate anions, two aqua molecules and two molecules of the neutral Schiff base ligand H-Pysc. The Schiff base molecules act as monodentate ligands coordinating the metal through the pyridyl N atom, whereas the amide O and imine N atoms remain uncoordinated. The crystal packing is stabilized by intermolecular hydrogen bonds involving H-Pysc ligands, thiocyanate anions and water molecules.

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35

Devi, Jai, Som Sharma e Sanjeev Kumar. "Synthesis, spectral studies and antimicrobial evaluation of transition metal complexes of bidentate Schiff base ligands derived from 4-amino quinoline". Research Journal of Chemistry and Environment 26, n. 5 (25 aprile 2022): 56–70. http://dx.doi.org/10.25303/2605rjce5670.

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Abstract (sommario):

Coordination compounds of Co(II) , Ni(II), Cu(II) and Zn(II) of the type [M(L1-2)2(H2O)2] were obtained from Schiff base ligands [HL1-2] by the condensation reaction of 5-bromosalicyldehyde/5-chlorosalicyldehyde with 4-amino quinoline using methanol as a solvent in (1:1) molar ratio. The metal complexes were synthesized by reacting the aqueous methanolic solution of metal acetates M(CH3COO)2xH2O with the hot methanolic solution of their respective Schiff base ligands in (1:2) molar ratio. Various physicochemical techniques i.e. elemental analysis, molar conductance measurements, magnetic moment studies and different spectral studies (1H NMR, 13C NMR, UV–Vis, FT-IR, ESR) and mass spectrometry were used for characterization of compounds. The spectral data confirmed the bidentate nature (NO) of Schiff base ligands coordinating through nitrogen atom of azomethine group and oxygen atom of hydroxyl group resulting in the formation of octahedral geometry of all metal complexes. The Schiff base ligands and their transition metal complexes were screened against two gram-positive bacterial species i.e. (S. aureus, B. subtilis), two-gram negative bacterial species i.e. (E. coli, P. aeruginosa) and two fungal species (A. niger and C. albicans) using serial dilution method with ciprofloxacin and fluconazole as reference drug. The results obtained from antimicrobial studies showed that metal complexes are more active than their respective Schiff base ligands. Complex 5 and 6 are potent antimicrobial agent.

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36

Prakash, Sachin, Anju K. Gupta, Shivani Prakash, K. R. R. P. Singh e D. Prakash. "Synthesis and characterization of heterobinuclear copper(II) complexes derived from Schiff base with organosilver(I)". Research Journal of Chemistry and Environment 26, n. 2 (25 gennaio 2022): 126–30. http://dx.doi.org/10.25303/2602rjce126130.

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Abstract (sommario):

Copper(II) ion can form complexes with varied ligands. The present study describes the synthesis of a series of new hetero binuclear Schiff base complexes of copper(II) and organic chelates of silver(I). The Schiff base ligand was derived from salicylaldehyde and ophenylenediamine. For the characterization of the hetero binuclear complexes, various physicoanalytical and spectral studies viz. elemental analysis, magnetic moment measurements, molar conductance, FTIR and electronic spectral recordings were applied. Evidences from these analyses reveal square geometry for the complexes.

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37

Rajak, Ashish, Arpit Srivastava, Gyanendra Kumar Bharati, Subhash Chandra Shrivastava e Shekhar Srivastava. "Synthesis and characterization of Ru (II) complexes with macrocyclic ligands". Research Journal of Chemistry and Environment 26, n. 8 (25 luglio 2022): 153–64. http://dx.doi.org/10.25303/2608rjce1530164.

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Abstract (sommario):

Ten complexes of the type [RuCl2(L1-10)] (where L= macrocyclic Schiff base ligands) have been synthesized by reaction of [RuCl2(DMSO)4] with ten macrocyclic Schiff base ligands. These complexes were characterized by elemental analysis, molar conductance; UV-Visible spectra, IR, magnetic movement and X-ray photoelectron spectra (XPS). An octahedral geometry was established for all these complexes.

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38

Kumar, Naresh, Pawan Kumar e Sanjeev Kumar. "Synthesis and Characterization of Benzothiazole Derivative of Schiff Base ligand and its Complexes". Research Journal of Chemistry and Environment 26, n. 12 (25 novembre 2022): 68–70. http://dx.doi.org/10.25303/2612rjce068070.

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Abstract (sommario):

Schiff Base Complexes are very important. Benzothiazole and its derivatives play an important role in biological activities like anticancer agent, antidiabetic agent, antiinflammatory agent, antimalarial agent etc. while its Schiff base also plays an important role. This study deals with synthesis and characterization of condensation products of ABT derivatives with Schiff base. Schiff base ligands of BT and Ni(II) complex were synthesized and important characterizations have been studied. Schiff base obtained shows very effective biological activities while complex of Ni(II) is also important for that very purpose.

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39

Renehan, Marie F., Hans-Jörg Schanz, Eoghan M. McGarrigle, Cormac T. Dalton, Adrian M. Daly e Declan G. Gilheany. "Unsymmetrical chiral salen Schiff base ligands". Journal of Molecular Catalysis A: Chemical 231, n. 1-2 (aprile 2005): 205–20. http://dx.doi.org/10.1016/j.molcata.2004.12.034.

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40

Lam, Fung, Jia Xi Xu e Kin Shing Chan. "Binucleating Ligands: Synthesis of Acyclic Achiral and Chiral Schiff Base−Pyridine and Schiff Base−Phosphine Ligands". Journal of Organic Chemistry 61, n. 24 (gennaio 1996): 8414–18. http://dx.doi.org/10.1021/jo961020f.

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41

Imran, Muhammad, Mitu Liviu, Shoomaila Latif, Zaid Mahmood, Imtiaz Naimat, Sana Zaman e Surrya Fatima. "Antibacterial Co(II), Ni(II), Cu(II) and Zn(II) complexes with biacetyl-derived Schiff bases". Journal of the Serbian Chemical Society 75, n. 8 (2010): 1075–84. http://dx.doi.org/10.2298/jsc091026098i.

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Abstract (sommario):

The condensation reactions of biacetyl with orthohydroxyaniline and 2-aminobenzoic acid to form bidendate NO donor Schiff bases were studied. The prepared Schiff base ligands were further utilized for the formation of metal chelates having the general formula [ML2.2H2O] where M = Co(II), Ni(II), Cu(II) and Zn(II) and L = HL1 and HL2. These new compounds were characterized by conductance measurements, magnetic susceptibility measurements, elemental analysis, and IR, 1H-NMR and electronic spectroscopy. Both Schiff base ligands were found to have a mono-anionic bidentate nature and octahedral geometry was assigned to all metal complexes. All the complexes contained coordinated water which was lost at 141-160 ?C. These compounds were also screened for their in-vitro antibacterial activity against four bacterial species, namely; Escherichia coli, Staphylococcus aureus, Salmonella typhi and Bacillus subtillis. The metal complexes were found to have greater antibacterial activity than the uncomplexed Schiff base ligands.

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42

Şabik, Ali E., Muharrem Karabörk, Gökhan Ceyhan, Mehmet Tümer e Metin Dığrak. "Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties". International Journal of Inorganic Chemistry 2012 (16 maggio 2012): 1–11. http://dx.doi.org/10.1155/2012/791219.

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Abstract (sommario):

We synthesized the Schiff base ligands H2L1–H2L4 and their La(III) complexes and characterized them by the analytical and spectroscopic methods. We investigated their electrochemical and antimicrobial activity properties. The electrochemical properties of the ligands H2L1–H2L4 and their La(III) complexes were studied at the different scan rates (100 and 200 mV), different pH ranges (), and in the different solvents. The electrooxidation of the Schiff base ligands involves a reversible transfer of two electrons and two protons in solutions of pH up to 5.5, in agreement with the one-step two-electron mechanism. In solutions of pH higher than 5.5, the process of electrooxidation reaction of the Schiff base ligands and their La(III) complexes follows an ECi mechanism. The antimicrobial activities of the ligands and their complexes were studied. The thermal properties of the metal complexes were studied under nitrogen atmosphere in the range of temperature 20–1000°C.

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43

Gupta, Mridula, e Sheela M. Valecha. "Synthesis and Characterization of New Palladium(II) Schiff Base Complexes Derived from β-Diketones and Diamines". Asian Journal of Chemistry 32, n. 5 (2020): 1039–42. http://dx.doi.org/10.14233/ajchem.2020.22502.

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Abstract (sommario):

A new series of heterocyclic Schiff bases were prepared from condensation of 1-phenyl-3-methyl-4-acetyl/benzoyl-pyrazolone with 4,4′-diaminodiphenylmethane and 4,4′-diaminodiphenyl ether, resulting in the formation of four novel Schiff base ligands. These ligands were then treated with ethanolic solution of PdCl2, to form corresponding palladium(II) complexes. These complexes were characterized by elemental analysis, IR, 1H NMR, TGA, magnetic susceptibility measurements and UV-visible absorption spectroscopy. All the Pd(II) complexes were found to have one coordinated water molecule. Schiff base ligands chelated with the metal atom through two donor sites N and O of azomethine (-C=N-) and phenolic (-OH) groups, respectively.

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44

Isyaku, S., H. N. Aliyu, E. C. Ozoro e T. Abubakar. "Synthesis, characterization and antimicrobial studies of Mn(II) complexes of acetylthiophene and acetyl Furan Schiff base derivatives". Bayero Journal of Pure and Applied Sciences 12, n. 1 (15 aprile 2020): 85–92. http://dx.doi.org/10.4314/bajopas.v12i1.15s.

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Abstract (sommario):

Manganese (II) complexes of Schiff bases; 2-acetylthiophene 4‑phenylthiosemi-carbazone (AT-PTSC) and 2-furylmethylketone-4-phenylthiosemi-carbazone (AF‑PTSC) derived from condensation of 2-acetylthiophene and 2-furylmethylketone (2-acetylfuran) each with 4-phenylthiosemicarbazide in (1:1 molar ratio) ethanol, have been synthesized. The Schiff bases and the Mn(II) complexes were characterized on the basis of melting point/decomposition temperature, solubility, magnetic susceptibility, infrared spectra, molar conductance measurements, elemental and gravimetric analyses. The Mn(II) complexes show moderate values of decomposition temperatures. The Schiff bases and the complexes were soluble in some common organic solvents. Infrared spectral data of the Schiff bases and their complexes, indicate coordination of the Schiff bases to the metal(II) ion via azomethine nitrogen. The effective magnetic moment of the Mn(II) complexes suggested an octahedral geometry. The molar conductance values of the complexes show that the complexes are electrolytes. The results of the elemental analysis of the ligands and their complexes are in good agreement with the calculated values, suggesting a 1:2 (metal-ligand) ratio. Antimicrobial screenings of the ligands and their complexes were conducted against gram-positive (Staphylococcus aureus,) and two gram-negative (Salmonella typhii, and Escherichia coli) bacteria specie. Also three fungi mainly (Candida albicans, Mucus indicus and Aspergillus flavus) were tested. The results showed that both the ligands and the complexes are active against the bacteria and the fungi specie. Keywords: Ligand, Schiff base, 4-phenylthiosemicarbazide, 2-acetylthiophene, 2-acetylfuran molar conductivity, magnetic susceptibility, elemental analysis.

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45

Isyaku, S., H. N. Aliyu, E. C. Ozoro e T. Abubakar. "Synthesis, characterization and antimicrobial studies of Mn(II) complexes of acetylthiophene and acetyl furan Schiff base derivatives". Bayero Journal of Pure and Applied Sciences 12, n. 1 (15 aprile 2020): 251–58. http://dx.doi.org/10.4314/bajopas.v12i1.39s.

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Abstract (sommario):

Manganese(II) complexes of Schiff bases; 2-acetylthiophene-4‑phenylthiosemi-carbazone (AT-PTSC) and 2-furylmethylketone-4-phenylthiosemi-carbazone (AF‑PTSC) derived from condensation of 2-acetylthiophene and 2-furylmethylketone (2-acetylfuran) each with 4-phenylthiosemicarbazide in (1:1 molar ratio) ethanol, have been synthesized. The Schiff bases and the Mn(II) complexes were characterized on the basis of melting point/decomposition temperature, solubility, magnetic susceptibility, infrared spectra, molar conductance measurements, elemental and gravimetric analyses. The Mn(II) complexes show moderate values of decomposition temperatures. The Schiff bases and the complexes were soluble in some common organic solvents. Infrared spectral data of the Schiff bases and their complexes, indicate coordination of the Schiff bases to the metal(II) ion via azomethine nitrogen. The effective magnetic moment of the Mn(II) complexes suggested an octahedral geometry. The molar conductance values of the complexes show that the complexes are electrolytes. The results of the elemental analysis of the ligands and their complexes are in good agreement with the calculated values, suggesting a 1:2 (metal-ligand) ratio. Antimicrobial screenings of the ligands and their complexes were conducted against gram-positive (Staphylococcus aureus,) and two gram-negative (Salmonella typhi, and Escherichia coli) bacteria specie. Also three fungi mainly (Candida albicans, Mucus indicus and Aspergillus flavus) were tested. The results showed that both the ligands and the complexes are active against the bacteria and the fungi specie. Keywords: Ligand, Schiff base, 4-phenylthiosemicarbazide, 2-acetylthiophene, 2-acetylfuran molar conductivity, magnetic susceptibility, elemental analysis.

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46

Barati, Kazem, William Clegg, Mohammad Hossein Habibi, Ross W. Harrington, Arash Lalegani e Morteza Montazerozohori. "Synthesis and crystal structure of the dinuclear copper(II) Schiff base complex μ-hydroxido-μ-chlorido-bis{[bis(trans-2-nitrocinnamaldehyde)ethylenediamine]chloridocopper(II)} dichloromethane sesquisolvate". Acta Crystallographica Section C Structural Chemistry 72, n. 3 (26 febbraio 2016): 239–42. http://dx.doi.org/10.1107/s2053229616003144.

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Abstract (sommario):

Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff baseN,N′-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1′E,2E,2′E)-N,N′-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ-chlorido-μ-hydroxido-bis(chlorido{(1E,1′E,2E,2′E)-N,N′-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ2N,N′}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four-membered ring in an unsymmetrical Cu2OCl3core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two CuIIatoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five-coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring-stacking interactions supported by C—H...Cl interactions with solvent molecules; a further ring-stacking interaction exists between the two Schiff base ligands of each molecule.

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47

Chakraborty, Prateeti, Ishani Majumder, Kazi Sabnam Banu, Bipinbihari Ghosh, Hulya Kara, Ennio Zangrando e Debasis Das. "Mn(ii) complexes of different nuclearity: synthesis, characterization and catecholase-like activity". Dalton Transactions 45, n. 2 (2016): 742–52. http://dx.doi.org/10.1039/c5dt03659c.

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Abstract (sommario):

The origin of catecholase-like activity of Mn(ii)–Schiff-base complexes has been explored by studying structurally characterized mono-, di- and polynuclear Mn(ii) complexes of two “end-off” compartmental Schiff-base ligands.

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48

Lam, Fung, e Kin Shing Chan. "Synthesis of acyclic dinucleating Schiff base-pyridine and schiff base-phosphine ligands". Tetrahedron Letters 36, n. 6 (febbraio 1995): 919–22. http://dx.doi.org/10.1016/0040-4039(94)02372-i.

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49

Kaye, Perry T., e Kevin W. Wellington. "DESIGNER LIGANDS. VII.1SYNTHESIS OF BIOMIMETIC SCHIFF-BASE LIGANDS". Synthetic Communications 31, n. 16 (gennaio 2001): 2405–11. http://dx.doi.org/10.1081/scc-100105116.

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50

Coles, Simon J., Michael B. Hursthouse, David G. Kelly, Andrew J. Toner e Neil M. Walker. "Schiff base insertion in titanium alkyls; reduction of imine functions by benzyl addition". Canadian Journal of Chemistry 77, n. 12 (5 dicembre 1999): 2095–98. http://dx.doi.org/10.1139/v99-205.

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Abstract (sommario):

TiBz4 reacts with N-2-fluorenyl(salicylideneimine) to afford a crystallographically characterized titanium(IV) complex containing two conventional bidentate Schiff base ligands and two O-bound ligands in which the imine function has been reduced by the addition of benzyl and hydrogen moieties.Key words: insertion, nucleophilic additions, Schiff bases, titanium

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