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Moeng, Mmushi Moses. "Terthienyl carbene complexes". Diss., Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-02092006-153600/.
Pełny tekst źródłaLu, Xiaosong. "Generation and reactions of aryloxy and diaryloxycarbenes /". *McMaster only, 2001.
Znajdź pełny tekst źródłaFrankowski, Kevin J. "Carbenes and carbenoids as powerful tools in organic synthesis". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.18 Mb., 94 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3205422.
Pełny tekst źródłaMerkley, Nadine. "Carbenes and radicals from benzyloxy [delta]3-1,3,4-oxadiazolines /". *McMaster only, 2001.
Znajdź pełny tekst źródła[Delta] in title is a Greek letter. The number 3 in title is superscript. Includes bibliographical references (leaves 147-162). Also available via World Wide Web.
El-Saidi, Manal M. T. "Synthesis and thermolysis of 2,2-dioxy-5,5-dimethyl-[delta three]-1,3,4-oxadiazolines : dioxycarbenes and their reactions /". *McMaster only, 1996.
Znajdź pełny tekst źródłaCouture, Philippe. "Syntheses and reactions of aminooxycarbenes from thermolysis of [Delta3]-1,3,4-oxadiazolines /". *McMaster only, 1997.
Znajdź pełny tekst źródłaLian, Yiqian. "Chromium and iron organometallics in organic synthesis synthetic studies toward total synthesis of taxol and chromium to iron transfer processes /". Diss., Connect to online resource - MSU authorized users, 2006.
Znajdź pełny tekst źródłaAsay, Matt J. "Ylides stabilization of novel, low valent carbon-based ligands with applications in catalysis /". Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3350076.
Pełny tekst źródłaIncludes abstract. Title from first page of PDF file (viewed Mar. 8, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
Rafael, Christopher Carlos Ferreira. "Synthesis of chromium carbene scaffolds for use in medicinal chemistry". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1010863.
Pełny tekst źródłaOlivier, Andrew John. "Novel carbene complexes with pyrrole ligands". Diss., Pretoria : [s.n, 2001. http://upetd.up.ac.za/thesis/available/etd-02242006-125303/.
Pełny tekst źródłaBruno, Deborah Suzanne. "Synthesis and thermal decomposition of [CM(CO)CH₂S(Ph)CH₂CH=CH₂] BF₄, M=Fe, Ru". Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/27663.
Pełny tekst źródłaChu, Wai-kin, i 朱煒堅. "Syntheses, spectroscopy and photophysics of ruthenium(II) carbene complexes and diimine complexes with functionalized ligands formolecular recognition and organized assembly". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31240082.
Pełny tekst źródłaWang, Jian. "Heteroaryl(trifluoromethyl)carbenes and related strained cumulenes under matrix isolation conditions". abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3289461.
Pełny tekst źródłaJulius, Gerrit Richard. "New transition metal carbene complexes for application in homogeneous catalysis /". Link to the online version, 2005. http://hdl.handle.net/10019/1063.
Pełny tekst źródłaEtogo, Anthony O. "Late transition metal chemistry of imidazole-based N-heterocyclic carbene ligands synthesis, characterization and luminescence /". abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3209961.
Pełny tekst źródłaAngrish, Deepshikha. "Catalytic transformations via metallocarbenes". Thesis, University of Oxford, 2007. http://ora.ox.ac.uk/objects/uuid:dd93e21b-7e8a-44dc-b2f5-49fc670e065c.
Pełny tekst źródłaQuezada, Carol A. "N-Heterocyclic Carbenes: From Heterocyclynes to Potential Radiopharmaceuticals". Akron, OH : University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1116249871.
Pełny tekst źródłaDuan, Gongping. "Design, synthesis, and photophysics and photochromic study of dithienylethene-containing heterocyclic derivatives and N-heterocyclic carbene-ruthenium (II) complexes". Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B44248246.
Pełny tekst źródłaAu, Ka-man, i 區嘉雯. "Luminescent cyclometalated gold (III) complexes with ancillary N-heterocyclic carbene and alkynyl ligands : from design, synthesis, photophysics to supramolecular assembly and functions". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hdl.handle.net/10722/207995.
Pełny tekst źródłapublished_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
Tian, Weiwei. "Rhodium-mediated carbene insertion synthesis of (-)-hamigeran B and the (-)-sordaricin core /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 119 p, 2008. http://proquest.umi.com/pqdweb?did=1609287781&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Pełny tekst źródłaMeyer, Annalene. "The synthesis of α-alkoxy and α-aminostannanes as precursors to Novel Chromium Fischer Carbenes". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005036.
Pełny tekst źródłaStander, Elzet. "Nuwe reaksies van gedeprotoneerde Fischer-tipe karbeenkomplekse". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1222.
Pełny tekst źródłaHesler, Valerie Jane. "N-Heterocyclic carbene-metal complexes derived from imidazolium-linked cyclophane and biimidazolium salts". University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0088.
Pełny tekst źródłaBaba, Eduard. "N-Heterocyclic Carbenes of the Late Transition Metals: A Computational and Structural Database Study". Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc4792/.
Pełny tekst źródłaLam, Sze-kui. "An asymmetric carbene cyclization cycloaddition strategy toward the synthesis of indicol". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36631863.
Pełny tekst źródłaAksın, Özge Artok Levent. "The activity of silica immobilized palladium N-heterocyclic carbene complexes toward Mizoro-Heck reaction and their characterization/Özge Aksın;thesis advisor Levent Artok". [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimya/T000341.pdf.
Pełny tekst źródłaKeywords: Palladium, Immobilization, Heck Reaction, Palladium-N-Heterocyclic Carbene, Carbon-Carbon Coupling. Includes bibliographical references (leaves. 89-104).
Truscott, Byron John. "The design and synthesis of multidentate N-heterocyclic carbenes as metathesis catalyst ligands". Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1004962.
Pełny tekst źródłaAnnapureddy, Raja Sekarreddy. "Ruthenium porphyrin catalyzed carbene mediated C-H insertion and cycloaddition reactions". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/206316.
Pełny tekst źródłaMoore, Adam L. "N-heterocyclic carbenes with pendant arylamine donor substituents as supports for metal-metal interactions of closed shell metal ions". abstract, 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3326620.
Pełny tekst źródłaZhou, Congying. "Ruthenium porphyrins and dirhodium (II, II) carboxylates catalyzed ylide-mediated cycloadditions and carbenoid transfer reactions". Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31046484.
Pełny tekst źródłaDupuy, Stéphanie. "N-heterocyclic carbene gold hydroxide complexes as bond activation reagents". Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6613.
Pełny tekst źródłaZinser, Caroline Magdalene. "Palladium and gold N-heterocyclic carbene complexes : synthesis and catalytic applications". Thesis, University of St Andrews, 2019. http://hdl.handle.net/10023/17066.
Pełny tekst źródłaMakanjee, Che Azad. "An experimental and theoretical investigation of unstable Fischer chromium carbene complexes". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002953.
Pełny tekst źródłaMicrosoft� Office Word 2007
Pezacki, John Paul. "Rate constants and mechanisms for reactions of carbenes and cations from oxadiazolines and other precursors /". *McMaster only, 1998.
Znajdź pełny tekst źródłaLi, Yan, i 李艷. "Synthesis and reactivity of carbene complexes of iron, ruthenium and osmium porphyrins". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31245730.
Pełny tekst źródłaPolshakov, Dmitrii Arkadyevich. "Ultrafast spectroscopy and dynamics of nitrenes and carbenes". Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1130968887.
Pełny tekst źródłaZhou, Congying, i 周聰穎. "Ruthenium porphyrins and dirhodium (II, II) carboxylates catalyzed ylide-mediated cycloadditions and carbenoid transfer reactions". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31046484.
Pełny tekst źródłaZou, Taotao, i 邹滔滔. "Anti-cancer N-heterocyclic carbene complexes of gold(III), gold(I) and platinum(II) : thiol "switch-on" fluorescent probes, thioredoxin reductase inhibitors and endoplasmic reticulum targeting agents". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/208614.
Pełny tekst źródłaDu, Toit Aletta. "Anioniese Fischer-tipe karbeenkomplekse as ligande". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53280.
Pełny tekst źródłaDu, Toit Maria. "Nuwe karbeenkomplekse en die 'kompleks van komplekse' konsep in ligandontwerp". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53530.
Pełny tekst źródłaLam, Sze-kui, i 林詩鉅. "An asymmetric carbene cyclization cycloaddition strategy toward the synthesis of indicol". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36631863.
Pełny tekst źródłaDuan, Gongping, i 段公平. "Design, synthesis, and photophysics and photochromic study of dithienylethene-containing heterocyclic derivatives and N-heterocycliccarbene-ruthenium (II) complexes". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44248246.
Pełny tekst źródłaKruger, Anneke. "N-heterosikliese karbeenkomplekse van groep 10 metale : nuwe moontlikhede". Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19636.
Pełny tekst źródłaENGLISH ABSTRACT: This study comprises the synthesis and characterisation of N-heterocyclic carbene complexes of group 10 metals with the main focus on such complexes with the nucleophilic N-atom in a position further than the α-position from the carbene carbon atom. These compounds were synthesised by the initial alkylation of quinoline- and acridine derivatives followed by the oxidative addition of the resulting salts to the complexes M(PPh3)4 (M = Ni, Pd, Pt). To complete the study an investigation of the catalytic activity and stability of such compounds in C,C-coupling catalysis was conducted. The carbene ligands used differed with respect to the position of the N-atom relative to the carbene carbon atom as well as with respect to substituents. The oxidative addition of the quinolinium- and acridiniumchloride salts to Ni(PPh3)4 was initially problematic. The desired product formed only in small amounts and could not be isolated easily. However, by replacing toluene with more polar THF as solvent, the nickel complexes could be synthesised in high yield without any indication of decomposition. Oxidative addition to Pt(PPh3)4 also yielded the desired product, although a number of by-products were formed as well. The molecular structure of trans-chloro(1,3-dimethyl-1,2-dihydroquinoline-2-ylidene)-bis(triphenylphosphine) platinum(II) trifluoromethanesulfonate could nevertheless be determined by X-ray crystallography. The new one-N, six membered, heterocyclic carbene complexes were all unambiguously characterised by NMR spectroscopy, mass spectrometry and X-ray crystallography. The carbene character of the complexes was corroborated by a large downfield chemical shift (δ 203 – 230) of the carbene carbon atoms in their 13C NMR spectra. The analyses furthermore indicated that with the exception of cis-chloro(1-methyl-3-phenyl-1,4-dihydroquinoline-4- ylidene)bis(triphenylphosphine)palladium(II) hexafluorophosphate, all the palladium, nickel and platinum complexes exhibit a trans arrangement of the PPh3 ligands. Both the cis- and the trans isomers of the complexes, chloro(1,3-dimethyl-1,2-dihydroquinoline-2-ylidene)- bis(triphenylphosphine)palladium(II) tetrafluoroborate and chloro-(1,3-dimethyl-1,2-dihydroquinoline- 2-ylidene)bis(triphenylphosphine)palladium(II) trifluoromethanesulphonate are, however, present in solution. The molecular structure of both isomers were determined by Xray crystallography. Crystallographic studies revealed that the new family of cationic complexes exist in a slightly distorted square planar environment with the carbene ligand orientated almost perpendicular to this plane. The metal-carbene bond lengths are insensitive to variations in the substituents on the carbene ligands and are therefore not a suitable parameter to distinguish between the strengths of these bonds. The N-heterocyclic carbene ligands with the N-atom removed from the carbene carbon atom by three bonds, exhibit a greater trans influence in the palladium complexes than those with the N-atom in the α-position. This is an indication of the better σ-donor ability of the former. A significant difference in the Ni-Cl bond lengths could, however, not be detected. The catalytic activity of the new synthesised palladium and nickel complexes in the Mizoroki- Heck and Suzuki-Miyaura coupling reactions, were investigated. The palladium complexes tested show potential as precatalysts for the Mizoroki-Heck reaction, although relatively high temperatures were needed to effect coupling, while coupling of aryl chlorides did not occur at all. The trans-chloro(1,2-dimethyl-1,4-dihydroquinoline-4-ylidene)bis(triphenylphosphine)- palladium(II) trifluoromethanesulphonate complex also displayed high activity in the C,Ccoupling of bromofluorene with arylboronic acids in the Suzuki-Miyaura coupling reaction. It even yielded high conversions in instances where sterically hindered aryl halides were used. The trans-chloro(1,2-dimethyl-1,4-dihydroquinoline-4-ylidene)bis(triphenylphosphine)- nickel(II) trifluoromethanesulphonate complex catalyses the coupling of sterically hindered arylbromides as well as arylchlorides to arylboronic acids. By further optimising the reaction conditions and increasing the streric bulk of the carbene ligands, even better results in both the Mizoroki-Heck and the Suzuki-Miyaura reactions are expected.
AFRIKAANSE OPSOMMING: Hierdie studie behels die sintese en karakterisering van N-heterosikliese karbeenkomplekse van groep 10 metale. Daar is veral gefokus op N-heterosikliese karbeenligande waarin die nukleofiele N-atoom verder as die α-posisie vanaf van die karbeenkoolstofatoom verwyder is. Die betrokke komplekse is gesintetiseer deur die alkilering van kinolien- en akridienderivate, gevolg deur die oksidatiewe addisie van die resulterende soute aan die komplekse M(PPh3)4 (M = Ni, Pd, Pt). Om die studie af te rond is die katalitiese aktiwiteit van dié komplekse in C,C-koppelingsreaksies ondersoek. Karbeenligande wat slegs een nukleofiele stikstofatoom besit en verskil ten opsigte van die posisie van dié atoom relatief tot die karbeenkoolstofatoom asook substituente aan die ligand, is gebruik. Die oksidatiewe addisie van die kinoliniumchloried- en akridiniumchloriedsoute aan Ni(PPh3)4 het aanvanklik probleme opgelewer, sodat slegs ’n klein hoeveelheid van die verlangde produk, wat moeilik isoleerbaar was, gevorm het. Deur egter ’n meer polêre oplosmiddel, THF, in plaas van tolueen te gebruik, kon die nikkelkomplekse met goeie opbrengs en sonder enige aanduiding van ontbinding, berei word. Oksidatiewe addisie aan Pt(PPh3)4 het die verlangde produk gelewer, alhoewel ’n aantal neweprodukte ook gevorm het. Ten spyte hiervan is daarin geslaag om die molekulêre struktuur van trans-chloro(1,3- dimetiel-1,2-dihidrokinolien-2-ilideen)bis(trifenielfosfien)platinum(II) trifluorometaansulfonaat kristallografies te bepaal. Die nuwe gesintetiseerde een-N, seslid, heterosikliese karbeenkomplekse is deur KMRspektroskopie, massaspektrometrie en X-straalkristallografie eenduidig gekarakteriseer. Die karbeenkarakter van die komplekse is bevestig deur die ver veldafwaartse chemiese verskuiwing (δ 203 - 230) van die karbeenkoolstofatoom in die 13C-KMR-spektra. Die analises toon ook dat, met die uitsondering van cis-chloro(1-metiel-3-feniel-1,4- dihidrokinolien-4-ilideen)bis(trifenielfosfien)palladium(II) heksafluorofosfaat, al die palladium-, nikkel- en platinumkomplekse ’n trans-rangskikking van die PPh3-ligande besit. Die cis- sowel as die trans-isomere van die palladiumkomplekse chloro(1,3-dimetiel-1,2- dihidrokinolien-2-ilideen)bis(trifenielfosfien)palladium(II) tetrafluoroboraat en chloro(1,3- dimetiel-1,2-dihidrokinolien-2-ilideen)bis(trifenielfosfien)palladium(II) trifluorometaansulfonaat, is in oplossing teenwoordig en die molekulêre struktuur van albei isomere is kristallografies bepaal. Dit is vasgestel dat al die kationiese komplekse in ’n effens verwronge vierkantvlakomgewing, met die karbeenligand byna loodreg op dié vlak, voorkom. Die metaal-karbeenbindingslengtes is onsensitief teenoor ’n variasie in die substituente gebind aan die karbeenligande en dit is nie ’n handige parameter om tussen die sterktes van dié bindings te differensieer nie. Die N-heterosikliese karbeenligande waarvan die N-atoom in ’n posisie drie bindings van die karbeenkoolstofatoom af voorkom, toon ’n effens sterker trans-invloed as die ligande met ’n α-stikstofatoom in die palladiumkomplekse. Dit is ’n aanduiding dat eersgenoemde ligande beter σ-donor eienskappe besit. Die nikkelkomplekse verskil egter nie betekenisvol ten opsigte van hul Ni-Cl bindingslengtes nie. Die katalitiese aktiwiteit en stabiliteit van die nuwe reekse palladium- en nikkelkomplekse is in Mizoroki-Heck en Suzuki-Miyaura-koppelingsreaksies ondersoek. Ofskoon relatief hoë temperature nodig is om koppeling te bewerkstellig en die komplekse nie koppeling van ’n arielchloried met butielakrilaat kataliseer nie, toon die palladiumkomplekse tóg potensiaal as prekatalisatore in die Mizoroki-Heck-reaksie. Die kompleks, trans-chloro(1,2-dimetiel-1,4- dihidrokinolien-4-ilideen)bis(trifenielfosfien)paladium(II) trifluorometaansulfonaat, toon ook uitstekende katalitiese aktiwiteit in die C,C-koppeling van bromofluoreen met arielboorsure in die Suzuki-Miyaura-koppelingsreaksie. Hierdie kompleks kataliseer selfs die koppeling van steries gehinderde arielhaliede met arielboorsure. Die kompleks trans-chloro(1,2-dimetiel- 1,4-dihidrokinolien-4-ilideen)bis(trifenielfosfien)nikkel(II) trifluorometaansulfonaat, bemiddel koppeling van arielbromied-, sowel as steries gehinderde arielchloriedsubstrate aan arielboorsure. Selfs beter resultate in die Mizoroki-Heck- sowel as die Suzuki-Miyaurakoppelingsreaksies word verwag deur verdere optimalisering van die reaksiekondisies en die inbouing van groter steriese hindering in die ligande.
Dunn, James A. "From organometallic cations to carbenes : an NMR, structural and reactivity study /". *McMaster only, 1998.
Znajdź pełny tekst źródłaRadzewich, Catherine Ellen. "Activation of small molecules by cationic rhenium complexes /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/11554.
Pełny tekst źródłaHaque, Rosenani S. M. Anwarul. "Silver, mercury and ruthenium complexes of N-heterocyclic carbene linked cyclophanes". University of Western Australia. Chemistry Discipline Group, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0236.
Pełny tekst źródłaStander-Grobler, Elzet. "Carbene ligand and complex design directed towards application in synthesis and homogeneous catalysis". Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1139.
Pełny tekst źródłaAlkylated acetonitrile that forms during the synthesis of the sulfonium salt, [(Me3)2(MeS)S][BF4], is involved in the formation of new , -unsaturated Fischer-type carbene complexes from (CO)5M=C(OMe)CH2Li (M = Cr, W). Metal migration observed when the substitution product obtained from the reaction of the anionic carbene complexes (CO)5M=C(NMe2)CºC¯ (M = Cr, W) with Ph3PAu+ was left in solution, was also kinetically and theoretically investigated. 1H NMR and quantum mechanical (at the B3LYP level of theory) data indicated a complicated mechanism. The a,b-unsaturated Fischer-type carbene complex, (CO)5Cr=C(OMe)CH=C(Me)NH(Me), obtained from the reaction of (CO)5M=C(OMe)CH2¯ with alkylated acetonitrile, was transformed into the new remote one-N, six-membered, carbene ligand (rN1HC6) complex, (CO)5Cr=C(CH=C(Me)N(Me)CH=C(nBu). The carbene ligand unprecedentedly preferred the softer Rh(CO)2Cl moiety to the Cr(CO)5 metal fragment and transferred readily. A new series of remote and abnormal square planar compounds [r/a(NHC)(PPh3)2MCl]CF3SO3 (M = Pd or Ni) was prepared by oxidative substitution. The various positions for metal-carbon bond formation on a pyridine ring to furnish various ligand types i.e. C2 for nN1HC6, C3 for aN1HC6 or C4 for rN1HC6 received attention. The ligands were arranged in increasing order of carbene character, aNHC < nNHC < rNHC and trans influence, nN2HC5 ~ aN1HC6 ~ nN1HC6 < rN1HC6. In competitive situations, oxidative substitution occurred selectively at C4 of the pyridine ring rather than at C2 and on the aromatic ring containing the heteroatom (C4), rather than on an annealed aromatic ring (C7). Crystal and molecular structure determinations confirmed the preferred coordination sites. Quantum mechanical calculations (at the RI-BP86/SV level of theory) indicated that the chosen carbene ligand has a much larger influence than the metal on the BDE of the M-Ccarbene bond; the farther away the N-atom is from the carbene carbon, the stronger the bond. In complexes that also contain additional external nitrogen atoms, e.g. trans-chloro(N-methyl-1,2,4- trihydro-2-dimethylaminepyrid-4-ylidene)bis(triphenylphosphine)palladium(II) triflate and transchloro( N-methyl-1,2,4-trihydro-2-dimethylaminepyrid-4-ylidene)bis(triphenylphosphine)nickel(II) triflate, stabilisation originates from both the nitrogens. 2-Chloro-1-methyl-1H-pyrid-4-ylidenephenylammonium triflate afforded complexes with both remote as well as normal nitrogen atoms. New azole complexes of palladium and nickel with remote heteroatoms were also prepared from N-methyl-4',4'-dimethyl-2'-thiophen-3-chloro-2-yl-4,5-dihydro-oxazole. Employing the compound 1,5-dichloroanthraquinone, the product of a double oxidative substitution on two Pd centra could be isolated but not alkylated. The fact that the chemical shift of the metal bonded carbon in the 13C NMR spectrum can not be used as absolute measure of carbene character, was emphasised in a compound where the heteroatom was situated seven bonds away from the carbon donor. In efforts to synthesise a sulphur-bridged complex that contains carbene ligands, crystals of transdi- iodobis(1,3-dimethyl-imidazoline-2-ylidene)palladium were obtained. Bridged thiolato complexes with N1HC6 ligands were unexpectedly found in the attempt to substitute the halogen on chosen square planar carbene complexes of palladium, widening the application possibilities of N1HC6 ligands in organometallic chemistry beyond that of catalysis. A trinuclear cluster, [(PdPPh3)3(μ-SMe)3]BF4 was isolated as a by-product of these reactions. A series normal and abnormal thiazolylidene complexes of nickel and palladium were prepared by oxidative substitution of the respective 2-, 4- and 5-bromothiazolium salts with M(PPh3)4 (M = Pd or Ni), and unequivocally characterised. In a preliminary catalytic investigation, all the thiazolinium and simple pyridinium derived palladium complexes showed activity in the Suzuki-Miyaura coupling reaction. Little variation in activity in the order a (N next to carbon donor) > n > a (S next to carbon donor) was found for the former series, whereas decreased activity was exhibited in the sequence r > a > n of the latter group. The pyridinium derived complexes showed superior activity to the thiazolinium ones. The rNHC complex, trans-chloro(N-methyl-1,2,4-trihydro-2- dimethylaminepyrid-4-ylidene)bis(triphenylphosphine)palladium(II) triflate, showed similar Suzuki-Miyaura activity to the standard N2HC5 carbene complex precatalyst, trans-chloro[(1,3- dimethyl-imidazol-2-ylidene)triphenylphosphine]palladium(II) triflate.
Julius, Gerrit R. "New transition metal carbene complexes for application in homogeneous catalysis". Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1391.
Pełny tekst źródłaThis study comprises the preparation and full characterisation of new carbene complexes of group 10 metals (Ni, Pd or Pt), the group 9 metal, rhodium, as well as group 6 metals (Cr and/or W). N-heterocyclic carbene (NHC) complexes of nickel and palladium were prepared via oxidative addition of the corresponding carbene precursors imidazolium-, imidazolinium-, pyridinium- and quinolinium chloride salts, to M(PPh3)4 (M = Ni or Pd). Three types of carbene complexes, namely the standard five-membered two-N carbene complexes, new six-membered NHC complexes and novel six-membered rNHC complexes received attention. In the rNHC complexes the heteroatom (N) is removed from the carbene carbon. These new square planar carbene complexes of the general formula trans-[(PPh3)2MCl(L)]X (M = Ni or Pd; X = BF4 or PF6) L = 1,3-dimethyl-2,3-dihydro-1Himidazol- 2-ylidene, 1,3-dimethyl-2,3,4,5-tetrahydro-1H-imidazol-2-ylidene, 1-methyl-1,2-dihydropyridin- 2-ylidene, 1-methyl-1,2-dihydro-quinolin-2-ylidene, 1,4-dimethyl-1,2-dihydro-quinolin-2- ylidene, 2-methoxy-1-methyl-1,4-dihydro-quinolin-4-ylidene, 1-methyl-1,4-dihydro-pyridin-4- ylidene) have been isolated and characterised. The preparation of the corresponding carbene complexes of platinum was complicated by the formation of [PtCl(PPh3)3]BF4 and the desired carbene complexes could not be isolated in pure form. The investigation of rNHC complexes was extended to include the synthesis of (CO)5M{CSC(CNCMe2CH2O)CHCH} (M = Cr and W). The molecular and crystal structures of thirteen of the new carbene complexes including the structures of both cis- (only formed below –20°C) and trans-chloro(1-methyl-1,2-dihydro-quinolin- 2-ylidene)bis(triphenylphosphine)palladium(II) tetrafluoroborate were determined. The metalcarbene bond distances in both the palladium and nickel carbene families do not differ significantly. The carbene ligands can be arranged in a series of increasing trans-influence, using the metalchloride bond distance as a guideline, as follows: 1,3-dimethyl-2,3-dihydro-1H-imidazol-2-ylidene and 1,3-dimethyl-2,3,4,5-tetrahydro-1H-imidazol-2-ylidene < 1-methyl-1,2-dihydro-pyridin-2- ylidene < 2-methoxy-1-methyl-1,4-dihydro-quinolin-4-ylidene, 1-methyl-1,4-dihydro-pyridin-4- ylidene. The crystal and molecular structures of two platinum compounds, cis-chloro(2-methoxy-1- methyl-1,4-dihydro-quinolin-4-ylidene)bis(triphenylphosphine)platinum(II) tetrafluoroborate and the byproduct [PtCl(PPh3)3]BF4 were also determined. Trans-chloro(2-methoxy-1-methyl-1,4-dihydro-quinolin-4-ylidene)bis(triphenylphosphine) palladium(II) tetrafluoroborate was found to be a very active catalyst, compared to simpler palladium carbene and phosphine complexes, in the Mizoroki-Heck and Suzuki-Miyaura coupling reactions. Quantum mechanical calculations indicated that the rNHC ligand in this complex is bound stronger to the palladium than a standard imidazole-derived NHC ligand. Further calculations suggested that the remote heteroatom carbene (rNHC) complexes of nickel(II) are significantly more stable when compared to the normal carbene (NHC) complexes. Energy decomposition analysis suggested that the rNHC ligands are strong s-donors and weak -acceptors. Unsymmetrical imidazolium-derived bis(carbene) complexes, [Rh(NHC)2COD]Br, bromomono( carbene) complexes, Rh(Br)COD(NHC), and chloro-mono(carbene) complexes, Rh(Cl)COD(NHC) where NHC = 1-R-3-methyl-2,3-dihydro-1H-imidazol-2-ylidene (R = ethyl, propyl or butyl), were formed in each reaction of the corresponding free carbene ligand with [Rh(Cl)COD]2. [Rh(Br)COD(NHC)] formed as a result of substitution of a chloride ligand by a Br-- anion. The carbonyl complexes, cis-[Rh(CO)2X(NHC)] (X = Br or Cl; NHC = 1-ethyl-3-methyl- 2,3-dihydro-1H-imidazol-2-ylidene) were isolated after the substitution of the COD ligand in Rh(X)COD(NHC) (X = Br or Cl) with CO. Isomerisation of these cis-carbonyl complexes to the trans isomers was observed. Cis-[(h4-1,5-cyclooctadiene)bis(1-butyl-3-methyl-2,3-dihydro-1H-imidazol-2-ylidene)rhodium(I)] bromide, bromo(h4-1,5-cyclooctadiene)(1-methyl-3-propyl-2,3-dihydro-1H-imidazol-2-ylidene) rhodium(I) and cis-[(h4-1,5-cyclooctadiene)bis(1-butyl-3-methyl-2,3-dihydro-1H-imidazol-2- ylidene)rhodium(I)]bromide were also characterised by single crystal X-ray diffraction. The synthesis and structural characterisation of a series of acyclic and heterometallacyclic Fischertype carbene complexes in which a soft donor atom (P) attached to the carbene side chain is either uncoordinated, (CO)5M=C(NMe2)CH2PPh2 (M = Cr or W), bonded to the original central metals (Cr or W) in four-membered chelates, (CO)4M=C(NMe2)CH2PPh2, or coordinated to a second M(CO)5 unit (only isolated for chromium) (CO)5Cr=C(NMe2)CH2P(Ph2)Cr(CO)5, were carried out. These compounds were produced by the reaction of the anionic Fischer-type aminocarbene complexes, [(CO)5Cr=C(NMe2)CH2]Li (M = Cr or W), with ClPPh2. The formation of the four-membered chelates, via cyclisation, occurs much faster for Cr than for W. The aminocarbene-phosphine chelates represent the first examples of structurally characterised, four-membered C,P-chelate carbene complexes.
Kuchenbeiser, Glenn Richard. "Reactivity of bis(amino)cyclopropenylidenes (BACs) and cyclic (alkyl)(amino)carbenes (CAACs) coordination chemistry, catalysis, and small molecule activation /". Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1899480521&SrchMode=2&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269286714&clientId=48051.
Pełny tekst źródłaIncludes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 10, 2010). Includes bibliographical references. Also issued in print.
Santoro, Orlando. "Copper(I)-N-heterocyclic carbene (NHC) complexes : synthesis, characterisation and applications in synthesis and catalysis". Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8409.
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