Journal articles on the topic 'Hammond’s postulate'

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1

Carreón-Macedo, José-Luis, Jeremy N. Harvey, and Rinaldo Poli. "The Reductive Elimination of Methane fromansa-Hydrido(methyl)metallocenes of Molybdenum and Tungsten: Application of Hammond’s Postulate to Two-State Reactions." European Journal of Inorganic Chemistry 2005, no. 15 (August 2005): 2999–3008. http://dx.doi.org/10.1002/ejic.200500236.

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2

YARNELL, AMANDA. "HAMMOND POSTULATE." Chemical & Engineering News Archive 81, no. 20 (May 19, 2003): 42. http://dx.doi.org/10.1021/cen-v081n020.p042.

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3

Petersson, G. A., T. G. Tensfeldt, and J. A. Montgomery. "Vinylidene and the Hammond postulate." Journal of the American Chemical Society 114, no. 15 (July 1992): 6133–38. http://dx.doi.org/10.1021/ja00041a034.

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4

Nalewajski, Roman F., and Elżbieta Broniatowska. "Information distance approach to Hammond postulate." Chemical Physics Letters 376, no. 1-2 (July 2003): 33–39. http://dx.doi.org/10.1016/s0009-2614(03)00915-1.

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5

Denisov, E. T. "The Hammond postulate: A quantitative interpretation." Russian Journal of Physical Chemistry B 2, no. 3 (June 2008): 343–49. http://dx.doi.org/10.1134/s1990793108030020.

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6

Cremer, Dieter, and Elfi Kraka. "Verification and Quantification of the Hammond-Leffler Postulate." Revista Processos Químicos 6, no. 11 (January 2, 2012): 27–30. http://dx.doi.org/10.19142/rpq.v6i11.152.

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O postulado de Hammond-Leffl er prevê que reações exotérmicas possuem estados de transições (ET) mais similares a estrutura dos reagentes e as reações endotérmicas mais similares aos produtos. Nós mostramos que esta previsão pode ser verifi cada calculandose a trajetória de reação e a sua curvatura utilizando métodos de química quântica. A trajetória escalar da curvatura adota o ponto máximo da reação onde há a quebra e a formação de ligações durante o processo químico. É sempre possível defi nir o centro da área desta trajetória. A mudança do ET em relação a este centro muda linearmente com a energia da reação de valores positivos (reações exotérmicas) a valores negativos (reações endotérmicas) descrevendo assim quantitativamente o caráter do ET como sendo similar aos reagentes ou produtos.
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7

Scala, Alfred A. "Free Radical Halogenation, Selectivity, and Thermodynamics: The Polanyi Principle and Hammond's Postulate." Journal of Chemical Education 81, no. 11 (November 2004): 1661. http://dx.doi.org/10.1021/ed081p1661.

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8

Meany, J. E., Vicky Minderhout, and Y. Pocker. "Application of Hammond's Postulate. An Activity for Guided Discovery Learning in Organic Chemistry." Journal of Chemical Education 78, no. 2 (February 2001): 204. http://dx.doi.org/10.1021/ed078p204.

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9

Ponec, Robert, Gleb Yuzhakov, and Jaroslav Pecka. "Similarity approach to chemical reactivity. Theoretical justification of the Hammond postulate." Journal of Mathematical Chemistry 19, no. 3 (1996): 265–70. http://dx.doi.org/10.1007/bf01166718.

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10

Arteca, Gustavo A., and O. Tapia. "Generalized electronic diabatic approach to structural similarity and the Hammond postulate." International Journal of Quantum Chemistry 107, no. 2 (September 5, 2006): 382–95. http://dx.doi.org/10.1002/qua.21157.

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11

Majumdar, D., S. P. Bhattacharyya, and D. K. Maity. "Local Hammond postulate and a local model for monitoring reaction paths." International Journal of Quantum Chemistry 43, no. 4 (July 30, 1992): 567–72. http://dx.doi.org/10.1002/qua.560430408.

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12

Cioslowski, Jerzy. "Quantifying the Hammond postulate: intramolecular proton transfer in substituted hydrogen catecholate anions." Journal of the American Chemical Society 113, no. 18 (August 1991): 6756–60. http://dx.doi.org/10.1021/ja00018a006.

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13

Arteca, Gustavo A., and Paul G. Mezey. "Validity of the Hammond postulate and constraints on general one-dimensional reaction barriers." Journal of Computational Chemistry 9, no. 7 (October 1988): 728–44. http://dx.doi.org/10.1002/jcc.540090704.

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14

Jursic, Branko S. "AM1 semiempirical study of benzopyrroles as dienes for Diels-Alder reaction." Canadian Journal of Chemistry 74, no. 1 (January 1, 1996): 114–20. http://dx.doi.org/10.1139/v96-015.

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A qualitative approach for quick evaluation of the reactivity of dienes such as cyclopentadiene, furan, pyrrole, indole, and isoindole for Diels–Alder reactions was applied. As qualitative methods, the frontier molecular orbital (FMO) energy gap and the Hammond postulate through bond orders and energy of the reaction were evaluated for such dienophiles as ethylene, 1,3-dioxa-4-cyclopentene, and maleic anhydride. It was demonstrated that pyrrole and benzopyrroles are poor dienes in comparison with cyclopentadiene and furan. Because the reaction is controlled by the HOMO of the diene there are special cases when isoindole can react as a diene, while the loss of indole aromaticity in the course of the reaction precludes the cycloaddition. Geometries of transition structures and the accompanying activation energies were calculated for pyrrole, indole, and isoindole as dienes. The stereoselectivity of the reaction is discussed and compared with experimental results. Key words: benzopyrroles as dienes, Diels–Alder cycloaddition, Hammond postulate.
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15

Solà, Miquel, and Alejandro Toro-Labbé. "The Hammond Postulate and the Principle of Maximum Hardness in Some Intramolecular Rearrangement Reactions." Journal of Physical Chemistry A 103, no. 44 (November 1999): 8847–52. http://dx.doi.org/10.1021/jp990576e.

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16

Bulat, Felipe A., and Alejandro Toro-Labbé. "An Extension of the Hammond Postulate. Structural Effects on the Classification of Chemical Reactions." Journal of Physical Chemistry A 107, no. 19 (May 2003): 3987–94. http://dx.doi.org/10.1021/jp022025l.

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17

Sartin, Loleta D., and Vicki Luther. "University-School Partnerships: A True Story of How They Work and Who They Help." Georgia Journal of Literacy 32, no. 2 (October 30, 2009): 9–14. http://dx.doi.org/10.56887/galiteracy.81.

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University researchers are calling for partnerships as a way to improve PK-12 schools and their own teacher education and school policy research (Via, 2008). Amongst the approximate 107,235 people graduating with a degree in education, many are in need of additional support and best practice acquisition (NCES, 2007; Darling-Hammond, 2000). Henderson, Mapp, Johnson, and Davies (2007), in their book Beyond the Bake Sale, postulate that partnerships and student achievement are closely linked.
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18

Rajendran, Kamalraj V., Kirill V. Nikitin, and Declan G. Gilheany. "Hammond Postulate Mirroring Enables Enantiomeric Enrichment of Phosphorus Compounds via Two Thermodynamically Interconnected Sequential Stereoselective Processes." Journal of the American Chemical Society 137, no. 29 (July 17, 2015): 9375–81. http://dx.doi.org/10.1021/jacs.5b04415.

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19

Haddon, Robert C., Ziqi Tian, and De-en Jiang. "Comparative Reaction Diagrams for the SN2 Reaction Formulated According to the Leffler Analysis and the Hammond Postulate." Journal of Organic Chemistry 81, no. 9 (April 11, 2016): 3648–53. http://dx.doi.org/10.1021/acs.joc.6b00298.

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20

Arteca, Gustavo A., and Paul G. Mezey. "Molecular similarity and molecular shape changes along reaction paths: a topological analysis and consequences on the Hammond postulate." Journal of Physical Chemistry 93, no. 12 (June 1989): 4746–51. http://dx.doi.org/10.1021/j100349a014.

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21

Lopez, Xabier, Annick Dejaegere, and Martin Karplus. "Solvent Effects on the Reaction Coordinate of the Hydrolysis of Phosphates and Sulfates: Application of Hammond and Anti-Hammond Postulates to Understand Hydrolysis in Solution." Journal of the American Chemical Society 123, no. 47 (November 2001): 11755–63. http://dx.doi.org/10.1021/ja010683y.

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22

Matouschek, A., and A. R. Fersht. "Application of physical organic chemistry to engineered mutants of proteins: Hammond postulate behavior in the transition state of protein folding." Proceedings of the National Academy of Sciences 90, no. 16 (August 15, 1993): 7814–18. http://dx.doi.org/10.1073/pnas.90.16.7814.

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23

Donahue, Neil M. "Revisiting the Hammond Postulate: The Role of Reactant and Product Ionic States in Regulating Barrier Heights, Locations, and Transition State Frequencies†." Journal of Physical Chemistry A 105, no. 9 (March 2001): 1489–97. http://dx.doi.org/10.1021/jp001004t.

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24

Ponec, Robert. "Molecular Basis of LFER. Simple Model for the Estimation of Brønsted Exponent in Acid-Base Catalysis." Collection of Czechoslovak Chemical Communications 69, no. 12 (2004): 2121–33. http://dx.doi.org/10.1135/cccc20042121.

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A simple model was proposed allowing to estimate the Brønsted exponents in acid-base catalysis on the basis of the pK values of the species participating in the proton transfer process. The approach was tested using the experimental data on the basically catalyzed halogenation of carbonyl compounds and on the proton removal from nitroalkanes. It has been shown that the model is able to reproduce the Brønsted exponents not only in the case of "ordinary" Brønsted plots with the slope within the expected range 0-1 but also for unusual plots with negative slopes. In addition, the proposed model opens the possibility of calculation of the activation energies of a given proton transfer reaction and also provides straightforward theoretical justification for the validity of the Hammond postulate in these reactions.
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25

Kim, Sung Soo, Hong Rae Kim, Hong Bae Kim, Sang Jun Youn, and Chul Jae Kim. "Homolytic Fragmentations of Benzyl Methyl Substituted-Benzyl Carbinyloxy Radicals and Related Reactions: Limitations of the Leffler-Hammond Postulate and the Reactivity/Selectivity Principle." Journal of the American Chemical Society 116, no. 7 (April 1994): 2754–58. http://dx.doi.org/10.1021/ja00086a008.

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26

Rico-Pasto, Marc, Annamaria Zaltron, and Felix Ritort. "Force Dependence of Proteins’ Transition State Position and the Bell–Evans Model." Nanomaterials 11, no. 11 (November 11, 2021): 3023. http://dx.doi.org/10.3390/nano11113023.

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Single-molecule force spectroscopy has opened a new field of research in molecular biophysics and biochemistry. Pulling experiments on individual proteins permit us to monitor conformational transitions with high temporal resolution and measure their free energy landscape. The force–extension curves of single proteins often present large hysteresis, with unfolding forces that are higher than refolding ones. Therefore, the high energy of the transition state (TS) in these molecules precludes kinetic rates measurements in equilibrium hopping experiments. In irreversible pulling experiments, force-dependent kinetic rates measurements show a systematic discrepancy between the sum of the folding and unfolding TS distances derived by the kinetic Bell–Evans model and the full molecular extension predicted by elastic models. Here, we show that this discrepancy originates from the force-induced movement of TS. Specifically, we investigate the highly kinetically stable protein barnase, using pulling experiments and the Bell–Evans model to characterize the position of its kinetic barrier. Experimental results show that while the TS stays at a roughly constant distance relative to the native state, it shifts with force relative to the unfolded state. Interestingly, a conversion of the protein extension into amino acid units shows that the TS position follows the Leffler–Hammond postulate: the higher the force, the lower the number of unzipped amino acids relative to the native state. The results are compared with the quasi-reversible unfolding–folding of a short DNA hairpin.
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27

Nalewajski, Roman F. "Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective." Applied Sciences 9, no. 6 (March 26, 2019): 1262. http://dx.doi.org/10.3390/app9061262.

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Several applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradient information. Continuities of molecular probability and current distributions, reflecting the modulus and phase components of molecular wavefunctions, respectively, are summarized. Resultant measures of the entropy/information descriptors of electronic states, combining the classical (probability) and nonclassical (phase/current) contributions, are introduced, and information production in quantum states is shown to be of a nonclassical origin. Importance of resultant information descriptors for distinguishing the bonded (entangled) and nonbonded (disentangled) states of reactants in acid(A)–base(B) systems is stressed and generalized entropy concepts are used to determine the phase equilibria in molecular systems. The grand-canonical principles for the minima of electronic energy and overall gradient information allow one to explore relations between energetic and information criteria of chemical reactivity in open molecules. The populational derivatives of electronic energy and resultant gradient information give identical predictions of electronic flows between reactants. The role of electronic kinetic energy (resultant gradient information) in chemical-bond formation is examined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and changes of the overall structure information in chemical processes are addressed. The frontier-electron basis of the hard (soft) acids and bases (HSAB) principle is reexamined and covalent/ionic characters of the intra- and inter-reactant communications in donor-acceptor systems are explored. The complementary A–B coordination is compared with its regional HSAB analog, and polarizational/relaxational flows in such reactive systems are explored.
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28

Thomas, Lawrence J., Laura A. Vitale, Michael Murphy, Collin Xia, Zeyu Peng, Asma Ejas, Montu Patel, et al. "Abstract 2963: CDX-585, a novel bispecific antibody targeting PD-1 and ILT4." Cancer Research 83, no. 7_Supplement (April 4, 2023): 2963. http://dx.doi.org/10.1158/1538-7445.am2023-2963.

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Abstract Both PD-1 and ILT4 (LILRB2, CD85d) have well established immunosuppressive effects that enable tumors to evade anti-tumor immunity. Tumor expression of PD-L1 and ILT4 has been associated with poor clinical outcomes in several cancer types. Recently, ILT4 activation has been postulated as a resistance mechanism for PD-1/PD-L1 blockade prompting the investigation of dual blockade of these pathways. Siu, L.L. et al. (2022 Clin Cancer Res 28: 57-70) reported encouraging results of the initial clinical study combining the ILT4 antagonist mAb MK-4830 with pembrolizumab. The combination was generally well tolerated and led to several durable responses including in PD-1/PD-L1 refractory patients. We have combined novel PD-1 (mAb E1A9) and ILT4 (mAb 7B1) antagonist antibodies into a tetravalent IgG-scFv format bispecific antibody (bsAb, CDX-585). CDX-585 was engineered to avoid effector functionality by eliminating interaction with Fcγ receptors, and to increase its half-life by enhancing binding to FcRn. As expected, CDX-585 inhibits interaction of PD-1 and ILT4 with their ligands, results in potent inhibition of PD-1 signaling and enhances myeloid cell inflammatory responses to stimulation through toll like receptors (LPS) or CD40 (CD40 agonist mAb). In mixed lymphocyte reactions CDX-585 promoted greater T cell activation than the combination of the parental mAbs. Similarly, CDX-585 demonstrated superior anti-tumor activity over the combination of the parental mAbs in a humanized mouse model of melanoma. CDX-585 has completed GMP manufacturing and IND-enabling activities. Doses of CDX-585 up to 60 mg/kg were well tolerated in cynomolgus macaques and displayed a favorable pharmacokinetic profile. Together these data demonstrate that CDX-585 effectively combines PD-1 and ILT4 blockade into one molecule with favorable biophysical and functional characteristics supporting the initiation of a dose-escalation clinical trial in patients with advanced solid tumors. Citation Format: Lawrence J. Thomas, Laura A. Vitale, Michael Murphy, Collin Xia, Zeyu Peng, Asma Ejas, Montu Patel, James Boyer, April R. Baronas, Thomas O'Neill, Jenifer Widger, Laura Mills-Chen, Andrea Crocker, Mark Ma, Mingjiu Chen, Hugh M. Davis, Russ A. Hammond, Cherie Taglienti, Michael Yellin, Joel Goldstein, Diego Alvarado, Henry C. Marsh, Tibor Keler. CDX-585, a novel bispecific antibody targeting PD-1 and ILT4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2963.
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29

Bochet, Christian G., and Freya M. Harvey. "Is there a photochemical Hammond postulate?" Chemical Science, 2021. http://dx.doi.org/10.1039/d0sc04370b.

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30

Mayr, Herbert, and Armin R. Ofial. "When Does Hammond's Postulate Predict Stabilities of Carbocations?" Israel Journal of Chemistry, May 3, 2023. http://dx.doi.org/10.1002/ijch.202300054.

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31

Cammi, Roberto, and Bo Chen. "Studying and exploring potential energy surfaces of compressed molecules: a fresh theory from the eXtreme Pressure Polarizable Continuum Model." Journal of Chemical Physics, August 23, 2022. http://dx.doi.org/10.1063/5.0104269.

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We present a new theory for studying and exploring the potential energy surface of compressed molecular systems as described within the XP-PCM framework. The effective potential energy surface is defined by the sum of the electronic energy of the compressed system and the pressure-volume work that is necessary in order to create the compression cavity at the given condition of pressure. We show that the resulting total energy Gt is related to the electronic energy by a Legendre transform, in which the pressure and volume of the compression cavity are the conjugate variables. We present an analytical expression for the evaluation of the gradient of the total energy ∇Gt to be used for the geometry optimization of equilibrium geometries and transition states of compressed molecular systems. We also show that, as a result of the Legendre transform property, the potential energy surface can be studied explicitly as function of the pressure, leading to an explicit connection with the well-known Hammond postulate. As a proof of concept, we present the application of the theory to studying and determining of the optimized geometry of compressed methane and the transition state of electrocyclic ring-closure of hexatriene and of H-transfer between two methyl radicals.
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