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Showing 1 to 20 of 21 for “"Substituent groups"”.
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Substituent Effects: A Computational Study on Stabilities of Cumulenes and Low Barrier Hydrogen Bonds
The effect of substituents on the stabilities of cumulenes-ketenes, allenes, diazomethanes and isocyanates and related systems-alkynes, nitriles and nitrile oxides is studied using the density functional theory (B3LYP, SVWN and BP86) and ab initio (HF, MP2) calculations at the 6-31G* basis set …
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Rates of acidic hydrolysis of triptych boroxazolidines
… some general trends as to the influence of the substituent groups on the values of the rate constants. If the rate constants of the reaction are considered at a fixed temperature, the rates of reaction in Group I decrease as the substituent is gradually changed from methyl to isopropyl. As soon …
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The effect of fluorination on the surface chemistry of adsorbate-metal systems
… techniques are used to determine the effect of substituents (mainly fluorine) on the surface chemistry of several adsorbate-metal systems. In the first system, the effect of two substituent groups ($-$CH$\sb3$ and $-$F) on the kinetics of the phenyl coupling reaction on the Cu(111) surface has …
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Inclusion compounds of multipedal hosts
… a planar electron-rich central region with bulky substituent groups attached to it. Each substituent contains a hydroxyl group capable of hydrogen bonding. These features enable the inclusion of small organic solvent molecules, with suitable functional groups, within the host framework. The …
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A Comparison of Reactivities and Properties of 3,3-Dimethylacrylic Acid, Isovaleric Acid and Their Derivatives
… than their unsaturated analogs. The size of the substituent groups in both amides and esters was varied in order to determine steric effects on reactivity of the systems.
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The synthesis and examination of Azo dyes derived from novel couplers
… or heterocyclic residue, often containing substituent groups. Results are interpreted in terms of the effect of Ar and Y. (electronic and steric) on the conjugation of the lone pair of electrons of the terminal nitrogen atom with the rest of the system. Thus, -the pyrrolidinoazo dyes …
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The kinetics of hydrolysis and the electronic absorption spectra of some sterically hindered basic dyes
… sulphur, nitrdgen or oxygen containing groups have been synthesised. Their absorption spectra have been measured in 98% acetic acid solution and compared with that of Malachite Green. The variations in Amax and E max for both the Xand y-band absorbances have been explained in terms of …
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Synthesis and Structure-property Evaluation of Novel Cellulosic Polymers as Amorphous Solid Dispersion Matrices for Enhanced Oral Drug Delivery
… to relatively rigid structures and bulky substituent groups, cellulose derivatives were more significant crystallization inhibitors compared to the synthetic polymers. The effective cellulose omega-carboxyesters were identified as possessing a similar hydrophobicity to the drug molecule …
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Novel Methods For The Analysis Of Organometallic compounds For The Natural Environment
… dependant upon the number and nature of organic substituent groups in the organometallic molecule. Speciation of organometallic compounds within environmental matrices therefore continues to be of great importance. There is a need for rapid and practical methods of analysis for organometallic …
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Studies on the Phospho-Aldol Reaction Catalysed by Aluminium Salcyan and Related Complexes
… the PA reaction. Through the manipulation of the substituent groups of the salcyan ligands there is the possibility of controlling the enantioselectivity and stereochemical outcome of the reaction. This thesis describes previous work that has been carried out with regards to the PA reaction, how …
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Quantum mechanical study of molecular switches : electronic structure, kinetics and dynamical aspects
… by the type, number and positioning of various substituent groups, systematic changes on activation energies and rates for the thermal cis-to-trans isomerization can be enforced. The nature of the transition state for ground state isomerization was investigated. Applying Eyring's transition …
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The Influence of Incorporated Cholesterol Auto-Oxides Upon The Permeability and Fluidity of Multilamellar Vesicles (Oxidized Sterols)
… vesicles to determine if the addition of a polar substituent group to the sterol molecule had an effect on the permeability and fluidity of these model membrane systems. An additional goal was to determine whether or not the polar substituent groups altered the orientation of the sterol molecule …
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Luminescent Iridium(III) Cyclometalated Complexes: Host-Guest Chemistry and Application as Sensors
… one polypyridine ligand (bpy=2,2 -bipyridine). Substituent groups R included: R=H (Ir-H); R=CHO (Ir-CHO); R=CH2NH-Bu, Bu=n-butylamine, (Ir-CH2NH-Bu); R=CH2NH-Oct, Oct=n-octylamine (Ir-CH2NH-Oct); and R=CH2N-(Oct)2 (Ir-CH2N-(Oct)2). Chapter 2 demonstrated that the R group in the iridium(III) …
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A structural systematic study of three families of salicyclic acid derivatives
… ability of particular complementary functional groups to form additional cohesive directional interactions. Depending on the system considered, each of these factors can have a more pronounced influence in determining the crystal packing. In order to develop a successful strategy to design new …
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Targeting ALS: A Multi-Cellular Study on the Potential Therapeutic Role of Azole-Based Compounds
… to better understand the impact of different substituent groups and azolium types on the salts' therapeutic potential.</p> <p>Chapter 5 discusses the broader implications of these findings for future research and therapeutic development. It highlights how these novel azolium salts could …
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Synthesis And Characterization Of Group 5 Metal Complexes Containing Pyrazolate, Amidate, And Related Ligands As Potential Precursors For Thin Film Growth By Atomic Layer Deposition
… and Nb(IV) amidate compounds with a variety of substituent groups were synthesized and structurally characterized. All the compounds are monomeric and isolated by sublimation at temperatures between 110-160 C/0.05 Torr. Several compounds were crystallized in solution and X-ray crystal …
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A study of the solution photophysics of the isomeric aminobenzoic acids, N, N-dimethylaminobenzoic acids and their methyl esters
… was obtained when the amino or N,N-dimethylamino substituent was in the meta- position relative to the carboxylic add or ester function. The amino compounds absorb with a peak between 300 and 325 nm depending on solvent, their fluorescence peaks lie between 350 and 410 rim. The corresponding …
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Novel Carbazole Based Methacrylates, Acrylates, and Dimethacrylates to Produce High Refractive Index Polymers
… carbazole, along with other aromatic substituents, into methacrylates, acrylates, and dimethacrylates. Subsequent free radical polymerizations provided for high refractive index materials well suited for lightweight optical spectacles and other applications. The refractive index of …
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