نتایج جستجو برای: electrophilicity
تعداد نتایج: 386 فیلتر نتایج به سال:
A series of homo- and hetero-tri(aryl)boranes incorporating pentafluorophenyl, 3,5-bis(trifluoromethyl)phenyl, and pentachlorophenyl groups, four of which are novel species, have been studied as the acidic component of frustrated Lewis pairs for the heterolytic cleavage of H2. Under mild conditions eight of these will cleave H2; the rate of cleavage depending on both the electrophilicity of the...
Acetalization of benzaldehyde and substituted benzaldehydes (containing both electron-donating and electron-withdrawing groups) is explained qualitatively on the basis of global electrophilicity descriptor, w, as proposed by Parr and coworkers. The generated values of w can explain qualitatively the preferential electrophilic addition, and hence, the yield of acetalization obtained in an earlie...
chemical hardness (), absolute electronegativity (), and electrophilicity () have importantapplications in inorganic chemistry. these concepts are defined quantitatively as � � �� � ����,� � �� � ����, � � ������where i is the ionization energy and a is the electron affinity. in thisstudy, graphical method was used to see the relation of electron configuration with chemicalhardness, absolute...
in this research at the first, captopril drug (ca) and its fullerene connected form (fca) wereoptimized. natural bond orbital (nbo) calculations for these compounds were carried out at theb3lyp/6-31g quantum chemistry level, in the gas phase and the liquid phase. these calculations canbe performed at different accuracy levels depending on the aim of the theoretical study [1]. forinstance, densi...
The size-dependence of different local reactivity descriptors of dimer A2 and AB type of systems is discussed. We derive analytic results of these descriptors calculated using finite difference approximation. In particular, we studied Fukui functions, relative electrophilicity and relative nucleophilicity, local softness and local philicity. The results are explained using the example of the di...
Quantum calculations of the physical properties (electronic and vibrational), based on density functional theory (DFT) method at B3LYP/6-31G** level of theory, were performed, by means of the Gaussian 09 set of programs, to investigate the effect of the addition of the radical CN on pyridazine molecules. The best geometry, the total energy, frontier molecular orbital energies (HOMO and HUMO), e...
Carbonyl-carbonyl (C=O···C'=O') interactions are ubiquitous in both small and large molecular systems. This interaction involves delocalization of a lone pair (n) of a donor oxygen into the antibonding orbital (π*) of an acceptor carbonyl group. Analyses of high-resolution protein structures suggest that these carbonyl-carbonyl interactions prefer to occur in pairs, that is, one donor per accep...
The addition of AlCl3 to four-coordinate boranes of the general formula (C-N-chelate)BCl2 results in halide abstraction and formation of three-coordinate borenium cations of the general formula [(C-N-chelate)BCl]+. The latter react with both arylstannanes and arylsilanes by boro-destannylation and -desilylation, respectively, to form arylated boranes. Catalytic quantities of AlCl3 were sufficie...
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