نتایج جستجو برای: lone pair

تعداد نتایج: 121561  

Journal: :Chemical communications 2005
Manab Chakravarty Praveen Kommana K C Kumara Swamy

Non-stoichiometry and isostructurality in a set of chiral phosphorus compounds as a result of lone pair/oxygen exchange, substantiated by the combined use of 31P NMR spectroscopy and X-ray crystallography, is described.

2016
Dulal C. Ghosh Sandip Kumar Rajak

In this chapter, Ghosh and Rajak have made a detailed quantum mechanical study of the variation of the dipole moment of ammonia as a function of its conformations evolving during the process of its umbrella inversion by invoking their method of dipole correlation of electronic structure as basis. Ghosh et al discover a surprising result that the variation of dipole moment mimics the total energ...

Journal: :Angewandte Chemie 2003
Michael A T Maughan Ieuan G Davies Timothy D W Claridge Steve Courtney Phil Hay Benjamin G Davis

Although amine nitrogen atoms are potential stereogenic centers, their configurational lability arising from lone-pair inversion has typically prevented their utility in synthesis.NHalogenation can dramatically slow lone-pair inversion and therefore raise the temperature at which the configurational lability ceases. We therefore considered that if a suitable system could be found, N-chloramines...

Journal: :Organic & biomolecular chemistry 2005
Paul G Loncke Gilles H Peslherbe

Substituent effects and the role of negative hyperconjugation in 1,2-silyl migration and decarbonylation of methoxy(substituted-siloxy)carbenes have been investigated using quantum chemical calculations and natural bond orbital analysis. It has been found that sigma-electron-withdrawing substituents generally lower the barriers for 1,2-silyl migration and decarbonylation, consistent with symmet...

Journal: :Dalton transactions 2007
Matthew Chen J Robin Fulton Peter B Hitchcock Nick C Johnstone Michael F Lappert Andrey V Protchenko

A series of beta-diketiminate lead halide complexes has been synthesised LPbCl (2), LPbBr (3) and LPbI (4) (L = {N(2,6-(i)Pr(2)C(6)H(3))C(Me)}2CH]), which includes a rare example of a three-coordinate lead iodide (4). The chloride and bromide complexes, 2 and 3, are relatively stable in both the solid and solution states, only slowly decomposing to elemental lead over the course of a month in s...

Journal: :Physical chemistry chemical physics : PCCP 2015
Zahra Badri Cina Foroutan-Nejad Jiri Kozelka Radek Marek

In the present work the nature of lone-pair-π interactions between water molecules and a number of π-rings with different substituents/hetero-atoms in the light of quantum chemical topology approaches is studied. The Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA) were employed for distinguishing the role of heteroatoms and electron withdrawing substituents in t...

2012
Gerhard Raabe Wolfgang Karl Dieter Enders Jörg Fleischhauer

X-ray structure determination of the enamine (Z)-4-(6'-t-butoxycarbonyl-2',2'-dimethyl-5'-phenyl3'-hexen-3'-yl)morpholine (1) reveals that certain bulky groups may enforce a relative orientation of the molecular subunits without conjugative interaction between the nitrogen lone pair and the olefinic double bond. According to the results of quantum chemical ab initio calculations the experimenta...

DFT-GGA method of Perdew-Burke-Ernzerhof (PBE) is used with aug-cc-PVTZ, 6-311++G**, and Def2-TZVP large basis sets to study the hydrogen bond interactions between oxygen lone pair as a donor electron with hydrogen atom connected to the aniline’s nitrogen as an electron acceptor (H2O···HNH-Ph), and nitrogen lone pair with hydrogen of water molecule (Ph-H2N···HOH...

Journal: :Chemical communications 2013
Elli Chatzopoulou Paul W Davies

A robust N-nucleophilic 1,3-N,O-dipole equivalent reacts with unsymmetrical internal alkynes under gold catalysis. Conjugation from a remote nitrogen lone pair enables and controls this convergent and highly regioselective process.

Journal: :Chemical communications 2012
De-Xian Wang Shi-Xin Fa Yang Liu Bao-Yong Hou Mei-Xiang Wang

Chloride-π interaction along with lone-pair electrons-π interaction, hydrogen bonding and π-π stacking induced the hexameric assembly of the parent macrocycle into a rectangular supramolecular cage in the solid state.

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