Experimental observation of relativistic effects on electronic wavefunction for iodine lone-pair orbital of CF3I

The low-lying candidates of hydrated divalent lead ion clusters [ Pb(H2O) n]2+ with up to n = 17 have been extensively studied by using density functional theory (DFT) at B3LYP level. The optimized structures show that for n = 5–13 the lowest-energy structures prefer tetracoordinate with hemi-directed geometries, while the best candidates with n = 14–17 are hexacoordinate with holo-directed geometries, which is just consistent with the experimental observation. Furthermore, the origin of hemi-directed and holo-directed geometries has been revealed. It is found that in the hemi-directed geometries, the lone pair orbital has p character and fewer electrons are transferred from the water molecules to the Pb2+ ion. Contrarily, in the holo-directed geometries, the lone pair orbital has little or no p character and more electrons are transferred to the Pb2+ ion. On the other hand, the proton transfer reactions of the [ Pb(H2O) n]2+(n = 2, 4, 8) complexes have been examined, from which the predicted products of these complexes are in good agreement with the experimental observation.

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Amino group stretching vibrations in primary aliphatic amines

Canadian Journal of Chemistry ◽

10.1139/v67-262 ◽

1967 ◽

Vol 45 (14) ◽

pp. 1605-1610 ◽

Cited By ~ 17

Author(s):

P. J. Krueger ◽

D. W. Smith

Keyword(s):

Alkyl Chain ◽

Inductive Effect ◽

Lone Pair ◽

Aliphatic Amines ◽

Lone Pair Orbital ◽

First Approximation ◽

Symmetric Band ◽

Integrated Intensity ◽

Stretching Vibrations ◽

Primary Aliphatic Amines

Primary aliphatic amines can be characterized by infrared spectroscopy as to the nature and degree of branching of the alkyl chain, using the fundamental antisymmetric and symmetric NH2 stretching frequencies measured in dilute C2Cl4 solution. Where steric and direct conjugation effects are absent both frequencies and the integrated intensity of the antisymmetric band increase linearly with decreasing inductive electron-donating power of the alkyl chain. The integrated intensity of the symmetric band, which is smaller than that for the antisymmetric band in all the 26 compounds studied, is independent of the inductive nature of the alkyl chain as a first approximation. These results indicate that the N-atom lone-pair orbital in RNH2 plays a negligibly small role in modifying the inductive effect of R on NH2 frequencies and intensities as long as the N-atom hybridization remains sp3.

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A G2(MP2) theoretical study of substituent effects on H3BNHnCl3−n (n= 3-0) donor-acceptor complexes

Open Chemistry ◽

10.2478/s11532-008-0029-0 ◽

2008 ◽

Vol 6 (3) ◽

pp. 400-403 ◽

Cited By ~ 5

Author(s):

Hafid Anane ◽

Soufiane Houssame ◽

Abdelali Guerraze ◽

Abdeladim Guermoune ◽

Abderrahim Boutalib ◽

...

Keyword(s):

Theoretical Study ◽

Substituent Effects ◽

Lone Pair ◽

Proton Affinities ◽

Lone Pair Orbital ◽

Chlorine Substitution ◽

Donor Acceptor ◽

Nitrogen Lone Pair ◽

The Stability ◽

N Compounds

AbstractThe complexation energies of H3BNHnCl3−n (n= 3-0) complexes and the proton affinities of NHnCl3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution on the ammonia decreases both the basicity of the NHnCl3−n ligands and the stability of H3BNHnCl3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character in these bonds.

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