Charge distribution from infrared intensities: Which CH bonds form hydrogen bonds?

It is shown that one of the main reasons for most failures of the methods for calculating distance-dependent bond strengths is related to the distortion of the coordination polyhedra. The charge distribution (CD) method which depends on only one universal empirical parameter (contraction parameter) is modified to include: (i) an iterative calculation of the effective coordination number (ECoN), to deal with structures containing very distorted coordination polyhedra; (ii) a specific contraction parameter to treat structures containing any type of hydrogen bond; (iii) scale factors for coordination subshells, to treat structures with hetero-ligand polyhedra. The contraction parameter for the hydrogen bonds was obtained from 119 well refined structures based on neutron diffraction data. Examples of the application of the iterative charge distribution (CD-IT) are presented to show the efficiency of the new method in dealing with distorted (including hydrogen bonding) and hetero-ligand polyhedra. In particular, analysis of a series of 74 structures with pentacoordinated cations shows that deviations from overall trends are related to structure instability. The possible failure of the method with polyionic structures and `dynamic' structures is discussed.

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INFRARED INTENSITIES AND BOND MOMENTS IN SULPHUR DIOXIDE

Canadian Journal of Physics ◽

10.1139/p57-104 ◽

1957 ◽

Vol 35 (8) ◽

pp. 954-960 ◽

Cited By ~ 12

Author(s):

J. E. Mayhood

Keyword(s):

Dipole Moment ◽

Charge Distribution ◽

Sulphur Dioxide ◽

Normal Coordinate ◽

Molecular Dipole ◽

Molecular Dipole Moment ◽

Equilibrium Charge ◽

Infrared Intensities ◽

Normal Coordinate Calculation

New values have been obtained for the intensities of the three fundamentals of sulphur dioxide. They are A1 = 317 ± 8, A2 = 376±20, A3 = 2560 ± 70, in units of 1010 sec.−1 cm.−1 at S.T.P. The normal coordinate calculation gives values for the bond moment derivatives and for the molecular dipole moment which demonstrate that the amount of charge moving in all three vibrations is greater than that inferred from the equilibrium charge distribution. The involvement of unshared electrons is suggested.

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Derivation of charge distribution from infrared intensities: The case of polyacetylene

Spectrochimica Acta Part A Molecular Spectroscopy ◽

10.1016/0584-8539(85)80118-5 ◽

1985 ◽

Vol 41 (1-2) ◽

pp. 371-380 ◽

Cited By ~ 35

Author(s):

M. Gussoni ◽

C. Castiglioni ◽

M. Miragoli ◽

G. Lugli ◽

G. Zerbi

Keyword(s):

Charge Distribution ◽

Infrared Intensities

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The charge distribution on metal-bonded cyclopentadienyl rings from infrared intensities

Journal of Organometallic Chemistry ◽

10.1016/s0022-328x(99)00326-5 ◽

2000 ◽

Vol 593-594 ◽

pp. 36-43 ◽

Cited By ~ 11

Author(s):

Pier Luigi Stanghellini ◽

Eliano Diana ◽

Enrico Boccaleri ◽

Rosanna Rossetti

Keyword(s):

Charge Distribution ◽

Infrared Intensities

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Simple amidinium carboxylates - An MO treatment of molecular geometry and electronic structure

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890673 ◽

1989 ◽

Vol 54 (3) ◽

pp. 673-683 ◽

Cited By ~ 11

Author(s):

Jiří Krechl ◽

Stanislav Böhm ◽

Svatava Smrčková ◽

Josef Kuthan

Keyword(s):

Electronic Structure ◽

Hydrogen Bonds ◽

Charge Distribution ◽

Chemical Treatment ◽

Quantum Chemical ◽

Geometry Optimization ◽

Molecular Geometry ◽

Chemical Data ◽

Molecular Geometry Optimization ◽

Physico Chemical

Carboxylates of amidines (I, II), substituted guanidine (III) and iso(thio)ureas (IV, V) were prepared. Nonempirical quantum chemical treatment of the electronic structure of simple compounds I-V, based on total molecular geometry optimization, their preparation and physico-chemical data are reported. Interaction between the two amidinium nitrogens and carboxylate oxygens is mediated by hydrogen bonds and alternation of charge distribution.

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