The lithium bond reexamined

Sannigrahi, A. B.; Kar, Tapas; Niyogi, B. Guha; Hobza, Pavel; Schleyer, Paul v. R.

doi:10.1021/cr00104a007

Cited by 149 publications

(101 citation statements)

References 29 publications

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“…Accordingly, the three-electron, cubic valence indices (CVI), measuring contributions to the corresponding third-order change in the diagonal part of the three-electron density matrix, are similarly represented by the corresponding cubic forms of the molecular CBO displacements relative to the SAL. It has been demonstrated (1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14] that these two-electron valence numbers reproduce intuitive chemical expectations quite adequately for typical molecules and model transition states of simple chemical reactions. The corresponding UHF three-electron corrections have been shown to be small (13).…”

Section: Introductionmentioning

confidence: 85%

Quantum chemical valence indices from the one-determinantal difference approach

Nalewajski¹,

Mrozek²,

Mazur³

1996

Can. J. Chem.

132

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The recently introduced quadratic (two-electron) valence indices, ionic and covalent, derived from the HartreeFock finite-difference approach, are applied to selected organic and inorganic molecules to demonstrate their utility in monitoring chemical bonding patterns in molecular systems. The indices are defined in terms of differerences between simultaneous probabilities of finding two electrons on specified atoms, calculated from the molecular and separated-atomlimit (SAL) wave functions, respectively, in the UHF approximation. The total quadratic valence number represents the overall number of chemical bonds in the system under consideration; it is interpreted as the molecular expectation value of the difference operator of the molecular and SAL density operators. This interpretation leads to a new set of ionic atomic and diatomic valence components; these modified valence numbers are discussed using the two-orbital model in the UHF scheme. A new procedure is proposed for dividing the one-center contributions to the bond valences; it generates effective bond orders in qood agreement with chemical expectations. The new valence quantities are tested on selected typical molecules and prototype hydrogen-bonded dimers. A more extensive study has been canied out on small-ring propellanes, to examine changes in bond valences between bridgehead atoms in selected systems.

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Section: Introductionmentioning

confidence: 85%

Quantum chemical valence indices from the one-determinantal difference approach

Nalewajski¹,

Mrozek²,

Mazur³

1996

Can. J. Chem.

132

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“…[14][15][16][17] Lithium, as a congener of hydrogen, undergoes similar interactions to form the lithium bond. [18] Lithium bonds are much less investigated than hydrogen bonds. Like the hydrogen bonds, lithium bonds are also classified as conventional and unconventional.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Interplay between Lithium Bond and Hydrogen Bond in Complexes Involved with HLi and HCN

et al. 2009

ChemPhysChem

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The lithium- and hydrogen-bonded complex of HLi-NCH-NCH is studied with ab initio calculations. The optimized structure, vibrational frequencies, and binding energy are calculated at the MP2 level with 6-311++G(2d,2p) basis set. The interplay between lithium bonding and hydrogen bonding in the complex is investigated with these properties. The effect of lithium bonding on the properties of hydrogen bonding is larger than that of hydrogen bonding on the properties of lithium bonding. In the trimer, the binding energies are increased by about 19% and 61% for the lithium and hydrogen bonds, respectively. A big cooperative energy (-5.50 kcal mol(-1)) is observed in the complex. Both the charge transfer and induction effect due to the electrostatic interaction are responsible for the cooperativity in the trimer. The effect of HCN chain length on the lithium bonding has been considered. The natural bond orbital and atoms in molecules analyses indicate that the electrostatic force plays a main role in the lithium bonding. A many-body interaction analysis has also been performed for HLi-(NCH)(N) (N=2-5) systems.

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“…Though the lithium bond resembles the hydrogen bond in many respects a number of dissimilarities between the two have been noted.14, 15 We have investigated16 a series of lithium as well as hydrogen bonded complexes of various bases using donorÈacceptor models based on NBO analysis ¤ Present address : Department of Materials Chemistry, Graduate School of Engineering, Tohoku University, Aoba -Yama 07, Sendai 980-8579, Japan and discussed the participation of various orbitals in these bonding interactions. In this paper we have chosen a set of three n-donors namely trimethylamine, dimethyl ether and dimethyl sulÐde and investigated their interaction with HF and LiF using higher level ab initio and DFT methods.…”

Section: Introductionmentioning

confidence: 99%

Ab initio and DFT investigations of lithium/hydrogen bonded complexes of trimethylamine, dimethyl ether and dimethyl sulfide

Ammal¹,

Venuvanalingam²

1998

Faraday Trans.

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Ab initio and DFT investigations of lithium/hydrogen bonded complexes of trimethylamine, dimethyl ether and dimethyl sulÐde S. Salai Cheettu Ammal¤ and P. Venuvanalingam* Department of Chemistry, Bharathidasan University, T iruchirappalli -620 024, India 17th June 1998, Accepted 24th June 1998 Recei¿ed Ab initio and DFT computations have been carried out on LiF and HF complexes of a set of n-donors viz. trimethylamine, dimethyl ether and dimethyl sulÐde with a 6-31]]G(d,p) basis set. The e †ect of correlation has been included with MP2, MP4 and DFT calculations. NBO analyses of the wavefunctions have been performed to examine the intermolecular interaction at the orbital level. Calculations reveal that these donors form strong n ] r* complexes and computed binding energies of the complex agree very well (CH 3 ) 2 OÉ É ÉHF with the experimental binding energies from IR spectroscopy. LiF forms stronger complexes than HF, and the e †ect of correlation on the hydrogen bond energy is considerable compared to the lithium bond energy. Though charge transfer interaction contributes to the stability of both LiF and HF complexes, it plays a less dominant role in lithium bonded complexes. While amine and ether donate their lone pair, sulÐde donates n s an lone pair and this results in perpendicular intermolecular bonds in sulÐde complexes.n p

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The lithium bond reexamined

Cited by 149 publications

References 29 publications

Quantum chemical valence indices from the one-determinantal difference approach

Quantum chemical valence indices from the one-determinantal difference approach

Theoretical Study of the Interplay between Lithium Bond and Hydrogen Bond in Complexes Involved with HLi and HCN

Ab initio and DFT investigations of lithium/hydrogen bonded complexes of trimethylamine, dimethyl ether and dimethyl sulfide

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