MOLECULAR-ORBITAL BOND INDEX (MOBI) CALCULATIONS ON SELECTED ORGANO-LITHIUM AND LITHIUM ATE SPECIES - EVIDENCE FOR LI=H-C 3-CENTER INTERACTIONS

D BARR, R SNAITH, Robert Mulvey, P G PERKINS

Research output: Contribution to journalArticle

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Abstract

Molecular Orbital Bond Index (MOBI) calculations have been carried out on selected organolithium tetramers and hexamers, and on certain lithium 'ates, all of which had previously been shown to exhibit short Li ⋯ HC contacts in their solid-state structures. Species so examined comprised (MeLi)4, (EtLi)4 and their “dimerized” forms (to mimic the further association of these tetramers in the crystal), (Me2CHLi)6 and (H3SiCH2Li)6, [as models for (c-C6H11Li)6 and (Me3SiCH2Li)6, respectively], and (LiAlEt4)n and (LiBMe4)n, with n = 1,2. The calculational results indicate that the short Li ⋯ HC distances observed reflect genuine three-centre interactions between lithium centres and CH bonds: thus, summed Li ⋯ H bond indices (measures of the electron density between the nuclei concerned) contribute significantly (44 → 14%) to the total lithium valency, and concomitant weakening of the indices of involved CH bonds (0.80–0.90; cf. indices of distant CH bonds, ca 0.95) is observed.
LanguageEnglish
Pages2119-2128
Number of pages10
JournalPolyhedron
Volume7
Issue number21
DOIs
Publication statusPublished - 1988

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Molecular orbitals
Lithium
molecular orbitals
lithium
interactions
Carrier concentration
Association reactions
Crystals
solid state
nuclei
crystals

Keywords

  • organolithium
  • lithium'ate species
  • organolithium tetramers
  • tetramers

Cite this

@article{d37378b02ab34230b897aafeaf8a5cae,
title = "MOLECULAR-ORBITAL BOND INDEX (MOBI) CALCULATIONS ON SELECTED ORGANO-LITHIUM AND LITHIUM ATE SPECIES - EVIDENCE FOR LI=H-C 3-CENTER INTERACTIONS",
abstract = "Molecular Orbital Bond Index (MOBI) calculations have been carried out on selected organolithium tetramers and hexamers, and on certain lithium 'ates, all of which had previously been shown to exhibit short Li ⋯ HC contacts in their solid-state structures. Species so examined comprised (MeLi)4, (EtLi)4 and their “dimerized” forms (to mimic the further association of these tetramers in the crystal), (Me2CHLi)6 and (H3SiCH2Li)6, [as models for (c-C6H11Li)6 and (Me3SiCH2Li)6, respectively], and (LiAlEt4)n and (LiBMe4)n, with n = 1,2. The calculational results indicate that the short Li ⋯ HC distances observed reflect genuine three-centre interactions between lithium centres and CH bonds: thus, summed Li ⋯ H bond indices (measures of the electron density between the nuclei concerned) contribute significantly (44 → 14{\%}) to the total lithium valency, and concomitant weakening of the indices of involved CH bonds (0.80–0.90; cf. indices of distant CH bonds, ca 0.95) is observed.",
keywords = "organolithium , lithium'ate species , organolithium tetramers , tetramers",
author = "D BARR and R SNAITH and Robert Mulvey and PERKINS, {P G}",
year = "1988",
doi = "10.1016/S0277-5387(00)81790-8",
language = "English",
volume = "7",
pages = "2119--2128",
journal = "Polyhedron",
issn = "0277-5387",
number = "21",

}

MOLECULAR-ORBITAL BOND INDEX (MOBI) CALCULATIONS ON SELECTED ORGANO-LITHIUM AND LITHIUM ATE SPECIES - EVIDENCE FOR LI=H-C 3-CENTER INTERACTIONS. / BARR, D ; SNAITH, R ; Mulvey, Robert; PERKINS, P G .

In: Polyhedron, Vol. 7, No. 21, 1988, p. 2119-2128.

Research output: Contribution to journalArticle

TY - JOUR

T1 - MOLECULAR-ORBITAL BOND INDEX (MOBI) CALCULATIONS ON SELECTED ORGANO-LITHIUM AND LITHIUM ATE SPECIES - EVIDENCE FOR LI=H-C 3-CENTER INTERACTIONS

AU - BARR, D

AU - SNAITH, R

AU - Mulvey, Robert

AU - PERKINS, P G

PY - 1988

Y1 - 1988

N2 - Molecular Orbital Bond Index (MOBI) calculations have been carried out on selected organolithium tetramers and hexamers, and on certain lithium 'ates, all of which had previously been shown to exhibit short Li ⋯ HC contacts in their solid-state structures. Species so examined comprised (MeLi)4, (EtLi)4 and their “dimerized” forms (to mimic the further association of these tetramers in the crystal), (Me2CHLi)6 and (H3SiCH2Li)6, [as models for (c-C6H11Li)6 and (Me3SiCH2Li)6, respectively], and (LiAlEt4)n and (LiBMe4)n, with n = 1,2. The calculational results indicate that the short Li ⋯ HC distances observed reflect genuine three-centre interactions between lithium centres and CH bonds: thus, summed Li ⋯ H bond indices (measures of the electron density between the nuclei concerned) contribute significantly (44 → 14%) to the total lithium valency, and concomitant weakening of the indices of involved CH bonds (0.80–0.90; cf. indices of distant CH bonds, ca 0.95) is observed.

AB - Molecular Orbital Bond Index (MOBI) calculations have been carried out on selected organolithium tetramers and hexamers, and on certain lithium 'ates, all of which had previously been shown to exhibit short Li ⋯ HC contacts in their solid-state structures. Species so examined comprised (MeLi)4, (EtLi)4 and their “dimerized” forms (to mimic the further association of these tetramers in the crystal), (Me2CHLi)6 and (H3SiCH2Li)6, [as models for (c-C6H11Li)6 and (Me3SiCH2Li)6, respectively], and (LiAlEt4)n and (LiBMe4)n, with n = 1,2. The calculational results indicate that the short Li ⋯ HC distances observed reflect genuine three-centre interactions between lithium centres and CH bonds: thus, summed Li ⋯ H bond indices (measures of the electron density between the nuclei concerned) contribute significantly (44 → 14%) to the total lithium valency, and concomitant weakening of the indices of involved CH bonds (0.80–0.90; cf. indices of distant CH bonds, ca 0.95) is observed.

KW - organolithium

KW - lithium'ate species

KW - organolithium tetramers

KW - tetramers

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