Synthetic, structural, spectroscopic and calculational studies of a lithium β-diketinimate complex

F. S. Mair; D. Scully; A. J. Edwards; P. R. Raithby; R. Snaith

doi:10.1016/0277-5387(95)00073-2

Synthetic, structural, spectroscopic and calculational studies of a lithium β-diketinimate complex

F. S. Mair, D. Scully, A. J. Edwards, P. R. Raithby, R. Snaith

Research output: Contribution to journal › Article › peer-review

Abstract

Reaction of malonaldehyde bis(phenylimine) monohydrochloride with two equivalents of n-BuLi in the presence of hexamethylphosphoric triamide (HMPA) yielded crystals of [PhN(CH)₃NPhLi·HMPA]₂. The two LiN₂C₃ metallacycles of the dimeric molecule are linked by two bridging oxygens from HMPA. No spectroscopic evidence for dissociative or other equilibria was obtained. The lithium projects above the mean plane of the metallacycles. MNDO calculations on model compounds reproduced bond lengths and angles well, except that all minima were planar, ascribing the envelope conformation to a packing effect. The molecule could best be described as a 1,5-diphenyl-1,5-diazapentadienyl lithium complex, the anion having contributions from diketinimato and two equivalent keteneimine-ene-amido resonance forms. In contrast, the protonated ligand exists in a localized keteneimine-ene-amine form only.

Original language	English
Pages (from-to)	2397-2401
Number of pages	5
Journal	Polyhedron
Volume	14
Issue number	17-18
DOIs	https://doi.org/10.1016/0277-5387(95)00073-2
Publication status	Published - Aug 1995

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

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title = "Synthetic, structural, spectroscopic and calculational studies of a lithium β-diketinimate complex",

abstract = "Reaction of malonaldehyde bis(phenylimine) monohydrochloride with two equivalents of n-BuLi in the presence of hexamethylphosphoric triamide (HMPA) yielded crystals of [PhN(CH)3NPhLi·HMPA]2. The two LiN2C3 metallacycles of the dimeric molecule are linked by two bridging oxygens from HMPA. No spectroscopic evidence for dissociative or other equilibria was obtained. The lithium projects above the mean plane of the metallacycles. MNDO calculations on model compounds reproduced bond lengths and angles well, except that all minima were planar, ascribing the envelope conformation to a packing effect. The molecule could best be described as a 1,5-diphenyl-1,5-diazapentadienyl lithium complex, the anion having contributions from diketinimato and two equivalent keteneimine-ene-amido resonance forms. In contrast, the protonated ligand exists in a localized keteneimine-ene-amine form only.",

author = "Mair, {F. S.} and D. Scully and Edwards, {A. J.} and Raithby, {P. R.} and R. Snaith",

year = "1995",

month = aug,

doi = "10.1016/0277-5387(95)00073-2",

language = "English",

volume = "14",

pages = "2397--2401",

journal = "Polyhedron",

issn = "0277-5387",

publisher = "Elsevier",

number = "17-18",

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TY - JOUR

T1 - Synthetic, structural, spectroscopic and calculational studies of a lithium β-diketinimate complex

AU - Mair, F. S.

AU - Scully, D.

AU - Edwards, A. J.

AU - Raithby, P. R.

AU - Snaith, R.

PY - 1995/8

Y1 - 1995/8

N2 - Reaction of malonaldehyde bis(phenylimine) monohydrochloride with two equivalents of n-BuLi in the presence of hexamethylphosphoric triamide (HMPA) yielded crystals of [PhN(CH)3NPhLi·HMPA]2. The two LiN2C3 metallacycles of the dimeric molecule are linked by two bridging oxygens from HMPA. No spectroscopic evidence for dissociative or other equilibria was obtained. The lithium projects above the mean plane of the metallacycles. MNDO calculations on model compounds reproduced bond lengths and angles well, except that all minima were planar, ascribing the envelope conformation to a packing effect. The molecule could best be described as a 1,5-diphenyl-1,5-diazapentadienyl lithium complex, the anion having contributions from diketinimato and two equivalent keteneimine-ene-amido resonance forms. In contrast, the protonated ligand exists in a localized keteneimine-ene-amine form only.

AB - Reaction of malonaldehyde bis(phenylimine) monohydrochloride with two equivalents of n-BuLi in the presence of hexamethylphosphoric triamide (HMPA) yielded crystals of [PhN(CH)3NPhLi·HMPA]2. The two LiN2C3 metallacycles of the dimeric molecule are linked by two bridging oxygens from HMPA. No spectroscopic evidence for dissociative or other equilibria was obtained. The lithium projects above the mean plane of the metallacycles. MNDO calculations on model compounds reproduced bond lengths and angles well, except that all minima were planar, ascribing the envelope conformation to a packing effect. The molecule could best be described as a 1,5-diphenyl-1,5-diazapentadienyl lithium complex, the anion having contributions from diketinimato and two equivalent keteneimine-ene-amido resonance forms. In contrast, the protonated ligand exists in a localized keteneimine-ene-amine form only.

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U2 - 10.1016/0277-5387(95)00073-2

DO - 10.1016/0277-5387(95)00073-2

M3 - Article

AN - SCOPUS:0000766404

SN - 0277-5387

VL - 14

SP - 2397

EP - 2401

JO - Polyhedron

JF - Polyhedron

IS - 17-18

ER -

Synthetic, structural, spectroscopic and calculational studies of a lithium β-diketinimate complex

Abstract

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