Phillips, Paul Richard (1996) A study of the organometallic chemistry of aluminium, gallium and idium. PhD thesis, University of Warwick.

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Abstract

This thesis describes a study of several aspects of the organometallic chemistry of
aluminium, gallium and indium.
A study has been carried out on the products obtained from the reactions of
trimethyl- and triethyl-metal derivatives of aluminium, gallium and indium with amidines.
The compounds [~M(L)] [L = amidinato (R'NCR''NR'); R' = aryl; R" = H, Me, Ph],
[RM(PhNCR"NPh)2]' and [M(PhNCR"NPh)3](M = Al, R = Me; M = Ga, In; R = Me, Et;
R" = Me, Ph) have been isolated from the reactions of the appropriate trialkyl-metal
derivative with 1, 2 and 3 moles of amidine [R'N(H)CR''NR'] respectively. The compounds
have been fully characterised, and mass spectroscopic data indicate that the compounds
exist as monomers in the gas phase. An X-ray crystallographic study was carried out on
[Me2In(PhNCPhNPh)]. It was found to be monomeric and the ligand is attached in a
bidentate chelating manner. X-ray crystallographic studies on [RM(PhNCPhNPh)2] (M =
Al, Ga, R = Me; M = In, R = Et) and [EtGa(PhNCMeNPh)2] reveal monomeric structures
and the presence of chelating amidinato ligands with highly distorted trigonal bipyramidal
co-ordination at the metal centre. Cleavage of the metal-alkyl bond in some of these
dialkyl- and monoalkyl-metal derivatives on photolysis in the presence of a spin trapping
agent was demonstrated using E.S.R. spectroscopy. An X-ray crystallographic study on
[In(PhNCPhNPh)3] shows a monomeric structure in which the metal centre is six coordinate
and the amidinato ligands are bound in a bidentate chelating manner. Some data
have been obtained on the thermal decomposition products of the metal-amidinato
complexes in view of their potential use as "III-V" semiconductor precursors.
The reactions of the simple N,N'-unsubstituted amidine ligands, butyramidine and
trifluoroacetamidine with Me3Ga have been investigated. The former amidine,
[NH2CButNH], gave the dimethylgallium-butyramidinato compound and mass
spectroscopic data indicate that this compound is oligomeric and exists as both a dimer and
monomer in the gas phase. The latter amidine, [NH2CCF3NH], underwent a condensation
reaction in the presence of M~Ga to form the complex [Me2Ga{HNC(CF3)NC(CF3)NH}].
The molecular structure of this complex was determined by X-ray crystallography. It was
found to consist of a planar six-membered metallocycle containing the N,N'-chelating
trifluoroimidoyltrifluoracetamidinato ligand and a distorted tetrahedral co-ordination
environment around the metal.
Several new indium(III) tetraaza-macrocycle complexes have been prepared using
the unsaturated ligand 5,7,12, 14-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine
["H2tmtaa"].The molecule structures of the compounds [XIn(tmtaa)] (X = Et, Cp, Cl) have
been determined by X-ray crystallography. In each case, the structure consists of an InX
fragment bonded to the four nitrogen atoms of the macrocyclic ligand. These structures
provide unusual examples of indium in a five co-ordinate square based pyramidal coordination
geometry in which the indium is centrally bound above the N4 plane of the
macrocycle. The effects of change of both metal size and axial ligand on the molecular
geometry of these types of complex have been discussed in detail.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Organometallic chemistry , Aluminum , Gallium
Official Date:	January 1996
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Wallbridge, M. G. H.
Sponsors:	Engineering and Physical Sciences Research Council ; Associated Octel Company
Extent:	xix, 296 leaves
Language:	eng

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