Organometallic Complexes as Ligands

Wilson, Victor Alexander (1971) Organometallic Complexes as Ligands. PhD thesis, University of Glasgow.

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Abstract

Complexes which contain two or more transition metals have been prepared and characterised. The preparations have, in the main, been carried out using ligand replacement reactions leading to complexes which contain two transition metals linked together by two bridging ligands. Spectroscopic evidence suggests that some of the complexes contain metal-metal bonds whereas others do not. The metal-metal bond in these complexes is unusual in that it is a dative bond formed by two electrons which formally belong to only one of the metals. The complexes which have been prepared and studied are as follows: bis-pi-cycl opentadienyl titanium di-u-organothio tetracarbonyls of Group VI, Cp2Ti [SR]2M'(CO)4, I, (R=Me,Ph; M'= Cr,Mo,W); chelating diphosphine or diarsine palladium or platinum di-u- organothio tetracarbonyls of Group VI, (L-L )M (L-L=1,2 bis-diphenyl phos phino ethane, O-phenylene bis-diethylarsine; M=Pd,Pt; R = Me , Ph; M' =Cr,Mo,W); bis-pi-cyclopentadienyl titanium di-mu-organo thio cuprous halides, (C p2 Ti [SR]2 CuX)n, IV, (R = Me,Ph; X = Cl,Br); 1,2 bis-diphenylphosphino ethane palladium or platinum di-mu-methylthio palladium dichlorides, Ph2PCH2CH2PPh2M [SMe]2PdCl2, VI, (M = Pd,Pt); and 1,2 bis-diphenyl phosphino ethane palladium II di-mu-chloro palladium dichloride, Ph2PCH2CH2PPh2Pd [Cl]2PdCl2, VII In order to examine the properties of the above complexes, it has been necessary to prepare and study the "parent" complexes RSCH2CH2SRM'(CO)4 , III, (R=Me,Ph; M'=Cr,Mo,W); (RSCH2CH2SRCuX)n, V, (R = Me,Ph; X=Cl,Br); Cp2Ti(SR)2, (R=Me,Ph); and (L-L)M(SR)2, (L-L=1,2 bis-diphenylphosphino ethane, O-phenylene bis-diethyl arsine; M=Pd,Pt; R=Me,Ph). Because of the different physical properties, especially solubility, of the complexes prepared, it has been found necessary to use different techniques to examine their chemical properties. The molecular structure of Cp2Ti[5Me]2Mo(CO)4, together with infra-red, 1Hn. m.r., and electronic data suggest that complexes I contain a metal-metal bond. There is evidence for a metal-metal bond in complexes IV, from their electronic spectra. The infra-red (4,000- 400cm.-1), far infra-red (400-40cm.-1),and electronic spectra of complexes II, VI, and VII show no evidence of a metal-metal bond. Tentative correlations have been made between the metal-bridge stretching frequencies and the strengths of the metal-bridge bonds. The failure to prepare (by nucleophilic displacement or elimination reactions) complexes containing two transition metals bridged by silicon or titanium, and the unusual products obtained from some of the ligand replacement reactions are assigned to lability or overstability of the reaction intermediates or lability of the desired products.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry, Inorganic chemistry
Date of Award: 1971
Depositing User: Enlighten Team
Unique ID: glathesis:1971-78544
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 28 Feb 2020 12:09
Last Modified: 28 Feb 2020 12:09
URI: http://theses.gla.ac.uk/id/eprint/78544

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