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Title: Complexation of early- and post-transition metal halides with aza-, oxa-, and thiamacrocyclic ligands
Author: Lakin, Miles T.
ISNI:       0000 0001 3604 0299
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1993
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Reaction of MCI, (M » As, Sb, Bi) with the homoleptic polythiamacrocycles 9S3, 12S4, 15S5, and 18S6 has lead to the isolation o f the molecular adducts SbCI,-9S3 (1), SbCl,- 15S5 (2), (SbCl,)2 18S6 (3), BiCI,-9S3-'AMeCN (4), BiCl,12S4 (5), BiCI,-15S5'AM eCN (6), BiCl, 18S6 (7). The solid state structures o f (1), (3), (5), (6), and (7) have been determined by single crystal X-ray diffraction methods; weak metal-sulfur bonding being confirmed. Trends in complex stability have been appraised in terms of bound-ligand strain energy using Molecular Mechanics calculations. Investigations into the coordination chemistry of MCI, (M - Sc, Ti, V) and TiC^ with 9S3 have lead to the formation of TiCl4-9S3 (8), TiCl,-9S3 (9), and [VOCl2(9S3)J (10). The latter, an unexpected oxidation product, has been structurally characterised using single crystal X-ray diffraction; facial binding by the 9S3 yields a distorted octahedral vanadium coordination geometry. Reaction of MCI, (M « As, Sb, Bi) with TMC has lead to hydrolysis o f the metal halide. Mediation o f the hydrolysis reaction has permitted the compounds (H2(TMC)][Sb2OCl6J (11), and [H2(TMC)KAv O |C1m] (12) to be deposited in a crystalline form. The nature o f (11) and (12) has been established using single crystal X-ray diffraction techniques. The anions have been compared with other, closely related, species. The diprotonated cations of TMC exhibit the sequential stereochemistry RRSS (11) and RSRS (12). The single crystal X-ray structure of the parent macrocycle, TMC, has been determined and found to comprise of independent molecules with sequential stereochemistry RSSR and RRSS. Geometric and strain energy trends have been considered for the neutral and protonated forms o f TM C and cyclam. The use o f antimony pentachloride as a halide abstraction agent from M CI, (M * Sc, Y, La) has facilitated the generation o f a variety of cationic species, depending upon the reaction stoichiometry used. These cations have been stabilised using the macrocycles 1204, ISOS, BzlSOS and 1806 to allow isolation of the compounds [ScCl2(M eC N)(1204)][SbClJ (13), [ScCl2( 1505)J[SbCI*J (14), [ScCI2(Bzl505)][SbCl.J (15), [ScClj( 1806)](SbClJ (16), (Y(MeCN),(1204)][SbCy,(17), [Y(MeCN),(1806)][SbCU, (18), [La(MeCN),(1204)](SbCUj (19), and [La(M eCN),(1806)][SbClJ, (20). The single crystal X-ray structures of (15) and (16) both show a pentagonal bipyramidal geometry around scandium with the crown ether providing an equatorial girdle and the two chlorine atoms assuming the axial positions.
Supervisor: Not available Sponsor: Science and Engineering Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry