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Title: Synthesis, structure and chemical studies of cationic M(IV) species where M = Ti, Zr, Hf and Sn
Author: Palin, Janet
ISNI:       0000 0001 3464 7847
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1994
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The reactions of the Lewis acid SbCl, with MC14 (M=Ti, Zr, Hf and Sn) have allowed the isolation of the hexachloroantimonate(V) salts [MCl3LJ[SbCl6], where M=Ti, Sn, n=3, L = MeCN and M =Zr, Hf, n=4, L=l,4-dioxane and [TiClL7][SbCl6]3, L = MeCN with full spectroscopic characterisation. Other routes to the formation of the cationic species [TiCl^]4 have been investigated, including halide abstraction using the reagents AgBPh4, NaBPh4 and AgBF4. Reactions of [TiCl3(MeCN)3][SbCl6] with the crown ether ligands, 1,4,7,10-tetraoxocyclododecane(12-C-4), 1,4,7,10,13-pentaoxocyclopentadecane (15-C-5) and 1,4,7,10,13,16-hexaoxocyclooctadecane (18-C-6) have been studied. The products obtained are not the expected direct adducts ie. ligand exchange following replacement of MeCN by crown ether but rather the //-oxo-bridged [{TiC10i-O)(12-C-4)}2][SbCl6]2-2CH2Cl3 and [{TiCl(/x-0)(15-C-5)}2][SbCl6]2. The 12-crown-4 species was studied by X-ray diffraction methods. Plausible routes to their formation are forwarded. In the case of 18-C-6, the hydrolysis product, [H30(18-C-6)][SbCl6] was isolated. Reactions of the neutral MC14 (M= Ti, Zr, Hf and Sn) with crown th ioethers, 1,4,7-trith iacyclononane (9-S-3), 1,4,7,10-tetrath iacyclododecane ,(12- S-4), 1,4,7,10,13-pentathiacyclopentadecane, (15-S-5) and 1,4,7,10,13,16- hexathiacyclohexadecane, (18-S-6) have been studied. The reactions led to the isolation of [TiCl4(9-S-3)], [SnCl3(9-S-3)]2[SnCl6] and 2SnCI418-S-6. The latter two compounds were characterised by X-ray diffraction methods. Reaction of the compound [TiCI3(MeCN)3][SbCl6] with the crown thioether 9-S-3 was unsuccesful. Extending the choice of ligands to include macrocyclic azaoxacrown ethers 1, 4, 7-trioxa-10-azacyclododecane (l-aza-12-crown-4), 1, 4, 7, 10-tetraoxa-13- azacyclopentadecane (l-aza-15-crown-5) and 1, 4, 7, 10, 13-pentaoxa-16- azacyclooctadecane (l-aza-18-crown-6), led to the isolation of complexes of the type [H2L]2[TiCl5(H20)]2,H20MeCN where L=appropriate azaoxacrown. Controlled hydrolysis reactions of solvated [TiClJ(4n)+ species have been studied as a route to titanoxanes. The ¿»«-adduct TiCl4(MeCN)2 provides the neutral tetranuclear /z-oxo compound [TiCI2(MeCN)2(/*-0)]4 whilst the pentachloroanion in the form of |Mg(MeCN)6][TiCl3(MeCN)]2 yields the p-oxo- dititanium anion [{TiCI4(MeCN)}2(p-0)]42\Both products were the subject of X- ray structure examination. During an exchange programme involving the University of Alcalá de Henares, Madrid, the reaction of Cp'TiCl3 (where Cp" = i/’-(l,3-ditert-C4H9)Cp) with the carboxylic acid p-toluic acid was studied. Following in situ formation of Cp‘TiMe3, reaction with 3 equivalents of p-toluic acid afforded crystals of [Cp*Ti(p-0)(C6H4CH3C02)]2. The compound was structurally characterised by X-ray diffraction.
Supervisor: Not available Sponsor: Sussex European Research Centre
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry