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Synthesis, structure and reactivity of group 4 metal complexes bearing cyclopentadienyl-carboranyl ligands. / CUHK electronic theses & dissertations collection

[eta5:sigma-Me2C(C5H4 )(C2B10H10]Zr[eta2-S 2C2B10H10](NHMe2)2 was prepared by amine elimination reaction between [eta5:sigma-Me 2C(C5H4)(C2B10H10)]Zr[NMe 2)2 and 1,2-(HS)2-1,2-C2B10 H10. It underwent ligand substitution reaction with XylNC to generate [eta5:sigma-Me2C(C5H 4)(C2B10H10]Zr[eta2-S 2C2B10H10][2,6-(CH3) 2C6H3N=C]2 and reacted with THE to give ring opening product [eta5:sigma-Me2C(C 5H4)(C2B10H10]ZR-[eta 2-S2C2B10H10][sigma-O(CH 2)4NHMe2)]. Zirconium-promoted nucleophilic reaction of dimethylamine with various kinds of unsaturated polar organic substrates, such as PhCN, PhNCO, nBuNCS and MA were studied. / Direct deboration of group 4 metal carboranyl complexes was achieved by reactions of [eta5:sigma-Me2C(C5H 4)(C2B10H10]M[NMe2) 2 (M = Zr, Hf), [eta5:sigma-Me2C(C 9H6)(C2B10H10]Zr[NMe 2)2 or [eta5:sigma-H2C(C 13H8)(C2B10H10]Zr[NMe 2)2 with excess diamines. The resultant metal dicarbollide complexes [eta5:eta6-Me2C(C 5H4)(C2B9H10)]Zr[eta 2-N(Me)(Ch2)2NH(Me)] and [eta5:eta 6-Me2C(C5H4)(C2B 9H10]Zr[eta2-[NMe)(CH2) 3NH(Me)] were active toward unsaturated molecules, like nBuNCS, iPr-N=C=N- iPr and nBuNC, to give mono-insertion products. [eta5:eta6-Me2C(C 5H4)(C2B9H10)]Zr[eta 2-N(Me)(CH2)3NH(Me)] was able to be deprotonated by nBuLi to give a lithium salt {[eta 5:eta-6-Me2C(C5H4)(C 2B9H10)]Zr[eta2-N(Me)(CH 2)3N(Me)Li]}2. It reacted with [HNEt3][BPh 4] to afford cationic zirconium species [eta5:eta 6-Me2C(C5H4)(C2B 9H10]Zr{eta2-NH(Me)(CH2) 3NH(ME)}][BPh4]. The dichloro species [eta5:eta 6-Me2C(C5H4)(C2B 9H10}MCl2][Li(DME)3)] (M = Zr, Hf) were reduced by sodium metal to produce a new class of metallacarbornes bearing arachno-eta6-C2B9 tetraanion. / The amine exchange reaction between [eta5:sigma-Me 2C(C5H4)(C2B10H10]M[NMe 2)2 (M = Zr, Hf, Ti) and N, N'-dimethylethylenediamine or N, N'-dimethylpropane-1,3-diamine gave [eta5:sigma-Me 2C(C5H4)(C2B10H10]M-[eta 2N(Me)(CH2)2N(Me)] (M = Zr, Ti) or [eta 5:sigma-Me2C(C5H4)(C2B 10H10]M-[eta2N(Me)(CH2) 3N(Me)] (M= Zr, Hf, Ti) in good yields. The metal-nitrogen bonds in these group 4 metal diamide complexes were very reactive toward unsaturated polar organic substrates, such as RNC, RNCS, RNCO, R-N=C=N-R and RCN to give multiple insertion products. The carbodiimide and XylNC (Xyl = 2,6-Me 2C6H3) insertion products [eta5:sigma-Me 2C(C5H4)(C2B10H10]M-[eta 3N(Me)(CH2)3N(Me)C(=NR)NR] (M = Zr, R = iPr, Cy; M = Hf, R = Cy) and [eta5:sigma-Me 2C(C5H4)(C2B10H10]M-[eta 2:eta2-N(Xyl)=CN(Me)(CH2)3N(Me)C=N(Xyl)] (M = Zr, Hf) also showed reactivities toward unsaturated molecules, resulting in the de-insertion of carbodiimide and XylNC. Different reactivity patterns were observed, depending on the nature of metal atoms and substrates. / Sit, Mei Mei. / Adviser: Zuowei Xia. / Includes supplementary digital materials. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 247-267). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Identiferoai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344724
Date January 2010
ContributorsSit, Mei Mei., Chinese University of Hong Kong Graduate School. Division of Chemistry.
Source SetsThe Chinese University of Hong Kong
LanguageEnglish, Chinese
Detected LanguageEnglish
TypeText, theses
Formatelectronic resource, microform, microfiche, 1 online resource (xxiii, 285 leaves : ill.)
RightsUse of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

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