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Synthesis, structural characterization and reactivity study of novel twelve-, thirteen-, and fourteen-vertex carboranes and their derivatives. / CUHK electronic theses & dissertations collection

By introducing a linkage between two cage carbon atoms, C,C'-linked nido-carborane salts Na2[(CH2)nC 2B10H10] (n = 5, 6) and arachno-carborane salts Li4[(CH2)nC2B10H 10] (n = 3, 4) were synthesized. The trimethylene linked carborane 1,2-(CH 2)3-1,2-C2B10H10 is a good starting material for polyhedral expansion reactions. The sequential sodium reduction followed by capitation reaction with RBX2 gave 13-vertex carboranes 3-R-1,2-(CH2)3-1,2-C2B11 H10 in moderate yields. Electrophilic substitution reactions of 1,2-(CH2)3-1,2-C2B11H 11 with suitable electrophiles gave partially substituted products 8,9,10,11,12,13-X 6-1,2-(CH2)3-1,2-C2B11H 5 (X = Me, Br, I). 13-Vertex closo-carboranes can be reduced to form 13-vertex nido-species [(CH2) 3C2B11H10R]2- by groups 1 and 2 metals. Capitation reactions of Na2[(CH2) 3C2B11H11] with dibromoborane or suitable metal halides afforded 14-vertex carborane 2,3-(CH2)3-2,3-C 2B12H12 or metallacarboranes 2,3-(CH2) 3-8-L-8,2,3-NiC2B11H11 (L = dppe, dppen) and 2,3-(CH2)3-1-(p-cymene)-1,2,3-RuC 2B11H11. Reduction of 14-vertex closo -carborane yielded 14-vertex nido-species Na 2[(CH2)3C2B12H12]. It reacted with dibromoborane to afford a new 14-vertex carborane 2,13-(CH 2)3-2,13-C2B12H12, rather than a 15-vertex one. However, a 15-vertex ruthenacarborane 1,4-(CH2 )3-7-(p-cymene)-7,1,4-RuC2B 12H12 was obtained by the capitation reaction of Na 2[(CH2)3C2B12H12] with [(p-cymene)RuCl2]2. / The reaction of Cp2ZrCl2 with Li2C 2B10H10 gave Cp2Zr(mu-Cl)(mu-C 2B10H10)Li(OEt2)2. Its reactivity toward unsaturated polar organic substrates CyN=C=NCy, PhN3, tBuNC, and PhCN resembled that of zirconocene-carboryne complex yielding a series of insertion products. The Zr-carboryne complexes (eta 5-C5Me5)(eta3-C2B 10H10)Zr(mu-Cl)2Li(THF)2, (eta 5-C5Me5)(eta3-C2B 10Me8H2)Zr(mu-Cl)2Li(OEt2) 2, and (eta5-C5Me5)Zr[eta 3-CyNC(Me)NCy](eta3-C2B10H 10) were synthesized by salt metathesis method. Among them, (eta 5-C5Me5)Zr[eta3-CyNC(Me)NCy](eta 3-C2B10H10) was active toward unsaturated polar organic substrates. Some late transition metal-carboryne complexes (PPh 3)2M(eta2-C2B10H 10) (M = Ni, Pd, Pt) were obtained from the reactions of Li2C 2B10H10 with (PPh3)2MCl 2. The ligand substitution reactions of (PPh3)2Ni(eta 2-C2B10H10) with different phosphines were studied, which revealed the labile property of the coordinated PPh 3. Different from the Zr-carboryne complexes, (PPh3) 2Ni(eta2-C2B10H10) showed regioselective [2+2+2] cycloaddition toward less bulky internal alkynes affording highly substituted benzocarboranes. / Deng Liang. / "July 2006." / Adviser: Zuowei Xie. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6393. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 152-168). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in english and Chinese. / School code: 1307.

Identiferoai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_343793
Date January 2006
ContributorsDeng, Liang., 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 (xvi, 180 p. : 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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