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Part I. Organic stereochemistry at a pseudo-octahedral center. Part II. Molecular surgery of fullerene carbon(60)

Posted on:2001-12-11Degree:Ph.DType:Dissertation
University:University of California, Los AngelesCandidate:Qian, WenyuanFull Text:PDF
GTID:1461390014452525Subject:Chemistry
Abstract/Summary:
Chapter I gives a general review on the regiochemistry of multiple addition; to fullerene C60. A complete control over the addend permutation at pseudo-octahedral locations on C60 is introduced as the primary target of this work. In addition, a molecular surgery approach toward a non-classical fullerene C2v-C62 is proposed.; Chapter II presents the design and preliminary test of a “mer-3+3” sequential regiocontrol strategy. The preparation of the key precursor, a tethered trans-1 bis-Diels-Alder adduct of C60, and its subsequent highly selective functionalization to the first “mer-A3+B3” hexakisadduct is described.; Chapter III details a comprehensive study of the regioselectivity of every intermediate pseudo-octahedral addition pattern of C60. By judiciously selecting the addition sequence and the type of addends, a complete series of seven isomeric “A2+B2+C2” hexakisadducts can be synthesized in a facile, parallel manner.; Chapter IV describes the final accomplishment of the complete control over addend permutation at pseudo-octahedral sites of C 60, as demonstrated by the efficient preparation of a pair of fully permutated and fully differentiated edge-to-face isomers. A refined procedure of the initial “mer-3+3” regiocontrol strategy, which makes exquisite utility of both steric and electronic effects, is essential to overcome a significant regioselection obstacle at the late stage of multifunctionalization.; Chapter V reports the formation of C62 in gas phase from its synthetic precursor. Stable C62 derivatives are obtained in a designed cascade reaction between C60 and tetrazines. The expected 4-membered ring within the fullerene framework is confirmed in the preliminary X-ray structure of such compounds.; Chapter VI describes a systematic investigation of a photochemically promoted tandem [4+4]/retro[2+2+2] rearrangement reaction. A novel strategy for the regioselective multiple application of this reaction is also described.
Keywords/Search Tags:Fullerene, Chapter, Pseudo, -octahedral, Addition
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