三芽氮異環碳烯與其金屬化合物之合成與鑑定

Abstract

近年來橋接式的多芽氮異環碳烯受到許多的注目，因為他們具有極大的潛力建構有機金屬聚合物亦或是同元聚合物。致力於拓展這個領域，我們以具有高度對稱性和特定角度的分子三亞苯為基本骨架，設計並合成一系列具有不同氮取代基的平面三牙咪唑鹽 (4a-c and 5d-e)。當取代基為1,1-二甲基乙基和1,3,5-三甲苯時，藉由簡單的脫氫反應可得到穩定的氮異環碳烯，進而可與金屬前驅物反應生成相對應的三核金的金屬錯合物 (6a-(AuCl)3, 7a-(Au(DMAP)3(PF6)3 and 7b-(AuCl)3)。此外，4b 直接與乙酸銀進行金屬化反應也可以得到三核銀的金屬錯合物 (7b-(AgOAc)3)。若是取代基為二苯甲烷和正丁基時，一系列的三核金屬錯合物包括(5c-(Rh(COD)Cl)3, 6e-(AgOAc)3, 7e-(Hg(OAc)2)3, 8e-(Ni(Cp)I)3和 9e-(Rh(COD)Cl)3)皆可直接藉由三芽咪唑鹽與相對應的金屬前驅物反應得到。此外，我們也合成出帶有銀金屬(8a: R = tert-butyl; 6c: R = diphenylmethyl)，鈀金屬(9a: R = tert-butyl)和金金屬(10a: R = tert-butyl)的有機金屬聚合物，以期橋接式的多芽氮異環碳烯能在以有機金屬為主體之延伸性材料的建構及異相催化上能有更進一步的發展。

Bridging type poly-N-heterocyclic carbenes have attracted much attention recently because of their potential applications in constructing organometallic polymers or homopolymers. In order to contribute to this field, we designed and synthesized a series of planar tris-imidazolium salts with various N-substituents, based on the highly symmetric and angular triphenylene backbone (4a-c and 5d-e). With t-butyl and mesityl substituents, free tris-NHCs could be generated and isolated via deprotonation, and further reacted with metal precursors to afford the corresponding tri-nuclear gold complexes (6a-(AuCl)3, 7a-(Au(DMAP)3(PF6)3 and 7b-(AuCl)3). Direct metalation of 4b with AgOAc gave the tri-Ag complex (7b-(AgOAc)3). For the diphenylmethyl (4c) and n-butyl (5e) substituted ones, tri-nuclear metal complexes (5c-(Rh(COD)Cl)3, 6e-(AgOAc)3, 7e-(Hg(OAc)2)3, 8e-(Ni(Cp)I)3, and 9e-(Rh(COD)Cl)3) could also be isolated by direct metalation when treated with appropriate metal precursors. In addition, the Ag-NHC (8a: R = tert-butyl; 6c: R = diphenylmethyl) and Au-NHC (9a: R = tert-butyl) organometallic polymers have been synthesized and investigated as well.