Reaction of dimesityliron(II) (Fe2(mes)4) with the N-heterocyclic carbenes 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) and 1,3-bis(2,6-dimethylphenyl)hexahydropyrimidin-2-ylidene (6-Xyl) afforded the novel trigonal planar complexes [Fe(IPr)(mes)2] (1) and [Fe(6-Xyl)(mes)2] (2), respectively. Both species were structurally characterized by single crystal X-ray diffraction and display structures and magnetic responses consistent with a quintet ground state (S = 2). Reaction of 1 with KC8 in THF afforded K+ salts of the anionic complex [:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]− (3) and the homoleptic organometallic anion [Fe(mes)3]− (4). By contrast, reduction of 2 resulted in extensive decomposition and intractable product mixtures. Complex 3 is coordinated by two ditopic carbanionic carbenes via the C4/C5 position while the C2 position retains unquenched carbenic character and remains vacant for further coordination. This was corroborated by reacting solutions of 3 with one and two equivalents of triethylaluminium (AlEt3) which resulted in the formation of [Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}:C[N(2,6-iPr2C6H3)]2(CH)C}Fe(mes)]− (5) and [Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]− (6), respectively. Both of these species were structurally characterized as [K(2,2,2-crypt)]+ salts.
二
肟基
铁(II)(Fe2(mes)4)与 N-杂环碳烯 1,3-双(2,6-二异丙基苯基)
咪唑-2-亚基(IPr)和 1,3-双(2、(6-Xyl)分别得到了新型三叉平面配合物[Fe(IPr)(mes)2](1)和[Fe(6-Xyl)(mes)2](2)。这两种复合物都通过单晶 X 射线衍射进行了结构表征,并显示出与五元基态(S = 2)一致的结构和磁响应。将 1 与 KC8 在 THF 中反应,可得到阴离子复合物 [:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]- (3) 的 K+ 盐和同性有机
金属阴离子 [Fe(mes)3]- (4)。相比之下,还原 2 会导致大量分解和难以处理的产物混合物。络合物 3 通过 C4/C5 位置配位了两个二价碳阴离子,而 C2 位置则保留了未淬灭的碳化特性,并保持空位以便进一步配位。将 3 的溶液与一当量和二当量的
三乙基铝(AlEt3)反应,形成 [Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}:C[N(2,6-iPr2C6H3)]2(CH)C}Fe(mes)]- (5) 和 [Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]- (6)。这两种物质在结构上都被表征为[K(2,2,2-crypt)]+ 盐。