Iron and Cobalt Complexes with Thiacarborane Ligands

Reaction of tBuNC with nido-6-SB9H11 in the presence of Proton Sponge gives the nido-thiacarborane 7-tBuNH2-7,9-CSB9H9 (2) apparently via rearrangement of the initially formed nido-7-tBuNH2-7,8-CSB9H9 (1) isomer. Deprotonation of 2 gives the anion [nido-7-tBuNH-7,9-CSB9H9]− (3), which reacts with [CpFe(C6H6)]+ and [(C4Me4)Co(C6H6)]+ under visible light irradiation to give closo-metallathiacarboranes 1-Cp-4-tBuNH-1,2,4-FeSCB9H9 (4) and 1-C4Me4-4-tBuNH-1,2,4-CoSCB9H9 (5) in 70% yields. At 110 °C, 4 undergoes extrusion of one boron atom, giving the 11-vertex compound closo-1-Cp-3-B(OH)2-1,2,3-FeSCB8H8 (6, 44%). According to DFT calculations, this process is initiated by nucleophilic attack of amine. The structures of 2, 4, 5, and 6 were confirmed by X-ray diffraction.

在质子海绵（Proton Sponge）存在下，叔丁基异腈（tBuNC）与巢式-6-硫杂壬硼烷（nido-6-SB9H11）发生反应，表观上经初始生成的巢式-7-叔丁基氨基-7,8-碳硫杂硼烷（nido-7-tBuNH2-7,8-CSB9H9，异构体1）的重排过程，得到巢式硫杂碳硼烷7-叔丁基氨基-7,9-碳硫杂硼烷（7-tBuNH2-7,9-CSB9H9，产物2）。对产物2进行去质子化处理，得到阴离子[巢式-7-叔丁基氨基-7,9-碳硫杂硼烷]−（[nido-7-tBuNH-7,9-CSB9H9]−，产物3）；该阴离子在可见光照射下，分别与[环戊二烯基（cyclopentadienyl，Cp）(苯)铁]阳离子（[CpFe(C6H6)]+）和[四甲基环丁二烯基（tetramethylcyclobutadienyl，C4Me4）(苯)钴]阳离子（[(C4Me4)Co(C6H6)]+）反应，以70%的收率得到闭式金属硫杂碳硼烷1-环戊二烯基-4-叔丁基氨基-1,2,4-铁硫杂碳硼烷（1-Cp-4-tBuNH-1,2,4-FeSCB9H9，产物4）与1-四甲基环丁二烯基-4-叔丁基氨基-1,2,4-钴硫杂碳硼烷（1-C4Me4-4-tBuNH-1,2,4-CoSCB9H9，产物5）。在110 ℃条件下，产物4发生脱硼反应，脱除一个硼原子，得到11顶点闭式化合物1-环戊二烯基-3-二羟基硼基-1,2,3-铁硫杂碳硼烷（closo-1-Cp-3-B(OH)2-1,2,3-FeSCB8H8，产物6，收率44%）。根据密度泛函理论（DFT）计算，该反应过程由胺基的亲核进攻引发。产物2、4、5与6的结构均通过X射线衍射（X-ray diffraction）得以确认。