Reactivity of the Metal→BX₃ Dative σ-Bond: 1,2-Addition Reactions of the Fe→BX₃ Moiety of the Ferraboratrane Complex [κ⁴-B(mim^{Bu^t})₃]Fe(CO)₂

The ferraboratrane [κ4-B(mimBut)3]Fe(CO)2 (mimBut = 2-mercapto-1-tert-butylimidazolyl), the first example of a complex which possesses a retrodative (i.e., metal-to-ligand) Fe→B bond, is obtained via reaction of the tris(2-mercapto-1-tert-butylimidazolyl)hydroborato complex [TmBut]FeCl with LiCH2SiMe3 followed by treatment with CO. Significantly, [κ4-B(mimBut)3]Fe(CO)2 exhibits novel reactivity towards a variety of reagents that results in eradication of the Fe→B bond via a formal 1,2-addition process and the formation of B-functionalized tris(mercaptoimidazolyl)borate derivatives, [XTmBut]FeY.铁硼杂笼状配合物[κ⁴-B(mimBut)₃]Fe(CO)₂（其中mimBut为2-巯基-1-叔丁基咪唑基，2-mercapto-1-tert-butylimidazolyl）是首个具备反馈型（即金属至配体）Fe→B键的配合物，可由三(2-巯基-1-叔丁基咪唑基)氢硼酸盐配合物[TmBut]FeCl与三甲基硅基甲基锂（LiCH₂SiMe₃）反应后，再经一氧化碳（CO）处理制得。值得注意的是，[κ⁴-B(mimBut)₃]Fe(CO)₂对多种试剂展现出新颖反应性，该反应通过形式上的1,2-加成过程断裂Fe→B键，并生成B-官能化三(巯基咪唑基)硼酸盐衍生物[XTmBut]FeY。