Synthesis and structure of bis(methylsulfanyl) derivatives of iron bis(dicarbollide)

Bis(methylsulfanyl) derivatives of iron(II) bis(dicarbollide) [8,8'-(MeS)2-3,3'-Fe(1,2-C2B9FH10)(2-) (4(2-), [4,4'-(MeS)2-3,3'-Fe(1,2-C2B9I-tio)2](2-) (5(2-)), and [4,7'-(MeS)(2)-3,3'-Fe(1,2-C2B9FH10)212-(62-) were prepared by the treatment of the corresponding dimethylsulfonium derivatives 1-3 with potassium butylthiolate. Their oxidation by air in aqueous solution results in the corresponding derivatives of iron(III) bis(dicarbollide) [8,8'-(Me5)2-3,3'-Fe(1,2-C239I-tio)21 (7), [4,4'4MeS)2-3,3'-Fe(1,2-C2B9H10)21-(8-) and [4,7'(MeS)2-3,3'-Fe(1,2-C2B9I-tio)2i (9-). The structures of (Bu4N)(2)[8,8'-(MeS)2-3,3'-Fe(1,2-C2B9H10)2(-) and (Me4N)[4,7'-(MeS)2-3,3'-Fe(1,2-C2B9H10)2] were determined through single-crystal X-ray diffraction. In the solid state, the rotation of the dicarbollide ligands with respect to each other is hampered due to formation of weak intramolecular CFI.-S(Me) hydrogen bonds between the ligands resulting in stabilization of transoid-conformation in the case of 8,8'-isomer and gauche-conformation in the case of 4,4' and 4,7'-isomers. The synthesized bis(methylsulfanyl) derivatives of iron bis(dicarbollide) can be considered as a versatile platform for design of molecular switches. (C) 2018 Elsevier B.V. All rights reserved.