C(sp3)–N(sp) Bond Cleavage of Isocyanides at a Cationic [CCH] Subunit in a Bisdisphenoidal Eight-atom Tetrairon–Tetracarbon Cluster

Abstract

Reaction of [(η5-C5H4Me)4Fe4(HCCH)(HCC–NC4H4N)](PF6)2 (1) with tert-butyl isocyanide led to C(sp3)–N(sp) bond activation to give [(η5-C5H4Me)4Fe4(HCCH)(HCC–CN)](PF6) (2). The resulting tert-butyl cation was trapped as the adduct with pyrazine. Reactions of 1 with 2,6-dimethylphenyl isocyanide and cyclohexyl isocyanide led to the coordination of the isocyanides to the cationic [CCH] subunit. Thermolysis of [(η5-C5H4Me)4Fe4(HCCH)(HCC–CNCy)](PF6)2 (6) yielded 2.

Activation of Isocyanides and Hydrosilanes by a Cationic [CCH] Subunit in a Tetrairon–Tetracarbon Cluster

“…In the reactions with cyclohexyl and benzyl isocyanides, isocyanide adducts [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)(HCC-CNR)]-(PF 6 ) 2 (R = Cy (5), CH 2 Ph (6)) were obtained and further transformed to 2 (70°C, 10 h for 5; RT, 120 h for 6). The reactions of 1 with aryl isocyanides such as 2,6-dimethylphenyl and 2,4,6-tri-tert-butylphenyl isocyanides yielded thermally stable [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)(HCC-CNAr)](PF 6 ) 2 (Ar = 2,6-Me 2 C 6 H 3 (8), 2,4,6-t Bu 3 C 6 H 2 (9)). The SiH bonds of R 3 SiH (R = Et, Ph), Ph 2 SiH 2 , and PhSiH 3 were activated to give [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH) 2 ](PF 6 ) together with the corresponding fluorosilanes.…”