An Atypically Bent Isocyanide at Iron In A Tetrapodal Penta‐Carbene Framework

Reduction of the previously reported Iron (III) complex Ph CC 4 Me FeCl with sodium naphthalide forms the square pyramidal complex Ph CC 4 Me Fe ( 1 ), cleanly in moderate yield with short reaction times. The related diamagnetic complex Ph CC 4 Me Fe(CN t Bu) ( 2 ) was prepared by addition of an equivalent of tert‐ butylisocyanide to a solution of 1 . XRD of 2 reveals a rare bent form of the isocyanide moiety with a C−N−C bond angle of 142.67(18)° consistent with sp 2 hybridization at the N‐atom while IR spectroscopy reveals an atypically broadened isocyanide stretch at ν CNR =1981 cm −1 ; taken together these metrics are demonstrative of the excellent donor ability of the dianionic penta‐carbene framework and point to a degree of metal‐to‐ligand π‐backbonding rarely seen at isocyanide complexes of iron.