Synthesis and Dynamics of Ferrous Polychalcogenides [Fe(E x )(CN) 2 (CO) 2 ] 2- (E = S, Se, or Te).

Elemental chalcogens react with [Fe(CN) 2 (CO) 3 ] 2- to give the following ferrous derivatives: [K(18-crown-6)] 2 [Fe(S 5 )(CN) 2 (CO) 2 ], [K(18-crown-6)] 2 [Fe(S 2 )(CN) 2 (CO) 2 ], [K(18-crown-6)] 2 [Fe(Se 4 )(CN) 2 (CO) 2 ], [K(18-crown-6)] 2 [Fe(Te 2 )(CN) 2 (CO) 2 ], and (NEt 4 ) 2 [Fe(Te 2 )(CN) 2 (CO) 2 ]. While these complex anions crystallized in a single stereochemistry (i.e., trans dicyanides or cis dicyanides), they isomerize in solution upon irradiation. The results are benchmarked by the corresponding studies on benzyl thiolate [K(18-crown-6)] 2 [Fe(SBn) 2 (CN) 2 (CO) 2 ].