Synthesis and crystallographic characterization of thiazolyl and thiazolinylidene complexes of cyclopentadienyliron(II)

Abstract

The consecutive reaction of FeCl₂ with bis(diphenylphosphino)methane or 1,2-bis(diphenylphosphino)ethane, benzothiazol-2-yllithium or 4-methylthiazolyllithium and cyclopentadiene affords thiazolinylidene(thiazolyl) complexes which contain only one co-ordinated phosphorus atom. An X-ray crystal structure determination of one of these, [Fe(η⁵-C₅H₅)([graphic omitted]-o)([graphic omitted]-o)(dppe)], has revealed a metal–carbene carbon bond length of 1.889(3)Å and a hydrogen bond between the nitrogen atoms in the two neighbouring carbene and benzothiazolyl ligands. Cationic thiazolinylidene complexes form when the products from the reaction between [Fe(η⁵-C₅H₅)(CO)₂Cl] and benzothiazol-2-yllithium or 4-methylthiazolyllithium are acidified with trifluoromethanesulfonic acid. A single crystal X-ray structure determination of [Fe(η⁵-C₅H₅)(CO)₂{[graphic omitted]}]CF₃SO₃·0.5H₂O showed a metal–carbene carbon bond length of 1.947(3)Å which is longer than all the Fe–C(carbonyl) distances (average 1.768 Å).