Reactivity of [SeFe₃(CO)₉]^2- with Electrophiles:  Formation of [SeFe₂Ru₃(CO)₁₄]^2-, [SeFe₃(CO)₉(μ-HgI)]^-, Fe₂(CO)₆(μ-SeCHPhSe), and Se₂Fe₂(CO)₆(μ-CH₂)₂

Abstract

The reactions of the tetrahedral cluster [SeFe3(CO)9]2- with some transition-metal complexes and organic halides were investigated. The mixed-metal cluster [Et4N]2[SeFe2Ru3(CO)14] (1) was obtained from the reaction of [Et4N]2[SeFe3(CO)9] with Ru3(CO)12 in acetone. Further reaction of [Et4N]2[SeFe3(CO)9] with HgI2 produces the HgI-bridged cluster [Et4N][SeFe3(CO)9(μ-HgI)] (2). While [SeFe3(CO)9]2- reacts with CHPhCl2 to produce the CHPh-bridged cluster Fe2(CO)6(μ-SeCHPhSe) (3), treatment with CH2I2 forms the major product Se2Fe2(CO)6(μ-CH2)2 (4). Complex 1 displays an octahedral metal core with a μ4-Se atom and two carbonyl groups bridging the Ru−Ru and Ru−Fe bonds. Cluster 2 consists of a SeFe3 core with a HgI fragment bridging one Fe−Fe bond, and cluster 3 exhibits a Se2Fe2 butterfly geometry with the wingtip linked by a CHPh moiety. On the other hand, cluster 4 contains a planar Se2Fe2 moiety with two CH2 groups bridging the two Se−Fe bonds. Complexes 1−4 have been fully structurally characterized by spectroscopic methods and X-ray diffraction analyses. This paper describes the formation of four different types of clusters from the reactions of [SeFe3(CO)9]2- with electrophiles and discusses the role of [SeFe3(CO)9]2- and the incoming electrophiles.