Reactions of [ReOX3(PPh3)2] Complexes (X = Cl,Br) with Phenylacetylene and the Structures of the Products

Oxorhenium(V) complexes ReOX₃(PPh₃)₂] (X = Cl, Br) react with phenylacetylene under formation of complexes with ylide‐type ligands. Compounds of the compositions ReOCl₃(PPh₃){C(Ph)C(H)(PPh₃)}] ( 1 ), ReOBr₃(OPPh₃){C(Ph)C(H)(PPh₃)}] ( 2 ), and ReOBr₃(OPPh₃){C(H)C(Ph)(PPh₃)}] ( 3 ) were isolated and characterized by X‐ray diffraction. They contain a ligand, which was formed by a nucleophilic attack of released PPh₃ at coordinated phenylacetylene. The structures of the products show that there is no preferable position for this attack. Cleavage of the Re–C bond in 3 and dimerization of the organic ligand resulted in the formation of the {(PPh₃)(H)CC(Ph)}₂]²⁺ cation, which crystallized as its (ReOBr₄)(OReO₃)]^2– salt.