Diphenyldichalcogenide complexes of iron, chromium and rhenium carbonyls

The substitution of a labile THF ligand in Cr(CO)5(THF) by the Ph2Se2 molecule provided the monomeric complex Cr(CO)5(Ph2Se2) (I). The similar diiodo-tricarbonyl-iron complex (CO)3FeI2(Ph2Se2) (II) (along with [(CO)3Fe(μ-SePh)3Fe(CO)3]+(I5)− (III) as a by-product) was separated upon the treatment of “phenylselenyl iodide” [PhSeI] with iron pentacarbonyl, Fe(CO)5. Complex II is isostructural with the known tellurium-containing analogue, (CO)3FeI2(Te2Ph2). The latter have provided the dimeric tellurophenyl bridged iodo-tricarbonyl-iron complex [(CO)3IFe(μ-TePh)]2 (IV) under action of the excess of Fe(CO)5. Its bromide analogue [(CO)3BrFe(μ-TePh)]2 (V) was prepared upon the treatment of PhTeBr with the excess of Fe(CO)5. The reaction of [PhSeI] with Re(CO)5Cl afforded only [(CO)6Re2(μ-I)2(μ-Se2Ph2)] (VI) in contrast to the (CO)3Re(PhTeI)3(μ3-I) formation in similar known reaction of [PhTeI]. The molecular and crystal structures of I–VI is discussed.