Some reactions of bis(tricarbonyl-π-cyclopentadienylchromium)-mercury and related compounds

Abstract

The mercury–chromium complex [(π-C₅H₅)Cr(CO)₃]₂Hg reacts with HgX₂(X = Cl, Br, or l), Br₂, l₂, and various phosphorus ligands L [L = Ph₃P, (PhO)₃P, and (MeO)₃P] to give (π-C₅H₅)Cr(CO)₃HgX, (π-C₅H₅)Cr(CO)₃Br, (π-C₅H₅)Cr(CO)₃I, and [(π-C₅H₅)Cr(CO)₂L]₂Hg respectively. All are markedly less stable than their molybdenum and tungsten analogues. The reactions of [(π-C₅H₅)W(CO)₃]₂Hg with l₂ and Br₂ have also been investigated. The first mole of halogen splits one W–Hg bond only to give a mixture of (π-C₅H₅)W(CO)₃X and (π-C₅H₅)W(CO)₃HgX [X = Br or I]. Excess halogen gives (π-C₅H₅)W(CO)₃I and (π-C₅H₅)W(CO)₂Br₃ as the sole products.