Tetrazolate rhodium(I) complexes. Crystal structures of the trinuclear complexes [Rh3(µ3-ttz)(µ-Cl)Cl(cod)2(CO)2](ttz = tetrazolate, cod = cyclo-octa-1,5-diene) and [Rh3(µ3-ttz)(µ-Cl)Cl(CO)6], an unusual example of metal–metal interactions

Abstract

Homo- and hetero-bridged binuclear complexes of general formulae [Rh₂(µ-ttz)₂(L₂)₂][ttz = tetrazolate, L₂= diolefin or (CO)₂] and [Rh₂(µ-ttz)(µ-X)L₂L′₂][X = Cl, L₂= L′₂= diolefin; X = N₃, L₂= L′₂= diolefin, L₂= cyclo-octa-1,5-diene (cod), L′₂=(CO)₂] have been prepared. The heterobridged complexes, having unco-ordinated N atoms from the tetrazolate group, react with [Rh₂(µ-Cl)₂(L″₂)₂](2 : 1 molar ratio)[L″₂= cod or (CO)₂] to give trinuclear compounds of general formula [Rh₃(µ₃-ttz)(µ-X)ClL₂L′₂L″₂](X = Cl or N₃). The latter complexes can also be obtained by reaction of [Rh₂(µ-ttz)₂(L₂)₂] with [Rh₂(µ-Cl)₂(L′₂)₂](1 : 2 molar ratio). X-Ray crystallographic studies of the complexes [Rh₃(µ₃-ttz)(µ-Cl)Cl(cod)₂(CO)₂](12) and [Rh₃(µ₃-ttz)(µ-Cl)Cl(CO)₆](13) show them to contain trinuclear units, with bridging Cl atoms and tetrazolate groups. In complex (13) the units pack in the crystal with infinite chains, through Rh ⋯ Rh interactions of 3.457(2), 3.229(2), and 3.399(2)Å. In compound (12) the complex consists only of two units, related by a symmetry centre with a Rh ⋯ Rh distance equal to 3.519(2)Å.