MOLYBDENUM CARBONYL-COMPLEXES OF PENDANT-ARM POLYAZAMACROCYCLES

Molybdenum hexacarbonyl reacted with the pendant-arm macrocycles 10-me thyl-1,4,8, 12-tetraazacyclopentadecane-10-amine (L-1) and 6,13-dimeth yl-1,4,8,11-tetraazacyclotetradecane-6, 13-diamine (L-2) in the absenc e of air to form complexes fac-[MoL1(CO)(3)] and [Mo2L2(CO)(8)] respec tively. The mononuclear complex has the macrocycle bound in a tridenta te manner, including the pendant primary amine, whereas the dinuclear complex exhibits a bridging bis(didentate) co-ordination mode, again i nvolving the pendant primary amines. Structures have been defined by c rystal structure analyses. The preferential binding of the pendant pri mary amines rather than additional secondary amines parallels similar behaviour observed earlier with some mercury(II) and rhodium(III) comp lexes, and points to the important general role of this pendant, despi te being fused directly to the macrocyclic ring, in metal-ion binding.