A COMPARISON OF SOME COMPLEXES OF THE TYPE EQ-[MN2(CO)9L], WHERE L ISA CYCLIC CARBENE LIGAND WITH A 5-MEMBERED OR 6-MEMBERED RING AND THE MOLECULAR-STRUCTURES OF 2 COMPLEXES CONTAINING 6-MEMBERED CARBENE RINGS

Two new five-membered ring cyclic carbene complexes eq-[Mn2(CO)9L] (wh ere L = CCH2CH(CH3)CH2O or CC(CH3)2CH2CH2O) have been prepared and cha racterized. Thermal analysis and H-1/2D exchange experiments are compa red for several five- and six-membered ring cyclic carbene complexes o f the type eq-[Mn2(CO)9L]. The X-ray crystal structures of the six-mem bered ring carbene complexes eq-[Mn2(CO)9L] (where L = CCH2CH2CH2CH2O and CCH2CH2CH2CH(CH3)O) have been determined and are compared with the known structures of the related five-membered ring complexes.