REACTION OF MO=MO DOUBLY-BONDED COMPLEXES (ETA(5)-RC5H4)(2)MO-2(CO)(2)(MU-SPH)(2) WITH ELEMENTAL SELENIUM - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF SOME NOVEL SULFUR SELENIUM QUADRUPLY-BRIDGED MOLYBDENUM COMPLEXES/

The reaction of Mo=Mo doubly-bonded (eta(5)-RC5H4)(2)Mo-2(CO)(2)(mu-SP h)(2) (R = MeO2C, EtO2C) with elemental selenium in toluene at reflux results in formation of a series of sulfur/selenium quadruply-bridged complexes ns/anti-(eta(5)-RC5H4)(2)Mo-2(mu-Se)(2)(mu-SPh)(2) (1a, R = MeO2C; 2a, R = EtO2C), ans/syn-(eta(5)-RC5H4)(2)Mo-2(mu-Se)(2)(mu-SPh) (2) (1b, R = MeO2C; 2b, R = EtO2C), and cis/syn-(eta(5)-RC5H4)(2)Mo-2( mu, eta(2):eta(2)- Se-2)(mu-SPh)(2) (1c, R = MeO2C;2c, R = EtO2C) in 5 8% and 53% overall-yields, respectively. The structures of all these n ew products have been characterized by elemental analysis, IR,H-1 NMR and MS,spectroscopies, as well as for 2c by X-ray crystallography. (C) 1998 Elsevier Science Ltd All rights reserved.