A MULTINUCLEAR NMR INVESTIGATION OF SOME TRICARBONYL MOLYBDENUM(0) COMPLEXES OF GROUP-14 SUBSTITUTED ARENE LIGANDS

Several molybdenum tricarbonyl complexes of the type [Mo(CO)(3)(arene) ] [arene=C(6)H(5)EMe(3) (E=C, Si, Ge, Sn), 4-MeC(6)H(4)EMe(3) (E-Si, S n), 1,4-Me(3) SiC(6)H(4)SiMe(3), 4-MeOC(6)H(4)SnMe(3), Me(3)SnBz, 1,3, 5-R(3)C(6)H(3) (R = Me, Pr-i), C(6)H(5)R (R = Bu(iso), Bu(sec), Pr-ll, SiH3, Si(Me)H-2, Si(Me)(2)H)] have been synthesized by the reaction o f Mo(CO)(3)(py)(3) with arene in the presence of BF3 . Et(2)O. These c omplexes have been studied by multinuclear (H-1, C-13, Mo-95) NMR and IR spectroscopies. The Mo-95 NMR chemical shifts, which span the range from -1905 to -2092 ppm, are markedly influenced by the nature of the substituents on the arene ring.