New [Mo(eta3-allyl)(CO)2L3]+ complexes with monodentate or tridentate nitrogen-donor ligands

Cationic complexes Mo(eta(3)-allyl)(CO)2L3]+ (L3 = either nitrogen-donor tridentate ligand or three monodentate ligands) were prepared in high yield and under mild conditions using as precursors either the triflato complex Mo(eta(3)-allyl)(OTf)(CO)2(NCMe)2] or the combination of the chloro complex Mo(eta(3)-allyl)Cl(CO)2(NCMe)2] and the salt NaBAr'(4)(Ar'= 3,5-bis(trifluoromethyl)phenyl). The tridentate ligands employed were 2,2':6',2'-terpyridine (terpy) and cis,cis-1,3,5-cyclohexanetriamine (CHTA), whereas the monodentate ligands imidazole (im) and 3,5-dimethylpyrazole (dmpz) were chosen. In order to stabilize the labile intermediates, an excess of acetonitrile was used in most of the syntheses. However, the pyrazole complex was prepared through a nitrile-free route to avoid reactions at the coordinated nitrile. The solid state structures of Mo(eta(3)-methallyl)(CO)2(terpy)]OTf (2), Mo(eta(3)-methallyl)(CO)2(CHTA)]BAr'4 (3), Mo(eta(3)-methallyl)(CO)2(NCMe)3]BAr'4 (4), Mo(eta(3)-allyl)(CO)2(im)3]OTf (5) and Mo(eta(3)-allyl)(CO)2(dmpz)3]BAr'4 (6) were determined by means of single-crystal X-ray diffraction.