Preparation and NMR study of trimetallic complexes of platinum and tungsten bridged by 4-pyridylacetylide and a binuclear complex of rhodium and tungsten bridged by 2-(4-pyridyl)thiazole-4-carboxylate (PTC): structure of [(Ph3P)2Rh(H)2(μ-PTC)W(CO)4(P(4-MeC6H4)3)]

The complexes [(dppp)Pt{(mu-C2C5H4N)W(CO)(4)(PR3)}(2)] (dppp = Ph2P(CH2)(3)PPh2; PR3 = PPh3 (1), P(4-XC6H4)(3) (X = Me (2), OMe (3), F (4)) P(NMe2)(3) (5)) were prepared from [(dppp)Pt(C2C5H4N)(2)] and cis-[W(CO)(4)(PR3)(CH3CN)] and were characterized by H-1, C-13, N-15, P-31, W-183 and Pt-195 NMR spectroscopy. The complex [(Ph3P)(2)Rh(H)(2)(mu-PTC)W(CO)(4)(P(4-MeC6H4)(3))] (6) was prepared similarly, from [(Ph3P)(2)Rh(H)(2)(PTC)] (thiazole nitrogen and carboxylate oxygen attached to the metal) and cis-[W(CO)(4)(P(4-MeC6H4)(3))(CH3CN)] and was characterized by NMR (H-1, C-13, N-15, P-31, Rh-103 and W-183) and by X-ray crystallography, which shows pi-pi interactions between the bridging pyridyl and a phenyl group from a phosphine on each metal. In complexes 1-5, there is little variation in the platinum chemical shift, indicating that electronic influences through the pyridylacetylide bridge are minimal. A bimetallic complex of rhodium and tungsten bridged by 2-(4-pyridyl)-thiazole-4-carboxylate is reported together with an NMR spectroscopic study of a series of trinuclear complexes of platinum and tungsten bridged by 4-pyridylacetylide.