Heteromultimetallic Transition Metal Complexes Based on Unsymmetrical Platinum(II) Bis-Acetylides

The synthesis of a unique series of heteromultinuclear transition metal complexes with up to seven different metal atoms is reported by using consecutive synthesis methodologies including metathesis, dehydrohalogenation, and carbon−carbon cross-coupling reactions. In these compounds the metals Ti, Fe, Ru, Os, Re, Pt, and Cu are connected via carbon-rich bridging units comprising 1,3,5-triethynylbenzene and 2,2′-bipyridyl-5-yl. These molecules have been characterized by elemental analysis, IR and NMR spectroscopy, and ESI-TOF mass spectrometry. The main structural feature of these compounds is an unsymmetrical trans -configurated platinum(II) bis-acetylide unit. The structure of 1-(FcC≡C)-3-[( t Bu 2 bpy)(CO) 3 ReC≡C]-5-[ trans -(Ph 3 P) 2 (RcC≡C)PtC≡C]C 6 H 3 ( 3 ) and 1,3-[(Ph 3 P) 2 (η 5 -C 5 H 5 )OsC≡C] 2 -5-[(CO) 3 (Cl)Re(bpyC≡C)]C 6 H 3 ( 18 ) (Fc = (η 5 -C 5 H 5 )(η 5 -C 5 H 4 )Fe; Rc = (η 5 -C 5 H 5 )(η 5 -C 5 H 4 )Ru; t Bu 2 bpy = 4,4′-di- tert -butyl-2,2′-bipyridyl; bpy = 2,2′-bipyridyl-5-yl) in the solid state is reported. Both compounds are characterized by the central 1,3,5-triethynylbenzene core, bridging the individual transition metal building blocks. These organometallic fragments show thereby typical structural properties. The appropriate metal acetylide moieties are, as expected, found in a linear arrangement with representative M−C and C≡C bond distances.