Clusters as ligands: Synthesis, structure and coordination chemistry of ruthenium clusters derived from 4- and 5-ethynyl-2,2′-bipyridine

The reaction of [Ru3(CO)10(μ-dppm)] (1) with 4-ethynyl-2,2′-bipyridine (2) or 5-ethynyl-2,2′-bipyridine (3) affords the Ru3C2 clusters [Ru3(μ-H)(μ3-C2bpy)(CO)7(dppm)] (bpy = 4-bpy, 4 (22%); bpy = 5-bpy, 5 (55%)). Complexes 4 and 5 have been fully characterised by NMR spectroscopy, with 2D-COSY methods being used to aid 1H NMR assignments, and single crystal X-ray diffraction. The pendant bipyridyl moiety presents as a site for further reaction using the ‘Tinkertoy’ approach, and subsequent reactions of 4 and 5 with PdCl2(NCPh)2 affords the bimetallic complexes [Ru3(μ-H){μ3-C2bpy(κ2-N′,N–PdCl2)}(CO)7(dppm)] bpy = 4-bpy, 6 (55%); bpy = 5-bpy, 7 (35%)).