Complexes of 1,1,2-tris(diphenylphosphino)ethane with Group 6 metal carbonyls

Abstract

The preparation of (Ph₂P)₂CHCH₂PPh₂(tppe) and its reactions with [M(CO)₆](M = Cr, Mo, or W) are described. In the 1 : 1 complexes [M(CO)_n(tppe)](n= 3–5) there are five possible modes of co-ordination, and all have been identified although indirect synthetic routes are required for several. The phosphours-31 n.m.r. chemical shifts and coupling constants show consistent patterns of behaviour that are interpreted in terms of chelate ring formation and of through-the-metal and ligand backbone contributions. Molybdenum-95 and tungsten-183 n.m.r. data are also presented.