LIGAND-INDUCED P-2 COUPLING TO AN ACYCLIC P-4 LIGAND

The further terminal coordination of M(CO)(5) (M = Cr, Mo W) to [(Cp'' 'Co)(2)(mu-eta(2:2)-P-2)(2)] (1), Cp''' = 1,2,4-tBu(3)C(5)H(2), afford s the polynuclear cobalt complexes Co)(2)(mu(3(4))-eta(4:4:1:(1))-P-4) {M(CO)(5)}(n)], n = 1; M = Cr (2a), Mo (2b), W (2c) and n = 2, M = W ( 3). The X-ray crystal structure analyses as well as low-temperature P- 31-NMR studies show that in 1 the two P-2 ligands are rectangularly or iented while in 2b, 2c, and 3 they are coupled to an acyclic, trapezoi dally arranged P-4 chain.