Synthesis and coordination chemistry of pyrimidine-substituted phosphine ligands

Reaction of PPh2H with UrI (Ur = uracil) in the presence of Pd(OAc)(2) affords PPh(2)Ur. In the solid state, PPh(2)Ur crystallises as a methanol solvate in the monoclinic space group P2(1)/c. Reaction of PPh(2)Ur with CuI in dry and deoxygenated THF solution results in the formation of [Cu-4(mu(3)-I)(4)(PPh(2)Ur)(4)]. A single crystal X-ray diffraction study demonstrated that this species contains a distorted tetrahedral core of copper atoms, with facially-capping iodides. The uracil groups in the clusters are engaged in hydrogen bonding to groups on neighbouring molecules to form an extended array. A similar reaction between PPh(2)Ur and CuI in unpurified THF allows for the isolation of the phosphine oxide P(O)PPh(2)Ur. The synthesis of the benzyl-protected phosphine PPh(2)Ur(P) is also described [Ur(P) = 2,4-bis(benzyloxy)pyrimidine]. Reaction of PPh(2)Ur(P) with [Ru(eta(5)-C5H5)(NCMe)(3)]PF6 allows for isolation of [Ru(eta(5)-C5H5)(NCMe)(PPh(2)Ur(P))(2)]PF6. (C) 2011 Elsevier B.V. All rights reserved.