Crystal structure of a Pd4 carbonyl triphenylphosphane cluster [Pd4(CO)5(PPh3)4]·2C4H8O, comparing solvates

Attempts to synthesize Au–Pd heterometallic compounds from homonuclear palladium or gold complexes, [Pd(PtBu2)2] and [Au(PPh3)Cl] in a tetrahydrofuran (THF) solution under a CO atmosphere resulted in a homonuclear Pd cluster, namely pentakis(μ-carbonyl-κ2C:C)tetrakis(triphenylphosphane-κP)tetrapalladium(5 Pd—Pd) tetrahydrofuran disolvate, [Pd4(CO)5(C18H15P)4]·2C4H8O. The complex molecule lies on a twofold rotation axis. The crystal structure is described in relation to the CH2Cl2 solvate previously determined by our group [Willocq et al. (2011). Inorg. Chim. Acta, 373, 233–242], and in particular to the desolvated structure [Feltham et al. (1985). Inorg. Chem. 24, 1503–1510]. It is assumed that the title compound transforms into the latter structure, upon gradual loss of solvent molecules. In the title compound, the symmetry-unique THF solvent molecule is linked to the complex molecule by a weak C—H...O hydrogen bond. Contributions of disordered solvent molecules to the diffraction intensities, most likely associated with methanol, were removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18] algorithm