Crystal structure and molecular stereochemistry of polymeric Cu2(DMP)4(DMSO) as a platform for phosphate diester binding

Treatment of a solution of CuCl₂ in dimethyl phosphate (DMP) in an inert solvent under nitrogen atmosphere resulted in a light blue fluorescence powder. Slow evaporation of H₂O‐DMSO solution of this powder led to the formation of blue‐sky crystals of a new polymeric Cu(II) complex, with a unit cell composed of Cu₂(DMP)₄(DMSO), (1). The crystal and molecular structure of the complex was established crystallographically. Compound (1) crystallizes in the monoclinic space group P2₁/n with a = 12.8920(11)Å, b = 13.1966(11)Å, c = 14.7926(13)Å, α = 90°, β = 98.943(2)°, γ = 90° and Z = 4. A square pyramidal environment for the metal center is established by coordination of oxygen atoms of four bridging DMP ligands in the basal positions and a tri‐centered oxygen atom of DMSO in the apical disposition. The sixth position is also affected by a weak interaction with the sulfur atom of DMSO. The phosphorous atom in the bridging DMP is arranged in a deformed tetrahedron with gg conformation for methyl esters with C_2v symmetry. Accordingly, the angles of methoxy substituents are unexpectedly smaller than the bridging oxygens, and synchronous z‐in and z‐out distortions are suggested for DMP anion. The oxygen atom of SOCuCu’ fragment derived from DMSO, functions as a tri‐centered nuclei lie almost in a trigonal triangle environment. This study helps provide further insights into the binding nature of phosphate esters to the active sites of enzymes, which catalyze phosphoryl transfer reactions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)