Crystal structure of [Cu4(pytp)2(SO4)2(H2O)10](SO4)2 · 4H2O. A tetranuclear copper(II) complex with a new asymmetric ligand, pytp*, as a bridge

A new asymmetric bridge ligand, pytp, was prepared and characterized systematically by f.t.i.r., u.v.–vis., 1H-n.m.r. and by FAB-MS spectroscopy. A tetranuclear CuII complex [Cu4(pytp)2(SO4)2(H2O)10](SO4)2·4H2O (1) was prepared and characterized by elemental analysis and u.v.–vis. spectroscopy. A crystal structure analysis indicates that there are two different coordination spheres in (1) and that two of the copper centers are bridged by two μ2-SO4 entities, creating a most unusual sulphate bridge.