Synthesis, crystal structure and magnetic properties of an unexpected new coordination Cu(II) compound, containing two different phosphato-bridged dinuclear units; [Cu2(phen)2(μ-H2PO4-O,O′)2(H2PO4)2][Cu2(phen)2(μ-H2PO4-O,O′)(μ-H2PO4-O)(μ-HPO4-O)]2(H2O)9(p

The crystal structure of a copper(II) complex containing the ligand 1,10-phenanthroline (phen) with mono- and di-dentate image and monodentate image oxoanions, [Cu2(phen)(μ-H2PO4-O,O′)2(H2PO4)2][Cu2(phen)2(μ-H2PO4-O,O′)(μ-H2PO4-O)(μ-HPO4-O)]2(H2O)9, is reported and determined by X-ray crystallography. Two crystallographically independent dinuclear units with different bridging properties of (di)hydrogenphosphato anions are found in this compound. The two Cu(II) ions in the first unit, [Cu2(phen)(μ-H2PO4-O,O′)2(H2PO4)2], are bridged by two didentate bridging dihydrogenphosphato monoanions and also contains two non-bridging monovalent dihydrogenphosphato anions. The geometry of the Cu(II) ions is square pyramidal with a Cu–Cu distance of 5.043(3) Å. The two Cu(II) ions in the second unit, [Cu2(phen)2(μ-H2PO4-O,O′)(μ-H2PO4-O)(μ-HPO4-O)], are bridged by three different hydrogenphosphate anions; a didentate bridging dihydrogenphosphate monoanion, a monodentate dihydrogenphosphate bridging monoanion and a monodentate hydrogenphosphate dianion. This bridging mode is unique and has not been reported so far for dinuclear Cu(II) compounds. The geometry of the Cu(II) ions in this second unit is distorted square pyramidal and the Cu–Cu distance is 3.074(3) Å. The magnetic susceptibility measurement (5–300 K) have been fitted with two different J values. A weak antiferromagnetic interaction between the Cu ions in one dinuclear unit with J1 = −8.2 cm−1 and a very weak ferromagnetic interaction between the Cu ions in the other dinuclear unit with J2 = 0.96 cm−1, allow an acceptable fit.