Synthesis, structure and magnetic properties of a binuclear Co(II)-pyrophosphate complex, [Co2(phenanthroline-dione)4(P2O7)]

Abstract A series of Co(II)-1,10-phenanthroline-5,6-dione (phendione) complexes were prepared as scaffolds for the incorporation of pyrophosphate or methylenediphosphonate bridging ligands. Minor modifications in reaction conditions yielded the mononuclear complexes [Co(phendione)(H 2 O) 4 ](SO 4 )•2H 2 O ( 1 ) and methylenediphosphonate complex [Co(phendione)(H 2 O 3 PCH 2 PO 3 H)(H 2 O) 2 ]Cl•3H 2 O ( 2 ). A bridged binuclear complex, [Co 2 (phendione) 4 (P 2 O 7 )]∙nH 2 O ( 3 ) was also prepared and structurally characterized. The magnetic properties of 3 were investigated.