Mixed-valent diruthenium diphosphonate containing zigzag chain structure of {Ru2(hedp)2(SCN)}n4n−

Abstract This paper reports the crystal structure and magnetism properties of a novel mixed-valent diruthenium(II,III) complex, [C(NH 2 ) 3 ] 4 [Ru 2 (hedp) 2 (SCN)]·4H 2 O ( 1 ), where hedp represents 1-hydroxyethylidenediphosphonate. It shows a zigzag chain structure in which the paddlewheel diruthenium(II,III) dimers of Ru 2 (hedp) 2 3 − linked by SCN − bridges. The chains are stacked along the [011] direction with strong intra- and interchain hydrogen bonds. Magnetic studies show that significant antiferromagnetic exchanges are mediated between the [Ru 2 (hedp) 2 ] 3 − ( S  = 3/2) units through thiocyanate ion bridges. Structural analysis proves that the Ru Ru bond weakening ability is H 2 O  − − − − − .