Molecular Copper(II) Complexes Derived from Phosphonoacetic Acid: Crystal Structures and Magnetic Behavior

The syntheses, structural characterization, and magnetic behavior of five new copper(II) complexes derived from phosphonoacetic acid, H 2 O 3 PCH 2 CO 2 H, with the formulae [Cu{(py) 2 C(OH) 2 }](HO 3 PCH 2 CO 2 H) 2 ( 1 ), [Cu 2 (HO 3 PCH 2 CO 2 ) 2 {(py) 2 C(OCH 3 )OH} 2 ] ( 2 ), [Cu 2 (HO 3 PCH 2 CO 2 ) 2 (bpy) 2 ] ( 3 ), [Cu 4 (O 3 PCH 2 CO 2 ) 2 (5‐dmbpy) 4 (H 2 O) 4 ](NO 3 ) 2 ( 4 ), and [Cu 4 (O 3 PCH 2 CO 2 ) 2 (5‐dmbpy) 4 (H 2 O) 4 ](ClO 4 ) 2 ( 5 ) are reported. [H 2 O 3 PCH 2 CO 2 H = phosphonoacetic acid, (py) 2 C(OH) 2 = bis(2‐pyridyl)methanediol, {(py) 2 C(OCH 3 )OH} = bis(2‐pyridyl)methoxymethanol, bpy = 2,2′‐dipyridyl, 5‐dmbpy = 5,5′‐dimethyl‐2,2′‐dipyridyl, terpy = 2,2′:6′,2″‐terpyridine]. Complex 1 is a mononuclear compound with hydrogenphosphonateacetic acid in its monoanionic form, complexes 2 and 3 are dinuclear compounds with hydrogenphosphonoacetate(2–) bridging ligands, and complexes 4 and 5 are tetranuclear compounds with phosphonoacetate(3–) bridging ligands. The magnetic properties of polynuclear complexes 2 – 5 are reported.