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, H2O3PCH2CO2H, with the formulae [Cu{(py)2C(OH)2}](HO3PCH2CO2H)2 (1), [Cu2(HO3PCH2CO2)2{(py)2C(OCH3)OH}2] (2), [Cu2(HO3PCH2CO2)2(bpy)2] (3), [Cu4(O3PCH2CO2)2(5‐dmbpy)4(H2O)4](NO3)2 (4), and [Cu4(O3PCH2CO2)2(5‐dmbpy)4(H2O)4](ClO4)2 (5) are reported. [H2O3PCH2CO2H = phosphonoacetic acid, (py)2C(OH)2 = bis(2‐pyridyl)methanediol, {(py)2C(OCH3)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. Five new copper(II) complexes derived from the anionic forms of phosphonoacetic acid are prepared. Four of these complexes are polynuclear copper(II) complexes, in which the above‐mentioned anionic ligands act as bridging ligands in different coordination modes, and the other is a mononuclear compound. The magnetic behavior of the polynuclear compounds is studied.