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

Abstract

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.

CuII Frameworks from Di‐2‐pyridyl Ketone and Benzene‐1,3,5‐triphosphonic Acid

“…Complexes 1 and 2 join a small family of di-2-pyridyl ketone/phosphonate Cu II and Ni II complexes. [26,[33][34][35][36] …”

“…[32] Following this approach, we isolated a series of 1D, 2D and 3D coordination polymers and hydrogenbonded frameworks in which the various forms of the py 2 CO gave rise to the formation of dinuclear Cu II complexes that served as nodes and, in combination with the bridging bi-or polycarboxylates, led to extended frameworks. Extending this approach to bridging ligands beyond bi/polycarboxylates, poly- [26,[33][34][35][36] Results and Discussion…”

Synthesis, Crystal Structure and Characterization of Two Novel One- and Two-Dimensionally Polymeric Copper(II) Phosphonoacetates

“…[ 18] The three forms of the phosphonoacetate anion appear in e.g. M[HOOC(CH2)PO3H]2 2H2O (M = Mn, Co, Zn, Cu) [ 19 ] , UO2[HOOC(CH2)PO3] [ 20 ] , Cu2[OOC(CH2)PO3H]2(bpy)2 [ 21 ] , and Mn3[OOC(CH2)PO3]2 [ 22 ] . The connection between Cu 2+ and phosphonoacetate anions leads to coordination polymers with one-, two and three-dimensional structural features.…”

“…The structures of Cu(II) phosphonoacetates can be modified using additional N-donor ligands. [21] Herein, we report on a novel two-dimensionally polymeric copper(II) hydrogenphosphonoacetate dihydrate and a onedimensionally polymeric copper(II) phosphonoacetate pentahydrate.…”

Molecular Switching of Copper Complexes with Quaterpyridine

“…In the presence of polypyridines, copper(I) ions form both σ and back‐bonding interactions, which enables metal‐to‐ligand charge transfer (MLCT) . Complexes of copper(II), well known for their paramagnetic properties (d 9 shell), interact with ligands exclusively through σ bonds . Their excitation results in luminescence quenching and can lead to weak d–d transitions .…”