Aromatic Chelator-Specific Lattice Architecture and Dimensionality in Binary and Ternary Cu(II)-Organophosphonate Materials

Abstract

Synthetic efforts linked to the design of defined lattice dimensionality and architecture materials in the binary/ternary systems of Cu(II) with butylene diamine tetra(methylene phosphonic acid) (H8BDTMP) and heterocyclic organic chelators (pyridine and 1,10-phenanthroline) led to the isolation of new copper organophosphonate compounds, namely, Na6[Cu2(BDTMP)(H2O)4]·[Cu2(BDTMP)(H2O)4]0.5·26H2O (1), [Cu2(H4BDTMP)(py)4]·2H2O (2), and [Cu2(H4BDTMP)(phen)2]n·6.6nH2O·1.5nMeOH (3). 1-3 are the first compounds isolated from the Cu(II)-BDTMP family of species. They were characterized by elemental analysis, spectroscopic techniques (FT-IR, UV-vis), magnetic susceptibility, TGA-DTG, cyclic voltammetry, and X-ray crystallography. The lattice in 1 reveals the presence of discrete dinuclear Cu(II) units bound to BDTMP(8-) and water molecules in a square pyramidal geometry. The molecular lattice of 2 reveals the presence of ternary dinuclear assemblies of Cu(II) ions bound to H4BDTMP(4-) and pyridine in a square pyramidal environment. The molecular lattice of 3 reveals the presence of dinuclear assemblies of Cu(II) ions bound to H4BDTMP(4-) and 1,10-phenanthroline in a square pyramidal environment, with the organophosphonate ligand serving as the connecting link to abutting dinuclear Cu(II) assemblies in a ternary polymeric system. The magnetic susceptibility data on 1, 2, and 3 suggest that compounds 1 and 3 exhibit a stronger antiferromagnetic behavior than 2, which is also confirmed from magnetization measurements. The physicochemical profiles of 1-3 (a) earmark the influence of the versatile H8BDTMP ligand as a metal ion binder on the chemical reactivity in binary and ternary systems of Cu(II) in aqueous and nonaqueous media and (b) denote the correlation of ligand hydrophilicity, aromaticity, denticity, charge, and H-bonding interactions with emerging defined Cu(II)-H8BDTMP structures of distinct lattice identity and spectroscopic-magnetic properties. Collectively, such structural and chemical factors formulate the interplay and contribution of binary and ternary interactions to lattice architecture and specified properties of new Cu(II)-organophosphonate materials with defined 2D-3D dimensionality.