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

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 BDTMP8– 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 H4BDTMP4– and pyridine in a square pyramidal environment. The molecular lattice
of 3 reveals the presence of dinuclear assemblies of
Cu­(II) ions bound to H4BDTMP4– 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.