Aromatic
Chelator-Specific Lattice Architecture and Dimensionality in Binary
and Ternary Cu(II)-Organophosphonate Materials
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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) (H<sub>8</sub>BDTMP)
and heterocyclic organic chelators (pyridine and 1,10-phenanthroline)
led to the isolation of new copper organophosphonate compounds, namely,
Na<sub>6</sub>[Cu<sub>2</sub>(BDTMP)(H<sub>2</sub>O)<sub>4</sub>]·[Cu<sub>2</sub>(BDTMP)(H<sub>2</sub>O)<sub>4</sub>]<sub>0.5</sub>·26H<sub>2</sub>O (<b>1</b>), [Cu<sub>2</sub>(H<sub>4</sub>BDTMP)(py)<sub>4</sub>]·2H<sub>2</sub>O (<b>2</b>), and [Cu<sub>2</sub>(H<sub>4</sub>BDTMP)(phen)<sub>2</sub>]<sub><i>n</i></sub>·6.6<i>n</i>H<sub>2</sub>O·1.5<i>n</i>MeOH (<b>3</b>). <b>1</b>–<b>3</b> 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 <b>1</b> reveals the
presence of discrete dinuclear Cu(II) units bound to BDTMP<sup>8–</sup> and water molecules in a square pyramidal geometry. The molecular
lattice of <b>2</b> reveals the presence of ternary dinuclear
assemblies of Cu(II) ions bound to H<sub>4</sub>BDTMP<sup>4–</sup> and pyridine in a square pyramidal environment. The molecular lattice
of <b>3</b> reveals the presence of dinuclear assemblies of
Cu(II) ions bound to H<sub>4</sub>BDTMP<sup>4–</sup> 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 <b>1</b>, <b>2</b>, and <b>3</b> suggest that compounds <b>1</b> and <b>3</b> exhibit a stronger antiferromagnetic
behavior than <b>2</b>, which is also confirmed from magnetization
measurements. The physicochemical profiles of <b>1</b>–<b>3</b> (a) earmark the influence of the versatile H<sub>8</sub>BDTMP 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)–H<sub>8</sub>BDTMP 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
