Inorganic Phosphate and Arsenate within New Tetranuclear Copper and Zinc Complexes: Syntheses, Crystal Structures, Magnetic, Electrochemical, and Thermal Studies.

Three, PO /HPO and AsO -incorporated, new tetranuclear complexes of copper(II) and zinc(II) ions have been synthesized and fully characterized. In methanol-water, reactions of Hcpdp (Hcpdp = ,'-Bis[2-carboxybenzomethyl]-,'-Bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) with copper(II) chloride in the presence of either NaOH/NaHPO·2HO or KOH/NaHAsO·7HO lead to the isolation of the tetranuclear complexes Na[Cu(cpdp)(μ-PO)](OH)·14HO () and K[Cu(cpdp)(μ-AsO)](OH)·16/HO (), respectively. Similarly, the reaction of Hcpdp with zinc(II) chloride in the presence of NaOH/NaHPO·2HO yields a tetranuclear complex, Na(HO)[Zn(cpdp)(μ-HPO)]Cl·12/HO (). All complexes are characterized by single-crystal X-ray diffraction and other analytical techniques, such as Fourier transform infrared and UV-vis spectroscopy, thermogravimetric and electrochemical studies. The solid-state molecular framework of each complex contains two monocationic [M(cpdp)] (M = Cu, Zn) units, which are exclusively coordinated to either phosphate/hydrogen phosphate or arsenate groups in a unique mode. All three complexes exhibit a μ:η:η:η:η bridging mode of the PO /HPO /AsO groups, with each bridging among four metal ions. The thermal properties of all three complexes have been investigated by thermogravimetric analysis. Low-temperature magnetic studies of complexes and disclose moderate antiferromagnetic interactions mediated among the copper centers through alkoxide and phosphate/arsenate bridges. Electrochemical studies of complexes and in dimethylformamide using cyclic voltammetry reveal the presence of a fairly assessable one-electron metal-based irreversible reduction and one quasireversible oxidation couple.