6533b821fe1ef96bd127c0a3

RESEARCH PRODUCT

Structure and properties of a novel staircase-like decanuclear [CuII10] cluster supported by carbonate and carboxylate bridges

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This article describes a novel staircase-like decanuclear copper(II) cluster [CuII10(cpdp)4(CO3)4(CH3OH)2]·3.33CH3OH·7.83H2O (1) (H3cpdp = N,N′-bis[2-carboxybenzomethyl]-N,N′-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) composed of a pair of [CuII5] pentamers. In methanol, the reaction of H3cpdp with Cu(NO3)2·3H2O in the presence of K2CO3 leads to the isolation of complex 1. This complex has been characterized by various analytical techniques including single crystal X-ray crystallography. Structural analysis reveals that the two [CuII5] pentameric units are bridged together exclusively by two μ2:η2:η1 carbonate groups. Complex 1 shows a rare μ3:η2:η1:η1 bridging coordination mode of four benzoate groups of cpdp3− ligands with each bridging among three copper(II) ions. Complex 1 also represents the first example of a carbonate-coordinated decanuclear copper(II) cluster with any class of bridging or non-bridging ligand. Thermal, magnetic, EPR and electrochemical properties of this complex have been discussed. Variable temperature magnetic measurement discloses the antiferromagnetic interactions among the copper(II) ions. Electrochemical investigation of 1 in methanol solution using cyclic voltammetry reveals the presence of one metal-based quasi-reversible reduction at 870 mV (ΔEp = 190 mV).