256445-20-2Relevant articles and documents
Synthesis, magnetism, 1H NMR and redox activity of dicopper(II) complexes having a discrete {Cu2(μ-phenoxide)2}2+ unit supported by a non-macrocyclic ligand environment. Crystal structure of [Cu2(L)2(OCIO3)2] [HL = 4-methyl-2,6-bis(pyrazol-1-ylmethyl)-phenol]
Gupta, Rajeev,Mukherjee, Sumitra,Mukherjee, Rabindranath
, p. 4025 - 4030 (1999)
Reaction between 4-methyl-2,6-bis(pyrazol-l-ylmethyl)phenol (HL) or its 3,5-dimethylpyrazole derivative (HL′) and Cu(ClO4)2·6H2O afforded [CuII2(L/L′)2(OClO3) 2] 1 and 2. Complex 1 has been structurally characterized showing that each copper(II) centre is square pyramidal with two bridging phenoxide oxygens and two terminal pyrazole nitrogens in the equatorial plane and a perchlorate oxygen atom axially co-ordinated. Variable-temperature magnetic susceptibility measurements revealed that the dicopper(II) centres are strongly antiferromagnetically coupled [singlet-triplet energy separation, 2J (in cm-1): -1204 for 1 and -798 for 2]. The complexes exhibit 1H NMR spectra within δ 0-10 due to their S = 0 ground state. In MeCN solution they exhibit ligand field transitions in the range 14 300-16 600 cm-1 and phenolate-to-copper(II) charge-transfer transition at ≈22 700 cm-1. In MeCN solution each complex displays three consecutive irreversible responses (scan rate of 50 mV s-1) with Epc values (V vs. SCE) at -0.02, -0.54 and -0.86 (1) and 0.00, -0.42 and -0.80 (2). The first two responses are due to CuIICuI and the most cathodic response to CuI-Cu0 redox processes, respectively. The Royal Society of Chemistry 1999.
