Dinuclear CuIIMII (M = Co, Ni, Cu or Zn) and Cu IICuI complexes of a phenol-based dinucleating macrocycle with dissimilar N2O2 and N2O2S sites

Shin Ichiro Ohtsuka, Masahito Kodera, Ken Ichiro Motoda, Masaaki Ohba, Hisashi Okawa

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Abstract

A dinucleating macrocycle H2L with two 2,6-bis(iminomethyl)-4- methylphenolate entities combined through two lateral chains, CH 2CH2 and CH2CH2SCH 2CH2, at the imino nitrogens has been obtained as a mononuclear copper(II) complex [Cu(H2L)][ClO4] 2. It reacted with a second metal ion under alkaline conditions to form dinuclear complexes [CuIIMIIL(NCS) 2]·H2O (M = Co, Ni or Zn), [CuIICu IIL][ClO4]2 and [CuIICu IL]ClO4. The crystal structure of the dimethylformamide adduct, [CuZnL(NCS)2]·dmf, reveals the discrete CuZn dinuclear structure bridged by the two phenolic oxygens of (L)2-. The Cu II resides at the site with the CH2CH2 lateral chain and assumes a square-pyramidal geometry together with an isothiocyanato nitrogen at the apex. The ZnII is at the site with the CH 2CH2SCH2CH2 chain and assumes a similar square-pyramidal geometry with an isothiocyanato nitrogen at the apex. The sulfur on the lateral chain is not co-ordinated but disposed to the Zn II with the Zn ⋯ S separation of 3.48 Å. An antiferromagnetic spin exchange operates in the CuIIMII (M = Co, Ni or Cu) complexes (J = -32 cm-1 for M = Co, -90 cm -1 for M = Ni and -440 cm-1 for M = Cu based on H = -2JS1S2). In cyclic voltammograms of [Cu IICuIIL][ClO4]2 and [Cu IICuIL]ClO4 the copper ion at the site with the CH2CH2SCH2CH2 lateral chain shows a reversible CuII-CuI redox couple at ≈ +0.08 V (vs. saturated calomel electrode).

Original languageEnglish
Pages (from-to)2599-2604
Number of pages6
JournalJournal of the Chemical Society, Dalton Transactions
Issue number16
DOIs
Publication statusPublished - Dec 1 1995

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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