A method of molecular design of self-assembling metal complexes has been established. The copper(II) complex with a quadridentate ligand [Cu(HL2)]ClO4 undergoes deprotonation of the imidazole proton under basic conditions to give an imidazolate-bridged polymeric compound [(CuL2)∞], where H2L2 = N-3-ethoxysalicylidene-N′-imidazol-4-ylmethylenecyclohexane-1,2-diamine. The latter compound crystallizes in the monoclinic space group P21/a with a = 15.515(5), b = 9.338(5), c = 12.660(2) Å, β = 95.33(2)°, and Z = 4, R = 0.078 for 1721 reflections. It has an infinite zigzag-chain structure and the variable-temperature magnetic data are well reproduced using the Ising model based on H = -2∑JijSiSj with a J value of -1.8 cm-1. The complex [Cu(HL3)Cl]ClO4 with a tridentate ligand gives an imidazolate-bridged tetranuclear complex [(CuL3)4][Clo4]4 on deprotonation at the imidazole nitrogen, where HL3 = N-imidazol-4-ylmethylene-N′,N′-dimethylpropane-1,3-diamine. The latter compound crystallizes in the triclinic space group P1 with a = 15.216(6), b = 15.592(5), c = 15.102(5) Å, α = 104.98(3)°, β = 108.44(3)°, γ = 61.12(2)°, Z = 2, and R = 0.096 for 6931 reflections. The structure consists of a cyclic tetranuclear molecule in which each imidazolate nitrogen atom co-ordinates axially to the copper(II) ion of the adjacent unit. Variable-temperature magnetic data are well reproduced using the Heisenberg model based on H = -2J(S1·S2 + S2·S3 + S3·S4 + S4·S1) with J = -60.0 cm-1.
|Number of pages||6|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - 1993|
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