Imidazolate-bridged Copper(II) Complexes with Infinite Zigzag-chain and Tetranuclear Structures formed by Deprotonation and Self-assembly

Article abstract of DOI:10.1039/DT9930002157

A method of molecular design of self-assembling metal complexes has been established.The copper(II) complex with a quadridentate ligand 2)>ClO4 undergoes deprotonation of the imidazole proton under basic conditions to give an imidazolate-bridged polymeric compound <(CuL²)infinite>, 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) Angstroem, β = 95.33(2) deg, 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 = -2ΣJ_ijS_iS_j with a J value of -1.8 cm^-1.The complex 3)Cl>ClO4 with a tridentate ligand gives an imidazolate-bridged tetranuclear complex <(CuL³)4>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 P<*> with a = 15.216(6), b = 15.592(5), c = 15.102(5) Angstroem, α = 104.98(3) deg, β = 108.44(3) deg, γ = 61.12(2) deg, 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.

Full text of DOI:10.1039/DT9930002157

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