The unprecedented preparation of dinuclear zinc(ii) complexes from 4-halido-2-[(3-cyclohexylaminopropylimino)methyl]phenol

Abstract

Three new centrosymmetric trinuclear nickel(II) and manganese(II) complexes, Ni[Ni(CH₃COO)(CPA)]₂ (1), Ni[Ni(CH₃COO)(BPA)]₂ (2), Mn[Mn(CH₃COO)(BPA)]₂ (3), where H₂CPA = N,N′-bis(5-chlorosalicylidene)-1,3-propanediamine, H₂BPA = N,N′-bis(5-bromosalicylidene)-1,3-propanediamine, and two new centrosymmetric dinuclear zinc(II) complexes, [Zn₂(CMP)₂] (4) and [Zn₂(BMP)₂] (5), where H₂CMP = 4-chloro-2-{[3-(5-chloro-2-hydroxybenzyl)aminopropylimino]methyl}phenol, and H₂BMP = 4-bromo-2-{[3-(5-bromo-2-hydroxybenzyl)aminopropylimino]methyl}phenol, have been prepared from the Schiff bases derived from 5-halido-substituted salicylaldehydes with N-hexylpropane-1,3-diamine under solvothermal conditions. The complexes have been characterised by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction studies. The complexes 1, 2, and 3 crystallise in the monoclinic space groupP2₁/c with cell dimensions a = 9.347(1), b = 11.507(2), c = 18.539(2) Å, β = 93.774(2)°, Z = 2 (for 1), a = 9.111(4), b = 12.089(6), c = 18.724(8) Å, β = 92.117(7)°, Z = 2 (for 2), and a = 11.328(2), b = 22.468(5), c = 8.270(2) Å, β = 93.74(3)°, Z = 2 (for 3), while complexes 4 and 5 crystallise in the triclinic space group P, with cell dimensions a = 7.483(1), b = 9.990(2), c = 12.155(2) Å, α = 75.27(3), β = 85.00(3), γ = 73.82(3)°, Z = 1 (for 4), and a = 7.008(1), b = 10.081(2), c = 13.095(3) Å, α = 100.62(3), β = 95.51(3), γ = 104.03(3)°, Z = 1 (for 5). It is interesting that the mono-Schiff bases 4-chloro-2-[(3-cyclohexylaminopropylimino)methyl]phenol (HCCP) and 4-bromo-2-[(3-cyclohexylaminopropylimino)methyl]phenol (HBCP) used to prepare the nickel(II) and manganese(II) complexes were transferred to bis-Schiff bases H₂CPA and H₂BPA in the complexes 1, 2, and 3, while the mono-Schiff bases HCCP and HBCP used to prepare the zinc(II) complexes were transferred to novel ligands H₂CMP and H₂BMP, bearing the unexpected, newly formed carbon–nitrogen single bond.