Synthesis and complexation of nickel(II) and copper(II) by pendant-arm alcohol derivatives of [9]aneNS2 (7-aza-1,4-dithiacyclononane)

Abstract

A simplified procedure for the preparation of [9]aneNS₂ (7-aza-1,4-dithiacyclononane) is described. The structure of the complex [Cu([9]aneNS₂)₂]²⁺ confirms that the Cu(II) centre is in a distorted octahedral environment, Cu–S(1) 2.5469(14), Cu–S(4) 2.5386(13), Cu–N(7) 2.016(4) Å. Reaction of [9]aneNS₂ with isobutylene oxide or 2,2-diphenyloxirane gives the alcohol derivatives, HL¹ and HL², respectively. The 1∶1 metal∶ligand complex [Cu₂(L¹)₂]²⁺ was found to be binuclear with the alcohol functions deprotonated to form alkoxide bridges between two Cu(II) centres, Cu–N(1) 2.042(4), Cu–S(4) 2.452(2), Cu–S(7) 2.430(2), Cu–O(14) 1.927(4), Cu–O(14′) 1.922(4), Cu–Cu′ 3.0063(9) Å, Cu–O–Cu′ 102.7(2)°. Magnetochemical data for this complex confirm antiferromagnetic coupling between the two Cu(II) centres with 2J = –417 ± 2 cm^–1. With Ni(II) the complex [Ni(HL¹)(CH₃CO₂)]⁺ can be isolated, the structure of which shows it to be a monomer with the ligand HL¹ acting as a tetradentate ligand to the metal centre, Ni–N(1) 2.064(3), Ni–S(4) 2.3658(12), Ni–S(7) 2.3875(13), Ni–O(14) 2.061(3) Å. A chelating acetate ligand completes the distorted octahedral geometry, Ni–O(16) 2.098(3), Ni–O(17) 2.102(3) Å.