Structural diversity in copper(I) iodide complexes with 6-thioxopiperidin-2-one, piperidine-2,6-dithione and isoindoline-1,3-dithione ligands

Abstract

Copper(I) iodide complexes are well known for displaying a diverse array of structural features even when only small changes in ligand design are made. This structural diversity is well displayed by five copper(I) iodide compounds reported here with closely related piperidine-2,6-dithione (SNS), isoindoline-1,3-dithione (SNS6), and 6-thioxopiperidin-2-one (SNO) ligands: di-μ-iodido-bis[(acetonitrile-κN)(6-sulfanylidenepiperidin-2-one-κS)copper(I)], [Cu2I2(CH3CN)2(C5H7NOS)2] (I), bis(acetonitrile-κN)tetra-μ3-iodido-bis(6-sulfanylidenepiperidin-2-one-κS)-tetrahedro-tetracopper(I), [Cu4I4(CH3CN)4(C5H7NOS)4] (II), catena-poly[[(μ-6-sulfanylidenepiperidin-2-one-κ2O:S)copper(I)]-μ3-iodido], [CuI(C5H7NOS)]n (III), poly[[(piperidine-2,6-dithione-κS)copper(I)]-μ3-iodido], [CuI(C5H7NS2)]n (IV), and poly[[(μ-isoindoline-1,3-dithione-κ2S:S)copper(I)]-μ3-iodido], [CuI(C8H5NS2)]n (V). Compounds I and II crystallize as discrete dimeric and tetrameric complexes, whereas III, IV, and V crystallize as polymeric two-dimensional sheets. To the best of our knowledge, compound III is the first instance of an extended hexagonal [Cu3I3] structure that is not supported by bridging ligands. Structures I, II, and IV display weak to moderately strong Cu...Cu cuprophilic interactions [Cu...Cu internuclear distances range between 2.5803 (10) and 2.8485 (14) Å]. All structures except III display weak hydrogen-bonding interactions between the N—H of the ligand and the μ2 and μ3-I− atoms. Structure III contains classical N–H...O interactions between the SNO ligands that connect the molecules in a three-dimensional framework. Complex V features π–π stacking interactions between the aryl rings of the SNS6 ligands within the same polymeric sheet. In structure IV, there were three partially occupied solvent molecules of dichloromethane and one partially occupied molecule of acetonitrile present in the asymmetric unit. The SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18] was used to correct the diffraction data for diffuse scattering effects and to identify the solvent molecules. The given chemical formula and other crystal data do not take into account the solvent molecules.

Keywords

• crystal structure
• copper(i) iodide
• coordination complexes