Conformational and structural diversity of iridium di­methyl sulfoxide complexes

BENJAMIN MARC RIDGWAY; ANA FOI; RODRIGO S. CORRÊA; DAMIAN E. BIKIEL; JAVIER ELLENA; FABIO DOCTOROVICH; FLORENCIA DI SALVO

ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0108-7681

Transition metal complexes containing DMSO are important precursors in catalysis and metallodrugs. Understanding the solid-state supramolecular structure is crucial to predict material properties and biological activity. Several crystalline phases of DMSO-coordinated iridium anions with different cations, potassium (1a) and n-butylammonium (1b), were obtained and their structures determined by X-ray crystallography. Compound 1a is present in two solvatomorphic forms: α and β; the β form contains disordered solvent water. In addition, the structures exhibit different rotamers of the trans-[IrCl4(DMSO)2]- anion with the trans-DMSO ligands being oriented in anti and gauche conformations. Considering these various conformers, we discuss the effect of the crystallised solvent and intermolecular interactions on the conformational preferences of the anion. In addition, we use density functional theory calculations to investigate the energies of the anions in the different conformations. We found that hydrogen bonds between water and the DMSO complex stabilise the gauche conformation, which is the least stable form, of the trans-DMSO complex. Consequently, by controlling the number of hydrogen-bond donors and acceptors and the amount of water, it may be possible to obtain different solvatomorphs of clinically significant metallodrugs.