Crystal structures of chlorido-[dihy-droxybis-(1-imino-eth-oxy)]arsanido-κ3 N, As, N']platinum(II) and of a polymorph of chlorido-[dihy-droxybis-(1-imino-prop-oxy)arsanido-κ3 N, As, N']platinum(II)

Acta Crystallogr E Crystallogr Commun. 2020 Jan 10;76(Pt 2):180-185. doi: 10.1107/S2056989019016463. eCollection 2020 Feb 1.

Abstract

Each central platinum(II) atom in the crystal structures of chlorido-[dihy-droxybis-(1-imino-eth-oxy)arsanido-κ3 N,As,N']platinum(II), [Pt(C4H10AsN2O4)Cl] (1), and of chlorido-[dihy-droxybis-(1-imino-prop-oxy)arsanido-κ3 N,As,N']platinum(II), [Pt(C6H14AsN2O4)Cl] (2), is coordinated by two nitro-gen donor atoms, a chlorido ligand and to arsenic, which, in turn, is coordinated by two oxygen donor ligands, two hydroxyl ligands and the platinum(II) atom. The square-planar and trigonal-bipyramidal coordination environments around platinum and arsenic, respectively, are significantly distorted with the largest outliers being 173.90 (13) and 106.98 (14)° for platinum and arsenic in (1), and 173.20 (14)° and 94.20 (9)° for (2), respectively. One intra-molecular and four classical inter-molecular hydrogen-bonding inter-actions are observed in the crystal structure of (1), which give rise to an infinite three-dimensional network. A similar situation (one intra-molecular and four classical inter-molecular hydrogen-bonding inter-actions) is observed in the crystal structure of (2). Various π-inter-actions are present in (1) between the platinum(II) atom and the centroid of one of the five-membered rings formed by Pt, As, C, N, O with a distance of 3.7225 (7) Å, and between the centroids of five-membered (Pt, As, C, N, O) rings of neighbouring mol-ecules with distances of 3.7456 (4) and 3.7960 (6) Å. Likewise, weak π-inter-actions are observed in (2) between the platinum(II) atom and the centroid of one of the five-membered rings formed by Pt, As, C, N, O with a distance of 3.8213 (2) Å, as well as between the Cl atom and the centroid of a symmetry-related five-membered ring with a distance of 3.8252 (12) Å. Differences between (2) and the reported polymorph [Miodragović et al. (2013 ▸). Angew. Chem. Int. Ed. 52, 10749-10752] are discussed.

Keywords: arsenoplatin; cisplatin; crystal structure; platinum.

Grants and funding

This work was funded by Universiteit van die Vrystaat grant . South African National Research Foundation grant .