New platinum(II) complexes with benzo-thia-zole ligands

José A Carmona-Negrón; Mayra E Cádiz; Curtis E Moore; Arnold L Rheingold; Enrique Meléndez

doi:10.1107/S2056989016002826

New platinum(II) complexes with benzo-thia-zole ligands

Acta Crystallogr E Crystallogr Commun. 2016 Feb 24;72(Pt 3):412-6. doi: 10.1107/S2056989016002826. eCollection 2016 Mar 1.

Authors

José A Carmona-Negrón¹, Mayra E Cádiz¹, Curtis E Moore², Arnold L Rheingold², Enrique Meléndez¹

Affiliations

¹ University of Puerto Rico, Department of Chemistry, PO Box 9019, Mayaguez, PR 00681, Puerto Rico.
² University of California-San Diego, Department of Chemistry, Urey Hall 5128, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA.

Abstract

Four new platinum(II) complexes, namely tetra-ethyl-ammonium tri-bromido-(2-methyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C8H7NS)] (1), tetra-ethyl-ammonium tri-bromido-(6-meth-oxy-2-methyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C9H9NOS)] (2), tetra-ethyl-ammonium tri-bromido-(2,5,6-trimethyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C10H11NS)] (3), and tetra-ethyl-ammonium tri-bromido-(2-methyl-5-nitro-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C8H6N2O2S)] (4), have been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. These species are precursors of compounds with potential application in cancer chemotherapy. All four platinum(II) complexes adopt the expected square-planar coordination geometry, and the benzo-thia-zole ligand is engaged in bonding to the metal atom through the imine N atom (Pt-N). The Pt-N bond lengths are normal: 2.035 (5), 2.025 (4), 2.027 (5) and 2.041 (4) Å for complexes 1, 2, 3 and 4, respectively. The benzo-thia-zole ligands are positioned out of the square plane, with dihedral angles ranging from 76.4 (4) to 88.1 (4)°. The NEt4 cation in 3 is disordered with 0.57/0.43 occupancies.

Keywords: anticancer; benzothiazole; cisplatin; crystal structure; platinum(II).