Complexation of the antihypertensive drug oxprenolol with copper(II)

The complexation between copper(II) and the antihypertensive drug oxprenolol (HOxp) was studied both in methanol and slightly alkaline aqueous media at Cu:HOxp molar ratio from 1:1 to 1:10. Copper(LI) forms two types of complexes-a mononuclear violet one, CuOxp(2), with bidentately bound ligands and a green dimeric one, Cu(2)Oxp(2)Cl(2), in which the two Cu(II) centres are linked by the ligand through oxygen bridges. The crystal structure of the Cu(2)Oxp(2)Cl(2) complex consists of two crystallographically non-equivalent centrosymmetric copper dimers. Each copper atom is four-coordinated in a distorted square-planar environment. The Cu2O2 structural core is characterized by a Cul-Ol-Cul' angle of 104.15(13)degrees (Cu2-O2-Cu2' 104.30(13)degrees) and a relatively short Cul-Cul' separation of 3.026(1) Angstrom (Cu2-Cu2'-3.023(1) Angstrom). Magnetic susceptibility and EPR measurements indicate an antiferromagnetic coupling of the copper(II) centers. (C) 2001 Elsevier Science B.V. All rights reserved.