Copper(II) complexes of the beta-blocker pindolol: properties, structure, biological activity

The complex formation between copper(II) and the antihypertensive drug pindolol (HPin) was studied both in aqueous and methanolic media. Two complexes are formed at different metal-to-ligand molar ratios. The mononuclear complex Cu(Pin)2(HPin)2 contains two ligands in an anionic bidentate form and two--in a neutral form bound monodentately. The second complex Cu2Pin2Cl2 is dinuclear and its structure was determined by X-ray diffraction. The compound crystallizes in the monoclinic group C2/c with cell components a = 14.4998(13)A, b = 18.511(2)A, c = 14.2982(13)A, alpha = 90 degrees, beta = 109.556(2) degrees, gamma = 90 degrees and Z = 12 at 293K. A pharmacological study on the influence of pindolol and its mononuclear complex on the heart rate of rats was performed. The complex is more active and has a longer effect in comparison with the pure non-coordinated pindolol in equitoxic doses.