Interactions of metal ions with a 2,4-diaminopyrimidine derivative (trimethoprim) - Antibacterial studies

The interaction of copper (II), zinc(II) and cadmium(II) with Trimethoprim (2,4-diamino-5-(3',4',5'-trimethoxybenzyl) pyrimidine) has been studied. Th e crystal structures of [Zn(Trim)(2)Cl-2] (2) and [Cd(Trim)Cl-2(CH3OH)](n) (4) are reported. Compound (2) exhibits a distorted tetrahedral environment around the metal center and crystallizes in the triclinic space group P (1 ) over bar with a=10.2397(6), b=10.4500(6), c=16.3336(16) Angstrom, alpha = 96.141(8), beta =106.085(5), gamma =96.551(5)degrees and Z=2. In complex (4 ), the Cd(II) centers are bridged sequentially by two chlorine ions to form infinite chains and present a six-coordinated environment; the compound cr ystallizes in the monoclinic P2(1)/C space group with a=13.958(5), b=7.532( 2), c=18.390(2) Angstrom, alpha =90, beta =97.32(5), gamma =90 degrees and Z=4. In both structures the Trimethoprim acts as a monodentate ligand throu gh the pyrimidinic nitrogen N(1) atom. The characterization of the Cu(Trim) (2)(CH3O)(ClO4) complex through EPR and magnetic measurements suggests a bi nuclear or polinuclear nature, with bridging methoxo groups. The complexes were screened for their activity against several bacteria, showing activity similar to that of trimethoprim. (C) 2000 Elsevier Science S.A. All rights reserved.