Synthesis, X-ray structures, and cytotoxicity of rhenium(I) carbonyl 2-(dimethylamino)ethoxide complexes

Abstract

The complexes [Re(η2-Me2NCH2CH2O) (CO)3(μ-OH)Re(η2-Me2 NCH2CH2OH)(CO)3] (1) and [Re3(μ3-OH)(μ-OH)2(μ-OCH2 CH2NMe2H)(CO)9] (2) have been synthesised and characterised by single-crystal X-ray diffraction analysis. Complex 1 exists as hydrogen-bonded dimers in the solid state and in solution. Proton NMR, 1H-1H COSY and NOESY spectroscopic studies showed that the structure of 1 is static in solution, and that only one of the many possible geometric isomers of 1 exists. The hydrogen atom on the ammonio nitrogen of 2 is involved in intramolecular N-H⋯O hydrogen-bonding with a bridging OH group. Complexes 1 and 2 were shown to be potent in suspended tumour cell lines in suppressing growth but were more selective in inhibiting the growth of cultures from solid tumours. The compounds [NBun4][ReO4] and [NEt4]2[ReBr3(CO)3] were also very active against the suspended cell lines and selective against solid tumours. All the compounds tested are inactive against normal cells. © 2002 Elsevier Science Ltd. All rights reserved.