Synthesis and structural characterization of novel neutral fac-M(CO) 3(NSO) complexes (M = Re, 99mTc) with N-acetylcysteine derivatives as tridentate NSO ligands

Abstract

The reaction of [NEt 4] 2[Re(CO) 3Br 3] with equimolar amount of a tridentate NSO ligand in methanol leads to the formation of neutral tricarbonyl rhenium(I) complexes of the general formula Re(CO) 3(NSO), where the NSO ligand is o-C 5H 4N-CH 2CH 2-S-CH 2CH(NHCOCH 3)COOH (L 1H), complex 1 or o-C 5H 4N-CH 2CH 2-S-C(CH 3) 2CH(NHCOCH 3)COOH (L 2H), complex 2. Both complexes have been characterized by elemental analysis and spectroscopic methods, while complex 2 has also been characterized by X-rays analysis. At technetium-99m level, the corresponding fac-[ 99mTc(CO) 3(NSO)] complexes 3 and 4, were obtained in high yield by reacting ligands L 1H or L 2H with the fac-[ 99mTc(CO) 3(H 2O) 3] + precursor in water. Their structure was established by chromatographic comparison to the prototype rhenium complex using high-performance liquid chromatographic techniques.