SOME NEW CATIONIC DICARBONYL AND TRICARBONYL COMPLEXES OF TECHNETIUM(I)

Some new low-valent, cationic complexes of technetium-99 have been pre pared. Oxidation of Tc2(CO)10 (1) with NOPF6 in acetonitrile gave [Tc( CH3CN)(CO)5]PF6 (2) quantitatively. This complex constitutes a useful precursor for cationic carbonyl complexes, as exemplified by a variety of reactions with bi- and tridentate ligands from which air-stable, w ater-soluble complexes of type [LTc(CO)3]+ (L = 1,4,7-triazacyclononan e, 1,4,7-trimethyl-1,4,7-triazacyclononane and 1,4,7-trithiacyclononan e) have been isolated and characterized. A series of mixed complexes o f technetium(I) of general formula {Tc(N,N)[P(OR)3]2(CO)2}PF6 (N,N = 2 ,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine and R = methyl, isopropy l) has also been prepared.