Further Studies of Co-III(TIM) Mono-Alkynyl and Bis-Alkynyl Complexes

A new series of mono- and bis-alkynyl Co-III(TIM) complexes (TIM=2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) is reported herein. The trans-[Co(TIM)(C2R)Cl](+) complexes were prepared from the reaction between trans-[Co(TIM)Cl-2]PF6 and HC2R (R=tri(isopropyl)silyl or TIPS (1), -C6H4-4-Bu-t (2), -C6H4-4-NO2 (3 a), and N-mesityl-1,8-naphthalimide or NAP(Mes) (4 a)) in the presence of Et3N. The intermediate complexes of the type trans-[Co(TIM)(C2R)(NCMe)](PF6)(OTf), 3 b and 4 b, were obtained by treating 3 a and 4 a, respectively, with AgOTf in CH3CN. Furthermore, bis-alkynyl trans-[Co(TIM)(C2R)(2)]PF6 complexes, 3 c and 4 c, were generated following a second dehydrohalogenation reaction between 3 b and 4 b, respectively, and the appropriate HC2R in the presence of Et3N. These new complexes have been characterized using X-ray diffraction (2, 3 a, 4 a, and 4 c), IR, H-1 NMR, UV/Vis spectroscopy, fluorescent spectroscopy (4 c), and cyclic voltammetry.