Spectroscopic and electrochemical properties of [Mn(phen)(CO)3(imidazole)](SO3CF3) complexes

The Effects of the Substitution on the lmidazole Ligand on the Photochemical Properties of fac[Mn(CO)3(phen)(lmidazole)](SO3CF3) Complexes¶

“…For various [MnX(L‐L)(CO) 3 ] + type complexes, the lowest energy transitions were assigned to the Mn → (α‐diimine) π* orbital transitions (8–17). However, some π*‐character contribution of Mn → CO transition may be expected as well (22,23).…”

“…During the past decade there has been a considerable interest in the photophysics and photochemistry of Re(I) and Mn(I) carbonyl complexes that have low‐lying metal‐to‐ligand charge transfer (MLCT) excited states (1–17). For example, [M(CO) 3 (phen)Im], where M is Mn(I) or Re(I) metal transition, phen is 1,10‐ phenanthroline and Im is imidazole, has been studied (14–17). In the case of Re(I) complexes, the design of molecular architectures with imidazole has aroused interest in understanding bimolecular interactions with metal ions in biology and providing models for the active sites of metalloproteins (16,17).…”

“…In this context, ongoing studies deal with the preparation and thermal and photochemical evaluation of Mn(I) compounds, which may participate photochemically in efficient inter‐ and intramolecular energy‐ and electron‐transfer processes. For example, we have prepared several compounds of the type fac ‐[Mn(CO) 3 (phen)(Im‐R)], R = ‐H, ‐CH 3 , ‐C 6 H 5 , ‐Metro, Metro is 2‐methyl‐5‐nitroimidazole, in which the lowest lying energy transitions have MLCT character (14,15). The photoreactions resulting from MLCT excitation of fac ‐[Mn(CO) 3 (phen)(Im‐R)], R = ‐H, ‐CH 3 complexes were reported to lead to mer complexes.…”

“…The emission was observed to be sensitive to the nature of the environment, temperature and irradiation wavelength. In comparison with the rhenium complexes the manganese chemistry is of interest, primarily because of the wide range of oxidation states (20), reactivity of the complexes (8–15) and photochemical and photophysical properties (14,15).…”

“…In view of the observation that small changes in the nature of the “spectator” ligand can have a major effect on the properties of the complexes (14,15), a complete study of the photochemistry and photophysics of monometallic Mn(I) tricarbonyl complexes containing several ligands has been undertaken. In this article we report the results obtained for fac ‐[Mn(CO) 3 (phen)(Im‐R)](SO 3 CF 3 ) complexes using imidazole ligands substituted with ‐C 6 H 5 and ‐Metro to evaluate the effect of the electron‐donating or electron‐withdrawing nature of the imidazole and, consequently, control the relative positions of the ligand field (LF) and MLCT excited states, “tuning” the photophysical and photochemical properties of these complexes.…”