Abstract
A combined experimental study and density functional theory calculations of fac-[MnBr (CO)(3)L] complexes (L = 2-(2 '-pyridyl)benzimidazole ligand, furnished with either morpholine (L-morph) or phthalimido (L-phth) side-chain) were performed using different spectral and analytical tools. The synthesized complexes released carbon monoxide upon the exposure to LED source light at 468 nm. Illumination of fac-[MnBr (CO)(3)L] (10 mu M) in the myoglobin solution (Mb) produced about 25 mu M MbCO. The plateau of the CO release process is attained within 25 min. With the aid of time-dependent density functional theory calculations, the observed lowest energy absorption transition at similar to 400 nm has a ground-state composed of d (Mn)/pi (pyridyl) and excited-state of ligand pi*-orbitals forming MLCT/pi-pi*. Natural population analyses of fac-[MnBr (CO)(3)L] were carried out to get information about the strength of Mn-CO bonds, electronic arrangment and natural charge of manganese ion.