Investigation of metal, redox and photochemical properties of newly designed ferrocenyl urea benzimidazole sensors by DFT method

In this study, it is aimed to investigate computationally electronic and photochemical properties of newly designed molecular sensors which is ferrocene-benzimidazole-based, sensitive to metal ions (Ca2+, Mg2+ ,Zn2+, Hg2+, Pb2+, Ni2+, Co2+, Cu2+), expected to exhibit redox and photochemical properties. The designed sensor consists of a binding unit containing a urea bridge connected to the ferrocene unit and a benzimidazole which gives a fluorescence signal attached thereto. For the molecular modeling, the Lanl2dz base set of the hybrid approach of the DFT method B3LYP (Rives and Jorgensen, 2008) was used. All calculations were done with RHF method (spin multiplication = 1) in two separate phases, gas and water phase. When the photochemical and electrochemical properties of the designed sensor are theoretically analyzed, the potential values of the sensor for reduction with metal ions range from 1,078 V to 0,968 V. In the water phase, the most volatile gibbs free energy belongs to the Ni-FcUB and Co-FcUB complexes (-122.19 kcal / mol and -99.83 kcal / mol, respectively). UV-visible region spectrums in the water phase give to blue-shift in presence of Ca2+, Mg2+, Hg2+, Zn2+ ions, but red-shift occurs in presence of Co2+, Cu2+, Ni2+, Pb2+ ions. In the same phase, the Co-FcUB sensor was found to give a maximum absorption wavelength at 780 nm.