Amino versus imino-transition metallic complexes in functionalized mesoporous silica: a lone pair degenerated into a singlet electron system

Imine terminated mesoporous silica nanoparticles (IMSNP) appear to be an effective mesoporous media with potential for multifarious applications such as catalytic support, effluent treatment, and sensors. With this goal, several transition metal (TM = Fe3+, Co2+, Ni2+, Cu2+) ions have been complexed with IMSNP and investigated. In this report, insights generated using microscopic probes (PL, ESR) reveal the inter-conversion of a covalent lone pair of electrons in the amine-functionalised mesoporous system (AMSNP), manifesting into a singlet electron state in the imine functionalised mesoporous system (IMSNP).