Abstract Benzimidazolic coordination compounds with metals or lanthanides have attracted the interest of scientists due to their electronic properties, such as luminescence, semiconducting behaviour and catalytic. They find use, for example, in optoelectronics. This study investigates the photophysical, electronic, and electrochemical properties of benzimidazole-based coordination complexes formed from the reaction of a Schiff base with Ru 3+ or La 3+ ions. We present the synthesis of a Schiff base and its benzimidazole complexes via coordination with RuCl₃∙xH₂O or La(NO₃)₃∙5H₂O and their characterisation using NMR, FTIR, UV–Vis, EPR spectroscopies, electrochemical analysis, SEM–EDS and quantum mechanical calculations. The results show that coordination with Ru 3+ and La 3+ stabilises organic radicals. Optical band gap analysis indicates metal coordination slightly lowers the energy gap, confirming their semiconductor behaviour. UV–Vis and emission spectroscopy revealed Förster Resonance Energy Transfer (FRET), metal-to-ligand (M→L) and ligand-to-metal (L→M) energy transfer phenomena. Electrochemical studies indicate that the lanthanum complex exhibits oxidative photocatalysis due to L→M energy transfer, while the ruthenium complex exhibits reductive photocatalysis due to M→L energy transfer. The findings highlight the potential of these benzimidazole-based coordination complexes in applications ranging from electronics to catalysis. Graphical Abstract
Contreras-Cadena et al. (Thu,) studied this question.