Efficient light harvesting via sequential two-step energy accumulation using a Ru–Re5 multinuclear complex incorporated into periodic mesoporous organosilica

Abstract

An efficient artificial light harvesting (LH) system was developed via sequential two-step energy accumulation. A periodic mesoporous organosilica with bridging biphenyl groups in the framework (Bp–PMO) was used as an LH antenna. The center of a linear-shaped Re(I) pentanuclear complex was connected to a Ru(II) trisdiimine complex through a covalent bond, these served as the first and second energy acceptors, respectively, (Ru–Re₅). Hybridization was achieved with the non-ionic surfactant C₁₂H₂₅(OCH₂CH₂)₄OH in an acetonitrile solution, and in the hybrid (Ru–Re₅–Bp–PMO), the Ru–Re₅ molecules were adsorbed in an orderly fashion in the mesopores of the Bp–PMO. Photons absorbed by 437 ± 43 of the Bp units were first accumulated in the five Re units in Ru–Re₅ and then transferred to only one Ru unit, which emitted the light strongly.