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

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-Re-5). Hybridization was achieved with the non-ionic surfactant C12H25(OCH2CH2)(4)OH in an acetonitrile solution, and in the hybrid (Ru-Re-5-Bp-PMO), the Ru-Re-5 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-Re-5 and then transferred to only one Ru unit, which emitted the light strongly.