A host-induced intramolecular charge-transfer complex and light-driven radical cation formation of a molecular triad with cucurbit[8]uril

摘要

The host-guest chemistry of systems containing a molecular triad Ru(bpy)(3)-MV2+-naphthol complex (denoted as Ru2+-MV2+-Np, 1) and cucurbit[8]uril (CB[8]) is investigated by NMR, EST-MS, UV-vis, and electrochemistry. The Ru2+-MV2+-Np guest and CB [8] host can form a stable 1:1 inclusion complex, in which the naphthalene residue is back-folded and inserted together with the viologen residue into the cavity of CB[8]. The selective binding of Ru2+-MV2+-Np guest with beta-CD and CB[8] host is also investigated. We find that CB[8] binds the Ru2+-MV2+-Np guest stronger than beta-CD. Upon light irradiation, a MV+center dot radical cation stabilized in the cavity of CB[8] accompanied by the naphthalene residue has been observed. This novel system may open a new way for design and synthesis of photoactive molecular devices.