Cucurbit[5]uril–metal complex-induced room-temperature phosphorescence of α-naphthol and β-naphthol

摘要: Similar to the larger members of cucurbituril family, such as cucurbit[8]uril (Q[8]), smallest member, cucurbit[5]uril (Q[5]), can also induce room-temperature phosphorescence (RTP) α-naphthol (1) and β-naphthol (2). The relationship between RTP intensity 1 2 concentration Q[5] or Q[8] suggests that mechanism underlying complex-induced is different from Q[8]-induced for these luminophores. crystal structures 1–Q[5]–KI, 2–Q[5]–KI, 1–Q[5]–TlNO3, 2–Q[5]–TlNO3 systems show in each case respective metal ions, K+ Tl+, form infinite ⋯Q[5]–M+–Q[5]–M+⋯ chains surround Although tube- wall-like are likely destroyed solution, key interaction convex-shaped outer walls plane aromatic naphthols, via π⋯π stacking C–H⋯π interactions, postulated be essentially maintained leading a microenvironment holds luminophore heavy atom perturber together; model supported by observed above naphthols. With respect this, high Q[5]/luminophore was employed an endeavour promote formation interactions similar those 1– 2–Q[5]–K+ –Tl+ systems. In keeping with proposed model, system quenched when replaced alkyl-substituted derivatives, decamethylQ[5] pentacyclohexanoQ[5]. This agreement substituent groups on surface metal-bond obstructing naphthol molecule accessing convex glycouril backbone Q[5].