Interaction of the Large Host Q[10] with Metal Polypyridyl Complexes: Binding Modes and Effects on Luminescence

Abstract

Aqueous solution state host−guest systems have been studied, comprising the large host cucurbit[10]uril with luminescent cationic tris(polypyridyl) (PP) metal complexes [Ru(PP) 3 ] 2+ and [Ir(PP) 3 ] 3+ . All complexes bind strongly with the host, with the overall complex charge and size having a minor effect on affinity but influencing the association dynamics and contribution from higher-order (1:2) host−guest species. The 1:2 species contributes more significantly to the binding equilibrium in the case of [Ru(phen) 3 ] 2+ . The effect of the host upon emission is highly variable and depends on the electronic structure of the guest. The metal-to-ligand charge transfer (MLCT) emission of [Ru(PP) 3 ] 2+ is strongly quenched, in contrast to the large enhancements seen previously for MLCT emission of iridium cyclometalated complexes, while the ligand-centered emission of [Ir(PP) 3 ] 3+ is little affected. The mechanisms of quenching and enhancement are discussed, together with the implications for the design of larger supramolecular assemblies based on these archetypal emitters.

Triboluminescence Phenomenon Based on the Metal Complex Compounds—A Short Review

“…Kalyanasundaram K. reported the quantum yield of the described complex in an aqueous solution as 0.044 [38]. [24]. Glyus L. Sharipov and Adis A. Tukhbatullin described fundamental spectroscopic properties of the obtained complex.…”

“…Full 1 H NMR spectrum (400 MHz) of Ru(II)-metal complex in D2O was obtained at room temperature. The clear signals coming from the 2,2′-bipyridine system were found (Figure 10) [24]. The described complex contains the Mn +II ion surrounded by two Br − ions and two triphenylphosphine oxide, which are bonded with the metal atom by oxygen atoms (Figure 12).…”

“…Figure 9b shows MS spectra with a lo level of collisional activation; the peak at m/z 285 corresponds to the Ru(bpy)3 2+ ion [3 Full 1 H NMR spectrum (400 MHz) of Ru(II)-metal complex in D2O was obtained at roo temperature. The clear signals coming from the 2,2′-bipyridine system were found (Figu 10) [24].…”

“…In some publications, authors used the purchased [Ru(bpy) 3 ]Cl 2 complex [ 24 , 25 ], although it can be synthesized in several different ways. Sumana Bhar and Rajakumar Ananthakrishnan prepared the Ru(II)-metal complex with 70% yield by following the method in [ 8 ].…”

“…Photoluminescent properties are observed in the [Ru(bpy) 3 ]Cl 2 • • • 6H 2 O complex because of the presence of the [Ru(bpy) 3 ] 2+ cations[24]. Glyus L. Sharipov and Adis A. Tukhbatullin described fundamental spectroscopic properties of the obtained complex.…”