title: Photo- and solvatochromic properties of nitrobenzospiropyran in ionic liquids containing the [NTf2]- anion.
abstract: The photo-, thermo- and solvatochromic properties of 2,3-dihydro-1',3',3'-trimethyl-6-nitrospiro-[1-benzopyran-2,2'-1H-indole] (BSP-NO(2)) were studied in ILs containing the anion [NTf(2)](-) by UV-Vis absorption spectroscopy, ab initio molecular orbital theory and density functional theory (DFT) calculations. It was found that the kinetics and thermodynamics of the BSP-NO(2) <--> MC (merocyanine) equilibrium was sensitive to the nature of the cation. It was also observed that the imidazolium cation can form a through-space orbital interaction with the MC isomer, rather than a simple electrostatic interaction, thus preventing the MC conversion back to the BSP-NO(2) isomer. The BSP-NO(2) <--> MC equilibrium thus serves as a model system for studying modes of interaction of the cations in ionic liquids.
authors.affiliation: Adaptive Sensors Group, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Robert
authors.initials: R
authors.lastname: Byrne
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Fraser
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Izgorodina
authors.forename: Douglas R
authors.initials: DR
authors.lastname: MacFarlane
authors.forename: Maria
authors.initials: M
authors.lastname: Forsyth
authors.forename: Dermot
authors.initials: D
authors.lastname: Diamond