Related Experiment Video
Updated: Aug 16, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Evidence for static quenching of MLCT excited states by iodide
Christopher C Clark1, Andras Marton, Gerald J Meyer
1Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Abstract:
The metal-to-ligand charge-transfer (MLCT) excited states of Ru(deeb)(bpy)(2)(PF(6))(2) [where bpy is 2,2-bipyridine and deeb is 4,4'-(CO(2)CH(2)CH(3))(2)-2,2'-bipyridine] in acetonitrile or dichloromethane were found to be quenched by iodide at room temperature. The ionic strength dependence of the optical spectra gave evidence for ion pairing. Iodide is found to quench the photoluminescence (PL) intensity and influence the spectral distribution of the emitted light. A static component to the time-resolved PL quenching provided further evidence for ground-state adduct. Stern-Volmer analysis of the static component provided an estimate of the iodide-Ru(deeb)(bpy)(2)(2+) adduct equilibrium constant in dichloromethane, K(sv) = 40,000 M(-)(1). Transient absorption studies clearly demonstrate that an electron-transfer quenching mechanism is operative and that I(2)(-)(*) can be photoproduced in high yield, phi = 0.25. For Ru(bpy)(3)(PF(6))(2) in acetonitrile, similar behavior could be observed at iodide concentrations >100 times that required for dichloromethane.
Related Concept Videos
Precipitation of Ions
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
Alkyl Halides
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
E1 Reaction: Kinetics and Mechanism
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Mass Spectrometry: Alkyl Halide Fragmentation
Redox Titration: Iodimetry and Iodometry

