title: Restriction of molecular twisting on a gold nanoparticle surface.
abstract: To understand the photophysical properties of intramolecular charge transfer (ICT) and twisted intramolecular charge transfer (TICT) states on a gold nanoparticle (Au NP) surface, we have designed and synthesized a new coumarin molecule (C3) that exists both as ICT and TICT states in its excited state in a polar environment. On a Au NP surface, an excited C3 molecule only exists as an ICT state owing to restricted molecular rotation of a diethylamino group; as a result, no conversion from the ICT to TICT state was observed. Selection of the preferential state of a molecule with dual emitting states can be helpful for selected biological applications.
authors.affiliation: Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India).
authors.forename: Tushar
authors.initials: T
authors.lastname: Debnath
authors.forename: Jayanta
authors.initials: J
authors.lastname: Dana
authors.forename: Partha
authors.initials: P
authors.lastname: Maity
authors.forename: Hyacintha
authors.initials: H
authors.lastname: Lobo
authors.forename: Ganapati S
authors.initials: GS
authors.lastname: Shankarling
authors.forename: Hirendra N
authors.initials: HN
authors.lastname: Ghosh
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D049408:Luminescent Agents / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003374:Coumarins; D049408:Luminescent Agents; D006046:Gold; C030123:coumarin
keywords: ICT and TICT states; coumarin dye; dual emission; gold nanoparticles; molecular rotation