title: Photoinduced electron transfer interaction of anthraquinones with aniline quenchers: Influence of methyl substitution in aniline donors.
abstract: Photoinduced electron transfer between triplet state of 9,10-anthraquinone (AQ) and its two derivatives: 2-chloro-9,10-anthraquinone (CAQ) and sodium anthraquinone-2-sulfonate (AQS) and ground state aniline (AN) and its dimethyl substitutions: 2,3-dimethylaniline (2,3-DMA), 2,6-dimethylaniline (2,6-DMA), 3,5-dimethylaniline (3,5-DMA) and N,N-dimethylaniline (N,N-DMA) is studied using nanosecond laser flash photolysis at room temperature. Detection of radical bands of quinone anions and aniline cations along with their formation and/or decay kinetics are used to confirm the electron transfer (ET) process. In MeCN medium, AN quenches the triplet state of CAQ (CAQT) but not the triplets AQTor AQST. However in aqueous medium, AN quenches AQSTand forms radical ion pair. All the DMAs can react through ET with all the triplet quinones at different degrees of efficiency in MeCN medium. Noticeably, the ring substituted DMAs are less efficient in electron donation to AQTor AQSTwhile the N,N-DMA shows high efficiency in donating electron to all triplet quinones in MeCN medium. Charge distribution of donor molecules, in MeCN medium is calculated using density functional theory (DFT), and shows an enhancement of electron density of the ring of N,N-DMA, making it an ideal electron donor for ET studies compared to other DMAs. This systematic selection and usage of anilines with electrochemically tunable quinones can be viewed as a working model of donor-acceptor system that can be utilized in photoinduced ET applications.
authors.affiliation: Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar.
authors.forename: V
authors.initials: V
authors.lastname: Sivakumar
authors.affiliation: Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar.
authors.forename: Deepalekshmi
authors.initials: D
authors.lastname: Ponnamma
authors.affiliation: Department of Chemistry & Earth Sciences, Qatar University, P.O. Box 2713, Doha, Qatar. Electronic address: cheyha@qu.edu.qa.
authors.forename: Yasser H A
authors.initials: YHA
authors.lastname: Hussein
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D000880:Anthraquinones / Q000737:chemistry*; D004583:Electrons; D055668:Photochemical Processes
chemical_list: D000814:Aniline Compounds; D000880:Anthraquinones; C023650:aniline
keywords: Aniline; Anthraquinone; Photoinduced electron transfer; Photolysis; Triplet quenching