title: Noncovalent binding of xanthene and phthalocyanine dyes with graphene sheets: the effect of the molecular structure revealed by a photophysical study.
abstract: The fluorescence and absorption properties of several xanthene and phthalocyanine dyes were measured in the presence and absence of chemically derived graphene (CDG) sheets. The interaction of pyronine Y (PYY) with graphene sheets was compared with that of rhodamine 6G (R6G) to reveal the effect of the molecular structure. Although the presence of the perpendicular benzene moiety in a R6G or phthalocyanine molecule does cause the difficulty for forming dye-CDG complex and make CDG less efficient in quenching the fluorescence intensity and shortening the fluorescence lifetime, it does not affect the band position of charge transfer absorption, suggesting that no molecular shape change occurred in a dye molecule caused by the interaction with CDG sheets. The spectroscopic and thermodynamic data indicated that the dye-CDG binding is of charge transfer nature, while the dynamic fluorescence quenching is due to photoinduced energy and electron transfer.
authors.affiliation: Chemistry Department, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province 066004, China. zhangxianfu@tsinghua.org.cn
authors.forename: Xian-Fu
authors.initials: XF
authors.lastname: Zhang
authors.forename: Su-Ping
authors.initials: SP
authors.lastname: Liu
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Shao
mesh_terms: D000042:Absorption; D004396:Coloring Agents / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry; D005453:Fluorescence; D006108:Graphite / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D008027:Light; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D008968:Molecular Conformation; D055585:Physical Phenomena; D011754:Pyronine / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014966:Xanthenes / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D007211:Indoles; D054833:Isoindoles; D012235:Rhodamines; D014966:Xanthenes; C026188:rhodamine 6G; D014867:Water; D006108:Graphite; D019793:Fluorescein; C013647:phthalocyanine; D011754:Pyronine
keywords: Fluorescence quenching; Graphene; Phthalocyanine; Rhodamine; π−π Interaction