title: Spectroscopic insights on selfassembly and excited state interactions between rhodamine and phthalocyanine molecules.
abstract: The absorption and fluorescence spectra as well as fluorescence lifetimes of tetrasulfonated zinc phthalocyanine ZnPc(SO3Na)4 were measured in the absence and presence of four rhodamine dyes, Rhodamine B (RB), Ethyl rhodamine B (ERB), Rhodamine 6G (R6G), Rhodamine 110 (R110), and Pyronine B (PYB). The ground state complexes of phthalocyanine-(Rhodamine)2 were observed which exhibit new absorption bands. The binding constants are all very large (0.86×10(5)-0.22×10(8) M(-1)), suggesting rhodamine-phthalocyanine pairs are very good combinations for efficient selfassembly. Both the fluorescence intensity and the lifetime values of ZnPc(SO3Na)4 were decreased by the presence of rhodamines. The structural effect of rhodamines on selfassembly is significant. The ground state binding and dynamic quenching capability is PYB>R6G>ERB>RB>R110. The dynamic fluorescence quenching is due to the photoinduced electron transfer (PET). The PET rate constant is very large and in the order of 10(13) M(-1) s(-1), much greater than kf and kic (in the order of 10(8) M(-1) s(-1)), which means that the PET efficiency is almost 100%. Therefore the non-covalent Pc-rhodamine is a very good pair of donor/acceptor for potential efficient solar energy conversion.
authors.affiliation: Institute of Applied Photochemistry & Center of Analysis and Measurements, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province 066004, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Geng
authors.affiliation: Institute of Applied Photochemistry & Center of Analysis and Measurements, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province 066004, China; MPC Technologies, Hamilton, ON L8S 3H4, Canada. Electronic address: zhangxianfu@tsinghua.org.cn.
authors.forename: Xian-Fu
authors.initials: XF
authors.lastname: Zhang
mesh_terms: D065966:Absorption, Physicochemical; D004396:Coloring Agents / Q000737:chemistry; D004583:Electrons; D007211:Indoles / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D009942:Organometallic Compounds / Q000737:chemistry*; D011754:Pyronine / Q000031:analogs & derivatives; D012235:Rhodamines / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D004396:Coloring Agents; D007211:Indoles; D009942:Organometallic Compounds; D012235:Rhodamines; D012996:Solutions; C026188:rhodamine 6G; C049025:rhodamine 110; C063072:zinc(II) phthalocyanine trisulfonic acid; C029773:rhodamine B; C012020:pyronine B; D011754:Pyronine
keywords: Absorption spectra; Fluorescence quenching; Phthalocyanine; Rhodamine; Selfassembly