title: Shedding light on the photostability of two intermolecular charge-transfer complexes between highly fluorescent bis-1,8-naphthalimide dyes and some π-acceptors: a spectroscopic study in solution and solid states.
abstract: Given the great importance of the various uses of 1,8-naphthalimides in the trends of biology, medicine and industry, the current study focused on extending the scope of these dyes by introducing some of their charge-transfer (CT) complexes. For this purpose, two highly fluorescent bis-1,8-naphthalimide dyes and their complexes with some π-acceptors have been synthesized and characterized spectroscopically. The π-acceptors include picric acid (PA), chloranilic acid (CLA), tetracyanoquinodimethane (TCNQ) and dichlorodicyanobenzoquinone (DDQ). The molecular structure, spectroscopic and fluorescence properties as well as the binding modes were deduced from IR, UV-vis and (1)H NMR spectral studies. The binding ratio of complexation was determined to be 1:1 according to the elemental analyses and photometric titrations. It has been found that the order of acceptance ability for the different acceptors is TCNQ>DDQ>CLA>PA. The photostability of 1,8-naphthalimide dye as a donor and its charge-transfer complex doped in polymethyl methacrylate/PMMA were exposed to UV-Vis radiation and the change in the absorption spectra was achieved at different times during irradiation period.
authors.affiliation: Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, 21974 Taif, Saudi Arabia; Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt. Electronic address: msrefat@yahoo.com.
authors.forename: Moamen S
authors.initials: MS
authors.lastname: Refat
authors.affiliation: Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt.
authors.forename: Lamia A
authors.initials: LA
authors.lastname: Ismail
authors.affiliation: Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, 21974 Taif, Saudi Arabia.
authors.forename: Abdel Majid A
authors.initials: AM
authors.lastname: Adam
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D010851:Picrates / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012996:Solutions; D013055:Spectrophotometry, Infrared; D014466:Ultraviolet Rays
chemical_list: D016227:Benzoquinones; D005456:Fluorescent Dyes; D009570:Nitriles; D010851:Picrates; D012996:Solutions; C013703:tetracyanoquinodimethane; C000928:dichlorodicyanobenzoquinone; D019904:Polymethyl Methacrylate; C005858:picric acid; C014400:chloranilic acid
keywords: 1,8-Naphthalimide dyes; Charge-transfer complex; Molecular structure; Photostability properties; Spectroscopic characterization