Synthesis and Structural Characterization of Charge-Transfer Complexes Derived from Three Symmetrically Substituted 4,4-Bis-(1,3,5-Triazinylamino)Stilbene-2,2-Disulfonate Derivatives with some -Acceptors. Part One : Chloranilic AcidAuthor(s): Moamen S. Refat, Lamia A. Ismail and Abdel Majid A. Adam
Fluorescent brighteners (FBs) have become a part of everyday life and culture. One important class of fluorescent brighteners (FBs) is triazine-stilbene derivatives, which are widely used to create intense and bright white shades in textiles, pulps and papers. It is possible to improve the chemical and physical properties of triazine-stilbene derivatives by studying their complexation behavior. For this purpose, three new charge-transfer complexes were obtained by the interaction between three symmetrically substituted 4,4′-bis-(1,3,5-triazinylamino)stilbene-2,2′-disulfonate derivatives with chloranilic acid. The structures of these complexes were characterized by using elemental analysis, IR and electronic absorption spectroscopy. Based on elemental analyses and photometric titrations, the stoichiometry of the complexes (donor : acceptor molar ratios) was determined to be 1 : 2 for all three complexes. The formation constant (KCT), molar extinction coefficient (εCT) and other spectroscopic data have been determined using the Benesi–Hildebrand method and its modifications.