title: Spectrophotometric investigation of interaction between iodine and pentadentate Schiff base ligands.
abstract: The interaction between iodine as an electron acceptor (A), and three pentadentate Schiff bases, 1,3-bis(salicylideneamino)-2-propanol (SB1), 1,3-bis(2-hydroxy-1-naphthylideneamino)-2-propanol (SB2), and 1,3-bis[1-(pyridine-2-yl)methylideneamino]-2-propanol (SB3), as electron donor systems (D), was studied spectrophotometrically in methanol at 28 °C. Equilibrium constants K(AD) and molar extinction coefficients ε(AD) of the donor-acceptor complexes (AD) were determined using the modified Benesi-Hildebrand equation in conjunction with the non linear fit analysis. The method shows the formation of 1:1 type complexes as major species in solution. The free energy changes ΔG° and the energy of the charge transfer band E(CT) were also calculated for all complexes. The iodine complex derived from SB2 seems to be more stable than those derived from SB3 and SB1. On the other hand, the ionization potential I(D) of each Schiff base was estimated from the corresponding complex band energy, using an empirical equation. An inverse relationship between I(D) and K(AD) values was found. Blue and red shift observed for the 445 nm band of iodine were also discussed on the basis of theoretical considerations.
authors: Laboratoire de Chimie et d'Electrochimie des Complexes Métalliques (LCECM), Université des Sciences et de la Technologie d'Oran-Mohamed Boudiaf, BP 1505, El-Mnaouer 31000, Algérie; Unité Matériaux et Transformations (UMET), UMR CNRS N° 8207, Université Lille1 - Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France.
authors: Z
authors: Z
authors: Khouba
authors: Laboratoire de Chimie et d'Electrochimie des Complexes Métalliques (LCECM), Université des Sciences et de la Technologie d'Oran-Mohamed Boudiaf, BP 1505, El-Mnaouer 31000, Algérie.
authors: T
authors: T
authors: Benabdallah
authors: Unité Matériaux et Transformations (UMET), UMR CNRS N° 8207, Université Lille1 - Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France. Electronic address: ulrich.maschke@univ-lille1.fr.
authors: U
authors: U
authors: Maschke
mesh_terms: D000042:Absorption; D007455:Iodine / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D012545:Schiff Bases / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D008024:Ligands; D012545:Schiff Bases; D007455:Iodine
keywords: Benesi–Hildebrand; Charge transfer complex; Interaction; Ionization potential; Pentadentate Schiff base; Spectrophotometry