Charge‐Transfer Complex of p‐Aminodiphenylamine with Maleic Anhydride: Spectroscopic, Electrochemical, and Physical Properties

Abstract

A new charge-transfer complex and the amide formed by the interaction between the electron donor of the p-aminodiphenylamine and the electron acceptor of maleic anhydride are investigated by spectroscopic methods. The amidation reaction is caused by proton and charge transfer between the maleic anhydride and p-aminodiphenylamine molecules. The Benesi-Hildebrand equation is used to determine the formation constant, the molar extinction coefficient and the standard Gibbs free energy of the complex by using UV/Vis spectroscopy. To reveal the electronic and spectroscopic properties of these molecules, theoretical computations are performed on the structures of maleic anhydride, p-aminodiphenylamine and the conformers of their charge-transfer complex. The charge-transfer complex and amidation reaction mechanism are also confirmed by IR and NMR spectroscopy and HRMS. The nature of the maleic anhydride-p-aminodiphenylamine complex is characterized by cyclic voltammetry, thermogravimetric analysis, XRD and SEM. Solid microribbons of this complex show higher thermal stability than p-aminodiphenylamine.

Electrochemical Properties and Excited-State Dynamics of Azaperylene Derivatives

“…The path-length of the employed cuvette is 1 cm. The binding constants were calculated using the Benesi–Hildebrand equation, − [A]/Abs = (1/[TFA])­(1/ εK ) + (1/ε), where [A] is the total concentration of bound and unbound azaperylene derivatives and is kept fixed, Abs is the absorbance of the complex at the wavelength λ, [TFA] is the total concentration of the TFA, which is varied, K is binding constant, and ε is the molar absorptivity of the protonated azaperylene complex at the excitation wavelength λ. Benesi–Hildebrand analysis gives a linear plot indicating that a 1:1 complex is formed, and the slope yields a binding constant K = 6.9 × 10 3 M –1 showing that the protonated form has a high degree of stability. The K values of other azaperylenes are summarized in Table .…”

Sequence-Controlled Polyurethane Block Copolymer Displays Differentiated Immunoglobulin-G Adsorption That Influences Human Monocyte Adhesion and Activity

“…To assess the potential of forming alternating sequences of MA and EVE during the polymerization of D-PHI, mixtures of both unreacted monomers, in the absence of DVO, were first analyzed by 1 H NMR. It is important to note that mixtures of EVE and MA show additional peaks (Figures c–f and S3 of the Supporting Information, SI) alongside those corresponding to each of the pure monomers (Figures a,b, S1, S2), indicating the formation of charge transfer complexes where the participating monomers’ proton signals are shifted from their original locations. , The particular peaks in question are visible as the doublet of doublets with peaks in the ranges of 6.43–6.45, 6.40–6.42, 6.36–6.38, and 6.33–6.35 ppm and the doublet in the range of 6.39–6.42 ppm (Figure c–f) as well as at 6.00–6.04 ppm, 3.76–3.82 ppm, 3.52–3.65 ppm at 3.42–3.50 ppm, 1.39–1.41 ppm, and 1.13–1.21 ppm (Figure S3).…”

“…Experiments performed with monocytes were repeated with three distinct donors. 25,26 The particular peaks in question are visible as the doublet of doublets with peaks in the ranges of 6.43−6.45, 6.40−6.42, 6.36−6.38, and 6.33−6.35 ppm and the doublet in the range of 6.39−6.42 ppm (Figure 2c−f) as well as at 6.00− 6.04 ppm, 3.76−3.82 ppm, 3.52−3.65 ppm at 3.42−3.50 ppm, 1.39−1.41 ppm, and 1.13−1.21 ppm (Figure S3).…”