Vibrational Spectroscopic Studies of Cocrystals and Salts. 3. Cocrystal Products Formed by Benzenecarboxylic Acids and Their Sodium Salts

Abstract

X-ray powder diffraction, differential scanning calorimetry, infrared absorption spectroscopy, and Raman spectroscopy have been used to study the phenomenon of salt formation in four benzenecarboxylic acids (benzoic acid, phenylacetic acid, hydrocinnamic acid, and 4-phenylbutanoic acid), and in the 1:1 stoichiometric products formed by the cocrystallization of a free acid and a sodium salt. Assignments were derived for the observed peaks in both infrared absorption and Raman spectra of the reactants and their products. In all instances, it was observed that the energy of the antisymmetric stretching mode of the carbonyl group of the free benzenecarboxylic acid invariably shifted to higher energies when that acid formed a cocrystal with a sodium salt of another benzenecarboxylic acid. In addition, the symmetric stretching mode of the benzenecarboxylic acid carbonyl group disappeared in the Raman spectrum of its sodium salt and was also absent in the Raman spectrum of the cocrystal product. It was also found that the antisymmetric carboxylate anion stretching mode, the symmetric carboxylate anion stretching mode, the out-of-plane carboxylate deformation mode, and the vibrational modes associated with the phenyl ring and alkane side chains were not useful spectroscopic tools to differentiate cocrystal and sodium salt, as the observed differences of these vibrational modes did not exhibit significantly consistent differences between the various forms.

Half-Sandwich Ru(II) Halogenido, Valproato and 4-Phenylbutyrato Complexes Containing 2,2′-Dipyridylamine: Synthesis, Characterization, Solution Chemistry and In Vitro Cytotoxicity

“…830 cm −1 belong to the ν(P-F) vibrations [19]. The peaks assignable to the characteristic vibrations of the VP (e.g., 2930, 1640 or 1380 cm −1 ) and PB (e.g., 2970, 1640, 1385 or 1300 cm −1 ) ligands [20,21] clearly showed in the FTIR spectra of the complexes 4 and 5. The peaks whose mass corresponded to the complex cations, i.e., [Ru(p-cym)(dpa)X] + , of the studied complexes 1-5 were detected in the ESI+ mass spectra (Figure 2).…”

Vibrational Spectroscopic Studies of Cocrystals and Salts. 4. Cocrystal Products formed by Benzylamine, α-Methylbenzylamine, and their Chloride Salts

“…10 In the present work, the scope of potential salt-cocrystal products has been extended, with phenylalkylamine precursors being shown to form (in most instances) salt-cocrystal products with phenylalkylammonium chloride salts.…”

“…In the latter system, assignments for all vibrational modes in the saltcocrystal products could be made on the basis of the assignments for the individual components. 9,10 This would imply the vibrational modes of the components in the benzenecarboxylic acid/ sodium salt systems largely retain their individual patterns of molecular motion. On the other hand, a number of vibrational modes in phenylalkylamine salt-cocrystals had no precursor in the spectra of either the free amine or the amine salt, and the existence of the modes would signify the existence of more delocalization in the vibrational patterns of this latter system.…”

“…8 In this laboratory, vibrational spectroscopy has been used to study intermolecular interactions in the 1:1 salt-cocrystal formed by the interaction of benzoic acid with benzylammonium benzoate, 9 as well as the salt-cocrystal products formed by a series of benzenecarboxylic acids and their sodium salts. 10 Whereas the aforementioned studies investigated the phenomenon of salt-cocrystal formation among acidic substances and their salts, the present study is concerned with the formation of salt-cocrystal products resulting from the interaction of basic substances with their corresponding acid addition salts. Thus, the present study relates to the scope of intermolecular interactions existing in these systems containing different modes of anion coordination and anion-templated assemblies.…”

Solid State Characterization of a Novel Physical Interaction (Paracetamol-Chlorpheniramine Maleate)

“…5) indicated a shifting on spectrum of CTM purely as compared to the CTM in the mixture, its tends to increase the intensity of the sharp, whereas in the un-diluted PCT tend intensity obtained PCT tends not to undergo much change in the intensity of its incorporation in spectrum [22]. The shifting of the wavenumber from spectrum exhibited the interaction in material in solid state [23]. Result of spectrum overlay from PCT, CTM and it mixture, it's exhibited the shifting of C-H stretching in 3000 cm -1 and C=O in wavelength 1760 cm -1 .…”