197803-92-2Relevant academic research and scientific papers
Vibrational and theoretical study of the 2',6'-dimethoxyflavone cis-formic acid inclusion compound.
Vrielynck,Wallet,Merlin
, p. 2439 - 2450 (2007/10/03)
The FT-infrared and Raman microscopy spectra of the 2',6'-dimethoxyflavone and its 1:1 complex with formic acid in solid state have been recorded and analysed. Some vibrational components appear as specific to the cis-rotamer of formic acid in the crystalline sample, especially the CH group stretching vibration feature. The broad and intense infrared absorption observed in the range 3400-1900 cm(-1) and assigned to the hydrogen bonded OH group stretching vibration exhibits the characteristic ABC structure of strong hydrogen bonded complexes. This ABC pattern corroborates previous X-ray crystallographic data showing that cis-formic acid is strongly hydrogen bonded to the flavonic compound. The inclusion complex is quite unstable and the infrared spectrum clearly shows that formic acid disappears after a period of a few months. In order to get some information on the stability criterions of the intermolecular hydrogen bonded complex, semiempirical AM1 calculations have been investigated. The comparison of the calculated heats of complexation (deltacH) for chelates involving the cis- and trans-conformers of formic acid suggests that the reaction of hydrogen bonding complexation with the cis-rotamer is surely favoured.
Study of the Conformational Equilibria of Some 2-(2′-Hydroxyphenyl)-4-aryl-3H-1,5-benzodiazepines using 1H, 13C, and 15N NMR Spectroscopy
Ahmad,Zia-ul-Haq,Duddeck,Stefaniak,Sitkowski
, p. 633 - 640 (2007/10/03)
Variable temperature 1H NMR experiments of 2-(2′-hydroxyphenyl)-4-phenyl-3H-1,5-benzodiazepine (5a) and its derivatives 5d and 5e were carried out in order to investigate the conformational behaviour of these compounds. The ΔG* values for the r
