Conformation of azo-bridge in 3,3′-dinitro-2,2′-azobipyridine and its 4,4′(or 5,5′ or 6,6′)-dimethyl-derivatives: Vibrational studies and DFT quantum chemical calculations
摘要:
Syntheses of 3,3'-dinitro-2,2'-azobipyridine and 4,4' (or 5,5' or 6,6')-dimethyl-3,3'-dinitro-2,2'-azobipyridine have been described. Molecular structures of these compounds have been determined and compared, to the basic compound, azobipyridine, reported by us earlier. The conformation of the azo-bond and other structural data are discussed in terms of substitution place of methyl chromophore. Fourier transform IR and Raman spectra of these compounds have been measured and analysed. The 6-311G (2d,2p) basis set with the B3LYP functional have been used to discuss the space conformation and dynamics of the studied compounds. (C) 2014 Elsevier B.V. All rights reserved.
The hydrazo-bond in 4,4′-dimethyl-3,3′-dinitro-2,2′-hydrazobipyridine – Crystal structure, conformation and vibrational characteristics
作者:E. Kucharska、I. Bryndal、J. Hanuza、T. Lis
DOI:10.1016/j.saa.2014.02.038
日期:2014.6
The crystal and molecular structure of 4,4'-dimethyl-3,3'-dinitro-2,2'-hydrazobipyridine have been determined by X-ray diffraction and quantum chemical OFT analysis. The title compound crystallizes in P (1) over bar space group, with one-half molecule in the asymmetric unit. The molecular structure is stabilized by intramolecular N-H center dot center dot center dot O hydrogen bonds. The molecules are linked by a combination of weak intermolecular C H center dot center dot center dot O interactions and also aromatic pi-pi stacking. The molecular structure of the studied compound has been determined using the DFT B3LYP/6-311G(2d,2p) approach and compared to that derived from X-ray studies. The IR and Raman wavenumbers have been calculated for the optimized geometry of a possible monomer structural model. The structural and vibrational properties of the intramolecular N-H center dot center dot center dot O interaction are described. (C) 2014 Elsevier B.V. All rights reserved.