The role of ring substituents on hydrogen bonding of 5-cyano-2-hydroxyacetophenone and 2-hydroxy-4-methoxy-5-nitroacetophenone in the ground and excited states

Synthesis, structural elucidation and DFT studies of ortho-hydroxy acetophenones

“…In (1), the planarity of the hydrogen bonded molecular fragment passing through the hydrogen bond O2B-H2BÁÁÁO3B is largely deviated from the least square mean planes of the aromatic ring by 1.79(1)°and that for (2) Table 2) are similar to those found in analogous structures. These bond distances do not vary significantly despite the differing intermolecular interaction patterns observed in various compounds [19,[31][32][33][34][35]. Due to involvement in hydrogen bonding also the carbonyl C@O bonds lengths [1.255(4)-1.258(4) Å in (1) and 1.247(2)-1.254(2) Å in (2)] are somewhat longer than those reported earlier [32,36] but agree well with [31,33,37].…”

“…Over the years much effort has been concentrated on characterization of hydrogen bonded systems in order to provide parameters to describe hydrogen bond strength and geometry [8][9][10][11][12][13]. The investigations in hydrogen bonding of ortho-hydroxy acetophenones [14][15][16][17][18][19] proved that the greatest steric impact of a substituent on the hydrogen bridge length is with substitution at the phenyl ring of the ortho-hydroxy acetophenones. As part of our ongoing studies to elucidate the relationships between the characteristics of the functional dyes containing acetophenone skeletons and their molecular structures and to investigate the possibilities for interand intramolecular hydrogen bonding in the solid state, the Xray structure analyses were undertaken.…”

Some Brief Notes on Theoretical and Experimental Investigations of Intramolecular Hydrogen Bonding

“…Ortho -hydroxyaryl aldehydes and ketones are structurally close to ortho -hydroxyaryl Schiff bases, but they do not display proton transfer in the ground state [60,61,62]. The studies of two derivatives of ortho -hydroxyacetophenone (5-cyano-2-hydroxyacetophenone and 2-hydroxy-4-methoxy-5-nitro-acetophenone) [62] which possess markedly strong acidity of the hydroxyl group failed to show the existence of the PT form in the ground state. Moreover, the investigation of fluorescent spectra recorded in solution and in the solid state show the prevailing of the PT form in the excited state for the ortho -hydroxyacyl aromatic compounds [63,64,65].…”

Ab initio and density functional theory studies on vibrational spectra of 3-{[(4-methoxyphenyl)methylene]amino}-2-phenylquinazolin-4(3H)-one

“…For the title compound, the bond lengths of the methoxy group C23-O40=1.3865 Å and O40-C41=1.4532 Å, whereas the reported values of similar derivatives are 1.350 Å (DFT), 1.3245 Å (XRD) and 1.442 Å (DFT), 1.4376 Å (XRD) [41]. Filarowski et al [42] reported the corresponding values as 1.3422 Å (XRD), 1.3391 Å (DFT) and 1.4473 Å (XRD), 1.4306 Å (DFT) and Castneda et al [27] reported these values in the range 1. [27].…”