Structural and vibrational analyses of 2‐(2‐benzofuranyl)‐2‐imidazoline

Abstract

We have studied 2-(2-benzofuranyl)-2-imidazoline (BFI) and characterized it by using infrared and Raman spectroscopies. The density functional theory (DFT) method together with Pople's basis set shows that two conformers exist for the title molecule as have been theoretically determined in the gas phase and that, probably, an average of both conformations is present in the solid phase. The harmonic vibrational wavenumbers for the optimized geometry of the latter conformer were calculated at the B3LYP/6-31G * level in the proximity of the isolated molecule. For a complete assignment of the IR and Raman spectra in the compound in the solid phase, DFT calculations were combined with Pulay's scaled quantum mechanics force field (SQMFF) methodology in order to fit the theoretical wavenumbers to the experimental ones.

Structural study and characterization of the dipeptide 2-[[5-amino-5-oxo-2-(phenylmethoxycarbonylamino) pentanoyl] amino] acetic acid by vibrational spectroscopy and DFT calculations

“…In this compound, the strong IR band at 3400 cm À1 is assigned to this vibration mode. In similar compounds, the CAOH scissoring modes appear in the 1100-900 cm À1 region [27,[31][32][33][34][35][36][37][38][39]; thus, the IR band of medium intensity at 1122 cm À1 is assigned to this scissoring mode. The calculated SQM clearly predicted this mode at 1136 cm À1 .…”

“…For the L-ascorbic acid molecule, these stretching modes are assigned at 3523, 3409, 3316 and 3217 cm À1 [31][32][33][34]. In this compound, the strong IR band at 3400 cm À1 is assigned to this vibration mode.…”

“…Both forms of APPA have C 1 symmetry and 123 normal vibration modes, all active in the infrared and Raman spectra. The assignment of the experimental bands to the 123 expected normal vibration modes for both structures were made on the basis of the PED in terms of symmetry coordinates by using the B3LYP/6-31G * data and taking into account the corresponding assignment of related molecules [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Table 2 shows the observed frequencies and the assignment for both APPA structures.…”

A Comparative Study on the Structural and Vibrational Properties of Two Potential Antimicrobial and Anticancer Cyanopyridine Derivatives

“…The experimental and calculated wavenumbers for both derivatives together with the corresponding assignments are shown in Table 3. The vibrational assignments of the experimental bands to the normal vibration modes for both derivatives are based on the comparisons with related molecules [40]- [42] and with the results of the calculations performed here. In this work, we presented only the calculations for both derivatives in gas phase because the experimental spectra were not registered.…”

Vibrational and structural study of onopordopicrin based on the FTIR spectrum and DFT calculations

“…As part of our investigations on compounds that contain rings in their structures and exhibit important biological activities [1][2][3][4][5][6][7][8][9][10][11][12][13], in this work, we studied the structural and vibrational properties of onopordopicrin (OP), a sesquiterpene lactone isolated from the weed Centaurea tweediei. Onopordopicrin exhibits antimicrobial and cytotoxic activities, especially against human-derived macrophages [14] and against epidermoid carcinoma cells [15].…”