FT-IR and Raman vibrational analysis, B3LYP and M06-2X simulations of 4-bromomethyl-6-tert-butyl-2H-chromen-2-one

Abstract

h i g h l i g h t sThe FT-IR and Raman spectra of the title compound were recorded in solid phase. The optimized geometry and vibrational frequencies were calculated for the first time. The complete assignments are performed on the basis of the potential energy distribution (PED). The HOMO-LUMO energies and related molecular properties were evaluated.

Effect of the sulfur atom on S2 and S4 positions of the uracil ring in different DNA:RNA hybrid microhelixes with three nucleotide base pairs

“…In general, DFT methods appear as the most suitable today because they offer a compromise between the important demands put on computer power and time, and the desired chemical accuracy. Furthermore, these methods have been used satisfactorily in many spectroscopic studies, in nucleosides, DNA base pairs, water cluster of nucleobases, biological molecules, and in drug designing, in particular the M062X method selected here …”

The effect of chalcogen substitution on the structure and spectroscopy of 4,7-dimethyl-2H-chromen-2-one/thione analogues

“…The analysis of the Raman spectra allows for a clear assignment of the C-C stretching modes in the benzopyrone ring, with signals at 1559, 1512 and 1412 cm -1 . 14,45 (14) a' / ν as CH 3 -Ph (82) 3079 (9) a''/ν as CH 3 -Py (100) 3076 (13) a''/ν as CH 3 -Ph (100) 3030 (11) a'/ ν s CH 3 -Py (99) 3027 (25) a'/ ν s CH 3 247(<1) a'' / γ C 4 C 10 C 5 C 9 (56); γ C 3 C 4 C 10 C 12 (16); τ C 5 C 6 C 7 C 8 (27) 220(1) a' / δCC (43); δ O-C 9 -C 8 (16) 204 m 205(2) a'' / τ H-C 12 -C 4 -C 10 (68); τ C 3 -C 4 -C 10 -C 9 (32) 171 w 167(<1) a'' / τ C3-C4-C10-C9 (51); γ C-CH3 Py(29) 117 w 100(<1) a'' / τ C 2 -O-C 9 -C 8 (43); τ C 6 -C 7 -C 8 -C 9 (24); γ OC 10 -C 8 -C 9 (23) 89(2) a'' / τ C 2 -O-C 9 -C 10 (46); τ C 7 -C 8 -C 9 -C 10 (35); τ C 5 -C 6 -C 7 -C 8 (18) 43(<1) a'' / τ C-CH 3 Ph (84); γ C 13 -C 6 -C 8 -C 7 (11) a Band intensities and shape: vs = very strong; s = strong; m = medium; w = weak; vw = very weak, sh: shoulder, br: broad. b In parenthesis computed IR intensities in Km/mol are given.…”

Vibrational assignments, spectroscopic investigation (FT-IR and FT-Raman), NBO, MEP, HOMO‒LUMO analysis and intermolecular hydrogen bonding interactions of 7-fluoroisatin, 7-bromoisatin and 1-methylisatin ‒ A comparative study

“…The low value of gap represents the high reactivity of the molecule in chemical reactions [114]. Also, the lowering of the energy gap describes that the eventual charge transfer takes place within the molecule [106]. This clearly indicates that more charge transfer appears within the 1-methylisatin molecule than the others (7-br-1 and 7-fl-1), leading to increase the molecular reactivity of 1-methylisatin.…”

“…The C-Br stretching and C-Br deformation modes were determined by the researchers in the regions 650-485 cm -1 [83, 104] and 300-140 cm -1 , respectively [83, 105]. For the 4-bromomethyl-6-tert-butyl-2H-chromen-2-one, the C-Br stretching vibrations were detected by Sert et al at 574 (IR) / 576 (Ra), 521 (IR) / 523 (Raman), 472 (IR) / 461 (Raman) and 174 (Raman) cm -1 with the aid of the experimental spectra[106]. In the current study, the C-Br stretching vibrations were…”