Molecular structure, spectroscopic properties and quantum chemical calculations of 8-t-buthyl-4-methyl-2H-chromen-2-one

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

“…The second band at 276 nm is associated with two very close transitions computed at 274 and 271 nm associated with HOMO-2→ LUMO (92%) and HOMO-1→ LUMO (70%) for the compound 1. This assignment is in agreement with recently reported spectra of related coumarins 44 and chromones. 42,48 The UV-Vis spectrum for compound 2 shows intense and broad band centered at 377 nm, with a shoulder clearly observed at 394 nm and the non-symmetric tail toward the highwavenumber region suggest the presence of a absorption occurring at ca.…”

“…The 3N-6 = 63 normal modes of vibration can be classified as 41 A' in-plane modes and 22 A'' out-of-plane modes in the C S symmetry group computed for the vaccum isolated molecule. The assignment of the bands was determined from the normal coordinate analysis aided by visualization of the animations for displacement vectors of localized vibrational modes andcomplemented by comparison with spectra of related molecules [42][43][44][45]. The joint analysis of the infrared and Raman spectra allows for a complete description of the vibrational properties of compounds 1 and 2, which is in good agreement with the harmonic frequencies obtained with the B3LYP/6-311++G(d,p) level of calculations.…”

“…Finally, the νC=C stretching modes of the bencene system originate a series of intense absorptions at 1623, 1603 and 1537 cm -1 , the last two bands with strong counterparts in the Raman spectrum of compound 2 at 1596 and 1537 cm -1 , respectively. 2a' / δ C-C ring Ph (44); τ H-C 13 -C 7 -C 8 (55) 893(0.03) a'' / ρ H-C 3 -C 2 -C 13 (72); ρ H-C 8 -C 7 -C 13 (28) 889 (8) a' / ν CC ring Py (58); ν CO (42) 885 (27) a'' / ρ H-C 13 -C 7 -C 8 (76); ρ H-C 3 -C 4 -C 12 (24) a'' / ρ H-C 13 -H (95) 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.…”

Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

“…The differences between the calculated and the experimental values can be explained by the fact that the classical hydrogen bonding ( Table 3) causing polarization of the bonds, along with the protonation of the phen N atom as causing electron deficient at the certain position such as ortho and para positions, and also close stacking as an anti-parallel fashion where the amino groups can act as an electron donating group in dimer in addition to π-π interactions between the two planes. The solvent influence and also polarity of the solvent should take into account for the differences as revealed in similar cases [70].…”

4-Klorometil-6,8-dimetilkumarin Bileşiğinin Sentezi ve Teorik Kimyasal Hesaplamaları

“…Mulliken yükdağılım metodu molekülün polarlığı, elektronik yapısı, atomik yapıların dipolmomenti, atomlar üzerindeki yük dağılımı, moleküldeki yük transferini sağlayan donor ve acceptor çiftleri ve moleküler yapıların farklı özellikleri hakkında geniş biçimde bilgi sağladığı için çok yaygın olarak kullanılan bir metodtur [12]. C8 karbon atomunun mulliken atomik yükdeğeri diğer karbon atomlarına oranla daha yüksek hesaplanmıştır ki bunun nedeni komşu atomlarının (O7 ve O13) önemli ölçüde elektronegatif özelliğe sahip olmasıdır.…”