Quantum mechanical/molecular mechanical approach for the simulation of UV–Vis absorption spectra of π-conjugated oligomers

Rashid, Al Mamunur; Ahn, Kyusang; Jeon, Jonggu; Cho, Minhaeng; Kim, BongSoo; Lee, Kyungkoo; Kwak, Kyungwon

doi:10.1016/j.molliq.2021.117406

Cited by 2 publications

(1 citation statement)

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“…These calculations were used to determine the gaseous phase heat capacities for all species at 298.15 K, using the recommended frequency scaling factor of 0.9567, and evaluated gas phase molecular geometries and energetics. In addition, TD-DFT at the M06-2X/6-311++G(d,p) level of theory was employed to simulate the UV–vis spectra of the phenylimidazoles studied by calculating the excitation energies and oscillator strengths considering 8 to 16 excited states. − The UV–vis absorption spectra were simulated by assuming a Gaussian band shape with a peak width of 0.4 eV. The polarizable continuum model (PCM) was used to simulate the solvent effect (CH 2 Cl 2 ) .…”

Section: Methodsmentioning

confidence: 99%

The Cohesive Interactions in Phenylimidazoles

Costa,

Lobo Ferreira,

Lima

et al. 2024

J. Phys. Chem. A

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This work presents a comprehensive study exploring the thermodynamics of the solid phase of a series of phenylimidazoles, encompassing experimental measurements of heat capacity, volatility, and thermal behavior. The influence of successive phenyl group insertions on the imidazole ring on thermodynamic properties and supramolecular behavior was thoroughly examined through the evaluation of 2-phenylimidazole (2-PhI), 4-phenylimidazole (4-PhI), 4,5-diphenylimidazole (4,5-DPhI), and 2,4,5-triphenylimidazole (2,4,5-TPhI). Structural correlations between molecular structure and thermodynamic properties were established. Furthermore, the investigation employed UV−vis spectroscopy and quantum chemical calculations. Additive effects arising from the introduction of phenyl groups were found through the analysis of the solid−liquid and solid−gas equilibria, as well as heat capacities. A good correlation emerged between the thermodynamic properties of sublimation and the molar volume of the unit cell, evident across 2-PhI, 4,5-DPhI, and 2,4,5-TPhI. In contrast to its isomer 2-PhI, 4-PhI exhibited greater cohesive energy due to the stronger N−H•••N intermolecular interactions, leading to the disruption of coplanar geometry in the 4-PhI molecules. The observed higher entropies of phase transition (fusion and sublimation) are consistent with the higher structural order observed in the crystalline lattice of 4-PhI.

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