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In organisms, amino acids usually use water as a solvent which is an important component for cell formation. In this environment, the formation of intermolecular hydrogen bonds will affect the structure and properties of amino acids and water molecules. In order to study its properties in the ground state and excited state, in this paper, we use density functional theory（DFT) and time-dependent density functional theory（TD-DFT) to analyze the electrostatic potential, bond length, natural bond orbital（NBO) charge, Atoms In Molecules（AIM), Wiberg bond order b, infrared（IR) spectroscopy, hole-electron orbits of intermolecular hydrogen bonds between glycine and H2O in the ground and excited states, the hole electron orbit and the electron transfer between ground state and excited state are studied theoretically. The results show that the intermolecular hydrogen bond formation will lead to the change of molecular structure and the shift of infrared spectral vibration frequency. In the excited states, the intermolecular hydrogen bond is strengthened or weakened to different degrees. The results provide a theoretical basis for forming hydrogen bonds and the study of intermolecular hydrogen bonds in excited states. [ABSTRACT FROM AUTHOR]

Celecoxib is a highly selective inhibitor of COX-2. After 20 years of development, it has become the most widely used prescription drug in the world. This paper is based on density functional theory and uses B3LYP functional, 6-311++G (d,p) basis set for structural optimization. In this work, a series of studies have been done on the structure, infrared spectrum, Raman spectrum, molecular frontier orbital, electrostatic potential and excited state properties of the drug molecule. The results show that CXB molecule is a stable non-planar twisted structure, which allows the drug molecule to quickly pass through the hydrophobic channel on COX-2, thereby forming a binding cavity that can bind to the benzene-sulfonamide fragment. The frequency of the compound is calculated, the infrared spectrum and Raman spectrum are obtained respectively, which are compared with the data collected by the experiment, showing a high degree of consistency. The frontier orbital and electrostatic potential were analyzed for the ground state of the molecule, and the sulfonamide group and COX-2 were easy to form hydrogen bonds. In the study of the excited state of CXB molecule, it is found that the excited state property of CXB molecule is mainly determined by the first excited state, the third excited state and the sixth excited state. This provides important information for understanding the mechanism of action of CXB, and also provides a theoretical basis for later expansion of CXB derivatives. [ABSTRACT FROM AUTHOR]

A series of planar platinum complexes were studied by density functional theory. The ground state equilibrium geometry, absorption properties, excited state geometry, emission properties and charge transfer properties have been investigated, so as to summarize the substituent impact on the structure, frontier orbitals, spectral properties. The calculation results show that the lowest energy absorptions and emissions were composed of HOMO→LUMO transitions. The molecules with strong conjugation effect were suitable for the charge transport material, while the molecules with weak conjugation effect were suitable for the hole transport material. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)