Structure and intermolecular hydrogen bond of jet-cooled p-aminophenol–(H2O)1 studied by electronic and IR-dip spectroscopy and density functional theory calculations

2002 ◽  
Vol 277 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Hirotoshi Mori ◽  
Hitomi Kugisaki ◽  
Yoshiya Inokuchi ◽  
Nobuyuki Nishi ◽  
Eisaku Miyoshi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Density Functional Theory Calculations ◽  
Functional Theory

Molecular structure, spectroscopic signatures and reactivity analyses of paracetamol hydrochloride monohydrate salt using density functional theory calculations

CrystEngComm ◽  
2018 ◽  
Author(s):  
Karnica Srivastava ◽  
Anuradha Shukla ◽  
Karthick Thangavel ◽  
Sitaram Velaga ◽  
Poonam Tandon ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Hydrogen Bond Interactions ◽  
Hydrochloride Monohydrate ◽  
Spectroscopic Signatures

The aim of the present study is to understand the role of intermolecular hydrogen bond interactions present in the paracetamol hydrochloride monohydrated salt. Paracetamol hydrochloride monohydrate salt (PRA-HCl), along with...

scholarly journals Hydrogen-bonding study of photoexcited 4-nitro-1,8-naphthalimide in hydrogen-donating solvents

Open Physics ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 621-627
Author(s):  
Jianfang Cao ◽  
Hongmei Wu ◽  
Yue Zheng ◽  
Fangyuan Nie ◽  
Ming Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Excited States ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Excitation Energies ◽  
Hydrogen Bond Acceptor ◽  
Functional Theory ◽  
Electronically Excited ◽  
Hydrogen Bonded

AbstractThe solute–solvent interactions of 4-nitro-1,8-naphthalimide (4NNI) as a hydrogen bond acceptor in hydrogen donating methanol (MeOH) solvent in electronic excited states were investigated by means of the time-dependent density functional theory(TDDFT). We calculated the S0 state geometry optimizations, electronic transition energies and corresponding oscillation strengths of the low-lying electronically excited states for the isolated 4NNi and hydrogen-bonded 4NNi-(MeOH)1,4 complexes using the density functional theory (DFT) and TDDFT methods. The electronic excitation energies of the hydrogen-bonded complexes are correspondingly decreased compared to that of the isolated 4NNi, which revealed that the intermolecular hydrogen bond C=O···H–O and N=O···H–O in the hydrogen-bonded 4NNi-(MeOH)1,4 are strengthened in the electronically excited state. The calculated results are consistent with the mechanism that hydrogen bond strengthening will induce a redshift of the corresponding electronic spectra, while hydrogen bond weakening will cause a blueshift. Furthermore, we believe that the deduction we used to depict the trend of the hydrogen bond changes in excited states exists in many other fuorescent dyes in solution.

scholarly journals Structural and Reactivity Analyses of Nitrofurantoin–4-dimethylaminopyridine Salt Using Spectroscopic and Density Functional Theory Calculations

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 413 ◽  
Author(s):  
Eram Khan ◽  
Anuradha Shukla ◽  
Karnica Srivastava ◽  
Debraj Gangopadhyay ◽  
Khaled H. Assi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Density Functional Theory Calculations ◽  
Active Pharmaceutical Ingredient ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Ft Raman Spectroscopy ◽  
Stretching Vibration ◽  
Ft Ir

Pharmaceutical salt, nitrofurantoin–4-dimethylaminopyridine (NF-DMAP), along with its native components NF and DMAP are scrutinized by FT-IR and FT-Raman spectroscopy along with density functional theory so that an insight into the H-bond patterns in the respective crystalline lattices can be gained. Two different functionals, B3LYP and wB97X-D, have been used to compare the theoretical results. The FT-IR spectra obtained for NF-DMAP and NF clearly validate the presence of C33–H34⋅⋅⋅O4 and N23–H24⋅⋅⋅N9 hydrogen bonds by shifting in the stretching vibration of –NH and –CH group of DMAP+ towards the lower wavenumber side. To explore the significance of hydrogen bonding, quantum theory of atoms in molecules (QTAIM) has been employed, and the findings suggest that the N23–H24⋅⋅⋅N9 bond is a strong intermolecular hydrogen bond. The decrement in the HOMO-LUMO gap, which is calculated from NF → NF-DMAP, reveals that the active pharmaceutical ingredient is chemically less reactive compared to the salt. The electrophilicity index (ω) profiles for NF and DMAP confirms that NF is acting as electron acceptor while DMAP acts as electron donor. The reactive sites of the salt are plotted by molecular electrostatic potential (MEP) surface and calculated using local reactivity descriptors.

Theoretical study of the ground and excited states of 1-methylamideanthraquinone and its complex with fluoride anion

2016 ◽  
Vol 15 (04) ◽  
pp. 1650033
Author(s):  
Bing-Qiang Wang ◽  
Xiao-Fen Yin ◽  
Yan-Yun Dong ◽  
Cai-Yun Zhang
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Proton Transfer ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Emission Spectra ◽  
Intramolecular Proton Transfer ◽  
Fluoride Anion ◽  
Functional Theory ◽  
Intramolecular Hydrogen

We have performed a series of calculations using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) for 1-methylamideanthraquinone (MAAQ). In the S0 state of MAAQ, amide group is coplanar with anthraquinone, and an intramolecular hydrogen bond [Formula: see text] is formed. The [Formula: see text] transition has an intramolecular charge transfer character. Two stable structures (planar nMAAQ and twisted tMAAQ) have been obtained in the S1 state of MAAQ. Thereinto, nMAAQ is lower by 0.105[Formula: see text]eV than tMAAQ in energy, so nMAAQ is the dominant conformation in the S1 state of MAAQ and the emission spectra of tMAAQ cannot be observed in the solution of MAAQ. Excited state intramolecular proton transfer (ESIPT) between C[Formula: see text]O and N–H was not observed in the S1 state of MAAQ. Upon addition of fluoride anion, only twisted conformations were obtained in both S0 and S1 states of MAAQ-F[Formula: see text]. An intermolecular hydrogen bond [Formula: see text] is formed in the S0 state, and intermolecular proton transfer happens in the S1 state for MAAQ-F[Formula: see text].

An X-ray crystallographic and density functional theory study of (3Z)-4-(5-ethylsulfonyl-2-hydroxyanilino)pent-3-en-2-one and (3Z)-4-(5-tert-butyl-2-hydroxyanilino)pent-3-en-2-one

2013 ◽  
Vol 69 (3) ◽  
pp. 258-262
Author(s):  
Kate J. Akerman ◽  
Orde Q. Munro
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
Density Functional ◽  
Intermolecular Hydrogen Bond ◽  
Functional Theory ◽  
One Dimensional ◽  
X Ray ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonded

The Schiff base enaminones (3Z)-4-(5-ethylsulfonyl-2-hydroxyanilino)pent-3-en-2-one, C13H17NO4S, (I), and (3Z)-4-(5-tert-butyl-2-hydroxyanilino)pent-3-en-2-one, C15H21NO2, (II), were studied by X-ray crystallography and density functional theory (DFT). Although the keto tautomer of these compounds is dominant, the O=C—C=C—N bond lengths are consistent with some electron delocalization and partial enol character. Both (I) and (II) are nonplanar, with the amino–phenol group canted relative to the rest of the molecule; the twist about the N(enamine)—C(aryl) bond leads to dihedral angles of 40.5 (2) and −116.7 (1)° for (I) and (II), respectively. Compound (I) has a bifurcated intramolecular hydrogen bond between the N—H group and the flanking carbonyl and hydroxy O atoms, as well as an intermolecular hydrogen bond, leading to an infinite one-dimensional hydrogen-bonded chain. Compound (II) has one intramolecular hydrogen bond and one intermolecular C=O...H—O hydrogen bond, and consequently also forms a one-dimensional hydrogen-bonded chain. The DFT-calculated structures [in vacuo, B3LYP/6-311G(d,p) level] for the keto tautomers compare favourably with the X-ray crystal structures of (I) and (II), confirming the dominance of the keto tautomer. The simulations indicate that the keto tautomers are 20.55 and 18.86 kJ mol−1lower in energy than the enol tautomers for (I) and (II), respectively.

scholarly journals Density Functional Theory (DFT) and Natural Bond Orbital (NBO) Analysis of Intermolecular Hydrogen Bond Interaction in "Phosphorylated Nata De Coco - Water"

2018 ◽  
Vol 18 (1) ◽  
pp. 173 ◽  
Author(s):  
Sitti Rahmawati ◽  
Cynthia Linaya Radiman ◽  
Muhamad Abdulkadir Martoprawiro
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Intermolecular Hydrogen Bond ◽  
Lone Pair ◽  
Basis Set ◽  
Proton Acceptor ◽  
Functional Theory

This study aims to study the conformation, the hydrogen bond network, and the stabilities of all the possible intermolecular interactions in phosphorylated nata de coco membrane with water (NDCF-(H2O)n, n = 1-5). Analysis of natural bond orbital (NBO) was performed to measure the relative strength of the hydrogen bonding interactions, charge transfer, particularly the interactions of n-σ * O-H and to take into account the effect on the stabilities of the molecular structure. All calculation were performed using density functional theory (DFT) method, at B3LYP functional level of theory and 6-311 G** basis set. The charge transfer between the lone pair of a proton acceptor to the anti-bonding orbital of the proton donor provides the substantial to the stabilization of the hydrogen bonds. Interaction between NDCF and (H2O)5 was strongest with the stabilization energy of 37.73 kcal/mol, that indicate the ease of donating lone pair electrons. The contributions of each hydrogen bond to the stability of the complex have been analyzed.

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