Electronic Structure, Molecular Electrostatic Potentials, Vibrational Spectra in Substituted Calix[<i>n</i>]arenes (<i>n</i>= 4, 5) from Density Functional Theory

Khedkar, Jayshree K.; Pinjari, Rahul V.; Gejji, Shridhar P.

doi:10.1021/jp205441s

Cited by 19 publications

(11 citation statements)

References 83 publications

(126 reference statements)

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“…Electrostatic potential (ESP) surfaces of the absorbates molecules and ESP surfaces of the POSS cages are shown in the ESI. † Natural bond orbital (NBO) analysis [45][46][47] was performed and the charges for the molecules are provided in ESI † (Table S3). All diatomic molecule atoms are negatively charged when they are at the center of T 10 indicating that the T 10 donates electron density to the absorbates; this is with the exception of the carbon of CO, where the oxygen is more electronegative than the carbon.…”

Section: Pccp Papermentioning

confidence: 99%

The insertion of gas molecules into polyhedral oligomeric silsesquioxane (POSS) cages: understanding the energy of insertion using quantum chemical calculations

Skelton

Fried

2013

Phys. Chem. Chem. Phys.

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Density functional theory (DFT) calculations using the B3LYP and ωB97XD functionals and Møller-Plesset (MP2) calculations have been used to determine the energy of insertion of seven molecules (CO2, N2, O2, CO, CH4, He and H2O) into two sizes of polyhedral oligomeric silsesquioxane (POSS) cages, T10 and T12. Geometry optimization results of each molecule inserted into the center of the POSS cage and transition-energy searches of the molecules in the largest face of both T10 and T12 (identified as the Si5 face) are discussed. The main factors that affect the energy of a molecule in a particular POSS cage are the size (number of atoms) and shape of the POSS cage and the strength of dispersion and electrostatic interactions. The largest of the molecules, CO2 and CH4, have the largest interaction energies within the center and the face of the T10 and T12 cages. Interaction energies for the diatomic molecules increase in the order H2 < O2 < N2 ∼ CO and differences between interaction energies can be attributed, in part, to differences in electron transfer between the cage and molecule. Electrostatic interactions also play a significant role in determining the interaction energy. For example, H2 and He are only slightly charged when inside the POSS cages, providing little repulsive or attractive interactions, while polar CO provides significant repulsive interaction. In the case of water, the interaction energies are low because of hydrogen bonding between the water hydrogen atoms and the POSS oxygen atoms. The interaction energies of the absorbates at the center of T12 are typically smaller than for T10 due to the larger cavity size of T12. The Si5 face has the same basic structure for both T10 and T12 cages and, consequently, the interaction energies of the absorbate molecules at the face are similar. Interaction energies obtained using MP2 calculations are lower than those obtained from DFT calculations depending on the choice of the functional. For example, use of the ωB97XD functional that treats dispersion interactions more completely than the B3LYP functional, produces values closer to the MP2 values. These results, therefore, suggest that dispersion is important in the interaction between small molecules and POSS cages.

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Section: Pccp Papermentioning

confidence: 99%

The insertion of gas molecules into polyhedral oligomeric silsesquioxane (POSS) cages: understanding the energy of insertion using quantum chemical calculations

Skelton

Fried

2013

Phys. Chem. Chem. Phys.

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“…56 The topography of the scalar field such as molecular electrostatic potential (MESP) has been utilized to estimate the size and shape of calixarene derivatives. 57 Moreover, the cooperativity effects accompanying the underlying molecular interactions can be brought about through MESP. 58 To understand the driving force responsible for encapsulation of small gaseous molecules within calix [4]arene, molecular dynamics simulations were carried out by Deakyne et al 59 Despite the aforementioned studies, almost no endeavor, within DFT, appears to have been made toward the description of partial thia-substituted calix [4]arenes.…”

Section: ■ Introductionmentioning

confidence: 99%

Cooperative Hydrogen Bonding, Molecular Electrostatic Potentials, and Spectral Characteristics of Partial Thia-Substituted Calix[4]arene Macrocycles

Lande

Gejji

2016

J. Phys. Chem. A

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Structure and spectral characteristics of the 2,14-dithiacalix[4]arene and its homooxa derivatives are obtained employing the dispersion-corrected ωB97X-D-based density functional theory. The conformational behavior of these receptors is governed by the nature and number of substituents at the bridging positions. The partial thia-substituted calix[4]arene scaffolds reveal the electron-rich regions reside near heteroatoms which emerge with deeper minima in molecular electrostatic potential topography. Underlying cooperativity of intramolecular hydrogen bonding manifests in characteristic OH vibrations of their infrared spectra. Moreover, the (1)H NMR reveals that hydrogen-bonded protons are deshielded, unlike those from tertiary butyl substituents. These inferences are in agreement with the experimental data.

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“…The calix [4]arene (C4A) has four conformers [25,[29][30][31][32]. Previous studies have demonstrated that the cone conformer is the most stable [29,32].…”

Section: Introductionmentioning

confidence: 99%

“…Four intramolecular hydrogen bonds O-H· · · O are formed in the cone conformers of C4A, which allows C4A to act as host for a wide range of guests. Thus, C4A is an excellent model in which to study intramolecular hydrogen bonding in the excited state [32][33][34][35]. However, little information is available on electronic excited-state intramolecular hydrogen bonding due to the extremely short timescales involved.…”

Section: Introductionmentioning

confidence: 99%

Role of intramolecular hydrogen bonding in the excited-state intramolecular double proton transfer (ESIDPT) of calix[4]arene: A TDDFT study

Wang

Hao

2016

Open Physics

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Abstract:The time-dependent density functional theory (TDDFT) method was performed to investigate the excitedstate intramolecular double proton transfer (ESIDPT) reaction of calix [4]arene (C4A) and the role of the intramolecular hydrogen bonds in the ESIDPT process. The geometries of C4A in the ground state and excited states (S 1 , S 2 and T 1 ) were optimized. Four intramolecular hydrogen bonds formed in the C4A are strengthened or weakened in the S 2 and T 1 states compared to those in the ground state. Interestingly, upon excitation to the S 1 state of C4A, two protons H1 and H2 transfer along the two intramolecular hydrogen bonds O1-H1· · · O2 and O2-H2· · · O3, while the other two protons do not transfer. The ESIDPT reaction breaks the primary symmetry of C4A in the ground state. The potential energy curves of proton transfer demonstrate that the ESIDPT process follows the stepwise mechanism but not the concerted mechanism. Findings indicate that intramolecular hydrogen bonding is critical to the ESIDPT reactions in intramolecular hydrogen-bonded systems.

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Electronic Structure, Molecular Electrostatic Potentials, Vibrational Spectra in Substituted Calix[n]arenes (n= 4, 5) from Density Functional Theory

Cited by 19 publications

References 83 publications

The insertion of gas molecules into polyhedral oligomeric silsesquioxane (POSS) cages: understanding the energy of insertion using quantum chemical calculations

The insertion of gas molecules into polyhedral oligomeric silsesquioxane (POSS) cages: understanding the energy of insertion using quantum chemical calculations

Cooperative Hydrogen Bonding, Molecular Electrostatic Potentials, and Spectral Characteristics of Partial Thia-Substituted Calix[4]arene Macrocycles

Role of intramolecular hydrogen bonding in the excited-state intramolecular double proton transfer (ESIDPT) of calix[4]arene: A TDDFT study

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