• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3321-3330
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• 2012

The complexation characteristics of mixed [2 + 2'] calix[4]aryl derivatives (3 and 4) with alkali metal cations were investigated by the mPW1PW91 (hybrid HF-DF) calculation method. The total electronic and Gibbs free energies of the various complexes (cone, partial-cone, 1,2-alternate, and 1,3-alternate) of sodium and potassium cations with 3 and 4 were analyzed and compared. The structures of the endo- or exo-complexes of the alkali metal cation with the host 3 were optimized using the mPW1PW91/6-31G(d) method, followed by mPW1PW91/6-311+G(d) calculations. The structures of the endo- or exo-complexes of the alkali metal cation with the host 4 were optimized using the mPW1PW91/6-31G(d,p) method. The mPW1PW91 calculated relative energies of the various conformations of the free hosts (3 and 4) suggest that the cone conformers of 3 and 4 are the most stable. The mPW1PW91calculations also suggest that the complexation efficiencies of the sodium ion with hosts 3 and 4 are about 24 and 27 kcal/mol better than those of the potassium ion, respectively. These trends are in good agreement with the experimental results. The exo-complexation efficiencies of the sodium ion toward the conformers of hosts 3 and 4 are roughly 14 and 17 kcal/mol better than those for the endo-$Na^+$-complexes of 3 and 4, respectively. The exo-complexation of the cone isomer of 3 with cation could be confirmed by the differences of the diagnostic C=O bands in the free host and its complex's IR spectra.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.640-652
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• 2009

We have performed mPW1PW91 calculations to investigate the conformational characteristics and hydrogen bonds of p-tert-butylcalix[4]arene (1), p-tert-butylcalix[5]arene (2), calix[6]arene (3) and p-tertbutylcalix[6]arene (4). The structures of the different conformers of 1-3 were optimized by using mPW1PW91/6-31+G(d,p) method. The relative stability of the four conformers of 1 is in the following order: cone (most stable) > partial-cone > 1,2-alternate > 1,3-alternate. The relative stability of the conformers of 2 is in the following order: cone (most stable) > 1,2-alternate > partial-cone > 1,3-alternate. The relative stability of the various conformers of 3 is in the following order: cone (pinched: most stable) > partial-cone > cone (winged) - 1,2-alternate - 1,2,3-alternate > 1,4-alternate > 1,3-alternate > 1,3,5-alternate. The structures of the various conformers of 4 were optimized by using the mPW1PW91/6-31G(d,p) method followed by single point calculation of mPW1PW91/6-31+G(d,p). The relative stability of the conformers of 4 is in the following order: cone (pinched) > 1,2-alternate > cone (winged) > 1,4-alternate - partial-cone > 1,2,3-alternate > 1,3,5-alternate > 1,3-alternate. The primary factor affecting the relative stabilities of the various conformers of the 1-4 are the number and strength of the intramolecular hydrogen bonds. The hydrogen-bond distances are discussed based on two different calculation methods (B3LYP and mPW1PW91).

• Journal of the Korean Chemical Society
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• v.53 no.5
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• pp.521-529
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• 2009

Molecular structures of the various conformers for the 1,3-dimethoxy-p-tert-butylthiacalix[4] crown-5-ether (3) were optimized by using DFT B3LYP/6 - 31 + G(d,p) and mPW1PW91/6 - 31 + G(d,p) (hybrid HF-DF) calculation methods. We have analyzed the energy differences and structures of eight in/out orientations (cone_oo, cone_oi, pc_oo, pc_io, pc_oi, pc_ii, 13a_oo, 13a_io) of two methoxy groups in three major conformations (cone, partial-cone and 1,3-alternate). The 13a_oo (out-out orientation of the 1,3-alternate conformer) is calculated to be the most stable among eight different conformations of 3, and in accord with the experimental result. The ordering of relative stability resulted from the mPW1PW91/6 - 31 + G(d,p) calculation method is following: 13a_oo > 13a_io$\sim$pc_io$\sim$cone_oo > cone_oi$\sim$pc_oo$\sim$pc_oi > pc_ii.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.100-104
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• 2011

The structures of the conformers for 1,3-di-t-butyl-2,4-dinitro-tetramethoxysulfonylcalix[4]arene (1) and 1,2-di-t-butyl-3,4-dinitro-tetramethoxysulfonylcalix[4]arene (2) were optimized using DFT BLYP and mPW1PW91/6-31G(d,p) (hybrid HF-DF) calculation methods. We have analyzed the total electronic and Gibbs free energies and the differences between the various conformations (cone, partial-cone (PC), 1,2-alternate, and 1,3-alternate) of 1 and 2. For both compounds, the 1,3-alternate (1,3-A) conformers were calculated to be the most stable, which correlate very well with the experimental results. The orderings of the relative stability of 1 and 2 that resulted from the mPW1PW91/6-31G(d,p) calculations are the following: 1: 1,3-A (syn) > PC (syn) > PC (anti) > 1,2-A (anti) > CONE (syn); 2: 1,3-A (anti) > PC (anti) > PC (syn) > 1,2-A (anti) > 1,2-A (syn) > CONE (syn). The BLYP/6-31G(d) calculated IR spectra of the most stable 1,3-A conformers of 1 and 2 are compared.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3247-3251
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• 2010

Molecular structures of the various conformers for the four stereoisomers of tetra-t-butyl-tetra-O-methylsulfinylcalix[4]arene (1) were optimized using DFT BLYP and mPW1PW91/6-31G(d,p) (hybrid HF-DF) calculation methods. We have analyzed the total electronic and Gibbs free energies and normal vibrational frequencies of 16 different structures from four major conformations (cone (CONE), partial cone (PC), 1,2-alternate (1,2-A), 1,3-alternate (1,3-A)) of the four stereoisomers [1(rccc), 1(rcct), 1(rctt), 1(rtct)]. The mPW1PW91/6-31G(d,p) calculations suggested that the $1(rccc)_{CONE}$, $1(rcct)_{PC}$, $1(rctt)_{PC}$, and $1(rtct)_{1,3-A}$ were the most stable conformations of the respective stereoisomers. These outcomes are in accordance with the experimental structures obtained from X-ray crystallography. The electrostatic repulsion between the sulfinyl and methoxy groups is a primary factor for the relative stabilities of the four different conformations. The IR spectra of the most stable conformers [$1(rccc)_{CONE}$, $1(rcct)_{PC}$, $1(rctt)_{PC}$, $1(rtct)_{1,3-A}$] of each stereoisomer were compared to each other.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1323-1328
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• 2014

Molecular structures of the various conformational stereoisomers of 2,8,14,20-cyanophenyl pyrogallol[4]arenes 1 were optimized using the mPW1PW91 (hybrid Hartree-Fock density functional) calculation method. The total electronic and Gibbs free energies and the normal vibrational frequencies of the different structures from three major conformations (CHAIR, TABLE, and 1,2-Alternate) of the four stereoisomers [1(rccc), 1(rcct), 1(rctt), and 1(rtct)] were analyzed. The mPW1PW91/6-31G(d,p) calculations suggested that $1(rcct)_{1,2-A}$, 1(rctt)CHAIR, and $1(rtct)_{CHAIR}$ were the more stable conformations of the respective stereoisomers. Hydrogen bonding is the primary factor for the relative stabilities of the various conformational isomers, and maximizing the ${\pi}-{\pi}$ interaction between the cyanophenyl rings is the secondary factor. The calculated IR spectra of the more stable conformers [$1(rctt)_{CHAIR}$, $1(rcct)_{1,2-A}$, $1(rtct)_{CHAIR}$] were compared with the experimental IR spectrum of $1(rtct)_{CHAIR}$.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1685-1691
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• 2011

The molecular structures of thiacalix[4]biscrown-5 (1) and p-tert-butylthiacalix[4]biscrown-5 (2) and their alkali-metal-ion complexes were optimized using the DFT BLYP/6-31G(d) and mPW1PW91/6-31G(d,p) (hybrid HF-DF) calculations. The total electronic energies, the normal vibrational modes, and the Gibbs free energies of the mono- and di-topic complexes of each host with the sodium and potassium ions were analyzed. The $K^+$-complexes exhibited relatively stronger binding efficiencies than $Na^+$-complexes for both the monoand di-topic complexes of 1 and 2 comparing the efficiencies of the sodium and potassium complexes with an anisole and phenol. The mPW1PW91/6-31G(d,p) calculated distances between the oxygen atoms and the alkali metal ions were reported in the alkali-metal-ion complexes ($1{\cdot}Na^+$, $1{\cdot}2Na^+$, $1{\cdot}K^+$, $1{\cdot}2K^+$, $2{\cdot}Na^+$, $2{\cdot}Na^+$, $2{\cdot}K^+$, $2{\cdot}2K^+$). The BLYP/6-31G(d) calculated IR spectra of the host 1 and its mono-topic alkali-metal-ion complexes are compared.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2175-2179
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• 2010

Quantum mechanical properties of unsymmetrical and unfunctionalized trans-stilbene derivatives 1-3, which had been prepared by solid-phase parallel syntheses, were characterized using mPW1PW91/6-311G(d,p) (hybrid HF-DF) calculations. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of sixteen different structures from three different groups were analyzed. The energy differences between the HOMOs and LUMOs of the various unsymmetrical trans-stilbenes are in accord with the maximum absorption peaks of the experimental UV spectra of 1-3. The calculated normal vibrational modes of 21 were comparable with its experimental IR spectrum. The $\pi$-conjugation in the para-connected biphenyl group of 2 is better than the one in the metaconnected biphenyl group on the shorter side of 3.

• Journal of Preventive Medicine and Public Health
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• v.54 no.5
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• pp.317-329
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• 2021

Objectives: The aim of this study was to identify the association between cohabitation status and sleep quality in family members of people with dementia (PwDs). Methods: Data of 190 365 participants aged ≥19 years from the 2018 Korea Community Health Survey were analyzed. Participants were categorized according to their cohabitation status with PwDs. Multiple logistic regression and ordinal logistic regression analyses were performed to evaluate the relationship between the cohabitation status of PwDs' relatives and sleep quality measured using the Pittsburgh Sleep Quality Index (PSQI) and PSQI subscales. Results: Compared to participants without PwDs in their families, both cohabitation and non-cohabitation with PwDs were associated with poor sleep quality (cohabitation, male: odds ratio [OR],1.28; 95% confidence interval [CI], 1.08 to 1.52; female: OR, 1.40; 95% CI, 1.20 to 1.64; non-cohabitation, male: OR, 1.14; 95% CI, 1.05 to 1.24; female: OR, 1.23; 95% CI, 1.14 to 1.33). In a subgroup analysis, non-cohabiting family members showed the highest odds of experiencing poor sleep quality when the PwD lived alone (male: OR, 1.48; 95% CI, 1.14 to 1.91; female: OR, 1.58; 95% CI, 1.24 to 2.01). Cohabiting male and female participants had higher odds of poor subjective sleep quality and use of sleeping medications than non-cohabiting male and female participants, respectively. Conclusions: The residence of PwDs and cohabitation status may contribute to poor sleep quality among PwDs' family members. The circumstances faced by cohabiting and non-cohabiting family members should be considered when evaluating sleep quality in family members of PwDs, and appropriate interventions may be needed to improve sleep quality in both cohabiting and non-cohabiting family members.

• Korean Journal of Microbiology
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• v.35 no.3
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• pp.237-241
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• 1999

Phenolic resin wastewater contained 41,000 mglI phenol, 2,800 mg/l fonualdehyde and various chlorinated phenolic compounds. Candida tropicalis PW-51 isolated [rom the natural enVlfooment was able to degrade 1,000 mg/l phenol in the presence of 100 mglI formaldehyde, but it took much time to degrade phenol with the increase of formaldehyde in phenolic resin wastewater. %en the phenolic resin wastewater was diluted to 1/40, the initial concentration of phenolic compounds (phenols) was 882 mglI and degraded to 81 mglI by C tfVpicalis PW-51 in batch culture. In a continuous biological treatment, the phenolic resin wastewater was diluted to 40 (745 mglI), 20 (1,356 mglI), or 10 (2,875 mglI) times. The removal efficiency of phenols in 1/40- and lI20-diluted phenolic resin wastewater was about 92%, but the phenols in 1!1O-diluted wastewater were not degraded. The remained phenols in wastewater were absorbed by a mixture of activated carbon and rice bran (1:1, v:v) in the process of absorption which was connected to the biological treatment. The total removal efficiency of phenols in 1!40~ and l/20-diluted phenolic resin wastewater was 99.9%.