• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1539-1542
• /
• 2009

Using one-range addition theorems for Slater type orbitals (STOs) and Coulomb-Yukawa like correlated interaction potentials (CIPs) introduced by the author, the series expansion formulae are derived for the multicenter multielectron integrals. The expansion coefficients occurring in these relations are presented through the overlap integrals of two STOs. The convergence of series expansion relations is tested by calculating concrete cases. The accuracy of the results is quite high for quantum number, screening constants and location of orbitals. The final results are especially useful in the calculation of multielectron properties for atoms and molecules when Hartree-Fock-Roothaan (HFR) and explicitly correlated methods are employed.

• Bulletin of the Korean Chemical Society
• /
• v.4 no.2
• /
• pp.87-91
• /
• 1983

Molecular dynamic method has been applied to a single polymer chain immersed in a solvent. The interactions for the pairs, of two solvent molecules (SS), of a chain element and a solvent molecules (CS), and of two non-neighbor chain elements (CC) are given by the Lennard-Jones potential, and the interaction between two bonded chain elements is given by a harmonic potential. We changed the CS interaction parameter ${\varepsilon}_{CS}$ to 0.5, 1.0 and 2.0 times of the SS interaction ${\varepsilon}_{SS}$. We calculated the pair correlation functions for the SS, CS, and CC pairs, end-to-end distance and radius of gyration with the varying ${\varepsilon}_{CS}$ parameters. The results showed that a phase separation occurs between the polymer and solvent in the 0.5 system where ${\varepsilon}_{CS}$ = 0.5 {\varepsilon}_{SS}$. The autocorrelation functions for end-to-end distance and radius of gyration were also calculated.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.138-143
• /
• 1991

Laser Raman spectroscopy has been used to study the interaction of $MoO_3$ with $TiO_2$. The bulk molybdenum oxide appeared to spread on the surface of titania under the submonolayer coverage. The surface polymolybdate was observed to be very stable with respect to the repeated treatment of reduction and subsequent calcination. Owing to the interaction of molybdate and titania, the phase transformation of $TiO_2$ seemed to be strongly retarded. The additives such as Co and Ni reacted readily with $MoO_3$ to form the corresponding molybdate salts. Nevertheless, the polymolybdate species appeared to be more stable on the titania surface than the molybdate salts.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.7
• /
• pp.732-738
• /
• 2001

The cross second-derivative of the activation energy,${\theta}$G${\neq}$ , with respect to the two component thermodynamic barriers, ${\theta}$G˚X and ${\theta}$G$^{\circ}C$Y, can be given in terms of a cross-interaction constant (CIC), $\betaXY(\rhoXY)$, and also in terms of the intrinsic barrier,${\theta}$G${\neq}$ , with a simple relationship between the two: $\betaXY$ = $-1}(6${\theta}$G${\neq}$).$ This equation shows that the distance between the two reactants in the adduct (TS, intermediate, or product) is inversely related to the intrinsic barrier. An important corollary is that the Ritchie N+ equation holds (for which $\betaXY$ = 0) for the reactions with high intrinsic barrier. Various experimental and theoretical examples are presented to show the validity of the relationship, and the mechanistic implications are discussed.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.9
• /
• pp.748-751
• /
• 1994

Poly(ethylene oxide) (PEO) in aqueous solutions has a hydrophobic character which can induce the hydrophobic interaction between its nonpolar parts. The hydrophobic properties of aqueous PEO solutions are studied by the viscometry in terms of the water structure-making and -breaking capabilities of added solutes of ureas. The results show that the contracted conformation of PEO of low molecular weight, namely poly(ethylene glycol) (PEG), does not result from the hydrophobic interaction between the nonpolar parts of PEO but it can participate in a hydrophobic interaction between the nonpolar parts of PEO and added ureas solutes with nonpolar groups, which can induce a large hydrodynamic volume and increase the viscosity. On the other hand, the PEO of large molecular weight seems to behave like any other water soluble polymers with nonpolar parts and its conformation in aqueous solutions is well explained in terms of water structure perturbing capabilities of added ureas.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.8
• /
• pp.841-850
• /
• 1997

A simple molecular theory of mixtures is formulated based on the nonrandom two-fluid lattice-hole theory of fluids. The model is applicable to mixtures over a density range from zero to liquid density. Pure fluids can be completely characterized with only two molecular parameters and an additional binary interaction energy is required for a binary mixture. The thermodynamic properties of ternary and higher order mixtures are completely defined in terms of the pure fluid parameters and the binary interaction energies. The Quantitative prediction of vapor-liquid, and solid-vapor equilibria of various mixtures are demonstrated. The model is useful, in particular, for mixtures whose molecules differ greatly in size. For real mixtures, satisfactory agreements are resulted from experiment. Also, the equation of state (EOS) is characterized well, even the liquid-liquid equilibria behaviors of organic mixtures and polymer solutions with a temperature-dependent binary interaction energy parameter.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.9
• /
• pp.989-993
• /
• 2001

The carbonyl stretching vibration, νC=O of 2-cyclohexene-1-one, is in Fermi resonance with a combination tone. The amount of Fermi resonance interaction between these two modes is dependent upon the amount of solute/solvent interaction due to hyd rogen bonding between the carbonyl oxygen and the solvent proton. The corrected νC=O frequency of 2-cyclohexene-1-one occurs at a lower frequency than the observed νC=O mode of cyclohexanone, possibly caused by expanded conjugation effects. The carbonyl stretching modes of cyclic ketones were also affected by interaction with the ROH/CCl4 mixed solvent system.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.9
• /
• pp.1010-1013
• /
• 1997

Nucleophilic substitution reactions of (Z)-phenylethyl (X)-benzenesulfonates with (Y)-pyridines were investigated in acetonitrile at 60 ℃ under respective pressures. The magnitudes of the Hammett reaction constants, ρX, ρY and ρZ indicate that a stronger nucleophile leads to a greater degree of bond formation of C-N and a better leaving group is accompanied by a less degree of bond breaking. The magnitude of correlation interaction term, ρij can be used to determine the structure of the transition state (TS) for the SN reaction. As the pressure is increased, the Hammett reaction constants, ρX and |ρY|, are decreased, but correlation interaction coefficient, ρXZ and |ρYZ|, are increased. The results indicate that the reaction of (Z)-phenylethyl (X)-benzenesulfonates with (Y)-pyridines probably moves from a dissociative SN2 to early-type concerted SN2 mechanism by increasing pressure. This result shows that the correlation interaction term ρij can be useful tool to determine the structure of TS, and also the sign of the product ρXZ·ρYZ can be predict the movement of the TS.

• Bulletin of the Korean Chemical Society
• /
• v.21 no.4
• /
• pp.412-418
• /
• 2000

Association of cytochrome c with anionic membranes involved both electrostatic and hydrophobic interactions and their relative contributions depended on the physical state of the membrane and the redox state of cyto-chromec.Hydrophobic interaction was favored by the membranes in gel phase, by the membranes with a large curvature, and by the membranes with a high surface charge density. Ferrocytochrome c was less dissociable by NaCl than ferricytochrome c suggesting that a lower protein stability is beneficial for hydrophobic interac-tion.Hydrophobic interaction induced larger structural perturbations on cytochrome c as monitored by the loss of the Fe-Met bond and by the increase in the distance between heme and Trp-59. When bound to anionic mem-branes,spin-labeled cytochrome c showed an electron paramagnetic resonance spectrum with two or more components, providing a direct evidence for multiple conformations of bound cytochrome c.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.10
• /
• pp.1099-1105
• /
• 1998

A series of (diamine)isopropylidenmalonatoplatinum(Ⅱ) complexes and the oxidation products, (diamine)Pt (OOC)2C=C(CH3)2(X)2, (diamine=ethylenediamine(en), 1,2-diaminopropan(dap), N-methylethylenediamine(men); X=OH, OCOCH3, OCOCF3), have been prepared, and their interaction with guanosine-5'-monophosphate (5'-GMP) have been examined by means of 1H NMR spectroscopy. The present platinum(Ⅱ) complexes have shown to interact with 5'-GMP through N7 coordination in two concecutive steps in a similar way as with cisplatin, but no interaction between the present platinum(Ⅳ) complexes and 5'-GMP was observed. However, in the presence of ascorbic acid, the platinum(Ⅳ) complexes have been found to interact with 5'-GMP with the reaction rate depending on their reduction rate.