A series of new ferrocene derivatives containing cyclohexylphosphines have been prepared from the reactions of lithioferrocenes with corresponding chlorodicyclohexylphosphines. 1-diphenylphosphino-1'-dicyclohexylphosphinoferro cene has been prepared from [1]-ferrocenophane via a ring cleavage reaction. Chiral ferrocenylaminophosphines incorporating cyclohexyl-and cyclopentadienylphosphines have also been prepared from the chiral template 2-N,N-dimethylaminoethylferrocene (FA) via stereoselective lithiation followed by phosphination with corresponding $R_2PCl$(R= $C_6H_{11}$, $C_5H_5$). The synthesis of cyclopentadienylphosphine derivative of (R)-FA (6b) led to the formation of a mixture of four diastereomers due to the presence of three chiral sources in the final product in addition to the fluxional behavior of the $η^1$-$C_5H_5$ group attached to the phosphorus. All these new compounds have been characterized by analytical and spectroscopic techniques.

To improve the lifetime and output power in a sealed-off $CO_2$ laser, a series of Nd$_{1-x}$Sr$_x$CoO$_3$(x = 0.0, 0.25, 0.40, 0.50, 0.60, 0.75) perovskite-type compounds has been synthesized and used for a cathode material. Using a typical method samples were sintered at 1150$^{\circ}$C and their structures were determined as a cubic form by means of XRD analysis. The degrees of $CO_2$ dissociation were measured by PAS (photoacoustic spectroscopy) with the lapse of time. In the case of $Nd_{0.4}$Sr$_{0.6}$$CoO_3$, which showed the highest catalytic cathode effect, only 7% of the initial $CO_2$ concentration were dissociated at 30 torr of gas mixture and 5 mA of discharge current. The more the gas pressure decreased and the discharge current increased, the more the degree of dissociation occurred. The ability of catalytic cathode to regenerate CO$_2$ in the laser cavity lies in order for x, 0.60 > 0.50 > 0.40 > 0.75 > 0.25 ${\gg}$ 0.0. Except for the case of x = 0.0 the amounts of $CO_2$ dissociation were found to be within 7-15% of the initial $CO_2$ concentration.

The temperature dependence of C-13 chemical shifts are observed for the cyclooctanone arylhydrazones. The temperature-dependent chemical shifts for these derivatives are explained by postualating the existence of two equilibrating structures. In addition, the assignment between the $^{13}C$ signals of methylene carbon pairs can be done by application of the ${gamma}$ -substituent effect.

Rate constants of methanolyses of para-Z-substituted benzenesulfonyl chlorides have been determined in various isodielectric solvent mixtures. A third-order kinetic behavior has been observed in the methanolysis of p-nitrobenzenesulfonyl chloride in methanol-nitromethane mixture from the correlation figure of logarithms of rate constants were plotted against Y-values based on solvolyses of 1-adamantyl tosylate. $S_N1$-$S_N2$ mixing mechanisms are favored by neutral or weak electron-donating and weak electron-withdrawing substituents of p-Z-substituted benzenesulfonyl chlorides in methanol-nitrobenzene mixture. While the methanolyses of para-Z-substituted benzenesulfonyl chlorides in methanol-ethylene glycol solvent mixture are appropriate for $S_N2$ mechanism from the mechanistic criterion by means of m-values.

Chromium oxide/zirconia catalysts were prepared by dry impregnation of powdered $Zr(OH)_4$ with ($NH_4$)$_2$CrO$_4$aqueous solution. The characterization of prepared catalysts was performed using FTIR, XPS, XRD and DTA methods, and by the measurement of surface area. The addition of chromium oxide to zirconia shifted the transitions of $ZrO_2$ from amorphous to tetragonal phase and from tetragonal to monoclinic phase to higher temperature due to the strong interaction between chromium oxide and zirconia, and the specific surface area of catalysts increased in proportion to the chromium oxide content. Since the $ZrO_2$ stabilizes supported chromium oxide, chromium oxide was well dispersed on the surface of zirconia, and ${\alpha}$-$Cr_2O_3$ was observed only at the calcination temperature above 1173 K. Upon the addition of only small amount of chromium oxide (1 wt% Cr) to $ZrO_2$, both the acidity and acid strength of catalyst increased remarkably, showing the presence of two kinds of acid sites on the surface of $CrO_x$/$ZrO_4$-Bronsted and Lewis.

The solvent-dependent photophysical properties of 2-biphenylcarboxylic acid (2BPCA) and 4-biphenylcarboxylic acid(4BPCA), which have a pre-twisted conformation in the ground state, have been investigated. The fluorescence spectra of 4BPCA show vibrational structure with a non-mirror image to the absorption spectra in nonpolar solvent while those of 2BPCA show no structure even in nonpolar solvents. As the solvent polarity increases, the fluorescence spectra become diffuse and broad with a strong red shift resulting in the large Stokes shift. The large fluorescence Stokes shift of BPCA's in polar solvent is also partially due to an intramolecular charge transfer (ICT) interaction in the excited state, as demonstrated by the large dipole moment in the excited state (7.6-10.6 D). The fluorescence decay behaviors of BPCA's (decay-times and their pre-exponential factors) also depend on solvent polarity in agreement with the solvent-dependent properties of the steady-state fluorecence. The data have been discussed in terms of change in the excited-state potential energy surface with respect to change of the dihedral angle of biphenyl moiety.

The analytical performance of glow discharge mass spectrometer (GD-MS), using a flat type ion source is discussed. The efficiency of ion extraction was maximized at the distance between anode and cathode of 6 mm. At the operation condition of 4 mA, -1000 volt, and 1 mbar for the source, the optimum voltages for sampler and skimmer were40 volt and -280 volt, respectively. The intensities of Cu, Zn, and Mn were increased as a function of square root of current approximately. Korea standard reference materials (KSRM) were tested for an application study. The detection limits of most elements were obtained in the range of several ppm at the optimized operating condition. The peaks of aluminum and chromium were interfered by those of residual gases. The depth profile of nickel coated copper specimens (3, 5, 10 ${\mu}m$ thickness) were obtained by plotting time versus intensities of Ni and Cr after checking the thickness of nickel coated using a scanning electron microscope (SEM). At this moment, the sputtering rate of 0.2 ${\mu}m/min$ at the optimum operating condition was determined from the slope of the plot of time to the coating thickness. The roughness spectra of specimen's crater after 16 min, discharge were obtained using a Talysuf5m-120 roughness tester as well.

This article deals with the synthesis and characterization of poly [N-(propargyloxy)phthalimide][poly (POPI)]. The polymerization of POPI was carried out by various transition metal catalysts. $MoCl_5$-based catalysts were found to be more effective than $WCl_6$-based catalysts. However, the polymer yield was relatively low (maximum 35%). The polymerization of POPI by $PdCl_2$ gave poly (POPI) in fair yields in DMF and pyridine. The resulting poly (POPI)s were mostly insoluble in organic solvents. The infrared spectrum of poly (POPI) showed no peak at 2135 $cm^{-1}$ due to acetylenic $C{\equiv}C$ stretching frequency. Instead, the carbon-carbon double bond stretching frequency was observed at 1600-1650 $cm^{-1}$. The TGA thermogram showed that the present poly (POPI) is thermally stable up to $160^{\circ}C.$.

The dihydrido iridium(Ⅲ) complex [$Ir(PPh_3)_2H_2(ac)_2$]$BF_4$ (ac=acetone) reacts with 2-phenylpyridine and 7,8-benzoquinoline to yield the C-H activated complexes [$Ir(PPh_3)_2$H(ac)(L)]$BF_4$ (L= phenylpyridine; 7,8-benzoquioline). The dihydrido iridium(Ⅲ) complex [$Ir(PPh_3)_2H_2(ac)_2$]$BF_4$ also reacts with triaklysilane via an oxidative addition reaction to yield the trihydrido iridium complexes [$Ir(PPh_3)_2H_3SiR_3$]$BF_4$ (R =Et and Ph). The structual configuration was studied by conventional spectroscopy.

Second-order rate constants have been determined spectrophotometrically for nucleophilic substitution reactions of p-nitrophenyl benzoate with various anionic nucleophiles including 6 ${\alpha}$ -effect nucleophiles. The logarithmic second-order rate constants for the aryloxides give a good Bronsted correlation with the respective basicity while the ones for p-chlorothiophenoxide and hydroxide exhibit significantly positive and negative deviations, respectivity, from the Bronsted linear line. The deviations are attributed to a solvation effect rather than a change in the reaction mechanism. The ${\alpha}$-effect nucleophiles except highly basic ones demonstrate significantly higher nucleophilicity (the ${\alpha}$ -effect) than would be predicted from the respective basicity. The effect of solvation and polarizability appears to be important for the ${\alpha}$-effect as well as for the reaction rate.

Preferential solvation (PS) phenomena of solutes based on solvent polarity, $E_T$ and AN, were studied by UV/vis. and NMR spectra in MeOH binary mixtures. According to the extent of solvent-solvent interaction, different solvation phenomena were found. PS concept was applied to explain the reactivity of tert-butyl halides solvolysis. The findings of solvation phenomena have been related to the rate of solvolysis and PS suggested as a reason for the solvent dependence of the rates of reaction. Moreover, we found that the results of principal components analysis using six parameters are in good accordance with the results of PS phenomena in mixed methanol systems.

Second-order rate constants have been measured spectrophotometrically for the reactions of substituted phenyl acetates with butane-2,3-dione monoximate and p-chlorophenoxide anions in MeCN-H$_2$O mixtures of varying compositions. The reaction rate, unexpectedly, decreased remarkably upon initial additions of MeCN to H$_2$O up to 30-40 mole ${\%}$ MeCN, and followed by a gradual increase upon further additions of MeCN. The change in solvent composition also influenced the magnitude of the ${\alpha}$-effect, i.e., the ${\alpha}$-effect increased as the mole ${\%}$ MeCN increased. The solvent dependent ${\alpha}$-effect for the present system appears to indicate that the differential solvation between the ${\alpha}$-effect nucleophile and the corresponding normal nucleophile is not solely responsible but the difference in the transition-state stabilization is also responsible for the ${\alpha}$ -effect in organic solvent-rich region.

The critical micelle concentration (CMC) values of cetylpyridinium chloride (CPC) in some alcohol-aqueous solutions were determined by UV-Vis spectroscopy at 25$25^{\circ}C$. The CMC of CPC was increased with the addition of methanol and ethanol, while with the addition of propanol it was decreased because of the solubilization of propanol into the micelle of CPC. The ratio (${\beta}$) of the number of counterions to that of surfactant ions associated into micelles in alcohol (methanol, ethanol and propanol) aqueous solutions was measured by using the Shinoda $equation^{17}$. The ratio of counterion binding to the CPC micelles in methanol-and ethanol-water mixtures was larger than in pure water, while the ratio in propanol-water mixture might be much decreased.

Absorption and fluorescence spectra are reported for four different 1 : 3 $Dy^{3+}$ : ligand systems in aqueous solution under mild alkaline pH conditions. The ligands included in this study are oxidiacetate, dipicolinate, iminodiacetate and methyliminodiacetate. The oscillator strengths for the 4f→4f multiplet-to-multiplet transitions are empirically determined from the absorption spectra and the intensity parameters ${\Omega}_{\lambda}$}(${\lambda}$ = 2, 4, 6) for the systems are also obtained by applying the Judd-Ofelt theorem to the observed oscillator strengths. The values of the intensity parameters for the systems are compared and discussed in terms of ligand structural properties to investigate how the intensity parameters can response to the minor changes in the ligand environment. In addition, the relative oscillator strengths for fluorescence are evaluated and compared to the results obtained from absorption spectra.

Photolysis of 1-phenyl-1,3,5-hexatriynes in deaerated tetrahydrofuran gave photoreduction and photoaddition products, while photolysis of 1-phenyl-1,3,5-hexatriynes in deaerated alcoholic solvents (methanol, i-propanol) yielded dark red products, probably oligomers or decomposition products of reactants, as exclusive major products. A plausible mechanism for the reaction is proposed.

The pressure-jump relaxation method has been used to determine the rate constants for the formation and dissociation of maganese(Ⅱ), cobalt(Ⅱ), and nickel(Ⅱ) with some dicarboxylates in aqueous solution at zero ionic strength. The carboxylate ligands used are 3-nitrophthalate, 4-nitrophthalate, and phenylmalonate. The activation parameters have alse been obtained from the temperature dependence of the rate constants. A dissociative interchange mechanism with a chelate ring closure step as rate determining is employed to interpret the kinetic data of manganese(Ⅱ) and cobalt(Ⅱ) complexes. The rates of formation of nickel(Ⅱ) complexes are controlled by both the solvent exchange step and the chelate ring closure step.

The superconducting $YBa_2Cu_4O_8$ was synthesized in oxygen condition at 1 atm. The starting material with 1 : 2 : 4 composition was obtained by pyrolysis of EDTA complex, which was converted to 1-2-3 phase during densification, followed by the 1-2-4 phase recovery at $810^{\circ}C$ . The phase presents were identified by XRD, TG, DTA and AC magnetic susceptibility. Our data indicated that considerable amounts of 1-2-4 phase formed but with the 1 : 2 : 3 phase or possibly 2-4-7 as visible. As the P($O_2$) increased with temperature, impurity peak, CuO ($2{\Theta}$ = 38.8), gradually decrease, and we conclude that the 1-2-4 phase is predominant bulk superconductor under the high oxygen pressure.

We consider the problem of a random walker on a one-dimensional lattice (N sites) confronting a centrally-located deep trap (trapping probability, T=1) and N-1 adjacent sites at each of which there is a nonzero probability s(0 < s < 1) of the walker being trapped. Exact analytic expressions for < n > and the average number of steps required for trapping for arbitrary s are obtained for two types of finite boundary conditions (confining and reflecting) and for the infinite periodic chain. For the latter case of boundary condition, Montroll's exact result is recovered when s is set to zero.

A systematic study of the partial reduction of carboxylic acids and their derivatives to the corresponding aldehydes with lithium tris(dialkylamino)aluminum hydrides under practical conditions has been carried out. The diethylaminosubstituted derivative of lithium aluminum hydride, lithium tris(diethylamino)aluminum hydride (LTDEA), shows quite general applicability in the conversion of carboxylic acids, carboxylic esters, and primary carboxamides to the corresponding aldehydes. Lithium tripiperidinoaluminum hydride (LTPDA) also appears to be a reagent of choice for such partial transformation of primary carboxamides. In additioin, both LTDEA and LTPDA reduce tertiary carboxyamides to aldehydes in high yields. Finally, lithium tris(dihexylamino)aluminum hydride (LTDHA) is capable of achieving the chemoselective reduction of aromatic nitriles to aldehydes in the presence of aliphatic nitriles under practical conditions.

Irradiation of N-t-butyl-N-chloro-3-phenylpropanesulfonamide (1a) in benzene at $20^{\circ}C$ using 450 W high pressure mercury arc lamp in the presence of oxygen affored N-t-butyl-3-phenylpropanesulfonamide (2), N-t-butyl-3-chloro-3-phenylpropanesulfonamide (3), and N-t-butyl-3-oxo-3-phenylpropanesulfonamide (4). Similarly, N-t-butyl-4- (5), N-t-butyl-4-chloro-4- (6), and N-t-butyl-4-phenylbutanesulfonamides (7) were obtained from N-t-butyl-N-chloro-4-phenylbutanesulfonamide (1b). However, irradiation of N-t-butyl-N-chloro-5-phenylpentanesulfonamide (1c) under the same conditions gave complex mixtures. These results indicate that sulfonamidyl radical generated from each of 1a and 1b can abstract intramolecularly a hydrogen atom from the benzylic position only by forming six and seven-membered transition states, respectively.

The electrochemistry of benzidine and hydrazobenzene was studied in water-acetonitrile mixed solutions at various pHs and the results are reported. The cyclic voltammetric peak for the oxidation of benzidine shows a pH dependency of -62 mV/pH in the pH range of 0-3.5, no pH dependency between pH values of 3.5 and about 10.5, and of about -50 mV/pH between pH=10.50 and 14.0, indicating that oxidation mechanisms differ depending on the pH of the medium. However, the CV peak for the hydrazobenzene oxidation is shown to be independent of pH of the medium, suggesting that the proton is not involved in the rate limiting step of the electrochemical oxidation of hydrazobenzene to azobenzene. Results of in situ spectroelectrochemical experiments indicate that the oxidation products obtained during the oxidation of benzidine and hydrazobenzene depend on the result of dynamic equilibria taking place at various pHs.

Three photocyclodimers of 5,7-dimethoxycoumarin (DMC) were isolated and characterized from the photolysis of DMC in acetonitrile. The configuration of the dimers was found to be anti head-to-head, syn head-to-head and syn head-to-tail, respectively. The number and the ratio of the products are solvent dependent. The anti head-to-head dimer is favored in nonpolar solvents and the preference decreases as the solvent polarity increases giving almost 100${\%}$ syn dimers and less than 1${\%}$ anti dimer from methanol solution. The overall yields of dimers also increase with the solvent polarity. From sensitization and quenching experiments, anti dimer was found to be formed via excited singlet state while syn dimers were formed via both excited singlet and triplet states.

Methods for the selective functionalization of calix[4]arene at the upper rim are described. The diametrically substituted calix[4]arene dimethyl ether 2, obtained from the treatment of calix[4]arene 1 with methyl iodide in the presence of $K_2CO_3$, is converted to the two isomeric p-diacetylcalix[4]arene dimethyl ether 3 and 6 by direct substitution and by Fries rearrangement of corresponding diacetyloxycalix[4]arene dimethyl ether 5 respectively. Diametrically substituted p-diacetylcalix[4]arene 8 was also prepared by Fries rearrangement of calix[4]arene tetraacetate 7 using a limited amount of $AlCl_3$.