The electronic structures and properties of the neutral and multiply charged C60n ions (n=2+ to 6-) with spin states have been investigated by semi-empirical MNDO calculations. In the ground state, C601- has the lowest total energy and the highest binding energy. The neutral C60 ion is supposed to have a high ionization potential and a high electron affinity. The HOMO and LUMO positions are lower in the cationic C60 than in the anionic C60. The LUMO energy becomes increasingly positive from C601- to C606- and the HOMO energy becomes increasingly negative from C602+ to C60. The HOMO-LUMO gap of the neutral C60 ion is higher than that of the multiply charged C60 ions. From the HOMO-LUMO gap, it seems reasonable to expect that electrons of the multiply charged C60 ions will be more polarizable than those of the neutral C60 ion. The HOMO and LUMO energies increase as the negative charge increases.

A light-emitting silicon material was prepared by electrochemical etching of n-Si single crystal wafers in a solution of hydrofluoric acid and ethanol. Visible photoluminescence from the silicon was inhomogeneous and decayed rapidly in the ambient laboratory conditions or with photoirradiation. Substantial improvements in photoluminescence which include little-dependent luminescence peak energy with excitation energy variation and longer-lasting room temperature visible photoluminescence were achieved when the surface of photoluminescent silicon material was derivatized with the surface modifier of octadecylmercaptan. Surface modification of the photoluminescent silicon was evidenced by the measurements of contact angles of static water drops, FT-IR spectra and XPS data, in addition to changed photoluminescence. Similar improvements in photoluminescence were observed with the light-emitting silicon treated with dodecylmercaptan, but not with octadecane. The present results indicate that sulfurs of octadecylmercaptans or dodecylmercaptans appear to coordinate the surface Si atoms of LESi and perturb the surface states to significantly change the luminescent characteristics of LESi.

A comparative study of different torches in the Microwave Induced Plasma is reported. Three types of torches that have been used in this area are characterized and compared with each other. Especially, recently developed laminar flow torches have been optimized in design and analytical performances. The ratio of inner to outer tubes is found to be the most important parameter. As inner tube size increases, recirculating region also increases and consequently, sensitivity becomes better. An optimized laminar flow torch has been coupled to a gas chromatography and examined for halogen compounds. Detection limits are 25 pg s-1 for Cl and 12 pg s-1 for Br. These values are improved over the conventional laminar flow torch.

The structure and electronic properties of the Si(100) surface is studied using the atom superposition and electron delocalization method. The energy released when the symmetric dimer surface is reconstructed to form the buckled dimer surface with p(2X2) symmetry is calculated to be 0.99 eV per dimer in the case of ideal clean surfaces. This indicates that the surface dimer buckling is intrinsic from the viewpoint of thermodynamics. The relaxation energy, when water is adsorbed on the clean symmetric dimer surface to form the buckled dimer surface, is 2.25 eV per dimer for appropriate coverages. These results show that H2O molecule could induce a reconstruction of the surface structure through adsorption. The buckling of the surface dimer is, therefore, more favorable under the existence of water vapour. This conclusion supports the recently obtained experimental observations by Chander et al.

PVC-based calcium-selective electrodes doped with ETH 129 usually suffer from a shift in the standard potential when they are in contact with protein-containing solutions (e.g. blood serum) after being calibrated with aqueous standards. The shift is due to the development of asymmetry potential in inherently symmetric PVC membranes through the contamination of outer membrane surface by proteins in the biological samples. Membranes prepared with polyurethane showed much reduced shifts in terms of standard potential. This study was performed with a flow-injection system following a protocol designed to observe minor shifts in baseline potential. Other electrochemical properties of the system, including selectivity and response slope, were similar to those obtained with regular PVC-based ones. PVC-based calcium selective membrane electrodes, doped with commonly used ETH 1001, were also tested to compare their electrochemical performances.

The reaction of acetophenone 1-ureidoethylidenehydrazones 6 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine in dichloromethane provides a general route to 1-(1-phenylethenyl)-5-(N-substituted amino)-1,2,4-triazoles 11 via the electrocyclization of the expected azino carbodiimide intermediates 9 to give the resonance stabilized azomethine imine 10a followed by a proton abstraction from the methyl group by amide anion. However, the same reaction of benzaldehyde 1-ureidoethylidenehydrazones 5 was unsuccessful. Under the same conditions, the reactions of benzaldehyde 1-N-acylureidoethylidenehydrazones 7 or acetophenone 1-N-acylureidoethylidenehydrazones 8 afforded 4H-1,2,4-triazolo[1,5-c][1,3,5]oxadiazines 16 or 17 via the zwitterionic species 15, or a [4+2] intramolecular cycloaddition from the carbodiimide intermediates 14, respectively.

The overtone of the ν2 vibrational mode in Cr(CO)6 are observed for the first time in cyclohexane and methanol at both the 266 and 213 nm excitations. The appearance of the overtones due to the displacement of the electronic excited state with respect to the ground state along the ν2 vibrational mode is interpreted in terms of wavepacket concept and molecular orbital (MO) theory. Our Raman results suggest a new interpretation for the excited state potential.

A topological theory has been introduced to evaluate the degree of complexation and the viscosity of polymer complexes by extending the theory of Iliopoulos and Audebert for aqueous polymer solutions. The previous theory of Iliopoulos and Audebert has offered only a semiquantitative theoretical model for polymer complex systems, whereas our present work gives a general theoretical model applicable to all the polymer complex systems. Their theories considered only the physical property term caused by the displacement of complexed points between polymer solute chains, while our theory deals with all the physical effects, caused by the displacement of complexed points entangled points in polymer solute chains. There have been predicted the characteristics of physical properties from the expression. It is exposed that the predictive values show good agreement with the experimental data for polymer complexes.

The bulk photopolymerization of methyl methacrylate (MMA) with primary arylsilane (e.g., phenylsilane) and various primary alkylsilanes (e.g., benzylsilane, 3-phenoxyphenyl-1-silabutane, 3-naphthyl-1-silabutane, and 3-chlorophenyl-1-silabutane) was performed to produce poly(MMA)s containing the corresponding silyl moiety as an end group. It was found for the phenylsilane that while the polymerization yields increased and then decreased with a turning point at the molar ratio of MMA:silane=10:1 as the relative silane concentration increases, the polymer molecular weights decreased, and the TGA residue yields and the relative intensities of SiH IR stretching bands increased with increment of molar ratio of silane over MMA. The photopolymerization yield of MMA with the arylsilane was found to be higher than those with the alkylsilanes and without the silanes. Thus, the silanes seemed to significantly influence on the photopolymerization as both chain initiation and chain transfer agents.

The reactivity of superoxide ion (O2-.) with halogenated substrates is investigated by cyclic voltammetry and rotated ring-disk electrode method in aprotic solvents. The more positive the reduction potential of the substituted nitrile, the more facile is nucleophilic displacement by O2-.. The reaction rates of halogenonitriles with O2-. vary according to the leaving-group propensity of halide (Br > Cl > F). The relative reaction rates of other substituted nitriles are in the order of electron-withdrawing propensity of the substituent group (CN > C(O)NH2 > Ph ≒ CH2CN). The reaction of O2-. with dihalocarbons indicates that five-membered rings can be rapidly formed by the cyclization of substrate and O2-., and the relative rates of cyclization depend on the number of methylenic carbons {Br(CH2)nBr, [n=1 < 2 < 3 > 4 > 5]}. Mechanisms are proposed for the reaction of O2-. with halogenated substrates.

A convenient method for the synthesis of N-substituted isoindolin-1-ones is disclosed in palladium(0)-catalyzed heterocyclization of o-bromobenzylbromide with carbon monoxide (CO) and primary amines in DMF at 100 ℃.

Reaction of arachno-S2B7H8- with either THF or 1,2-dimethoxyethane upon refluxing condition results in the formation of the previously known compound hypho-S2B7H10-. Protonation of hypho-S2B7H10- with HCl/Et2O generates hypho-2,5-S2B7H11 in good yield. This hypho-S2B7H10- anion has been employed to generate a series of new nido-, arachno-, and hypho-metalladithiaborane clusters. Reaction of the anion with Cp(CO)2FeCl results in direct metal insertion and the formation of a complex containing the general formula (η5-C5H5)FeS2B7H8. Spectroscopic studies of nido-6-CpFe-7,9-S2B7H8 Ⅰ demonstrated that compound Ⅰ was shown to have an nido-type cage geometry derived from an octadecahedron missing one vertex, with the iron atom occupying the three-coordinate 6-position in the cage and the two sulfurs occupying positions on the open face of the cage. Reaction of hypho-S2B7H10- with CoCl2/Li+[C5H5]- gave the previously known complex arachno-7-CpCo-6,8-S2B6H8 Ⅱ. Also, the reaction of the anion with [Cp*RhCl2]2 gave the complex arachno-7-Cp*Rh-6,8-S2B6H8 Ⅲ, the structure of which was shown to be that of complex Ⅱ. The similarity of the NMR spectra of Ⅱ and Ⅲ suggest that Ⅲ adopts cage structure similar to that previously confirmed for Ⅱ. A series of 9-vertex hypho clusters in which the sulfur atoms are bridged by different species isoelectronic with a BH3 unit, such as HMn(CO)4 or SiR2 have been prepared. Compounds Ⅳ,Ⅴ and Ⅵ are each 2n+4 skeletal electron systems and would be expected according to skeletal electron counting theory to adopt hypho-type polyhedral structures derived from an icosahedron missing three vertices. The complex hypho-1-(CO)4Mn-2,5-S2B6H9 Ⅳ was obtained by the reaction of the anion with (CO)5MnBr and has been shown from spectroscopic data to consist of a (CO)4Mn fragment bound to the two sulfur atoms S2 and S5 of hypho-S2B7H10-. Also, similar hypho-type complexes hypho-1-R2Si-2,5-S2B6H8 (R=CH3 Ⅴ, R=C6H5 Ⅵ) have been prepared from the reaction of hypho-S2B7H10- with R2SiHCl.

Poly(dichlorophosphazene) having low molecular weight (M&bar;w∼104) was synthesized by the thermal reaction of hexachlorocyclotriphosphazene in the presence of excess AlCl3 (>2%) as catalyst. Using the poly(dichlorophosphazene), poly[bis(ethylglycino)phosphazene], poly[bis(glycinemethylamido)phosphazene], and poly[(glycinemethylamido)(methylamino)phosphazene] were prepared. Diammineplatinum(Ⅱ) complex cation was introduced into these derivatized phosphazene polymers, and the resultant polymers containing the platinum(Ⅱ) moiety were charaterized by means of elemental analysis, IR and NMR spectroscopies, and then subjected to in vitro and in vivo assays of antitumor activity.

New cyclophanes having multilactam linkages were synthesized and characterized. One-pot coupling reaction of 2,6-pyridinedicarbonyl dichloride and a diamine gave a tetralactam, a hexalactam, and a octalactam in good yields. The TLC behaviour, the molecular symmetry shown by 1H NMR spectrum, and the fragmentation patterns shown by FAB mass spectrum of the octalactam support its monocyclic structure.

A complete solid solution (SrLaAl1-xNixO4) between insulating SrLaAlO4 and metallic SrLaNi(Ⅲ)O4 oxides were prepared under high oxygen pressure (1.5 kbar, 800 ℃). They have tetragonal K2NiF4-type structure in all the solid solution range. Compared with lattice parameters of the same solid solution prepared under normal condition (1 bar, 1200 ℃), large decrease in the c-parameter was induced by high pressure treatment while no noticeable variation of the a-parameter was observed. Although marked changes of structural parameters, magnetic susceptibilities, and electron paramagnetic resonance spectra were consistently occurred before and after x=0.5, overall behaviors were essentially the same with those of solid solution prepared under normal condition. Such a phenomenon is explained by assuming the formation of partially filled narrow σ*x2-y2 band for x>0.5. Lattice contraction along the c-axis by high pressure treatment seems not to broaden this band. Particularly, the continuous absorption characteristic of a high free carrier concentration for x>0.5 and the absence of Ni-O in-plane stretching mode in the infrared absorption spectra supports this picture. However, the conductivities increasing with temperature for all solid solution suggest that some localization character, of probably Anderson type, remains for x>0.5.

The p-xylyl radical has been produced in a jet from the precursor p-xylene with a corona excited supersonic expansion. Rotationally cooled vibronic emission spectra in the transition of 12A2→12B2 of the p-xylyl radical have been recorded using a Fourier transform spectrometer. The spectra were analyzed on the basis of the known vibrational frequencies and the bandshapes given by the rotational selection rules.

The polycondensations of bis(2-hydroxyethyl) naphthalate were kinetically investigated in the presence of various metallic compounds as catalysts at 295 ℃. The effect of the catalyst nature in the polycondensation has been studied. The order of catalytic activity on the formation of poly(ethylene 2,6-naphthalate) was found to be related to the stability constants which are indicated in an index of the catalytic activity.

The catalyzed polycondensations of bis(2-hydroxyethyl) naphthalate were kinetically investigated in the presence of various antimony compounds as a catalyst. The polymerization were investigated with various ligand types of antimony oxides, various concentrations of antimony triacetate and titanium/antimony mixed catalysts. The time to reach the maximum molecular weight was remarkably changed in each case. With increasing the concentration of antimony acetate, the propagation rate was largely increased, while the degradation rate was slightly decreased. It also can be seen that the propagation and degradation rate were larger influenced by the equimolecular titanium/antimony mixed catalyst than other mixed catalysts. The temperature dependence of bis(2-hydroxyethyl) naphthalate with antimony triacetate also has been studied. From the results, it was found that the propagation rate was less influenced by a temperature change than the degradation rate.

A measure of stabilities (-ΔHo) and resonance delocalization (-Δq(Cα+)) for some carbocations has been estimated using the semiempirical AM1 method. The stability (-ΔHo) of carbocations can be correlated with the sensitivity (m) of localized cations to the solvent ionizing power scale Y, whereas the extent of resonance delocalization (-Δq(Cα+)) can be correlated with the sensitivity (h) of delocalized cations to the solvent ionizing power scale Ⅰ. It has been shown that two solvent ionizing power scales Y and I have in general opposite signs so that effects of electrostatic solvation are opposite for the localized and delocalized cationic charges. The use of two different solvent scales for a substrate with delocalizable cationic charge is not only prerequisite to the proper correlation of solvolysis rates but also is justified.

Bis(silyl)alkylbenzenes such as bis(1-sila-sec-butyl)benzene (1) and 2-phenyl-1,3-disilapropane (2) were prepared in high yields by reduction of the corresponding chlorosilanes with LiAlH4. The dehydropolymerization of 1 and 2 was carried out with group 4 metallocene complexes generated in situ from Cp2MCl2/Red-Al and Cp2MCl2/n-BuLi (M=Ti, Hf), producing two phases of polymers. The TGA residue yields of the insoluble polymers were in the range of 64-74%. The molecular weights of the soluble polymers produced ranged from 700 to 5000 (Mw vs polystyrene) and from 500 to 900 (Mn vs polystyrene). The dehydropolymerization of 1 and 2 seemed to initially produce a low-molecular-weight polymer, which then underwent an extensive cross-linking reaction of backbone Si-H bonds, leading to an insoluble polymer.

The Schlo'gl model with the first order transition for a photochemical reaction is considered to study the dynamic behaviors in the neighborhood of the Gaussian white noise by obtaining the explicit results of the time-dependent variance and time correlation function with the aid of approximate methods based on the stationary properties of the system. Then, we discuss the effect of external noise strength on the stability of the model at steady states in detail.

The method for the Schlo"gl model with the first order transition is extended to the Scho;gl model with the second order transition for a photochemical reaction. We obtain the explicit results of the time-dependent average and the time correlation function at the unstable steady state of the model in the neighborhood of the Gaussian white noise and then discuss the effect of noise on the dynamic properties.

Three inherently chiral calix[4]arenes 3-5 were synthesized as racemate starting from the ethylation at 1.3-distal hydroxy groups of calix[4]arene 2 which has two phenyl groups at upper rim in AABB fashion, and then two remaining hydroxy groups were acetylated by treatment with acetyl chloride in the presence of NaH to produce calix[4]arene 4. Treatment of 4 with AlCl3 under Fries rearrangement conditions, only one acetyl group was rearranged to the para-position to afford calix[4]arene 5 with AABC substitution pattern at the upper rim of calix. The structure of chiral calix[4]arenes were confirmed based on NMR and massspectra.