Acylation of an intermediate tetrahydroxoplatinum(IV) complex, $[Pt(OH)_4(dach)]$ (dach = $trans-(\pm)-12-di-aminocyclohexane)$, with one or two kinds of carboxylic anhydrides in stepwise manner afforded various car-boxylatoplatinum(IV) complexes, $[Pt(O_2CR)\chi(OR’)4-\chi(dach)]$ (R = $(CH_2)_3CH_3$ or $C(CH_3)_3$, R’ = H or $OCCH_3$, and $\chi$ = 1-4) with a wide range of lipophilicity. The title complexes were subjected to bioassay using the murine leukemia L1210 cell line, and in particular, their in vivo oral antitumor activity was attempted to correlate with their lipophilicity and water solubility. The most orally active complex exhibited intermediate lipophilicity and water solubility, but it has been found that an exact relationship between the lipophilicity and oral anticancer activity could not be established, since the lipophilicity of the complexes is not the sole parameter to determine the oral activity. One of the important intermediate complexes partially substituted was subjected to X-ray anal-ysis for positit of the substituted group: $[Pt(OPiv)_3(OH)(dach)]$ crystallizes in the tetragonal sys-tem, space group $P42_1c$ with a = 21.161(3) $\AA$, b = 21.161(6) $\AA$, c = 12.816(3) $\AA$, $\alpha=\beta=$ r $=90^{\circ}$, V = 5739(2) $\AA^3$ and Z = 8.

The equilibrium geometrical structures of silver atom clusters at their electronic ground states have been theo-retically determined by using the nonrelativistic semiempirical INDO/1 method. The clusters investigated are Agn, Agn+, and Agn- (n = 7 , 8, 9). In order to find the most stable structure, i.e., the global minimum in energy hypersurface, geometry optimization and energy calculation processes have been repeatedly performed for all the possible graphical models by changing the bond parameters (resonance integral values). The heptamers are pentagonal bipyramidal-Ag7(D5h), Ag7+ (D5h), Ag7- (D5h); the octamers are pentagonal bipyramidal with one atom capped-Ag8(D2d), Ag8+ (Cs), Ag8- (D2d); the nonamers are pentagonal bipyramidal with two atoms capped -Ag9(C2v), Ag9+ (C2v), Ag9- (C2v). Our structures are in good agreement with those by ab initio calculations ex-cept for the anionic Ag9- cluster. And it is noted that the INDO/1 method can accurately predict the Ag cluster geometries when a proper set of bond parameters is used.

Solvolyses of methanesulfonyl chloride in water, $D^2O$, $CH^3OD$, and in aqueous binary mixtures of acetone, eth-anol and methanol are investigated at 25, 35 and $45^{\circ}C.$ The Grunwald-Winstein plot of first-order rate con-stants for the solvolytic react ion of methanesulfonyl chloride with YCl (based on 2-adamantyl chloride) shows marked dispersions into three separate lines for three aqueous mixtures with a small m value (m < 0.30), and shows a rate maximum for aqueous alcoholic solvents. Stoichiometric third-order rate constants, kww and kaa were calculated from the observed first-order rate constants and (kaw + kwa) was calculated from the kww and kaa values. The kinetic solvent isotope effects determined in water and methanol are consistent with the proposed mechanism of the general base catalyzed and/or SAN/SN2 reaction mechanism for methanesulfonyl chloride solvolyses based on mass law and stoichiometric solvation effect studies.

The addition effect of $CH^3Br$ on the ignition of methane was investigated in the temperature range of 1537-1920 K behind reflected shock waves. The ignition delay times were measured by the sudden increase of pres-sure and OH emission in the $CH_4-O_2-Ar$ system containing small amount of $CH_3Br.$ The delay times of mix-tures with $CH_3Br$ were shorter than those without $CH_3Br.$ The promotion of ignition by $CH_3Br$ was caused by the relative fast decomposition rate in additive. To clarify the addition effect of $CH_3Br$ from the viewpoint of the reaction mechanism, computational analyses were performed in $CH_4-CH_3Br-O_2-Ar$ mixtures.

Direct reaction of elemental silicon with a mixture of (dichloromethyl)silanes 1 $[Cl_3-nMenSiCHCl_2:$ n = 0 (a), n = 1(b), n = 2(c), n = 3(d)] and hydrogen chloride has been studied in the presence of copper catalyst using a stirred bed reactor equ ipped with a spiral band agitator at various temperatures from $240^{\circ}C$ to $340^{\circ}C.$ Tris(si-lyl) methanes with Si-H bonds, 3a-d $[Cl_3-nMenSiCH(SiHCl_2)_2]$, and 4a-d $[Cl_3-nMenSiCH(SiHCl_2)(SiCl_3)]$, were obtained as the major products and tris(silyl)methanes having no Si-H bond, 5a-d $[Cl_3-nMenSiCH(SiCl_3)_2]$, as the minor product along with byproducts of bis(chlorosilyl)methanes, derived from the reaction of silicon with chloromethylsilane formed by the decomposition of 1. In addition to those products, trichlorosilane and tetra-chlorosilane were produced by the reaction of elemental silicon with hydrogen chloride. The decomposition of 1 was suppressed and the production of polymeric carbosilanes reduced by adding hydrogen chloride to 1. Cad-mium was a good promoter for and the optimum temperature for this direct synthesis was $280^{\circ}C$.

[Fe II Fe III $BPLNP(OAc)_2](BPh_4)_2$ (1), a new model for the reduced form of the purple acid phosphatases, has been synthesized by using a dinucleating ligand, 2,6-bis[((2-pyridylmethyl)(6-methyl-2-pyridylmethyl)ami-no)methyl]-4-nitrophenol (HBPLNP) . Complex 1 has been studied by electronic spectral, NMR, EPR, SQUID, and electrochemical methods. Complex 1 exhibits two strong bands at 498 nm $(\varepsilon=$ 2.6 ${\times}10^3M-^1cm-^1)$ and 1363 nm $(\varepsilon=$ 5.7 ${\times}10^2M-^1cm-^1)$ in $CH_3CN.$ These are assigned to phenolate-to-FeIII and intervalence charge-transfer transitions, respectively. NMR spectrum of complex 1 exhibits sharp isotropically shifted resonances, which number is half of those expected for a valence-trapped species, indicating that electron transfer between FeⅡ and FeⅢ centers is faster than NMR time scale at room temperature. Complex 1 undergoes quasireversible one-electron redox processes. The $FeIII_2/FeIIFeIII$ and $FeIIFeIII/FeII_2$ redox couples are at 0.807 and 0.167 V ver-sus SCE, respectively. It has Kcomp = 5.9 ${\times}$10 1s(acetato) ligand combination sta-bilizes a mixed-valence FeIIFeIII complex in the air. Interestingly, complex 1 exhibits intense EPR signals at g = 8.56, 5.45, 4.30 corresponding to mononuclear high-spin FeⅢ species, which suggest a very weak magnetic coupling between the iron centers. Magnetic susceptibility study shows that there is a very weak antiferromag-netic coupling (J = $-0.78cm-^1$, H = $-2JS_1${\times}$S_2)$ between FeII and FeIII centers. Thus, we can suggest that complex 1 has a very weak antiferromagnetic coupling between the iron centers due to the electronic effect of the nitro group in the bridging phenolate ligand.

Vibrational properties of dopamine neutral species in powder state have been studied by means of the normal mode analysis based on the force constants obtained from the density functional calculation at B3LYP level and the results of Fourier trans form Raman and infrared spectroscopic measurements. Ab initio calculation at MP2 level shows that the trans conformer of dopamine has higher electronic energy about 1.4 kcal/mol than those of the gauche+ and the gauche-conformers, and two gauche conformers have almost the same energies. Free energies calculated at HF and B3LYP levels show very similar values for three conformers within 0.3 kcal/mol. Empirical force field has been constructed from force constants of three conformers, and refined upon ex-perimental Raman spectrum of dopamine to rigorous values. The major species of dopamine neutral base in the powder state is considered a trans conformer as shown in the crystallographic study of dopamine cationic salt.

The water-soluble poly(methoxyethoxy-aminoarlyoxy phosphazene) has been synthesized and investigated as a polymeric carrier molecule for the covalent attachment of bioactive agents. The synthetic procedures were developed first through the use of cyclic trimeric model systems. These model systems were utilized for the synthesis of polymeric analogues containing bioactive side groups. The sodium salts of 2-methoxyethanol and 4-acetamidophenol were allowed to react with $(NPCl_2)_3$ or $(NPCl_2)n$ or to yield derivatives of type $[NP-(OCl_2CH_2CH_2OCH_3){\chi}(OArNHCOCH_3)y]_3or$ n. The 4-acetamido groups were then hydrolyzed to 4-amino-phenoxy units with potassium tert-butoxide. Coupling reactions between amino group and N-acetylglycine was accomplished with the use of dicyclohexylcarbodiimide. Their properties and structural characterization are discussed.

We present the effects of temperature (between 10 K and 298 K) and of hole concentration on the frequency and intensity of characteristic phonons in polycrystalline $La_2CuO_4-related$ compounds using FT-IR spectros-copy. The influences of the concentration of carrier doped on the phonon modes are prominent in the IR spectra of $La_2CuO_4-related$ compounds. For $La_2-xSrxCuO_4({\chi}=$ 0.00, 0.03, 0.07, 0.10, and 0.15) and electrochemically (or chemically) oxidized $La_2CuO_4$, the intensities of the transverse oxygen mode around 680cm $-^1$ which cor-responds mainly to Cu-O(1) stretching vibration in the basal plane of CuO6 octahedron, are decreased and dis-appeared depending on the Sr-substitution rate and the amount of excess oxygen, while the longitudinal oxygen mode around 510 cm $-^1$ corresponding to the Cu-O(2) stretching in the basal plane of CuO6 octahedron are near-ly invariable. In particular, after two cycles of cooling-heating between 10 K and 298 K for these sample, the phonons around 680 cm $-^1$ are blue shif 13-15 cm $-^1$, while the phonons around 510 cm $-^1$ are nearly constant. The introduction of the charge carrier by doping would give rise to the small contraction of CuO6 oc-tahedron as Cu $^3+$ requires a smaller site than Cu $^2+$, which results in the shortening of the Cu-O(1) bond length and Cu-O(2) bond length with the increased La-O(2) bond length. These results in the frequency shift of the characteristic phonons. The IR spectra of $La_2Li0.5Cu0.5O_4$ which exhibits an insulator behavior despite the $Cu^3+$ of nearly 100%, corroborate our IR interpretations. The mode around 710 cm $-^1$ corresponding to Cu-O(1) stretching vibration is still strongly remained even at low temperature (10 K). Thus, we conclude that the con-duction electrons formed within $CuO_2$ planes of $La_2CuO_4-related$ superconductors screen more effectively the transverse oxygen breathing mode around 680 $cm-^1$ depending on the concentration of the doped charge carrier in $La_2CuO_4-related$ compounds, which might use as a superconductivity probe.

Catalytic copolymerization of diethyl dipropargylmalonate (DEDPM) and phenylacetylene (PA) by Mo(CO)6 and (toluene) Mo(CO)3/chloranil has resulted in the expected copolymer consiting of a polyene backbone with five-and/or six-membered rings and th e PPA structure. Both complexes exhibited not only varying degree of catalytic activity depending upon the relative mole ratio of two monomers but also characterize the types of coploymers. The former yields the polyene backbone containing only five-membered rings as well as PA while the latter produces the polymers consisting of both five-and six-membered ring structure. Comparative studies show that Mo(CO)6 exhibits reactivity toward DEDPM alone, thus catalyzing initially metathesis cyclopoly-merization of DEDPM followed by copolymerization with PA while the (toluene)Mo(CO)3/chloranil system shows affinity for both PA and DEDPM.

Dye-sensitized nanocrystalline rutile $TiO_2$ solar cells were prepared, and the influence of Li+ and 1,2-dimethyl-3-hexyl imidazolium ions in the electrolyte on the photovoltaic properties was compared. The electrolyte con-taining Li+ ions produced a lower open-circuit photovoltage than the electrolyte with 1,2-dimethyl-3-hexyl im-idazolium ions, suggesting that the adsorption of Li+ ions to the rutile $TiO_2$ surface causes a shift in the band edges toward more positive potentials. At the same time, both the short-circuit photocurrent and the maximum value of the incident-photon-current conversion efficiency (IPCE) of the electrolyte containing Li+ ions were relatively higher. Data analysis suggests that presence of adsorbed Li+ ions improves via the phenomenon of band-edge movement the charge-injection efficiency by altering both the energy and number of excited state levels of the dye that participate in electron injection.

A chromia-pillared clay has been prepared by ion exchange type intercalation reaction between the sodium ion in montmorillonite and the trimeric chromium oxyformate (TCF) ion, and by subsequent heat-treatment. The structural and thermal properties have been systematically studied by thermal analysis, powder XRD, IR spec-troscopy, and XAS. The gallery height of~6.8 $\AA$ upon intercalation of the TCF ion suggests that the $Cr_3O$ plane is parallel to the aluminosilicate layers. Even though the basal spacing of TCF intercalated clay decreases slightly upon heating, the layer structure was retained up to $550^{\circ}C$ as confirmed by XRD and TG/DTA. Ac-cording to the EXAFS spectroscopic analysis, it is identified that the (Cr-Cr) distance of 3.28 $\AA$ between vertex-linked CrO6 octahedra in TCF splits into 2.64 $\AA$, 2.98 $\AA$, and 3.77 $\AA$ due to the face-, edge-, and corner-shared CrO6 octahedra after heating at $400^{\circ}C$, implying that a nano-sized chromium oxide phase was stabilized within the interlayer space of clay.

Binding geometries of $[Ru(II)(110-phenanthroline)_2L]^2+$, complexes (where L = dipyrido [3,2-a:2',3'-c]phena-zine (DPPZ) or benzodipyrido[3,2-a:2',3'-c] phenazine (BDPPZ)) to poly(dG)${\cdot}$poly(dC)${\cdot}$poly(dC) + triplex DNA (CGC + triplex) has been investigated by linear dichroism and normal absorption spectroscopy. Analysis of the linear dichroism for the CGC+ triplex and $[Ru(II)(phen)_2BDPPZ]^2+$ complex indicates that the extended ligand of the metal complex lie perpendicular to the polynucleotide helix axis. Together with strong hypochromism and red shift in the interligand absorption region, we concluded that the extended BDPPZ or DPPZ ligand in-tercalated between the bases of polynucleotide. The spectral properties of the metal complexes bound to CGC+ triplex are similar to those bound to $poly(dA)[poly(dT)]^2$ triplex (Choi et al., Biochemistry 1997, 36, 214), sug-gesting that the metal complex is located in the minor groove of the CGC+ triplex.