Adsorption properties of copper ion-exchanged mordenite (CUM) for dinitrogen molecules ( N 2 ) were examined at 298 K. The intensive IR absorption band observed at 2299 cm-' was attributed to the NZ species strongly adsorbed on CUM. The interaction of NZ with CUM is explored using adsorption calorimetry, X-ray absorption fine structure (XAFS), electron spin resonance (ESR), and photoemission spectroscopy. The differential heat and entropy of adsorption for N2 on CUM were 60 kJ mol-' and 60 J K-' mol-' at the initial stage of adsorption, respectively, and those for NZ on NaM (sodium-type mordenite) gave the values of 32 kJ mol-' and 130 J K-' mol-', revealing that the N2 molecules are in the localized state resulting from the strong interaction with CUM. The monolayer capacity is estimated to be 4.12 cm3 g-' for NZ on CUM-150, which gives a value of 0.22 for the Nz/Cu ratio. XAFS and emission data for CUM degassed at 873 K exhibit pair bands at 8.983 and 8.994 keV and 18 700 and 20 800 cm-I, respectively. The former pair band is assigned to the 1s-4p transition, and the latter pair band is assigned to the 3d94s1-3dl0 transition. It is also found that the ESR band intensity for Cu(I1) decreases with increasing pretreatment temperature. These spectral data are reasonably explained by assuming the presence of Cu(1) species in mordenite. It is proved from the emission data that the adsorption site including Cu(1) species easily formed by heat treatment at 873 K in vacuo is effective for N2 adsorption. Such easy conversion of Cu(II) to Cu(1) may be due to the spatial distribution of ion-exchanged sites on mordenite. The appearance of a strong IR band at 2299 cm-' is due to the adsorption of N2 on the Cu(1) species and to the induction of a transition moment by the strong field of this site. Although a rather high value of heat of adsorption might suggest chemisorption, it is made plausible that this type of N2 adsorption is physisorption.

The state of copper ion exchanged in ZSM-5-type zeolite has been investigated through the IR and adsorption-heat measurements at 301 K by using CO as a probe molecule. As a result, it was proved that there are at least three kinds of adsorption sites for a CO molecule on the copper ion-exchanged ZSM-5, which are responsible for the IR bands at 2159, 2149, and 2136 cm-1, as well as the differential adsorption-heats of 91, 82, and ∼70 kJ mol-1. Corresponding to these data, TPD also gives three desorption peaks at 363, 442, and 542 K. An excellent linear relationship has been established between the stretching vibrational frequencies due to the adsorbed CO species and the differential adsorption-heat values. When CO gas is introduced to the 723 K-treated sodium ion-exchanged ZSM-5, this sample provides the adsorption-heat of about 35 kJ mol-1 in the whole adsorption region studied and the weak IR bands at 2175 and 2112 cm-1. For the sodium ion-exchanged ZSM-5 and CO system, the above correlation does not hold in the same plot containing Cu−CO species. This fact is interpreted in terms of the difference in the nature of bonding between the electrostatic force for the sodium ion-exchanged ZSM-5 and CO system and the covalent nature for the copper ion-exchanged ZSM-5 and CO system. More detailed discussions are also made on the nature of the Cu−CO bond.

The specific adsorption property of copper-ion-exchanged ZSM-type zeolite (CuZSM-5) for dinitrogen molecules (N 2 ) has been elucidated by methods such as infrared (IR) and emission (ES) spectroscopy and by the measurements of heat of adsorption and adsorption isotherms of N 2 and CO. In the IR spectra an intense band appears at 2295 cm -1 , which is attributed to the adsorbed N 2 species. The amount of adsorbed CO, as well as the adsorbed N 2 , increases with increasing copper-ion-exchange level of the ZSM-5 sample. By use of CO as a probe molecule, it was found that on the 873 K treated CuZSM-5 sample there are at least three types of adsorption sites available for CO adsorption; these are responsible for giving the IR bands due to the adsorbed CO species at 2159, 2151, and 2135 cm -1 . The adsorption behavior of N 2 molecules on the samples, which have various copper-ion-exchange levels and preadsorbed CO species, has been investigated, and it was found that the 2151 cm -1 band in the IR spectra reflects an N 2 adsorption site. Emission spectra were also obtained at each step of N 2 adsorption; the emission band due to the exchanged copper-ion species decreases in intensity with increasing pressure of N 2 . These results can be interpreted as follows. The monovalent copper ion (Cu + ) formed during the evacuation of the sample at 873 K acts as an effective site for N 2 adsorption. Moreover, the site responsible for giving the IR band at 2151 cm -1 and the ES band at 18500 cm -1 plays an important role in the N 2 adsorption. By reference to the results of X-ray absorption fine structure (XAFS) measurements reported previously, it is thought that the active site, i.e., Cu + species, for N 2 adsorption interacts with the lattice oxygen and with CO or N 2 molecules to produce a pseudotetrahedral four-coordination structure. The relation between the heat values and the frequency of the IR band due to the adsorbed CO species gives a linear regression, which indicates that σ-bonding is predominantly operative in the bonding of Cu + with CO or N 2 molecule.

The peculiar feature of copper ion-exchanged mordenite in dinitrogen (N 2 ) adsorption has been investigated through the measurements of infrared (IR) and emission spectra (ES) and X-ray absorption fine structure (XAFS). IR spectra provided the definitive evidence for the existence of at least two kinds of adsorption sites on the 873 K-treated copper ion-exchanged mordenite; the absorption bands centered at 2160 and 2150 cm -1 appeared when CO molecules were adsorbed. The adsorbed species assigned to the former band was desorbed at 573 K in Vacuo and that to the latter one at 473 K. It was found that the site responsible for the latter band acts as effective sites for N 2 adsorption. XAFS spectra also showed new bands due to the CO adsorption on copper ion at 1.48 Å, 2.52 Å, and 8.981 keV, together with bands at 1.85 Å and 8.993 keV. The former set of bands was concomitant with the appearance of an IR band at 2150 cm -1 due to the adsorbed CO species. The two bands (at 8.981 and 8.993 keV) observed in the XAFS spectra for the CO-adsorbed sample are explained in terms of the formation of a planar three-or four-coordinate site through the reaction of copper ions with CO molecules. CO adsorption also caused a significant shift of the emission band from 470 to 430 nm. This band reverted to the original position by evacuating the sample at 473 K, accompanying a liberation of CO. This makes possible the interpretation that the adsorption site responsible for respective bands at 2150 cm -1 in IR, at 430 nm in ES, and at 8.981 keV in XAFS spectra through the interaction with CO molecules is effective for N 2 adsorption at ambient temperature.

The formation constant (KZnL), enthalpy and entropy changes (ΔH and ΔS), and deprotonation constant (Ka) of coordinated water for hydrated zinc(II)–triamine (1 : 1) complexes (N3–Zn-(OH2)n (N3 = diethylenetriamine (dien), N-(2-aminoethyl)-1,3-propanediamine (epd), dipropylenetriamine (dpt), cis,cis-1,3,5-triaminocyclohexane (tach), and 1,5,9-triazacyclododecane ([12]aneN3)) were determined by potentiometry. The pKa linearly increased along with an increase in -ΔH, and was explained in terms of a ligand–ligand interaction through the N3–Zn-O bond on the bases of a thermodynamic analysis and strain-energy calculation (MM2). The zinc(II) complex-promoted hydrolysis of 2,4-dinitrophenyl diethyl phosphate was investigated in 1% (v/v) methanol–water; the rate constants linearly increased along with decreases of pKa and −ΔH. This fact indicates that the hydrolysis proceeds via a concerted direct nucleophilic attacking mechanism of the coordinated hydroxide ion, in which the phosphate ester coordinates to the zinc(II) ion. X-ray structure analyses for synthesized model complexes, [Zn(OAc)(dien)](ClO4), [{Zn(dpt)}3(CO3)](ClO4)4·NaClO4, and [Zn(OAc)(tach)](ClO4), are also reported.

We have prepared MCM-41 samples having good crystallinity and possessing a small amount of surface hydroxyl groups (0.48 OH nm-2) through extensive aging of a mixed solution of silica and surfactant in the temperature range from 308 to 413 K. The MCM-41 sample thus prepared exhibits excellent resistance to water, and its structure survives even after treating it in boiling water for more than 1 week. The surface and acidic properties of this sample were examined by X-ray diffraction, 29Si magic-angle spinning NMR, adsorption isotherms of dinitrogen and water molecules, and Fourier transform infrared measurements to determine the factors governing an adsorption feature and affecting the acidic property of the MCM-41 samples. The synthesized sample gives a sharp band centered at 3745 cm-1 tailing toward the lower wavenumber side. This band was deconvoluted into three components (3749, 3736, and 3715 cm-1), which were assigned to the stretching vibrations of the respective OH groups:  a free OH (silanol), a geminal OH, and a terminal OH group of the hydrogen-bonded species. The data obtained by utilizing CO as a probe molecule provide useful information on the acidic nature of the surface OH groups. A linear relationship between Δν OH (shift in wavenumber of OH stretching vibration) and ν CO (stretching vibration of adsorbed CO) has been found to hold in the present system. It is concluded that the newly formed OH groups, which give strong IR bands at 3736 and 3715 cm-1, after water vapor and boiling water treatments, are responsible for the sites that are generally recognized as the strongly acidic sites existing in MCM-41, compared with the acidity of free silanol groups. The freshly prepared sample shows characteristic behavior in the differential heat of adsorption of water, q diff, due to lateral interaction of the adsorbed water molecules. This is a different behavior from water adsorbed on the hydrated and boiled samples, indicating the homogeneous nature of the surface of the as-prepared sample for adsorbing water molecules. All properties of such materials should be discussed by taking account of the types of surface OH groups; the surface of MCM-41 having a smaller number of acid sites exhibits a prominent feature for water adsorption. From our results, it was concluded that the surface crystallinity of the sample plays a pivotal role in protecting the sample against attack by water and also in the adsorption behavior of adsorbates, such as water and CO molecules.

Nanodot BaTiO 3 supported LiCoO 2 cathode thin films can dramatically improve high-rate chargeability and cyclability. The prepared BaTiO 3 nanodot is <3 nm in height and 35 nm in diameter, and its coverage is <5%. Supported by high dielectric constant materials on the surface of cathode materials, Li ion (Li + ) can intercalate through robust Li paths around the triple-phase interface consisting of the dielectric, cathode, and electrolyte. The current concentration around the triple-phase interface is observed by the finite element method and is in good agreement with the experimental data. The interfacial resistance between the cathode and electrolyte with nanodot BaTiO 3 is smaller than that without nanodot BaTiO 3 . The decomposition of the organic solvent electrolyte can prevent the fabrication of a solid electrolyte interface around the triple-phase interface. Li + paths may be created at non solid electrolyte interface covered regions by the strong current concentration originating from high dielectric constant materials on the cathode. Robust Li + paths lead to excellent chargeability and cyclability.

The IR technique in combination with adsorption microcalorimetry was used to picture the bonding nature of silver ion exchanged or supported on solid materials, such as ZSM-5-type zeolite, aluminosilicate, and SiO2, by utilizing CO as a probe molecule. It has become apparent that there exists an adsorption site on which the CO molecule is adsorbed to give an IR absorption band:  IR band at around 2193 cm-1 for silver-ion exchanged ZSM-5 (AgZSM-5) and aluminosilicate (Ag/SiO2·Al2O3), and at 2177 cm-1 for silver-ion supported SiO2 (Ag/SiO2). The CO adsorption took place accompanying a large heat evolution of 100−80 kJ mol-1 on the former two samples and relatively small heat of 70−40 kJ mol-1 on the latter sample; silver ions exchanged with protons acting as Brønsted acid sites are responsible for the strong adsorption sites for CO adsorption. Taking account of the relationship between the differential heat of adsorption (q diff) and the stretching vibrational frequency of adsorbed CO (ν CO), it was concluded that the electrostatic interaction is dominantly operative in these systems. The large adsorption heats in the initial stage of CO adsorption on the AgZSM-5 and Ag/SiO2·Al2O3 samples may be successfully explainable by considering a little contribution of σ-bonding in addition to the electrostatic interaction. The quantum chemical calculation was performed to justify the two types of ion-exchange model for silver ion coordinated to two or three lattice oxygen atoms in AgZSM-5, as well as to clarify the bonding nature between the exchanged silver ion and CO molecule. As the results, the two-coordinated silver ions in AgZSM-5 can adsorb CO molecules and give the values of about 100 kJ mol-1 and 2193 cm-1, and the three-coordinated silver ions weakly adsorb CO to give the values of about 80 kJ mol-1 and 2184 cm-1. These adsorption energies are much smaller and the stretching frequencies due to the adsorbed CO are higher, compared with the case of CO adsorption on copper-ion exchanged ZSM-5 (CuZSM-5). From these results it can be interpreted that the dominant force operating in the AgZSM-5−CO system is electrostatic attraction, as is different from the case of CuZSM-5−CO system in which the σ-donation is dominant in the bonding. This difference is explained by taking account of the differences in energy gap between 4d−5s for silver ion and 3d−4s for copper ion; in the former case the hybridization of orbital is limited to result in a large σ-repulsion. The present experiment clearly proved that the evaluation of bonding nature from the relationship between q diff and ν CO is useful in the characterization of exchanged ions. The specific bonding nature between copper ion (Cu+) exchanged in ZSM-5 and CO molecule was also clarified.