Toyotoshi Ueda

Covalent immobilization of DNA on diamond and its verification by diffuse reflectance infrared spectroscopy

Immobilization of DNA on diamond surfaces and detection of its covalently bonded nature were explored by direct spectroscopic analysis. Fine diamond powder was successfully modified by oxidation, followed by esterification. DNA covalently immobilized onto diamond through ester linkage was detected by diffuse reflectance infrared spectroscopic analysis.

Photocatalytic activity of ultra-fine rutile in methanol-water solution and dependence of activity on particle size

Abstract Ultra-fine rutile was prepared from titanium tetrachloride below 100°C and calcined in order to increase particle size. The effect of the particle size of the rutile on the photocatalytic activity in a methanol-water solution was observed in the range 120–1500 A. The activity increased inversely with the diameter.

Raman scattering tensors of tyrosine

Polarized Raman scattering measurements have been made of a single crystal of L-tyrosine by the use of a Raman microscope with the 488.0-nm exciting beam from an argon ion laser. The L-tyrosine crystal belongs to the space group P2(1)2(1)2(1) (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L-tyrosine-d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3-->ND3 and OH-->OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L-tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L-tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm-1 (benzene ring breathing), 642 cm-1 (benzene ring deformation), and 432 cm-1 (C alpha-C beta-C gamma bending).

Vibrational modes in thymine molecule from an ab initio MO calculation

Abstract Ab initio self-consistent field molecular orbital (SCF MO) calculations have been made of the thymine molecule for the equilibrium geometry, harmonic force constants, vibrational frequencies, vibrational modes, infrared intensities, and Raman intensities. The results have been correlated with the observed Raman and infrared spectra of thymine crystalline powder.

Raman tensors for the tryptophan side chain in proteins determined by polarized Raman microspectroscopy of oriented N-acetyl-l-tryptophan crystals

Abstract Polarized Raman spectra have been obtained from oriented single crystals of N -acetyl-l-tryptophan by use of a Raman microscope and 488.0 nm argon excitation. The crystal, of orthorhombic space group P2 1 2 1 2 1 , provides the relative Raman intensities I aa , I bb and I cc corresponding to the aa, bb and cc components of the crystal Raman tensor. The polarized Raman spectra of the crystal have been combined with depolarization ratios from solution spectra of randomly oriented N -acetyl-l-tryptophan and l-tryptophan to yield Raman tensors for each of the following vibrational normal modes of the indole moiety: N 1 H stretch (≈3416 cm −1 ), WI (≈1617 cm −1 ), W 2 (≈1576 cm −1 ), W 3 (≈1557 cm −1 ), W 4 (≈1487 cm −1 ), W 5 (≈1458 cm −1 ), W 6 (≈1424 cm −1 ), W 7 (≈1357 cm −1 ), W 7′ (≈1332 cm −1 ), W 16 (≈1010 cm −1 ) and W 18 (≈757 cm −1 ). These Raman tensors determined for the tryptophan residue in N -acetyl-l-tryptophan are proposed as being transferable to tryptophan side chains in proteins. A knowledge of Raman tensors for the tryptophan side chain should facilitate the determination of indole ring orientation in biological complexes amenable to investigation by the method of polarized Raman microspectroscopy.

Spectroscopic proof for intermolecular or intramolecular hydrogen bonds in ketoenol tautomers of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

Abstract The broad infrared bands of the polymorphic crystals of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) were assigned unequivocally by examining the IR spectra of solutions and Raman spectra. The strong band at 2550 cm −1 of a colourless crystal was attributed to an intermolecular hydrogen bond NH…OC of the NH keto form, and the strong band at 3100 cm −1 of a yellow crystal, to an intermolecular hydrogen bond OH…OC of the O(1)H enol forms.

Raman scattering tensors in thymine molecule from an ab initio MO calculation

Abstract Ab initio SCF MO calculations have been made of the thymine molecule for the permanent polarizability and the polarizability derivatives with respect to the normal coordinates. The latter correspond to the components of the Raman tensors, and each of these tensors was brought into a visualized form by a transformation of the tensor axes into the principal system. For a comparison with such computational findings, a polarized Raman spectroscopic measurement has been made of a single crystal of thymine with 488.0 nm excitation. For most of the in-plane vibrations, calculated tensors were found to be well correlated with the observed Raman scattering anisotropy. On the basis of such correlations, discussions are given as for the polarizability oscillations caused by the atomic displacements in the molecule.

Localized raman tensors in some biopolymers

Abstract A general survey is given of the relations between the anisotropy of the Raman scattering intensities of a crystal and the effective Raman tensor of the molecule corresponding to the molecular vibration in question. Some of the Raman tensors determined by the use of these relations are discussed. The Raman tensor assignable to the CH 2 scissoring vibration at 1400 cm −1 is found to be not transferable between different molecules in different crystals. However, the amide I Raman tensor of the peptide group is found to remain nearly unchanged on going from a dipeptide crystal to a synthetic polypeptide fiber. The usefulness of such knowledge in determining the orientation of a functional group in a biological system is suggested.

Photo-induced electron transfer reaction between hexamethyldisilane and quinones as studied by a CIDNP technique

Abstract The reaction mechanism of photo-induced electron transfer reactions from hexamethyldisilane to quinones in chloroform solution was studied at room temperature by means of a CIDNP technique. With irradiation, the formation of the corresponding mono- and di-trimethylsilyl hydroquinones and trimethylsilyl chloride was confirmed by GC, GC-MS, and 1 H NMR spectra. The absorptive CIDNP phase of the mono-trimethylsilyl hydroquinone indicates that this reaction precursor is the triplet radical ion pair of the hexamethyldisilane cation radical and quinone anion radical, and that the former radical reacts with the latter prior to the fission of its SiSi bond.

Local Raman tensors in adenosine triphosphoric acid

Abstract A polarized laser (488.0 nm) Raman spectroscopic measurement has been made on a single crystal of a disodium salt of adenosine triphosphoric acid (Na 2 ATP·3H 2 O) by the use of a Raman microscope. The crystal belongs to an orthorhombic system of the space group P 2 1 2 1 2 1 , and has dimensions of 10, 100 and 100 μm along the crystallographic axes a , b and c , respectively. For each Raman band in the 300–1800 cm −1 range, the scattering intensity ratio I bb / I cc of the bb and cc polarization components has been determined. For a few bands, the relative intensities of the bc components were also estimated. To augment the data, the depolarization ratio of each Raman band of ATP has also been determined for its acidic (pH = 2.42) H 2 O and D 2 O solutions. From these experimental results, the shapes and orientations of the Raman scattering tensors which are considered to be localized in the adenine-H + portion and in the phosphate portion of the molecule have been derived.