Kozo Kozawa

Novel organic SHG materials

Abstract Of 140 newly synthesized chalcone-analogous materials, 56 specimens were observed to be efficient for nonlinear optical second harmonic generation (SHG). The SHG efficiency of 3-(4-chlorophenyl)-1-(3-pyridyl)-2-propen-1-one is discussed on the basis of crystal structure and MO calculation. In this crystal, molecules arrange themselves almost ideal manner for SHG.

Preparation of liposomes containing Ceramide 3 and their membrane characteristics.

Liposomes composed of Ceramide 3, [2S,3S,4R-2-stearoylamide-1,3,4-octadecanetriol], and L-alpha-dipalmitoylphosphatidylcholine (DPPC) were prepared by varying the amount of Ceramide 3, and the effects of Ceramide 3 on the liposome formation, particle size, dispersibility, microviscosity and phase transition temperature were examined by means of a microscopy, a dynamic light scattering method, a fluorescence polarization method, a differential scanning calorimetry (DSC) and so on. All the DPPC was able to contribute to the formation of liposomes up to 0.130 mol fraction of Ceramide 3. The particle size of liposomes was almost unaffected by the addition of Ceramide 3. The dispersibility of liposomes containing Ceramide 3 was maintained for at least 15 days. The microviscosity of liposomal bilayer membranes in the liquid crystalline state was increased with increasing the mole fraction of Ceramide 3, while that in the gel state was independent of the mole fraction of Ceramide 3. The phase transition temperature from gel to liquid crystalline states of DPPC bilayer membranes was shifted upwards with the addition of Ceramide 3, indicating a cooperative interaction between DPPC and Ceramide 3 molecules. However, a sharp DSC peak became broad and split at higher mole fractions of Ceramide 3, suggesting a phase separation in the mixed DPPC/Ceramide 3 liposomal bilayer membranes. These phenomena were suggested to be related to the previously observed fact for the mixed DPPC/Ceramide 3 monolayers that Ceramide 3 interacts with DPPC in the liquid-expanded phase with consequent phase separation accompanied with domain formation.

Atomic force microscopic study on the surface properties of phospholipid monolayers containing Ceramide 3

Abstract The interactions between l -α-dipalmitoylphosphatidylcholine (DPPC) and 2 S ,3 S ,4 R -2-stearoylamide-1,3,4-octadecanetriol (Ceramide 3) in the mixed monolayers were investigated by using a surface pressure measurement and an atomic force microscopy (AFM). Mixed DPPC/Ceramide 3 monolayers were deposited on mica using the Langmuir–Blodgett (LB) technique for AFM. In the case of DPPC alone system, the phase transition from the liquid-expanded film to the liquid-condensed film was observed at 17 mN m −1 of surface pressure. Whereas in the case of Ceramide 3 alone system, no phase transition and only the liquid-condensed film were observed. In the mixed DPPC/Ceramide 3 systems, the average area per molecule in the liquid-condensed film was almost independent of the mole fraction of Ceramide 3, while that in the liquid-expanded film decreased with increasing the mole fraction of Ceramide 3. The observed negative deviation of the average area per molecule from the ideality relation indicated an attractive interaction between Ceramide 3 and DPPC in the liquid-expanded films, suggesting the higher packing density in the mixed DPPC/Ceramide 3 monolayers as compared with the pure components monolayers. The AFM images for the mixed DPPC/Ceramide 3 monolayers deposited at 10 mN m −1 of surface pressure on mica indicated elliptical domains, while those deposited at 30 mN m −1 of surface pressure indicated no domains. Ceramide 3 is likely to interact with DPPC in the liquid-expanded phase and consequently bring about phase separation.

Hydrogen rearrangements in CsHSeO4 accompanied with both the phase transition and domain-boundary-movement

Hydrogen rearrangements accompanied with the movement of domain boundaries in CsHSeO 4 below the ferroelastic phase transition temperature ( T c =128°C) and possible motional states of hydrogens above T c were studied based on the crystal structure obtained in the X-ray re-examination at room temperature and twinning conditions for ferroelastic domains observed below T c . The crystal was confirmed to be monoclinic with the space group P 2 1 / c and to have a superlattice structure below T c , while it is tetragonal with the space group I 4 1 / amd above T c . It was deduced by taking account of symmetry change from P 2 1 / c to I 4 1 / amd and twinning conditions that the hydrogen bonds in CsHSeO 4 above T c are broken instantaneously and the hydrogens are hopping among the 16-fold (f) equivalent positions, leading to so called three-dimensional superionic conductivity of hydrogens above T c .

Structural study of chalcone derivatives

Abstract Crystal structures of several SHG-active chalcone derivatives were determined by X-ray analysis. The phase-matching direction of a 1-(3-thienyl)-3-(4-chlorophenyl)-2-propen-1-one crystal is discussed by relating to its molecular packing in the crystal.

Organometallic compounds. XXXIX: Synthesis and X-ray crystal structure of [4][3][4][3](1,2,3,4)ferrocenophane

Abstract [4][3][4][3](l,2,3,4)FeiTocenophane (I) and some related tetrabridgedferrocenophanes have been synthesized via cyclization of 2-[4][4][3](l,3,4)ferroce acid with polyphosphate ester (PPE). Treatment of 5- [4][4][3](l,3,4)ferrocenophanepropanoic acid with PPE or polyphosphoric acid does not give an additionally bridged compound but a bridge-rearrangement product containing two homoannular rings. The crystal structure of I has been determined by X-ray diffraction. Compound I crystallizes in the monoclinic system, space groupP21/a with unit cell parametersa 17.490(4),b 8.489(1),c 12.157(2) «, β 101.51(1)°, andZ = 4. The two cyclopentadienyl (Cp) rings are in an eclipsed conformation and almost parallel to each other (dihedral angle, 1.1°). The bond lengths and angles in the Cp rings and methylene chains are normal but the distances between the Cp ring and the iron atom are unusually short (1.589 and 1.591 «) in comparison with multibridged ferrocenophanes containing tetramethylene chains.

Synthesis and Properties of Terrylenedicarboximide Derivatives

Terrylenedicarboximide derivatives were prepared by the coupling of N-alkyl-9-tributylstannylperylene-3,4-dicarboximides with 4-bromo-1,8-naphthalimide derivative and the following ring closure reaction. Spectral properties in solution or in the solid state and the thermal stability of these derivatives were investigated.

Structure and properties of a new acceptor molecule including boron atoms : 5,10-dimethyl-5,10-dihydroboranthrene

Abstract A new organic acceptor, 5,10-dimethyl-5,10-dihydroboranthrene (BMBT), was prepared and its molecular structure was determined by X-ray analysis. Redox potential suggests that BMBT is a weak acceptor. A charge transfer between BMBT and TTF was confirmed by the complex formation.

Organometallic compounds : XXXVI. X-ray crystal structure of [4][3][4](1,2,3)Ferrocenophane

Abstract The crystal and molecular structure of [4][3][4](1,2,3)ferrocenophane, a ferrocenophane bridged at three neighbouring positions, has been determined by X-ray diffraction. The compound crystallizes in the orthorhombic system, space group Pcab with unit cell dimensions a  15.973(2), b  17.007(2), c  11.648(1) A, and Z  8. The two cyclopentadienyl rings are nearly eclipsed and the dihedral angle between the two rings is 10.4°. The bond lengths and angles in the cyclopentadienyl rings and methylene chains have been found in almost normal ranges in comparison with multibridged ferrocenophanes already reported.

Crystal structure and mixed alkali effect of (K+, Cs+)-β-ferrite

Abstract Crystal structure determination has been accomplished for (K + 0.3 , Cs + 0.7 )-β-ferrite with β-alumina structure to investigate the mixed alkali effect in ionic conduction. According to the structure of conduction plane, BR sites were occupied by cesium ions and mO sites were occupied by potassium ions. It was concluded that blocking effect of cesium ions in BR sites dominate the mixed alkali effect in this ferrite.