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Thermally stable, solid-state luminescent organic materials are highly desired for the development of practical applications. Herein we synthesized new gold(I) complexes with N -heterocyclic carbene ligands, which have the ability to form strong metal-organic bond. Consequently, their thermochemical stability is enhanced at temperatures around 300 °C. Precise design of the molecular structure of the ligands, with a focus on ensuring low steric hindrance around Au atoms in order to limit disturbances to Au/Au interactions, provided a complex with a densely packed crystal with a shorter intermolecular Au–Au distance (3.17 A) than the typical distance. In the solid state, this complex exhibited strong aurophilic interactions, which generated intense phosphorescence even in air at room temperature (quantum yield=16%) in spite of absence of any phosphorescence in solution. This behavior is characteristic for solid-state luminescence referred to as aggregation-controlled emission. Furthermore, the gold(I) complex displays capacity for mechano- and vapo-chromism—that is, the ability to change color reversibly in response to the application of external stimuli. We believe that the proposed design framework, which involves controlling thermal stability and luminescence property separately, provides a new opportunity for the development of practical applications using solid-state luminescent organic molecules.

Gold(I) complexes are some of the most attractive materials for generating aggregation-induced emission (AIE), enabling the realization of novel light-emitting applications such as chemo-sensors, bio-sensors, cell imaging, and organic light-emitting diodes (OLEDs). In this study, we propose a rational design of luminescent gold complexes to achieve both high thermochemical stability and intense room temperature phosphorescence, which are desirable features in practical luminescent applications. Here, a series of gold(I) complexes with ligands of N-heterocyclic carbene (NHC) derivatives and/or acetylide were synthesized. Detailed characterization revealed that the incorporation of NHC ligands could increase the molecular thermochemical stability, as the decomposition temperature was increased to ~300 &deg, C. We demonstrate that incorporation of both NHC and acetylide ligands enables us to generate gold(I) complexes exhibiting both high thermochemical stability and high room-temperature phosphorescence quantum yield (&gt, 40%) under ambient conditions. Furthermore, we modified the length of alkoxy chains at ligands, and succeeded in synthesizing a liquid crystalline gold(I) complex while maintaining the relatively high thermochemical stability and quantum yield.

In this paper, we researched the experimental conditions of the method regulated by Japanese Industrial Standard for rotational accuracy of Rolling Bearings. We produced a measuring apparatus based on JIS and measured radial accuracy of angular contact ball bearing in various conditions. The results are summarized as follows : (1) The evaluation method in JIS had large dispersion. (2) The influence of the measuring conditions on radial run-out was very big. It was necessary to unify the measuring conditions in order to evaluate the radial accuracy of rolling bearings.

In this paper, we researched the NRRO of an angular contact ball bearing for machine tools. At first, we developed a new apparatus for measuring rotational accuracy of rolling bearings. It was cleared the following results by measuring the radial NRRO used this apparatus. (1) The NRRO of cage rotation increased with rotational speed. (2) The influence of the shape error of inner and outer ring on NRRO was small. (3) The influence of the shape error and the diameter difference of balls were very big.

Optical resolution of (1RS, 3SR)-(1) and (1RS, 3RS)-(2) dithiirane 1-oxides was achieved by HPLC equipped with a chiral column to give 1a and 1b and 2a and 2b, respectively. X-ray analyses proved absolute configurations of 1a and 1b to be (1R, 3S) and (1S, 3R), while those of 2a and 2b were determined to be (1R, 3R) and (1S, 3S), respectively, since 2a and 2b isomerized stereospecifically to 1b and 1a, respectively. Enantiomeric dithiirane 1-oxides 1a and 1b reacemized to each other whereas 2a and 2b did not. To the racemization (oxygen migration) is proposed a mechanism involving homolysis of the S(O) S bond at the initial step followed by a ring closure giving a 1,2,4-oxathietane intermediate. Isomerization between 1 and 2 was inhibited by a radical scavenger, DPPH.

The reaction of the 6-exo-oxide of 2,2,4,4-tetramethyl-1,5-diphenyl-6,7-dithiabicyclo[3.1.1]heptane (2) with 2KHSO5·KHSO4·K2SO4 gave the first isolable dithiirane oxide, (1RS, 3SR)-3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane 1-oxide (1), while the 6-endo-oxide of 2 gave both 1 and its (1RS, 3RS)-isomer 10. Under similar reaction conditions, 2 yielded the first isolable, unoxidized dithiirane, 3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane (3). The dithiirane 3 was also obtained by treatment of 2 with NaOCl–NaClO4. The X-ray structure analyses were performed for 1, 3, and 10. Treatment of unsymmetrical 8,8-dimethyl-1,9-diphenyl-10,11-dithiatricyclo[7.1.1.02,7]undeca-2,4,6-triene with NaOCl–NaClO4gave 3-[1-(o-benzoylphenyl)-1-methylethyl]-3-phenyldithiirane selectively in good yield. However, 1,3-dithietanes, prepared from adamantane-2-thiones, failed to give the corresponding dithiiranes by treatment with 2KHSO5·KHSO4·K2SO4 or NaOCl–NaClO4. The dithiirane 3 thermally isom...

Visible (VIS) absorption spectra were measured for the dispersion system consisting of α-Al 2 O 3 powder and CoCl 2 aqueous solution. The VIS spectra of the paste differed from that of the bulk solution. The absorption bands of the Co(II) octahedral complex were shifted and broadened, whereas the intensity of the Co(II) tetrahedral complex ([CoCl 4 2- ) at ca. 15,000 cm -1 increased with the solid content and the specific surface area of α-Al 2 O 3 powder. The intensity ratio of the absorption bands of the tetrahedral complex to the octahedral complex, R 4/6 , correlated with the apparent average thickness of the impregnating liquid layer. The relationship between the VIS spectra and electrical conductivity was also examined. The activation energies for the electrical conductivity, Δ E a , and R 4/6 were correlated linearly. It is concluded that variation of the VIS spectra of the paste sample was caused by the structural change of the dissolved ionic species in the liquid layer which is ca. 20-30 nm thick near the solid surface.

The reaction of the 6-exo-oxide of 2,2,4,4-tetramethyl-1,5-diphenyl-6,7-dithiabicyclo[3.1.1]heptane (2) with 2KHSO5·KHSO4·K2SO4 gave the first isolable dithiirane oxide, (1RS, 3SR)-3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane 1-oxide (1), while the 6-endo-oxide of 2 gave both 1 and its (1RS, 3RS)-isomer 10. Under similar reaction conditions, 2 yielded the first isolable, unoxidized dithiirane, 3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane (3). The dithiirane 3 was also obtained by treatment of 2 with NaOCl–NaClO4. The X-ray structure analyses were performed for 1, 3, and 10. Treatment of unsymmetrical 8,8-dimethyl-1,9-diphenyl-10,11-dithiatricyclo[7.1.1.02,7]undeca-2,4,6-triene with NaOCl–NaClO4gave 3-[1-(o-benzoylphenyl)-1-methylethyl]-3-phenyldithiirane selectively in good yield. However, 1,3-dithietanes, prepared from adamantane-2-thiones, failed to give the corresponding dithiiranes by treatment with 2KHSO5·KHSO4·K2SO4 or NaOCl–NaClO4. The dithiirane 3 thermally isom...

Optical resolution of (1RS, 3SR)-(1) and (1RS, 3RS)-(2) dithiirane 1-oxides was achieved by HPLC equipped with a chiral column to give 1a and 1b and 2a and 2b, respectively. X-ray analyses proved absolute configurations of 1a and 1b to be (1R, 3S) and (1S, 3R), while those of 2a and 2b were determined to be (1R, 3R) and (1S, 3S), respectively, since 2a and 2b isomerized stereospecifically to 1b and 1a, respectively. Enantiomeric dithiirane 1-oxides 1a and 1b reacemized to each other whereas 2a and 2b did not. To the racemization (oxygen migration) is proposed a mechanism involving homolysis of the S(O) S bond at the initial step followed by a ring closure giving a 1,2,4-oxathietane intermediate. Isomerization between 1 and 2 was inhibited by a radical scavenger, DPPH.

2-Methoxyallenylmethylsilane reacts with alkenes and alkynes in a [2+2] cycloaddition mode to give cyclobutanes and cyclobutenes, respectively. Cycloadducts are converted to di-exo-methylene compounds through 1,2-elimination of the methoxy and silyl groups. These di-exo-methylenecyclobutanes and -cyclobutenes react with alkenes and 1,3-dienes to afford fused bi- and tricyclic compounds.

The electrical conductivity and its temperature dependence were investigated for α-Al 2 O 3 powder/CaCl 2 aqueous solution coexisting system by ac impedance method. The electrical conductivity of the paste unusually decreased with an increase of the volume fraction of the solid phase. The temperature dependence of the electrical conductivity of log a s. 1/T showed a good linear relationship for the system containing the dilute solution as a liquid phase. The activation energy for the electrical conductivity, ΔE a , was determined from the temperature dependence