Alleviation of photoinduced damage in GdxY1-xCa4O(BO3)3 at elevated crystal temperature for noncritically phase-matched 355-nm generation

We developed a Gd(x)Y(1-x)Ca(4)O(BO(3))(3) (GdYCOB) crystal for control of optical birefringence. GdYCOB crystals were successfully used to generate noncritical phase-matched (NCPM) second and third harmonics of 1064-nm lights. However, we observed degradation of third-harmonic-generation (THG) output power and distortion of the beam pattern as a result of photoinduced damage and thermal dephasing. The photoinduced damage was classified into two types. One was gray-track and the other was photorefractive damage. It seems that these types of damage were similar to the types of damage that occurred with KTiOPO(4) and LiNbO(3) crystals. We tried to circumvent this problem by crystal heating. Photoinduced damage of GdYCOB was overcome by elevation of the crystal temperature, and NCPM THG (355-nm) output power from heated GdYCOB increased to 9 mW (62.5 kHz).     

A search for Na atom in CsI:Na crystal

The presence of a Na atom in CsI: Na after X-ray irradiation is searched by ESR (35 GHz microwave) detected through the magnetic circular dichroism of a related optical absorption band. The results are discussed with the model of Na atom in the crystal where either 3s or 3 p_z orbit is the ground state depending on its site.     

Stereo- and regio-selective conversion of 1-trimethylsilylallylic alcohols into the silyl enol ethers catalyzed by butyllithium

(Z)-Silyl enol ethers can be prepared selectively with complete regio-specificity by treating 1-trimethylsilylallylic alcohols with a catalytic amount of butyllithium.     

Palladium complex-catalyzed carbonylation of organic halides in the presence of cyclic ethers: Halohydrin ester synthesis

Cyclic ethers were cleaved by palladium complex-catalyzed carbonylation of organic halides to give halohydrin esters.     

Palladium(II)-catalyzed double carbonylation of organic halides in the presence of amines: α-Ketoamide synthesis

Aryl, hetero-aryl, and vinylic halides react with carbon monoxide (40 atm pressure or less) and a secondary amine at 60–100°C in the presence of a catalytic amount of palladium compound to form α-ketoamides, in addition to simple amides as by-products. When a primary amine was used in place of a secondary one, an imine of the α-ketoamide was readily obtained.     

Preparation and synthetic use of the zerovalent nickel complex by electrochemical reduction

The generation of Ni(PPh₃)₄ by electrochemical reduction was carried out in a divided cell containing NiCl₂(PPh₃)₄, PPh₃ and n-Bu₄NBr in DMF with a lead plate as cathode and a platinum plate as anode under the stream of argon at 60°. Using this Ni(PPh₃)₄, biphenyls and the heterocyclic compounds were synthesized in fairly good yields.     

Investigation of stability of (Ge,Sn)-(S,or Se)42 cluster vibrational spectra

The insistent two mode type behavior of the A₁ and high frequency F₂ bands in the tin contained glasses is reproduced by our vibrational calculations based on the outrigger-raft with some modifications. High pressure Raman spectra suggest an instability of the tin tetrahedral bonding. Comparative study of glassy and crystalline Ge(Se, or S)₂ by high pressure Raman scattering gives important informations about the strain field and the topological order in the glasses.