Aromatic ring favorable and efficient H-D exchange reaction catalyzed by Pt/C

An effective and applicable Pt/C-catalyzed deuteration method of aromatic rings using D₂O as a deuterium source under hydrogen atmosphere was developed. Five percent Pt/C would lead to quite effective H-D exchange results on the aromatic ring systems. The reaction is general for a variety of aromatic compounds including biologically active compounds.     

High-resolution experimental techniques for cryomechanics—A study of mechanical behavior of materials at 4.2K

High-resolution measurement techniques to quantify minuscule energies (∼0.1 mJ) and microscopic displacements (∼0.01 μm) in a cryomechanics experiment are described. With cryomechanics we study mechanical behavior of materials at 4.2 K. In addition to energy and displacement measurements, we measure acoustic emission and temperature. Preliminary results of tensile and friction tests are presented to demonstrate the key features of our experimental techniques.     

Synthesis and properties of poly(hydroxyurethane)s

Bis(cyclic Carbonate)s 1 were prepared by the reaction of bis(epoxide)s and atmospheric pressure of CO₂ in the presence of sodium iodide and triphenylphosphine as catalysts at 100°C in high yield. Polyaddition of 1 and hexamethylenediamine ( 2a ) or dodecamethylenediamine ( 2b ) in dimethylsulfoxide or N,N-dimethylacetamide (DMAc) at 70 or 100°C for 24 h afforded corresponding poly(hydroxyurethane)s with M?_n 20,000–30,000. When ethylenediamine ( 2c ) or 1,3-propanediamine ( 2d ) was used as a diamine, poly(hydroxyurethane)s with lower molecular weight were obtained. The presence of water, methanol, or ethyl acetate in the solvent had little effect on the M?_n of the polymer obtained, because of the high chemoselectivity of the reaction of the five-membered cyclic carbonate and amine. Polyaddition of bis(cyclic carbonate) bearing ester groups and 2a also afforded the corresponding poly(hydroxyurethane) without aminolysis of the ester groups. Poly(hydroxyurethane) 3 obtained from the bis(cyclic carbonate) derived from bisphenol A was less soluble in organic solvents than model polyurethane 8 having no hydroxy groups obtained from 4,4′-isopropylidenebis(2-hydroxyethoxybenzene) and hexamethylene diisocyanate, and was thermally stable as well as 8.3 easily undertook crosslinking at room temperature by the treatment with hexamethylene diisocyanate or aluminium triisopropoxide in DMAc or tetrahydrofuran. The gel crosslinked by aluminium triisopropoxide regenerated the original polymer at room temperature by treatment with 1.5 equiv of 1.2M HCl in N-methylpyrollidinone for 1 h. © 1993 John Wiley & Sons, Inc.     

Metal-organic thin-film transistor (MOTFT) based on a bis(o-diiminobenzosemiquinonate) nickel(II) complex

The semiconducting film based on bis(o-diiminobenzosemiquinonate) nickel(II) complex showed uniaxial orientation structure along the normal to the substrate and good p-type metal-organic thin-film transistor (MOTFT) character.