Synthesis of Phosphine Oxide-Carboxylic Acid Esters Bearing 9,10-Dihydro-9,10-ethanoanthracene Moiety

A bulky type of phosphine oxide-carboxylic acid bearing 9,10-dihydro-9,10-ethanoanthracene moiety was synthesized by the Diels-Alder reaction of 2-anthryldiphenylphosphine oxide and methyl acrylate, for which the structure was confirmed on the basis of 1 H NMR spectral data to be dimethyl 2-diphenylphosphinoyl-9,10-dihydro-9,10-ethanoanthracene-11,11- and 12,12-dicarboxylates.     

Preparation of three‐dimensional poly(dimethylsiloxane) (PDMS) with movable cross‐linking

A pentamethylcyclotrisiloxane moiety was introduced into cyclic polystyrene (cPSt) and cyclic PDMS (cPDMS) to obtain noncovalent cross‐linking agents, D₃‐cPSt and D₃‐cPDMS, respectively. Anionic ring‐opening polymerization of octamethylcyclotetrasiloxane (D₄) in nitrobenzene was carried out in the presence of D₃‐cPSt to obtain a cloudy white PDMS gel as a precipitation. On the other hand, bulk copolymerization of D₃‐cPDMS with D₄ proceeded in a homogeneous state to give a colorless transparent PDMS gel in high yield. The formation of mechanically linked PDMS with movable cross‐linking was indicated by control experiment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5882–5890, 2009     

Heterotactic‐specific radical polymerization of N‐isopropylacrylamide and phase transition behavior of aqueous solution of heterotactic poly(N‐isopropylacrylamide)

Radical polymerization of N‐isopropylacrylamide (NIPAAm) in toluene at low temperatures, in the presence of fluorinated‐alcohols, produced heterotactic polymer comprising an alternating sequence of meso and racemo dyads. The heterotacticity reached 70% in triads when polymerization was carried out at ?40 °C using nonafluoro‐tert‐butanol as the added alcohol. NMR analysis revealed that formation of a 1:1 complex of NIPAAm and fluorinated‐alcohol through C?O···H? O hydrogen bonding induces the heterotactic specificity. A mechanism for the heterotactic‐specific polymerization is proposed. Examination of the phase transition behavior of aqueous solutions of heterotactic poly(NIPAAm) revealed that the hysteresis of the phase transition between the heating and cooling cycles depended on the average length of meso dyads in poly(NIPAAm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2539–2550, 2009     

Highly polarized very cold neutrons through a permanent magnet quadrupole

We obtained highly polarized very cold neutrons through a quadrupole magnet with a large aperture. When neutrons go through a quadrupole magnet, parallel-spin neutrons are attracted to the magnet axis and anti-parallel-spin neutrons are repelled off the axis. Therefore, the neutrons through a sufficiently long quadrupole magnet have completely parallel-spin. At the downstream of the quadrupole magnet, we placed another quadrupole magnet to divide neutrons into two regions depending on their spin directions. We obtained the neutron polarization from the integrated count of the two regions and found it was 99.88±0.09 (stat.)±0.05 (syst.)%.     

Proton Diffusion in High Pressure Ice

We have developed a spectroscopic method for measuring proton diffusion process in ice at high pressure and temperature using a diamond anvil cell (DAC). It enables us to determine the self diffusion constant of proton (deuteron) from infrared reflection spectra collected as a function of time for a H 2 O/D 2 O ice bilayer prepared and pressurized in the DAC. A preliminary experiment for ice VII at 14 GPa and 400 K provided a diffusion constant D=1.2\times1^{-15} m 2 /s. This was the first measurement of the proton diffusion in pure ice.     

A novel attractive interaction in the Diels–Alder reaction of N-protected pyrroles with allene-1,3-dicarboxylates

The endo/exo selectivities of Diels–Alder reactions of N-protected pyrroles with allene-1,3-dicarboxylates were studied under Lewis acid assisted and thermal reaction conditions. A novel attractive effect between the N-protective carbonyl group of pyrrole and the ester group of allene-1,3-dicarboxylates operates to control the selectivity in the above Diels–Alder reaction. This new attractive effect to give the exo adduct is more effective than the Alder orbital effect.