Suzuki-Miyaura Cross-Coupling Reaction Using Palladium Catalysts Supported on Phosphine Periodic Mesoporous Organosilica.

Phosphine periodic mesoporous organosilicas (R-P-PMO-TMS: R=Ph, tBu), which possess electron-donating alkyl substituents on the phosphorus atom, were synthesized using bifunctional compounds with alkoxysilyl- and phosphino groups, bis[3-(triethoxysilyl)propyl]phenylphosphine borane (1 a) and bis[3-(triethoxysilyl)propyl]-tert-butylphosphine borane (1 b). Immobilization of Pd(0) species was performed to give R-P-Pd-PMO-TMS: R=Ph (2 a), tBu (3 a), respectively. The Pd(0) immobilized 2 a and 3 a were applicable as catalysts for Suzuki-Miyaura cross-coupling reactions of aryl chlorides with phenylboronic acid. It was revealed that 3 a bearing more electron-donating tBu groups exhibited higher catalytic activity. Various functional groups including both electron withdrawing and donating substituents were compatible in the system. The recyclability of 3 a was examined to support its moderate utility for the recycle use.

Singularity response reveals entrainment properties in mammalian circadian clock.

Entrainment is characterized by phase response curves (PRCs), which provide a summary of responses to perturbations at each circadian phase. The synchronization of mammalian circadian clocks is accomplished through the receipt of a variety of inputs from both internal and external time cues. A comprehensive comparison of PRCs for various stimuli in each tissue is required. Herein, we demonstrate that PRCs in mammalian cells can be characterized using a recently developed estimation method based on singularity response (SR), which represents the response of desynchronized cellular clocks. We confirmed that PRCs can be reconstructed using single SR measurements and quantified response properties for various stimuli in several cell lines. SR analysis reveals that the phase and amplitude after resetting are distinguishable among stimuli. SRs in tissue slice cultures reveal tissue-specific entrainment properties. These results demonstrate that SRs can be employed to unveil entrainment mechanisms with diverse stimuli in multiscale mammalian clocks.

Real time monitoring of cold Ca2+ dependent transcription and its modulation by NCX inhibitors.

Real-time monitoring of cellular temperature responses is an important technique in thermal biology and drug development. Recent study identified that Na+/Ca2+ exchanger (NCX)-dependent Ca2+ influx transduces cold signals to circadian clock in mammalian cultured cells. The finding raised an idea that cellular responses to the cold signals can be analyzed by monitoring of clock gene expression. We found that Per1 and Per2 were up-regulated after culture at 27 °C compared to 37 °C in Rat-1 fibroblasts. In order to monitor cold-Ca2+-dependent transcription in living cells, we developed a luciferase-based real-time reporting system by using Per1 promoter, Per2 promoter, Ca2+/cAMP-response elements (CRE) or NFAT-binding elements. We found that benzyloxyphenyl NCX inhibitor KB-R7943 and SN-6, but not SEA-0400 or YM-244769 inhibited the cold induction of Per2. Our study established a real-time monitoring system for cold Ca2+ signaling which can be applied to evaluation of drugs.

Heterolytic cleavage of a Si-H bond by a metal-ligand cooperation of a cationic iridium amido complex and hydrosilylation of aldehydes.

Heterolytic cleavage of a Si-H bond was achieved mediated by a metal-ligand cooperation of a cationic iridium amido complex. The reaction was applied to the catalytic hydrosilylation of benzaldehyde and its derivatives, affording the corresponding hydrosilylated products in moderate to good yields.

Highly Active NaTaO3 -Based Photocatalysts for CO2 Reduction to Form CO Using Water as the Electron Donor.

Doped NaTaO3 (NaTaO3 :A, where A=Mg, Ca, Sr, Ba, or La) has arisen as a highly active photocatalyst for CO2 reduction to simultaneously form CO, H2 , and O2 using water as the electron donor when used with an Ag cocatalyst, under UV irradiation, and with 1 atm (0.1 MPa) of CO2 . The ratio of the number of reacted electrons/holes was almost unity, indicating that water was consumed as the electron donor. A liquid-phase reduction method for loading of the Ag cocatalyst was superior to photodeposition and impregnation methods. The Ag cocatalyst-loaded NaTaO3 :Ba was the most active photocatalyst in water with no required additives. The addition of bases, such as hydrogencarbonate, was effective to enhance the CO formation for Mg-, Ca-, Sr-, Ba-, and La-doped NaTaO3 photocatalysts with an Ag cocatalyst. Ca- and Sr-doped NaTaO3 photocatalysts showed especially high activity along with the Ba-doped photocatalyst in the aqueous NaHCO3 solution. The selectivity for the CO formation [CO/(CO+H2 )] on Ca-, Sr-, and Ba-doped NaTaO3 photocatalysts with Ag cocatalyst reached around 90 %.

Photocatalytic reduction of carbon dioxide over Ag cocatalyst-loaded ALa4Ti4O15 (A = Ca, Sr, and Ba) using water as a reducing reagent.

Ag cocatalyst-loaded ALa(4)Ti(4)O(15) (A = Ca, Sr, and Ba) photocatalysts with 3.79-3.85 eV of band gaps and layered perovskite structures showed activities for CO(2) reduction to form CO and HCOOH by bubbling CO(2) gas into the aqueous suspension of the photocatalyst powder without any sacrificial reagents. Ag cocatalyst-loaded BaLa(4)Ti(4)O(15) was the most active photocatalyst. A liquid-phase chemical reduction method was better than impregnation and in situ photodeposition methods for the loading of the Ag cocatalyst. The Ag cocatalyst prepared by the liquid-phase chemical reduction method was loaded as fine particles with the size smaller than 10 nm on the edge of the BaLa(4)Ti(4)O(15) photocatalyst powder with a plate shape during the CO(2) reduction. CO was the main reduction product rather than H(2) even in an aqueous medium on the optimized Ag/BaLa(4)Ti(4)O(15) photocatalyst. Evolution of O(2) in a stoichiometric ratio (H(2)+CO:O(2) = 2:1 in a molar ratio) indicated that water was consumed as a reducing reagent (an electron donor) for the CO(2) reduction. Thus, an uphill reaction of CO(2) reduction accompanied with water oxidation was achieved using the Ag/BaLa(4)Ti(4)O(15) photocatalyst.