There has always been a fascination with "impossible" compounds, ones that do not break any rules of chemical bonding or valence but whose structures are unstable and do not exist. This instability can usually be rationalized in terms of chemical or physical restrictions associated with valence electron shells, multiple bonding, oxidation states, catenation, and the inert pair effect. In the pu...

Hierarchically porous silica monoliths with well-defined interconnected macropores and uniform spherical mesopores were spontaneously prepared by combining polymerization-induced phase separation with an epoxide-mediated sol-gel route without any complicated aging and drying and high-temperature heat treatment. The precise control of pore structures can be realized by using propylene oxide (PO)...

Trialkylsiloxy-modified Ta(v) centers on mesoporous silica exhibit excellent selectivity for epoxide formation (>98% after 2 h) in the oxidation of cyclohexene using aqueous H2O2 as the oxidant; the modified catalysts exhibit an increased lifetime, retaining high selectivity after 6 h of reaction (>95% epoxide).

Laser flash photolysis of various organosilicon compounds such as aryl-, vinyl-, and alkynyldisilanes, silacyclobutanes and silacyclobutenes, and alpha-silylketenes and -diazomethanes leads to the formation of reactive silenes which can be detected directly in solution, allowing detailed studies of the kinetics and mechanisms of their reactions with nucleophiles. Over 30 transient silenes have ...

Nanoporous silicas having some periodicity, high surface area (up to 1230 m(2) g(-1)), and pore diameters near the boundary between micro- and mesopores are synthesized using aromatic compounds bearing anionic end-groups as novel structure-directing agents (SDAs) that can facilitate multiple interactions between SDAs, co-SDAs and silica frameworks orthogonally.

Silicon supplementation has been shown to play an important role in skeleton development, however, the potential role that silicon plays in mediating bone formation, and an understanding of where it might localise in the resulting bone tissue remain elusive. An improved understanding of these processes could have important implications for treating pathological mineralisation. A key aspect of d...

the water deficit is the most important limiting non-biological factor to achieve the potential yield of crops. to evaluate the effect of silicon application on yield of millet under drought stress in field an experimental was carried out. treatments were included three irrigation regimes after 60 (non-stress), 90 (moderate stress) and 120 (severe stress) mm evaporation from evaporation pan, cl...

With the increased interest in development of cheap, simple means for indoor air quality monitoring, and specifically in relation to certain well-known pollutant substances with adverse health effects even at very low concentrations, such as different Volatile Organic Compounds (VOCs), this contribution aims at providing an overview of the development status of the silicon carbide field effect ...

unique status among methods for the construction of carbon– carbon bonds. The well-established Stille–Migita–Kosugi coupling of organostannanes and the Suzuki–Miyaura coupling of organoboron compounds are two reactions that, until recently, have been the “gold-standard” among various palladium-catalyzed coupling reactions. Their wide use and extraordinary synthetic utility have provided the imp...

A series of unsymmetrical silicon(IV) phthalocyanines with a permethylated β-cyclodextrin unit and a sugar or a diamino moiety as the axial substituents have been prepared. These compounds are highly photocytotoxic with IC(50) values as low as 21 nM, which is ca. sevenfold lower than those of the symmetrical bis(cyclodextrin) analogue.