Toru Yamanaka

Polymeric Organosilicon Systems: VI. Synthesis and properties of trans-poly[(disilanylene)ethenylene]

Abstract The reaction of trans -bis(chloromethylphenylsilyl)ethene with sodium dispersion in benzene gave trans -poly[1,2-dimethyldiphenyldisilanylene)ethenylene] (II) which is soluble in common organic solvents. Treatment of the film prepared from II with SbF 5 vapor produced a highly conducting film.

Polymeric organosilicon system. VIII: Synthesis of poly[(disilanylene)diethynylene] with highly conducting properties

Abstract The reaction of bis(trimethylsilyl)butadiyne with 2 equiv. of methyllithium, followed by 1,2-dichloro-1,2-dimethyldiphenyl- or 1,2-dichloro-1,2-diethyldimethyldisilane gives poly[(1,2-dimethyldiphenyldisilanylene)diethynylene] (II) or poly[(1,2- diethyldimethyldisilanylene)diethynylene] (III), respectively. Films of II and III become conducting when treated with SbF5 vapor.

Dynamical formation of lipid bilayer vesicles from lipid-coated droplets across a planar monolayer at an oil/water interface

Recently, the transfer method has been shown to be useful for preparing cell-sized phospholipid bilayer vesicles, within which desired substances at desired concentrations can be encapsulated, with a desired asymmetric lipid composition. Here, we investigated the transfer process of water-in-oil (W/O) droplets coated by phospholipid monolayers across an oil/water interface by both experimental observation and theoretical modeling. Real-time experimental observation of the transfer revealed that the transfer process is characterized by three kinetic regimes: a precontact process (approaching regime), an early fast process (entering regime), and a late slow process (relaxation regime). In addition, bigger droplets require much more time to transfer than smaller droplets. We propose a theoretical model to interpret this kinetic process. Our theoretical model reproduces the essential aspects of the transfer kinetics, including its size-dependence.

Photolysis of organopolysilanes. Synthesis and photochemical behavior of Si-silyl substituted polysilacycloalkanes

Four Si-silyl substituted polysilacycloalkanes, 2-trimethylsilyl-1,1,2,3,3-pentamethyl-1,2,3-trisilacyclopentane (1), 2,3-bis(trimethylsilyl)-1,1,2,3,4,4-hexamethyl-1,2,3,4-tetrasilacyclohexane (2), bis(1,1,2,3,3-pentamethyl-1,2,3,-trisilacyclopentyl) (4) and 2-trimethylsilyl-1,1,2,3,3-pentamethyl-1,2,3-trisilacyclohexane (5) were prepared by co-condensation of 1,2-bis(chlorodimethylsilyl)alkanes and 1,1-dichlorotetramethyldisilane with a lithium dispersion in the presence of a catalytic amount of triphenylsilyllithium in THF. The photochemical behavior of compounds 1, 2, 4 and 5 has been investigated in the presence of diethylmethylsilane in cyclohexane. The photolysis of 1 and 5 was found to proceed simultaneously by two different pathways, to give two types of silylene spcies, while compounds 2 and 4 proceeded in a two-step process and expelled a silylene in each step.

Towards constructing synthetic cells: RNA/RNP evolution and cell-free translational systems in giant liposomes

The emerging field of synthetic biology seems to have a great potential to the development of new biotechnologies and the understanding of self-organizing principle in life. Currently, several synthetic biologists aim to understand the evolution of naturally occurring biological systems through a bottom-up approach in contrast to the conventional reductive approach. Several lines of pioneering works have been demonstrated in that behaviors of programmed synthetic networks are predicted in vitro. However, it is crucial to create new molecular parts for (re)constructing synthetic genetic networks in artificial cell-like compartments, such as giant liposomes. We focus on RNA and RNP (ribonucleoprotein) that hold promise as new parts for synthetic biology. They are constructed with molecular design and an experimental evolution technique. So far, designed self-folding RNAs, RNA (RNP) enzymes, and nanoscale RNA architectures have been successfully constructed by utilizing Watson-Crick base-pairs together with specific RNA-RNA or RNA-protein binding motifs of known defined 3D structures. In addition, we also demonstrated that the cell-sized liposomes can be prepared by using phospholipid-coated micro-droplets, which were generated by emulsification or microfluidic techniques. We encapsulated cell-free translation system (PURE SYSTEM) in newly developed liposomes, and successfully monitored protein expression kinetics within individual liposomes in real time. By combining RNA/protein in vitro evolution techniques with giant liposome-based systems, it may be possible to generate artificial protocells with translational regulatory systems.