[structure: see text] A bispyrrol-2-yl-2,5-diamidopyrrole has been synthesized and shown to have a significantly higher affinity for oxo-anions than previous generation 2,5-diamidopyrroles. 相似文献
Two microscopic transition theorems are given for the probability of nonequilibrium work performed on a subsystem of a thermal reservoir along the trajectory in phase space of the subsystem. The resultant transition probability is applied to the case of heat flow down an applied temperature gradient. A combined molecular dynamics and Monte Carlo algorithm is given for such a nonequilibrium steady state. Results obtained for the thermal conductivity are in good agreement with previous Green-Kubo and nonequilibrium molecular dynamics results. 相似文献
We report a new method for the direct labeling and visualization of crystalline cellulose using quantum dots (QDs) directed
by carbohydrate-binding modules (CBMs). Two type-I (surface binding) CBMs belonging to families 2 and 3a were cloned and expressed
with dual histidine tags at the N- and C-termini. Semiconductor (CdSe)ZnS QDs were used to label these CBMs following their binding to Valonia cellulose crystals. Using this approach, we demonstrated that QDs are linearly arrayed on cellulose, which implies that these
CBMs specifically bind to a planar face of cellulose. Direct imaging has further shown that different sizes (colors) of QDs
can be used to label CBMs bound to cellulose. Furthermore, the binding density of QDs arrayed on cellulose was modified predictably
by selecting from various combinations of CBMs and QDs of known dimensions. This approach should be useful for labeling and
imaging cellulose-containing materials precisely at the molecular scale, thereby supporting studies of the molecular mechanisms
of lignocellulose conversion for biofuels production. 相似文献
Metal‐free triazole turns : 1,5‐Disubstituted peptidyl triazoles are obtained regioselectively from the 1,3‐dipolar cycloaddition of peptidyl phosphoranes and azides. Peptide turns are thus formed that contain a conformationally locked cis peptide bond. Being regioselective and free of heavy metals, this reaction may find broad application in chemical biology and medicinal chemistry.
A new approach to the enantiocontrolled synthesis of α-amino ketone derivatives is disclosed by employing a decarboxylative acylation strategy. Thus, when an acyl chloride and an α-amido-containing redox-active ester are exposed to a nickel catalyst, chiral ligand, and metal reductant, α-amido ketones are produced in good yield and high ee. The reaction exhibits broad substrate scope, can be easily scaled up, and is applied to dramatically simplify the synthesis of several known structures. 相似文献
A mild, scalable (kg) metal-free electrochemical decarboxylation of alkyl carboxylic acids to olefins is disclosed. Numerous applications are presented wherein this transformation can simplify alkene synthesis and provide alternative synthetic access to valuable olefins from simple carboxylic acid feedstocks. This robust method relies on alternating polarity to maintain the quality of the electrode surface and local pH, providing a deeper understanding of the Hofer-Moest process with unprecedented chemoselectivity. 相似文献