PLA emerged as a promising polymer because of its property as a compostable, biodegradable thermoplastic made from renewable sources. PLA can be polymerized from monomers (Lactide or Lactic acid) obtained by fermentation processes from renewable sources such as corn starch or sugarcane. For PLA synthesis, ring opening polymerization (ROP) of Lactide monomer is one of the preferred methods. In t...

ZnO nanowire nucleation mechanism and initial stages of nanowire growth using the carbothermal reduction technique are studied confirming the involvement of the catalyst at the tip in the growth process. Role of the Au catalyst is further confirmed when the tapering observed in the nanowires can be explained by the change in the shape of the catalyst causing a variation of the contact area at t...

A new urea-containing metal-organic framework (MOF) was synthesized to act as a heterogeneous catalyst. Ureas are well-known for self-recognition and aggregation behavior, resulting in loss of catalytic competency. The catalyst spatial isolation achievable in a porous MOF environment suggests a potentially general solution. The combination of a symmetrical urea tetracarboxylate strut, 4,4'-bipy...

We report that micromolar concentrations of lanthanide ions can be required cofactors for DNA-hydrolyzing deoxyribozymes. Previous work identified deoxyribozymes that simultaneously require both Zn(2+) and Mn(2+) to achieve DNA-catalyzed DNA hydrolysis (10(12) rate enhancement); a mutant of one such DNA catalyst requires only Zn(2+). Here we show that in vitro selection in the presence of 10 µM...

Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of com...

We report that micromolar concentrations of lanthanide ions can be required cofactors for DNAhydrolyzing deoxyribozymes. Previous work identified deoxyribozymes that simultaneously require both Zn and Mn to achieve DNA-catalyzed DNA hydrolysis (10 rate enhancement); a mutant of one such DNA catalyst requires only Zn. Here we show that in vitro selection in the presence of 10 mM lanthanide ion (...

Mononuclear complexes between Zn(2+) and the following four macrocycles were prepared: 1,4,7,10-tetraazacyclododecane (1), 1-oxa-4,7,10-triazacyclododecane (2), 1,5,9-triazacyclododecane (3) and 1-hydroxyethyl-1,4,7-triazacyclononane (4). The pH rate profiles of values of the observed second-order rate constant log (k(Zn))(app) for Zn(X)(OH(2))-catalyzed cleavage (X = 1, 2, 3 and 4) of 2-hydrox...

Nanostructured Cu(x)Zn(1-x)Al(2)O(4) with a Cu:Zn ratio of ¼:¾ has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al(2)O(3)-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m(2) g(-1)). Cu nanoparticles of an average size of 3.3 nm can be formed by reduct...

metalloporphirins; cu(tpp), mn(tpp)cl, co(tpp), fe(tpp)cl, zn(tpp) and mn(obp)cl catalyze region and chemoselective silylation of hydroxyl groups with hmds. fe(tpp)cl is the most effective catalyst and silylation occurs immediately in its presence at room temperature.