Synthesis of macromolecular systems via lipase catalyzed biocatalytic reactions: applications and future perspectives

Enzymes, being remarkable catalysts, are capable of accepting a wide range of complex molecules as substrates and catalyze a variety of reactions with a high degree of chemo-, stereo- and regioselectivity in most of the reactions. Biocatalysis can be used in both simple and complex chemical transformations without the need for tedious protection and deprotection chemistry that is very common in traditional organic synthesis. This current review highlights the applicability of one class of biocatalysts viz. ‘‘lipases’’ in synthetic transformations, the resolution of pharmaceutically important small molecules including polyphenols, amides, nucleosides and their precursors, the development of macromolecular systems (and their applications as drug/gene carriers), flame retardants, polymeric antioxidants and nanocrystalline solar cells, etc

Effects of Nanoimprinted Structures on the Performance of Organic Solar Cells

The effect of nanoimprinted structures on the performance of organic bulk heterojunction solar cells was investigated. The nanostructures were formed over the active layer employing the soft lithographic technique. The measured incident photon-to-current efficiency revealed that the nanostructured morphology over the active layer can efficiently enhance both light harvesting and charge carrier collection due to improvement of the absorption of incident light and the buried nanostructured cathode, respectively. The devices prepared with the imprinted nanostructures exhibited significantly higher power conversion efficiencies as compared to those of the control cells

Dual influence of H-bonding on the solid-state second- harmonic generation of a chiral quinonoid compound

A new chiral push-pull quinonoid compound, 7,7-bis(3(R)-hydroxypyrrolidino)-8,8-dicyanoquinodimethane (BHPDQ), has been synthesized. Powder studies indicate an appreciable second harmonic generation (SHG) capability, and crystal structure analysis reveals extensive intermolecular H-bonding in BHPDQ. The influence of H-bonding and molecular chirality on the dipole alignment in the crystal is described. The H-bonds play an unusual role of modifying the molecular structure by producing an enhanced molecular twist in BHPDQ; this in turn affects the molecular hyperpolarizability. Thus we describe a novel instance wherein the powder SHG in a molecular material is determined by the dual influence of intermolecular H-bonding on the crystal structure as well as on the molecular structure and hyperpolarizability. The new dimension that this observation adds to the general theme of molecular materials design is highlighted