A Facile and Convenient Synthesis of some Novel Hydrazones, Schiff’s Base and Pyrazoles Incorporating Thieno[2,3-b]thiophenes

A facile and convenient synthesis of some novel hydrazones, schiff’s base and pyrazoles from thieno[2,3-b]thiophene derivatives 1 have been achieved in high yields assisted by microwave and classical methods. The structures of all the title compounds have been elucidated by elemental analysis, IR, MS, 1H-NMR and 13C-NMR. Generally, these findings represent a new class of sulfur and nitrogen moieties that should also be of interest as new materials

Macromolecular Scaffolding: The Relationship Between Nanoscale Architecture and Function in Multichromophoric Arrays for Organic Electronics

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Micellar Nanoreactors

As clearly described in the series of illustrative examples reported above, the use of micellar environments in catalysis is not just a soapy version of homogeneous catalysis.71 Micelles behave much more as nanoreactors characterized by unique features with all the extra advantages intrinsic in the use of water as solvent. Micellar catalysis has been demonstrated to be suitable to almost all classes of chemical transformations, in particular for a wide range of reactions promoted by metal complexes or organometallic species, also with impressive examples in asymmetric catalysis. The great advantage of using catalysts already developed for use in organic media without the need of ligand modifications to make the catalyst compatible with water, together with the self-assembling nature of surfactants, is the key factor for the success of micellar catalysis with metal species. The surfactant is not just a spectator as usually the solvent is believed to be, rather it directs the overall system. A critical balance between catalyst, substrate, and surfactant properties must be analyzed in detail in order to ensure high yield, selectivity, and recyclability. It can be predicted that, thanks to their generally low cost, surfactants will soon find some applications in large-scale synthetic methods suitable for industrial applications

Synthesis and characterization of poly(amino acid methacrylate)-stabilized diblock copolymer nano-objects

Amino acids constitute one of Nature's most important building blocks. Their remarkably diverse properties (hydrophobic/hydrophilic character, charge density, chirality, reversible cross-linking etc.) dictate the structure and function of proteins. The synthesis of artificial peptides and proteins comprising main chain amino acids is of particular importance for nanomedicine. However, synthetic polymers bearing amino acid side-chains are more readily prepared and may offer desirable properties for various biomedical applications. Herein we describe an efficient route for the synthesis of poly(amino acid methacrylate)stabilized diblock copolymer nano-objects. First, either cysteine or glutathione is reacted with a commercially available methacrylate-acrylate adduct to produce the corresponding amino acid-based methacrylic monomer (CysMA or GSHMA). Well-defined water-soluble macromolecular chain transfer agents (PCysMA or PGSHMA macro-CTAs) are then prepared via RAFT polymerization, which are then chain-extended via aqueous RAFT dispersion polymerization of 2-hydroxypropyl methacrylate. In situ polymerization-induced self-assembly (PISA) occurs to produce sterically-stabilized diblock copolymer nano-objects. Although only spherical nanoparticles could be obtained when PGSHMA was used as the sole macro-CTA, either spheres, worms or vesicles can be prepared using either PCysMA macro-CTA alone or binary mixtures of poly(glycerol monomethacrylate) (PGMA) with either PCysMA or PGSHMA macro-CTAs. The worms formed soft free-standing thermo-responsive gels that undergo degelation on cooling as a result of a worm-to-sphere transition. Aqueous electrophoresis studies indicate that all three copolymer morphologies exhibit cationic character below pH 3.5 and anionic character above pH 3.5. This pH sensitivity corresponds to the known behavior of the poly(amino acid methacrylate) steric stabilizer chains