No abstract

Urea modified tryptophan has been used as an in situ reducing and stabilizing agent for the fabrication of gold nanoparticles and the gold nanoparticles efficiently catalyzed the Suzuki–Miyaura cross-coupling reaction in water.

A series of peptides (1-3) containing m-nitrocinnamic acid, αaminoisobutyric acid (Aib) and L-leucine has been synthesized and their antileishmanial propensities have been studied. The compound 1 was synthesized by condensation reaction of 3nitrobenzaldehyde and malonic acid. The compound 1 forms duplex by intermolecular hydrogen bonding interactions in solid state and finally self-assemble to form supramolecular helix through C-H⋅⋅⋅O hydrogen bonds. The peptide 2 shows antiparallel sheet-like assembly through intermolecular N-H⋅⋅⋅O and C-H⋅⋅⋅O hydrogen bonding interactions. The peptide 3 adopts extended conformation and self-assemble to form bowl-like morphology. Moreover, the peptide 3 exhibits significant growth inhibition property on Leishmania major promastigotes with an IC 50 value of 13 μg/ml. But compound 1 and peptide 2 have IC 50 values 100 μg/ml and 41 μg/ml respectively. The higher lipophilicity of peptide 3 may increase the chances of reaching this intracellular parasite. Thus peptide 3 shows selective toxicity towards Leishmania (IC 50 = 13 μg/ml) and compared to several existing standard antileishmanial drugs like pentastam (IC 50 > 64 μg/ml), sodium stibogluconate (IC 50 > 64 μg/ml) or ketoconazole (IC 50 = 72 μg/ml), peptide 3 shows at least 2-6 times higher potency.[a] M.

The development of engineered hybrid systems by encapsulating nanoparticles in gel scaffolds and their synergistic effects are highly crucial for the fabrication of advanced functional materials. Herein, a series of dipeptides containing an aromatic amino acid at the N-terminal and an aliphatic amino acid at the C-terminal were synthesized and studied. Among them, only the dipeptide L-Phe-L-Val can form both hydro-and organogelator, depending on the N-and C-terminal protecting groups. The organogel shows bright blue emission under 366 nm UV irradiation; however, the hydrogel does not show such blue emission. Such kind of emission may be due to the self-assembly and high degree of aggregation in the gel state of the phenyl ring. The blue-emitting organogel efficiently encapsulates green emission source CdSe quantum dots and red emission source LD 700 perchlorate dye. The resulting organic− inorganic hybrid gel exhibits white light emission due to the synergistic effect under 366 nm UV irradiation.

The crystal plasticity, due to bromine–bromine interactions, plays a crucial role in generating a slip plane and thus, under mechanical force, crystals undergo bending without affecting their fluorescent properties.