Luminescence and morphological behaviour of the aromatic dipeptide pair having singular structural variability.

In the present manuscript, the luminescence and the self-assembly behaviour of two aromatic dipeptides with a singular structure variable are investigated. The terminally protected dipeptides tryptophan-tyrosine (WYp ) and tryptophan-phenylalanine (WFp ) were synthesized using a standard solution phase procedure. Significant solvatochromic effect was observed for both the dipeptidyl entities; whilst the influence was more pronounced for the WYp entity when compared with WFp . Interesting morphological variation was observed for WFp and WYp , in which discrete and interconnected nanospheres were observed for the respective dipeptides. The results obtained signify the influence of the singular structural variation on modulating the overall functional behaviour of the short peptides motifs.

Investigating the spectral and electrochemical properties of novel flavin-pyrene dyads separated via variable spacer.

The present manuscript describes the synthesis and the photophysical properties of a pair of novel flavin-pyrene dyads where the donor and the acceptor entities are separated via variable spacer. The dyads were well characterized using standard techniques and investigated for their photophysical and electrochemical nature. The observed absorption spectra of the dyads mainly display peaks corresponding to the individual pyrene and flavin units, with some contribution from the flavin entity in the pyrene region. While, strong emission quenching was observed for both the dyads if compared to its individual constituents. However, a careful analysis of the emission spectra and the solvent dependent studies reveals subtle difference between the two dyads. While no significant difference could be observed when excited in the flavin region; excitation at the pyrene region displays a weak and broad emission band in case of closely connected dyad. Further, the electrochemical properties were investigated by cyclic voltammetry and the reduction ability was observed to follow the trend as FlPy2 < FlPy1 < Fl.

Recent advances in AIEgen-based chemosensors for small molecule detection, with a focus on ion sensing.

Since the aggregation-based emission (AIE) phenomenon emerged in 2001, numerous chemical designs have been built around the AIE concept, displaying its utility for diverse applications, including optics, electronics, energy, and biosciences. The present review critically evaluates the broad applicability of AIEgen-based chemical models towards sensing small analytes and the structural design strategies adjusting the mode of action reported since the last decade. Various AIEgen models have been discussed, providing qualitative and quantitative estimation of cationic metal ions and anionic species, as well as biomolecular, cellular, and organelle-specific probes. A systematic overview of the reported structural design and the underlying working mode will pave the way for designing and developing the next generation of AIEgens for specific applications.

Modulating catalytic activity of a modified flavin analogue via judicially positioned metal ion toward aerobic sulphoxidation.

This manuscript describes the synthesis, spectroscopic and crystallographic characterization of a cadmium complex of 10-propoylisoalloxazine-7-carboxylic acid (Flc-Cd). Catalytic activity of Flc-Cd towards aerobic sulphoxidation reaction was investigated in the presence of l-ascorbic acid as the reducing agent. Notably the neutral un-metalated flavin analogue did not show any significant catalytic activity. The design strategy for Flc provides a close proximity of the metal centre to the flavin core without compromising the catalytic site thereby assisting the product formation when compared to unmetallated Flc. Minor enantioselectivity is also observed in cases where unsymmetrical sulphides were used; indicative of the possible involvement of chiral l-ascorbic acid in the intermediate formation.