Sathish Kumar Mudedla

Au22Ir3(PET)18: An Unusual Alloy Cluster through Intercluster Reaction

An intercluster reaction between Au25(PET)18 and Ir9(PET)6 producing the alloy cluster, Au22Ir3(PET)18 exclusively, is demonstrated where the ligand PET is 2-phenylethanethiol. Typical reactions of this kind between Au25(PET)18 and Ag25(SR)18, and other clusters reported previously, produce mixed cluster products. The cluster composition was confirmed by detailed high-resolution electrospray ionization mass spectrometry (ESI MS) and other spectroscopic techniques. This is the first example of Ir metal incorporation in a monolayer-protected noble metal cluster. The formation of a single product was confirmed by thin layer chromatography (TLC). Density functional theory (DFT) calculations suggest that the most favorable geometry of the Au22Ir3(PET)18 cluster is one wherein the three Ir atoms are arranged triangularly with one Ir atom at the icosahedral core and the other two on the icosahedral shell. Significant contraction of the metal core was observed due to strong Ir-Ir interactions.

Design, synthesis and metal sensing studies of ether-linked bis-triazole derivatives

Ether-linked-bis-triazole derivatives have been synthesized by (CuAAC) “Click” reaction and well characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. Application of these materials in the field of sensors has also been demonstrated using various spectroscopic techniques. The interaction of the compound with Hg2+ was further confirmed by computational studies.

Design and synthesis of sugar-triazole based uracil appended sugar-imine derivatives – an application in DNA binding studies

Several sugar-triazole derivatives were synthesized and characterized by spectroscopic techniques. The interaction of the sugar-triazoles with CT-DNA was explored, which revealed that all the compounds could interact with CT-DNA through groove binding, which was further supported by a docking analysis.

Bent Keto Form of Curcumin, Preferential Stabilization of Enol by Piperine, and Isomers of Curcumin∩Cyclodextrin Complexes: Insights from Ion Mobility Mass Spectrometry

A detailed examination of collision cross sections (CCSs) coupled with computational methods has revealed new insights into some of the key questions centered around curcumin, one of the most intensively studied natural therapeutic agents. In this study, we have distinguished the structures and conformers of the well-known enol and the far more elusive keto form of curcumin by using ion mobility mass spectrometry (IM MS). The values of the theoretically predicted isomers were compared with the experimental CCS values to confirm their structures. We have identified a bent structure for the keto form and the degree of bending was estimated. Using IM MS, we have also shown that ESI MS reflects the solution phase structures and their relative populations, in this case. Piperine, a naturally occurring heterocyclic compound, is known to increase the bioavailability of curcumin. However, it is still not clearly understood which tautomeric form of curcumin is better stabilized by it. We have identified preferential stabilization of the enol form in the presence of piperine using IM MS. Cyclodextrins (CDs) are used as well-known carriers in the pharmaceutical industry for increasing the stability, solubility, bioavailability, and tolerability of curcumin. However, the crystal structures of supramolecular complexes of curcumin∩CD are unknown. We have determined the structures of different isomers of curcumin∩CD (α- and β-CD) complexes by comparing the CCSs of theoretically predicted structures with the experimentally obtained CCSs, which will further help in understanding the specific role of the structures involved in different biological activities.