https://www.selleckchem.com/products/pentetic-acid.html In the past months, the use of the drug hydroxychloroquine has considerably increased in many countries, associated with a proposed treatment for the COVID-19 disease. Although there is no conclusive evidence about the efficacy of the drug for this purpose, surprisingly there are no conclusive studies in the literature concerning its mechanism of action inside cells, which is related to its interaction with nucleic acids. Here, we performed a robust characterization of the interaction between hydroxychloroquine and double-stranded DNA using single-molecule force spectroscopy and gel electrophoresis. Two different binding modes were identified, namely, minor groove binding for low drug concentrations and intercalation for high drug concentrations, and the sets of binding parameters were determined for each of these modes. Such results have unraveled in detail the molecular mechanism of action of the drug as a DNA ligand.Lead-free double perovskites have attracted noteworthy attention due to their compositional flexibility and electronic diversity. In this study, we hydrothermally grow a new class of Cs2Ag x Na1-xFeCl6 (0 ≤ x ≤ 1) perovskite single crystals with high thermal stability. The substitution of B-site cation allows to regulate the crystallographic and band structure, which gives rise to enlarged band absorbance close to the near-infrared region (∼800 nm) via composition engineering. Ultrafast transient absorption spectroscopy (TAS) certifies that the decay time of excited-state absorption is 5.02 and 2450 ps in the case of Cs2NaFeCl6 and Cs2AgFeCl6, respectively. The corresponding charge carrier diffusion length accordingly enhances from 3.7 to 311 nm by means of increasing Ag dopant concentration. Structurally, the primitive cell shrinks due to the partial replacement of [NaCl6]5- octahedra by [AgCl6]5- octahedra. It is proved theoretically as well as experimentally that the introduction of Ag species