Multi-functional imidazolium dendrimers based on thiacalix[4]arenes: self-assembly, catalysis and DNA binding.

For the first time, dendrimers based on thiacalix[4]arenes bearing imidazolium dendrons on one side and alkyl fragments on another side of the macrocyclic platform and symmetrical dendrimers with four dendrons on both sides were synthesized. Dendrons consist of gallic acid-based branches functionalized with imidazolium and triazolium groups. The physicochemical properties of the dendrimers such as micellar concentration (CMC), size, and solubilization capacity were measured. Novel dendrimers exhibit high binding efficiency with calf thymus DNA (ctDNA) as revealed by fluorescence quenching of the DNA-EtBr complex in the presence of macrocycles. Dendrimers have been used as supports for Pd nanoparticles, which show high catalytic activity for the reduction of nitroaromatic compounds.

New Calix[4]arene-Fluoresceine Conjugate by Click Approach-Synthesis and Preparation of Photocatalytically Active Solid Lipid Nanoparticles.

New fluorescent systems for photocatalysis, sensors, labeling, etc., are in great demand. Amphiphilic ones are of special interest since they can form functional colloidal systems that can be used in aqueous solutions. A new macrocycle platform for click chemistry and its adduct with o-propargylfluoresceine was synthesized and characterized using modern physical techniques. Nanosized solid lipid nanoparticles (SLNs) from the calixarene-fluoresceine adduct were synthesized through the solvent injection technique and well-characterized in the solution and in solid state using light-scattering and microscopy methods. The maximum fluorescence intensity of the SLNs was found to be in the pH range from 7 to 10. The Förster resonance energy transfer (FRET) efficiency from SLNs to rhodamine 6g was found to be 97.8%. Finally, pure SLNs and the FRET system SLNs-Rh6G were tested in model photocatalytic ipso oxidative hydroxylation of phenylboronic acid under blue LED light. The SLNs-Rh6G system was found to be the best, giving an almost qualitative phenol yield, which was shown by HPLC-UV analysis.