A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin
We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Q…
Iridium(III) Complexes with Phenyl-tetrazoles as Cyclometalating Ligands
Ir(II) cationic complexes with cyclometalating tetrazolate ligands were prepared for the first time, following a two-step strategy based on (i) a silver-assisted cyclometalation reaction of a tetrazole derivative with IrCl3 affording a bis-cyclometalated solvato-complex P ([Ir(ptrz)(2)(CH3CN)(2)](+), Hptrz = 2-methyl-5-phenyl-2H-tetrazole); (ii) a substitution reaction with five neutral ancillary ligands to get [Ir(ptrz)(2)L](+), with L = 2,2'-bypiridine (1), 4,4'-di-tert-butyl-2,2'-bipyridine (2), 1,10-phenanthroline (3), and 2-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridine (4), and [Ir(ptrz)(2)L-2](+), with L = tertbutyl isocyanide (5). X-ray crystal structures of P, 2, and 3 were solved. Elect…
Nanosponges for the protection and release of the natural phenolic antioxidants quercetin, curcumin and phenethyl caffeate
The inclusion of polyphenols into nanoporous materials may significantly improve their application as radical trapping agents for therapeutic purposes. In the present work, nanosponges based on hypercross- linked cyclodextrins and calixarenes (NS1–NS3) were used as carriers of three natural phenolic antioxidants: quercetin (Que), curcumin (Cur) and phenethyl caffeate (Phec). Good w/w loadings, namely 7.3% for the Que–NS1 composite, 17.3% for Cur–NS2 and 12.9% for Phec–NS3, were achieved. The release kinetics and the inhibition rate constants (kinh) of the reaction with alkylperoxyl radicals (ROO.) in 0.1 M phosphate buffer solutions at pH 7.4 were studied and indicated better antioxidant ac…
Anionic Cyclometalated Iridium(III) Complexes with a Bis-Tetrazolate Ancillary Ligand for Light-Emitting Electrochemical Cells
none 10 si A series of monoanionic Ir(III) complexes (2-4) of general formula [Ir(C^N)2(b-trz)](TBA) are presented, where C^N indicates three different cyclometallating ligands (Hppy = 2-phenylpyridine; Hdfppy = 2-(2,4-difluoro-phenyl)pyridine; Hpqu = 2-methyl-3-phenylquinoxaline), b-trz is a bis-tetrazolate anionic N^N chelator (H2b-trz = di(1H-tetrazol-5-yl)methane), and TBA = tetrabutylammonium. 2-4 are prepared in good yields by means of the reaction of the suitable b-trz bidentate ligand with the desired iridium(III) precursor. The chelating nature of the ancillary ligand, thanks to an optimized structure and geometry, improves the stability of the complexes, which have been fully char…
CCDC 987700: Experimental Crystal Structure Determination
Related Article: Filippo Monti, Andrea Baschieri, Isacco Gualandi, Juan J. Serrano-Pérez, José M. Junquera-Hernández, Domenica Tonelli, Andrea Mazzanti, Sara Muzzioli, Stefano Stagni, Cristina Roldan-Carmona, Antonio Pertegás, Henk J. Bolink, Enrique Ortí, Letizia Sambri, and Nicola Armaroli|2014|Inorg.Chem.|53|7709|doi:10.1021/ic500999k
CCDC 1555727: Experimental Crystal Structure Determination
Related Article: Elia Matteucci, Andrea Baschieri, Andrea Mazzanti, Letizia Sambri, Jorge Ávila, Antonio Pertegás, Henk J. Bolink, Filippo Monti, Enrico Leoni, and Nicola Armaroli|2017|Inorg.Chem.|56|10584|doi:10.1021/acs.inorgchem.7b01544
CCDC 987698: Experimental Crystal Structure Determination
Related Article: Filippo Monti, Andrea Baschieri, Isacco Gualandi, Juan J. Serrano-Pérez, José M. Junquera-Hernández, Domenica Tonelli, Andrea Mazzanti, Sara Muzzioli, Stefano Stagni, Cristina Roldan-Carmona, Antonio Pertegás, Henk J. Bolink, Enrique Ortí, Letizia Sambri, and Nicola Armaroli|2014|Inorg.Chem.|53|7709|doi:10.1021/ic500999k
CCDC 987699: Experimental Crystal Structure Determination
Related Article: Filippo Monti, Andrea Baschieri, Isacco Gualandi, Juan J. Serrano-Pérez, José M. Junquera-Hernández, Domenica Tonelli, Andrea Mazzanti, Sara Muzzioli, Stefano Stagni, Cristina Roldan-Carmona, Antonio Pertegás, Henk J. Bolink, Enrique Ortí, Letizia Sambri, and Nicola Armaroli|2014|Inorg.Chem.|53|7709|doi:10.1021/ic500999k