Triphenylantimony(V) Catecholates of the Type (3-RS-4,6-DBCat)SbPh3-Catechol Thioether Derivatives: Structure, Electrochemical Properties, and Antiradical Activity

Abstract

A new series of triphenylantimony(V) 3-alkylthio/arylthio-substituted 4,6-di-tert-butylcatecholates of the type (3-RS-4,6-DBCat)SbPh3, where R = n-butyl (1), n-hexyl (2), n-octyl (3), cyclopentyl (4), cyclohexyl (5), benzyl (6), phenyl (7), and naphthyl-2 (8), were synthesized from the corresponding catechol thioethers and Ph3SbBr2 in the presence of a base. The crystal structures of 1, 2, 3, and 5 were determined by single-crystal X-ray analysis. The coordination polyhedron of 1–3 is better described as a tetragonal pyramid with a different degree of distortion, while that for 5- was a distorted trigonal bipyramid (τ = 0.014, 0.177, 0.26, 0.56, respectively). Complexes demonstrated different crystal packing of molecules. The electrochemical oxidation of the complexes involved the catecholate group as well as the thioether linker. The introduction of a thioether fragment into the aromatic ring of catechol ligand led to a shift in the potential of the “catechol/o-semiquinone” redox transition to the anodic region, which indicated the electron-withdrawing nature of the RS group. The radical scavenging activity of the complexes was determined in the reaction with DPPH radical.

Green electro-organic synthesis of a novel catechol derivative based on o-benzoquinone nucleophilic addition

“…7,16–21 It is used as a raw material in many industries such as photography, dye, cosmetics, chemical, and pharmaceutical industries. 7,8,10,13,17,19,22,23 In addition, catechol has biological importance and acts as an antioxidant and antiradical 24,25 due to its high electron transfer. Many drugs used in cancer therapy, such as adriamycin, carbazilquinone, doxorubicin, daunorubicin, and mitomycin C contain catechol, 7,18,20,26,27 while various other quinones have different applications in the industry.…”

Synthesis and Antioxidant Activity of New Catechol Thioethers with the Methylene Linker

“…Along with the pronounced biological activity, these compounds are widely used to obtain functionalized materials [ 13 , 14 , 15 , 16 ]; they serve as building blocks for coatings design [ 17 ], as the basis for organic batteries and redox capacitors [ 18 , 19 ], and as redox-based molecular memory-films [ 20 ] due to their ability to accept, store and donate electrons and protons. Researchers consider S-functionalized sterically hindered catechols (quinones) as promising chelating ligands in metal complexes [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ], polynuclear compounds and coordination polymers [ 28 , 29 ].…”

Binuclear Triphenylantimony(V) Catecholates through N-Donor Linkers: Structural Features and Redox Properties

“…Triarylantimony(V) o-amidophenolates [ 47 , 48 ], as well as some triarylantimony(V) catecholates with electron-donor substituents [ 49 , 50 , 51 ], represent the first class of main group metal complexes, which can bind the molecular oxygen in a reversible manner. The related antimony(V) catecholates were found to be active in a radical scavenging [ 52 , 53 , 54 ], can be considered prospective inhibitors of oxidation processes, such as lipid peroxidation [ 55 , 56 ]. The modification of molecular structure and redox-properties of triorganylantimony(V) catecholates is possible via the use of different donor/acceptor substituents in a redox-active ligand [ 50 , 57 ], at organic groups bound to antimony [ 58 , 59 , 60 ], or coordination of a neutral or ionic ligand to the central antimony atom [ 61 , 62 , 63 ].…”