Self-assembly of a metal-organic cage-like structure bearing cofacial redox-active bis-(-semiquinone) copper(II) units.

Ditopic di--quinone with a resorcinol bridge exhibits the ability to self-assemble in a reaction with copper, giving a cage-like binuclear complex that, due to the cofacially placed metal ions, is capable of encapsulation of different solvent molecules as guest ligands. Notably, the geometry of the internal cavity of this complex adjusts depending on the coordinating properties of the encapsulated molecule (mono- or bidentate). A feature of this species is that the cage-forming units are copper(II) bis-semiquinonate moieties, capable of undergoing ligand-centered redox transformations.

Annulation of a 1,3-dithiole ring to a sterically hindered -quinone core. Novel ditopic redox-active ligands.

The fused 1,3-dithiole spacer seems to be very suitable for the functionalization of sterically hindered -quinones with additional groups capable of coordination of metal ions and/or possessing a redox activity. An effective method for the synthesis of sterically hindered -quinones containing 1,3-diketonate, dinitrile and -quinone-methide functional groups at the periphery of the ligand has been developed. The novel compounds have rigid and conjugated structures and exhibit properties typical of -quinones.

Redox-Modulations of Photophysical and Single-molecule Magnet Properties in Ytterbium Complexes Involving Extended-TTF Triads.

The reaction between the 2,2'-benzene-1,4-diylbis(6-hydroxy-4,7-di--butyl-1,3-benzodithiol-2-ylium-5-olate triad () and the metallo-precursor [Yb(hfac)]2HO led to the formation of a dinuclear coordination complex of formula [Yb(hfac)()]0.5CHCl (). After chemical oxidation of in 2,2'-cyclohexa-2,5-diene-1,4-diylidenebis(4,7-di--butyl-1,3-benzodithiole-5,6-dione (), the latter triad reacted with the [Yb(hfac)]2HO precursor to give the dinuclear complex of formula [Yb(hfac)()] ().

Regioisomerism in coordination chemistry: oxidative addition of a bifunctional ligand to palladium, stabilized with 1,2-bis(diphenylphosphino)ethane.

A unique phenomenon of regioisomerism in coordination chemistry was discovered: the reaction of a sterically hindered o-quinone annelated with a dithiete ring with Pddba in the presence of 1,2-bis(diphenylphosphino)ethane (dppe) gave a mixture of two regioisomers: catecholate 3Cat and dithiolate 3Dit. Both isomers were isolated in crystalline form and characterized by NMR, IR and X-ray diffractometry studies. DFT calculations reveal that the 3Dit species is more thermodynamically stable than the isomer 3Cat.

Protonated paramagnetic redox forms of di--quinone bridged with -phenylene-extended TTF: A EPR spectroscopy study.

The chemical oxidation and reduction processes of deprotonated, direduced -quinone-exTTF--quinone in protic solvents were studied by EPR spectroscopy. The formation of relatively stable paramagnetic protonated redox forms of the parent triad was very surprising. The character of spin-density distribution in the semiquinone-quinone and semiquinone-catechol redox forms indicates that the -phenylene-extended tetrathiafulvalene connector provides a quite effective electronic communication channel between dioxolene coordination sites.