Acetylenic Tetrathiafulvalene Scaffolds - Intramolecular Charge-Transfer Molecules

On the association of neutral and cationic tris(tetrathiafulvaleno)dodecadehydro[18]annulenes

Here, we report the first X-ray crystal structure of a tetrathiafulvalene-fused dehydroannulene with peripheral ethylthio substituents. In addition, we have subjected this compound to electrochemical and UV-Vis-NIR/ESR spectroelectrochemical studies to elucidate the degree to which the oxidised species associate.

Interactions between tetrathiafulvalene units in dimeric structures - the influence of cyclic cores

A selection of cyclic and acyclic acetylenic scaffolds bearing two tetrathiafulvalene (TTF) units was prepared by different metal-catalyzed coupling reactions. The bridge separating the two TTF units was systematically changed from linearly conjugated ethyne, butadiyne and tetraethynylethene (trans-substituted) units to a cross-conjugated tetraethynylethene unit, placed in either acyclic or cyclic arrangements. The cyclic structures correspond to so-called radiaannulenes having both endo- and exocyclic double bonds. Interactions between two redox-active TTF units in these molecules were investigated by cyclic voltammetry, UV–vis–NIR and EPR absorption spectroscopical methods of the electrochemically generated oxidized species. The electron-accepting properties of the acetylenic cores were also investigated electrochemically.

Synthesis, π-face-selective aggregation, and π-face chiral recognition of configurationally stable C(3)-symmetric propeller-chiral molecules with a π-core

The C3 -symmetric propeller-chiral compounds (P,P,P)-1 and (M,M,M)-1 with planar π-cores perpendicular to the C3 -axis were synthesized in optically pure states. (P,P,P)-1 possesses two distinguishable propeller-chiral π-faces with rims of different heights named the (P/L)-face and (P/H)-face. Each face is configurationally stable because of the rigid structure of the helicenes contained in the π-core. (P,P,P)-1 formed dimeric aggregates in organic solutions as indicated by the results of (1) H NMR, CD, and UV/Vis spectroscopy and vapor pressure osmometry analyses. The (P/L)/(P/L) interactions were observed in the solid state by single-crystal X-ray analysis, and they were also predominant over the (P/H)/(P/H) and (P/L)/(P/H) interactions in solution, as indicated by the results of (1) H and 2D NMR spectroscopy analyses. The dimerization constant was obtained for a racemic mixture, which showed that the heterochiral (P,P,P)-1/(M,M,M)-1 interactions were much weaker than the homochiral (P,P,P)-1/(P,P,P)-1 interactions. The results indicated that the propeller-chiral (P/L)-face interacts with the (P/L)-face more strongly than with the (P/H)-face, (M/L)-face, and (M/H)-face. The study showed the π-face-selective aggregation and π-face chiral recognition of the configurationally stable propeller-chiral molecules.