Tetrathiafulvalene based phosphino-oxazolines: a new family of redox active chiral ligands

Chiral Bis(tetrathiafulvalene)-1,2-cyclohexane-diamides

Chiral bis(TTF) diamides have been obtained in good yields (54-74%) from 1,2-cyclohexane-diamine and the corresponding TTF acyl chlorides. The (R,R)-1 and (S,S)-1 enantiomers have been characterized by circular dichroism and the racemic form by single-crystal X-ray diffraction. The neutral racemic bis(TTF)-diamide shows the formation of a pincer-like framework in the solid state, thanks to the intramolecular S···S interactions. The chemical oxidation in a solution using FeCl₃ provides stable oxidized species, while the electrocrystallization experiments provided radical cation salts. In particular, single-crystal resistivity measurements on the racemic donor with AsF₆^- as a counterion demonstrate semiconductor behavior in this material. The DFT and TD-DFT calculations support the structural and chiroptical features of these new chiral TTF donors.

Modern History of Organic Conductors: An Overview

This short review article provides the reader with a summary of the history of organic conductors. To retain a neutral and objective point of view regarding the history, background, novelty, and details of each research subject within this field, a thousand references have been cited with full titles and arranged in chronological order. Among the research conducted over ~70 years, topics from the last two decades are discussed in more detail than the rest. Unlike other papers in this issue, this review will help readers to understand the origin of each topic within the field of organic conductors and how they have evolved. Due to the advancements achieved over these 70 years, the field is nearing new horizons. As history is often a reflection of the future, this review is expected to show the future directions of this research field.

Nature of the E⋯E′ interactions (E, E′ = O, S, Se, and Te) at naphthalene 1,8-positions with fine details of the structures: experimental and theoretical investigations

The nature of E⋯E′ in 1-RE–8-R′E′C₁₀H₆ (E/E′ = O, S, Se and Te) is clarified with the QTAIM approach and NBO analysis, after structural determinations.

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

Enantiopure (R,R) and (S,S)-dimethyl-bis(ethylenedithio)tetrathiafulvalene monosulfones have been synthesized by the aerial oxidation of the chiral dithiolates generated from the propionitrile-protected precursors. Both enantiomers crystallize in the orthorhombic chiral space group P2₁2₁2₁. They show a boat-type conformation of the TTF moiety, a rather rigid dithiin sulfone ring and the methyl groups in a bisequatorial conformation. Cyclic voltammetry measurements indicate fully reversible oxidation in radical cation and dication species.

Stereoisomeric semiconducting radical cation salts of chiral bis(2-hydroxypropylthio)ethylenedithioTTF with tetrafluoroborate anions

A new chiral TTF-based donor has produced enantiopure R,R and S,S radical cation salts with the tetrafluoroborate anion as well as the nearly isostructural meso/racemate mixture.

Polar coordinate representation of Hb(rc) versus (h2/8m)nabla2rhob(rc) at BCP in AIM analysis: classification and evaluation of weak to strong interactions

Polar coordinate (R, theta) representation is proposed for the plot of Hb(rc) versus (h2/8m)nabla2rhob(rc) in AIM analysis to classify, evaluate, and understand weak to strong interactions in a unified way and in more detail; Hb(rc) and nabla2rhob(rc) are total electron energy densities and the Laplacian of rhob(rc) at bond critical points (BCPs: rc), respectively, where rhob(rc) are electron densities at rc. Both the x- and y-axes of the plot are expressed in the common unit of energy since Hb(rc) = Gb(rc) + Vb(rc) and (h2/8m)nabla2rhob(rc) = Hb(rc) - Vb(rc)/2 (= Gb(rc) + Vb(rc)/2), where Gb(rc) and Vb(rc) are kinetic energy densities and potential energy densities, respectively. Data employed for the plot are calculated at BCPs for full-optimized structures and optimized structures with the fixed distances (r) of r = r(o) + wa(o), where r(o) are the full-optimized distances, a(o) is the Bohr radius, and w = +/-0.1 and +/-0.2. The plot draws a helical stream starting from near origin (Hb(rc) = (h2/8m)nabla2rhob(rc) = 0) for very weak interactions and turns to the right as interactions become stronger. The helical stream is well described by the polar coordinate representation with (R, theta); R is given in the energy unit, and theta in degrees is measured from the y-axis. The ratio of Vb(rc)/Gb(rc) (= k) controls theta, of which an acceptable range in the plot is 45.0 < theta < 206.6 degrees. Each plot for an interaction gives a curve, which supplies important information. It is expressed by theta(p) and kappa(p); theta(p) corresponds to the tangent line measured from the y-direction, and kappa(p) is the curvature of the plot at w = 0. The polar coordinate (R, theta) representation with (theta(p), kappa(p)) helps us to classify, evaluate, and understand the nature of weak to strong interactions in a unified way.

Fine structures of 8-G-1-(p-YC6H4C identical with CSe)C10H6 (G = H, Cl, and Br) in crystals and solutions: ethynyl influence and Y- and G-dependences

Fine structures of 8-G-1-(p-YC₆H₄C ≡ CSe)C₁₀H₆ [1 (G = H) and 2 (G = Cl): Y = H (a), OMe (b), Me (c), F (d), Cl (e), CN (f), and NO₂ (g)] are determined by the X-ray analysis. Structures of 1, 2, and 3 (G = Br) are called A if each Se–C_sp bond is perpendicular to the naphthyl plane, whereas they are B when the bond is placed on the plane. Structures are observed as A for 1a–c bearing Y of nonacceptors, whereas they are B for 1e–g with Y of strong acceptors. The change in the structures of 1e–g versus those of 1a–c is called Y-dependence in 1. The Y-dependence is very specific in 1 relative to 1-(p-YC₆H₄Se)C₁₀H₇ (4) due to the ethynyl group: the Y-dependence in 1 is almost inverse to the case of 4 due to the ethynyl group. We call the specific effect “Ethynyl Influence.” Structures of 2 are observed as B: the A-type structure of 1b changes dramatically to B of 2b by G = Cl at the 8-position, which is called G-dependence. The structures of 2 and 3 are examined in solutions based on the NMR parameters.