Triptycene End-Capped Benzothienobenzothiophene and Naphthothienobenzothiophene

Previously it was demonstrated that triptycene end-capping can be used as a crystal engineering strategy to direct the packing of quinoxalinophenanthrophenazines (QPPs) towards cofacially stacked π dimers with large molecular overlap resulting in high charge transfer integrals. Remarkably, this packing motif was formed under different crystallization conditions and with a variety of derivatives bearing additional functional groups or aromatic substituents. Benzothienobenzothiophene (BTBT) and its derivatives are known as some of the best performing compounds for organic field-effect transistors. Here, the triptycene end-capping concept is introduced to this class of compounds and polymorphic crystal structures are investigated to evaluate the potential of triptycene end-caps as synthons for crystal engineering.     

三蝶烯衍生物研究新进展

三蝶烯及其衍生物是一类具有独特三维刚性结构的桥环化合物,由于其诱人的应用前景已经引起了人们极大的关注.简要地综述了三蝶烯衍生物在合成方法学、分子机器、材料化学、主客体化学及有机催化等领域的研究与近5年来的新进展,并对其发展趋势作了展望.     

Synthesis of Polycyclic Aromatic Hydrocarbon‐Based Nanovehicles Equipped with Triptycene Wheels

Two new nanovehicles that have extended aromatic platforms as the cargo zones have been obtained. Two strategies were considered for the formation of the perylene core from two naphthalene precursors. The first was based on a Scholl‐type reaction involving an oxidant, and the second used a brominated derivative to perform a homocoupling reaction. The first strategy failed under diverse coupling conditions in the presence of several strong oxidants. Nevertheless, the use of CoF₃ in trifluoroacetic acid triggered a dimerization reaction between two ester groups of one molecule and the naphthalene unit of another, thereby surprisingly yielding a ten‐membered carbon macrocycle. The second strategy encountered a lack of reactivity of the substrate under several homocoupling conditions. The dimerization was not easily performed but Ullmann‐type conditions ultimately gave the expected product. The low yield and low solubility of the product encouraged us to modify our initial design. The synthesis of a new chassis that incorporated additional tert‐butyl groups improved the solubility of the molecules and also prevented overcyclization of the aromatic platform by blocking these positions. Some p‐phenylene spacers were also intercalated between the iodine and perylene centers to increase the reactivity of the halide towards coupling reactions. Two new chassis were obtained by Scholl‐type oxidative coupling using FeCl₃ as the oxidant. The introduction of four triptycene wheels allowed the formation of the two corresponding nanovehicles.     

Synthesis of Benz[1,2-a]aceanthrylene from Triptycene via Flash Vacuum Thermolysis

Benz[1,2-a]aceanthrylene is prepared from triptycene in 60 % yield by flash vacuum thermolysis at 875° C.     

Triptycene quinones in synthesis: preparation of triptycene cyclopentenedione and its reactivity as a dienophile

Triptycenene quinone 1 was converted to triptycene cyclopentenedione 5 through hydroxyquinone-phenyliodonium ylide formation and thermal ring contraction of the latter. Cyclopentenedione 5 reacts as a dienophile and as a dipolarophile with dienes and nitrile oxides, affording polycyclic adducts bearing the triptycene moiety.     

Marriage of Heterobuckybowls with Triptycene: Molecular Waterwheels for Separating C60 and C70

Exploration of π-conjugated polycycles, particularly those have π-frameworks spread over the three-dimensional space, is essential in materials science and synthetic chemistry as these chemical entities possess featured optoelectronic properties and supramolecular assembly. Herein, the bowl-shaped trichalcogenasumanenes are fused onto three branches of triptycene through pyrazine units, affording waterwheel-like three-dimensional polycycles 4 a/4 b . Because the three branches on 4 a/4 b are chemically equal, the molecular orbitals of 4 a/4 b show degenerate feature that results in the strong UV-Vis absorbance at steady state. 4 a/4 b exhibit photo-induced charge-separation and subsequent charge-redistribution at transient state, leading to excited state absorption in NIR-II window (1165–1400 nm). 4 a/4 b are excellent fullerene receptors, and they form 1 : 1 host-guest complexes with C₆₀/C₇₀ as proved by spectroscopic titrations and single crystal structure analysis. Moreover, 4 a/4 b show much stronger affinity toward C₇₀ than C₆₀. Consequently, 4 a/4 b are able to separate C₆₀ and C₇₀ from their mixture, giving the purity of C₆₀ up to 99.5 %.     

Blurring the Lines between Host and Guest: A Chimeric Receptor Derived from Cucurbituril and Triptycene

We report the synthesis and X‐ray crystal structure of a cucurbituril–triptycene chimeric receptor ( 1 ). Host 1 binds to guests typical of CB[6]–CB[8], but also binds to larger guests such as blue box ( 20 ) and the Fujita square ( 22 ). Intriguingly, the geometries of the 1 ? 20 and 1 ? 22 complexes blur the lines between host and guest in that both components fulfill both roles within each complex. The fluorescence output of 1 is fully quenched by the formation of complexes with pyridinium‐derived guests.     

Triptycene as a rigid, 120° orienting, three-pronged, covalent scaffold for porphyrin arrays

The synthesis of novel porphyrin trimers covalently linked by one central, rigid triptycene unit is described. Reaction of 2,6,14-triiodotriptycene, generated in a three-step synthesis from triptycene, with borylated porphyrins under Suzuki cross-coupling conditions afforded porphyrin trimers. In addition, Sonogashira cross-coupling conditions could be successfully applied for the synthesis of trimeric porphyrin arrays as well.     

Triptycene End-Capped Quinoxalinophenanthrophenazines (QPPs): Influence of Substituents and Conditions on Aggregation in the Solid State

Triptycene end-capped quinoxalinophenanthrophenazine reveals a coplanar arrangement with a high overlap of the π planes. Four structurally related model compounds bearing electron-withdrawing or -donating groups were synthesized, and their optoelectronic properties were characterized by using cyclovoltammetry, absorption- and emission spectroscopy as well as theoretical calculations. The directional robustness of the triptycene end-capping of these compounds was tested by using single-crystal X-ray diffraction. The impact of solvents and crystallization conditions has also been investigated. In total, 17 single-crystal structures were obtained. Each structure was evaluated for its potential charge-transfer capability taking into account the overall molecular packing, solvent enclathration and the structural overlap of the π planes of adjacent molecules. For this purpose, charge-transfer integrals were also calculated for every π-stacked dimer.     

Microporous Polymers from a Carbazole‐Based Triptycene Monomer: Synthesis and Their Applications for Gas Uptake

Two kinds of novel organic microporous polymers TCP s ( TCP‐A and TCP‐B ) were prepared by two cost‐effective synthetic strategies from the monomer of tricarbazolyltriptycene ( TCT ). Their structure and properties were characterized by FT‐IR, solid ¹³C NMR, powder XRD, SEM, TEM, and gas absorption measurements. TCP‐B displayed a high surface area (1469 m² g^?1) and excellent H₂ storage (1.70 wt % at 1 bar/77 K) and CO₂ uptake abilities (16.1 wt % at 1 bar/273 K), which makes it a promising material for potential application in gas storage.     

Electroactive polymers including non-linear optical polymers

Recent advances in design, synthesis, and processing of electroactive polymers promise important commercial applications ranging from improved performance flat panel displays to critical components of the next generation information superhighway. Electroactive polymer research is also providing fundamental new insight into the role of long range electrostatic interactions with consequences for condensed matter theory and the development of nanostructured materials.     

Reaction of chlorine-containing polymers with living polymers

A graft polymer was prepared by means of the coupling reaction of chlorinated ethylene–propylene terpolymer with living polystyrene, obtained with a sodium–naphthalene complex as initiator, under various conditions; the grafting efficiency and the percentage of grafting are discussed. Poly(chloroprene), chlorinated butyl rubber, poly(vinyl chloride), poly(epichlorohydrin), and epichlorohydrin–ethylene oxide copolymer were also used as chlorine-containing polymers. The grafting efficiencies were found to be in the following order: chlorinated butyl rubber > poly(epichlorohydrin) > epichlorohydrin-ethylene oxide copolymer > chlorinated ethylene-propylene terpolymer > poly(chloroprene) > poly(vinyl chloride). A graft polymer was obtained from the reaction between chlorinated ethylene–propylene terpolymer and living poly(isoprene), with butyllithium in benzene. The undesirable metal–halogen interchange reaction was considerable.     

Low surface energy polymers and surface-active block polymers. III. Adamantyl-containing polymers

Two adamantyl-containing oxazoline monomers. 2-(1-adamantyl)-2-oxazoline, A , and 2-(1-adamantylmethyl)-2-oxazoline, B , were synthesized, and polymerized in 1,2-dichlorobenzene to give polymers PA and PB respectively. Both polymers are highly crystalline and showed very high T_m's (269°C for PA and 320°C for PB ) and little solubility in common organic solvents. Annealed PA showed a critical surface tension of 23.6 dyne/cm. PB was not soluble in the many organic solvents tested at room temperature. Due to its high T_m and insolubility, contact angle measurements on PB were impossible. Diblock copolymers based on different weight ratios of A and 2-ethyl-2-oxazoline, E , showed relatively narrow molecular weight distribution (MWD) when methyl p-nitrobenzenesulfonate, I , was used as initiator. After annealing, diblock polymers with B/I = 7, 10, or 12 showed T_m's (200–281°C); after quenching the same samples showed T_c's (160–171°C), which were lower than that of pure PB , 215°C. The quenched diblocks showed single T_g's (63–82°C) which implies that these short blocks are compatible. Diblock polymer with B/I = 5 and E/I = 20 was amorphous and displayed inverse emulsifying ability in styrene + water emulsion polymerization. BEB type triblock polymers prepared using ethylene glycol dinosylate as initiator had broader MWD and higher T_m's compared to their diblock counterparts with the same B/E wt% and B/I ratios. These triblock polymers were not completely soluble in styrene and/or water and therefore could not be used as emulsifying agents.     

Organosilane polymers: Formable polymers containing methylsilylene units

Organosilane polymers containing methylsilylene units were prepared by sodium condensation of MeHSiCl₂ alone or with R¹R²SiCl₂ (R¹ and R² = alkyl, aryl, or aralkyl) in a blend of toluene and dioxane followed by fast filtration under N₂. These polymers are readily soluble in common solvents and can be drawn into fibers or formed into films by molding, casting, or potting. They can be crosslinked by oxidation, irradiation, or hydrosilylation of vinylsilane in the presence of platinum complexes. The effect of the quantity of MeHSiCl₂ on molecular weights of copolymers was also discussed.     

Heteroorganic polymers

Summary Polymers were obtained from the bis-ethynyl compounds of silicon and germanium, containing unsaturated carbon-carbon groupings in the chain, alternating with silicon and germanium atoms.     

Benzobistriazolophenanthroline polymers

The polycondensation of aromatic dihydrazidines (bisamidrazones) with 1,4,5,8-naphthalenetetracarboxylic acid or 1,4,5,8-naphthalenetetracarboxylic dianhydride in polyphosphoric acid led to high yields of soluble benzobistriazolophenanthroline polymers. Inherent viscosities in methanesulfonic acid of 0.25–2.51 dl g were recorded. Prior to polymer synthesis, a series of model compounds were prepared by reactions analogous to the polycondensation reaction. The polymer structure was established by elemental analysis and spectral comparisons of the polymers with model compounds. The thermal properties of the polymers were studied by thermal gravimetric analysis, differential thermal analysis, differential scanning calorimetry, and softening under load. Onset of breakdown in an air atmosphere occurs in the 440–450°C range. No softening under load was observed up to 450°C.     

Resacetophenone-furfural polymers

Poly(resacetophenone-furfural) was prepared by condensing resacetophenone with furfural in the presence of the optimum concentrations of various acidic catalysts. The polymer samples were characterized by elemental analyses, i.r. spectra and TGA. The number-average molecular weights were determined both by vapour pressure osmometry and non-aqueous titration. Intrinsic viscosities of the polymers were measured in DMF. Polymeric metal chelates of Cu²⁺, Fe³⁺, Co²⁺, Zn²⁺, Mn²⁺, Ni²⁺ were prepared and characterized.     

Epoxy polymers

The current use of non-isothermal DTA or DSC for the investigation of polymers is based upon assumptions which allow a number of conclusions supported only by data drawn from the DTA or DSC traces of prepolymer samples. A more adequate procedure involving the analysis of the DTA or DSC traces of several samples previously cured to different polymerization degrees under isothermal conditions is proposed. A comparison of the results obtained with the two procedures is reported for two composite materials.