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(Z)-7-Aryl-5-acyldibenzo[e,g][1,4]diazocin-6(5H)-one, a unique saddle-shaped bridged biaryl containing synchronized aryl-aryl and N-aryl stereogenic axes, was constructed for the first time in good...

The application of exotic conjugated skeletons in organic semiconductors is alluring due to the topology related optoelectronic peculiarities. In this paper we explore the design of molecular semiconductors starting from the saddle-shaped o-tetraphenylene (OTP) for the first time. The in silico tailored molecular semiconductor OTPE-OMeTPA with extended π-conjugation presents an improved hole mobility in comparison with its counterpart OTP-OMeDPA, due to the reduced reorganization energy and the larger intermolecular centroid distance. Molecular dynamics simulations clarify the atomic-scale microscopic origins of glass transition in the pristine materials and their p-doping promotor containing composites, being associated with the torsional motion of central OTP and the translational motion of all centroids, respectively. The OTPE-OMeTPA based organic composite displays desirable combined properties of conductivity, glass transition temperature, solution processibility, and interfacial charge transfer kinetics, allowing for the fabrication of thermostable perovskite solar cells with 21.5% power conversion efficiency. A comprehensive comparison of device degradation is also performed by joint experimental measurements and theoretical modeling, laying a solid foundation for further materials and device development.

The reaction of 2,2'-dibromo-biphenyl on a Ag(111) surface leads to the formation of planar acenes with a high-regioselectivity rather than nonplanar saddle-shaped tetraphenylene as the typical product in solution chemistry. The regioselective aryl-aryl coupling reaction is attributed to the hydrogen repulsion between the reactants on the confined two-dimensional surface.

Apart from being experimentally and theoretically interesting, tetraphenylene has potential applications in different fields, including supramolecular chemistry, material science, and asymmetric catalysis. Although a wide range of substituted tetraphenylenes have been reported, octaamine-based tetraphenylene derivatives have not been reported because of their instability. Here, stable octaaminotetraphenylene octahydrochloride is synthesized from the bromination of tetraphenylene to octabromotetraphenylene, which is subsequently aminated into octaiminotetraphenylene. Finally, the imino derivative is deprotected to yield octaaminotetraphenylene octahydrochloride.

Molecular assemblies of twisted π molecules of tetraphenylene with long alkoxy chains (1) and tetra[2,3]thienylene with long alkylamide chains (2) or long alkoxy chains (3) and their dielectric properties were investigated. Different degrees of intermolecular interaction of 1–3 afforded different molecular assemblies, including an ordered columnar structure, disordered columnar, and lamellar structures. The introduction of long alkyl chains enabled us to create thermally stable liquid crystalline or liquid states. Temperature-dependent dielectric measurement revealed that the dynamic flipping motion of the tetra[2,3]thienylene core of 3 induced a temperature- and frequency-dependent dielectric anomaly in the neat liquid phase. This flipping motion of the central tetra[2,3]thienylene π core occurred relatively easily in the liquid state with a high degree of freedom of molecular motion.

Tetraphenylene (TPE), characterized as a lipophilic and aggregation-induced-emissive fluorophore, was used to incorporate into an electrostatic self-assembled polyethylenimine-poly(ethylene glycol) (PEI-PEG)/plasmid DNA (pDNA) complexed micelle. The hydrophobic character of TPE appeared to drive a higher degree of condensation of the pDNA payload, which consequently resulted in not only strengthened colloidal stability of the constructed polyplex micelle but also improved biocompatibility by virtue of the elevated PEG crowdedness owing to the TPE-induced collapse of pDNA. These beneficial consequences potentially permitted a larger number of polyplex micelles to be internalized into the cells. PEG segments were designed to enable selective detachment from polyplex micelles in acidic milieu, e.g., the tumor microenvironment, and intracellular endosome compartment, based on the strategic arrangement of acid-responsive cleavable linkage between PEG and PEI. Upon PEG detachment, the exposure of cationic PEI/TPE polyplex was allowed to directly interact with the cell membrane, endosome membrane, and charged intracellular species, thus promoting cell internalization, endosome escape, and the release of the pDNA payload. Of note, this association of cationic PEI/TPE polyplex with the endosomal membrane could be further facilitated with the aid of lipophilic TPE, thereby eliciting pronounced destabilization potency to the endosome membrane and exerting an endosomal escape function. Eventually, the proposed system of these facile strategies, including responsive PEG detachment and functional TPE incorporation, was proven to provide efficient gene expression in the targeted tumors with an appreciable safety profile via systemic administration.

The synthetic strategies towards tetraphenylene derivatives are comprehensively summarized in this review. Recent advances in the functionalized tetraphenylene skeleton for research into their structurally unique properties are described together with their potential applications.

The synthesis and characterization of novel homochiral oligomacrocycle species composed of enantiomerically-pure tetraphenylene were described. Structural studies showed that the macrocyclic molecule possessed a helical chiral cavity, which exhibited unique and efficient recognition affinity towards fullerene C 76 in toluene, as demonstrated by UV–vis titration experiments. The binding results were also interpreted through semi -empirical calculations.

Herein we report a new strategy to construct nano-rings of sp2 carbon by taking advantage of the “C” shape of syn-tetrabenzoheptafulvalene. This strategy led to the successful synthesis of an sp2 carbon nano-ring containing a tetrabenzoheptafulvalene moiety fused with tetraphenylene. However, attempts to synthesize a more strained nano-ring of sp2 carbon using the same strategy only yielded an oxygen-bridged nano-ring with the step of aromatization being unsuccessful. Both the nano-rings were unambiguously characterized by X-ray crystallography.

Diazadithio and diazadiseleno[8]circulenes were synthesized in good yields through a non-pyrolytic cyclization starting from nitrogen-bridged tetraphenylene. Their structures were unambiguously confirmed by X-ray crystallographic analyses. Photophysical, electrochemical and computational investigations of these [8]circulenes suggested their potential applications in inorganic materials.

We report on the bottom-up synthesis of a fully sp2-hybridized nitrogenated three-dimensional microporous graphitic framework (3D-MGF) starting from a highly preorganized, saddle-shaped tetraphenylene derivative under ionothermal reaction conditions. The 3D-MGF showed high stability and a surface area of 928 m2 g−1 along with a narrow pore size distribution. Our approach enabled template-free inclusion of the third dimension into the graphitic frameworks while retaining π-conjugation and conductivity, which was verified by their activity as metal-free electrocatalysts for the hydrogen evolution reaction.

A D-π-A-π-D type of tetraphenylene-coating benzoselenodiazole fluorescence dye with near-infrared emission has been designed and constructed. This dye shows an obvious aggregation-induced-emission behavior. In the solid state, it exhibits a reversible mechanochromism with the changes of near-infrared emission. Furthermore, this dye can be used to track the lysosomes of living cells and images in vivo.

Tetraphenylene-chalcones hybrid derivatives (TPE-T, TPE-B, TPE-N and TPE-Q) have been designed and synthesized, and their optical properties have also been investigated. These new organic fluorophores exhibited relatively large Stokes shifts and absorption extinction coefficients, solvation effects, and some of them also showed moderate AIE effects and solid fluorescence. More significantly, TPE-N shows good fluorescence emission (solution, solid and aggregation states). Single-crystal analysis indicates that molecular stacking patterns are the critical reason affecting the optical properties in solid state. Theoretical calculation explain the fluorescence behaviors because of ICT processes. It has been further demonstrated that these organic fluorophores can be employed for imaging in living cells.

Hydroxytetraphenylenes with rigid conformations are potential candidates for employment as chiral ligands in asymmetric synthesis. Highly diastereo- and enantioselective Darzens reactions between aldehydes and diazo-N,N-dimethylacetamide were found to be catalyzed by a chiral titanium complex formed in situ from Ti(O i Pr)4 and chiral 1,16-dihydroxytetraphenylene, leading to the formation of cis-glycidic amides in moderate to high yields with excellent enantiomeric purities (40–99% yield, up to 99% ee).

A series of β-diketone derivatives bearing tetraphenylene (TPE) moieties were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. All compounds exhibit broad absorption bands between 300 and 450 nm, which are assigned to the 1π-π* transition of the conjugated system mixed intramolecular charge-transfer (ICT) transitions. Meanwhile, the emission of these compounds in solution at room temperature (λ em = 458 ~ 509 nm) can be attributed to the 1π,π*/1ICT state. Introduction of freely rotatable TPE to conventional β-diketone luminophors quenches their light emissions in the solutions, but endows these molecules with aggregation-induced emission (AIE) characteristics in the condensed phase due to the restriction of intramolecular rotation. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these β-diketone derivatives can be tuned by the appended substituents, which would be useful for rational design of AIE compounds with high solid state luminescence performance. Furthermore, these AIE-active compounds exhibited distinct piezofluorochromic properties and switched reversibly upon grinding-fuming. Their photophysical properties have been investigated with the aim to provide a basis for elucidating the structure-property correlations and developing new multi-stimuli responsive luminescent materials.

A highly unsymmetrical trisubstituted tetraphenylene was designed and synthesized as a novel superamolecular scaffold for an unexpected trans-meso tetraphenylene macrocycle, whose structure was unequivocally characterized by an X-ray crystallographic analysis. With the defined and electron-rich aromatic cavity, this macrocycle could be further modified to be a potential host for organic cations with biological interest.

A new strategy for the synthesis of 2-substituted tetraphenylenes through a transition-metal-catalyzed derivatization has been developed. Three types of functionalities, including OAc, X (Cl, Br, I) and carbonyl, were introduced onto tetraphenylene, which allows the easy access to a variety of monosubstituted tetraphenylenes. These reactions could accelerate research on the properties and application of tetraphenylene derivatives.

A new strategy for the synthesis of unsymmetrically disubstituted tetraphenylenes from 2-acetylbiphenylene has been developed via ruthenium-catalyzed C–H functionalization. Four reactions, including alkenylation–cyclization, alkenylation, alkylation, and amidation, were achieved. The reactions provide easy access to a variety of unsymmetrically disubstituted tetraphenylene derivatives, which could accelerate research on the appliation of tetraphenylenes.

Bis-tetraphenylethene-diones (Bis-TPE-diones) can serve as key precursors for the synthesis of blue light-emitting OLED materials. In this paper, four Bis-TPE-diones with different dicarbonyl chains as linkers were elaborately designed for photophysical properties investigation. These Bis-TPE-diones have been facilely synthesized by F-C acylation in one step for the first time. Expensive and harmful reagents as well as harsh reaction conditions were excluded, which make our new method more economical and convenient. The AIE properties, solavatochromism and mechanochromism of the Bis-TPE-diones have also been carefully studied. The Bis-TPE-diones exhibited notable AIE properties and their maximum fluorescence in THF can be turned on by low water fractions (fw, 10%–40%). The fw to turn on the maximum fluorescence are closely associated with the dicarbonyl chain linkers in the Bis-TPE-diones as the following sequence: conjugate chain (fumaryl, fw = 10%)

A palladium-catalyzed double Ullmann coupling reaction for the preparation of tetraphenylenes has been developed. With this protocol, twelve tetraphenylene derivatives were synthesized from the corresponding 2,2′-diiodobiaryls directly with the yields ranging from 13–51 %. Insights into the mechanism of these palladium-catalyzed double coupling reactions are discussed, and the findings are expected to increase the level of understanding of palladium-catalyzed formation of carbon–carbon bonds within rigid molecular frameworks.

A tetramesityl derivative of hitherto unknown tetracyclopenta[def,jkl,pqr,vwx]tetraphenylene (TCPTP), which is a potential tetraradicaloid hydrocarbon, was synthesized. Theoretical calculations based on spin-flip time-dependent density functional theory predict that the closed-shell D2h form of TCPTP is more stable than the open-shell D4h form with its slightly tetraradical character. The tetramesityl derivative (Mes)4 -TCPTP exhibits remarkable antiaromaticity as a result of the peripheral 20-π-electron circuit, which causes an absorption maximum at a long wavelength and a small HOMO-LUMO gap. In solution, (Mes)4 -TCPTP most likely adopts rapidly equilibrating D2h structures that interconvert via the D4h transition state. X-ray crystallographic analysis showed (Mes)4 -TCPTP as an approximate D2h structure.

In this work, several new compounds containing tetraphenylene (TPE) units and dimesitylboron groups were synthesized through Sonogashira coupling reaction. The compounds showed aggregation induced emission (AIE), emitted different colors and gave a relatively high quantum yield of fluorescence in the solid state. Two of the compounds demonstrated potential application in data storage, and one molecule also displayed potential value in biological fluorescence cell imaging.

A targeted cathepsin B-activatable gemcitabine prodrug with caspase-3 specific light-up tetraphenylene (TPE) as an apoptotic probe based on aggregation-induced emission (AIE) properties was designed for in situ self-therapeutic monitoring of pancreatic cancer cells.

Developments of tetraphenylene chemistry in our laboratories (Shanghai and Hong Kong) since 2009 are summarized. The properties and new applications of the structurally unique tetraphenylene derivatives are described in the context of helical macrocycles

A rationally designed 2,3,10,11-tetrahydroxytetraphenylene (1) has been synthesized. Employing 1 as a building block, a structurally novel tweezer-like host 2 containing dibenzo-24-crown-8 moieties has been prepared. Host 2 showed excellent molecular-recognition ability toward paraquat (=1,1′-dimethyl-4,4′-bipyridinium dichloride) derivative 3a to form a 1 : 1 stable complex in solution.

A new strategy for the synthesis of 2-substituted tetraphenylenes through a transition-metal-catalyzed derivatization has been developed. Three types of functionalities, including OAc, X (Cl, Br, I) and carbonyl, were introduced onto tetraphenylene, which allows the easy access to a variety of monosubstituted tetraphenylenes. These reactions could accelerate research on the properties and application of tetraphenylene derivatives.

A palladium-catalyzed double Ullmann coupling reaction for the preparation of tetraphenylenes has been developed. With this protocol, twelve tetraphenylene derivatives were synthesized from the corresponding 2,2′-diiodobiaryls directly with the yields ranging from 13–51 %. Insights into the mechanism of these palladium-catalyzed double coupling reactions are discussed, and the findings are expected to increase the level of understanding of palladium-catalyzed formation of carbon–carbon bonds within rigid molecular frameworks.

This paper is concerned with the syntheses of 1,8,9,16-tetrahydroxytetraphenylene derivatives and their applications as Bronsted base organocatalysts for [4+2] cycloaddition between anthrone and maleimides. The structural modifications of the catalysts and their related catalytic properties are described and discussed in details.

Compounds with highly annelated, chiral {pi}-systems, such as tetraphenylenes and [n]helicenes, are known to possess strong chiral properties and high configurational stability, which are prerequisites for many chiral materials. This account describes the unfolding story about our research on the synthesis and X-ray crystallographic characterization of functionalized nonracemic tetraphenylenes and helical {beta}-oligothiophenes, as well as related [n]helicene derivatives.

1,4,5,8,9,16-Hexahydroxytetraphenylene (5) was synthesized by an iodobenzene diacetate-mediated phenolic oxidation. Enantiopure forms of 1,4,5,8,9,16-hexahydroxytetraphenylenes [(S,R,S)-5 and (R,S,R)] were successfully synthesized either by using (S,S)-and (R,R)-1,8,9,16-tetramethoxytetraphenylenes [(S,S)-7 and (R,R)-7] as starting materials or by direct resolution of 1,4,5,8,9,16-hexahydroxytetraphenylene (5).

Palladium-catalyzed double-Suzuki–Miyaura couplings between cyclic dibenziodoniums and arylboronic acids have been developed. As such, a wide range of o-tetraaryls were synthesized in good to excellent yields of 22–94%. Furthermore, tetraphenylene was prepared in 21% isolated yield with 2,2′-biphenyldiboronic acid by using this method.

Compound (I), a derivative of the hitherto unknown title compound which is a potential tetraradicaloid hydrocarbon, is synthesized in five steps starting from a known polycyclic tetracarboxylic acid (synthetic pathway not shown).

A type of soluble and thermally stable semiladder polyphenylenes containing carbazole moieties (SLPFCs) have been prepared with a facile and short synthetic route. The full characterizations of structures and properties as well as the performances of electroluminescence devices of the new polymers are presented. The conjugated backbone of the SLPFCs contained three kinds of constituents: fluorene, ladder-type tetraphenylene, and ladder-type hexaphenylene. The SLPFCs exhibit pure-blue fluorescence (λmax = 445 nm) with high efficiency up to 90% in solution. Electrochemical studies indicate that the introduction of carbazole moieties raises the HOMO energy levels. Furthermore, the single-layer light-emitting devices using the SLPFCs as the active layer show pure-blue emission (λmax = 447 nm, CIE coordinates: 0.15, 0.05) with maximum luminescence of 5500 cd/m2 and maximum luminance efficiency of 0.556 cd/A. The attractive properties exhibited by the new semiladder polymers establish them as good candidates ...