Triptycene Core Research Articles

Design, Synthesis, and Anticancer Activity of Triptycene-Peptide Hybrids that Induce Paraptotic Cell Death in Cancer Cells.

We report on the design and synthesis of triptycene-peptide hybrids (TPHs), 5, syn-6, and anti-6, which are conjugates of a triptycene core unit with two or three cationic KKKGG peptides (K: lysine and G: glycine) through a C8 alkyl chain. It was discovered that syn-6 and anti-6 induce paraptosis, a type of programmed cell death (PCD), in Jurkat cells (leukemia T-lymphocytes). Mechanistic studies indicate that these TPHs induce the transfer of Ca2+ from the endoplasmic reticulum (ER) to mitochondria, a loss of mitochondrial membrane potential (ΔΨm), tethering of the ER and mitochondria, and cytoplasmic vacuolization in the paraptosis processes.

Electrophilic Substitution of Asymmetrically Distorted Benzenes within Triptycene Derivatives.

Herein, we disclose a unique directing effect of 9-substituted triptycenes in electrophilic substitution to achieve the regioselective functionalization of the triptycene core. The Hirshfeld population analysis was adopted to predict the selectivity in electrophilic substitution. TMS and t-Bu groups were found to considerably accelerate the reaction at C2 positions to produce C3-symmetric isomers. Correlation between distortion and charge distribution within benzene rings was systematically examined.

Proving Triptycene Homoconjugation with the Same Chromophore but Different Connectivity to the Core

Homoconjugation is a phenomenon discussed for various π-systems where classical conjugation is broken by e.g. methylene units but still a stabilization by electronic communication exists. In this respect, triptycene with its rigid C3 symmetric geometry is an ideal scaffold to study this phenomenon. Although several studies based on triptycene strengthen the hypothesis of homoconjugation, in all described cases the electronic communication through space relies on different π-blades. Here, two triptycenes are presented having the exact same π-extended chromophore, but differently annulated to the bicyclic core. Both compounds were investigated by spectroscopic as well as computational means and compared with the corresponding model compound, elucidating the influence of the attachment site to the triptycene core on potential homoconjugation.

Non-planar Boron Lewis Acids Taking the Next Step: Development of Tunable Lewis Acids, Lewis Superacids and Bifunctional Catalysts

Although boron Lewis acids commonly adopt a trigonal planar geometry, a number of compounds in which the trivalent boron atom is located in a pyramidal environment have been described. This review will highlight the recent developments of the chemistry and applications of non-planar boron Lewis acids, including a series of non-planar triarylboranes derived from the triptycene core. A thorough analysis of the properties and of the influence of the pyramidalization of boron Lewis acids on their stereoelectronic properties and reactivities is presented based on recent theoretical and experimental studies.1 Non-planar Trialkylboranes2 Non-planar Alkyl and Aryl-Boronates3 Non-planar Triarylboranes and Alkenylboranes3.1 Previous Investigations on Bora Barrelenes and Triptycenes3.2 Recent Work on Boratriptycenes from Our Research Group4 Applications of Non-planar Boranes4.1 Non-planar Alkyl Boranes and Boronates4.2 Non-planar Triarylboranes (Boratriptycenes)5 Other Non-planar Group 13 Lewis Acids6 Further Work and Perspectives

Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids.

Suitably designed quinones and quinols are promising modules for the programmed construction of ordered redox-active molecular solids. To explore this potential, we have synthesized compounds 1-4, in which multiple 1,2-benzoquinone and 1,2-quinol units are attached to a triptycene core. The resulting molecules have topologies that disfavor efficient packing, and structural studies show that they crystallize to form open networks held together by characteristic attractive intermolecular forces, including O-H···O hydrogen bonds, C-H···O interactions, π-stacking, and dipolar interactions. Remarkably, the resulting solids are permeable and can undergo reversible redox reactions without loss of crystallinity. Our work may thereby help lead to the design of robust carbon-based batteries with electrodes derived from quinones, quinols, and other redox-active molecules abundantly produced by nature.

A New Hole Transport Material for Efficient Perovskite Solar Cells With Reduced Device Cost

To realize commercialization of perovskie solar cell (PVSC) technology, it is essential to reduce the device costs while maintaining high power conversion efficiencies (PCEs). So far, the high cost of the most commonly used hole selective material, 2,2′,7,7′‐Tetrakis (N,N‐di‐p‐methoxyphenylamino)‐9,9′‐spirobifluorene (spiro‐OMeTAD), for high‐PCE PVSCs presents a significant obstacle for device cost reduction. In this work, the synthesis and characterization of a new spiro‐OMeTAD derivative hole selective material, 2,6,14‐tris(5′‐(N,N‐bis(4‐methoxyphenyl)aminophenol‐4‐yl)‐3,4‐ethylenedioxythiophen‐2‐yl)‐triptycene (TET) is reported. TET features a three‐dimensional structure consisting of a triptycene core and triarylamine arms linked by 3,4‐ethylenedioxythiophene, facilitating efficient hole transport. Planar PVSCs using TET hole selective layers (HSLs) achieved high fill factors of over 81% and steady‐state efficiencies of up to 18.6%, comparable with that (19.0%) of PVSC using spiro‐OMeTAD HSL. Importantly, the hereby reported efficient PVSCs can be produced with very thin TET HSLs (about 30 nm). Considering the lower laboratory synthesis and purification cost ($123 vs. $500 g−1) and thinner HSL (30 vs. 200 nm), the cost for TET on a unit area of one device is 25 times lower than that for high‐purity spiro‐OMeTAD. The device with TET HSL shows good stability under continuous illumination. Therefore, this work makes a significant step forward toward the commercialization of the emerging PVSC technology.

Facile Synthesis of Electroactive and Electrochromic Triptycene Poly(ether-imide)s Containing Triarylamine Units via Oxidative Electro-Coupling.

Two bisimide compounds, TPA–TPDI and NPC–TPDI, consisting of a triptycene core and two triphenylamine (TPA) or N-phenylcarbazole (NPC) end groups were successfully synthesized by the condensation reactions from 1,4-bis(3,4-dicarboxyphenoxy)triptycene dianhydride with 4-aminotriphenylamine and N-(4-aminophenyl)carbazole, respectively. These two monomers could polymerize electrochemically via the oxidative coupling reactions of triarylamine units. The electrochemical and spectroelectrochemical properties of the electro-generated triptycene poly(ether-imide)s (TPA–TPPI and NPC–TPPI) were studied. Both polymers have two colored oxidation states, and TPA–TPPI showed better electrochromic performance than NPC–TPPI.

Rigid Nonfullerene Acceptors Based on Triptycene-Perylene Dye for Organic Solar Cells.

Three kinds of nonconjugated rigid perylene bisimide (PBI) derivatives based on a triptycene core were designed, synthesized and characterized. The unique three-dimensional (3D) conformation of triptycene could enable formation of polymer with the favorable morphology for organic polymer solar cells (PSCs) by relieving the self-aggregation of rigid PBI units. The low-lying LUMO energy levels of these compounds demonstrated that they are very suitable for use as acceptors in organic solar cells. A higher power conversion efficiency (PCE) of 6.15 % was obtained for the blend film using the compound with two PBI units (T-2) as the acceptor and commercial poly[[4,8-bis[5-(2-ethylhexyl)thiophene-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophenediyl]] (PCE-10) as the electron donor.

A perylene diimide electron acceptor with a triptycene core for organic solar cells

A novel nonplanar 3D acceptor material for organic solar cells composed of three perylene diimide units and a triptycene core is synthesized and characterized.

Synthesis of 9-Substituted Triptycene Building Blocks for Solid-Phase Diversification and Nucleic Acid Junction Targeting.

Triptycenes have been shown to bind nucleic acid three-way junctions, but rapid and efficient methods to diversify the triptycene core are lacking. An efficient synthesis of a 9-substituted triptycene scaffold is reported that can be used as a building block for solid-phase peptide synthesis and rapid diversification. The triptycene building block was diversified to produce a new class of tripeptide-triptycenes, and their binding abilities toward d(CAG)·(CTG) repeat junctions were investigated.

Preparation of Tri‐ and Hexasubstituted Triptycene Synthons by Transition Metal Catalyzed Cross‐Coupling Reactions for Post‐Modifications

AbstractRational building strategies and appropriate synthons have been developed for the use of triptycene as a rigid presenting scaffold. Palladium‐catalyzed cross‐coupling reactions, such as Sonogashira and Suzuki couplings, were used to install a variety of different synthetic handles around the triptycene periphery in a high‐yielding and controlled manner. These triptycene molecular handles were investigated for their potential in the construction of molecular arrays with defined spatial orientation e.g., for host‐guest interactions or drug delivery systems. Such molecular synthons afforded expansion from the triptycene core by employing arm extension to increase the internal free volume characteristic of triptycene scaffolds for such applications. In addition, a range of mesogenic and glycosyl triptycene derivatives were achieved as a synthetic proof of concept for future work on potential drug delivery systems.

Synthesis, Structure, and Complexation Properties of a C3-Symmetrical Triptycene-Based Anion Receptor: Selectivity for Dihydrogen Phosphate.

A new anion binding motif based on triptycene core has been synthesized from 2,7,14-trinitrotriptycene. Its well-defined binding pocket allowed for the selective recognition and sensing of dihydrogen phosphate in DMSO-d(6) + 0.5% H(2)O.

1,4-Selective Diels–Alder Reaction of 9,10-Diethynylanthracene with 3,6-Difluorobenzyne

Abstract Diels–Alder reaction of 9,10-bis(3-hydroxy-3-methyl-1-butynyl)anthracene with 3,6-difluorobenzyne yields the naphthobarrelene derivative via 1,4-addition of difluorobenzyne in a higher yield than the 9,10-adduct having a triptycene core. The DFT calculations revealed that the intermediate for the former reaction is stabilized more significantly by attractive interaction between a fluorine atom at the benzyne ring and a hydrogen atom at the anthracene ring.

Photochromic dithienylethene-branched triptycene hybrids

Dithienylethene and triptycene both have controllable structure and versatile performances. In this study, a series of triptycene hybrids decorated different number of dithienylethene units have been developed for photochromic switch. The synthetic process is facile and efficient and all new compounds were clearly characterized by 1H NMR, 13C NMR and HRMS. Their photochromism and spectroscopic properties have been investigated in dichloromethane and tetrahydrofuran. The result revealed that the multi-dithienylethene units grafted to triptycene behaved independently and showed distinctive solvent-dependent photochromism in chloride solvents, which probably due to the introduction of controlled spatial arrangement of triptycene core. These distinctive characteristics might be potential used for high-density multicomponent switches and detection of chloride solvents.

Large area synthesis of a nanoporous two-dimensional polymer at the air/water interface.

We present the synthesis of a two-dimensional polymer at the air/water interface and its nm-resolution imaging. Trigonal star, amphiphilic monomers bearing three anthraceno groups on a central triptycene core are confined at the air/water interface. Compression followed by photopolymerization on the interface provides the two-dimensional polymer. Analysis by scanning tunneling microscopy suggests that the polymer is periodic with ultrahigh pore density.

Synthesis, characterization and DNA interaction studies of new triptycene derivatives.

A facile and efficient synthesis of a new series of triptycene-based tripods is being reported. Using 2,6,14- or 2,7,14-triaminotriptycenes as synthons, the corresponding triazidotriptycenes were prepared in high yield. Additionally, we report the transformation of 2,6,14- or 2,7,14-triaminotriptycenes to the corresponding ethynyl-substituted triptycenes via their tribromo derivatives. Subsequently, derivatization of ethynyl-substituted triptycenes was studied to yield the respective propiolic acid and ethynylphosphine derivatives. Characterization of the newly functionalized triptycene derivatives and their regioisomers were carried out using FTIR and multinuclear NMR spectroscopy, mass spectrometry, and elemental analyses techniques. The study of the interaction of these trisubstituted triptycenes with various forms of DNA revealed interesting dependency on the functional groups of the triptycene core to initiate damage or conformational changes in DNA.

Novel hole transporting materials based on triptycene core for high efficiency mesoscopic perovskite solar cells

Three novel hole-conducting molecules (T101, T102 and T103) based on a triptycene core have been synthesized using short routes with high yields. The optical and electrochemical properties were tuned by modifying the functional groups, through linking the triptycene to diphenylamines via phenyl and/or thienyl groups. The mesoporous perovskite solar cells fabricated using T102 and T103 as the hole transporting material (HTM) showed a power conversion efficiency (PCE) of 12.24% and 12.38%, respectively, which is comparable to that obtained using the best performing HTM spiro-OMeTAD. The T102 based device showed higher fill factor (69.1%) and Voc (1.03 V) than the spiro-OMeTAD based device (FF = 63.4%, Voc = 0.976 V) whereas the T103 based device showed comparable Jsc (20.3 mA cm−2) and higher Voc (0.985 V) than the spiro-OMeTAD (Jsc = 20.8 mA cm−2) based cell.

Synthesis and characterization of triptycene based tripods and design of a metallasupramolecular cage

Synthesis and characterization of four new tripodal linkers each with a central triptycene unit and pendant pyridine unit have been reported. These tripods have flexible arms due to the presence of amide linkages that bridge the peripheral pyridine units and central triptycene core. Self-assembly of one of the tripods with Pt(II) based ditopic acceptor unit is the first example of a truly supramolecular cage based on a triptycene tecton. Additionally, this metallacage also represents the unique example of a Pt(II) based trigonal bipyramidal (TBP) cage containing amide functionality.

Tetrathiafulvalene-functionalized triptycenes: synthetic protocols and elucidation of intramolecular Coulomb repulsions in the oxidized species

A large selection of triptycenes functionalized with tetrathiafulvalene (TTF) units as well as triptycenes containing extended TTFs as a part of the triptycene core have been synthesized utilizing new triptycene di- and tetraaldehydes as well as bis-, tetrakis- and hexakis(bromomethyl) derivatives. The largest scaffold contains a total of 12 TTFs around the central triptycene core. From spectroelectrochemical and chemical oxidation studies, we have elucidated the extent to which an increasing number of electrostatic interactions among oxidized TTF units exert an influence on the absorption characteristics.