Tp Moieties Research Articles

An AIEgen and Iodine Double-Ornamented Platinum(II) Complex for Bimodal Imaging-Guided Chemo-Photodynamic Combination Therapy.

Real-time biodistribution monitoring and enhancing the therapeutic efficacy of platinum(II)-based anticancer drugs are urgently required to elevate their clinical performance. Herein, a tetraphenylethene derivative (TP) with aggregation-induced emission (AIE) properties and an iodine atom are selected as ligands to endow platinum (II) complex TP-Pt-I with real-time in vivo self-tracking ability by fluorescence (FL) and computerized tomography (CT) imaging, and improved anticancer efficacy by the combination of chemotherapy and photodynamic therapy. Especially, benefiting from the formation of a donor-acceptor-donor structure between the AIE photosensitizer TP and Pt-I moiety, the heavy atom effects of Pt and I, and the presence of I, TP-Pt-I displayed red-shifted absorption and emission wavelengths, enhanced ROS generation efficiency, and improved CT imaging capacity compared with the pristine TP and the control agent TP-Pt-Cl. As a result, the enhanced intratumoral accumulation of TP-Pt-I loaded nanoparticles is readily revealed by dual-modal FL and CT imaging with high contrast. Meanwhile, the TP-Pt-I nanoparticles show significantly improved tumor growth-inhibiting effects on an MCF-7 xenograft murine model by combining the chemotherapeutic effects of platinum(II) and the photodynamic effects of TP. This self-tracking therapeutic complex thus provides a new strategy for improving the therapeutic outcomes of platinum(II)-based anticancer drugs.

A novel triptycene-terminated polymer used as the gas chromatographic stationary phase towards organic acidic/basic analytes and isomers

This work presents a novel strategy for engineering a GC stationary phase with high selectivity, inertness and thermal stability by introducing the 3D π-rich TP moieties to the terminals of a polar chain polymer. Herein, we provide the first example, i.e., a new TP-terminated polycaprolactone polymer (TPP) as the stationary phase for GC analyses. As demonstrated, the TPP column achieved distinctly improved inertness to fatty acids and aldehydes, and dramatically enhanced thermal stability (about 100 °C higher) over the PCL column. Also, the TPP column exhibited high resolving capability towards the positional isomers of phenols, anilines and alkylated/halobenzenes and showed good potential in detecting minor impurities in chemical products. Importantly, the proposed strategy is facile, feasible and generally applicable to analogous polymers.

Molecular dynamics of four-coordinate carbene-Cu(I) complexes employing tris(pyrazolyl)borate ligands

A series of three- and four-coordinate Cu(I) complexes was prepared employing a N-heterocyclic carbene and various scorpionate trispyrazolylborate (Tp) ligands. The NMR spectra of the four-coordinated complexes suggest C3 symmetry for the Tp ligands despite the asymmetric scorpionate η3-binding fashion observed by single crystal X-ray diffraction. Variable temperature (VT) 1H and 13C NMR spectroscopy was used to elucidate the dynamic process that equilibrates the different structural isomers. We report that the rapid exchange of the pyrazoles in the Tp ligand was hampered but not fully inhibited at −88 °C. Lastly, we show how the electrophilicity of the carbene and the hapticity of the Tp moiety both control the photophysics: more electrophilic carbenes red-shift the luminescence and bulkier Tp suppress modes of nonradiative decay (knr).

Influence of main chain on the phase behaviors of side‐chain liquid‐crystalline polymers with triphenylene mesogens of long alkyl tail substituents

ABSTRACTA series of side‐chain liquid‐crystalline polymers (SCLCPs) containing triphenylene mesogen, in which the long alkyl tail Tp connected directly with main chain, were synthesized successfully. The chemical structures of the monomers were confirmed by 1H NMR and mass spectrometry. The phase behaviors of polymers were investigated by a combination of techniques, including DSC, POM, 1D/2D WAXD, and SAXS. The experimental results suggested that the type of main chain played an important role in the LC phase structures of these polymers. Because of the steric effects of side chains and the coupling effects between the Tp moieties and the main chains, all the polymers exhibited columnar phase. However, the SCLCPs with poly(vinyl benzene methyl ether) or polynorbornene backbone displayed hexagonal columnar phase, while those with polyacrylate or polymethacrylate backbone presented columnar nematic phase, and the one with poly(vinyl benzoate) main chain showed rectangular columnar phase. Moreover, the clearing temperatures (Ti) changed with change in main chain. Especially, the Ti of the SCLCP with polymethacrylate backbone was above 300 °C. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 754–766

Effects of main chain and acceptor content on phase behaviors of hydrogen-bonded main-chain/side-chain combined liquid crystalline polymers

Main-chain/side-chain combined liquid crystalline polymers (MCSCLCPs) are usually difficult to synthesize and their degrees of polymerization are relatively low, which bring difficulties in studying their structure–property relationships. In order to solve this problem, we prepared a new series of MCSCLCPs containing mesogen-jacketed liquid crystalline polymer (MJLCP) main chains via hydrogen-bonding (H–B). A pyridine derivative with a triphenylene (Tp) unit is the H–B acceptor. In addition to the temperature dependence, the phase behavior of the resulting complex is strongly influenced by the content of the H–B acceptor and the rigidity of the side-chain core of the MJLCP. The resulting complexes exhibit different phase structures: (1) a columnar nematic phase or a smectic A (SmA) phase formed by the supramolecular MJLCP chain as a whole; (2) hierarchical nanostructures including a hexagonal columnar phase or a SmA phase of the whole polymer chain plus a discotic nematic phase associated with the Tp moieties.

Self-Assembly of Four-Claw Discotic Mesogenic Molecules: Influence of Core on Chirality

The morphology of self-assembled monolayers determined by molecular structure and involved interactions plays a crucial role in their properties. Herein, we report a study on 2D self-assembly of two kinds of triphenylene-submitted discotic mesogenic species, which have similar four TP moieties with alkyne spacer but different rigid aromatic cores pyrene and carbazole. Two types of stable periodic long-ranged supramolecular networks on the highly oriented pyrolytic graphite surface have been visualized via high-resolution scanning tunneling microscopy technique. A comparative study reveals how the aromatic core of molecular building blocks affects achiral and chiral arrangement of discotic molecule on surface. The asymmetry backbone results in molecular orientation and varied van der Waals forces between molecule–molecule and molecule–substrate. Our results demonstrate that design of functional molecules plays an important role in the construction of 2D supramolecular assembly possessing desirable structur...

Synthesis and liquid crystalline behavior of side chain liquid crystalline polymers containing triphenylene discotic mesogens with different length flexible spacers

A series of side chain liquid crystalline polymers (SCLCPs) containing triphenylene (Tp) units in the side chains, denoted as PMTS (without spacer) and PMTnS (n = 2, 3, 4, 6, which is the number of the methylene units between the main chain and Tp moieties in the side chains), with different lengths of spacers were synthesized through conventional free radical polymerization. The chemical structures of the monomers were confirmed by 1H/13C-NMR, and the phase behaviors were examined by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide-angle X-ray diffraction (1D and 2D WAXD). The molecular characterization of the polymers was performed with 1H-NMR, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D and 2D WAXD. The results showed that the length of spacer has significant effects on the LC phase behavior of polymers. For PMTS and PMT2S, they displayed the columnar phase developed by the Tp moieties and the main chain as a whole due to the strong coupling effect of the Tp moieties and the main chain. For the PMT3S, PMT4S and PMT6S, they formed the symmetry hexagonal columnar (ΦH) phase owing to the decoupling effect. All of these indicated that the “decoupling effect” or “coupling effect” depended on the length of spacers, leading to the different LC phase formation mechanism.

Influence of the spacer and molecular weight on the phase behavior of side-chain liquid crystalline polymers containing triphenylene discotic mesogen units as side groups

Two series of side chain liquid crystalline polymers (SCLCPs), poly{[3,6,7,10,11-pentakis(hexyloxy)-2-oxytriphenylene]methacrylate} (PMTS with no flexible spacer) and poly{6-[3,6,7,10,11-pentakis(hexyloxy)-2-oxytriphenylene]hexyl methacrylate} (PMT6S with 6 methylene units as a flexible spacer), with different molecular weights (Mn) and low molecular weight distributions have been successfully synthesized via atom transfer radical polymerization (ATRP). The phase behavior of the polymers has been investigated by a combination of techniques, including differential scanning calorimetry (DSC), polarized optical microscopy (POM), and 1D and 2D wide-angle X-ray diffraction (1D and 2D WXRD). The experimental results revealed that the LC phase structures of PMTS were found to be strongly Mn dependent. The PMTS polymers were amorphous when the Mn was lower than a critical Mn of approximately 2.03 × 104 g mol−1. When the Mn was higher than this critical value, the PMTS polymers displayed a rectangular (ΦR) columnar phase. On the contrary, the PMT6S polymers displayed a higher symmetry hexagonal (ΦH) columnar phase, which was independent of Mn. A comparison between PMTS and PMT6S suggested that the spacer plays an important role in the construction of liquid crystalline (LC) ordered structures. For the former, PMTS polymers without the spacer formed rectangular ΦR phases caused by the Tp moieties and the main chain as a whole, due to the strong coupling effect between the Tp moieties and the main chain. For the latter, PMT6S polymers with 6 methylene units as a flexible spacer gave a higher symmetry ΦH phase owing to the decoupling and self-organization of the Tp moieties.

Ordered nanostructures at two different length scales mediated by temperature: A triphenylene‐containing mesogen‐jacketed liquid crystalline polymer with a long spacer

ABSTRACTA mesogen‐jacketed liquid crystalline polymer (MJLCP) containing triphenylene (Tp) moieties in the side chains with 12 methylene units as spacers (denoted as PP12V) was synthesized. Its liquid crystalline (LC) phase behavior was studied with a combination of solution 1H NMR, solid‐state NMR, gel permeation chromatography, thermogravimetric analysis, polarized light microscopy, differential scanning calorimetry, and one‐ and two‐dimensional wide‐angle X‐ray diffraction. By simply varying the temperature, two ordered nanostructures at sub‐10‐nm length scales originating from two LC building blocks were obtained in one polymer. The low‐temperature phase of the polymer is a hexagonal columnar phase (ΦH, a = 2.06 nm) self‐organized by Tp discotic mesogens. The high‐temperature phase is a nematic columnar phase with a larger dimension (a′ = 4.07 nm) developed by the rod‐like supramolecular mesogen—the MJLCP chain as a whole. A re‐entrant isotropic phase is found in the medium temperature range. Partially homeotropic alignment of the polymer can be achieved when treated with an electric field, with the polymer in the ΦH phase developed by the Tp moieties. The incorporation of Tp moieties through relatively long spacers (12 methylene units) disrupts the ordered packing of the MJLCP at low temperatures, which is the first case for main‐chain/side‐chain combined LC polymers with MJLCPs as the main‐chain LC building block to the best of our knowledge. The relationship of the molecular structure and the novel phase behavior of PP12V has implications in the design of LC polymers containing nanobuilding blocks toward constructing ordered nanostructures at different length scales. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 295–304

Palladium‐Catalyzed Direct C–H Arylation of Thieno[3,4‐b]pyrazines: Synthesis of Advanced Oligomeric and Polymeric Materials

AbstractThe first examples are reported of an efficient regioselective direct C–H arylation of thieno[3,4‐b]pyrazine (TP) and its 2,3‐dimethyl derivative with bromoalkylthiophenes (BATs), under Heck experimental conditions using Pd(OAc)2/Bu4NBr as the catalytic system, giving rise to a variety of valuable aryl‐substituted thienopyrazines. The obtained results suggested that the 2‐position of the TP moiety is less reactive towards C–H arylation than the 5‐ and 7‐positions. Moreover, the 3‐position of the TP moiety showed almost no significant reactivity when all other positions were arylated. The C–H arylation of 2,3‐dimethyl‐TP with an excess amount of BATs proceeded smoothly, affording the corresponding diarylated thienopyrazine derivatives in excellent yields, without any additional products. Compared to usual cross‐coupling reactions, the present synthetic methodology has been used to prepare interesting donor–acceptor π‐conjugated polymeric materials in a facial manner in a simple way. Microwave‐assisted polymerization proved to be efficient for obtaining reasonable molecular weight copolymers ranging from 18.8 to 24.3 kg mol–1. Incorporating the thienopyrazine unit into polyhexylthiophene chains affected the photophysical and electrochemical properties. The optical band gaps were estimated to be in the range of 1.63–1.06 eV. All copolymers exhibited a diffraction peak at around 2θ = 5.72° corresponding to a d spacing of 15.43 Å, which was assigned to an interchain spacing between polymer main chains similar to that found in P3HT. Moreover, a peak around 2θ = 23.09 (3.84 Å) was also observed and is believed to be related to π‐π stacking of the polymer backbones.

Competition and Promotion between Two Different Liquid-Crystalline Building Blocks: Mesogen-Jacketed Liquid-Crystalline Polymers and Triphenylene Discotic Liquid Crystals

Mesogen-jacketed liquid-crystalline polymers (MJLCPs) containing two triphenylene (Tp) units in the side chains, denoted as PPnV (n = 3 or 6, which is the number of the methylene units between the terephthalate core and Tp moieties in the side chains), were synthesized through conventional free radical polymerization, and the phase behaviors of these new combined main-chain/side-chain liquid-crystalline (LC) polymers were investigated. The chemical structures of the monomers were confirmed by elemental analysis, high-resolution mass spectrometry, and 1H/13C NMR. The molecular characterizations of the polymers were performed with 1H NMR, gel permeation chromatography, and thermogravimetric analysis. LC behaviors of the polymers were investigated by differential scanning calorimetry (DSC), polarized light microscopy, and wide-angle X-ray diffraction (WAXD). Both polymers exhibit excellent thermal stabilities. DSC and WAXD results indicate that covalently incorporating Tp discotic liquid crystals has a treme...

Solvent-dependent 2D-coordination polymers of Cu(I) containing a bridging triazolopyrimidine ligand

Two 2D-polymers of Cu(I), [Cu2(μ-tp)(CH3CN)(μ-I)(μ3-I)]n (1) and [Cu2(μ-tp)(μ3-I)2]n (2), both obtained from the reaction between copper iodide and 1,2,4-triazolo[1,5-a]pyrimidine (tp) in the presence of KI are described. While in compound 1, tp acts as bridging ligand via N1 and N3 between chair-like [Cu4I4] units, in compound 2, tp moieties are placed at both sides of a [CunIn] kinked layer, displaying also a bridging mode but, in this case, through its atoms N3 and N4. These structural differences between both compounds seem to be due to the solvent of crystallization, being acetonitrile for 1 and water for 2. These polymers are the first examples of Cu(I) compounds based on the nucleobase-analog ligand tp.

Effects of Acceptors on the Electronic and Optoelectronic Properties of Fluorene‐Based Donor–Acceptor–Donor Copolymers

AbstractIn this study, four fluorene‐based conjugated copolymers were synthesized to explore the acceptor effects on the electronic and optoelectronic properties. The studied polymers were poly{[2,7‐(9,9‐dihexylfluorene)]‐alt‐[2,2′:5,2″‐terthiophene]} (PFTT) and its derivatives of poly{[2,7‐(9,9′‐dihexylfluorene)]‐alt‐[2,3‐dimethyl‐5,7‐dithien‐2‐yl‐quinoxaline]} (PFDDTQ), poly{[2,7‐(9,9′‐dihexylfluorene)]‐alt‐[4,7‐dithien‐2‐yl‐2,1,3‐benzothiadiazole]} (PFDTBT), and poly{[2,7‐(9,9′‐dihexylfluorene)]‐alt‐[2,3‐dimethyl‐5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine]} (PFDDTTP) with the acceptors of quinoxaline (Q), 2,1,3‐benzothiadiazole (BT), and thieno[3,4‐b]pyrazine (TP), respectively. The order of the band gap was PFDTTP < PFDTBT < PFDDTQ < PFTT, which was on the reverse trend of emission maximum and field‐effect transistor (FET) mobility. The strong acceptor strength of the TP moiety and coplanar backbone in PFDTTP resulted in the highest intramolecular charge transfer (ICT) among the four polymers. The FET mobility of PFDTTP could be varied by two orders of magnitude through the solvent quality. The present study suggested the importance of the acceptor structure on the electronic and optoelectronic properties of semiconducting polymers.magnified image

Synthesis, crystal structure and helical ladder-like assembly of a novel terephthalato-bridged binuclear Cu(II) complex: First report on terephthalate bridging under tetraaza macrocyclic environment

Single crystal X-ray study on a novel terephthalato-(μ 2-tp)-bridged binuclear Cu(II) tetraaza macrocyclic complex, [Cu 2(dinemac) 2(tp)(ClO 4) 2], reveals that the syn– anti disposition of two NO 2 groups in the individual dinemac ligand and consequent intermolecular H-bonding between the two successive binuclear entities on both sides results a supramolecular R 2 2 (34) synthon in (0 1 1) plane which on further propagation in the same sequence renders two single strand helices connected via tp moiety results a 3-D supramolecular helical ladder-like assembly.

Exciplex Emission of Carbazole–Terephthalate Cyclophane and Its Application as a Fluorescent Probe for Local Polarity of Solvents

Abstract Photophysical properties of carbazole–terephthalate cyclophane (Cz–TP) were studied. The absorption spectra of Cz–TP in various solvents were slightly broadened due to the distortion of the carbazole (Cz) moiety and became similar to that of a reference compound of carbazole–benzene cyclophane (Cz–Bz). The absorption spectrum and the peak wavelengths of Cz–TP were insensitive to the solvent polarity. These findings show that there is transannular π–π electronic interaction between the Cz and TP moieties but that the charge transfer interaction from the Cz to TP moieties is small in the ground state. On the other hand, the emission spectrum was broad, structureless, and red-shifted compared with that of the reference compound. The peak wavelength of the emission was shifted to a longer wavelength with increases in the dielectric constant of solvents. The peak shift was quantitatively explained by the Lippert–Mataga formula. Therefore, we conclude that the broad emission is due to the intramolecular exciplex in Cz–TP. The dielectric constant of 2-methyl tetrahydrofuran was evaluated from the exciplex emission of Cz–TP ranging from 77 to 292 K, indicating that the Cz–TP molecule is an excellent polarity probe not only in a liquid phase but also in a solid phase over a wide temperature range.

Light emitting oligomers containing 2,3,4,5-tetraphenylthiophenyl moiety and silyl linkage

Light emitting oligomers of high photoluminescence (PL) quantum efficiency were prepared and emphasized in this study. Thereby, four light emitting oligomers containing 2,3,4,5-tetraphenylthiophene (TP) moiety were prepared by Heck coupling between 2,5-bis(4-bromophenyl)-3,4-diphenylthiophene and four diene monomers. Certain diene monomers containing silyl unit were especially used in an attempt to introduce π–σ conjugation into the oligomeric products. Four products exhibited similar UV-Vis absorption and emission properties, with their absorption maxima ( λ max) ranged from 338 to 391 nm and emission maxima (PL max) from 487 to 505 nm. Quantum efficiency for the photoluminescent process was enhanced due to the inherently alternative phenylene–thiophene ring structure in the TP moiety and the silyl units introduced. Quantum efficiency was particularly increased from 28% to a value of 61–74%, if products were prepared from silyl-containing dienes instead of simple aliphatic diene monomer. With the incorporation of bulky TP moiety, four products were basically amorphous in nature and exhibited thermal stability at elevated temperatures.