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We herein report a Ni-catalyzed three-component cross-electrophile coupling of 1,3-dienes with aldehydes and aryl bromides using manganese metal as the reducing agent. This efficient protocol accomplishes dicarbofunctionalization of 1,3-dienes to synthesize diverse structural 1,4-disubstituted homoallylic alcohols by forming two new C-C bonds in one time. Mechanistic study suggests that an allyl-nickel(I) species is involved in the catalytic cycle.

π-Conjugated liquid-crystalline dimers consisting of two triphenylene mesogens connected through a rigid molecular bridge have been synthesized. Mesophases, gels and optical properties have been investigated as a function of the bridge nature.

Two series of regio-isomeric mesomorphous, luminescent and conductive compounds, based on a ditriphenylenothiophene core (α/β-DTPT), were successfully synthesized by the Suzuki–Miyaura cross-coupling/Scholl cyclo-dehydrogenation reactions tandem.

Two series of triphenylene-based dimers both having a central fluoromethylene spacer of four or six carbon atoms and ester or amide linkages were synthesised and their phase behaviour investigated. All the synthesised dimers are room-temperature discotic liquid crystals and exhibit hexagonal columnar mesophases that supercool into a stable anisotropic columnar glass. The length of the fluoromethylene spacer has a minor effect on the phase transition temperatures of these dimers. However, dimers 1a and 2a with a (CF2)4 spacer exhibit approximately 40°C higher clearing points and wider mesomorphic phase ranges compared with their hydrocarbon analogs 1c and 2c with a (CH2)4 spacer respectively. Compared to the corresponding ester-linked dimers 1a-c, three amide-linked dimers 2a-c exhibit 20°C higher clearing points upon cooling. The observation indicates not only that the introduction of the fluoromethylene spacer stabilised the mesophase in these discotic dimers, but also that the two interactions have synergistic effects on columnar packing in this system. Moreover, only amide-linked dimers exhibit good gelation property in a mixture of toluene and petrol ether, with a lower critical gelation concentration of 1.5 wt/vol%, thus indicating that gel formation occurred under the collaboration of hydrogen bonding and intrinsic π interactions in these dimers.

1,4-disubstituted 1H-1,2,3-triazoles L was successfully synthesised using a catalyst-free click reaction between an internal alkyne and an azide compound. Refluxing click product L and palladium ch...

Hydrogels as flexible sensor have attracted significant attention due to its conductivity, stretchability and flexibility. However, it is still a great challenge to prepare hydrogels that simultaneously possess high strength, anti-fatigue, self-adhesion, and anti-freezing. Herein, a multifunctional dual-network hydrogel was prepared by in situ polymerization of acrylic monomer in chitosan chains, and coordinated with aluminum chloride and glycerol. Based on chain entanglement, hydrogen bonding and coordination interactions, this dual-network hydrogel exhibited excellent mechanical properties, good fatigue resistance, and excellent adhesion performance. It can be used as a strain sensor for its stable conductivity and high sensitivity, which could monitor both large human motions and subtle motions. Due to the presence of glycerol, the hydrogel showed outstanding freezing resistance and still kept flexible and conductive even at low temperatures (-20 °C). This hydrogel can be applied as a flexible wearable sensor for monitoring human motion in extreme low-temperature condition.

The site-selective functionalization of unactivated aliphatic amines is an attractive and challenging synthetic approach. We herein report a general strategy for the remote site-selective functionalization of unactivated C(sp3)-H bonds in amides by photogenerated amidyl radicals to form gem-difluoroalkenes with trifluoromethyl-substituted alkenes. The site selectivity is controlled by a 1,5-hydrogen atom transfer (HAT) process of the amide. This photocatalyzed transformation shows both chemo- and site-selectivity, facilitating the formation of a secondary, tertiary, or quaternary carbon center.

Mesomorphous butterfly-like shape molecules based on benzodithiophene, benzodithiophene-4,8-dione and cyclopentadithiophen-4-one core moieties were efficiently synthesized by the Suzuki-Miyaura coupling and Scholl oxidative cyclo-dehydrogenation reactions' tandem. Most of the butterfly molecules spontaneously self-organize into columnar hexagonal mesophase. The electron-deficient systems possess strong solvent-gelling ability but are not luminescent, whereas the electron-rich terms do not form gels but strongly emit light between 400 and 600 nm. The charge carrier mobility was also measured by time-of-flight transient photocurrent technique in the mesophases for some of the compounds. They display hole-transport performances with positive charge mobility in the 10 -3 cm -2 V -1 s -1 range, consistent with the high degree of ordering and stability of the columnar superstructures. One mesogen in particular with benzodithiophen-4,8-dione core shows outstanding ambipolar charge carrier transport with both high electron (μe = 6.6×10 -3 cm -2 V -1 s -1 ) and hole (μh = 4.5×10 -3 cm -2 V -1 s -1 ) mobility values.

International audience; A generic synthetic method based on the Suzuki-Scholl reactions was successfully exploited to yield new poly(hetero)aromatic hydrocarbons containing carbazole, fluorene or fluorenone moieties. These butterfly-like mesogens exhibit columnar mesophases, form fibrous gels in various solvents, emit blue to orange light in films and solutions and show outstanding photocurrent behavior with charge carrier mobility in the ∼0.03 cm 2 V −1 s −1 range.

Being a link between a uniaxial nematic and a chiral nematic, the twist bend nematic (NTB) has been an intriguing topic for research over the last decade as a key to understanding chirality generation. Accurate description and understanding of resonance effects in helical structures provide crucial knowledge on the phase behavior beyond positional ordering. We examined the manifestation of resonance effects in NTBvia tender resonant X-ray scattering (TReXS) at the sulfur K-edge. For the first time we demonstrate quantitatively that the energy dependence of the scattering peak in the NTB phase follows the energy dependence of the complex refractive indices measured by X-ray absorption. Taking advantage of molecular energy calculation, we decipher the distinct helical pitch variation trend for symmetric/asymmetric dimers from the perspective of hybridization and reveal the strong effect of substituting oxygen for sulfur atoms on the helical pitch and the thermal helix extension.

We report on the straightforward synthesis of a new series of ionic discotic liquid crystals based on positively charged azatriphenylene. In our design, the quaternized azatriphenylene core is surrounded by four to six flexible aliphatic chains and various types of anions, including small inorganic anions (i.e. Br−, I−, NO3−, BF4−, PF6−), and organic ones such as triflate, bis(trifluoromethylsulfonyl)imide, tosylate, saccharinate, D and L camphorsulfate, alkylsulfonates, and alkylsulfates. The mesophases and thermal behaviour of the salts were characterized by polarizing optical microscopy, differential scanning calorimetry, thermal gravimetry and small-angle X-ray scattering. A classical hexagonal columnar mesophase, i.e. p6mm-Colhex, was observed for most salts. Two exotic new phases were however identified for four compounds, namely a mesophase with a hexagonal lattice of p3m1 symmetry (Hex), and another mesophase with a rectangular lattice of pseudo-hexagonal geometry (i.e. a/b = √3) of p2mg symmetry (Recphex). The former results from the bulkiness of the triflimide anion and the arrangement of columns into a honeycomb lattice, whereas the latter is induced by the clustering of three columns, disposed according to a low-symmetry rectangular lattice. Their temperature ranges and stabilities strongly depend as expected on the anion type and the number (and length) of the alkyl side-chains (O- and N-alkyl, respectively), highlighting the delicate balance and interplay between van der Waals, electrostatic and π–π core interactions. The UV/Vis absorption and fluorescent emission spectra were measured, and a strong yellow light photoluminescence was observed depending on the anion type, whereas anion-selective luminescence was observed in thin films. The neutral azatriphenylene precursor, 6,7,10,11-tetrakis(hexyloxy)dibenzo[f,h]isoquinoline, is also an interesting luminophore, showing an absolute emission quantum yield of 75%, while the corresponding salts exhibit anion-selective emission quantum yields as high as 20%.

Staphylococcus aureus is a common pathogen in chronic rhinosinusitis (CRS) patients, the pathogenesis of which involves the ability to form biofilms and produce various virulence factors. Tobacco smoke, another risk factor of CRS, facilitates S. aureus biofilm formation; however, the mechanisms involved are unclear. Here, we studied the effect of nicotine on S. aureus biofilm formation and the expression of virulence-related genes. S. aureus strains isolated from CRS patients and a USA300 strain were treated with nicotine or were untreated (control). Nicotine-treated S. aureus strains showed dose-dependent increases in biofilm formation, lower virulence, enhanced initial attachment, increased extracellular DNA release, and a higher autolysis rate, involving dysregulation of the accessory gene regulator (Agr) quorum-sensing system. Consequently, the expression of autolysis-related genes lytN and atlA, and the percentage of dead cells in biofilms was increased. However, the expression of virulence-related genes, including hla, hlb, pvl, nuc, ssp, spa, sigB, coa, and crtN was downregulated and there was reduced bacterial invasion of A549 human alveolar epithelial cells. The results of this study indicate that nicotine treatment enhances S. aureus biofilm formation by promoting initial attachment and extracellular DNA release but inhibits the virulence of this bacterium.

Although transition-metal-catalyzed C-C bond activation has been investigated extensively, C-C bond cleavage manipulated by hydrogen transfer has been unexplored. In this work, we disclose a skeleton reorganization of alkene-tethered benzocyclobutenols through Rh-catalyzed C-C bond cleavage coupled with intra- and intermolecular hydrogen transfer. The reaction pathway was well-tuned by the catalytic systems. As a result, divergent benzofurans bearing 4-β-hydroxy or 4-β-keto moieties were synthesized under pH- and redox-neutral conditions.

A modular synthesis of 2,8-dioxabicyclo[3.2.1]octane (2,8-DOBCO) ketals is realized by sequential catalysis. The key intermediates, e-hydroxyl-β,γ-unsaturated ketones, are readily available by Ni-catalyzed three-component coupling of 1,3-dienes, aldehydes, and acylzirconocene reagents. These polyfunctionalized ketones can undergo a V-catalyzed cascade of epoxidation and ring rearrangement to provide access to 6-hydroxyl-2,8-DOBCOs. Mechanistic studies indicate that the V(V) species, generated under epoxidation conditions, promotes the ring rearrangement in a stereospecific manner. Meanwhile, the e-hydroxyl-β,γ-unsaturated ketones are transformed into 6-amino-2,8-DOBCOs by a Cu-catalyzed cascade of aziridination and ring rearrangement. In the end, the one-pot approach toward 6-hydroxyl- or 6-amino-2,8-DOBCOs from 1,3-diene, aldehydes, and acylzirconocene reagents is more favorable.

Board-like liquid-crystalline semiconductors based on the dithieno[3,2-b;2',3'-d]thiophene (DTT) substructure were synthesized and their thermal, self-assembly, optical, and semiconducting properties investigated. These sanidic compounds, bearing eight peripheral chains, are mesomorphic and spontaneously self-assemble into columnar hexagonal mesophases (Colhex ) over broad temperature ranges, as confirmed by polarized optical microscopy, differential scanning calorimetry, and small-angle X-ray scattering. Strong blue photoluminescence with absolute quantum yields up to 33 % were measured. These compounds also form blue-light emitting gels in various organic solvents. The fibrillar-like morphology of these gels, reminiscent of the columnar structure, and stabilized by efficient intermolecular interactions, was characterized by scanning electron microscopy. The charge carrier mobility of these π-extended mesogens was measured by time-of-flight transient photocurrent technique in the Colhex mesophase, and showed good hole-transport performance with charge carrier mobility of 10-3 cm2 V-1 s-1 .

In this study, we introduced 2-ureido-4[1H]-pyrimidone (UPy) group into polyurethane, which showed both heat and pH-sensitive shape memory effect. UPy dimers were used as switch to control the shape change. In pH-induced shape memory procedure, the dimer of UPy are formed to hold the temporary shape in alkaline (pH 10), and which are dissociated to cause shape recovery in acidic solution (pH 1). The shape fixation ratio and recovery ratio both can reach 80%. The polyurethane with UPy groups also showed good seal-healing property. After heating above 40°C for 3h, the stress of healing specimen can reach 86% that of original ones. By introducing UPy into polyurethane backbone, heat and pH-sensitive shape memory and heat induced healing can be achieved.

The site-selective functionalization of unactivated aliphatic amines is an attractive and challenging synthetic approach. We herein report a general strategy for the remote site-selective functionalization of unactivated C(sp

The technique of maxillectomy has been revised since it was first described in the 1820s. During the past decade, the endoscopic approach has been widely practiced for resecting maxilla. Compared with the traditional approaches, the combined endoscopic and transoral approach has many advantages such as avoiding facial incisions and postoperative scars and better visualization of the surgical margin. However, this technique is complicated to master and possess several challenges. Here, we demonstrate this approach step-by-step to show how to perform a total maxillectomy. We also reported nine cases with malignant tumors originating from the maxilla, and for all of them total maxillectomy was performed with combined endoscopic and transoral approach. Our data showed that the combination of the endoscopic and transoral approach could be used to resect the total maxilla successfully, though the tumor extended to the infratemporal and pterygopalatine fossa should be treated very carefully to avoid its spread in the local area. Furthermore, besides denture, other reconstruction methods should be attempted to improve the postoperative quality of life after the total maxillectomy.

Four truxeneones 6a-d in which three long alkoxy chains and three methoxy groups were C3-symmetrically attached to the truxenone core have been synthesised and studied with the aim to study the effect of bulky methoxy substituents on their mesomorphism and self-assembly properties. These four compounds show enantiotropic mesophase and each has a Colh phase over a 135°C temperature range. A comparison of the side chains showed that 6a-d with mixed alkoxy chains display more complex thermotropic behaviour than reported truxenones possessing six identical long alkoxy chains. Although the methoxy groups have almost no effect on their self-assembly in solution due to the staggered face-to-face arrangement of truxenone moieties, it is confirmed that replacement of three long alkoxy chains by methoxy groups may affect the packing of molecules in the crystalline state more than that within the mesophase. The presence of methoxy groups results in lowering of both the clearing point and the temperature range of the Colh phases by maintaining high melting point. Moreover, 6a self-assembles on a solid/liquid interface into a well-ordered two-dimensional architecture which was explored using high-resolution STM that closely resembles to the proposed bulk mesomorphic three-dimensional columnar phase deduced from XRD.

Three star-shaped oligomers with an electron-deficient truxenone (TrO) as the central core and three electron-rich triphenylenes (TP) as the peripheral arms were prepared, in which the triphenylenes groups are, respectively, connected to the central truxenone core at 2, 7 and 12 positions through a highly flexible O(CH2)nO (n = 6,8,10) polymethylene chain. All these triphenylene-armed oligomers TrO[O(CH2)nOTP]3 (n = 6,8,10) exhibit liquid crystalline over broad mesophase ranges including room temperature. Oligomer TrO[O(CH2)6OTP]3 exhibit a rectangular columnar mesophase, while others with the linkage longer show a hexagonal columnar mesophase. This modulation of phase behaviours was demonstrated to be generated by steric perturbations introduced between the three decyloxy substituents in central truxenone core and the linkages with different lengths, which cause the disturbance of the intracolumnar structure and influence the degree of ordering in columnar phases. No new electronic absorption except for the usual bands of the individual truxenone or triphenylene part was observed in dichloromethane solution of TrO[O(CH2)6OTP]3. However, two new emission peaks emerged and the intensity and position of the emission peaks were found to exhibit pronounced changes upon concentration variation, which can be attributed to the formation of intermolecular excimers.

International audience; Liquid-crystalline D-A dyads and A-D-A triads, based on the chemical association of electron-donor (D) triphenylene discogens and electron-acceptor (A) perylene/benzoperylene diimides, have been synthesized by the Pd-catalyzed Sonogashira coupling/DBU-promoted cyclization reactions tandem. These molecular heterojunctions spontaneously self-organize into columnar hexagonal (Colhex) or/and rectangular (Colrec) mesophases, over broad temperature ranges including room temperature, with the antagonist moieties segregated into alternated homo-molecular (homolithic) stacks within mixed columns. Their intramolecular electron and energy transfers have been studied by UV/Vis absorption and fluorescence emission spectroscopies. Due to photo-induced electron transfer between donor and acceptor units, fluorescence quenching is systematically observed for all the dyads and triads. This study further reveals that perylenediimide is a stronger electron acceptor than the larger benzoperylenediimide building block. Density function theory calculations of their molecular structures and HOMO-LUMO energy levels and gaps support the experimental results and demonstrate that these donor-acceptor systems have potential applications in various optoelectronic devices.

Water as a common, easily obtained, and environmentally friendly stimulus has been explored in stimuli-responsive materials. In this paper, a series of composites, named as PVA(n)-CMC(m)-GA, were prepared by filling the carboxymethyl cellulose sodium (CMC) into chemical cross-linked poly(vinyl alcohol) (PVA). These composites demonstrated both water induced shape memory and self-healing effect. CMC with water sensitivity help the composite absorbing water to decrease the Tg of composite to cause shape recovery. And CMC with water solubility is also a good healing agent, which can freely move across the cutting cross-section in wet condition and form hydrogen bonds with PVA chains in dry condition to achieve healing. Water can affect the hydrogen bonding interactions between CMC and PVA, and which play a key role in the water-stimuli responsive properties. This study provides a relatively simple and low cost way to obtain water-induced multifunction materials.

BACKGROUND Postoperative care is an important factor affecting the outcome of endoscopic sinus surgery (ESS) in patients with chronic rhinosinusitis (CRS). The aim of this study was to test the effect of mometasone furoate (MF)-soaked biodegradable nasal dressings (BNDs) on endoscopic appearance in CRS patients with nasal polyps (CRSwNP) after ESS. METHODS This study was a prospective, randomized, double-blinded, placebo-controlled study. A total of 64 CRSwNP patients with bilateral ESS were enrolled and randomly given 4 mL or 8 mL of MF-soaked BNDs (NasoPore) in 1 nasal cavity and the same amount of normal saline-soaked BNDs in the contralateral side. The BNDs were removed on the 7th or 14th postoperative day. Perioperative sinus endoscopy (POSE) and Lund-Kennedy scores were collected, on the 7th or 14th postoperative days and at 1, 2, and 3 postoperative months. RESULTS The POSE and Lund-Kennedy scores showed that in the 4-mL, 1-week group, no significant differences between the sides treated with MF-soaked BNDs and the normal saline-soaked control were observed at any postoperative visits. In the 4-mL, 2-week group, significant differences were found at the 2-week and 1-month postoperative visits but not at the 2-month and 3-month visits. In the 8-mL, 1-week group, significant differences were found at the 1-week, 1-month, and 2-month postoperative visits but not at the 3-month visit. In the 8-mL, 2-week group, significant differences were found at all postoperative visits. CONCLUSION This study reveals that MF-impregnated BNDs improve the endoscopic appearance in the healing process of CRSwNP after ESS.

International audience; Discotic polyaromatic liquid crystals exhibiting 2D columnar mesophases are actively investigated for their potential utilization as one-dimensional organic semiconductors, due essentially to their long-range order self-organization and high charge carrier transport ability. The much less reported nematic-containing discotic materials have however been recently found to be of industrial importance too. In this context, highly conjugated fluorene-bridged triphenylene triads have been designed with the aim of inducing room temperature nematic phases. In our approach, the length of the alkyl chains bore by the central fluorene unit was changed in order to constrain the space-filling, to modulate the intermolecular π–π interactions, and to control the tendency of the molecular triads to stack into columns, and the subsequent aggregation of the columns in specific ways. This strategy was successful, and in addition to the naturally expected two-dimensional columnar mesophases, most triads exhibit the more elusive columnar nematic phase, as only the orientational-type long-range order is preserved. Photoluminescence, measured in both solution and thin films, revealed strong blue emission, characteristic of the fluorene moiety, with impressively high quantum efficiency. Charge carrier mobility measurements revealed novel p-type molecular semiconductors with hole transport mobility in the range of 0.2–2 × 10–3 cm2 V–1 s–1 in the mesophases (Colrec, Colhex, and NCol) and up to 5 × 10–4 cm2 V–1 s–1 in the isotropic phase. Reasons for the occurrence of these mesophases and their supramolecular structures are discussed along with the effects on the semiconducting properties.

An efficient protocol to synthesize unsymmetrical triphenylenes from electron-rich biphenyls and diaryliodonium salts via Cu catalysis was developed. A variety of unsymmetrical triphenylenes with diversified functional groups were synthesized according to this method. This transformation went through multiple direct C-H arylations from easily produced starting materials with high step-economy. The gram-scale synthesis of triphenylenes and their facile transformation into diverse functional organic molecules were illustrated.

Herein, four new H-shaped triphenylene discotic liquid crystal tetramers have been designed and synthesized using a copper-free [3+2] cycloaddition reaction between the triphenylene dimer and diazide compounds. To probe the molecular self-assembly and mesophase properties, the length and rigid spacers in diazide have been tailored. The tetramers 7 with a soft spacer display a room-temperature enantiotropic DLC mesophase, and X-ray diffraction confirms that they exhibit an unusual mesophase of a lamellar–hexagonal columnar phase (Colhl). The results of the photophysical tests show that all the new H-shaped DLC tetramers display relatively high intensity photoluminescence properties.

Based on the need for whole biomass hydrogels in biomedical applications, a dual-crosslinked hydrogel based on natural product sodium alginate (SA) were prepared. Dual-crosslinked was formed by SA crosslinking with glutaraldehyde (GA) and calcium ion (Ca2+), and the introduction of carboxymethyl cellulose (CMC) into crosslinked network to obtain excellent water-induced shape memory property. The chemical and physical crosslinking net points, formed by GA and Ca2+, as the stationary phase to hold the original shape; While hydrogen bonding interactions between CMC and SA as the switcher to fix the temporary shape in air and driving the recovery in water. The shape fixing and recovery ratio can reach 90%. The dual crosslinking effect and introduction of CMC, also strengthen the mechanical properties of hydrogels and change the size of pores in hydrogels. Cell culture experiment showed that these hydrogels are good at biocompatibility and can control the cell differentiation by adjusting the size of pores in hydrogel networks. For its excellent performance, these hydrogels can be potentially applied as biological device materials in the field such as soft tissue engineering, controlled drug release and bioactuators.

The ‘one-pot’ reaction of 2-hydroxy-3,5-di-tert-butylsalicylaldehyde with in situ generated ‘amino calixarene’ (from {Mo[(2-NC6H4)2CH2CH2]Cl2(DME)}, KOtBu and p-tert-butylcalix[4]areneH4 LH4) afforded, after work-up, the heterobimetallic salt K(NCMe)2[Mo(NCMe)(OEt)(2-C6H4CH2CH2C6H4NH2-2)L] (1∙2MeCN). By constrast, use of the ‘amino calixarene’ [Mo(NCMe)(2-C6H4CH2CH2C6H4NH2-2)L] afforded the potassium/ethoxide-free complex [Mo(NCMe)(2-C6H4CH2CH2C6H4N-2-CHC6H2-2′-(OH)-3′,5′-tBu)L] (2∙2MeCN). Reaction of the ‘amino calixarene’ (two equivalents) with the dialdehyde [1,3-(CHO)2-5-MeC6H3OH-2] led, following work-up, to the isolation of the cation-anion pair [C46H42N4O2]2+[Mo6O19]2−·C2H3N (3∙MeCN). The molecular structures of 1·2MeCN, 2·2MeCN and 3·MeCN are reported, for which it was necessary to use synchrotron radiation for data collection. Complex 1 contains an eliptical calixarene conformation as a result of π-interactions between the K+ and the arene groups and a distorted O5N octahedral geometry at...

A new variety of non-symmetrical triphenylene-based discogens has been synthesized by intramolecular Scholl cyclodehydrogenation reaction of kinked terphenylenes using the FeCl 3 /MeNO 2 couple as an efficient oxidant. The “Janus-like” tetrakis(alkoxy)triphenylene discogens containing electron-withdrawing groups, such as cyano-, chloro- and fluoro-substituents, or electron-donating moieties, such as carbazole, thiophene and naphthalene at the opposite of the alkylated side were prepared in good to high yields. Polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) investigations revealed that six of the 14 discogens synthesized exhibit a hexagonal columnar mesophase. These chromophores emit bright blue light from 350 nm to 500 nm in solution depending on the extension of their π-conjugation. In addition, all six columnar liquid crystals show non-dispersive time-of-flight photocurrent transportation, with charge carrier drift mobility in the range of 10 −3 to 10 −4 cm 2 V −1 s −1 , higher or in the same range as their symmetrical hexa(alkoxy)triphenylene parent compounds.

Reaction of R1R2CHN=CH(3,5-tBu2C6H2-OH-2) (R1 = R2 = Me L1H; R1 = Me, R2 = Ph L2H; R1 = R2 = Ph L3H) with slightly greater than one equivalent of R33Al (R3 = Me, Et) afforded the complexes [(L1–3)AlR32] (L1, R3 = Me 1, R3 = Et 2; L2, R3 = Me 3, R3 = Et 4; L3 R3 = Me 5, R3 = Et 6); complex 1 has been previously reported. Use of the N,O-ligand derived from 2,2′-diphenylglycine afforded either 5 or the byproduct [Ph2NCH2(3,5-tBu2C6H2-O-2)AlMe2] (7). The known Schiff base complex [2-Ph2PC6H4CH2(3,5-tBu2C6H2-O-2)AlMe2] (8) and the product of the reaction of 2-diphenylphosphinoaniline 1-NH2,2-PPh2C6H4 with Me3Al, namely {Ph2PC6H4N[(Me2Al)2µ-Me](µ-Me2Al)} (9), were also isolated. For structural and catalytic comparisons, complexes resulting from the interaction of Me3Al with diphenylamine (or benzhydrylamine), namely {Ph2N[(Me2Al)2µ-Me]} (10) and [Ph2CHNH(µ-Me2Al)]2·MeCN (11), were prepared. The molecular structures of the Schiff proligands derived from Ph2CHNH2 and 2,2′-Ph2C(CO2H)(NH2), together with those of complexes 5, 7 and 9–11·MeCN were determined; 5 contains a chelating imino/phenoxide ligand, whereas 7 contains the imino function outside of the metallocyclic ring. Complex 9 contains three nitrogen-bound Al centres, two of which are linked by a methyl bridge, whilst the third bridges the N and P centres. In 10, the structure resembles 9 with a bridging methyl group, whereas the introduction of the extra carbon in 11 results in the formation of a dimer. All complexes have been screened for their ability to promote the ring-opening polymerization (ROP) e-caprolactone, δ-valerolactone or rac-lactide, in the presence of benzyl alcohol, with or without solvent present. Reasonable conversions were achievable at room temperature for e-caprolactone when using complexes 7, 9 and 12, whilst at higher temperatures (80–110 °C), all complexes produced good (> 65 %) to quantitative conversions over periods as short as 3 min, albeit with poor control. In the absence of solvent, conversions were nearly quantitative at 80 °C in 5 min with better agreement between observed and calculated molecular weight (Mn). For rac-lactide, conversions were typically in the range 71–86 % at 110 °C in 12 h, with poor control affording atactic polylactide (PLA), whilst for δ-valerolactone more forcing conditions (12–24 h at 110 °C) were required for high conversion. Co-polymerization of e-caprolactone with rac-lactide afforded co-polymers with appreciable lactide content (35–62.5 %); the reverse addition was ineffective, affording only (polycaprolactone) PCL.

A novel small-sized discotic core was constructed by fusing an imide unit with well-known triphenylene core. All target compounds 6a-k self assemble into a liquid crystalline phases having high clearing temperatures and broad phase ranges over 200 °C, and exhibit green luminescence both in solution and solid states. On cooling from the isotropic phase, compounds 6d-e and 6i-j containing the branched N-alkyl chain show only one peak for the isotropic to mesophase transition which is stable down to −50 °C. Comparison of 6a's mesomorphic behaviors and photophysical properties to a known hexahexyloxytriphenylene (1a) and the parent compound (4a) demonstrates the importance of peripherally attached functional groups in stabilizing columnar mesophases and inducing long-wavelength emission. Both the experimental results and computational calculations show that suitable peripheral functionalization of the discotic liquid crystal molecules not only results in significant differences in mesogenic behavior of the molecules, but also renders the molecules with the interesting optoelectronic properties, including large Stokes shifts and low-lying LUMO energy levels.

Fused-thiophene discotic liquid crystals were designed and easily synthesized by Suzuki coupling and FeCl3 oxidized tandem cyclodehydrogenation reactions, including homo- and cross-coupling reactions. The resulting hexagonal and rectangular columnar mesomorphic supramolecular structures formed were characterized by polarizing optical microscopy, differential scanning calorimetry, and small-angle X-ray scattering. The charge carrier transport properties in the mesophases of two of the synthesized fused-thiophene discogens were measured by transient photocurrent time-of-flight (TOF) technique, revealing fast hole transport values in the range of 10-3 to 10-2 cm2 V-1 s-1 , thus demonstrating potential applications in electronic devices. The luminescent sanidic mesogens, with different extended π-conjugated systems, also emit blue, green, or red light, with absolute photoluminescent quantum yields as high as 18 %.

Four new mesomorphic triphenylene-fused nitrogen-containing heterocyclic systems, including three benzimidazole and one perimidine derivatives with extended triphenylene core of different sizes are synthesised from the condensation reaction between aromatic diamines and our developed triphenylene dicarboxylic anhydrides. These discotic mesogens self-assemble into supramolecular columnar hexagonal mesophases with high clearing transition temperatures, demonstrating a strong tendency for π-stacking aggregation in the LC state owing to their good planar molecular structures. Four triphenylene-fused mesogens exhibit strong absorption bands in the range of 262 nm to 450 nm and corresponding emission bands between 468 nm and 615 nm, respectively. Both the experimental results and computational calculations show that the mesomorphic and electronic properties of four mesogens are strongly affected by the expansion of triphenylene core and the electronic nature of the nitrogenated benzimidazole or perimidine ring. Besides, these mesogens also possess higher HOMO energies and narrower HOMO-LUMO gaps than parent anhydride. Furthermore, the solution of TDPI or TDP in THF at a concentration as low as 0.45 wt % exhibited organogel phases due to strong intermolecular π-π interactions between the large aromatic cores. All these properties qualify this new type of discotic liquid crystals as potential applications as organic semiconductor materials and sensors.

Pd-catalyzed Suzuki cross-coupling reactions between arylboronic acids and bromoarenes have been applied widely in the synthesis of liquid-crystalline materials. However, aryl triflate derivatives have been less used despite their high chemical tolerance, reactivity, and chemical accessibility. In this report, three series of discogens have been synthesized in good yields from appropriate triphenylene triflate precursors by Suzuki coupling reactions with various commercial arylboronic acids (e.g., aryl = phenylene, thiophene, naphthalene, triarylamine, carbazole, and fluorene). The synthesized discogens display broad mesophase ranges and high thermal stabilities. Moreover, those bearing triarylamine, carbazole, and fluorene side groups are also blue-light emitters. The availability of the triflate precursors coupled with their highly efficient cross-coupling with commercial arylboronic acids make this strategy extremely versatile and attractive for the design of new functional materials.

A new and straightforward method has been developed to synthesize polysubstituted benzo[g]chrysene (BgCh) according to controlling the exact stoichiometry of FeCl3 from diphenylacetypene and phenylacetaldehyde derivatives under mild conditions. The BgCh derivatives can also be functionalized by halogenation with Cl, Br and I on the newly built aromatic ring. All the compounds have been fully characterized as well as their photophysical properties, and some of them demonstrated extraordinary liquid crystallinity. The compounds 4e, 4h, 5e and 5h exhibited hexagonal columnar mesophases (Colh). In particular, 5h showed a rectangular columnar plastic phase (Colrp) under 35 °C on cooling. The fluorescence spectra of BgCh revealed a strong emission peak at 405 nm and a shoulder peak near 424 nm in DCM in the range of blue light.

A type of polyurethane with a thermo-induced triple shape memory effect and a pH-sensitive dual shape memory effect has been developed. Firstly, a series of polyurethanes were successfully synthesized through solution polymerisation of polyethylene glycol (PEG, Mn = 4000 kg mol−1), dimethylolpropionic acid (DMPA) and 4,4′-diphenylmethane diisocyanate (MDI). These polymers were named as PEG-i-MDI-DMPA (i = 20%, 30%, 40%), and i represents the weight content of PEG in the polymers. The results of shape memory testing showed that the PEG-30%-MDI-DMPA displays both the triple-shape memory effect and the pH sensitive dual-shape memory effect. In PEG-30%-MDI-DMPA, the glass transition of PEG chains and the association and disassociation of carboxylic dimers act as two switches to control the triple-shape memory effect, while the carboxylic dimer is affected by pH values to associate in acidic solutions (at pH 2) and dissociate in alkaline solutions (at pH 9) to induce the pH-sensitive shape memory. The carboxylic dimers play an important role in the construction of shape memory properties in this polyurethane.

We report herein the design and synthesis of some novel liquid crystalline semiconductors constructed from a biologically and pharmacologically active building block molecule, namely 6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene, presenting efficient luminescence and medium charge mobility rate. A first series of mesogenic 2-phenylbenzothiophene derivatives (nPBT) was simply and rapidly obtained in good yields by successive demethylation/alkylation reactions of the available methoxy precursor. The further stepwise oxidations moreover resulted in two new sets of the corresponding sulfoxide (nPBTO) and sulfone (nPBTO2) derivatives, respectively, that were also mesomorphic. The liquid crystalline behaviour was comprehensively characterized by DSC, POM and SAXS: all compounds exhibit smectic-like behaviour in agreement with their calamitic shape. More specifically, mesogens nPBT showed a SmA phase, with in addition, a higher ordered smectic phase at lower temperature. As for the oxidized mesogens, they displayed a SmA phase only, and over particularly large temperature ranges for the nPBTO with longer chain lengths (n ≥ 8). The photo-physical properties have also been studied both in solution and thin films, and the molecules were found to display strong absorption in the UV/vis domain and intense luminescence in the range of 400–650 nm (yellowish green light) in high quantum yields (up to 62%). Both absorption and luminescence were also found to be affected by the oxidation of the benzothiophene moiety. Finally, the semi-conducting behaviour of three PBT compounds in the various mesophases was investigated by photocurrent TOF technique. Hole mobility rates of ca. 4 × 10−3 cm2 V−1 s−1 were measured in the lower temperature ordered mesophase for all of them, with the best performances (temperature range and mobility values) however obtained for the shortest homolog (n = 6). With such highly reasonable mesomorphic, light-emitting and semiconducting functional features, as well as being cheap and easy to synthesize and to process, these materials become very attractive and may be incorporated into various kinds of electronic devices (OFET and OLED).

Staphylococcus epidermidis is a common bacterial colonizer of human skin and mucous membranes, yet it has emerged as an important nosocomial pathogen largely due to its ability to form biofilms. Tobacco smoke has been demonstrated as a contributor to various infection diseases by improving the biofilm formation of multiple bacterial species; however, the association between tobacco smoke and S. epidermidis biofilm is still unclear. In this study, we tested the effect of nicotine, one of the most active components of tobacco, on S. epidermidis biofilm formation, and we studied the underlying mechanisms. Our results showed that nicotine promoted the biofilm formation of S. epidermidis 1457 strain (SE1457) and enhanced its initial attachment to a polyethylene surface as well as polysaccharide intercellular adhesin (PIA) production. In addition, an increased extracellular DNA release and a higher autolysis rate of SE1457 was detected after nicotine treatment, which was consistent with the increased ratio of dead cells in nicotine-treated SE1457 biofilm observed with confocal laser-scanning microscopy. Furthermore, the effect of nicotine on several autolysis-related and biofilm-related gene knockout mutants of SE1457 was tested. It showed that in ΔsaeRS, ΔlytSR, and ΔsceD, nicotine induced increase in biofilm formation was similar to that in SE1457; but in ΔarlRS, ΔatlE, and ΔicaC, the effect was obviously impaired. Consistently, the increase of the bacterial autolysis rate in ΔarlRS and ΔatlE induced by nicotine was not as significant as that in SE1457. Meanwhile, the growth inhibition of nicotine on SE1457 was observed, and it was much less on ΔarlRS and restored by the arlRS complementation. The arlRS transcription in SE1457 was inhibited by nicotine during cultivation as indicated by a promoter reporter assay using green fluoresent protein. Taken together, our study indicates that nicotine improves S. epidermidis biofilm formation by promoting its initial attachment and intercellular accumulation; the arlRS, atlE, and ica genes mediating bacterial autolysis and PIA production play an important role in this process.

Endoscopic septoplasty is a surgical procedure in otolaryngology that is commonly performed to treat nasal airway obstruction caused by nasal septal deviation. It has a long history with multiple variations. In this article, a modified endoscopic septoplasty procedure using the limited two-line resection (2LoRs) technique at the posterior and inferior junction of the cartilaginous and bony septum is presented based on embryologic and anatomic knowledge of the nasal septum and the biomechanics of cartilaginous behavior. With this procedure, the quadrangular cartilage can be preserved as much as possible, which is helpful in retaining the supporting framework and rigidness of the septum. 2LoRs has been proven effective and sound for the correction of nasal septal deviation with rare complications. This modified procedure can be applied to correct the deviated nasal septum in the absence of any external nasal deformity to improve nasal patency or to improve access to the middle meatus or to the axillary region of the middle turbinate. It may also be used to expand the indications of septoplasty to children and adolescents because of its minimally invasive approach.