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Genotyping of the epidermal growth factor receptor (EGFR) mutation status is of great importance in the screening of appropriate patients with advanced non-small cell lung carcinoma (NSCLC) to receive superior tyrosine kinase inhibitor (TKIs) therapy. Yet conventional assays are generally costly with a relatively long turnaround time for obtaining results, which can lead to a bottleneck for immediately starting TKI therapy in late-staged patients. In this study, we propose an on-site electrochemical platform for sensitive simultaneous genotyping of the two major EGFR mutations (19del and L858R) through plasma ctDNA based on tetrahedral DNA nanostructure decorated screen-printed electrodes (SPE). Linear-after-the-exponential (LATE)-PCR combined with the amplification refractory mutation system (ARMS) was adopted to produce abundant biotin-labeled single-stranded DNA with high amplification efficiency and specificity. Disposable SPE decorated with self-assembled tetrahedral nanostructured DNA probes that showed ordered orientation and good target accessibility enabled the highly efficient hybridization of the specific amplicons through a sandwich-type and quantitatively translated the interfacial hybridization event into electrochemical signals via enzymatic amplification. Taking advantage of the ARMS-based LATE-PCR and the tetrahedral nanostructure-decorated SPE platform, we achieved the accurate detection of around 30 pg DNA of 19del or L858R, or as low as 0.1% of them in the presence of wild-type DNA. Moreover, the EGFR mutation profiles of 13 NSCLC patients we enlisted were accurately genotyped by our electrochemical platform, the results of which were in good agreement with those of commercial genetic detection methods. [ABSTRACT FROM AUTHOR]

The simultaneous incorporation of N-oxide and nitramine is a significant approach for improving the oxygen balance, density and detonation performance of energetic materials. Herein, an intramolecular hydrogen-bond block was stabilized in novel s-triazine energetic materials. Meanwhile, as the first instance of successful N-oxidation in the s-triazine backbone, the as-synthesized energetic compounds exhibited multipurpose applications. Compound 4 showed detonation performance comparable to that of FOX-12 but more insensitive and thermally stable (IS ＞ 80 J, Td: 275 °C). Compound 5 presented excellent physical and detonation properties similar to RDX, including high densities (up to 1.86 g cm−3), high energetic performances (calculated detonation velocity: 8762 m s−1) and low mechanical sensitivities (IS = 40 J) superior to those of RDX, demonstrating promise as a novel insensitive highly energetic material. [ABSTRACT FROM AUTHOR]

Dicarbohydrazide bis[3-(5-nitroimino-1,2,4-triazole)] (DCBNT) was firstly synthesized by ion exchange and salt formation reaction. A combination of single-crystal X-ray diffraction (SXRD), FTIR, 1H NMR, 13C NMR, and elemental analysis was utilized to analyze the structure and composition of DCBNT. DCBNT exhibits a high detonation velocity of 9234.87 m s−1 and a detonation pressure of 31.73 GPa as calculated by EXPLO5 v6.02 program. In addition, the sensitivities (impact sensitivity ＞40 J, H50 = 90 cm, and friction sensitivity = 216 N) and thermal stability (＞230 °C) of DCBNT were investigated. Moreover, we measured the solubility of DCBNT in 12 common solvents by a polythermal method system which demonstrates its poor solubility in common organic solvents and water. These excellent physicochemical properties make DCBNT an environmentally friendly, low-sensitivity and high-energy explosive. [ABSTRACT FROM AUTHOR]

New D–A–D type difluoroboron β-diketonate complexes with terminal triphenylamines ABA, ABVA and AVBVA were synthesized. It was found that stable organogels could be gained from ABVA and AVBVA without traditional gelation groups in mixed solvents containing 1,4-dioxane, and balanced π–π interactions were the driving forces for the gel formation. Interestingly, the organogels based on ABVA and AVBVA exhibited emission close to the NIR (near infrared) region. To the best of our knowledge, such narrow band gap low molecular-weight π-gelators have not been reported. In particular, xerogel-based films generated from ABVA and AVBVA could be used as sensors to detect gaseous aliphatic primary amines with high performance. For example, after exposing to saturated n-butylamine and n-propylamine vapors for 30 s, the emission of the films was quenched completely and new strong emission at ca. 560 nm appeared on account of the decomposition of the difluoroboron β-diketonate complexes. [ABSTRACT FROM AUTHOR]

A new β-iminoenolate boron complex with a terminal triphenylamine (TP) was synthesized, and it could emit strong fluorescence in solutions and in solid states. Two types of crystals were obtained via evaporation of the solutions of TP in different solvents. A yellow ribbon-like crystal (Y-crystal) giving yellowish green emission centered at 518 nm was obtained from tetrahydrofuran (THF) solution, and a green needle-like crystal (G-crystal) emitting green light with maximum emission at 495 nm was yielded from dichloromethane (DCM)/petroleum ether solution. It was found that the molecules adopted a stacking mode of J-aggregation in the Y-crystal, and the π–π interaction in the G-crystal was weaker than that in the Y-crystal. Besides the polymorphism feature, TP exhibited mechanofluorochromic (MFC) properties. Upon being ground, the Y-crystal and G-crystal could transform into similar ground powders with yellow emission centered at 533 nm. Interestingly, when the ground powder formed from the Y-crystal or G-crystal was fumed with DCM or heated, the XRD pattern and the fluorescence emission spectrum of the fumed sample would be recovered to those of each of their own initial crystal states. Such memory ability of the molecular packing mode during reversible MFC processes might be useful for our well understanding the MFC mechanism. [ABSTRACT FROM AUTHOR]

We have synthesized three new salicylaldimine difluoroboron complexes with tert-butyl groups 1B–3B, which are highly emissive in solutions and in solid states. It was found that salicylaldehydehydrazone difluoroboron complex 1B could form organogels in n-hexane and the mixture of petroleum ether/CH2Cl2, and 1D nanoribbons with intense blue emission could be fabricated via the gelation of the nontraditional organogelator 1B directed by balanced π–π interaction. However, the other two salicylaldimine difluoroboron complexes 2B and 3B with a spacer of the benzene ring could not form a gel due to the strong π–π interaction, but exhibited piezofluorochromic behaviors. The as-prepared crystals of 2B and 3B giving blue-green fluorescence could be transformed into the powders emitting yellow light upon grinding, and the emission could recover when the ground powders were heated. It suggested that the reversible piezofluorochromism originated from the transformation between crystalline and amorphous states. It provided a strategy for designing new nontraditional π-gelators and piezofluorochromic materials via tuning the π–π interaction. [ABSTRACT FROM AUTHOR]

4-(Carbazol-9-yl)benzaldehyde could emit yellow RTP, which could last for 3 s because of efficient intersystem crossing. Moreover, multicolor luminescent switches could be realized by simply applying a mechanical force stimulus. [ABSTRACT FROM AUTHOR]

β-Iminoenolate boron complexes bearing non-planar phenothiazine (P2B and P16B) and phenothiazine-S,S-dioxide (PO2B and PO16B) have been synthesized. It was found that P2B and P16B gave ICT emission due to the strong electron-donating ability of phenothiazine, and no ICT emission was detected for PO2B and PO16B because of the weak electron-donating ability of phenothiazine-S,S-dioxide. In particular, P2B and P16B exhibited high-contrast MFC behaviors compared with that of PO2B. On account of the formation of π-aggregates in the as-synthesized crystals of P2B, several channels for the changes in emitting colors in different solid states were provided. The as-synthesized crystals of P2B emitting weak brown light could be changed into ground powders emitting deep orange-red light after grinding. When the ground powders were fumed with DCM for 5 s or heated at 160 °C for 3 s, the samples emitted yellow and yellowish green light, respectively. Although the π-conjugated skeleton of P16B was the same as that of P2B, the introduction of a long carbon chain led to different MFC properties. The as-synthesized crystals of P16B emitting yellow light could be changed into ground powders emitting orange light upon grinding. Particularly, the amorphous state of P16B could be self-recovered to the crystalline state when placed at room temperature for 5 min because the π–π interactions might be restrained by the long carbon chain, leading to low stability of the amorphous state. In the case of PO2B, low-contrast and reversible MFC properties were observed under grinding/fuming or heating treatment. No mechanofluorochromism was observed for PO16B since a long carbon chain was involved and no ICT emission happened. Therefore, we suggested that the introduction of a non-planar conjugated unit and the construction of a D–π–A system with ICT emission were favorable for designing MFC dyes with high-contrast changes in emitting colors in different solid states, and the introduction of a long carbon chain could improve the MFC reversibility so as to gain self-recovering MFC materials. [ABSTRACT FROM AUTHOR]

Three 2,5-dialkylcarbazole-substituted terephthalate derivatives, in which carbazole and ethoxylcarbonyl groups are used as electron-donating and -accepting moieties, respectively, were synthesized. Owing to the presence of steric hindrance between ethoxylcarbonyl and carbazole groups, three compounds show intense blue fluorescence in both solution and the solid state. The fluorescence quantum yields of compounds with octyl and hexadecyl groups in the solid state exceed 95%. Single-crystal structures of three compounds were obtained and used to interpret the strong emission in the solid state. More interestingly, three compounds exhibited alkyl length-dependent mechanofluorochromism. The compound with ethyl groups exhibited the largest spectral shift under force stimuli, but that with a hexadecyl moiety did not change its emission color after grinding. Because of strong fluorescence in solution and the solid state, we believe that they can be used as luminescent materials and sensors. [ABSTRACT FROM AUTHOR]

D–π–A type phenothiazine modified triphenylacrylonitrile derivatives PVTPAN, P3TPAN and P10TPAN have been synthesized. The three compounds exhibited AIE behaviors, and the emission enhancement of PVTPAN and P3TPAN, in which 3-position in phenothiazine was functionalized, was more significant than P10TPAN (10-position of phenothiazine was modified) with more twisted conformation. The single crystal structures revealed that the multiple intermolecular interactions, including π–π interactions and hydrogen bonds of C–H…π and C–H…N, would lock the molecular conformation and reduce the energy loss via non-radiative channels, leading to enhanced emission. Interestingly, the as-synthesized crystals of PVTPAN, P3TPAN and P10TPAN emitting strong yellow, yellowish-orange and yellowish-green light under UV irradiation could be transferred into powders emitting red, orange-red and orange light, respectively, after grinding. Such mechanochromism was reversible upon the treatment of grinding and heating/fuming with DCM. The XRD patterns suggested that the mechanochromism originated from the transition between the crystalline and amorphous states. It should be noted that the recovery time of the emission of the ground powders to that of crystals for P10TPAN was much shorter than those for PVTPAN and P3TPAN at the same temperature. Extremely, the emission of the ground powders of P10TPAN could recover at room temperature, but that of PVTPAN and P3TPAN could not. We suggested that such different mechanochromic behaviors of P10TPAN from PVTPAN and P3TPAN were coming from its more twisted conformation, which could lead to the exothermic peak appearing at lower temperatures and the easier molecular rearrangement of the amorphous state into crystals. Therefore, we could prepare the dyes with stable or reversible mechanochromism by tuning the molecular conformation. [ABSTRACT FROM AUTHOR]

Two linear carbazole-based conjugated compounds TC3T and PC3P with terminal triphenylamine and phenothiazine have been synthesized and showed selective gelation behaviors in some organic solvents upon ultrasound stimulation. SEM and TEM images of the xerogels revealed that 3D networks consisting of numerous nanofibers were formed in the gels of TC3T and PC3P. It should be noted that the obtained xerogels based on TC3T and PC3P emit strong blue and bluish green light, respectively, under UV irradiation. Upon exposure to the vapors of TNT and DNT, the emission of TC3T and PC3P in nanofiber-based films can be quenched obviously. The steady-state Stern–Volmer plots reveal that the fluorescence quenching of carbazole derivatives induced by aromatic nitro compounds is due to photo-induced electron transfer. Therefore, the emitting nanofibers obtained from the organogelation of linear carbazoles with terminal donors can be used as fluorescent sensors to detect explosives. [ABSTRACT FROM AUTHOR]

A series of 10,10′-bis(2-(N-alkylphenothiazine-3-yl)vinyl)-9,9′-bianthracene compounds (PVBAn, n = 2, 8, 12 and 16) with different lengths of N-alkyl chains have been designed and synthesized to systematically investigate the effect of chain length on their solid-state fluorescence properties. The results showed that these compounds emitted strong fluorescence in solution and in the solid state. Their emission wavelengths were also strongly affected by solvent polarity, indicating intramolecular charge transfer (ICT) transitions. Interestingly, the fluorescence emission and grinding-induced spectral shifts of PVBAn solids are alkyl length-dependent. PVBA2 shows the smallest fluorescence and absorption spectrum shifts under mechanical force stimuli. Homologues with longer alkyl chains exhibit similar mechanochromic behaviors and larger fluorescence contrasts after grinding. Moreover, the fluorescence emission of ground solid PVBA16 can recover at room temperature, but other compounds need high temperatures for fluorescence to be restored. Differential scanning calorimetry experiments reveal that the cold-crystallization temperature difference is responsible for thermal restoration behaviors. This work demonstrates the feasibility of tuning the solid-state optical properties of fluorescent organic compounds by combining the simple alteration of chemical structure and the physical change of aggregate morphology under external stimuli. [ABSTRACT FROM AUTHOR]

Carbazole and tert-butylcarbazole functionalized β-iminoenolate boron complexes CB and TCB with different mechanofluorochromic (MFC) properties have been synthesized. It was found that the as-synthesized crystal of CB emitted orange light under UV illumination because of the appearance of the emission from the monomers and the excimers. After grinding for a while, the ground powder 1 of CB emitted bright yellow light since the ratio of the emission intensity from excimers/monomers decreased. On further grinding for a long time, the excimers disappeared and the obtained amorphous ground powder 2 emitted dark green light. However, TCB emitted sky blue light in the as-synthesized crystal because no excimer was formed due to the steric hindrance of tert-butyl. After grinding, the amorphous ground powder of TCB emitted bright green light derived from excimers. It should be noted that the fluorescence quantum yield of TCB in an amorphous solid state reached 0.53, which was the highest one for the β-iminoenolate boron complexes that have ever been reported. In addition, the emission changes of CB and TCB in different solid states were reversible upon repeating the treatment of mechanical grinding and fuming with CH2Cl2. Therefore, the obtained β-iminoenolate boron complexes might be used as sensors and memory chips on the basis of the solid fluorescence response to external mechanical forces and organic solvents. [ABSTRACT FROM AUTHOR]

Two phenothiazine-based benzoxazole derivates (PVB and BPVB) were designed and synthesized, and their photophysical properties were studied and compared. The results showed that both compounds emitted strong fluorescence in solution and in the solid state. Their emission wavelengths were also strongly affected by solvent polarity, indicating intramolecular charge transfer (ICT) transitions. Interestingly, the two compounds exhibited different mechanochromism. The ground film of PVB without bromine atoms can self-cure and change into the original film within 15 min at room temperature. The fluorescence of the ground film for BPVB showed no changes for at least 2 weeks. Meanwhile, a higher contrast fluorescence change was observed for the solid film of BPVB with bromine atoms under grinding, although PVB and BPVB exhibited similar spectral red shifts after grinding. Based on the spectral results and single-crystal structures, a mechanochromic mechanism is given. [ABSTRACT FROM AUTHOR]

Nitrogen-rich cation 5-amino-1H-1,2,4-triazole-3-carbohydrazide and its derivatives were synthesized by a new molecular design strategy based on the energetic moiety combination. All derivatives were fully characterized by vibrational spectroscopy (IR), multinuclear (1H, 13C) NMR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), and impact and friction-sensitivity tests. The structures of compounds 1-4, 7 and 8 were further confirmed by single-crystal X-ray diffraction and six different types of crystal packing were surprisingly discovered. The results show that the extensive hydrogen bonding interactions between the cations and anions lead to a complex 3D network, which contribute greatly to the high density, insensitivity and thermal stability of the 5-amino-1H-1,2,4-triazole-3-carbohydrazide salts. It is also found that the cationic form of 5-amino-1H-1,2,4-triazole-3-carbohydrazide can decrease the sensitivity and elevate the nitrogen content of the target salts effectively. Some of these salts exhibit reasonable physical properties, such as good thermal stability (up to 407 °C) and reasonable impact sensitivities (IS = 5-80 J). In addition, theoretical detonation properties of the energetic salts obtained with EXPLO 5 (version 6.02) confirm them as competitively energetic compounds comparable to those of RDX or HMX.

A linear coplanar carbazole-based benzoxazole derivative without any auxiliary moieties could gelatinize organic solvents, and exhibited emission enhancement owing to the J-aggregate formation.

A triphenylamine-based benzoxazole derivative exhibits a low contrast piezofluorochromic behavior under external pressure, and a high-contrast fluorescence change induced by protonation can be observed.