Alexander K. EltyshevNadezhda V. ChernyshevaArtem S. Minin
13页
查看更多>>摘要：This paper reports the one-pot synthesis of a rare type of mesoionic compounds, which are condensed rneso-ionics. A series of new bicyclic arylthienotriazoliumolates was synthesized by an improved synthetic method. This approach has a large scope of starting materials and was used to obtain diverse structures with outstanding photophysical properties. The pattern of substituents decorating the mesoionic ring was the important factor determining the electronic distributions of the synthesized compounds. Pull-pull (A-π-A), push-push (D-π-D), pull-push (A-π-D), and push-pull (D-π-A) systems were designed, synthesized and their absorption, emission, stability, and biological behavior were studied. Quantum chemical calculations were performed to deepen the knowledge about the absorption and emission properties of these systems and explain their unusual geometries and electronic structures. Confocal microscopy experiments showed that thienotriazoliumolates easily penetrated into riving cells and selectively accumulated near the cell membrane, Golgi apparatus, and endoplasmic reticulum.
查看更多>>摘要：In this article, we report a chloro-rhodamine (ClR) dye as a potential novel probe scaffold that possesses a specific intra-subspiral cyclization behavior: the acetylation of ClR (CIR-Ac) features a closed-loop structure in an aqueous solution, while the ClR itself is an open-loop structure. ClR-Ac is colorless and completely nonfluores-cent, while ClR is yellowish and strongly fluorescent. This discovery has led to the development of a general design strategy to develop highly sensitive fluorescence probes for peptidase. We designed and synthesized the probe CIR-Glu by peptidase represented by y-glutamyl-transpeptidase (GGT) to verify this strategy. Experimental results show that ClR is easier to synthesize and has better environmental pH stability than the GGT probe based on HMRG. Furthermore, in addition, we expect that ClR-based probes will be widely used for the detection of peptidases and other analyses.
查看更多>>摘要：Superoxide anions (O2~-), which are precursors of reactive oxygen species (ROS), are mainly produced in the mitochondria. This precursor of ROS is involved in both pathological and physiological processes, hence their role in many disease conditions and complications is pivotal. Though with time they are capable of being changed into related ROS species, their quantification will aid in targeting and complete eradication through numerous chemical reactions. The presence of a high reduction potential fosters the innate anionic charge to impede their reactivity with centers considered to be electron-rich. Though there are numerous quantification processes for the O2-, the use of a fluorescent probe which serves as a low invasive approach with deep tissue penetration and prolonged time of analysis has emerged to change the status quo when it comes to the way of analyzing O2~-. Although, in some cases, this approach happens to be faced with some difficulties such as autofluorescence, photobleaching, shallow penetration, etc. This review seeks to give a general overview of the recent development in this research field, outcomes, and the yield of employing Two-photon, NIR, and other ratiometric fluorescent probes, their ability to sensitively and selectively target O2~-in vivo and in vitro.
查看更多>>摘要：The biomass-based carbon materials with heteroatomic regulation, hierarchical structure, remarkable porosity, excellent conductivity and good stability are promising energy materials for supercapacitors. Herein, we designed and synthesized the multidimensional morphology controllable carbon materials by activation approach using pervasive watermelon rind as the carbon source. Interestingly, the carbon materials revealed diverse dimensional morphology characterizations for 3D hierarchical honeycomb nanoporous carbon architecture (CNP), 2D carbon nanoflake model (CNF) and ID needle-shaped carbon nanobars (CNB) with/without different dopants. The CNB energy material indicated a large specific area for 879.18 m~2 g~(-1), and the flexible electrode showed excellent areal capacitance for —2245 F cm~(-2) at 1 mA cm~(-2). Moreover, the constructed flexible symmetric device shows outstanding cycling stability for 99.5% after 20,000 cycles, superior energy density for 0.12 mWh cm~(-2) at a power density of 0.52 mW cm-2. This work provides a facile and sustainable approach to synthesize high-performance energy materials for supercapacitor.
查看更多>>摘要：Ellagic acid (H4EA), a natural polyphenol, is an ideal candidate in the search for sustainable materials for use in organic electronics due to its strong resemblance to other well-known polyaromatic hydrocarbons being employed in the field such as pyrene. The work presented herein focuses on the functionalization of H4EA with aryl moieties via SnAt reactions, thereby affording a facile two-step approach to tailor the optoelectronic properties of the resulting organic semiconductors. In particular, pyrazine and quinoxaline moieties were selected to due to the presence of additional nitrogen atoms along with the it-system afforded through their molecular frameworks. The results presented demonstrate that such functionalization of H4EA does in fact impact the finetuning of the photophysical and structural properties of the resulting materials. Although performance was less than ideal when implemented into thin-film transistors, this may be attributed to poor film morphology. Nonetheless, this work introduces new green materials to the field, through which facile functionalization can be realized.
Stuart AikenGeorgina K. ArmitageOrlando D.C.C. de Azevedo
24页
查看更多>>摘要：A series of photochromic 2,2,4,6-tetraaryl-2H-benzo[h]chromenes have been efficiently synthesised by two complementary strategies employing the condensation of l,l,3-triarylprop-2-yn-l-ols with 4-substituted 1-naphthols and Suzuki cross-coupling chemistry. The novel 1,1,3-triarylpropynols were readily obtained either by the addition of an arylacetylide to the requisite benzophenones or by a Sonogashira coupling of a halobenzene with a preformed l,l-diarylprop-2-yn-l-ol. The tetraarylbenzochromenes which possessed a strong electron withdrawing aryl moiety at C-4 exhibited good room temperature photochromism. The combination of a strong electron donating aryl group at C-6 with a strong electron withdrawing aryl group at C-4 resulted in the generation of a photomerocyanine which exhibited two absorption bands in the visible region of the electromagnetic spectrum, rather than one broad band when the C-6 aryl group was only weakly electron donating. Remarkably inverting the electronic nature of the C-4 and C-6 aryl groups resulted in the inhibition of photochromism and instead led to fluorescence. TD-DFT calculations were used to rationalise the shift from photochromism to fluorescence.
查看更多>>摘要：Metal-ligand axial coordination of zinc(II) phthalocyanines is an efficient strategy for regulation of structures and properties. In this work, we designed and prepared four unsubstituted zinc(II) phthalocyanine (ZnPc) dimer-based supramolecular complexes (1-4) via axtial coordination with bipyridine derivatives. Single crystal X-ray analysis revealed that the four novel complexes were dimeric (i.e. ZnPc-ligand-ZnPc), with H-shape for 1, saddlelike for 2, and Z-shapes for 3 and 4. It's interesting that a pair of saddle-like dimers of 2 crossed each other to form an interlocked tetramer structure. Furthermore, 3 and 4 were dense stacking because of their semirigid ligands, which significantly enhanced the intermolecular interactions. Intriguingly, in the crystal structure of 4, the naphthalimide ring of the ligand embedded into two neighboring phthalocyanine macrocycles, resulting in a slipped sandwich structure of ZnPc-naphthalimide-ZnPc with double π—% interactions. More importantly, the strong intermolecular interactions led to very broad absorption spectra in vis-NIR region, quenched fluorescence, and highly efficient photothermal effect. Upon irradiation, 3 and 4 could reach up to 85.7 °C and 89.2 °C, respectively, enabling them to serve as outstanding photothermal conversion materials used for photothermal imaging and therapy.
查看更多>>摘要：The effect of synergistic structural engineering (asymmetric side chains and backbone fluorination) for polymer donors in photovoltaic applications is investigated in this study. Six isoindigo (IID)-based polymer donors with slightly different side-chain and backbone designs are composed of a bithiophene (BT) or fluorinated bithiophene moiety to form two series of polymers [PII2T (P1-P3) and PII2TF (P4-P6)] while symmetric/asymmetric side-chain combinations are composed of decyltetradecane branched alkyl side chain (DT) and siloxane-terminated side chain (SiO-C8). The results indicate the different side chain design and backbone fluorination modulate the energy levels, crystalline properties, and molecular packing behaviors of the polymers. P2 and P5 with asymmetric side chains are showed to deliver the highest power conversion efficiency (PCE) in the respective series of PII2T and PII2TF. The morphological analyses reveals that the mismatched side-chain geometry results in a face-on dominated packing to yield superior device performance. Meanwhile, the fluorinated polymers (P4-P6) show superior performance than the corresponding non-fluorinated polymers (P1-P3). Moreover, backbone fluorination largely reduces the performance difference between the polymers with symmetric side chains and asymmetric sides chains. This work demonstrates that the synergistic effect of asymmefric side chains and backbone fluorination can be a rational design towards high-performance conjugated polymers.
Artem D. PugachevNadezhda I. MakarovaIlya V. Ozhogin
15页
查看更多>>摘要：Novel photochromic spiropyrans (SPPs) of the indoline series with fluorine substituents and cationic fragments or formyl groups at positions 6' and 8' of the 2H-chromene moiety were synthesized using a simple one-pot method. Molecular structures of 8'-fluorine-substituted compounds were refined by single-crystal X-ray, which revealed that both SPPs exist in their merocyanine forms in a crystalline state. It was established, that structure-related photochromic transformations of studied SPPs include: positive photochromism for SPPs with a vinyl-3H-indolium fragment or a formyl group at position 8' of the benzopyran moiety; negative photochromism for SPP with a vinyl-3H-indolium fragment at position 6' of the molecule; both positive and negative photochromism for SPP with a formyl group in position 6' of the molecule, demonstrating the properties of photochromic "balance". The polychromogenicity of the obtained compounds allows them to be considered as fluorescent molecular switches and bipolar absorption switches.
查看更多>>摘要：This paper seeks to elucidate the influence on the surface wettability of a variety of substituents located in different positions of the perylene bisimide (PBI) core (ortho versus imide) with distinct electron-donor or-withdrawing character and diverse steric demand, using for this more than 20 planar PBIs. The correlation between the polarity of the individual functional group on the PBI and the surface wettability has been addressed by means of substituent descriptors in terms of Hansch-Fujita k parameter, Hammett σ_(meta) and σ_(para) constants, and steric parameters (Taft-Dubois Es' and Charton o). With these parameters, a quantitative structure-property relationship (QSPR) analysis has been performed using multivariable linear regression (MLR) fittings. The relationship of Surface Energy, determined by the static contact angle method with three different solvents, to structural properties of PBIs is described. As well, the polar and dispersive contributions have been determined. For planar PBIs, a predominant influence of the substituents in the imide position on the surface wettability has been found despite of the electronic nature and steric hindrance of the substituents simultaneously located in ortho positions. This effect is more pronounced with the longer alkyl substituents at the imide position. This study paves the way for a rational chromophore design considering the on surface behavior, which will ultimately condition the contact and thus their performance in optoelectronic devices.
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