Polycationic Open-Shell Cyclophanes: Synthesis of Electron-Rich Chiral Macrocycles, and Redox-Dependent Electronic States.

π-Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main-group electron-donating carbazolyl moieties or the π-expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure-of-eight topology as a result of the conjugation patterns of 2,2',7,7'-spirobifluorenyl in 1 and triarylamine-coupled aza[7]helicene-based building blocks in 2. This electronic nature of redox-active, carbazole-rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open-shell cyclophanes. Their redox-dependent electronic states of the resulting multispin polyradicals have been characterized by VT-ESR, UV/Vis-NIR absorption and spectroelectrochemical measurements. The singlet (ΔES-T=-1.29 kcal mol-1) and a nearly degenerate singlet-triplet ground state (ΔES-T(calcd)=-0.15 kcal mol-1 and ΔES-T(exp)=0.01 kcal mol-1) were proved for diradical dications 12+2⋅ and 22+2⋅, respectively. Our work provides an experimental proof for the construction of electron-donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors.

Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov., isolated from coastal sediment.

Two novel rod-shaped, Gram-stain-negative, aerobic and non-motile bacterial strains, designated M39T and C2-7T, were isolated from the coastal sediment of Xiaoshi Island, Weihai, PR China. Growth of strain M39T occurred at 15-37 °C, at pH 6.0-9.0 and in the presence of 1.0-9.0 % (w/v) NaCl. Strain C2-7T grew at 15-40 °C, at pH 6.0-8.0 and in the presence of 0.5-8.0 % (w/v) NaCl. Phylogenetic analysis based 16S rRNA gene sequences revealed that strains M39T and C2-7T belong to the phylum Bacteroidota. Based on the results of 16S rRNA gene sequence analysis, the closest relative of strain M39T was Robiginitalea marina KCTC 92035T (95.4 %), and the closest relative of strain C2-7T was Algoriphagus namhaensis DPG-3T (97.0 %). The percentage of conserved protein and average nucleotide identity values between strain M39T and some species of the genus Robiginitalea were 66.9-77.6% and 69.3-71.0 %, respectively, while those between strain C2-7T and some species of the genus Algoriphagus were 68.0-70.1% and 56.1-72.6 %, respectively. The major cellular fatty acids (>10 %) of strain M39T consisted of iso-C15 : 1 F, iso-C15 : 0 and iso-C17 : 0 3-OH, while those of strain C2-7T were iso-C15 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. MK-6 was the only respiratory quinone that was compatible with the genus of strain M39T. The predominant menaquinone of strain C2-7T was MK-7. The major polar lipids of strain M39T were phosphatidylethanolamine and glycolipids, and those of strain C2-7T were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. The DNA G+C contents of strains M39T and C2-7T were 46.9 and 40.8 mol%, respectively. Based upon the results presented in this study, strains M39T and C2-7T represent novel species of the genera Robiginitalea and Algoriphagus, respectively, for which the names Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov. are proposed with the type strains M39T (=MCCC 1H00498T=KCTC 92014T) and C2-7T (=MCCC 1H00414T=KCTC 92027T).

Winogradskyella vincentii sp. nov. and Winogradskyella alexanderae sp. nov., two novel bacteria isolated from intertidal sediment.

Two novel Gram-stain-negative, facultative anaerobic, chemoheterotrophic, non-motile and rod-shaped strains were isolated from intertidal sediment sampled at Xiaoshi Island, Weihai, PR China. Full sequence analysis of the 16S rRNA genes showed that the two strains were closely related to members of the genus Winogradskyella and the phylogenetic similarities to their closest relative, Winogradskyella aquimaris, were 96.7 and 95.8 %, respectively. The DNA G+C contents of strains 2Y89T and D23T were 33.3 and 35.1 mol%, respectively. The respiratory quinone detected in both strains was MK-6. The major fatty acids detected in strain 2Y89T were iso-C15 : 0 and iso-C15 : 1G, and in strain D23T they were iso-C15 : 1G, iso-C15 : 0 and iso-C17 : 03-OH. The principal polar lipids of strain 2Y89T mainly included phosphatidylethanolamine, aminoglycolipids, unidentified aminolipids, unidentified glycolipids and unidentified lipids; strain D23T was the same as strain 2Y89T except that it did not contain aminoglycolipids. Based on the phenotypic, chemical taxonomic, genotypic and phylogenetic features established in this study, we suggest that the new strains represent two novel species of the genus Winogradskyella, for which the names Winogradskyella vincentii sp. nov. (type strain 2Y89T=MCCC 1H00477T=KCTC 92034T) and Winogradskyella alexanderae sp. nov. (type strain D23T=MCCC 1H00462T=KCTC 92023T) are proposed.

Design and Synthesis of New Type of Macrocyclic Architectures Used for Optoelectronic Materials and Supramolecular Chemistry.

Supramolecular chemistry has received much attention for decades. Macrocyclic architectures as representative receptors play a vital role in supramolecular chemistry and are applied in many fields such as supramolecular assembly and host-guest recognition. However, the classical macrocycles generally lack functional groups in the scaffolds, which limit their further applications, especially in optoelectronic materials. Therefore, developing a new design principle is not only essential to better understand macrocyclic chemistry and the supramolecular behaviors, but also further expand their applications in many research fields. In recent years, the doping compounds with main-group heteroatoms (B, N, S, O, P) into the carbon-based π-conjugated macrocycles offered a new strategy to build macrocyclic architectures with unique optoelectronic properties. In particular, the energy gaps and redox behavior can be effectively tuned by incorporating heteroatoms into the macrocyclic scaffolds. In this Minireview, we briefly summarize the design and synthesis of new macrocycles, and further discuss the related applications in optoelectronic materials and supramolecular chemistry.

Red Emissive Double Aza[7]helicenes with Antiaromaticity / Aromaticity Switching via the Redox-Induced Radical Cation and Dication Species.

We herein present the synthetic approach to a new antiaromatic double aza[7]helicene C that features NN-embedded polycyclic aromatic hydrocarbons (PAHs). This heteroatom-doped helicene showed a rarely obtained long-wavelength emission and far-red circularly polarized luminescence (CPL) in the solid state. These optical and chiroptical properties could be ascribed to both the NN-PAH core structure and the further extension through angular ring fusions. Such a unique electronic structure also culminated in facile chemical oxidations of neutral C to the positively charged chiral radical (C⋅+ ) and dication species (C2+ ). Interestingly, DFT computations revealed that the pyridazine central core showed an antiaromaticity-to-aromaticity switching, in contrast to the inversed transition for the helical periphery in cationic states. The reported approaches are anticipated to lead to the development of further redox-active chiral systems for potential applications in chiroptoelectronics, spintronics as well as fluorescent bioimaging.

Expanding new chemistry of aza-boracyclophanes with unique dipolar structures, AIE and redox-active open-shell characteristics.

π-Conjugated macrocycles involving electron-deficient boron species have received increasing attention due to their intriguing tunable optoelectronic properties. However, most of the reported B(sp2)-doped macrocycles are difficult to modify due to the synthetic challenge, which limits their further applications. Motivated by the research of non-strained hexameric bora- and aza-cyclophanes, we describe a new class of analogues MC-BN5 and MC-ABN5 that contain charge-reversed triarylborane (Ar3B) units and oligomeric triarylamines (Ar3N) in the cyclics. As predicted by DFT computations, the unique orientation of the donor-acceptor systems leads to an increased dipole moment compared with highly symmetric macrocycles (M1, M2 and M3), which was experimentally represented by a significant solvatochromic effect with large Stokes shifts up to 12 318 cm-1. Such a ring-structured design also allows the easy peripheral modification of aza-boracyclophanes with tetraphenylethenyl (TPE) groups, giving rise to a change in the luminescence mechanism from aggregation-caused quenching (ACQ) in MC-BN5 to aggregation-induced emission (AIE) in MC-ABN5. The open-shell characteristics have been chemically enabled and were characterized by UV-Vis-NIR spectroscopy and electron paramagnetic resonance (EPR) for MC-BN5. The present study not only showed new electronic properties, but also could expand the research of B/N doped macrocycles into the future scope of supramolecular chemistry, as demonstrated in the accessible functionalization of ring systems.

A New Platform of B/N-Doped Cyclophanes: Access to a π-Conjugated Block-Type B3 N3 Macrocycle with Strong Dipole Moment and Unique Optoelectronic Properties.

We herein describe a new design principle to achieve B/N-doped cyclophane where an electron-donor block of three triarylamines (Ar3 N) and an acceptor block of three triarylboranes (Ar3 B) are spatially separated on opposite sides of the π-extended ring system. DFT computations revealed the distinct electronic structure of the block-type macrocycle MC-b-B3N3 with a greatly enhanced dipole moment and reduced HOMO-LUMO energy gap in comparison to its analogue with alternating B and N sites, MC-alt-B3N3. The unique arrangement of borane acceptor Ar3 B and amine donor Ar3 N components in MC-b-B3N3 induces exceptionally strong intramolecular charge transfer in the excited state, which is reflected in a largely red-shifted luminescence at 612 nm in solution. The respective linear open-chain oligomer L-b-B3N3 was also synthesized for comparison. Our new approach to donor-acceptor macrocycles offers important fundamental insights and opens up a new avenue to unique optoelectronic materials.

Oligotriarylamine-Extended Organoboranes with Tunable Electron-Donating Strength by Changing the Number of Donor Units.

Triarylborane (Ar3B) and triarylamine (Ar3N) have been widely employed to construct electronically different donor-acceptor (D-A) systems. Herein, we describe a series of A-D-A-type luminescent organoboranes L-B2Nn (n = 1, 3, 5) that show an increased number of Ar3N units as electron donors and two terminal Ar3B as acceptors. When the Ar3N moieties were extended from one to five units, their electron-donating strength was gradually enhanced and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps could also be tuned, which was further reflected in the red-shifted emissions from blue (λem = 458 nm) to orange (λem = 595 nm) with a decrease in Egap(elect) from 3.19 to 2.61 eV. L-B2N5 showed a huge Stokes shift (∼14 057 cm-1) and a considerably bright emission with an enhanced solid-state quantum efficiency (ΦS = 98%) compared with the other members. L-B2N3 and L-B2N5 exhibited aggregation-induced emissions (AIEs), and an apparent solvatochromic shift was also observed in the emission spectra as the solvent was changed from hexane to tetrahydrofuran (THF) (430 → 595 nm). In addition, the donor-acceptor charge-transfer character in these organoboranes caused a thermally responsive emission over a broad range.

MiR-216b suppresses cell proliferation, migration, invasion, and epithelial-mesenchymal transition by regulating FOXM1 expression in human non-small cell lung cancer.

Background/aims: MiR-216b and forkhead box M1 (FOXM1) were demonstrated to exert their biological effects on the development and progression of tumors. This study aimed to investigate the expression and role of miR-216b and FOXM1 in tissues and cell lines of non-small cell lung cancer (NSCLC). Methods: The expressions of miR-216b and FOXM1 in NSCLC tissues and cells were detected by qRT-PCR and Western blot analysis. Cell proliferation was measured by CCK-8 assay. Cell migration and invasion were confirmed by Transwell assay. Finally, the bioinformatics and dual-luciferase reporter assay were conducted to validate the relationship of miR-216b and FOXM1. Results: Compared with normal tissues and cells, the expression of miR-216b was obviously decreased in NSCLC tissues and cells. However, the expressions of FOXM1 mRNA and protein were significantly increased, and negatively correlated with the expression of miR-216b. Multivariate Cox's regression analysis suggested that miR-216b or FOXM1 expression was an independent prognostic factor for patients with NSCLC. MiR-216b overexpression remarkably repressed cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of NSCLC cells. The bioinformatics and dual-luciferase reporter assay validated that the 3'-untranslated region (3'-UTR) of FOXM1 mRNA was indeed a direct target of FOXM1. In vitro, overexpression of FOXM1 partially eliminated inhibitory effects of miR-216b on cell proliferation, migration, and invasion, whereas inhibition of FOXM1 contributed to inhibitory effects mediated by miR-216b. Conclusion: MiR-216b inhibits cell proliferation, migration, invasion, and EMT by targeting the expression of FOXM1 in human NSCLC. These findings suggested a potential therapeutic role of miR-216b in patients of NSCLC.