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A new approach for the synthesis of C3-symmetric proazaphosphatranes with chirality at the bridging methylene positions is reported. [Copyright &y& Elsevier]

Over the past few years, transition metal-mediated oxidative cross-coupling reactions have emerged as a versatile method to construct C–C bonds. However, most of the precedents require high-priced precious metal catalysts such as Rh, Pd, and Ru in combination with a stoichiometric amount of metal oxidant including copper and silver salt. Recently, stoichiometric copper or silver salt-mediated oxidative C–H/C–H cross-coupling reactions in the absence of high-priced metal catalyst have shown up prominently. This short review covers the latest progress in the applications of this emerging strategy, highlights their advantages and limitations, and provides a comprehensive overview on existing procedures and employed methodologies. [ABSTRACT FROM AUTHOR]

Abstract: New squaraine-based chemosensors SQ1 and SQ2 functionalized with 2-picolyl units were first synthesized and used as highly selective and sensitive colorimetric and fluorometric dual-channel sensors for Cu2+-specific recognition in aqueous systems. Among a series of individual metal ions, only Cu2+ could result in dramatic color changes. We also evaluated their capability of biological applications and found that SQ2 could be successfully employed as a Cu2+-selective probe in the fluorescence imaging of living cells. [Copyright &y& Elsevier]

Selective labelling and high-fidelity tracking of intracellular lipid droplets (LDs) can provide direct insight into pathological processes associated with abnormal lipid metabolism and therefore are of great value. We herein present a novel imidazole-based probe, TITM , which shows the aggregation-induced emission property and a remarkable fluorescence increase in sunflower oil than in water. With the advantages of good lipophilicity, biocompatibility, and LDs-targeted specificity, TITM allows the real-time and long-term tracking of dynamic LDs in living cells with high-resolution imaging performance. By establishment of LDs-related atherosclerosis (AS) and fatty liver mouse model, the imaging performance of TITM at pathological tissue level is well studied to show impressive selectivity and resolution. [Display omitted] • An imidazole-based probe is disclosed to show a remarkable fluorescence increase in sunflower oil than in water. • The probe allows real-time and long-term tracking of lipid droplets in living cells with high-resolution imaging. • The fluorescence probe shows good biocompatibility and photostability. • The probe can visualize abnormal lipid droplets accumulation in mouse atherosclerotic plaques and fatty liver tissues. [ABSTRACT FROM AUTHOR]

As 3-aza-1,5-enynes, internal and terminal alkyne-bearing tertiary enamides underwent an efficient Au(I)-catalyzed 6- endo - dig cyclization reaction to afford a variety of di- to penta-substituted 1,2-dihydropyridine derivatives in high yields. The cyclization proceeds through a cascade comprising an intramolecular nucleophilic addition of enaminic carbon to alkyne–gold(I) complex, deprotonation, and protodeauration steps. Au(I)-catalyzed tertiary enamide–alkyne cyclization coupled with consecutive oxidative aromatization provided a straightforward route to polysubstituted pyridines. [ABSTRACT FROM AUTHOR]

Abstract: The first example of an AIE active BF2dbm derivative with a single dimethylamino group connecting to the phenyl ring was revealed. It also showed capability of sensing HCl gas both in solution and in the solid state. [Copyright &y& Elsevier]

Herein disclosed the adjustment of the dual emission of keto and enol forms of excited-state intramolecular proton transfer (ESIPT) emitters via intramolecular charge transfer (ICT) effects. Introducing electron-donating triphenylamine (TPA) and electron-withdrawing triphenylboron (TPB) substituents into the para -position of the phenolic hydroxyl group or the side of the oxazole of 2-(2′-hydroxyphenyl)oxazole skeleton endows the resulting compounds (6a - 6d) with different photophysical properties. Owing to the ICT effect from electronic donor to acceptor, introducing TPA into the side of oxazole and TPB into the para -position of phenolic hydroxyl is conducive to an enol-form emission (6a). Exchanging the two substituents, namely introducing TPB into the side of oxazole and TPA into the para -position of phenolic hydroxyl, would be beneficial to a keto-form emission (6b). Synchronously introducing two identical substituents, whether TPA or TPB, into two sides of 2-(2′-hydroxyphenyl)oxazole skeleton (6c and 6d) would lead to the dual emission of keto and enol forms due to the excited-state equilibrium of ESIPT reactions, which are further verified by DFT calculation. The organic light-emitting diode (OLED) devices with 6a and 6c as emitters were fabricated, both of which exhibit hybridized local and charge transfer (HLCT) excited-state characters with high external quantum efficiencies (EQEs) of 4.9% and 5.6%, respectively. • The adjustment of keto/enol emission of ESIPT emitters was systematically investigated for the first time. • ICT effect was deduced to be the main driving force to lead to the different luminescence properties of these ESIPT emitters. • The excited-state equilibrium of ESIPT reactions is verified by DFT calculation. • OLEDs based on ESIPT emitters exhibit high external quantum efficiencies. • The HLCT characters of ESIPT emitters were confirmed by experimental data and theoretical calculations. [ABSTRACT FROM AUTHOR]

The rhodium(I)-catalyzed enantioselective hydrogenation of E- and Z-configured β-acylamido β-alkylacrylates as well as of isomeric mixtures has been investigated. As ligands 1,2-bisphospholanes like DuPHOS, BPE and Me4-BASPHOS have been tested, but also diphosphines forming seven-membered chelates such as DIOP. The effect of additional oxy groups in the diphosphine ligand on rate and enantioselectivity was likewise elucidated. In general, with all catalysts screened the hydrogenation is strongly sensitive to the E/Z-geometry of the substrate. E-Substrates are converted with good or excellent enantioselectivites into the desired β-amino acid derivatives. The hydrogenation of Z-substrates showed the known H2-pressure dependency of the ee. [Copyright &y& Elsevier]

Lipid droplets (LDs) targeted fluorescence probe have been believed to be an effective tool for diagnosis and therapy of some tumors with abnormal lipid metabolism, while there are very few probes with simultaneous high efficiency in LDs imaging and inhibiting tumor proliferation. Herein we present a biheteroaryl-bridged fluorescence probe with aggregation-induced emission (AIE) characteristic, which show dual functions of LDs-specific bioimaging and photodynamic therapy (PDT) based on human clear cell renal cell carcinoma (ccRCC) tumor cells and clinical samples, both rich in LDs. The highly LDs-specific targeting capability, good biocompatibility, excellent photostability and imaging resolution of the AIE probe in ccRCC tumor cells make it considerably attractive to commercially available LDs-specific dyes. Notably, the fluorescence imaging in fresh human ccRCC tumor tissues further proves its outstanding LDs-targeting specificity and demonstrates its power as a bio-probe for clinical diagnosis in vitro and in vivo. Confirmatory experiments suggest a superior PDT efficacy of the AIE probe in ccRCC tumor cells in comparison to those LDs-poor tumor cells and normal cells without LDs. Mechanism studies further reveal the presented AIE probe enables to induce the DNA damage and cell apoptosis by reactive oxygen species generation, resulting in desirable therapeutic efficiency for clinical ccRCC tumor cells upon visible light irradiation. Image 1 [ABSTRACT FROM AUTHOR]