A new highly selective fluorescent sensor based on a novel fluorophore for cyanide and its applications in bioimaging.

A novel highly active fluorescence chemical sensor (TBI) for CN- was synthesized based on triphenylamine-benzothiazole as a new fluorophore, and was used for the first time as a fluorophore for detection of CN- . Fluorescence quantum yield of the probe clearly increased when using triphenylamine-benzothiazole as the group. The probe possessed good selectivity towards CN- and had anti-interference ability over common ions. After adding CN- , the UV-visible spectrum of TBI changed clearly and underwent a dramatic colour change from red to colourless, which could be observed clearly by the naked eye. The limit of detection for CN- was calculated to be 2.62 × 10-8 M, which was well below the WHO cut-off point of 1.9 µM. The novel probe displayed fast sensing of CN- . The detection mechanism was a nucleophilic addition reaction between CN- and a carbon atom -C = N- in indole salt. The π-conjugation and intramolecular charge transfer (ICT) transition in the TBI molecule were destroyed by this addition, which resulted in a change of fluorescence before and after the addition of CN- . The mechanism was verified using theoretical calculation, 1 H NMR titration, and mass spectra. In addition, the probe showed low cytotoxicity and could be used for biological imaging in HeLa cells.

Carbamoyl Fluoride-Enabled Enantioselective Ni-Catalyzed Carbocarbamoylation of Unactivated Alkenes.

A carbamoyl fluoride-enabled enantioselective Ni-catalyzed carbocarbamoylation of unactivated alkenes was developed, providing a broad range of chiral γ-lactams bearing an all-carbon quaternary center in 45-96% yield and 38-97% ee.

Enantioselective Ni-Al Bimetallic Catalyzed exo-Selective C-H Cyclization of Imidazoles with Alkenes.

A Ni-Al bimetallic catalyzed enantioselective C-H exo-selective cyclization of imidazoles with alkenes has been developed. A series of bi- or polycyclic imidazoles with ß-stereocenter were obtained in up to 98% yield and >99% ee. The bifunctional SPO ligand-promoted bimetallic catalysis proved to be critical to this challenging stereocontrol.

Ni-catalyzed hydroarylation of alkynes with unactivated ß-C(sp2)-H bonds.

Hydroarylation of alkynes with unactivated C(sp2)-H bonds via chelated C-H metalation mainly occurs at γ-position to the coordinating atom of directing groups via stable 5-membered metallacycles, while ß-C(sp2)-H bond-involved hydroarylation has been a formidable challenge. Herein, we used a phosphine oxide-ligated Ni-Al bimetallic catalyst to enable ß-C-H bond-involved hydroarylations of alkynes via a rare 7-membered nickelacycle.

Ni-Catalyzed Dual C-H Annulation of Benzimidazoles with Alkynes for Synthesis of π-Extended Heteroarenes.

Transition metal catalyzed dual C-H activation and annulation with alkynes was an attractive protocol to construct polycyclic π-extended structures. However, most of them were dominated by noble metal catalysts. Disclosed herein was the study of base-metal Ni-catalysis for dual C-H annulation of N-aromatic imidazole, which produced a range of desired polycyclic aza-quinolines in 48-95% yields. The use of bifunctional phosphine oxide ligand proved to be critical for success.

Reasons for patient non-compliance with compression stockings as a treatment for varicose veins in the lower limbs: A qualitative study.

The study aims to explore the comprehensive reasons for patients' non-compliance with graded elastic compression stockings (GECS) as the treatment for lower limb varicose veins. Phenomenological analysis was applied in this qualitative study. The patients diagnosed with lower limb varicose veins and undergoing elective surgery who showed non-compliance with GECS as the treatment were invited to have semi-structured, in-depth, face-to-face interviews. Colaizzi method was employed to analyze the data for emerging themes associated with the reasons for patients' non-compliance. Four main themes and nine subthemes related to the reasons for non-compliance with GECS for lower limb varicose veins were summarized. The main themes that emerged were (1) gaps in the knowledge of GECS therapy as a treatment for lower limb varicose veins, (2) few recommendations from the doctors and nurses, (3) disadvantages of GECS, and (4) sociopsychological factors. These themes provide data for policy and planning to improve patients' compliance with GECS in China. Patients, healthcare professionals, and policy makers should share the responsibility to improve patients' compliance with GECS therapy.