Acid-induced tunable white light emission based on triphenylamine derivatives

A series of triphe nylamine(TPA)derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect.On account of the existence of pyridine units,these TPA derivatives exhibited acid-induced tunable multicolor fluorescence emission including white light emission.In addition,acid-induced fluorescence regulation of these compounds has been also realized in the solid state,which enable them to be successfully constructed the stimuli-responsive fluorescent films and fluorescent inks for inkjet printing.

Reversible fluorescent probes for chemical and biological redox process

Oxidation and reduction are important chemical and biological processes. The redox state is related with physical functions and health. Thus, it is meaningful to develop tools for study the redox process.Fluorescence is a powerful method to connecting the microcosm and macrocosm. In this review, we discuss the recent progress of reversible fluorescent probes for chemical and biological redox process according to different active centers.

Fluorescence-resonance energy transfer(FRET)within the fluorescent metallacycles

During past few years,the construction of fluorescent metallacycles featuring the fluorescenceresonance energy transfer behavior has attracted extensive attention due to their diverse applications such as real-time monitoring the dynamics of coordination-driven self-assembly,photoswitching fluorescence-resonance energy transfer,and light-controlled generation of singlet oxygen for cancer therapy.This review focuses on the recent advances on the design principles,preparation methods,optical properties,and the wide applications of fluorescent metallacycles with the FRET property.

One-pot enantioselective construction of 3,4-dihydro-2H-1,4-oxazines over Ru/Au relay catalysis and its mechanistic serendipity

The preparation of enantiomerically pure 1,4-oxazines remains a continuous challenge in synthetic chemistry because of their potential application in the total synthesis of morpholines.Herein,a one-pot asymmetric transfer hydrogenation/cyclization enantio-relay process catalyzed by Ru and Au bimetallic catalysts was developed.This enantio-relay process firstly allows the asymmetric transfer hydrogenation of alkynones to form chiral alkynols in the presence of(S,S)-mesityleneRuClTsDPEN(TsDPEN=N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine)and then the chiral alkynols could be converted into 3,4-dihydro-2H-1,4-oxazines in moderate to good yields with excellent enantioselectivity retention accompanied by AuCl(PPh_(3))/AgNTf_(2) and HCOOH.A series of sulfonamide-tethered alkynones were well tolerated in this process.Mechanistic studies indicated that the alkynols formed in the first step were initially transformed into a methylenemorpholine intermediate when AuCl(PPh_(3))/AgNTf_(2) and HCOOH were added,which can be further isomerized into chiral 3,4-dihydro-2H-1,4-oxazines with the addition of a second HCOOH.This protocol offers not only a practical method to access 3,4-dihydro-2H-1,4-oxazines from alkynones in an enantioselective version,but also enriches the arsenal of gold chemistry from a mechanistic point of view.