Phase-controlled atom-photon entanglement in a three-level Λ-type closed-loop atomic system

We study the entanglement of dressed atom and its spontaneous emission in a three-level Λ-type closed-loop atomic system in a multi-photon resonance condition and beyond it.It is shown that the von Neumann entropy in such a system is phase-dependent,and it can be controlled by either the intensity or relative phase of applied fields.It is demonstrated that for the special case of the Rabi frequency of applied fields,the system is disentangled.In addition,we take into account the effect of Doppler broadening on the entanglement and it is found that a suitable choice of laser propagation direction allows us to obtain the steady state degree of entanglement(DEM) even in the presence of the Doppler effect.     

New regioisomeric naphthol-substituted thiazole based ratiometric fluorescence sensor for Zn2+ with a remarkable red shift in emission spectra

Ratiometric fluorescent chemosensors based on the position of ring annulation of the naphthol–thiazole moiety for quantification of zinc ions in aqueous ethanol were synthesized and investigated. It was found that sensor 3 exhibited a remarkably large red shift of 140 nm in emission upon complexation with Zn²⁺. A TD-B3LYP/6-31G (d,p) calculation was performed to characterize the nature of the fluorescence behavior of sensor 3 upon Zn²⁺ complexation. The combination of experimental and computational analyses provides a more complete understanding of the molecular level origin of these unique photophysical properties of this type of chemosensor.     

Synthesis of 1-aryl-substituted-4-chloroimidazo[1,2-a]quinoxalines catalyzed by PdCl2 in water

The reaction of 2-chloro-3-propargylaminoquinoxaline with various aryl iodides and bromides catalyzed by Pd–Cu in the presence of potassium carbonate as the base in water leads to the one-pot formation of 1-aryl-substituted-4-chloroimidazo[1,2-a]quinoxalines in moderate-to-high yields.     

Synthesis of new enantiomerically pure spirooxindolopyrrolizidines via a three-component asymmetric 1,3-dipolar cycloaddition reaction of azomethine ylides derived from isatin

An efficient, one-pot, three-component procedure for the synthesis of a small library of new chiral spirooxindolopyrrolizidines with high regio-, diastereo-, and enantioselectivity, from the 1,3-dipolar cycloaddition of azomethine ylides and optically active cinnamoyl oxazolidinone is described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the absence of any Lewis acids. The oxazolidinone chiral auxiliary is removed in a non-destructive manner. The reaction mechanism is discussed on the basis of the assignment of the absolute configuration of the cycloadducts, and on theoretical calculations.     

A new method for the synthesis of amides from imines

An efficient and straightforward method for the synthesis of amides by the reaction of imines and anhydrides in the presence of Et₃SiH/Zn is reported. Mild reaction conditions, good yields of products, short reaction times, and operational simplicity are advantages of this procedure.     

An Efficient Four‐component Synthesis of Spiro[indoline‐pyrazolo[4′,3′:5,6]pyrido[2,3‐d]pyrimidine]triones

A four‐component reaction in the presence of Alum [KAl(SO₄)₂·12H₂O] as an inexpensive and reusable catalyst using the ionic liquid as an effective green reaction media is reported.