Thermally Stable Zinc Disalphen Macrocycles Showing Solid-State and Aggregation-Induced Enhanced Emission.

In order to investigate the solid-state light emission of zinc salphen macrocycle complexes, 7 dinuclear zinc salphen macrocycle complexes (1-7), with acetate or hexanoate coligands, are synthesized. The complexes are stable in air up to 300 °C, as shown via thermogravimetric analysis (TGA), and exhibit green to orange-red emission in solution (λem = 550-600 nm, PLQE ≤ 1%) and slightly enhanced yellow to orange-red emission in the solid state (λem = 570-625 nm, PLQE = 1-5%). Complexes 1, 2, 4, 5, and 7 also display aggregation-induced enhanced emission (AIEE) when hexane (a nonsolvent) is added to a chloroform solution of the complexes, with complex 4 displaying a 75-fold increase in peak emission intensity upon aggregation (in 0.25:0.75 chloroform:hexane mixture).

Ruthenium-catalyzed meta sulfonation of 2-phenylpyridines.

A selective catalytic meta sulfonation of 2-phenylpyridines was found to occur in the presence of (arene)ruthenium(II) complexes upon reaction with sulfonyl chlorides. The 2-pyridyl group facilitates the formation of a stable Ru-C(aryl) σ bond that induces a strong para-directing effect. Electrophilic aromatic substitution proceeds with the sulfonyl chloride to furnish a sulfone at the position meta to the chelating group. This new catalytic process offers access to atypical regioselectivity for reactions involving chelation-assisted cyclometalation.

The application of stop-flow microwave technology to scaling-out SNAr reactions using a soluble organic base.

A model S(N)Ar reaction which gives a range of substituted diaryl ethers has been re-developed to function with the soluble organic base DBU in the place of insoluble potassium carbonate. Manufacture of these diaryl ethers has then been achieved by scaling-out in an automated stop-flow microwave reactor to give productivities of >0.5 kg per day. Analogous reaction partners have also been scaled up in this reactor to extend the scope of the study. Brief comparison in a scale-up batch microwave reactor is also made. Lastly, continuous 24 h processing is reported in this small microwave stop-flow reactor, which requires no manual intervention once started.