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The Baylis-Hillman reactions of various aryl aldehydes with methyl vinyl ketone at temperatures below -20oC using Lewis acids such as titanium (IV) chloride, boron (III) chloride or zirconium (IV) chloride in the presence of a catalytic amount of selected amines used as a Lewis bases afford the chlorinated compounds 1 as the major product in very high yields. Acrylonitrile can also undergo the same reaction to give the corresponding chlorinated product in moderate yield. A plausible reaction mechanism is proposed. However, if the reaction was carried out at room temperature (ca. 20oC), then the Z-configuration of the elimination product 3, derived from 1, was formed as the major product.

Single molecule detection of an airborne single oxygen [(super)1][O.sub.2] molecule diffused from the surface of Ti[O.sub.2] nanoparticles using total internal reflection fluorescence microscopy (TIRFM) is described. It is seen that the current nanosensor using single terrylenediimide (TDI) molecules, which has a detectable number of about 1000 [(super.1)][O.sub.3] molecules in the 70 x 70 [mu][m.sup.2], can easily detect the single [.sup.1O.sub.3] molecule at the distance of >1000 [mu]m from the place of its creation in ambient air.

In this article, we described the use of an easily available polymer‐based hafnium chloride and montmorillonite KSF catalyst (HfCl 4 /KSF‐polyDMAP) in transamidation under relatively mild conditions. This metal catalyst can be easily recovered and reused in this reaction to give the corresponding amides in good yields. [ABSTRACT FROM AUTHOR]