The use of copper(I)-catalyzed “click” reactions of azides and alkynes for covalent layer-by-layer grafting on polyethylene is described. Water-soluble poly(N-alkylacrylamide) copolymers that contain pendant azide or alkyne groups that can be thermally separated from aqueous solutions were used to alternately “click” together azide and alkyne polymers via 1,2,3-triazole formation onto a prefunctionalized alkyne-containing surface. The layer-by-layer self-assembly process proceeds under ambient conditions and was followed by ATR-IR spectroscopy using control reactions to show that azide groups and copper catalysis are required for the assembly process. Post-graft functionalization of the hyperbranched assembly is used to demonstrate that the functional interfaces so formed can be further derivatized for other functions.

The petroglyph site in Jabal Jassasiyah Qatar is located approximately 60 km northeast of the capital city of Doha and has over 900 different types of petroglyphs. The most commonly found petroglyphs are cupules, which are almost always arranged in geometric patterns. A number of petroglyphs of boats are also found, usually seen from above, with a few seen in profile. As there is little evidence of what age to assign to these petroglyphs, samples of the calcium oxalate containing layers covering the petroglyphs were sent for radiocarbon dating to determine the minimum age they were created. The minimum ages of nine samples taken for analysis were found to be very short, the oldest minimum age being only 235 years BP (before present). No evidence was found for the petroglyphs dating back a few millennia as was previously postulated. Due to the lack of chronological data for Qatar’s archaeological past, the study data cannot completely rule out the petroglyphs dating back to ancient times

This article describes the synthesis of piperazine‐containing homopolymer systems via ring‐opening metathesis polymerization (ROMP). These systems were subsequently used as electron donors in the formation of charge‐transfer (CT) complexes. Using exo‐N‐(6‐bromohexyl)‐7‐oxabicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxamide as a starting material, monomers were synthesized to act as electron donors. The amine group at the “open” end of the piperazine was either left open or alkylated with various alkyl groups. The monomers' ability to act as electron donors and their polymerization rates were studied. After initial photometric titration studies using 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) as an electron acceptor proved that these monomers would act as electron donors, they were subsequently polymerized into homopolymers via ROMP. The experimental results showed that a methanol:chloroform mixed solvent system enhanced the rate of polymerization over a single solvent (chloroform) system. Studies also showed that the alkylated piperazine‐containing monomer had a faster rate of polymerization than the secondary piperazine monomer. These monomers were used to make piperazine‐containing homopolymers via ROMP and the resulting polymers, like the monomers, also functioned as electron donors. Potential functions of these polymers include electronics, solar cells, optical systems, and biological applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5034–5043, 2009

Even the most mundane changes to a published procedure can lead to laboratory accidents. This case study examines an incident that occurred when a researcher scaled up a reaction and modified the final step in a reaction workup by using acetone instead of water to wash a solid substrate. This scale-up and change in washing procedure small change led to an instantaneous reaction with residual bromine resulting in minor injuries to the researcher.

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