EPR spectroscopy and product isolation have been used to investigate the initiation of spontaneous copolymerizations of donor and acceptor monomers. The results establish the presence of tetramethylene diradicals as the only experimentally supported intermediates in the initiation for these spontaneous copolymerizations. No evidence supporting a Mayo cycloaddition mechanism, electron transfer, or charge-transfer complex initiation was found. The reaction of an olefin activated by three electron-accepting groups, such as dimethyl cyanofumarate, methyl 3,3-dicyanoacrylate, or trimethyl ethylenetricarboxylate, with a styrene having unsubstituted ortho positions was used in this study. In the presence of the spin trap 2-methyl-2-nitrosopropane (t-BuNO), aminoxyls with characteristic EPR spectra of high intensity were detected. Reaction of 4-methoxystyrene and dimethyl cyanofumarate in the presence of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) led to a diamagnetic 1:1:1 adduct, 4-cyano-6-methoxy-3,4-dimethoxycarbonyl-1-piperidinyloxytetrahydronaphthalene, which was subjected to an X-ray crystallographic study. Treatment of the TEMPO adduct with t-BuNO in chloroform gave a solution containing TEMPO and the same aminoxyl as that formed from 4-methoxystyrene, dimethyl cyanofumarate, and t-BuNO. These aminoxyls were assigned the structure of spin adducts of tetrahydronaphthalen-1-yl radicals, formed by initial trapping of the diradical of the donor and acceptor olefin at the more reactive radical center, followed by cyclization into the aromatic ring. This proposed mechanism provides an alternative to the commonly accepted Mayo initiation mechanism.

We report a study on the presence of the disaccharide trehalose in three desiccation tolerant tardigrades. This sugar has long been suggested to play a protective role in desiccation tolerant animals. Trehalose was found in all species, with increased levels in dehydrated specimens of Macrobiotus islandicus, and possibly also in Macrobiotus krynauwi, both belonging to the family Macrobiotidae. In the third species, Milnesium tardigradum, very low amounts of trehalose were found, with no increase in the dehydrated state. This species has previously been reported to lack trehalose. Induction of trehalose has been reported only for species in the family Macrobiotidae, where also the highest levels have been found. Although the role of trehalose in the desiccation tolerance of tardigrades remains unclear, the diverging patterns in response to desiccation are interesting. Further studies of higher tardigrade taxa are needed in order to understand the evolutionary history of trehalose in these invertebrates.