Donor-sigma-acceptor-lipid molecules were prepared by using perylenetetracarboxylic diimide as the acceptor, starting from perylenetetracarboxylic dianhydride. One imide nitrogen was attached to a "swallowtail" lipid (a long alkyl tail connected at midchain), which imparts enough solubility to make the system tractable and provides a lipophilic region suitable for promoting Langmuir-Blodgett monolayer formation. The other imide link was to a donor group (pyrene, ferrocene, tetramethylphenylenediamine, phenyl) through a short alkyl sigma bridge. Features of the 1H and 13C NMR spectra of swallowtailed perylenediimides are interpreted as resulting from restricted rotation about the imide C-N bond; the 13C NMR spectra and stereochemistry of these molecules are contrasted with the case of the related bis-(2,5-di-tert-butylphenyl)perylenetetracarboxylic diimide.

A major component of carbon vapor is C%. The chemical properties of this substance were studied at -196°in additions to olefins, the products being bisethanoallenes.Relative rates show C3 to be a nonselective dicarbene for olefin additions and yet it does not show insertion properties. In a paraffin hydrocarbon matrix at -196°, C3 is stable. This variety of C3 adds stereospecifically to cis-and trans-2-butenes, confirming the conclusion from spectroscopic analysis of the Swings bands that the ground state is singlet. Nonstereospecificity is observed with simultaneous deposition at -196°o f C3 and the 2-butenes, indicative of a hitherto unobserved triplet state C3; limits of 10_1 to 10~5 seer1 have been placed on the half-life for decay of this triplet state to a singlet state.

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