The helical sense of the peptidic parts of a cyclodimeric zinc porphyrin host with helical oligopeptide units (1) determines whether a right‐ or left‐handed oligopeptide guest (2) is selectively bound (see picture). In contrast, enantiomers of nonhelical peptidic guests containing a point chirality are hardly discriminated.

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The new radical scavenger 12T061C (C 20 H 22 O 7 ) has been identified from a culture of Streptomyces species. Spectroscopic elucidation showed that this compound is a new Julichrome family compound. 12T061C shows a potent radical-scavenging activity with an ED 50 of 18 μm that is similar to those of the known antioxidant compounds α-tocopherol (ED 50 16 μm) and quercetin (ED 50 3 μm).

The preparation of lustrous conducting polyacetylene films by the polymerization of acetylene with vinyltitanium species as initiators was studied. Organotitanium species were generated by the alkylation of titanium vinylcarbene complexes with tert‐butyl chloride. Solid‐state 13C NMR and IR analyses of the obtained polyacetylene indicated that polyacetylene with a trans configuration was produced. The use of titanocene(II) species Cp2Ti[P(OEt)3]2 and titanium vinylcarbene complexes for the preparation of polyacetylene films was also studied. The morphology of the films and the mechanisms of polymerization are discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2663–2669, 2002

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