Summary: The synthesis of C1‐symmetric zirconocene complexes bearing the 2,5‐dimethyl‐7H‐cyclopenta[1,2‐b:4,3‐b′]dithiophene ligand (S2‐3) linked to substituted cyclopentadienes is described. Different syntheses of S2‐3, the common intermediate for the preparation of these complexes, are discussed. Many of these complexes have been found to be highly active in propylene polymerization, to require very low amounts of methylalumoxane to be activated, and to produce poly(propylene)s of low isotacticity and melting points. 13C NMR analysis shows that the poly(propylene)s are fully regioregular and that the stereoerrors are randomly distributed, as shown by the enantiomorphic‐site triad test E ≈ 1. The experimental pentad distribution was fitted using a two‐site model with different probability parameters for each site. The probability of chain back‐skip was also taken into account. The molecular weight and crystallinity of the poly(propylene)s are dependent upon the type of substituents on the cyclopentadienyl ring, and the correlation between mmmm content and melting point of the PP confirms the random distribution of stereoerrors.Correlation between % mmmm pentad and melting point.magnified imageCorrelation between % mmmm pentad and melting point.

The identification of a variety of alkyl naphthalene carboxylic and alkanoic and alkyl tetralin carboxylic and alkanoic acids, plus identifications of a range of alkyl indane acids, provides further evidence for 'signature' metabolites of biodegradation of aromatic petroleum hydrocarbons. Identifications such as these now offer the prospect of better differentiation of metabolites of bacterial processes (e.g. aerobic, methanogenic, sulphate-reducing) in polar petroleum fractions.

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