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Metal complexes of meso-arylporphyrins (Cr(III), Fe(III), and Zn(II)) were evaluated in the coupling reaction of cyclohexene oxide (CHO) with CO 2 in compressed medium, where the Cr complexes were demonstrated to be the most active systems, leading predominantly to copolymerisation products. It is noteworthy that no addition of solvent was required. To improve the catalytic activity, and to simultaneously increase the solubility in compressed CO 2 , a new fluorinated catalyst, tetrakis(4-trifluoromethylphenyl)porphyrinatochromium(III) chloride (CrCl-pCF 3 TPP), was applied to this reaction. The alternating copolymerisation of CHO with CO 2 , using the Cr(III) fluorinated porphyrin catalyst, required the use of a co-catalyst, bis(triphenylphosphine)iminium chloride (PPNCl), with the best yields of copolymers being obtained at 80 • C, and CO 2 pressures in the range of 50-110 bar, over a period of 24 h, with a low catalyst/substrate molar ratio (0.07%). The polycarbonate's structure was analysed by 1 H NMR, 13 C NMR, and MALDI-TOF spectroscopy, which demonstrated high carbonate incorporations (98-99%). Gel permeation chromatography revealed number-average molecular weights (M n ) in the range of 4800-12,800 and narrow molecular weight distributions (M w /M n ≤ 1.63).

(Received 7 May 1996; accepted 25 June 1996) This work was funded by the Deutsche Forschungsgemeinschaft. SAAS thanks the Alexander von HumboldtStiftung for a postdoctoral fellowship. PL thanks the European Community for a postdoctoral grant (BBW 94.0162 CHBG CT 940731). AbstractThe title compound, C23H26N204, consists of a partially hydrogenated acridine moiety with one 2-nitrophenyl substituent on the central ring. The acridine nucleus suf-

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