Reversible coordination of molecular nitrogen to polymeric benzenecarbonylchromium complexes

Polymeric benzenetricarbonylchromium complexes were synthesized by radical copolymerization of benzyl acrylatetricarbonylchromium with styrene and by reaction of (dimethylaminobenzene)tricarbonylchromium with poly(styrene-co-acrylic acid). The polymeric chromium complexes give transparent films and on UV irradiation under nitrogen lead to dinitrogen complexes of the corresponding polymeric dicarbonylchromium. The reversible coordination of dinitrogen was confirmed by IR and visible absorption spectroscopy. A predominant feature of the polymeric dinitrogen complexes is their extraordinarily high stability in air compared with the corresponding low molecular analogs. The effect of polymer matrices on dinitrogen coordination is discussed.