Rotameric transformations in the photochemistry of (η5-C5H5)Ru(CO)(η3-C3H5) and (η3-C3H4R)Fe(CO)2NO, where R = H or Me

Photolysis of exo-(η5-C5H5)Ru(CO)(η3–C3H5) in frozen Nujol matrices results in formation of the endo isomer as well as a band assigned to the η1-allyl species that appears to be the likely intermediate in these transformations. The photochemistry of (η3-C3H4R)Fe(CO)2NO, where R = H or Me, is dominated by the rotational isomerism of the allyl ligand. In the case of the 2-methylallyl ligand bands are observed upon visible light photolysis that may be assigned to the isonitrosyl linkage isomer. The behavior of these “open” allyl compounds is in contrast to that of (η3-t-Bu3C3)Fe(CO)2NO where both NO linkage isomerism and CO-loss is observed.