Photochemical cis-trans isomerization of β-styrylferrocene

<p>The effect of metal atoms on photochemical transformations has been investigated by studies of the cis-trans isomerization of β-styrylferrocene.</p> <p>The photostationary state lies entirely on the side of the trans isomer in the cases of direct irradiation at 3130 Å or at 3660 Å. The quantum yield at 3130 Å is 0.00650 and does not vary with concentration. In the presence of benzophenon as sensitizer the quantum yield is 0.00540. On the other hand, the quantum yield for direct irradiation at 3660 Å decreases with increasing concentration of cis β- styrylferrocene varying from 0.00365 to 0.00198.</p> <p>These results lead to the suggestion that the isomerization takes place from a triplet state of β-styrylferrocene which probably has higher energy than the lowest triplet; reaction from the third triplet seems most likely.</p>