REACTIONS OF METAL CARBONYL DERIVATIVES .I. MONOSUBSTITUTED DERIVATIVES OF TETRACARBONYLDI-PI-CYCLOPENTADIENYLDIIRON AND THEIR IODINATION REACTIONS

Tetracarbonyldi-π-cyclopentadienyldiiron reacts with the ligands L = P(C2H5)3, P(n-C3H7)3, P(n-C4H9)3, P(C6H5)2C2H5, P(OCH3)3, P(OC2H5)3, P(O-i-C3H7)3, P(O-n-C4H5)3, and P(OC6H5)3 in refluxing benzene to afford the monosubstituted complexes (π-C5H6)2Fe2(CO)3L. On the basis of infrared spectroscopic evidence it is shown that the compounds (π-C5H5)2 Fe2(CO)3L [L = P(OCH3)3, P(OC2H9)3, P(O-i-C3H7)3, P(O-n-C4H9)3, P(OC6H5)3, and P(C6H5)3] occur as a mixture of isomers in solution whereas the derivatives (π-C6H5)2Fe2(CO)3L [L = P(C2H5)3, P(n-C3H7)3, P(n-C4H9)3 and P(C6H3)2C2H5] are present in solution as a single isomer. Possible structures for these isomers are discussed. The reaction of (π-C5H5)2Fe2(CO)3L [L = P(C2H5)3, P(O-i-C3H7)3, and P(OC6H3)3] with iodine involves asymmetric cleavage of the parent compounds to yield the ionic derivatives [π-C5H5Fe(CO)2 L] I as well as symmetric cleavage to give the complexes π-C6H5Fe(CO)LI and π-C6H5- Fe(CO)2I. © 1969, American Chemical Society. All rights reserved.