Thermal properties and reactions towards nucleophiles of an iron complex displaying an acetyl and a pyruvoyl ligands

Phosphine Addition to Pyruvoyl Ligands of Iron Complexes: Formation of Zwitterionic Metallalactones

“…The presence of a five-membered metallacycle in the complex infers the observation of a small bite angle: C(6)−Fe(1)−C(8) = 82.7(4)°. This size falls within the range of the values measured for similar angles of homologous iron metallacycles; ,− , it is smaller than the angles measured between two nonchelating organic ligands (for example a value of 88.5(2)° is reported for cis -(CO) 4 Fe(CO 2 C 2 H 5 ) 2 ). It is worth noting that C(2)−Fe(1)−C(3), the opposite angle on the metal center, displays a higher value than expected (96.4(3)°).…”

“…This isomerization could result, as reported for ruthenium alkoxycarbonyl complexes, from a hopping of the alkoxy group of the alkoxycarbonyl ligand from one terminal carbonyl to another CH 3 ), respectively obtained as a single isomer, which display their diethylmalonyl groups and methoxycarbonyl or acetyl ligands in a trans position with respect to the medium plane of the metallacyle, the alkoxycarbonyl ligand and the phosphonium group of 2b(1) are located in cis positions relative to the same plane.…”

“…An analogous observation has been made for a reaction between a hydride and a phenylglyoxyl manganese complex . Successful use of the same process in the reaction of the related acetyl complex cis -(CO) 4 Fe[C(O)C(O)CH 3 ][C(O)CH 3 ] with the same nucleophiles confirms that the presence of an alkoxycarbonyl ligand is not required for the formation of metallalactones . As mentioned above, nucleophiles displaying mobile protons, NuH, afford neutral bisubstituted metallalactones (CO) 4 Fe[C(O)C(CH 3 )(Nu)OC(O)], while anionic nucleophiles, Nu − , give rise to trifunctionalized anionic metallalactones fac -{(CO) 3 Fe[C(O)C(CH 3 )(Nu)OC(O)](CO 2 CH 3 )} − .…”