Glatz, M., Schröder-Holzhacker, C., Bichler, B., Stöger, B., Mereiter, K., Veiros, L. F., & Kirchner, K. (2016). Synthesis and characterization of cationic dicarbonyl Fe(II) PNP pincer complexes. Monatshefte Für Chemie - Chemical Monthly. https://doi.org/10.1007/s00706-016-1811-x
Monatshefte für Chemie - Chemical Monthly
In the present work, we have prepared a series of octahedral Fe(II) complexes of the type trans-[Fe(PNP)(CO)2Cl]+—PNP are tridentate pincer-type ligands based on 2,6-diaminopyridine. These complexes are formed irrespective of the size of the substituents at the phosphorus sites and whether cis-[Fe(PNP)(Cl2)(CO)] or trans-[Fe(PNP)(Cl2)(CO)] are reacted with CO in the presence of 1 equiv of silver salts. X-ray structures of representative complexes are presented. Based on simple bonding considerations the selective formation of trans-dicarbonyl Fe(II) complexes is unexpected. In fact, DFT calculations confirm that trans-dicarbonyl complexes are indeed thermodynamically disfavored over the respective cis-dicarbonyl compounds, but are favored for kinetic reasons.
Iron complexes; PNP pincer ligands; Carbon monoxide; DFT calculations