An iron(II) complex featuring κ(3) and labile κ(2)-bound PNP pincer ligands - striking differences between CH2 and NH spacers.

Treatment of anhydrous FeCl2 with 2 equiv. of the pincer ligand PNP-Ph afforded the diamagnetic cationic octahedral complex [Fe(κ(3)-P,N,P-PNP)(κ(2)-P,N-PNP)Cl](+) featuring a κ(2)-P,N-bound PNP ligand. Preliminary reactivity studies revealed that the κ(2)-P,N-bound PNP ligand is labile reacting with CO to afford trans-[Fe(PNP-Ph)(CO)2Cl](+).