Synthesis of Iron and Cobalt Complexes of a Ferrocene-Linked Diphosphinoamide Ligand and Characterization of a Weak Iron–Cobalt Interaction

A ferrocene-based bis­(phosphinoamine) fc­(NHPiPr2)2 has been deprotonated and used in salt metathesis reactions to form dimeric complexes ([fc­(NPiPr2)2]­M)2 (M = Fe, Co). A novel coordination environment for Co­(II) is observed including a weak but significant Fe–Co interaction, which was characterized using X-ray crystallography, Mössbauer spectroscopy, and VT-magnetometry. Density functional theory (DFT) calculations including natural bond order analysis provides further support for the interaction and suggests a combination of Fe → Co and Co → Fe interactions.