The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing P^R₂N^R′₂ ligands, which have been shown to be highly active H₂ oxidation/production catalysts. A series of [Fe(P^Ph₂N^Bn₂)₂(X)(Y)]ⁿ⁺ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(P^Ph₂N^Bn₂)₂Cl₂ reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N⋯P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(P^Ph₂N^Bn₂)₂(CH₃CN)]⁺ and trans-HFe(P^Ph₂N^Bn₂)₂Cl, resulting in short N⋯H distances. Spectroscopic and computational studies of trans-[HFe(P^Ph₂N^Bn₂)₂(CO)]⁺, trans-[HFe(P^Ph₂N^Bn₂)(P^Ph₂N^Bn₂H)(CO)]²⁺, and trans-[HFe(P^Ph₂N^Bn₂)₂(H₂)]⁺ indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H⁻ > CO > H₂ > PR₃ > Cl⁻ ∼ CH₃CN.