Trend‐Analysis of Solid‐State Structures: Low‐Energy Conformational ‘Reactions’ Involving Directed and Coupled Movements in Half‐Sandwich Compounds [CpFe(CO){C(=O)R}PPh(3)]

Trends in solid‐state structures were used to identify preferred intramolecular movements in half‐sandwich compounds [CpFe(CO){C(=O)R}PPh(3)]. Three weak interactions were analyzed: 1) the CH/π donor–acceptor interaction of phenyl rings in the PPh(3) ligand, 2) the Ph(PPh3) face‐on Cp stabilization, and 3) the hydrogen bond between the oxygen atom of the acyl group and an ortho‐C−H bond of one of the PPh(3) phenyl rings. Clockwise and counter‐clockwise rotations established directed and coupled movements of the PPh(3) ligand, the acyl group, and the phenyl rings within the PPh(3) ligand.