Di‐μ‐hydrido‐bis[1,3‐propanbis(dicyclohexylphosphin)]dinickel(NiNi) — Der Bindungszustand in einem Dreizentren‐Wasserstoff‐überbrückten NiNi‐System

The crystal structure of the title compound, [(C 6 H 11 ) 2 PCH 2 CH 2 CH 2 P(C 6 H 11 ) 2 NiH] 2 ( 1 ), has been determined from 4051 reflections and refined to a final R ‐value of 0.044. The positions of the hydrogen atoms (bridging and non‐bridging) have been determined from a difference Fourier synthesis. The molecular structure of the diamagnetic compound consists of subunits doubly‐bridged by hydrogen atoms. The NiNi and average NiH distances are 2.441 and 1.6 Å, respectively. In the solid state the two planes of the P 2 Ni units form a dihedral angle of 63.3°. Theoretical considerations predict a square‐planar structure for the idealized molecule with a soft potential energy surface for a twisting motion towards the observed geometry. The observed twist is the result of severe intramolecular repulsions between the cyclohexyl groups of the two P 2 Ni units.