The conformational analysis of phosphine ligands in organometallic complexes. Part 1. Triphenylphosphine coordinated to an achiral metal centre 1

Conformation analysis of triphenylphosphine in trans and cis triphenylphosphine-substituted Fischer carbene complexes

“…In free PPh 3 correlate reasonably well with the calculated value of -50 ± 10°, using molecular modelling calculations [37]. The observed distortion of molecular symmetry in the crystal state is considered consistent with packing effects [37,38].…”

“…However, the preferred orientation of complex-bound PPh 3 in the solid state generally appears to be the same, as illustrated in Figure 6. The orientation of PPh 3 relative to the ligands of the complex it is attached to, depends if the complex is tetrahedral, trigonal bipyramidal [37], square planar…”

“…In solution, fast inversion between the two helicities occur [36], the barrier to inversion is low [37], and the two conformations are equi-energetic. In free PPh 3 correlate reasonably well with the calculated value of -50 ± 10°, using molecular modelling calculations [37].…”

Stereochemical Nonrigidity of Organometallic Complexes

“…Perhaps the most convenient technique is noting the retention of spin coupling with a ligand when a dynamic process is observed in the absence of an added ligand. This is most commonly used with 31 P coupling in phosphines or with metals having observable spin coupling, such as 195 Pt, 103 Rh, or 183 W. Coupling of other ligands to 31 P is averaged since when a ligand with a 31 P with spin +1/2 dissociates a 31 P with spin −1/2 can return and this produces an average of the components of the doublet arising from coupling to 31 P. In this context, one should note that if a 31 P with spin +1/2 returns, the frequency of the resonance would not change; hence, the coupled nucleus ''would not know that anything had happened.'' Hence, if broadening of a doublet from exchange of 31 P is involved, one may need to double the rate constant obtained from equations such as equation (3), to provide a chemically meaningful exchange rate.…”

Chemical and Electrochemical Oxidation of Tris(3,5‐di‐tert‐butylphenyl)phosphine – High Z′ Crystal Structures and Conformational Effects Associated with Bulky meta Substituents

“…His group established the strong connection of experiment (originally from dynamic NMR spectroscopy) with pioneering work in computational stereochemistry . Interest in this area remains strong amongst triarylphosphines, triarylphosphine chalcogenides,, and conformations of Ar 3 P ligands in coordination complexes …”