Bulky, polydentate phosphines are applied commonly for transition metal-catalyzed cross-coupling reactions (Heck arylation, Suzuki coupling etc.) [1]. The catalytic efficiency is the highest for ligands with such 'rigid' conformation which provides several (phosphorus) coordinative sites to be present nearby the metal core during the coupling reaction (see e.g. [Pd(II)Br2-Fc(P)4tBu] in the figure, adapted from [1]). However, when the system is investigated on 'NMR timescale', the hindered structural motions might be revealed. Our goal is to identify and quantitatively characterize dynamic processes for phosphine ligands and their transition metal complexes, and thus to demonstrate the structural background of the catalytic behaviour.
