²H Solid-State NMR of Ruthenium Complexes

Abstract

The (2)H solid-state NMR spectra of the transition metal complexes Tp*RuD(THT)(2) (1a), Tp*RuD(D(2))(THT) (1b), Tp*RuD(D(2))(2) (1c), Cp*RuD(3)(PPh(3)) (2) and RuD(2)(eta(2)-D(2))(2)(PCy(3))(2) (3) have been measured in a wide temperature range. These compounds were chosen as potential model systems for hydrogen surface species in Ru-nanoparticles. The deuterium quadrupolar coupling constants Q(cc) and asymmetry parameters were extracted by (2)H NMR line-shape analysis. The Q(cc) values of the deuterons bound to the metal vary between 13 kHz and 76 kHz. In addition all spectra show that some of the deuterium is incorporated into carbon positions exhibiting quadrupolar coupling constants in the range of 134 kHz to 192 kHz. The room temperature spectra contain an additional weak very narrow line which was assigned to deuterons exhibiting a high mobility. These deuterons are attributed to crystallographic impurity and partially to D(2) molecules which lost by the complexes. The temperature where their motion is quenched and the types of these motions depend on the chemical structure. We propose to use the values of the quadrupolar coupling constants measured in order to characterize different hydrogen species on the surface of Ru-nanoparticles.

Bifunctional Iron Complexes: Efficient Catalysts for CO and CN Reduction in Water

“…Recently, some of the authors have proposed the foundation of this work, with molecular density functional theory (DFT) calculations of quadrupole coupling constants Q cc and the asymmetry parameter η Q , (see the Supporting Information for definitions) of deuteron in ruthenium complexes6 directly comparable with the experimental data 1g. There is no doubt now that joint theoretical/experimental studies are a very powerful approach to complete the partial understanding of deuteron solid‐state NMR spectra.…”

Bis σ-Bond Dihydrogen and Borane Ruthenium Complexes: Bonding Nature, Catalytic Applications, and Reversible Hydrogen Release

“…If in solution, the hydrides and the dihydrogen ligands are in fast exchange, extensive knowledge has been gained regarding the coordination modes of the hydrogen atoms around the coordination sphere of the metal in the solid state. The most recent achievements are the solid-state NMR data for 1 40 and the neutron structure for 2. 32 With six hydrogen atoms around the ruthenium, one can expect evolution of 3 equiv of dihydrogen, but we have shown that the phosphine ligands are also a potential source of dihydrogen evolution through C-H activation.…”

Investigation of the surface chemistry of phosphine-stabilized ruthenium nanoparticles – an advanced solid-state NMR study

“…For example, the influence of amine and phosphine ligands on the size and shape control of Pd and Ru nanoparticles, [39][40][41] the influence of a diphosphine on the dynamics of CO molecules and their oxidation in comparison with the polymer PVP 42 or the coordination of NHC-carbenes on the a Institute of Physical Chemistry, Technical University Darmstadt, surface of RuNPs and their effect on the hydrogenation of styrene or other arenes were determined. 43,44 Inspired by previous experimental and theoretical solid-state NMR investigations of deuterium/hydrogen in Ru complexes and clusters, [45][46][47][48][49][50] surface investigations by 2 H solid-state NMR techniques allowed us to obtain useful information on the complex phenomena taking place on the surface of the particles. [51][52][53][54][55] Detailed overviews on these investigations are given in two recent reviews.…”