High-resolution 2H MAS NMR applied to deuterium analogs of hydrido eta2-dihydrogen complexes.
(2)H solid-state, variable temperature magic angle spinning (MAS) NMR spectra of precipitated samples of the deutero dideuterium complexes Ru(D)(2)(eta(2)-D(2))(2)(PCy(3))(2) and RuD(eta(2)-D(2))I(PCy(3))(2) [Cy=cyclohexyl] are presented. They show that even at moderate MAS speed, high resolution is achieved at 7 and 14T allowing (2)H chemical shifts and quadrupole couplings to be obtained and assigned to different solid and gaseous (2)H species. These two parameters allow identifying chemically different hydrogen species in the material. The analysis of these parameters in this study reveals the presence of three different species in the sample, namely the complexes RuD(eta(2)-D(2))I(PCy(3))(2) and RuD(eta(2)-D(2))(2)I(PCy(3))(2), and highly mobile HD/D(2). These assignments are supported by (2)H T(1) relaxation times and (31)P MAS NMR spectra. Moreover, variable temperature MAS NMR spectra reveal temperature-dependent line-shape changes, which are clear indications of intramolecular hydrogen exchange of the deutero and the dideuterium ligands and which give an estimate for the activation energy of this process.
Freie Universität Berlin, Institut für Chemie und Biochemie, Takustr. 3, 14195 Berlin, Germany. sven.macholl@ge.com
Sven
S
Macholl
Jochen
J
Matthes
Hans-Heinrich
HH
Limbach
Sylviane
S
Sabo-Etienne
Bruno
B
Chaudret
Gerd
G
Buntkowsky
D003903:Deuterium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D017975:Ruthenium Compounds / Q000737:chemistry*; D013696:Temperature
D017975:Ruthenium Compounds; D003903:Deuterium