The barrier to rotation of dihydrogen in Cr(CO)[sub 3](PCy[sub 3])[sub 2]([eta][sup 2]-H[sub 2]), a complex with an unusually high difference in solid- and solution-state stabilities
- Los Alamos National Lab., NM (United States)
- Inst. Laue-Langevin, Grenoble (France)
The third member in the group 6 series of dihydrogen complexes, Cr(CO)[sub 3](PCy[sub 3])[sub 2]([eta][sup 2]-H[sub 2]), has been synthesized as a solid which completely dissociates H[sub 2] in solution. Inelastic neutron scattering showed the barrier to rotation of the [eta][sup 2]-H[sub 2] to be 1.3 kcal/mol, compared to 1.7 and 2.2 kcal/mol for the Mo and W analogues. [nu][sub s](M-H[sub 2]) and [nu][sub as](M-H[sub 2]) occurred at 950 and 1,540 cm[sup [minus]1], similar to that for M = W but higher than for M = Mo ([nu][sub s] = 885 cm[sup [minus]1]). These results indicate that the overall M-H[sub 2] bond strength is less for Mo than for either Cr or W, but that d[pi] [yields] [sigma]* H[sub 2]back-bonding is lowest for Cr.
- OSTI ID:
- 6915733
- Journal Information:
- Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:9; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
080000 -- Hydrogen
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
BINDING ENERGY
CHEMICAL REACTION KINETICS
CHROMIUM COMPLEXES
COHERENT SCATTERING
COMPLEXES
DIFFRACTION
DISPERSIONS
ELEMENTS
ENERGY
ENERGY LEVELS
EXCITED STATES
HYDROGEN
KINETICS
LIGANDS
MIXTURES
MOLECULAR STRUCTURE
NONMETALS
REACTION KINETICS
ROTATIONAL STATES
SCATTERING
SOLIDS
SOLUTIONS
STRUCTURE FACTORS
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION