Triaqua(benzene)ruthenium(II) and triaqua(benzene)osmium(II): Synthesis, molecular structure, and water-exchange kinetics

Journal Article · Wed Apr 20 04:00:00 EDT 1988 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00281a009· OSTI ID:5614903

Stebler-Roethlisberger, M; Hummel, W; Pittet, P A; Buergi, H; Ludi, A; Merbach, A E

Solid salts of M(/eta/-C/sub 6/H/sub 6/)(H/sub 2/O)/sub 3//sup 2+/ (M = Ru, Os) are obtained by reacting (MCl/sub 2/(/eta/-C/sub 6/H/sub 6/))/sub 2/ with Ag/sup +/ in aqueous solution or by the reaction of Ru(H/sub 2/O)/sub 6//sup 2+/ with cyclohexadiene in ethanol. (Ru(/eta/-C/sub 6/H/sub 6/)(H/sub 2/O)/sub 3/)SO/sub 4/ crystallizes in the orthorhombic space group Pbca with a = 12.892 (2) /angstrom/, b = 12.441 (1) /angstrom/, and c = 12.183 (2) /angstrom/ (T = 125 K), and Z = 8. The structure was refined to 1.9% for 2168 reflections with F/sub 0/ > 3/sigma/(F/sub 0/). The relative arrangement of the benzene ring and the three water molecules is approximately staggered, the torsional angle being 19.2 (4)/degree/. After correction for thermal motion, average distances are Ru-C = 2.164 (4), C-C = 1.419 (5), and Ru-O = 2.117 (11) /angstrom/. The Ru-center of the benzene plane distance is 1.631 /angstrom. Structural results obtained at 295 K agree with those at 125 K. Water-exchange rates at variable temperature and pressure were determined by line width measurements of 17/O NMR spectra at 4.7 T. For Ru(/eta/-C/sub 6/H/sub 6/)(H/sub 2/O)/sub 3//sup 2+/ and Os(/eta/-C/sub 6/H/sub 6)(H2/O)/sub 3//sup 2+/ the following results are obtained: k(298 K), 11.5 /plus minus/ 3.1 and 11.8 /plus minus/ 2.0 s/sup /minus/1/; /Delta/H*, 75.9 /plus minus/ 3.8 and 65.5 /plus minus/ 2.2 kJ mol/sup /minus/1/; /Delta/S*, +29.9 /plus minus/ 10.6 and /minus/4.8 /plus minus/ 6.1 J K/sup /minus/1/ mol/sup /minus/1/; /Delta/V*, +1.5 /plus minus/ 0.4 and +2.9 /plus minus/ 0.6 cm/sup 3/ mol/sup /minus/1/. The reaction proceeds via an interchange mechanism (I) where the bond-breaking contribution has only a slightly larger weight than the bond-making one. The kinetic behavior indicates a strong trans-labilizing influence of the aromatic ligand. 30 refs., 3 figs., 7 tabs.

• Research Organization: Universitaet Bern (Switzerland)
• OSTI ID: 5614903
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 27:8; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
BENZENE
COMPLEXES
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
OSMIUM COMPLEXES
OXYGEN 17
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
RUTHENIUM COMPLEXES
SPECTRA
STABLE ISOTOPES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
WATER