Syntheses, X-ray crystal structures, and ligand substitution kinetics of the carbon-bonded chromium(III) complexes trans-(CrR(acac)/sub 2/(L)) (R = CH/sub 2/Cl, CHCl/sub 2/; L = H/sub 2/O, CH/sub 3/OH, pyridine)

Journal Article · Wed Jul 29 04:00:00 EDT 1987 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00262a039· OSTI ID:5522724

Ogino, H; Shoji, M; Abe, Y; Shimura, M; Shimoi, M

The alkylchromium(III) complexes trans-(CrR(acac)/sub 2/(H/sub 2/O)) (a) (R = CHCl/sub 2/, CH/sub 2/Cl; Hacac = 2,4-pentanedione) were prepared by the reaction of (CrR(H/sub 2/O)/sub 5/)/sup 2 +/ with Hacac and triethylamine. Synthetic methods reported previously for (CrR(H/sub 2/O)/sub 5/)/sup 2 +/ (R = CHCl/sub 2/, CH/sub 2/Cl) were improved to give approximately quantitative yields. The complexes trans-(CrR(acac)/sub 2/L) (L = CH/sub 3/OH, pyridine) were derived by replacing a coordinated water molecule in a with L. The X-ray crystal structure analyses of trans-(CrR(acac)/sub 2/(py)) (R = CHCl/sub 2/, CH/sub 2/Cl) have been performed. The carbon-bonded ligands CHCl/sub 2/ and CH/sub 2/Cl lengthen specifically the Cr-N bond trans to the Cr-C bond in trans-(Cr(CHCl/sub 2/)(acac)/sub 2/(py)) (b; Cr-N = 2.154 (7) A) as well as in trans-(Cr-(CH/sub 2/Cl)(acac)/sub 2/(py)) (c; Cr-N = 2.201(4) A). The elongation of the Cr-N bonds in b and c is reflected in substantial labilization of the ligand substitution reactions at the position trans to R: trans-(CrR(acac)/sub 2/(CH/sub 3/OH)) + L reversible trans-(CrR(acac)/sub 2/L) + CH/sub 3/OH. The rate constants (M/sup -1/ s/sup -1/) at 25 /sup 0/C in methanol for the formation of trans-(CrR(acac)/sub 2/L) are 85 +/- 2 (R = CHCl/sub 2/, L = py), 98 +/- 1 (R = CHCl/sub 2/, L = 4-methylpyridine), 57 +/- 1 (R = CHCl/sub 2/, L = isonicotinamide), and (1.2 +/- 0.5) x 10/sup 3/ (R = CH/sub 2/Cl, L = py), and the rate constants (s/sup -1/) for the backward reaction at 25 /sup 0/C are 15 +/- 1 (R = CHCl/sub 2/, L = py), 11 +/- 1 (R = CHCl/sub 2/, L = 4-methylpyridine), 33 +/- 1 (R = CHCl/sub 2/, L = isonicotinamide), and (5 +/- 2) x 10/sup 2/ (R = CH/sub 2/Cl, L = py).

• Research Organization: Tohoku Univ., Sendai, Japan
• OSTI ID: 5522724
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 26:15; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
AZINES
CHEMICAL BONDS
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COHERENT SCATTERING
COMPLEXES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
KETONES
KINETICS
LIGANDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
REACTION KINETICS
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION