Kinetics of acetyl radical formation from methyl radicals and carbon monoxide and crystal structures of two acetylcobalt complexes
- Ames Lab., IA (United States)
Methyl radicals react with macrocyclic cobalt complexes (H[sub 2]O)[sub 2]LCo[sup 2+] (L[sup 1] = 1,4,8,11-tetraazacyclotetradecane, L[sup 2] = C-meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) in the presence of CO in acidic aqueous solution. The reaction yields a mixture of methyl and acetyl complexes as a result of the competition between CO and (H[sub 2]O)[sub 2]CoL[sup 2+] for CH[sub 3][center dot]. Kinetic competition experiments yielded the rate constant for the capture of CH[sub 3][center dot] by CO, k[sub CO] = (2.0 [+-] 0.3) [times] 10[sup 6] M[sup [minus]1] s[sup [minus]1]. The acetyl complex of CoL[sup 1] crystallizes with either H[sub 2]O or ClO[sub 4][sup [minus]] coordinated trans to the acetyl group. Both the red [(ClO[sub 4])L[sup 1]CoC(O)CH[sub 3]](ClO[sub 4]) (1) and the yellow [(H[sub 2]O)L[sup 1]-CoC(O)CH[sub 3]](ClO[sub 4])[sub 2][center dot]H[sub 2]O (2) crystallize in the centric space group P2[sub 1]/c with four molecules in a unit cell of dimensions a = 10.539 (1) [angstrom], b = 12.548 (2) [angstrom], c = 14.915 (2) [angstrom], and [beta] = 93.74 (3)[degree] for 1 and a = 12.588 (3) [angstrom], b = 8.821 (3) [angstrom], c = 19.398 (5) [angstrom], and [beta] = 96.34 (2)[degree] for 2. The data refined to final values of the unweighted R factors of 0.037 (1) and 0.054 (2).
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6827129
- Journal Information:
- Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:24; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACETYL RADICALS
ACYL RADICALS
ALKYL RADICALS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COBALT COMPLEXES
COHERENT SCATTERING
COMPLEXES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
EXPERIMENTAL DATA
INFORMATION
KINETICS
LATTICE PARAMETERS
METHYL RADICALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RADICALS
REACTION KINETICS
SCATTERING
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION