Oxidative and electrophilic pathways in the reactions of pentaaquo(organo)chromium(2+) ions with nitrous acid
The reactions of HONO with (H/sub 2/O)/sub 5/CrR/sup 2 +/ complexes occur with a 1:1 stoichiometry at rates ranging from 0.12 (R = CH/sub 2/Br) to 1010 M/sup -2/ s/sup -1/ (R = rho-CH/sub 2/C/sub 6/H/sub 4/CH/sub 3/). The chromium product is Cr(H/sub 2/O)/sub 6//sup 3 +/ for R = alkyl, haloalkyl, and aralkyl but the kinetically stable nitrosyl complex (H/sub 2/O)/sub 5/CrNO/sup 2 +/ for R = ..cap alpha..-hydroxy- and ..cap alpha..-alkoxyalkyl. All of the reactions are believed to proceed by a bimolecular reaction between the nitrosyl cation NO/sup +/ and CrR/sup 2 +/. In the case of the aralkyl complexes, the data are consistent with an electrophilic process; correlations with data in the literature support the assignment of an S/sub E/2 mechanisms. The other reactions are best interpreted in terms of electron transfer to form CrR/sup 3 +/. The fate of the latter depends on the nature of the group R. Intramolecular electron transfer for R = CH/sub 2/OH, CH/sub 2/OCH/sub 3/, and CH(C-H/sub 3/)OC/sub 2/H/sub 5/ results in Cr/sup 2 +/, which is scavenged by NO to give CrNO/sup 2 +/. The rate constant for the reaction between Cr/sup 2 +/ and NO has been independently evaluated as 2.2 x 10/sup 6/ M/sup -1/ s/sup -1/ by competition methods. All the other CrR/sup 3 +/ complexes decompose by homolysis. The free radical so formed reacts with NO to yield RNO. 57 references, 7 figures, 3 tables.
- Research Organization:
- Iowa State Univ., Ames
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6952925
- Journal Information:
- Inorg. Chem.; (United States), Vol. 25:19
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKANES
CHEMICAL PREPARATION
ELECTRON TRANSFER
CHROMIUM COMPLEXES
NITROUS ACID
ORGANIC OXYGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
WATER
EXPERIMENTAL DATA
REACTION KINETICS
COMPLEXES
DATA
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties