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Title: Mechanistic investigation of carbon-carbon bond formation in the reduction of alkyl halides by organonickel complexes in aqueous solution. [R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C /sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/; X = Cl, Br, I) RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)]

Abstract

The macrocyclic alkylnickel(II) complexes, RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), react with alkyl halides R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C/sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/) in alkaline aqueous solutions, yielding combination and disproportionation products of R and R'. The reactivity of R'X increases in the order methyl < primary < secondary and Cl < Br < I. In the case R = R' = C/sub 2/H/sub 5/, the product distribution compares with that determined independently for ethyl radicals in aqueous solution. The proposed one-electron reduction of alkyl halide by the alkylnickel complexes in the rate-determining step produces an organonickel(III) complex and the alkyl halide radical anion. Both products rapidly eliminate ethyl radicals whose self-reactions yield the final products. Alkyl halide/alkyl radical exchange reactions effectively compete with radical self-reactions. The rate constant for the reaction C/sub 2/H/sub 5/ + 2-C/sub 3/H/sub 7/I ..-->.. 2-C/sub 3/H/sub 7/ + C/sub 2/H/sub 5/I in aqueous solution was determined by competition with V(H/sub 2/O)/sub 6//sup 2 +/. The value k/sub 2-PrI/ approx. 6 x 10/sup 5/ M/sup -1/ s/sup -1/ is significantly higher than in aprotic solvents.more » 50 references, 2 figures, 3 tables.« less

Authors:
;
Publication Date:
Research Org.:
Iowa State Univ., Ames
OSTI Identifier:
5826953
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Am. Chem. Soc.; (United States); Journal Volume: 108:4
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; NICKEL COMPLEXES; CATALYTIC EFFECTS; ORGANIC BROMINE COMPOUNDS; REDUCTION; ORGANIC CHLORINE COMPOUNDS; ORGANIC IODINE COMPOUNDS; ORGANOMETALLIC COMPOUNDS; AQUEOUS SOLUTIONS; BINDING ENERGY; CATALYSIS; CHEMICAL BONDS; EXPERIMENTAL DATA; CHEMICAL REACTIONS; COMPLEXES; DATA; DISPERSIONS; ENERGY; INFORMATION; MIXTURES; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; SOLUTIONS; TRANSITION ELEMENT COMPLEXES; 400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)

Citation Formats

Bakac, A., and Espenson, J.H.. Mechanistic investigation of carbon-carbon bond formation in the reduction of alkyl halides by organonickel complexes in aqueous solution. [R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C /sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/; X = Cl, Br, I) RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)]. United States: N. p., 1986. Web. doi:10.1021/ja00264a024.
Bakac, A., & Espenson, J.H.. Mechanistic investigation of carbon-carbon bond formation in the reduction of alkyl halides by organonickel complexes in aqueous solution. [R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C /sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/; X = Cl, Br, I) RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)]. United States. doi:10.1021/ja00264a024.
Bakac, A., and Espenson, J.H.. Wed . "Mechanistic investigation of carbon-carbon bond formation in the reduction of alkyl halides by organonickel complexes in aqueous solution. [R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C /sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/; X = Cl, Br, I) RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)]". United States. doi:10.1021/ja00264a024.
@article{osti_5826953,
title = {Mechanistic investigation of carbon-carbon bond formation in the reduction of alkyl halides by organonickel complexes in aqueous solution. [R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C /sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/; X = Cl, Br, I) RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)]},
author = {Bakac, A. and Espenson, J.H.},
abstractNote = {The macrocyclic alkylnickel(II) complexes, RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), react with alkyl halides R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C/sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/) in alkaline aqueous solutions, yielding combination and disproportionation products of R and R'. The reactivity of R'X increases in the order methyl < primary < secondary and Cl < Br < I. In the case R = R' = C/sub 2/H/sub 5/, the product distribution compares with that determined independently for ethyl radicals in aqueous solution. The proposed one-electron reduction of alkyl halide by the alkylnickel complexes in the rate-determining step produces an organonickel(III) complex and the alkyl halide radical anion. Both products rapidly eliminate ethyl radicals whose self-reactions yield the final products. Alkyl halide/alkyl radical exchange reactions effectively compete with radical self-reactions. The rate constant for the reaction C/sub 2/H/sub 5/ + 2-C/sub 3/H/sub 7/I ..-->.. 2-C/sub 3/H/sub 7/ + C/sub 2/H/sub 5/I in aqueous solution was determined by competition with V(H/sub 2/O)/sub 6//sup 2 +/. The value k/sub 2-PrI/ approx. 6 x 10/sup 5/ M/sup -1/ s/sup -1/ is significantly higher than in aprotic solvents. 50 references, 2 figures, 3 tables.},
doi = {10.1021/ja00264a024},
journal = {J. Am. Chem. Soc.; (United States)},
number = ,
volume = 108:4,
place = {United States},
year = {Wed Feb 19 00:00:00 EST 1986},
month = {Wed Feb 19 00:00:00 EST 1986}
}