Reactions of disubstituted alkanes with a nickel(I) macrocycle
The reactions of disubstituted alkanes, X(CH/sub 2/)/sub n/Y (X, Y = Cl, Br, I, OH, OTs), with the cationic macrocyclic ion (1R,4S,8R,11S)-(1,4,8,11S)-(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)nickel(I), abbreviated Ni(tmc)/sup +/, are characterized by kinetic accelerations compared to the rates for the monohalides, most noticeably for the smaller molecules, n = 2,3. No transient organonickel species is detected for any vicinal disubstituted alkane, and the alkene is formed quantitatively. This is attributed to a reductive elimination reaction between Ni(tmc)/sup +/ and the radical /center dot/CH/sub 2/CH/sub 2/OH, known to result from the very rapid unimolecular solvolysis of the initially formed /center dot/CH/sub 2/CH/sub 2/Y. Although Br(CH/sub 2/)/sub 3/OH yields 1-propanol from the hydrolysis of the observed species (tmc)Ni(CH/sub 2/)/sub 3/OH/sup +/, 1,3-disubstituted propanes (X, Y = Br, Cl, OTs) form cyclopropane exclusively. A rapid unimolecular reaction of (tmc)Ni(CH/sub 2/)/sub 3/Y/sup +/ appears responsible. The 1,4-disubstituted alkanes yield (tmc)Ni(CH/sub 2/)/sub 4/Y/sup +/ deficient Ni(tmc)/sup +/, but ethylene is formed rapidly and quantitatively in the presence of even a catalytic concentration of Ni(tmc)/sup +/ (with Y = Br, I and to some extent Y = Cl). Similarly, (tmc)NiCH(CH/sub 3/)(CH/sub 2/)/sub 3/Y/sup +/ forms a 1:1 mixture of ethylene and propene (Y = Br, I) when Ni(tmc)/sup +/ is present and otherwise hydrolyzes to 1-Y pentane. Alkene formation from 1,4-disubstituted alkanes is attributed to the reaction of (tmc)Ni(CH/sub 2/)/sub 4/Y/sup +/ with Ni(tmc)/sup +/, producing a species (tmc)Ni(CH/sub 2/)/sub 4//sup /center dot/+/ that yields ethylene and regenerates Ni(tmc)/sup +/. 36 refs., 3 tabs.
- Research Organization:
- Iowa State Univ., Ames (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5975657
- Journal Information:
- Inorg. Chem.; (United States), Vol. 27:23
- Country of Publication:
- United States
- Language:
- English
Similar Records
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)]
Free-radical pathways to alkyl complexes of a nickel tetraaza macrocycle
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKANES
CHEMICAL REACTIONS
NICKEL COMPOUNDS
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC IODINE COMPOUNDS
EXPERIMENTAL DATA
DATA
HYDROCARBONS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties