(Co)cyclodimerization of alkynes by aluminum halides. Synthesis of pyridines from aluminum halide .sigma. complexes of cyclobutadienes and nitriles

1982 ◽  
Vol 47 (6) ◽  
pp. 989-997 ◽  
Author(s):  
H. Hogeveen ◽  
R. F. Kingma ◽  
D. M. Kok
Keyword(s):  
Sigma Complexes ◽  
Aluminum Halide ◽  
Aluminum Halides

Aluminum Nanoparticle Synthesis by Reduction of Halides with Na/K

2007 ◽  
Vol 1056 ◽  
Author(s):  
Andrew P Purdy ◽  
Joel B Miller ◽  
Rhonda M Stroud ◽  
Katherine A Pettigrew
Keyword(s):  
Nanoparticle Synthesis ◽  
Aluminum Nanoparticles ◽  
Sodium Potassium ◽  
Slight Excess ◽  
Aluminum Halide ◽  
The Stability ◽  
Aluminum Halides ◽  
Lithium Powder

ABSTRACTSolutions or mixtures of aluminum halides AlX3 (X = Cl, Br, I) or aluminum halide alkoxide (ROAlX2; R= i-Pr, X = Cl, Br) are prepared in toluene, or pentamethyldiethylenetriamine (PMDETA) and treated with a slight excess of 50:50 (wt.) sodium potassium alloy (Na/K). Upon agitation, the reaction takes place slowly. The reaction appears to be limited by the deposition of insoluble products on the surface of the Na/K since sonication in an ordinary ultrasonic cleaner is necessary to bring the reaction to completion in several hours. Aluminum nanoparticles (NPs) and Na and K halides are formed, and soluble Al compounds, are also formed in some cases. Lithium powder is used instead of Na/K to reduce Al(N(SiMe3)2)3 to Al NPs. In an effort to passivate the surface of the Al particles to oxidation or hydrolysis, various agents are added either during the reaction or afterward. The products are characterized by SEM, XRD, NMR, and TEM, and the stability to water and air is evaluated.

Interaction of heterocycles and nucleophiles. II. Sigma complexes formed from methoxide ion and Methoxy-3,5-dinitropyridines in dimethyl sulphoxide

1970 ◽  
Vol 23 (5) ◽  
pp. 957 ◽  
Author(s):  
MEC Biffin ◽  
J Miller ◽  
AG Moritz ◽  
DB Paul
Keyword(s):  
Dimethyl Sulphoxide ◽  
No Conversion ◽  
Solvation Effects ◽  
Sigma Complexes ◽  
Sigma Complex ◽  
Methoxide Ion ◽  
Rearrangement Reactions

Contrasting behaviour is observed when 2- and 4-methoxy-3,5-dinitropyridine interact with methoxide ion in dimethyl sulphoxide. The 4-methoxy compound affords both methine and acetal sigma complexes, the latter being thermodynamically more stable. The interconversion is catalysed by methanol. Labelling experiments have established that the sigma complex from the 2-methoxypyridine is formed by addition at C6; no conversion into the acetal could be effected. These observations are rationalized in terms of differential steric and solvation effects. Demethylation and rearrangement reactions of 4-methoxy-3,5-dinitropyridine are reported.

Hückel and Möbius Aromaticity in Charged Sigma Complexes

2019 ◽  
Vol 25 (31) ◽  
pp. 7457-7462 ◽  
Author(s):  
Michael Mauksch ◽  
Svetlana B. Tsogoeva
Keyword(s):  
Sigma Complexes

Complexes of Organotin Compounds with Aluminum Halides

1964 ◽  
Vol 3 (5) ◽  
pp. 385-386 ◽  
Author(s):  
W. P. Neumann ◽  
R. Schick ◽  
R. Koster
Keyword(s):  
Organotin Compounds ◽  
Aluminum Halides

ChemInform Abstract: Novel Halogenation of Thiophenes with Benzeneseleninyl Chloride and Aluminum Halide.

ChemInform ◽  
1990 ◽  
Vol 21 (51) ◽  
Author(s):  
N. KAMIGATA ◽  
T. SUZUKI ◽  
M. YOSHIDA
Keyword(s):  
Aluminum Halide
Sign in / Sign up

Export Citation Format

Share Document