A systematic investigation of the reaction of SiF2 with ethylene and six methyl-substituted ethylenes. I. Product yields and mechanistic conclusions

1980 ◽  
Vol 58 (5) ◽  
pp. 419-424 ◽  
Author(s):  
William F. Reynolds ◽  
James C. Thompson ◽  
A. P. Gerald Wright
Keyword(s):  
Nmr Spectroscopy ◽  
Ground State ◽  
Systematic Investigation ◽  
Quartz Tube ◽  
Open Chain ◽  
Product Yields ◽  
Chain Compounds

SiF2 produced by the quartz tube reaction has been reacted with ethylene and six methyl-substituted ethylenes. All major products (polymers, disilacyclobutanes, disilacyclohexanes, and open chain compounds) have been characterized by a combination of 19F, 1H, 13C, and 29Si nmr spectroscopy. While polymer is always formed in highest yield, the relative proportions of other products vary significantly from alkene to alkene.Key observations concerning structures and stereochemistries and product yields are summarized. Consideration of this evidence leads to a mechanism involving attack of SiF2 on the olefin to form an excited silirane which either ring opens or relaxes to its ground state, followed in either case by further reaction.

A systematic investigation of the reaction of SiF2 with ethylene and six methyl-substituted ethylenes. II. Characterization of polymeric products, open chain organosilicon derivatives, and 1,2-disilacyclobutanes

1980 ◽  
Vol 58 (5) ◽  
pp. 425-435 ◽  
Author(s):  
William F. Reynolds ◽  
James C. Thompson ◽  
A. P. Gerald Wright
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Chemical Shifts ◽  
Systematic Investigation ◽  
Open Chain ◽  
Alkyl Substitution ◽  
Tail Structure

Polymers produced by the reaction of SiF2 with olefins have been characterized by 13C and 29Si nmr spectroscopy and have been found to have a regular head-to-tail structure with isolated SiF2 groups between olefin units. Only minor proportions of Si2F4 units are formed. The open chain organosilicon derivatives formed in the reaction are, with one exception, isomers of 1,2-disilacyclohexanes. The 1,2-disilacyclobutanes are formed stereospecifically with retention of alkyl stereochemistry. 19F chemical shifts can be predicted by additive chemical shift parameters for the effect of alkyl substitution.

Radiolysis of methylcyclopentane. III. Liquid phase mechanism and comparison of cycloalkanes

1968 ◽  
Vol 46 (20) ◽  
pp. 3235-3240 ◽  
Author(s):  
Gordon R. Freeman ◽  
E. Diane Stover
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Bond Cleavage ◽  
Open Chain ◽  
Methyl Substitution ◽  
Product Yields ◽  
Total Ionization ◽  
Gamma Radiolysis ◽  
G Value

The initial yields of the major products of the gamma radiolysis of liquid methylcyclopentane (MCP) at 25° are: G(H2) = 4.2, G(1-methylcyclopentene plus methylenecyclopentane) = 2.7, G(3- plus 4-methyl-cyclopentene) = 1.0, G(open chain hexene) = 1.0, and G(bimethylcyclopentyl) = 0.9. The effects of scavengers on the product yields are reported and the mechanism is discussed.The liquid phase radiolytic decompositions of cyclohexane (CH), methylcyclohexane (MCH), cyclopentane (CP), and MCP are compared. The net amount of C—C bond cleavage is much greater in the five-membered than in the six-membered rings. Methyl substitution on the ring reduces G(H2) by about one unit, mainly because of the formation of a type of ion (QH+) that does not yield hydrogen when neutralized by an electron. The QH+ type ions are formed in MCH and MCP, but not in CH and CP. In all the systems, another type of ion (N+) that does not yield hydrogen when neutralized by an electron is formed with a G value of about unity. The type of ion (PH+) that does yield hydrogen when neutralized by an electron has a G value of 3.4 in CH and CP, but only 2.0 in MCP. It is concluded that G(total ionization) is in the vicinity of 4.4 in the liquid compounds, virtually the same as the gas phase values.

Morpholines-(IV)

1971 ◽  
Vol 26 (11) ◽  
pp. 1140-1143 ◽  
Author(s):  
Riaz F. Abdulla ◽  
Alok N. Bannerji
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Beta Lactams ◽  
Aryl Substituent ◽  
Open Chain ◽  
H Nmr

Cyclodehydrohalogenation-beta-Lactams-Morpholin-3-ones-H'-NMR SpectroscopyN-Aryl-N-chloroacetyl-2-chlorophenacylamines (2) give morpholinones 3, or beta-lactams 4, depending upon the N-aryl-substituent. N-Phenyl-N- (2,3-dibromo-3-phenylpropionyl) -4-nitrophenacylamine did not undergo base-catalysed cyclization but gave, instead, the α,β-unsaturated, open-chain amide 5. N-Aryl-N-chloroacetyl-aminomethyl-2-naphthylketones afford only beta-lactams. The first attempt at the synthesis of a 2-chloro-3-oxo-morpholine resulted in the isolation of the 2-hydroxyderivative. The H1-NMR spectra of some more 3-oxo-morpholines have been recorded.

EXACT GROUND STATES OF ONE-DIMENSIONAL VALENCE-BOND-SOLID HAMILTONIANS

1987 ◽  
Vol 01 (05n06) ◽  
pp. 231-237 ◽  
Author(s):  
P.L. Iske ◽  
W.J. Caspers
Keyword(s):  
Ground State ◽  
Valence Bond ◽  
Ground States ◽  
Open Chain ◽  
State Correlation ◽  
One Dimensional ◽  
Degenerate Ground State ◽  
Closed Chain ◽  
Ground State Correlation ◽  
Valence Bond Solid

The ground state(s) of a Hamiltonian, introduced by Affleck, Kennedy, Lieb and Tasaki, in connection with the Valence-Bond-Solid (VBS) states, are explicitly given for the spin-1 chains. The structure of these ground states is a rather simple one. For a closed chain we find a unique ground state; for the open chain we find a fourfold-degenerate ground state. The ground state correlation function for the ring is calculated.

Cyano esters and malononitriles. IV. Cyano(fluorenyl)acetohydrazides and fluorenylpyrazolones

1977 ◽  
Vol 30 (10) ◽  
pp. 2255 ◽  
Author(s):  
N Latif ◽  
N Mishriky ◽  
M Hammad
Keyword(s):  
Phthalic Anhydride ◽  
Sodium Borohydride ◽  
Succinic Anhydride ◽  
Reductive Cleavage ◽  
Open Chain ◽  
Chain Compounds

Cyano(fluoren-9-yl)acetohydrazides cyclize readily under acid or basic conditions to give 3-amino-4-(9-substituted fluoren-9-yl)pyrazol-5(4H)- ones (3). Upon thermolysis of the hydrazides the pyrazolones and/or dimeric products are produced.��� The cyanoacetohydrazides condense with phthalic anhydride to give the 2-(fluoren-9-yl)-N-phthalimidoacetamides(7), whereas, with succinic anhydride, the open-chain compounds (10) are obtained which upon thermolysis afford the dimeric compounds (6). The acetamides (7) undergo unusual reductive cleavage with sodium borohydride affording the fluorenylpyrazolones (3). Electronic, infrared and N.M.R. spectra of the products are discussed.

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