Anomalous ozone degradations of 1-chloro substituted conjugated dienes in methanol

1987 ◽  
Vol 65 (3) ◽  
pp. 487-490 ◽  
Author(s):  
Karl Griesbaum ◽  
Ashis R. Bandyopadhyay
Keyword(s):  
Conjugated Dienes ◽  
Double Bonds ◽  
Cleavage Reactions ◽  
Single Bonds

Diozonolyses in methanol of (E)-4-chloro-2,3-dimethyl-1,3-hexadiene (4a) and of (4E)-5-chloro-3,4-dimethyl-2,4-heptadiene (4b) resulted in complete cleavage of the double bonds and of the single bonds of the respective diene systems. The course of these anomalous cleavage reactions has been established by step-wise ozonolyses of these dienes, and by the identification of labile methoxy hydroperoxides as intermediates.

The Change in the Raman Spectra of Chloroprene and Isoprene in the Polymerization Process

1943 ◽  
Vol 16 (4) ◽  
pp. 841-847
Author(s):  
A. Gantmacher ◽  
S. Medvedev
Keyword(s):  
Raman Spectrum ◽  
Double Bond ◽  
Raman Spectra ◽  
Polymer Molecule ◽  
Polymerization Process ◽  
High Polymer ◽  
Single Bond ◽  
Double Bonds ◽  
Continuous Background ◽  
Single Bonds

Abstract 1. When chloroprene and isoprene polymerize, besides the frequency characterizing the conjugate double bond in the monomer, there appears a higher frequency corresponding to the isolated double bond in the polymer. In the polymerization process, the intensity of the frequency of the conjugate double bond decreases and the intensity of the frequency of the isolated double bond increases. Because of the increase in the number of single bonds in the polymer, the intensity of the frequency of the single bond 1005 in the polymer is considerably greater than in the monomer. 2. Even in the case of the samples with high polymer contents (greater than 50 per cent), the intensity of the frequency of the conjugate double bond is considerably greater than the intensity of the frequency of the isolated double bond. This is attributable to the fact that part of double bonds disappear during polymerization. 3. The Raman spectra of the chloroprene and isoprene polymers differ essentially from those of the monomers. To characterize the frequencies of vibration in the polymer molecule, it is essential to investigate its Raman spectrum in a medium free of the monomer. 4. The formation of highly polymeric molecules on polymerization does not result in an increase in the intensity of the continuous background in spectrograms.

Synthese und Struktur von Cäsium-1,5-bis(p-tolyl)pentaazadienid, Cs+(tolN5tol)- / Synthesis and Structure of Cesium 1,5-Bis(p-tolyl)pentaazadienide, Cs+(tolN5tol)-

1988 ◽  
Vol 43 (5) ◽  
pp. 529-532 ◽  
Author(s):  
Raimund Schmid ◽  
Johannes Beck ◽  
Joachim Strähle
Keyword(s):  
Aqueous Solution ◽  
Zigzag Chain ◽  
Double Bonds ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Crystalline Precipitate ◽  
Concentrated Solution ◽  
Single Bonds

Cs+(tolN5tol)- (1) is formed as a yellow crystalline precipitate after addition of a concentrated aqueous solution of CsCl to a concentrated solution of 1,5-Bis(p-tolyl)pentaazadiene(1,4) in ammonia. 1 crystallizes in the orthorhombic space group Pccn with a = 3169(1), b = 434.3(2), c = 1109.4(7) pm, Z = 4. The structure contains (tolN5tol)- anions and Cs+ cations both occupying two-fold axes. The all-trans N5 zigzag chain is planar with localized double bonds N1 - N2 and N2′ - N1′ of 127.7 pm and shortened single bonds N2-N3 and N3-N2′ of 136.9 pm. The tolyl substituents are titled by 25.5° against the plane of the N atoms. Cs+ is surrounded in a square antiprismatic arrangement by eight N atoms of four N5 chains with distances Cs-N in the range of 314.6 to 366.2 pm.

On the π-Electron Content of Bonds and Rings in Benzenoid Hydrocarbons

2004 ◽  
Vol 59 (4-5) ◽  
pp. 295-298 ◽  
Author(s):  
Ivan Gutman ◽  
Tetsuo Morikawa ◽  
Susumu Narita
Keyword(s):  
Bond Order ◽  
Membered Ring ◽  
Electron Content ◽  
Bond Orders ◽  
Double Bonds ◽  
Benzenoid Hydrocarbons ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Carbon Carbon Bonds ◽  
Single Bonds

The Pauling bond order can be viewed as a measure of the π-electron content of the respective carbon-carbon bond. In benzenoid hydrocarbons its values lie between 0 (in the case of essential single bonds) and 1 (in the case of essential double bonds). If the benzenoid molecule does not possess essential single and double bonds, then the Pauling bond orders are greater than 0 and less than 1, but may assume values arbitrarily close to 0 and 1. The π-electron content of a ring is equal to the sum of the π-electron contents of the carbon-carbon bonds forming this ring. We show that in benzenoid hydrocarbons the π-electron content of any (six-membered) ring lies between 0 and 5.5. If the molecule does not possess essential single and double bonds, then the π-electron content of any ring is greater than 0 and less than 5.5, but may assume values arbitrarily close to 0 and 5.5.

Übergangsmetall-Methylen-Komplexe, LI [1]. Carbocyclische Carbene, Carben-Brücken, kleine Kohlenwasserstoff-Liganden und Metallacyclen: Beispiele einer umfassenden Synthesekonzeption / Transition Metal Methylene Complexes, LI [1]. Carbocyclic Carbenes, Carbene Bridges, Small Hydrocarbon Ligands, and Metallacycles: Examples of a General Synthetic Concept

1983 ◽  
Vol 38 (11) ◽  
pp. 1392-1398 ◽  
Author(s):  
Wolfgang A. Herrmann ◽  
Johann Plank ◽  
John L. Hubbard ◽  
Gangolf W. Kriechbaum ◽  
Willibald Kalcher ◽  
...  
Keyword(s):  
Transition Metal ◽  
Double Bonds ◽  
General Applicability ◽  
Bridging Ligands ◽  
Metal Centers ◽  
Mild Conditions ◽  
Metal Metal ◽  
Hydrocarbon Chemistry ◽  
Rearrangement Processes ◽  
Single Bonds

Abstract Carbene transfer from aliphatic diazoalkanes upon coordinatively unsaturated metal centers is a general synthetic concept that provides straight-forward routes into organo-metallic hydrocarbon chemistry. A comparison focussing on several key reactions of general applicability demonstrates that mononuclear organometal substrates add carbenes that may act as bridging ligands (e.g., compound 6) if they arise from ω,ω'-bisdiazoalkanes. By way of contrast, metal-metal double bonds cleanly form dimetallacyclo-propane-type derivatives under very mild conditions (7-9). The broadest variety of structures is finally encountered with metal-metal triply bonded precursors such as the molybdenum compounds 3: here, the initial diazoalkane adducts are subject to further rearrangement processes commonly leading to metal-metal single bonds (11) or causing irreversible cleavage of the dinuclear metal systems (10).

Monoozonides of chloro-substituted conjugated dienes: preparation, stability, and some chemical reactions

1986 ◽  
Vol 64 (8) ◽  
pp. 1553-1559 ◽  
Author(s):  
Karl Griesbaum ◽  
Ashis R. Bandyopadhyay ◽  
Martin Meister
Keyword(s):  
Chemical Reactions ◽  
Conjugated Dienes ◽  
Double Bonds ◽  
Subsequent Reaction

The chlorodienes (E)-4-chloro-3-methyl-1,3-hexadiene (5a), (E)- and (Z)-4-chloro-2,3-dimethyl-1,3-hexadiene (5b/6b), (E,E)-5-chloro-4-methyl-2,4-heptadiene (5c), (4E)- and (4Z)-5-chloro-3,4-dimethyl-2,4-heptadiene (5d/6d), chloroprene (11a), and 2-chloro-3-methyl-1,3-butadiene (11b) are selectively ozonized at the non-chlorinated double bonds to give the corresponding monoozonides 7, 8, and 12. Further ozonolyses of the monoozonides of 5b and of 11b in methanol as well as epoxidation of the monoozonide of 5b and subsequent reaction of the resulting chloroepoxide with AgBF4 are described.

Natural and Synthetic Rubber. I. Products of the Destructive Distillation of Natural Rubber

1929 ◽  
Vol 2 (3) ◽  
pp. 441-451 ◽  
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Experimental Data ◽  
Natural Rubber ◽  
Atmospheric Pressure ◽  
Experimental Results ◽  
Double Bonds ◽  
Synthetic Rubber ◽  
Single Bonds ◽  
Natural And Synthetic

Abstract Two hundred pounds of pale crepe rubber have been destructively-distilled at atmospheric pressure. The distillate was fractionated and its components identified from C5 to C10, as shown in the table. Assuming that the Staudinger formula is correct, that the single bonds furthest from the double bonds are the weaker spots and that the formation of six-carbon rings is favored, it has been shown that nearly all of the compounds actually isolated could be predicted. The experimental results, together with forthcoming experimental data, are expected to be used to throw light upon the formula of the rubber molecule.

Addition of thianthrene cation radical to non-conjugated dienes—Part II: Addition to two double bonds

2006 ◽  
Vol 27 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Bing-Jun Zhao ◽  
Henry J. Shine ◽  
John N. Marx ◽  
Anna T. Kelly ◽  
Cristina Hofmann ◽  
...  
Keyword(s):  
Cation Radical ◽  
Conjugated Dienes ◽  
Double Bonds
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