| Why are [P(C6H5)4]+N3- and [As(C6H5)4]+N3- Ionic Salts and Sb(C6H5)4N3 and Bi(C6H5)4N3 are Covalent Solids? A Theoretical Study Provides an Unexpected Answer |
04 MAR 2011 |
75 pages |
| Authors:
Karl O. Christe; Ralf Haiges; Jerry A. Boatz; H. D. Jenkins; Edward B. Garner; David A. Dixon; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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 | A recent crystallographic study has shown that, in the solid state, P(C6H5)4N3 and As(C6H5)4N3 have ionic [M(C6H5)4]+N3- type structures, whereas Sb(C6H5)4N3 exists as a pentacoordinated covalent solid. Using the results from density functional theory, lattice energy (VBT) calculations, sublimation energy estimates, and Born-Fajans-Haber cycles, it is shown that the maximum coordination numbers of the central atom M, the lattice energies of the ionic solids, and the sublimation energies of the ... |
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| High Energy Density Material Chemistry |
05 NOV 2006 |
16 pages |
| Authors:
Karl O. Christe; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| The overall objectives of this research are the syntheses and characterization of polynitrogen, high-nitrogen and high-oxygen energetic materials, useful as propellants or explosives ingredients. Excellent results were obtained in all areas and are summarized in 38 pubications and 2 patents. The chemistry of N5+ was developed and 13 new N5+ salts were prepared and characterized. It was demonstrated that N5+ cations can be combined with doubly charged anions, thereby doubling ... |
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| Experimental Evidence for Linear Metal-Azide Bonds. The Binary Group 5 Azides Nb(N3)5, Ta(N3)5, [Nb(N3)6]- and [Ta(N3)6]-, and 1:1 Adducts of Nb(N3)5 and [Ta(N3)5 with CH3CN] (POSTPRINT) |
27 APR 2006 |
7 pages |
| Authors:
Ralf Haiges; Jerry Boatz; Thorsten Schroer; Muhammed Yousufuddin; Karl Christe; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Whereas numerous binary transition metal azido-complexes have been reported, no binary Group 5 azides are known. Only a limited number of partially azide-substituted compounds of vanadium, niobium and tantalum have previously been reported. In this paper, we wish to communicate the synthesis and characterization of [Nb(N3)5], [Ta(N3)5] and their 1:1 adducts with CH3CN, and of the anions[Nb(N3)6]- and [Ta(N3)6]-. We also report the crystal structures of [Nb(N3)5(CH3CN)] and [PPh4][Nb(N3)6]and the ... |
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| Experimental Evidence for Linear Metal-Azide Coordination: The Binary Group 5 Azides [Nb(N3)5], [Ta(N3)5], [Nb(N3)6], and [Ta(N3)6], and 1:1 Acetonitrile Adducts [Nb(N3)5(CH3CN)] and (Ta(N3)5(CH3CN)) |
20 MAR 2006 |
7 pages |
| Authors:
Ralf Haiges; Thorsten Schroer; Muhammed Yousufuddin; Karl Christe; Jerry A. Boatz; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Whereas the existence of numerous binary transition metal azido-complexes has been reported, no binary Group 5 azides are known. Only a limited number of partially azide-substituted compounds of vanadium, niobium and tantalum have previously been reported. In this paper, we wish to communicate the synthesis and characterization of Nb(N3)5, Ta(N3)5 and their 1:1 adducts with CH3CN, and of the anions [Nb(N3)6]- and [Ta(N3)6]-. The crystal structures of [Nb(N3)5(CH3CN)] and [PPh4][Nb(N3)6] ... |
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| Preparation, Characterization, and Crystal Structures of the SO(3)NHF- and SO(3)NF(2)-Anions (PREPRINT) |
16 MAR 2006 |
29 pages |
| Authors:
Ralf Haiges; Ross Wagner; Jerry A. Boatz; Muhammed Yousufuddin; Markus Etzkorn; G. K. Prakash; Karl O. Christe; Robert D. Chapman; Mark F. Welker; Charles B. Kreutzberger; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Recently, a new class of high-energy-containing materials, gem-bis(difluoramino)-substituted heterocyclic nitramines, has gained attention as high-energy oxidizers: HNFX and TNFX have been successfully synthesized under strongly acidic conditions from their corresponding ketone derivatives using an excess of difluoramine. HNF2 is an unpredictably shock-sensitive and thermally unstable, gaseous compound which can be generated from different precursors, e.g., tetrafluorohydrazine, N,N-difluorourea, N,N-difluorocarbamates, or trityldifluoramine. Out of these precursors, only trityldifluoramine is a stable storable ... |
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| Preparation, Characterization, and Crystal Structures of the SO3NHF- and SO3NF2-Ions (POSTPRINT) |
16 MAR 2006 |
7 pages |
| Authors:
Ralf Haiges; Ross Wagner; Muhammed Yousufuddin; Markus Etzkorn; G.K. Prakash; Karl O. Christe; Robert D. Chapman; Mark F. Welker; Charles B. Kreutzberger; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Recently, a new class of high-energy-containing materials, gem-bis(difluoramino)-substituted heterocyclic nitramines, has gained attention as high-energy oxidizers: HNFX and TNFX have been successfully synthesized under strongly acidic conditions from their corresponding ketone derivatives using an excess of difluoramine. HNF2 is an unpredictably shock-sensitive and thermally unstable, gaseous compound which can be generated from different precursors, e.g., tetrafluorohydrazine, N,N-difluorourea, N,N-difluorocarbamates, or trityldifluoramine. Out of these precursors, only trityldifluoramine is a stable storable ... |
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| Triphenylmethyldifluoramine: A Stable Reagent for the Synthesis of gem- Bis(difluoramines) |
29 APR 2002 |
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| Authors:
G. K. Prakash; Markus Etzkorn; George A. Olah; Karl O. Christe; Stefan Schneider; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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 | The conversion of ketones into geminal bis(difluoramines) can be achieved under mild two phase reaction conditions by employing triphenylmethyldifluoramine as an in situ source of difluoramine. |
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| Improved Synthesis of CsN3 |
17 DEC 2001 |
7 pages |
| Authors:
Michael Gerken; Stefan Schneider; Thorsten Schroer; Karl O. Christe; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Cesium azide can conveniently be prepared from anhydrous CsF and (CH3)3SiN3 in SO2 solvent in high purity and yield. In this reaction, the initially generated SO2F(-) anion is converted in SO2 solvent to solvated azide, (SO2)(sub n)N3(-), which is labile and releases S02 under dynamic vacuum yielding pure CsN3. |
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| Synthesis of New Vinyl Monomers for Chemical Agent Sensing Applications |
NOV 2001 |
5 pages |
| Authors:
Thieo E. Hogen-Esch; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| The synthesis of styrene momomer p-vinylbenzoylacetophenone (monomer i) has been carried by the acetylation of 2- chloroethylbenzene and base elimination of the resulting 4-acetyl-2-chloroethylbenzene to give 4- acetylstyrene. This monomer was benzoylated by a sodium hydride mediated Claisen reaction with excess ethylbenzoate to give the monomer 1. This monomer that is of interest in ARO in sensing applications was characterized by proton NMR and by mass spectrometry. Each of the ... |
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| Photon-Harvesting Block Copolymers |
19 OCT 2001 |
7 pages |
| Authors:
Aaron W. Harper; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Our work has led to 1) the identification of several new and facile routes to preparing polyphenylene and poly(arylene vinylene)-type polymers and copolymers, 2) the development of highly-efficient organolanthanide complexes and dendrimers for both photon and excited-state energy harvesting. 3) the demonstration of triplet excited-state harvesting and electrophosphorescence in polymers used for light-emitting diodes, and 4) the development of two-photon active dyes for chemical sensing and photonic applications. It is ... |
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| A New Synthesis of Anhydrous Cesium Salts |
OCT 2001 |
9 pages |
| Authors:
Ralf Haiges; Karl O. Christe; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Contrary to ammonium salts many cesium salts are extremely hygroscopic. Consequently, anhydrous ammonium salts are readily available in anhydrous form by neutralizing the corresponding acids with ammonia, but their conversion to anhydrous cesium salts is difficult. |
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| Synthesis and Characterization of the First Examples of Perfluoroalkyl Substituted Trialkyl-Oxonium Salts, (CH3)2OCF3(+)Sb2F11(-) and (CH3)2OCF(CF3) 2(+) Sb2F11(-) |
16 MAR 2001 |
22 pages |
| Authors:
Joachim Hegge; Berthoid Hoge; Jeffrey A. Sheehy; Karl O. Christe; Rolf Minkwitz; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| In the superacidic HF/SbF5 system, methyl-trifluoromethylether forms at -78 deg C the new tertiary oxonium salt, (CH3)2OCF3(+)Sb2F11(-), that was characterized by Raman and multinuclear NMR spectroscopy and its crystal structure. The same oxonium salt was also obtained by methylation of CH3OCF3 with CH3F and SbF5 in HF solution at -30 to -10 deg C. Replacement of one methyl group in the trimethyloxonium cation by the bulkier and more electronegative trifluoromethyl ... |
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| Polynitrogen Chemistry, Synthesis, Characterization, and Crystal Structure of Surprisingly Stable Fluoroantimonate Salts of N5(+) |
01 MAR 2001 |
48 pages |
| Authors:
Ashwani Vij; William W. Wilson; Vandana Vij; Fook S. Tham; Karl O. Christe; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| The new N5(+) salt, N5(+)SbF6(-), was prepared from N2F(+)SbF6(-) and HN3 in anhydrous HF solution. The white solid is surprisingly stable, decomposing only at 70 deg C, and is relatively insensitive to impact. Its vibrational spectrum exhibits all nine fundamentals with frequencies that are in excellent agreement with the theoretical calculations for a five-atomic V-shaped ion of C2v symmetry. The N5(+)Sb2F11(-) salt was also prepared and its crystal structure was ... |
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| Development of New Nonlinear Optical Materials for Application to Sensor Protection |
SEP 96 |
46 pages |
| Authors:
Larry R. Dalton; Edward M. Healy; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| New ladder chromophores were synthesized and characterized for sensor protection applications. A similar effort was carried out for selected metallated pi-electron oligomers. Optical nonlinearity was characterized by both degenerate four-wave mixing (employing both femto- and picosecond pulses) and by pump-probe experiments. Large photo-induced absorption was observed for the new ladder chromophores. In all cases studied, the photo-induced absorption phenomena could be quantitatively described by a three level model. Relaxation to ... |
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| Composite Materials with Improved Properties in Compression |
05 NOV 93 |
58 pages |
| Authors:
William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
|
| Preparation of composite materials which have high strength in compression. Scientific approach is to prepare novel polymeric coupling agents. These will permit formation of multiple flexible covalent bonds between fibers as well as to matrix materials. In addition, these new coupling agents will possess elastomeric properties which may increase matrix toughness to fracture. Composite materials, Coupling agents, Novel carbosilane matrix, Strength in compression. |
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| Composite Materials with Improved Properties in Compression |
30 APR 91 |
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| Authors:
William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| This is a compilation of reports relating to preparation of composite materials which have high strength in compression. The scientific approach is used to prepare novel polymeric coupling agents. These will permit formation of multiple flexible covalent bonds between fibers as well as to matrix materials. In addition, these new coupling agents will possess elastomeric properties which may increase matrix toughness to fracture. |
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| Composite Materials with Improved Properties in Compression. Appendix 1. Cyclopropanation of Poly(1-Methyl-1-phenyl-1-sila-cis-pent-3-ene). Synthesis and Characterization of Poly(1-Methyl-3,4-methylene-1-phenyl-1-sila-cis-pent-3-ene) |
09 MAY 90 |
16 pages |
| Authors:
Xiugao Liao; Howard S. Lee; William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
|
| There is considerable interest in the chemical modification of polymers. While it has been possible to stereo specifically quantitatively add dichlorocarbene to the C-C double bonds of 1,4-polybutadiene as well as to those of poly(1,1-dimethyl-1-sila-cis-pent-3-ene) (II), it has not been possible to achieve complete cyclopropanation of the C-C double bonds of either 1,4- polybutadiene or II by use of the Simmons-Smith reaction. NMR spectra were obtained either on a Brucker ... |
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| Synthesis and Dimerization 2,3-Dimethyl-5-Silaspiro(4,4)nona-2,7-diene |
09 MAY 90 |
25 pages |
| Authors:
Young T. Park; Stephen Q. Zhou; Dong Zhao; Georges Manuel; Robert Bau; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Unsymmetrical 2,3-dimethyl-5-silaspiro(4,4)nona-2,7-diene (I) has been prepared by a dissolving metal reaction between 1,1-dichloro-1- silacyclopent-3-ene (III) and 2,3-dimethyl-1,3-butadiene. Ring opening reactions of I catalyzed by alkyllithium reagents and hexamethylphosphoramide (HMPA) have been explored. High yields of the dimer 2,3,12,13-tetramethyl-5,10- disiladispiro(4,4,4,4)octadeca-2,7,12,16-tetraene (II) are formed in these reactions. Dimerization of 2,3-Dimethyl-5-silaspiro(4,4)nona-2,7-diene, 5,10- disiladispiro(4,4,4,4)octadeca-2,7,12,16-tetraene, Structure by X-ray crystallography, Polymers, Composite materials, Organic chemistry, Oligomers, Appendix VII, Organometallic compounds. (JG) |
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| Composite Materials with Improved Properties in Compression. Appendix 5. Synthesis and Anionic Ring Opening Polymerization of 1-Germa-1,1-dimethyl(3,4,c) thienocyclopentane |
09 MAY 90 |
7 pages |
| Authors:
Stephen Q. Zhou; William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| While there has been extensive work on several types of polymers having silicon in the main chain due to their scientific and industrial importance, few studies on polymers containing germanium in the backbone have been reported. Despite this limited research, polygermanes have been observed to have interesting properties. For example, they have been found to be photoactive. They undergo photobleaching as well as to have thermochromic properties. Most recently, germylenes, ... |
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| Composite Materials with Improved Properties in Compression. Appendix 3. Synthesis of 3-Methylene-1,1-dichlorosilacyclobutane and 1,1- Dichlorosilacyclopent-3-ene |
09 MAY 90 |
12 pages |
| Authors:
Robert Damrauer; Andre Laporterie; Georges Manuel; Young T. Park; Roger Simon; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| Silacyclobutanes have played an important role in the development of modern silicon chemistry. For example, silacyclobutanes serve as precursors to carbon-silicon double bonded intermediates silenes as well as to pentacoordinate silicon anions in the gas phase. Silacyclobutanes also undergo facile ring opening polymerization. Despite the importance of this ring system surprisingly few functionalized silacyclobutanes and silacyclobutenes have been prepared. Similarly, there is considerable interest in 1-silacyclo-pent-3-enes due to their facile ... |
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| Composite Materials with Improved Properties in Compression. Appendix 2. Anionic Ring Opening Polymerization of 1-Silacyclopent-3-ene. Characterization of Poly(1-sila-cis-pent-3-ene) by 1H, 13C, and 29Si NMR Spectroscopy |
09 MAY 90 |
8 pages |
| Authors:
Steven Q. Zhou; Young T. Park; Georges Manuel; William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| 1-Silacyclopent-ene (I) undergoes anionic ring opening polymerization catalyzed by methyllithium/HMPA to yield poly(1-sila-cis-pent-3-ene) (II). II was characterized by 1H, 13C and 29Si NMR, TGA and elemental analysis. The low molecular weight of II permits end group analysis. Pyrolysis of II gives high char yields. These have been characterized by EDS. Keywords: Poly(1-sila-cis- pent-3-ene), Silicon carbide, Anionic ring, Polymerization, Perceramic polymer. (jes) |
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| Composite Materials with Improved Properties in Compression. Appendix 4. Addition of Difluorocarbene to Poly(1-Methyl-1-Phenyl-1-sila-cis-pent-3-ene). Characterization of Microstructures by 1H, 13C, and 19F and 29Si NMR |
09 MAY 90 |
3 pages |
| Authors:
Howard S. Lee; William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
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| There is considerable interest in the chemical modification of polymers (1-3). Dichloro (4-7) and difluorocarbene (8) add stereospecifically to the C-C double bonds of cis and trans-1,4-polybutadiene. Keywords: Difluorocyclopropanation, Poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene, Chemical modification, Polymers, Microstructure analysis. (jes) |
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| Composite Materials with Improved Properties in Compression: Synthesis and Dimerization 2,3-Dimethyl-5-Silaspiro(4.4)nona-2,7-diene |
09 MAY 90 |
26 pages |
| Authors:
Young T. Park; Stephen Q. Zhou; Dong Zhao; Georges Manuel; Robert Bau; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
|
| Unsymmetrical 2,3-dimethyl-5-silaspiro)4,4)nona-2,7-diene (I) has been prepared by a dissolving metal reaction between 1,1-dichloro-1- silacyclopent-3-ene (III) and 2,3-dimethyl-1,3-butadiene. Ring opening reactions of I catalyzed by alkyllithium reagents and hexamethylphosphoramide (HMPA) have been explored. Keywords: Dimerization of 2,3-dimethyl-5-silaspiro(4.4)nona-2,7- diene, 5,10-Disiladispiro)4,4,4,4)octadeca-2,7,12,16-tetraene, Structure by x- ray crystallography, Organometallic compounds, Composite materials. (jg) |
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| Aliphatic Nitrocompounds and Nitrated Reactive Intermediates |
17 FEB 88 |
7 pages |
| Authors:
George A. Olah; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
|
| The electrophilic nitration of alkanes and cycloalkanes with nitronium salts was studied. Nitration of the cage hydrocarbon adamantane served as a particularly suitable model for these studies. Alkyl and allylsilanes were found to undergo desilylative nitration with nitronium salts providing a mild, selective method to introduce nitro groups into aliphatic compounds. The study of nitrated reactive intermediates, particularly nitrocarbocations was also carried out. The first stable a-nitrocarbocation, the diphenylnitrocarbenium ion, ... |
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| Silicon Chemistry |
88 |
16 pages |
| Authors:
William P. Weber; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES LOKER HYDROCARBON RESEARCH INST
|
| Spirocyclosiloxanes have been prepared by insertion of 0=Si=0 under flash vacuum pyrolysis conditions into silicon-oxygen single bonds of cyclic siloxanes. We have prepared several new types of silicon containing polymers. 1, 3-Adamantyldimethylsiloxane copolymers have been prepared. These polymers are quite thermally stable. This may result from steric hindrance to the reversion reaction provided by the adamantane nucleus. Four novel types of unsaturated silyl substituted polymers have been prepared. Stereo- and ... |
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