Investigations in the cyclobutane series—X

Avram, M.; Dinulescu, I. G.; Dinu, Doina; Mateescu, Georg; Nenitzescu, Costin D.

doi:10.1016/s0040-4020(01)98532-1

Cited by 40 publications

(12 citation statements)

References 14 publications

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“…These spectral changes at wavenumbers 965, 1411, 1373, 1299, and 1897 cm 01 are attributed to a transvinylene double bond (trans R{CH|CH{R), methylene deformation influenced by an adjacent carbonyl group [RCH 2 {(CO){CH 2 {R], symmetric methyl deformation, and amorphous and crystallinity absorbance bands, respectively. 2,4,5,27,28 The FTIR subtracted absorbance values at some selected wavenumbers for irradiated LDPE film (absorbed doses of 60, 100, 200, 300, 420, 520, 710, and 880 kGy) are also presented in Table I. It appears quite clearly, from the obtained results in Figure 3 and Table I, that the g-ray irradiation caused slightly observable changes at all selected wavenumbers except for 1716 cm 01 , where the intensity of the absorbance increases clearly with increasing of absorbed doses.…”

Section: Resultsmentioning

confidence: 99%

Ultraviolet and infrared spectral analysis of irradiated polyethylene films: Correlation and possible application for large-dose radiation dosimetry

Abdel-Fattah

Ebraheem

Ali

et al. 1998

J. Appl. Polym. Sci.

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A detailed study was performed to develop the dosimetric characteristics of commercial low-density polyethylene film (LDPE), which is, by far, the most commonly used plastic for food and for many other-purpose packaging film, to be used as a film dosimeter for large-dose g-radiation dosimetry. The useful dose range extends up to 880 kGy. Correlations were established between the absorbed dose of g-radiation and the radiation-induced changes in LDPE measured using Fourier transform infrared (FTIR) and ultraviolet (UV) spectrophotometry. The results showed a significant dependence of the response on the selected readout tool of measurements whether FTIR (at 1716 cm 01 ) or UV (at 220 and 270 nm) as well as on the quantity used for calculation. The radiation-chemical yield of the ketonic carbonyl group produced in irradiated LDPE film was found to be 0.7 mmol/J. The assessment of the random uncertainty associated with the measurement of the dose response and the effect of relative humidity during irradiation on the dosimeter performance as well as the postirradiation stability at different storage conditions are discussed.

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Section: Resultsmentioning

confidence: 99%

Ultraviolet and infrared spectral analysis of irradiated polyethylene films: Correlation and possible application for large-dose radiation dosimetry

Abdel-Fattah

Ebraheem

Ali

et al. 1998

J. Appl. Polym. Sci.

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“…17 ' Hexamethyl dewar benzene very readily rearranges under acid catalysis, giving (90a) with sulphuric acid in methan01,'~~ and (90b) with hydrochloric acid in methylene chloride. 177 Toluene-p-sulphonic acid rearranges hexamethylprismane to (91),l 76 also obtained from (90b) and morpholine.' These observations help to rationalise the formation of (pentamethylcyclopentadiene)platinum dichloride, and (pentamethylcyclopentadieny1)rhodum chloride' 79 in treatment of hexamethyl dewar benzene with appropriate metal salts, and the formation of (90a) in reaction between but-2-yne and bis(benzonitri1e)palladium dichloride.…”

Section: (E) Routes To Macrocyclic and Bridged Compounds A Simple Syn...mentioning

confidence: 99%

“…Tetrachloro-and trichlorofluoro-cyclopropene are good dienophiles and subsequent cyclopropyl-ally1 transformations (Scheme 1) make the products synthetically useful.g0 cis-3,4-Dichlorocyclobutene reacts with dienes, apparently giving products having the stereochemistry as shown in, for example, (35). 91 Unusual dienes and dienophiles include norbornadiene-2,3-dicarboxylic anh~dride,'~ isophorone e n a m i ~~e , ~~ and dimethylfulvene in its addition to dimethyl acetylenedicarboxylate. 94 Others.…”

Section: Ringmentioning

confidence: 99%

Chapter 11. Alicyclic compounds

Brown¹

1968

Annu. Rep. Prog. Chem., Sect. B

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Useful quantitative data on heats of hydrogenation and combustion have appeared ; this allows the estimation of strain energy effects for bicyclo[l,l,O]butane,' bicyclo[ 2,1,O] pentane, ' quadricyclene,l and a number of C4H6 cyclic hydrocarbons.2 The strain energy in the bridgehead olefin bicyclo[3,3,1]non-1-ene is estimated3 from the heat of acetic acid addition to be 12 kcal. per mole. Quantitative assessment of strain and conformational effects has allowed estimation of activation energies for a variety of small ring thermolyse~.~ Assumption of a non-concerted diradical mechanism shows good fit with experiment in all cases studied except those of cyclobutene ring opening and rearrangement of cis-1 -methyl-2-vinylcyclopropanes, which are much more ready and, therefore, follow a concerted path. Differential thermal analysis may be used to measure activation energies and heats of reaction simultaneously, as in the dimerisation of cyclopentadiene and the endo,exo-cyclopentadiene dimer isomerisati~n,~ and in thermolyses of hexamethyl dewar benzene and hexamethylprismane.6Reviews of fulvenes,' cyclopropanols,8 metal-catalysed reactions of norbornadiene,' 1,2-and l,.l-addition to conjugated dienes," the steric course of cyclohexenone additions," and solvolysis of norbornen-7-yl systems' have been produced. An issue of Angewandte Chernie13 is devoted to small ring chemistry.Conformational Analysis.-The sophistication and accuracy in computersimulation of energy and geometry in cyclic systems increases ; Hendrickson has presented more detailed analysis of medium rings and of methyl-substituted cycloalkenes, coupled with a full topological analysis of conformer interconversion pathways. l4 Allinger's school has refined the Westheimer-Hen-' '

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“…We report here a simple method for afford the 'linear' dimer (4) or ( 5 ) . 2 We have recently found a the synthesis of cisoid, transoid, transoid-and simple and efficient method for the nickel-catalysed coupling all-cisoid-trimers (6) and (7) of benzocyclobutene (2) by of alkenyl, aryl, benzyl, and phenacyl halides3 and cyclo-nickel-catalysed cyclo-trimerization. A typical procedure involved treatment of the dibromide (1) (1 equiv.)…”

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confidence: 99%