摘要:

Rate constants,kQ, have been determined for the deactivation of singlet oxygen in carbon tetrachloride by a range of transition metal complexes. The singlet oxygen was produced by flash photolysis of air-saturated carbon tetrachloride solutions with methylene blue as sensitizer, and the decay followed by observing the concentration of the accepter 1,3-diphenyliso-benzofuran at 435 nm. The high rate constants of certain diamagnetic nickel complexes are accounted for by a spin-allowed transfer of electronic energy from singlet oxygen to the complex. Rate constants have also been determined for the deactivation of triplet pentacene by a number of these metal complexes. The triplet pentacene was produced by flash photolysis of dilute solutions of pentacene in benzene and the decay monitored at 492 nm. The rate constants for quenching of triplet pentacene are generally lower than those for quenching of singlet oxygen but there is a good correlation between the two sets of results. Both processes appear to proceed by way of electronic energy transfer without the intervention of complex formation between donor and accepter.

ISSN:0008-4042    

DOI:10.1139/v78-261

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The crystal and molecular structure oftrans-chloro(3-hydroxypropyl-N,N-dimethylaminocarbene)bis(dimethylphenylphosphine)platinum(II) hexafluorophosphate has been determined from three-dimensional X-ray data collected on an automated four circle diffractometer using CuKα radiation. The compound crystallizes in the orthorhombic space groupPna21, withZ = 4, and cell dimensionsa = 14.403(2),b = 12.631(2), andc = 16.151(2) Å. Full matrix least-squares refinement onFgave a final conventionalRfactor of 0.047 for 3442 observations withI > 3σ(I). The cation coordination geometry is square planar, with the carbene ligand lying approximately perpendicular to the plane. The Pt—Cl bond length is 2.356(4) Å and the Pt—C(carbene) distance is 1.978(12) Å. The C(carbene)—N bond length is 1.293(16) Å. These dimensions are discussed in terms of thetransinfluences of the carbene and chloride ligands and the bonding in the carbene species.

ISSN:0008-4042    

DOI:10.1139/v78-262

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Hydrogen fluoride reacts with perchloric acid yielding an incongruently melting compound (−117 °C); by ir spectroscopy, we demonstrate that HClO4is linked to a (HF)npolymer through a weak hydrogen bond. The liquid of the same composition still contains a small amount of the complex; HF is really a base forHClO4. The reactivity of MeNO2was studied in this liquid acidic medium and the nitromethane is found to be somewhat stronger than HF.

ISSN:0008-4042    

DOI:10.1139/v78-263

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Several synthetic routes to anthraniloylanthranilamide (6) are described; the problems involved ino-aminobenzoylation reactions are explored. Reduction ofN-(o-nitrobenzoyl)anthranilamide by stannous chloride gave a low yield of6, which was also obtained in low yield by reaction of isatoic anhydride witho-aminobenzamide. The possible use ofO-(o-aminobenzoyl)hydroxylamines foro-aminobenzoylation was investigated but proved impractical. Diazotisation of6affords 3-(o-carbamoylphenyl)-1,2,3-benzotriazin-4(3H)-one (2), which undergoes base-catalysed cyclisation to the quinazolino[3,2-c]benzotriazine (4). The conversion2 → 4probably involves the isomeric quinazolino[1,2-c]benzotriazine (3), which could not be isolated.

ISSN:0008-4042    

DOI:10.1139/v78-264

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Tryptamine derivatives3a–cand4a,4b,4dhave been converted into the indoleN-p-carbomethoxybenzyl derivatives1a,1b,1g, and2a,2b,2c, respectively, using dianion and phase-transfer catalytic methodologies. Treatment of these compounds with lithium iodide and sodium cyanide in refluxing dimethylformamide gave the corresponding carboxylic acids1d,1e,1h, and2d,2e,2f. The serotonin analogue1fwas obtained by catalytic debenzylation of1h. These products may be useful haptens for eliciting specific antibodies to indolealkylamines.

ISSN:0008-4042    

DOI:10.1139/v78-265

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The first total synthesis of the spirosesquiterpene (−)-acorenone (1) is described. The critical step involves a spiroannelation of the enamine of aldehyde11with 1-methoxy-3-buten-2-one (16) in the presence of acetic acid to give ketone17. Reaction of17with methylmagnesium iodide followed by treatment of the resultant alcohol18withp-toluenesulfonic acid in refluxing benzene leads directly to1in good overall yield. As the starting material for the preparation of the cyclopentanoid aldehyde11was (+)-limonene the final product is optically active and thus the absolute configuration of naturally occurring (−)-acorenone (1) is established. The preparation of a number of other optically active cyclopentanoid monoterpenes (4and13) is also described.

ISSN:0008-4042    

DOI:10.1139/v78-266

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Chloryl fluoride, ClO2F was studied in its solid phase by X-ray and neutron diffraction techniques and by vibrational spectroscopy.The powder diffraction patterns of ClO2F were indexed by comparison with ClF3. At 77 K, the parameters of the monoclinic cell of ClO2F are as follows:a = 8.85 ± 0.02 Å,b = 6.17 ± 0.02 Å,c = 4.62 ± 0.01 Ǻ, β = 95.0 ± 0.1°,Z = 4. This cell, which can be thought as arising from a slight monoclinic deformation of the orthorhombic cell of ClF3, is consistent with the density measurements also performed on ClO2F and ClF3.The space groupwas found to be the best compatible with both the vibrational data and the lines observed in the powder diffraction patterns for ClO2F in the polycrystalline state

ISSN:0008-4042    

DOI:10.1139/v78-267

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Far infrared absorption and Raman spectra were recorded forortho- andmeta-disubstituted benzene ClC6H4Cl, ClC6H4Br, and BrC6H4Br from 15 to 250 cm−1at different temperatures (80–300 K). From spectroscopic evidence, one phase transition is found for both theo- (200 K) and them-dichlorobenzene (220 K), and two for theo-chlorobromobenzene (185 and 222 K).

ISSN:0008-4042    

DOI:10.1139/v78-268

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The synthesis of 10-methoxycarbonyl-1,7,7-trimethyl-cis-2-decaIone (6c) is described as well as that of the correspondingtransisomer. The stereochemistry of catalytic hydrogenation of the carbon–carbon double bond of Δ1,9-2-octalones is shown to be controlled by the angular substituent at position 10.Thecis-decalin system is considered as a synthon for the DE ring system of certain pentacyclic triterpenes.

ISSN:0008-4042    

DOI:10.1139/v78-269

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Decompositions of tetramethyl-2-tetrazene (TMT) under acidic conditions were investigated by product analysis and by nmr and esr spectroscopic monitors. Photolysis in acetonitrile containing trifluoroacetic acid generated the dimethylaminium radical which added efficiently to an olefinic double bond. Some adducts contained a (CH3)2NCH2— moiety, the immediate precursor of which could be CH2=N(CH3)2+species. Photolytic addition of TMT to nor-bornenes generated 2-norbornyl radicals that underwent coupling through theexoorendoside to give the dimers. Thermal decomposition in sulfuric acid in the presence of toluene gaveN,N-dimethyltoluidines,N-methylphenethylamine, benzyltoluenes, and a plethora of other minor products in addition to a large amount of formylidene methylamine. The last compound was the major product when thermal decomposition of TMT was carried out in trifluoroacetic acid in the presence of toluene or anisol; amination products of aromatic substrates were low and contained onlyorthoandparaisomers. TMT dissolved in these solvents exhibited the esr signal of the stable(the tetrazene cation radical) which did not react with cyclohexene. In concentrated sulfuric acid, TMT was decomposed in less than 15 min giving formylidene methylamine and dimethylamine as shown by nmr. In trifluoroacetic acid, the esr signal of tetramethylhydrazine cation radicalemerged after the TMT solution was irradiated; no dimethylaminium radical signal could be detected. The relationship ofandwith formation of the observed products remains unclear.

ISSN:0008-4042    

DOI:10.1139/v78-270

出版商:NRC Research Press    

年代:1978

数据来源: NRC