Solid-liquid phase diagrams were obtained for binary mixtures of octafluoronaphthalene with six polynuclear aromatic compounds, pyrene, phenanthrene, naphthalene, 1,5-naphthylenediamine, anthracene, and phenothiazine, and for mixtures of naphthalene and pyrene. The first four systems all formed well-defined 1:1 molecular complexes with congruent melting points.
On addition of SiO2 to TiO2 photocatalysts, it has been found that the yields of C2H6 and CH4 in the photocatalytic hydrogenation of propylene as well as that of 1-butene in the photocatalytic isomerization of cis-2-butene decrease simultaneously. This gives some support for the mechanisms for both reactions where [Ti3+–O−] pairs are important.
The microwave spectrum of (Z)-(acrylaldehyde oxime) was observed in the frequency region from 10 to 40 GHz. Several a-type R-branch transitions in the ground vibrational state were identified and the rotational constants in MHz were determined to be A=17430.7(35), B=3022.514(15), and C=2576.504(16). The conformation of (Z)-(acrylaldehyde oxime) has been plausibly deduced to be the s-trans Z-form from the rotational constants experimentally determined. The angle of C–C=N is discussed.
The extraction of copper(II) and zinc(II) with picrate ion and 12-crown-4(1,4,7,10-tetraoxacyclododecane) or 15-crown-5(1,4,7,10,13-pentaoxacyclopentadecane) into benzene or chloroform has been measured. The extraction of copper(II) is better than that of zinc(II), in spite of the similar ionic size, although the difference is much smaller than that in the extraction of these metal ions with β-diketones.
1H and 13C NMR spectra are reported for substituted 2-(2-nitrovinyl) thiophenes. The proton chemical shifts and coupling constants were correlated closely with those of methyl trans-3-(5-substituted 2-thienyl) acrylates. We have found that the additivity rule for 13C chemical shifts of simple substituted thiophenes is applicable to the shifts of the ring carbons in substituted 2-(2-nitrovinyl) thiophenes.
The reactions of some conjugated dienes with tetrabutylammonium dichlorobromate (1-) (1) were found to give the bromochloroalkenes in good yields, 1,2-addition predominating. Appreciable anti-Markownikoff adduct was obtained from 1,3-butadiene. An AdEC2-type mechanism is suggested.
Tributylstannyl alkyl or aryl sulfide and bis(tributylstannyl) sulfide were found to be useful to prepare aryl sulfides in good yields under the usual conditions of the palladium-catalyzed reaction with aryl bromides.
The substituent effects on chemical functions of benzo-15-crown-5 derivatives were found to be considerably large and often comparable to the ring-size effects. For example, 4′-aminobenzo-15-crown-5 transported K+ ion 14-times faster than 4′-nitrobenzo-15-crown-5, while 4′-nitrobenzo-18-crown-6 showed 12-times higher transport rate than 4′-nitrobenzo-15-crown-5.
CD spectral analysis of chromophoric derivatives of tetrapeptides related to the β-turn part of [D-Val1,1′]-and [D-Val1,1′, L-Phe4,4′]-gramicidin S indicated that they had very low preference for β-turn formation. The results suggested that neither analog could take gramicidin S-like β-sheet conformation. It seems noteworthy that the side-chain bulkiness of the 4th amino acid of a tetrapeptide affects the stability of β-turn.
In order to assess the validity of our regioselectivity rules for nucleophilic aromatic photosubstitution, 4-nitronaphthyl ethers were designed and their photochemical behavior was studied by applying frontier molecular orbital theory. The results provide supporting evidence for our rules.
Condensation of 6-formyl-7-hydroxy-2,2-dimethylchroman with ω-nitrostyrene in the presence of triethylamine yields 3-nitro-8,8-dimethyl-2-phenyl-7,8-dihydro-2H,6H-benzo[1,2-b:5,4-b′]dipyran which on treatment with hydrogen peroxide gives 3-hydroxy-8,8-dimethyl-2-phenyl-7,8-dihydro-4H,6H-benzo[1,2-6:5,4-b′]dipyran-4-one.
In the determination of cadmium by atomic absorption spectrophotometry(AAS), the interfering effects of different species can be completely eliminated by adding excess cyanide. The mechanism by which the cyanide eliminates interference by influencing the atomization process is discussed. Also the AAS for the analysis of cadmium in complex form is elaborated. The aim of this investigation is to achieve a determinate characterization of compound formation. The way to reach this purpose is the utilization of the continuous titration technique.
The Todd reaction, involving formation of a dialkyl phosphorochloridate by reaction of a dialkyl phosphonate with tetrachloromethane under basic conditions, has been determined to involve the intermediacy of the trichloromethanide anion.
The ion association complex formed between [Co(SCN)4]2− and 3,3′-(1,1′-biphenyl-4,4′-diyl)bis[2,5-diphenyl-2H-tetrazolium] dichloride, commercially known as neotetrazolium chloride, has been extracted into isobutyl methyl ketone and used for the photometric determination of 2.5–9.8 μg cm−3 cobalt at pH 3.5–5.0 (acetate buffer). Sandell’s sensitivity of the method (0.02 μg cm−2) is better than most of the other thiocyanate methods known so far. Interference of diverse ions has been studied. Using the higher tolerances of anions, many cations interfering in the other thiocyanate methods have been masked, thus making the present procedure more selective. The method has been applied to wire alloys.
Evidence has been obtained through the combined ESR and CIDEP techniques for the two distinct pathways in which trialkylsilyl radicals add to substituted p-benzoquinones via the carbonyl oxygen as well as the ring carbon–carbon double bonds. The results represent the first observation of CIDEP from organic radicals containing an organosilyl group in solution.