Reaction of atomic oxygen with cyclopentadiene

The reaction of 1,3-cyclopentadiene (CPD) with ground-state atomic oxygen O(³P), produced by mercury photosensitized decomposition of nitrous oxide, was studied. The identified products were carbon monoxide and the following C₄H₆ isomers: 3-methylcyclopropene, 1,3-butadiene, 1,2-butadiene, and 1-butyne. The yield of carbon monoxide over oxygen atoms produced (?_CO) was equal to the sum of the yields of C₄H₆ isomers in any experiment. ?_CO was 0.43 at the total pressure of 6.5 torr and 0.20 at 500 torr. We did not succeed in detecting any addition products such as C₅H₆O isomers. It was found that 3-methylcyclopropene was produced with excess energy and was partly isomerized to other C₄H₆ isomers, especially to 1-butyne. The excess energy was estimated to be about 50 kcal/mol. The rate coefficient of the reaction was obtained relative to those for the reactions of atomic oxygen with trans-2-butene and 1-butene. The ratios k_CPD+O/k_{trans-2-butene+O}= 2.34 and k_CPD+O/k_1-butene+O = 11.3 were obtained. Probable reaction mechanisms and intermediates are suggested.     

Luminescence due to isoelectronic impurities in CuCl

Luminescence spectra have been investigated for CuCl doped with the isoelectronic halogen impurities, Br and I. Broad emission bands characterized by a multiphonon structure were found at around 4200 and 4010 Å in Br- and I-doped samples, respectively, at 4.2 K. From the observed features of these luminescences, they are ascribed to the radiative decay of excitons bound at halogen impurities in CuCl. The roles of these isoelectronic impurities in CuCl are discussed in relation to a theory of excitons in a binary mixed crystal.     

Trifluoromethyl trifluoromethanesulfonate (CF3SO2OCF3)

Trifluoromethyl trifluoromethanesulfonate ($\text{1}$) was synthesized by the reaction of silver trifluoromethanesulfonate with trifluoromethyl iodide in a benzene solution. Reaction of $\text{1}$ with an enamine gave trifluoromethanesulfonyl compound. This is the first example of SO₂-O bond fission of alkyl trifluoromethanesulfonate.     

Laser-induced fluorescence spectroscopy of the E band of the Ã-X̃ transition of SO2 cooled rotationally in a supersonic jet

The rotationally resolved, laser-induced fluorescence spectrum of the E band of the $\text{A}\text{?}{}^1\text{A}{}_2\text{-}\text{X}\text{?}{}^1\text{A}{}_1$ transition of SO₂ seeded in a supersonic jet was observed, and each rotational line was assigned on the basis of the ground state combination differences and the relative intensity data as a function of the rotational temperature. It was demonstrated that the line congestion was reduced significantly in the spectrum of the jet, and some of the lines, e.g., ^rR₀(0), were assigned unambiguously. This makes it possible to determine the vibronic band origin with an error of less than 0.2 cm^?1.     

Synthesis of perfluorochemicals for use as blood substitutes,part II: electrochemical fluorination of partly fluorinated compounds

Electrochemical fluorination of 2-methoxy-1,1,1-trifluoro-2-(F-methyl) octane gave the corresponding perfluorinated ether in 27% yield, along with cyclic by-products in 9%. A mixture of partly fluorinated tertiary amines, consisting of 1-dipropylamino-F-1-propene and 1-dipropylamino-2-hydryl-F-propane, did not afford a superior yield of tri(F-propyl)amine compared to the unfluorinated tripropylamine. 1-Diethylamino-2-(F-methyl)-F-1-pentene was fluorinated to give the corresponding F-tertiary amine in fairly good yields, together with 1-di(F-ethyl)amino-2-hydryl-2-(F-methyl)-F-pentane and their fragmented products. The study indicates that blocking of the α-carbon atom of an ether with F-methyl groups seems to reduce fragmentation, resulting in good yields of an unrearranged product. However, partial fluorination of a tertiary amine prior to electrochemical fluorination rather allows high yields of undesired by-products, as far as our experiments were concerned.     

Raman spectra of the librational phonon modes in isotopically mixed anthracene-PMDA crystals

Raman spectra have been measured for the librational phonon modes in the charge transfer complex anthracene-PMDA crystals. Utilizing the isotopically mixed crystals, assignments are made for the six librational Raman modes. From the observed isotopic effects of the Raman lines, it is concluded that the dispersions of these librational modes are highly anisotropic along the direction perpendicular to the molecular stack axis.     

Electro-reflectance spectra of one-dimensional excitons in polydiacetylene crystals

Electro-reflectance spectra are reported for two spectroscopically-distinct forms of a polydiacetylene, poly(5,7-decadiyne-1,12-diol-bis phenylurethane). An electric field parallel to the polymer chain axis produces in both types of single crystals (1) a Stark shift of the main absorption peak and (2) a new absorption peak on the high energy side of the main peak. Using a one-dimensional exciton model, the main peak is assigned to the lowest ^tB_u exciton and the field-induced peak is assigned to the higher dipole-forbidden ^tA_g exciton, both associated with the one-dimensional π-electron bands on the polymer chains.     

Synthesis and properties of n-trimethylgermylmethyl-n-nitrosourea,a germanium analogue of n-neopentyl-n-nitrosourea

The rate for hydrolysis, chemoselectivitly toward nucleophiles, and partition property of N-neopentyl-, N-trimethylsilylmethyl-, and N-trimethylgermylmethyl-N-nitrosoureas were compared. The latter two compounds are silicon and germanium analogues of the neopentyl derivative. The substitution effect of Ge in place of Si or C are discussed on the chemical and physicochemical properties.