- Soluble chlorofullerenes C60Cl2,4,6,8,10. synthesis, purification, compositional analysis, stability, and experimental/theoretical structure elucidation, including the X-ray structure of C1-C 60Cl10
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The efficacy of various analytical techniques for the characterization of products of C60 chlorination reactions were evaluated by (i) using samples of C60Cl6 of known purity and (ii) repeating a number of literature syntheses reported to yield pure C60Cl n compounds. The techniques were NMR, UV-vis, IR, and Raman spectroscopy, FAB, MALDI, LDI, ESI, and APCI mass spectrometry, HPLC, TGA, elemental analysis, and single-crystal X-ray diffraction. Most of these techniques are shown to give ambiguous or erroneous results, calling into question the composition and/or purity of nearly all C60Cl n compounds reported to date. The optimum analytical method for chlorofullerenes was found to be a combination of HPLC and either MALDI or APCI mass spectrometry. For the first time, the chlorination of C60 by ICl, ICl3, and Cl2 was studied in detail using dynamic HPLC analysis and APCI mass spectrometry. Suitable conditions were found for the preparation of the new chlorofullerenes 1,7-C60Cl2, 1,9-C60Cl2, 1,6,9,18-C60Cl4, and 1,2,7,10,14,24,25,28,29,31-C60Cl10. The latter compound was also studied by 13C NMR spectroscopy and X-ray diffraction, which led to the unambiguous determination of its asymmetric addition pattern. The unusual structure of C60Cl10 was compared with other possible isomers using DFT-predicted relative energies. These results, along with additional experimental data and an analysis of the DFT-predicted frontier orbitals of likely intermediates, were used to rationalize the formation of the new compound C60Cl10 from C60Cl6 and excess ICl without the rearrangement of any C-Cl bonds. For the first time, the stability of C60Cln compounds under a variety of conditions was studied in detail, leading to the discovery that they are, in general, very light-sensitive in solution. The X-ray structure of C 60Cl6 was also redetermined with higher precision.
- Kuvychko, Igor V.,Streletskii, Alexey V.,Shustova, Natalia B.,Seppelt, Konrad,Drewello, Thomas,Popov, Alexey A.,Strauss, Steven H.,Boltalina, Olga V.
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- Reactivity of Sulphuryl Chloride in Acetonitrile with the Elements
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Sulphuryl chloride in MeCN reacts with all but the most refractory elements to give mainly solvated chlorides at or below 300 K in contrast with SO2Cl2 alone which requires at least twice this temperature.There is evidence for an ionic mechanism based on analogy, thermochemistry, transport measurements and additive effects.The instability of these solutions leading to polymerization, together with its inhibition, is described.Sulphur dioxide formed in reactions seldom plays a reductive role apart from influencing formation of the mixed-valence Tl4Cl6.Semiquantitative kinetic measurements in different solvents emphasize the uniqueness of MeCN.For most elements attack is diffusion controlled across surface films giving a parabolic dependence on time which can be linearized if film growth is prevented by changing the solvent mix.The varied nature of these surface films vitiates any simple relation between rate and periodicity.Some applications are indicated.
- Woolf, Alfred A.
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p. 3325 - 3330
(2007/10/02)
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- Millimetr wave measurements of the rotational spectra of ClF, BrF, BrCl, ICl, and IBr
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The rotational spectra of all twelve stable isotopic species of ClF, BrF, BrCl, ICl, and IBr were abserved and measured in the millimeter wave region by means of a sensitive microwave spectrometer.Transitions were detected over a wide range of frequencies for molecules in both the ground vibrational state and several excites states.The rotational spectrum of each molecule was split by the nuclear quadrupole interaction.Altogether, 250 new lines were measured.These correspond to 136 purw rotational transitions.Values of the Dunham coefficients Y01, Y11, Y21, Y31, Y02, Y12, and Y03 were obtained from a computer analysis of the measured frequencies.From these coefficients a number of equilibrium constants were derived to significantly greater accuracy than in previous work.In particular, the equilibrium distance, re, was found to two or three more significant figures.
- Willis, Robert E.,Clark, William W.
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p. 4946 - 4950
(2007/10/02)
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