Darstellung, 11B-, 13C-, 1H-NMR- und Schwingungsspektren von Monoethoxyhydro-closo-Dodecaborat(2–) sowie Kristallstruktur von [(C5H5N)2CH2][B12H11(OC2H5)] |
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Authors: | W. Preetz O. Haeckel |
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Abstract: | Preparation, 11B, 13C, 1H NMR and Vibrational Spectra of Monoethoxyhydro-closo-dodecaborate(2–), and the Crystal Structure of [(C5H5N)2CH2][B12H11(OC2H5)] By treatment of Na2[B12H12] with dry HF in ethanol Na2[B12H11(OC2H5)] is formed which has been separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from the starting compound and by-products. The X-ray structure determination of [(C5H5N)2CH2][B12H11(OC2H5)] (monoclinic, space group P21/m, a = 9.1906(3), b = 12.6612(8), c = 9.3640(12) Å, β = 112.947(6)°, Z = 2) reveals the complete ordering of the anion sublattice. The 11B nmr spectrum exhibits the characteristic feature (1:5:5:1) of a mono substituted B12 cage with a strong down-field shift of ipso-B at +6.5 ppm. In the 13C nmr spectrum a triplet at 67.9 ppm of the methylene group and a quartet at 19.5 ppm of the methyl group is observed. Correspondingly, the 1H nmr spectrum shows two multiplets at 3.7 and 1.3 as expected for an ethoxy substituent, and a multiplet at 2.1 ppm due to the protons of the boron cluster. The i.r. and Raman spectra exhibit strong CH stretching vibrations between 2 963 and 2 863 cm?1, and in the i.r. spectrum the CO and BO stretching frequencies of the B? O? C bridge are observed at 1 175 and 1 140 cm?1. |
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Keywords: | Ethoxy-undecahydro-closo-dodecaborate(2– ) Crystal Structure 11B, 13C, 1H nmr Spectra Vibrational Spectra |
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