| | 1 | Author
| W. Preetz, M. Stallbaum | Requires cookie* | | | Title
| Darstellung und "B-NMR-Spektren perhalogenierter c/oso-Hexaborate B«X"Y6."2-, n = 0 -6 ; X * Y = Cl, Br, I  | | | | Abstract
| The mixed halogenohexaborates B6X"Y6_"2~, n = 1 -5 ; X ^ Y = Cl, Br, I, including most o f the pure stereoisomers for n = 2 -4 , are prepared for the first time by treatment o f the halo-hydrohexaborates B6X"H6_"2~, X = Cl, Br in aqueous alkaline solution with bromine and iodine or with halogenosuccinimides. The point symmetry is determined from the "B N M R spectra, which show characteristic features for hom ologous isostructural compounds. In the systems B6X"Y6_n2_ a considerable dispersion o f the "B signals is observed, for B(X) atoms to lower, for B(Y) atoms to higher field compared with B6X 62_ and B6Y 62~ (electronegativity X > Y), respectively. An additional chemical shift is caused by the mutual antipodal effect between pairs o f opposite B atom s carrying different substituents. From the systematic influ ences on the chemical shifts the "B N M R spectra o f the missing species fac-B6X 3Y 32_ are cal culated. | | | |
Reference
| Z. Naturforsch. 45b, 1113—1117 (1990); eingegangen am 6. März 1990 | | | |
Published
| 1990 | | | |
Keywords
| Mixed Halogenohexaborates, 11B N M R Spectra, A ntipodal Effect | | | |
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| default:Reihe_B/45/ZNB-1990-45b-1113.pdf | | | | Identifier
| ZNB-1990-45b-1113 | | | | Volume
| 45 | |
| 2 | Author
| W. Preetz, M. G. Hake | Requires cookie* | | | Title
| Darstellung, "B-NMR-und Schwingungsspektren der ctoso-Hexaborate |B6(SCN)6]J-und [B6(SeCN)6]2 | | | | Abstract
| On treatment o f [N(C4H 9)4][B6H 7] with (S C N)2 or (SeC N)2 in dichloromethane in the pres ence o f solid KOH the hexaborates [N(C4H 9)4]2[B6(SC N)6] and [N(C4H9)4]2[B6(SeC N)6] are formed. The octahedral structure for the B6 cage is proven by "B N M R spectroscopy. The chemical shifts in relation to BF3 • OEt2 o f —9,7 (SC N) and -10,2 ppm (SeC N) show the influ ence o f -I and +M effects o f the substituents. The S(Se) coordination is deduced from vibra tions within the substituents: vCN is observed at frequencies higher than 2100 cm -1 in the IR and Raman spectra, vcs at 662 and vcs at 556 cm "1 (intense IR bands). | | | |
Reference
| Z. Naturforsch. 47b, 1119—1121 (1992); eingegangen am 8. April 1992 | | | |
Published
| 1992 | | | |
Keywords
| Hexathiocyanatohexaborate, H exaselenocyanatohexaborate, 11B N M R Spectra, IR Spectra, Raman Spectra | | | |
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| default:Reihe_B/47/ZNB-1992-47b-1119.pdf | | | | Identifier
| ZNB-1992-47b-1119 | | | | Volume
| 47 | |
| 3 | Author
| ". B. Preparation, 13cN., M. R., Vibrational Spectra, W. Preetz, A. Franken, M. R. Ath | Requires cookie* | | | Title
| Darstellung, UB-, 13C-NM R-und Schwingungsspektren der c/öso-Hexaborate [B6H 5(C N )|2~ und m -[B 6H4(CN)2l2_ sowie Kristallstruktur von Cs2[B6H 5(CN)| | | | | Abstract
| of the c/oso-Hexaborates [B6H 5(CN)]2~ and c/s-[B6H 4(C N)2]2-, and the Crystal Structure o f Cs2[B6H 5(CN)] By reaction o f Cs2[B6H 6] with in situ generated dicyanogen in aqueous alkaline solution the m onocyanohydrohexaborate C s2[B6H5(CN)] and the dicyanohydrohexaborate cis-Cs,[B6H4(C N)2] are formed. The com pounds have been separated by ion exchange chrom atog raphy on diethylaminoethyl cellulose. The crystal structure o f Cs2[B6H5(CN)] was determined from single crystal X-ray diffraction analysis; monoclinic, space group P 2 Ja with a = 9.540(8), b = 9.977(3), c = 10.578(2) Ä, ß = 105.06(2)°. The B6 octahedron is compressed in the direction o f the nearly linear B -C N bond by about 5%, with bond lengths between 1.71 and 1.76Ä . The "B N M R spectra o f the two com pounds reveal the features o f substituted B6 cages with C4v and C2v point symmetry. In the l3C N M R spectrum o f Cs2[B6H 5(CN)] a quartet at -139 ppm with '/(C ,B) 92 Hz is observed. The IR and Raman spectra exhibit very strong CN stretching bands for Cs2[B6H5(CN)] at 2149, and for m -C s2[B6H4(C N)2] at 2170 c tr r 1. | | | |
Reference
| Z. Naturforsch. 48b, 598—6 (1993); eingegangen am 7. Dezember 1992 | | | |
Published
| 1993 | | | |
Keywords
| M onocyanohydrohexaborate, m -Dicyanohydrohexaborate, Crystal Structure, 11B N M R Spectra, Vibrational Spectra | | | |
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| default:Reihe_B/48/ZNB-1993-48b-0598.pdf | | | | Identifier
| ZNB-1993-48b-0598 | | | | Volume
| 48 | |
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