Darstellung und Schwingungsspektren von Alkyl-und Rhodanohydrohexaboraten / Preparation and Vibrational Spectra of Alkyl and Rhodano Hydrohexaborates
Open Access
- 1 October 1988
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 43 (10) , 1327-1331
- https://doi.org/10.1515/znb-1988-1019
Abstract
Treatment of B6H6 2- with iodoalkanes and (SCN)2 in organic solvents affords the monosubstituted protonated hexaborates RB6H6 -, R = CH3, C2H5< C3H7, C4H9, C8H17 and SCN, respectively. The acidity constants of these weak Brönsted acids range for the alkylated species from 8.8 to 9.6, and for R = SCN the pka value is ~5. From basic solutions the salts Cs2RB6H5 can be precipitated, which show band patterns in the IR and Raman spectra typical for monosubstituted hydrohexaborates. The protonated compounds RB6H6 - are distinguished from the corresponding Brönsted bases RB6H5 2- by a high frequency shift of the BH stretching vibrations in the order of 100 cm-1. For Cs2(SCN)B6H5, S coordination of SCN- is supposed because of the high frequency of νCN: 2144 cm-1.Keywords
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