Synthesis and stability studies of derivatives of the 2-sulfanyl-&ITcloso&IT-decaborate anion [2-B10H9SH]2-

By acylation of [2-B10H9SH](2) (1) with trifluoroacetic anhydride was synthesized the anion [B10H9 SCOCF3](2) (2). The alkaline and acid hydrolysis of the [B10H9S(CH2COOEt)(2)] anion leading to the formation of [B10H9S(CH2COOH)(2)] (3) gave evidence of high stability of sulfonium derivatives. While in phosphate buffer at pH = 5 the semi-hydrolysis time of thioesters [B10H9SCOCH3](2) , [B10H9SCOCF3](2) (2), and [B10H9SCOC6H5](2) were 600, 17 and 168 h. The substituted closo-decaborates were characterized by IR and NMR ( H-1, B-11, C-13) spectroscopy. The crystal structures of (Bu4N)3[B10H9(CH2COO)(2)H](2) (3) and Cs-5(Bu4N)[B10H9SC(O)CF3](3) (2a) were determined by X-ray diffraction. In structure 3, anions were associated via strong O-H center dot center dot center dot O hydrogen bonds into centrosymmetric hexacharged tetramers. In structure 2a, anions formed the environment of all cesium cations and chelated one of them due to Cs-O and Cs-HB bonds. (C) 2018 Elsevier B.V. All rights reserved.