The method for synthesis of 2-sulfonium closo-decaborate anions derivatives with exo-polyhedral aminogroups

Abstract A method for the preparation of sulfonium derivatives of the closo-decaborate anion with the exo-polyhedral amino groups [B10H9S((CH2)nNH2)2]– (n = 1–3) has been developed. The method is based on the alkylation of the [B10H9SH]2– anion with N-bromoalkyl phthalimides and subsequent removal of the phthalimide protection with hydrazine. We could show that the interaction between the [B10H9SH]2– anion with bromomethyl phthalimide groups allowed us to prepare selectively mono-S-substituted sulfanyl derivatives [B10H9SCH2N(CO)2C6H4]2–. Due to the high stability of the sulfonium derivatives of the closo-decaborate anion, it is possible to obtain pechlorinated analogs of these compounds by chlorination of the salts n-Bu4N[B10H9S((CH2)nN(CO)2C6H4)2] (n = 1–3) with sulfuryl chloride in acetonitrile.