Synthesis of 12-Hydroxy and 12-Dioxane Derivatives of the closo-1-Carbadodecaborate(1-) Ion. Variations on the Plešek's Cobalt Bis(dicarbollide) Pattern
Synthesis of two new B(12) substituted derivatives of the closo-[1-CB11H12]- anion (1) is reported. The zwitterionic derivative containing dioxane ring {12-[O(CH2CH2)2O]+-1-CB11H11-}0 (2) was obtained in moderate yield using reaction of anion 1 with dioxane as solvent, induced by dimethyl sulfate. The anion [12-(HO)-1-CB11H11]- (3) was obtained in high yield upon treatment of the parent anion with 80% H2SO4 at high temperature. Both compounds containing reactive functionalities were designed to serve as useful synthons for a variety of synthetic purposes. The compounds were characterized by 11B and 1H high-field NMR, IR spectroscopy, mass spectrometry, melting points and TLC. Molecular structure of compound 2 was determined by single crystal X-ray diffraction analysis.