A Spirocyclic Borate and a Dihydroborate Derived from the 1,2‐Diselenolato‐1,2‐dicarba‐ closo ‐dodecaborane(12) Dianion [1,2‐(1,2‐C 2 B 10 H 10 )Se 2 ] 2– : Structures, NMR Spectroscopy, and DFT Calculations

Abstract The reaction of the diselenolato‐1,2‐dicarba‐ closo ‐dodecaborane(12) dianion with BF 3 –OEt 2 affords selectively a spirocyclic bis(1,2‐dicarba‐ closo ‐dodecaborane‐1,2‐diselena)borate, whereas the analogous reaction with boron trichloride leads mainly to 1,2‐bis(ethylseleno)‐1,2‐dicarba‐ closo ‐dodecaborane(12) through ether cleavage. The spirocyclic borate reacts with methanol by cleavage of both Se–B and Se–C bonds. With borane in THF (BH 3 /THF) and also with LiBH 4 exchange reactions take place, which afford the 1,2‐dicarba‐ closo ‐dodecaborane‐1,2‐diselenadihydroborate. The molecular structures of both borates as tetrabutylammonium salts were determined by X‐ray analysis. In solution, the borates were characterized by multinuclear magnetic resonance spectroscopy ( 1 H, 11 B, 13 C, 77 Se). The gas‐phase geometries of the borate anions were optimized [RB3LYP/6‐3111+G(d,p) level of theory], and the NMR spectroscopic parameters (chemical shifts and coupling constants) were calculated.