Polyfluoroalkoxyaluminates and borates as new weakly coordinating anions and as components of battery electrolytes.

摘要

The synthesis and characterization of salts of new weakly coordinating anions based on the general formulas B(O₂L_f)₂ − and Al(OR_f)₄− are reported. New B(O₂L_f)₂− anions are B(OC(2-C₆H₄O)(CF₃)₂) ₂−, B(OC(2-(O)-3-C₆H₃F)(CF ₃)₂)₂−, B(OC(2-(O)-4-C ₆H₃F)(CF₃)₂)₂− , B(OC(2-(O)-5-C₆H₃F)(CF₃)₂ )₂−, B(OC(2-(O)-3,5-C₆H ₂F₂)(CF₃)₂)₂− , B(OC(2-(O)-4,5-C₆H₂F₂)(CF ₃)₂)₂−, B(OC(2-(O)-4,6-C ₆H₂F₂)(CF₃)₂)₂ −, B(OC(2-(O)-3,4,5-C₆HF₃)(CF₃) ₂)₂−, B(OC(2-(O)-4,5,6-C₆HF ₃)(CF₃)₂)₂−, B(OC(2-(O)-3- t-Bu-5-Me-C₆H₂)(CF₃)₂) ₂−, B(OC(2-(O)-3,5-C₆H₂( t-Bu)₂)(CF₃)₂)₂ −, B(OC(2-(O)-3-C₆H₃I)(CF₃) ₂)₂−. Except for HOC(2-C₆H ₄(OH))(CF₃)₂, HOC(2-(OH)-4-C₆H ₃F)(CF₃)₂, and HOC(2-(OH)-3,5-C₆H ₂(t-Bu)₂)(CF₃)₂, all of the diols used as ligand precursors in the new borate anions are new compounds. The new LiAl(OR_f)₄ salts prepared are LiAl(OCH(CF ₃)₂)₄, LiAl(OC(cyclo-C₆ H₁₁)(CF₃)₂)₄, and LiAl(OC(C ₆H₅)(CF₃)₂)₄. Four Li + salts of the new borates and aluminates were structurally characterized by X-ray crystallography: Li(OC(CH₃)₂)(B(OC(2-(O)-3,4,5-C ₆HF₃)(CF₃)₂)₂, Li₂ (CH₃O(CH₂)₂OCH₃)(B(OC(2-C ₆H₄O)(CF₃)₂)₂), LiAl(OCH(CF ₃)₂)₄, and LiAl(OC(cyclo-C ₆H₁₁)(CF₃)₂)₄.; Conductivities of solutions of many of the new salts were determined for the solvents in various solvents. Conductivities were also measured for the first time for the known salts LiAl(OC(CH₃)(CF₃) ₂)₄, LiAl(OCH(C₆H₅)(CF₃) ₂)₄, LiAl(OC(4-C₆H₄(CH₃)(CF ₃)₂)₄, LiAl(OC(4-C₆H₄( t-Bu))(CF₃)₂)₄, LiAl(OC(C₆ H₅)(CF₃)₂)₄, and LiAl(OC(CF ₃)₃)₄. Based on these measurements, it was determined that all of the anions are more weakly coordinating and more weakly ion-pairing than the commonly-used weakly coordinating anion CF₃SO₃ −. For the B(O₂L_f)₂ − anions, it was found that the ion-pairing strength depends not only on the number of fluorine atoms incorpor