| The synthesis and characterization of salts of new weakly coordinating anions based on the general formulas B(O2Lf)2 − and Al(ORf)4− are reported. New B(O2Lf)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(ORf)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(O2Lf)2 − anions, it was found that the ion-pairing strength depends not only on the number of fluorine atoms incorpor... |
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