NB(OCH(CF3)(2))(6)(-) - PROTOTYPE FOR A NEW CLASS OF WEAKLY COORDINATING ANIONS BASED ON POLYFLUOROALKOXIDE SUBSTITUENTS

The synthesis and characterization of Li+ and CPh3+ salts of the new w eakly coordinating anion Nb(OCH(CF3)(2))(6)(-) (Nb(HFIP)(6)(-)) are re ported. The lithium salt was found to be an effective catalyst in 1,2- dichloroethane for the addition of a silyl ketene acetal to a sterical ly hindered alpha,beta-unsaturated carbonyl compound. Its catalytic ac tivity and regioselectivity are similar to those of LiCo(C2B9H11)(2) a nd are far superior to those of LiClO4. The lithium salt was also used to prepare salt-in-polymer electrolytes using amorphous polyethylene oxide (aPEO). Three new electrolytes were prepared: aPEO(12)LiNb(HFIP) (6), aPEO(24)LiNb(HFIP)(6) and aPEO(30)LiNb(HFIP)(6). Their glass tran sition temperatures were found to be 227, 222 and 219 K, respectively. Their 293 K d.c. conductivities were found to be 1.4 x 10(-5), 1.0 x 10(-4) and 5.0 x 10(-5) S cm(-1), respectively. (C) 1997 Elsevier Scie nce S.A.