Novel Tris(pyrazolyl)borates Bearing Perfluoroalkyl Pigtails. Syntheses and Characterization of the Sodium and Copper(I) Complexes of [HB(3-(R)Pz)<INF>3</INF>]<SUP>-</SUP> (R = C<INF>2</INF>F<INF>5</INF>, C<INF>3</INF>F<INF>7</INF>; Pz = Pyrazolyl)

3-(Pentafluoroethyl)pyrazole and 3-(heptafluoropropyl)pyrazole were synthesized and fully characterized. These pyrazoles react with NaBH<INF>4</INF> to yield sodium salts of [HB(3-(C<INF>2</INF>F<INF>5</INF>)Pz)<INF>3</INF>]^- and [HB(3-(C<INF>3</INF>F<INF>7</INF>)Pz)<INF>3</INF>]^-. The X-ray crystal structure of [HB(3-(C<INF>2</INF>F<INF>5</INF>)Pz)<INF>3</INF>]Na(3-(C<INF>2</INF>F<INF>5</INF>)PzH) shows close contacts between the sodium atom and fluorine atoms of the −C<INF>2</INF>F<INF>5</INF> substituents. The copper−carbon monoxide adducts [HB(3-(C<INF>2</INF>F<INF>5</INF>)Pz)<INF>3</INF>]CuCO and [HB(3-(C<INF>3</INF>F<INF>7</INF>)Pz)<INF>3</INF>]CuCO were prepared by the treatment of CuOTf with 1 equiv of the corresponding tris(pyrazolyl)boratosodium under CO. The copper and sodium complexes were characterized by ¹H, ¹³C, and ¹⁹F NMR and IR spectroscopies. IR spectroscopic data of [HB(3-(CF<INF>3</INF>)Pz)<INF>3</INF>]CuCO, [HB(3-(C<INF>2</INF>F<INF>5</INF>)Pz)<INF>3</INF>]CuCO, and [HB(3-(C<INF>3</INF>F<INF>7</INF>)Pz)<INF>3</INF>]CuCO did not exhibit a significant difference in the υ<INF>CO</INF> values, but they are notably lower than the corresponding υ<INF>CO</INF> values of the 3,5-disubstituted analog [HB(3,5-(CF<INF>3</INF>)<INF>2</INF>Pz)<INF>3</INF>]CuCO.