Novel tris(pyrazolyl)borates bearing perfluoroalkyl pigtails. Syntheses and characterization of the sodium and copper(I) complexes of [HB(3-(R)Pz)(3)](-) (R=C2F5, C3F7; Pz=pyrazolyl)

3-(Pentafluoroethyl)pyrazole and 3-(heptafluoropropyl)pyrazole were synthesized and fully characterized. These pyrazoles react with NaBH4 to yield sodium salts of [HB(3-(C2F5)-Pz)(3)](-) and [HB(3-(C3F7)Pz)(3)](-). The X-ray crystal structure of [HB(3-(C2F5)Pz)(3)]Na(3-(C2F5)-PzH) shows close contacts between the sodium atom and fluorine atoms of the -C2F5 substituents. The copper-carbon monoxide adducts [HB(3-(C2F5)zP)(3)]CuCO and [HB(3-(C3F7)Pz)(3)]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 H-1, C-13, and F-19 NMR and IR spectroscopies. IR spectroscopic data of [HB(3-(CF3)Pz)(3)]-CuCO, [HB(3-(C2F5)Pz)(3)]CuCO, and [HB(3-(C3F7)Pz)(3)]CuCO did not exhibit a significant difference in the vco values, but they are notably lower than the corresponding v(CO) values of the 3,5-disubstituted analog [HB(3,5-(CF3)(2)Pz)(3)]CuCO.