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 NaBH 4 to yield sodium salts of [HB(3-(C 2 F 5 )Pz) 3 ] - and [HB(3-(C 3 F 7 )Pz) 3 ] - . The X-ray crystal structure of [HB(3-(C 2 F 5 )Pz) 3 ]Na(3-(C 2 F 5 )PzH) shows close contacts between the sodium atom and fluorine atoms of the −C 2 F 5 substituents. The copper−carbon monoxide adducts [HB(3-(C 2 F 5 )Pz) 3 ]CuCO and [HB(3-(C 3 F 7 )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 1 H, 13 C, and 19 F NMR and IR spectroscopies. IR spectroscopic data of [HB(3-(CF 3 )Pz) 3 ]CuCO, [HB(3-(C 2 F 5 )Pz) 3 ]CuCO, and [HB(3-(C 3 F 7 )Pz) 3 ]CuCO did not exhibit a significant difference in the υ CO values, but they are notably lower than the corresponding υ CO values of the 3,5-disubstituted analog [HB(3,5-(CF 3 ) 2 Pz) 3 ]CuCO.