The ethylene adducts of copper(I) tris(pyrazolyl)borates, [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu(C 2 H 4 ), ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ), and [HB(3-(CF 3 )Pz) 3 ]Cu(C 2 H 4 ), have been prepared by reacting the corresponding sodium derivative with CF 3 SO 3 Cu in the presence of ethylene. They were characterized both in the solid state and in solution using 1 H, 13 C, and 19 F NMR and IR spectroscopy and by X-ray crystallography. Solid samples of these nonionic copper complexes featuring fluorinated tris(pyrazolyl)borate ligands display notably high stability toward air oxidation and ethylene loss. The 1 H NMR chemical shifts of the copper(I)-bonded ethylene protons appear in the 4.8-5.2 ppm region. The 13 C signal of copper-coordinated ethylene shows an upfield shift of about 35 ppm, whereas the 1 J C-H shows a minor change (an increase of about 2-5 Hz) compared to the values for free ethylene. X-ray structural data show the presence of pseudo-tetrahedral copper ions and η 2 -bonded ethylene units and relatively unperturbed ethylene C-C distances. The copper adducts [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu-(C 2 H 4 ) and [HB(3-(CF 3 ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ) are competent aziridination catalysts, readily converting a variety of olefins into the corresponding N-tosyl aziridines with N-tosyl phenyliodinane.

The fluorinated tris(pyrazolyl)borate ligands [HB(3,5-(CF(3))(2)Pz)(3)](-) and [HB(3-(CF(3))Pz)(3)](-) (where Pz = pyrazolyl) have been synthesized as their sodium salts from the corresponding pyrazoles and NaBH(4) in high yield. These sodium complexes and the related [HB(3,5-(CF(3))(2)Pz)(3)]K(DMAC) were used as ligand transfer agents in the preparation of the copper and silver complexes [HB(3,5-(CF(3))(2)Pz)(3)]Cu(DMAC), [HB(3,5-(CF(3))(2)Pz)(3)]CuPPh(3), [HB(3,5-(CF(3))(2)Pz)(3)]AgPPh(3), and [HB(3-(CF(3))Pz)(3)]AgPPh(3). Metal complexes of the fluorinated [HB(3,5-(CF(3))(2)Pz)(3)](-) ligand have highly electrophilic metal sites relative to their hydrocarbon analogs. This is evident from the formation of stable adducts with neutral oxygen donors such as H(2)O, dimethylacetamide, or thf. Furthermore, the metal compounds derived from fluorinated ligands show fairly long-range coupling between fluorines of the trifluoromethyl groups and the hydrogen, silver, or phosphorus. The solid state structures show that the fluorines are in close proximity to these nuclei, thus suggesting a possible through-space coupling mechanism. Crystal structures of the sodium adducts exhibit significant metal-fluorine interactions. The treatment of [HB(3,5-(CF(3))(2)Pz)(3)]Na(H(2)O) with Et(4)NBr led to [Et(4)N][HB(3,5-(CF(3))(2)Pz)(3)], which contains a well-separated [Et(4)N](+) cation and the [HB(3,5-(CF(3))(2)Pz)(3)](-) anion in the solid state. Crystal data with Mo Kalpha (lambda = 0.710 73 Å) at 193 K: [HB(3,5-(CF(3))(2)Pz)(3)]Na(H(2)O), C(15)H(6)BF(18)N(6)NaO, a = 7.992(2) Å, b = 15.049(2) Å, c = 9.934(2) Å, beta = 101.16(2) degrees, monoclinic, P2(1)/m, Z = 2; [{HB(3-(CF(3))Pz)(3)}Na(thf)](2), C(32)H(30)B(2)F(18)N(12)Na(2)O(2), a = 9.063(3) Å, b = 10.183(2) Å, c = 12.129(2) Å, alpha = 94.61(1) degrees, beta = 101.16(2) degrees, gamma = 95.66(2) degrees, triclinic, &Pmacr;1, Z = 1; [HB(3,5-(CF(3))(2)Pz)(3)]Cu(DMAC), C(19)H(13)BCuF(18)N(7)O, a = 15.124(4) Å, b = 8.833(2) Å, c = 21.637(6) Å, beta = 105.291(14) degrees, monoclinic, P2(1)/n, Z = 4; [HB(3,5-(CF(3))(2)Pz)(3)]CuPPh(3), C(33)H(19)BCuF(18)N(6)P, a = 9.1671(8) Å, b = 14.908(2) Å, c = 26.764(3) Å, beta = 94.891(1) degrees, monoclinic, P2(1)/c, Z = 4; [HB(3,5-(CF(3))(2)Pz)(3)]AgPPh(3).0.5C(6)H(14), C(36)H(26)AgBF(18)N(6)P, a = 13.929(2) Å, b = 16.498(2) Å, c = 18.752(2) Å, beta = 111.439(6) degrees, monoclinic, P2(1)/c, Z = 4; [Et(4)N][HB(3,5-(CF(3))(2)Pz)(3)], C(23)H(24)BF(18)N(7), a = 10.155(2) Å, b = 18.580(4) Å, c = 16.875(5) Å, beta = 99.01(2) degrees, monoclinic, P2(1)/n, Z = 4.

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)Pz)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 1H, 13C, and 19F 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 υCO values, but they are notably lower than the corresponding υCO values of the 3,5-disubstituted analog [HB(3,5-(CF3)2Pz)3]CuCO.