Synthesis and structural characterization of chromium(III) complexes containing hydrotris(1-pyrazolyl)borate

The syntheses and structural characterization of several chromium(III) complexes containing hydrotris(1-pyrazolyl)borate ligands are reported. The reaction of Cr-2(OAc)(4)(H2O)(2) with two equivalents of KTp (Tp = hydrotris(1-pyrazolyl)borate) in diglyme produced a red product that is proposed to be Cr-2(OAc)(2)Tp(2)(H2O)(2), This red product reacted with (CH3)(3)SiCl in CH2Cl2 to yield the green complex [Cr(Tp)(2)][CrCl3(Tp)] (1). The complex CrCl2(Tp)(THF) (2) was prepared by reaction of Cr-2(OAc)(4)(H2O)(2) with (CH3)(3)SiCl, followed by addition of two equivalents of KTp in THF. Reactions of 2 with PMe3 in CH2Cl2 gave [HPMe3][CrCl3(Tp)] (3). Crystal data for 1: spare group P2(1)/n, a = 12.081(1), b = 21.952(2), c = 14.123(1) Angstrom, beta = 98.06(5)degrees, V = 3708.5(4) Angstrom(3), Z = 4, with final residuals R = 0.0501 and Rw = 0.0513. Crystal data for 2: space group P2(1)/n, a = 10.051(2), b = 12.442(2), c = 14.349(2) Angstrom, beta = 98.99(2)degrees, V = 1772.4(6) Angstrom(3), Z = 4, with final residuals R = 0.0648 and Rw = 0.0672. Crystal data for 3: space group P (1) over bar, a = 9.229(2), b = 14.870(3), c = 15.049(3) Angstrom, alpha = 83.45(1), beta = 88.77(1), gamma = 75.88(1)degrees, V = 1989.6(9) Angstrom(3), Z = 4, with final residuals R = 0.0856 and Rw = 0.0865, The structure of [Cr(Tp)(2)][CrCl4] is also discussed. (C) 1998 Elsevier Science S.A.