SIMPLE ZINC-COMPLEXES OF PYRIDYL-SUBSTITUTED TRIS(PYRAZOLYL)BORATE LIGANDS

Treatment of the potassium salts of the Tp(x) ligands hydrotris(5-meth yl-3-py-pyrazolyl)borate Tp(3Py,Me) (py* = 3-pyridyl) and Tp(Pic,Me) (py 5-alpha-picolyl) with zinc halides or with Zn(ClO4)(2) and KOH yi elds the halide complexes Tp(3Py,Me)Zn-Hal (Hal = F, Cl, Br, I) and th e hydroxide complexes Tp(3Py,Me)Zn-OH and Tp(Pic,Me)Zn-OH, as well as the bis(ligand) complex (Tp(3Py,Me))(2)Zn. AU Tp(3Py,Me)Zn-X complexes show a tendency for dimerization, using one pyridyl group each of the two Tp(3Py,Me) units to coordinate to the zinc ion of the opposite Tp (3Py,Me)Zn fragment, as evidenced by the solid state structures of Tp( 3Py,Me)Zn-F (strong interaction) and Tp(3Py,Me) Zn-I (weak interaction ) and by a variable-temperature NMR. study of Tp(3Py,Me)Zn-OH. Despite the steric bulk of the Tp(3Py,Me) ligands, the his(ligand) complex (T p(3Py,Me))(2)Zn contains zinc bound to all pyrazole nitrogen donor ato ms in an octahedral fashion. Tp(3Py,Me)Zn-F crystallizes in the tricli nic space group <P(1)over bar> with a = 11.123(5) Angstrom, b = 11.638 (7) Angstrom, c = 13.793(4) Angstrom, alpha = 72.34(3)degrees, beta = 75.32(3)degrees, gamma = 73.09(5)degrees, and Z = 2. Tp(3py,Me)Zn-I cr ystallizes in the monoclinic space group C2/c with a = 18.922(1) Angst rom, b = 10.476(4) Angstrom, c = 31.444(1) Angstrom, beta = 101.99(4)d egrees, and Z = 8. (Tp(3Py,Me))(2)Zn crystallizes in the monoclinic sp ace group C2/c with a = 18.330(2) Angstrom, b = 13.876(1) Angstrom, c = 21.616(1) Angstrom, beta = 115.96(7)degrees, and Z = 4.