INDIUM(III) COMPLEXES OF POTENTIALLY TRIDENTATE POLY(PYRAZOLYL)BORATELIGANDS - IONIZATION OF MOLECULAR [HB(PZ)3]2INCL IN CD2CL2 SOLUTION

The reaction of 3 equiv of [B(pz)4]- with InCl3 in either THF or THF/H 2O results in the formation of [B(PZ)4]3In. The reaction of 2 equiv of [B(PZ)4]- with InCl3 in THF results in the formation of [B(PZ)4]2InCl . Variable-temperature NMR studies indicate that the latter complex ha s an octahedral structure with one bidentate and one tridentate ligand . An analogous reaction using InCH3Cl2 yields [B(pz)4]2InCH3, a comple x shown crystallographically to have an octahedral structure with one bidentate and one tridentate ligand. The reaction of [B(PZ)4]- with In (CH3)2Cl yields [B(pz)4]In(CH3)2, a complex believed to have a four-co ordinate structure. The six-coordinate complexes [HB(PZ)3]InCl2.THF an d [HB(pz)3]2InCl form in the reaction with InCl3 of 1 and 2 equiv of [ HB(PZ)3]-, respectively. Low-temperature NMR studies in the nonpolar s olvent toluene-d8 indicate that [HB(PZ)3]2InCl has a six-coordinate st ructure with one bidentate and one tridentate ligand. In CD2Cl2, the c hloride ligand ionizes yielding a solution of the ionic compound {[HB( PZ)3]2In}Cl. Dissolving [HB(pz)3]2InCl in CDCl3 or a 1/1 mixture of CD 2Cl2/toluene-d8 yields solutions containing both the ionic and covalen t forms. The cation {[HB(pz)3]2In}+ can also be prepared from a number of other routes, including the reaction of 1 equiv of [HB(pz)3]- and InCl3 in a THF/H2O solvent system to yield {[HB(PZ)3]2In}{InCl4}. The reaction of 3 equiv of [HB(pz)3]- with 2 equiv of InCl3 in a mixed THF /H2O solvent system yields {[HB(pz)3]2In}{[HB(pz)3]InCl3}, as characte rized by X-ray crystallography. The reaction of In(CH3)Cl2 with 2 equi v of [HB(pz)3]- leads to the formation of [HB(pz)3]2InCH3, another exa mple of a complex believed to have a six-coordinate structure. The rea ction of either 1 or 2 equiv of [HB(3,5-Me2pz)3]- with InCl3 in THF le ads to the isolation of[HB(3,5-Me2PZ)3]InCl2.THF. [HB(3,5-Me2PZ)3]InCl 2.H(3,5-Me2pz) forms in similar reactions in toluene or in THF in the presence of added H(3,5-Me2PZ). The reaction of either 1 or 2 equiv of [HB(3,5-Me2pz)3]- with InCH3Cl2 yields [HB(3,5-Me2PZ)3]In(Cl)(CH3), a complex believed to be four coordinate. Crystal data: [B(pz)4]2lnCH3. 2tol (tol = toluene), triclinic, P1BAR, a = 8.637(4) angstrom, b = 12. 549(6) angstrom, c = 18.815(10) angstrom, alpha = 104.45(4)degrees, be ta = 96.94(4)degrees, gamma = 98.09(4)degrees, V = 1929.1(16) angstrom 3, Z = 2, T = 243 K, R(F) = 10.46%; {[HB(pz)3]2In}{[HB(pz)3]InCI3}.THF .CH2Cl2, orthorhombic, Pbca, a = 18.688(8) angstrom, b = 16.584(5) ang strom, c = 29.640(12) angstrom, V = 9183.8(6) angstrom3, Z = 8, T = 23 8 K, R(F) = 5.99%.