Titanate(1-) complexes Na[(THF)(kappa(1)-O-bdbpzp)TiCl4] (1) and Na[(THF)(kappa(1)-O-bdmpzp)TiCl4] (2) and titanate(2-) complexes [Na(THF)](2)[(K-1-O-bdbpzp)(2)TiCl4] (4) and [Na(THF)](2)[(kappa(1)-O-bdMPZP)(2)TiCl4] (5) were obtained in good yield from reaction of Na[bdbpzp] or Na[bdmpzp] (sodium salt of 1,3-bis(3,5-di-te -butylpyrazol-lyl)propan-2-ol or 1,3-bis(3,5-dimethylpyrazol-1yl)propan-2-ol) with TiCl4 (in the appropriate molar ratio) at 0-25 degrees C. Protonolysis of TiCl4 with 1 equiv of bdmpzpH furnished related zwitterionic titanate(1-) complex 3 that possessed a kappa(2)-N,O-coordinated pyrazolyi-alkoxide with pendant pyrazolium group. Methylalurnoxane (MAO) activation of 1-5 under high-temperature solution polymerization conditions produced active single-site ethylene polymerization catalysts that exhibit considerably higher thermal stability (especially 2/MAO, 3/MAO, and 5/MAO) than previously reported for CP2TiCl2/MAO or Ti catalysts supported by related heteroscorpionate or scorpionate ligation.