Zinc Pyrazolylborate Complexes with Phenoxide and Alkoxide Ligands

The zinc hydroxide complexes Tp*Zn‐OH of highly substituted pyrazolylborate ligands react with phenols, and alcohols, of sufficient acidity, in a condensation reaction with release of H2O. Starting with phenols the following were attached:phenolate, p‐nitropehnolate, o‐vanillinate, o‐hydroxymethylphenolate, o,o‐bis(hydroxymethyl) ‐p‐methylphenolate. Whilst aliphatic alcohols and benzyl alcohol did not react, their derivatives, with highly electronegative substituents could be incorporated. Thus, the arylmethoxides OCH2C6F5 and OCH2C6H4NO2‐p, as well as the alkoxides OCH2CF3 and OCH2CCl3, were attached. 2‐Mercaptoethanol was bound via its thiolate function. The crystal structures of TpCum,Me ZN‐OC6H4NO2‐p,TpCum,Me ZN‐OCH2‐C6F5, TpCum,Me ZN‐OCH2CF3, TpCum,Me ZN‐OCH2CCl3 and TpCum,MeZn‐SCH2CH2OH were determined.