Synthesis and coordination chemistry of TpC*MI complexes where M = Mg, Ca, Sr, Ba and Zn and TpC* = tris[3-(2-methoxy-1,1-dimethyl)pyrazolyl]hydroborate

Abstract

Reactions involving MI₂ where M = Mg, Ca, Sr, Ba or Zn and M′Tp^C* where M′ = Na or Tl and Tp^C* = tris[3-methoxy-1,1-dimethyl)pyrazolyl]hydroborate in tetrahydrofuran are described leading to the isolation and characterization of the complexes Tp^C*MgI, I, Tp^C*CaI, II, Tp^C*SrI, III, Tp^C*SrI(THF), IV, Tp^C*BaI, V, Tp^C*BaI(pz*H), VI, where pz*H = 3-(2-methoxyl-1,1-dimethyl)pyrazole, Tp^C*BaI·½toluene, VII and Tp^C*ZnI, VIII. The compounds I, II, IV, VI, VII and VIII have been characterized by single-crystal X-ray crystallography. Compounds I and II are isostructural and are salt-like containing κ⁶-TpM⁺ cations and I⁻ anions. In all other structures, the iodide is bound to the metal and Tp^C* is κ⁶ bonded to the group 2 M(2+) ions. Reactions involving Tp^C*CaI, II, and sodium or lithium alkoxides or amides failed to yield the amide or alkoxide calcium Tp^C* derivative, though related reactions involving Tp^C*ZnI, VIII, and KOSiMe₃ proceeded quantitatively to yield κ³Tp^C*ZnOSiMe₃, IX, which was also structurally characterized and shown to have the κ³-Tp^C* bound ligand.