New Hexazirconium Clusters Containing Hydrogen Atoms

Reduction of ZrBr₄ with HSnBu₃ yielded a blue solid. When this blue solid was treated with PMe₃, a hexanuelear cluster Zr₆Br₁₄H₄( PMe₃)₄] (2) was isolated. Reaction of the blue solid with PPh₄]Br in CH₂Cl₂ resulted in the formation of a paramagnetic and unstable cluster anion, Zr₆Br₁₈H₅]^2– (3), which disproportionated to form a new cluster anion, Zr₆Br₁₈H₅]^3– (4) and some Zr(IV) species. Compounds containing 4 can also be obtained from reaction of the blue solid with Br^– in MeCN. Reduction of ZrCl₄ with HsnBu₃ gave a red–brown solid, and Zr₆Cl₁₄H₄(AsMe₃)₄] (9) and Zr₅Cl₁₂H₄(AsMe₃)₅](8) were obtained by reaction of the red–brown solid with AsMe₃. No cluster compounds containing amine ligands were obtained in the reaction of the red–brown solid with amines; only compounds containing the Zr₆Cl₁₈ H₅]^3– anion and ammonium cations were isolated. Altogether ten products were characterized by single crystal X-ray diffraction and where possible, by ¹H NMR studies.