Three nido 11-vertex platinaundecaborane clusters: [(PPh₃)₂PtB₁₀H₁₁-9-O-i-Pr] (1), [(PPh₃)₂PtB₁₀H₁₀-8,10-(O-i-Pr)₂] (2) and [(PPh₃)₂PtB₁₀H₁₁-8-O-i-Pr] (3) were obtained from the reaction of [PtCl₂(PPh₃)₂] with (Et₄N)₂B₁₀H₁₀ in i-PrOH under reflux conditions. They all have a nido 11-vertex PtB₁₀ polyhedral skeleton, in which Pt atom lies on the open PtB₄ face. Each Pt atom was connected with four B atoms and two P atoms of PPh₃ ligand. Two novel B₁₀H₁₀^2－ deboronated nido 11-vertex diplatinaundecaboranes: [(PPh₃)₂(μ-PPh₂)Pt₂B₉H₆-3,9,11-(O-i-Pr)₃] (4) and [(PPh₃)₂(μ-PPh₂)Pt₂B₉H₆-3,9-(O-i-Pr)₂-11-Cl] (5) were obtained when the same reaction was carried out under solvothermal conditions. Cluster compounds 4 and 5 have a nido 11-vertex Pt₂B₉ polyhedral skeleton, in which two Pt atoms stay at neighbouring positions of the open Pt₂B₃ face and bridged by a PPh₂ ligand. Each Pt atom was connected with three B atoms and a P atom of PPh₃ ligand. They were characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction.

Key words: nido configuration, platinaborane, cluster, solvothermal synthesis, crystal structure