Ruthenium(II) complexes of closo-dodecaboranyl anions and the molecular structure of the pileo thirteen-vertex ruthenaborane [(PPh3)2ClRuB12H11(NEt3)

Abstract

Reaction of Na2[closo-B12H12] with [RuCl3(PMe2Ph)3] gives a 10% yield of the lemon-yellow air-stable covalent complex [(PMe2Ph)3RuB12H12], characterized by elemental analysis and multielement nuclear magnetic single- and multiple-resonance spectroscopy. Reaction of [NHEt3]2[B12H12] and [RuCl2(PPh3)3] results in the formation of [(PPh3)2ClRuB12H11(NEt3)] as an orange-red air-stable compound (30%), characterized by single-crystal X-ray diffraction analysis as well as n.m.r. spectroscopy. The solvate [(PPh3)2ClRuB12H11(NEt3)]·CH2Cl2 forms monoclinic crystals, with a= 2 246.3(2), b= 1 189.2(2), c= 1 972.5(2) pm, β= 111.04(1)°, Z= 4, and space group P21/n. The compounds may formally be regarded either as ruthenium(II) complexes of closo-dodecaboranyl ligands which bind in a trihapto tridentate mode to the octahedral metal centres via three two-electron three-centre B–H–Ru bridge bonds, or as 13-vertex pileo 2n-electron metallaborane cluster species which have capped closed deltahedral cluster geometries.