Pentamethylcyclopentadienylrhodaborane chemistry. Part 3. The reaction of [{Rh(η5-C5Me5)Cl2}2] with closo-[B10H10]2–and arachno-B10H12-6,9-(PMe2Ph)2, and the characterisation of some novel rhodaboranes by X-ray diffraction analysis and nuclear magnetic resonance spectroscopy

Publisher Website
Google Scholar
Abstract
Reaction of the rhodaborane synthon [{Rh(η5-C5Me5)Cl2}2] with closo-[B10H10]2–- in dichloromethane solution results in the rapid insertion, in reasonable yield, of a Rh(η5-C5Me5) vertex to give orange, air-stable crystals of [1-(η5-C5Me5)-closo-1-RhB10H10](1). When methanol is also present the major product (40% yield) is the related orange, air-stable, methoxy derivative [1-(η5-C5Me5)-closo-1-RhB10H9-2-(OMe)](2). X-Ray diffraction analysis of (2) established a triclinic unit cell, space group P, with a= 1 407.7(2), b= 878.9(1), c= 835.9(2) pm, α= 111.19(1), β= 103.44(1),γ= 92.24(1)°, and Z= 2. Detailed n.m.r. data on (1) and (2) are also discussed. Reaction of [{Rh(η5-C5Me5)Cl2}2] with the bis-ligand adduct arachno-B10H12-6,9-(PMe2Ph)2 affords yellow, air-stable crystals of the dichloromethane solvate [7-(η5-C5Me5)-nido-7-RhB10H11-8-Cl-11-(PMe2Ph)]·CH2Cl2(3)[monoclinic, space group P21/n, with a= 1 520.4(2), b= 1 228.3(3), c= 1 622.3(2) pm, β= 102.24(1)°, and Z= 4]. A notable feature of the structure is the presence of three bridging H atoms in the five-atom RhB4 open face of the nido cluster. Two-dimensional [11B–11B]-COSY,[1H–1H]{11B}-COSY, and 1H-{11B(selective)} n.m.r. experiments revealed further interesting features of this cluster species. Treatment of (3) with an excess of the ligand PMe2Ph in the presence of H2O or O2 gave a 63% yield of the novel twelve-vertex nido-rhodaoxaborane [7-(η5-C5Me5)-nido-7,12-RhOB10H9-8-Cl-11-(PMe2Ph)](4). Orange-red, air-stable crystals of (4) were monoclinic, space group P21/n, with a= 867.7(2), b= 1 984.4(4), c= 1 551.8(3) pm, β= 102.08(2)°, and Z= 4. The cluster structure of (4) is closely related to that of (3) but with the unique oxygen atom replacing two bridging hydrogens in the open face. Detailed n.m.r. data are also presented and discussed.

This publication has 0 references indexed in Scilit: