149580-68-7Relevant academic research and scientific papers
Eleven-vertex Polyhedral Monocarbaplatinaborane Chemistry. Structure and Fluxionality of
Stibr, Bohumil,Jelinek, Tomas,Kennedy, John D.,Fontaine, Xavier L. R.,Thornton-Pett, Mark
, p. 1261 - 1268 (1993)
Reaction between and arachno-6-CB9H14>(1-) in CH2Cl solution at room temperature yields yellow air-stable eleven-vetex 1 (46-64percent) together with small quantities of ten-vertex 2 (0-3percent).Crystals of compound 1 are monoclinic, space group P21/n, with a = 1186.8(1), b = 1554.1(2), c = 1344.1(2) pm, β = 95.02(1) deg and Z = 4.The structure refined to R,R'= 0.0297, 0.0310 using 3938 data with I > 3?(I).The cluster structure is of the nido eleven-vertex type, with the platinum and carbon atoms occupying adjacent positions on the open face.There is some geometrical closure from pure nido, so that the gross cluster structure tends towards intermediacy between those of 4 and of the closo-structured species 3.The NMR properties of 1 are reported and assessed for intermediacy between those of 3 and 4, and the analytical utility of NMR spectroscopy in assessing the metal-to-cluster bonding is developed by comparison with non-metallated species.The metal-to-carborane bonding sphere of compound 1 is fluxional, with ΔG(excit.)313 ca. 62 kJ mol1.The fluxional process involves and interconversion of enantiomers with the platinum centre and the bridging hydrogen atom migrating around the open face of the cage while the exo polyhedral ligand sphere undergoes a half-twist.
Polyhedral metallaheteroborane chemistry. Synthesis, spectroscopy, structure and dynamics of eleven-vertex {RhNB9} and {PtCB 9} metallaheteroboranes
Macias, Ramon,Bould, Jonathan,Holub, Josef,Kennedy, John D.,Tibr, Bohumil,Thornton-Pett, Mark
, p. 2885 - 2897 (2008/02/10)
Reaction between [RhCl(PPh3)3] and the [nido-6-NB9H11]- anion in CH2Cl 2 yields orange eleven-vertex [8,8-(PPh3) 2-nido-8,7-RhNB9H11] (1). Reaction of the [nido-6-CB9H12]- anion with [cis-PtCl 2(PMe2Ph)2] in methanol affords yellow eleven-vertex [9-(OMe)-8,8-(PMe2Ph)2-nido-8,7-PtCB 9H10] (2), which is also formed from the reaction of MeOH with [8,8-(PPh3)2-nido-8,7-PtCB9H10] (3). Both compounds have been characterised by single-crystal X-ray diffraction analysis and examined by NMR spectroscopy and have structures based on eleven-vertex nido-type geometries, with the metal centre and the heteroatoms in the adjacent (8)- and (7)-positions on the pentagonal open face. The metal-to-heteroborane bonding sphere of 1 is fluxional, with a ΔG ? value of 48.4 kJ mol-1. DFT calculations on the model compounds [8,8-(PH3)2-nido-8,7-RhNB 9H11] (1a) and [8,8-(PH3)2-nido-8,7- RhSB9H10] (4a) have been carried out to define the fluxional process and the intermediates involved. The Royal Society of Chemistry.
