Salts of the bis(catecholato)borate anion with rhodium- and iridium-phosphine complex cations

William Clegg, Mark R.J. Elsegood, Andrew J. Scott, Todd B. Marder, Chaoyang Dai, Nicholas C. Norman, Nigel L. Pickett, Edward G. Robins

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In a series of five salts with rhodium- or iridium-phosphine complex cations {cis-chlorohydridotetrakis-(triethylphosphine)iridium(III) bis(pyrocatecholato-O,O′)borate, [IrClH(C6H15P)4](C12H 8BO4), (1); transchlorobis[ethylenebis(diphenylphosphine)]hydridorhodium(III) bis(pyrocatecholato-O,O′)borate dichloromethane solvate, [RhClH(C26H24P2)2](C 12H8BO4)·CH2-Cl2, (2); trans-chlorobis[ethylenebis(dicyclohexylphosphine)]hydridorhodium(III) bis(pyrocatecholato-O,O′)-borate tetrakis(dichloromethane) solvate, [RhClH(C26-H48P2)2](C 12H8BO4)·4CH2Cl2, (3); tetrakis(trimethylphosphine)rhodium(I) bis(pyrocatecholato-O,O′)borate, [Rh(C3H9P)4](C12H8BO 4), (4); and cis-dihydridotetrakis-(trimethylphosphine)rhodium(III) bis(pyrocatecholato-O,O′)borate, [RhH2(C3H9P)4](C12H 8BO4), (5)}, the bis-(catecholato)borate anion has approximate D2d (4̄2m) symmetry, with the central spiro-B atom distorted from regular tetrahedral coordination geometry by reduction of the two intra-ring O - B - O bond angles. The two chelate rings show small deviations from planarity by folding about the O⋯O axis. The hydrido and chloro ligands in the cation of compound (1), which has four monodentate phosphine ligands, are cis to each other, but in compounds (2) and (3), each with two chelating diphosphine ligands, they are mutually trans. The cation in compound (4) has only four phosphine ligands, which are arranged in a tetragonally distorted square-planar arrangement to minimise steric crowding. Its reaction product with molecular dihydrogen, compound (5), has a cis arrangement of the two hydrido ligands in a distorted octahedral cation. The strong trans influence of the hydrido ligands is reflected in lengthened bonds to the opposite ligands in each case.

Original languageEnglish
Pages (from-to)733-739
Number of pages7
JournalActa Crystallographica Section C: Crystal Structure Communications
Issue number5
Publication statusPublished or Issued - 15 May 1999
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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