Novel complexes of rhodium(I) [Rh(diolefin)(Q?)] (where HQ?=1-phenyl-3-methyl-4-acetylpyrazol-5-one and diolefin=cycloocta-1,5-diene (COD), bicyclo[2.2.1]hepta-2,5-diene (NBD) or 1,5-hexadiene (HEX)) were synthesized and characterized by analytical and spectral data. [Rh(COD)(Q?)] interacts with 4,5-dimethyl-1,10-phenanthroline (Me2Phen) and 2,2?-bipyridil (Bipy) yielding the cationic derivatives [Rh(COD)(Me2Phen)](Q?)(H2O), [Rh(COD)(Bipy)](Q?)(H2O) upon displacement of the (Q?)- donor from the coordination sphere of the metal center. Whereas [Rh(COD)(Q?)] interacts with 2-benzoylpyridine (Bzpy) yielding the 1:1 adduct [Rh(COD)(Bzpy)(Q?)] in which Bzpy acts as N-monodentate donor. On the other hand the monodentate P-donors triphenylphosphine, triphenylphosphite, tricyclohexylphosphine and the bidentate bis(diphenylphosphino)ethane (DPPE) displace the COD ligand from [Rh(COD)(Q?)] giving the neutral derivatives [Rh(PR3)2(Q?)] (PR3=PPh3, or P(OPh)3) and [Rh(DPPE)(Q?)](H2O). HQ? reacts with the dinuclear [Rh(CO)2Cl]2. The tetradentate cycloocto-tetraene (COT) reacts with [Rh(CO)2(Q?)] yielding the derivative [Rh(CO)2(HQ?)Cl] in which HQ? acts as neutral monodentate O-donor ligand. Whereas in presence of NEt3 HQ? reacts with [Rh(CO)2Cl]2 yielding [Rh(CO)2(Q?)]. In this complex, one molecule of CO can be replaced by one mole of Phen and Bipy or by two moles of PPh3 and AsPh3 yielding the derivatives [Rh(CO)(L)n(Q?)]·x(H2O) (L=Me2Phen or Bipy, n=1; L=PPh3 or AsPh3, n=2) whereas one mole of DPPE displaces both the molecules of CO, yielding [Rh(DPPE)(Q?)] yielding the derivative [Rh(COT)(Q?)]. The X-ray crystal structure determination of [Rh(COD)(Q?)] establishes that the rhodium atom is in a square planar configuration with two adjacent sites occupied by the (Q?)- ligand in the O2-bidentate form (Rh-O distances=2.054(2) and 2.061(2) Å). The COD ring has a twisted boat conformation with Rh-C distances in the range 2.101(3)-2.110(3) Å. Comparison was made with structural data reported for several related tetracoordinated (COD)Rh(I) adducts.

(1-Phenyl-3-methyl-4-acetylpyrazolon-5-ato)rhodium(I) complexes, synthesis, structural and spectroscopical characterization: Reactivity of diolefin- and dicarbonyl-rhodium complexes toward N-, P- and O-donors

L Barba b
1998

Abstract

Novel complexes of rhodium(I) [Rh(diolefin)(Q?)] (where HQ?=1-phenyl-3-methyl-4-acetylpyrazol-5-one and diolefin=cycloocta-1,5-diene (COD), bicyclo[2.2.1]hepta-2,5-diene (NBD) or 1,5-hexadiene (HEX)) were synthesized and characterized by analytical and spectral data. [Rh(COD)(Q?)] interacts with 4,5-dimethyl-1,10-phenanthroline (Me2Phen) and 2,2?-bipyridil (Bipy) yielding the cationic derivatives [Rh(COD)(Me2Phen)](Q?)(H2O), [Rh(COD)(Bipy)](Q?)(H2O) upon displacement of the (Q?)- donor from the coordination sphere of the metal center. Whereas [Rh(COD)(Q?)] interacts with 2-benzoylpyridine (Bzpy) yielding the 1:1 adduct [Rh(COD)(Bzpy)(Q?)] in which Bzpy acts as N-monodentate donor. On the other hand the monodentate P-donors triphenylphosphine, triphenylphosphite, tricyclohexylphosphine and the bidentate bis(diphenylphosphino)ethane (DPPE) displace the COD ligand from [Rh(COD)(Q?)] giving the neutral derivatives [Rh(PR3)2(Q?)] (PR3=PPh3, or P(OPh)3) and [Rh(DPPE)(Q?)](H2O). HQ? reacts with the dinuclear [Rh(CO)2Cl]2. The tetradentate cycloocto-tetraene (COT) reacts with [Rh(CO)2(Q?)] yielding the derivative [Rh(CO)2(HQ?)Cl] in which HQ? acts as neutral monodentate O-donor ligand. Whereas in presence of NEt3 HQ? reacts with [Rh(CO)2Cl]2 yielding [Rh(CO)2(Q?)]. In this complex, one molecule of CO can be replaced by one mole of Phen and Bipy or by two moles of PPh3 and AsPh3 yielding the derivatives [Rh(CO)(L)n(Q?)]·x(H2O) (L=Me2Phen or Bipy, n=1; L=PPh3 or AsPh3, n=2) whereas one mole of DPPE displaces both the molecules of CO, yielding [Rh(DPPE)(Q?)] yielding the derivative [Rh(COT)(Q?)]. The X-ray crystal structure determination of [Rh(COD)(Q?)] establishes that the rhodium atom is in a square planar configuration with two adjacent sites occupied by the (Q?)- ligand in the O2-bidentate form (Rh-O distances=2.054(2) and 2.061(2) Å). The COD ring has a twisted boat conformation with Rh-C distances in the range 2.101(3)-2.110(3) Å. Comparison was made with structural data reported for several related tetracoordinated (COD)Rh(I) adducts.
1998
Istituto di Cristallografia - IC
Rhodium
Diolefin
Phenanthroline
Bipyridyl
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/16866
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