Novel [Ru(η 6-p-cymene)(κ 2-L)X] and [Ru(η 6-p-cymene)(κ 3-L)]X•nH 2O complexes (L = bis-, tris-, or tetrakis-pyrazolylborate; X = Cl, N 3, PF 6, or CF 3SO 3) are prepared by treatment of [Ru(η 6-p-cymene)Cl 2] 2 with poly(pyrazolyl)borate derivatives [M(L)] (L in general; in detail L = Ph 2Bp = diphenylbis(pyrazol-1-yl)borate; L = Tp = hydrotris(pyrazol-1- yl)borate; L = pzTp = tetrakis(pyrazol-1-yl)borate; L = Tp 4Bo = hydrotris(indazol-1-yl)borate, L = Tp 4Bo,5Me = hydrotris(5- methylindazol-1-yl)borate; L = Tp Bn,4Ph = hydrotris(3-benzyl-4- phenylpyrazol-1-yl)borate; M = Na, K, or Tl) and characterized by analytical and spectral data (IR, ESIMS, 1H and 13C NMR). The structures of [Ru(η 6-p-cymene)(Ph 2Bp)Cl] (1) and [Ru(η 6-p-cymene)(Tp)Cl] (3) have been established by single-crystal X-ray diffraction analysis. Electrochemical studies allowed comparing the electron-donor characters of Tp and related ligands and estimating the corresponding values of the Lever E L ligand parameter. The complexes [Ru(η 6-p-cymene)(κ 2-L)X] and [Ru(η 6-p-cymene)(κ 3-L)]X•nH 2O act as catalyst precursors for the diastereoselective nitroaldol reaction of benzaldehyde and nitroethane to the corresponding β-nitroalkanol (up to 82% yield, at room temperature) with diastereoselectivity toward the formation of the threo isomer.

C. Pettinari, F. Marchetti, A. Cerquetella, R. Pettinari, M. Monari, T. C. O. Mac Leod, et al. (2011). Coordination Chemistry of the (η6-p-Cymene)ruthenium(II) Fragment with Bis-, Tris-, and Tetrakis(pyrazol-1-yl)borate Ligands: Synthesis, Structural, Electrochemical, and Catalytic Diastereoselective Nitroaldol Reaction Studies. ORGANOMETALLICS, 30, 1616-1626 [10.1021/om101146q].

Coordination Chemistry of the (η6-p-Cymene)ruthenium(II) Fragment with Bis-, Tris-, and Tetrakis(pyrazol-1-yl)borate Ligands: Synthesis, Structural, Electrochemical, and Catalytic Diastereoselective Nitroaldol Reaction Studies

MONARI, MAGDA;
2011

Abstract

Novel [Ru(η 6-p-cymene)(κ 2-L)X] and [Ru(η 6-p-cymene)(κ 3-L)]X•nH 2O complexes (L = bis-, tris-, or tetrakis-pyrazolylborate; X = Cl, N 3, PF 6, or CF 3SO 3) are prepared by treatment of [Ru(η 6-p-cymene)Cl 2] 2 with poly(pyrazolyl)borate derivatives [M(L)] (L in general; in detail L = Ph 2Bp = diphenylbis(pyrazol-1-yl)borate; L = Tp = hydrotris(pyrazol-1- yl)borate; L = pzTp = tetrakis(pyrazol-1-yl)borate; L = Tp 4Bo = hydrotris(indazol-1-yl)borate, L = Tp 4Bo,5Me = hydrotris(5- methylindazol-1-yl)borate; L = Tp Bn,4Ph = hydrotris(3-benzyl-4- phenylpyrazol-1-yl)borate; M = Na, K, or Tl) and characterized by analytical and spectral data (IR, ESIMS, 1H and 13C NMR). The structures of [Ru(η 6-p-cymene)(Ph 2Bp)Cl] (1) and [Ru(η 6-p-cymene)(Tp)Cl] (3) have been established by single-crystal X-ray diffraction analysis. Electrochemical studies allowed comparing the electron-donor characters of Tp and related ligands and estimating the corresponding values of the Lever E L ligand parameter. The complexes [Ru(η 6-p-cymene)(κ 2-L)X] and [Ru(η 6-p-cymene)(κ 3-L)]X•nH 2O act as catalyst precursors for the diastereoselective nitroaldol reaction of benzaldehyde and nitroethane to the corresponding β-nitroalkanol (up to 82% yield, at room temperature) with diastereoselectivity toward the formation of the threo isomer.
2011
C. Pettinari, F. Marchetti, A. Cerquetella, R. Pettinari, M. Monari, T. C. O. Mac Leod, et al. (2011). Coordination Chemistry of the (η6-p-Cymene)ruthenium(II) Fragment with Bis-, Tris-, and Tetrakis(pyrazol-1-yl)borate Ligands: Synthesis, Structural, Electrochemical, and Catalytic Diastereoselective Nitroaldol Reaction Studies. ORGANOMETALLICS, 30, 1616-1626 [10.1021/om101146q].
C. Pettinari; F. Marchetti; A. Cerquetella; R. Pettinari; M. Monari; T. C. O. Mac Leod; L. M. D. R. S. Martins; A. J. L. Pombeiro.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/112858
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