161929-65-3Relevant academic research and scientific papers
Complexes of bis-ortho-cyclometalated bisphosphinoaryl ruthenium(II) cations with neutral meta-bisphosphinoarene ligands containing an agostic C-H...Ru interaction
Dani,Toorneman,van Klink,van Koten
, p. 5287 - 5296 (2008/10/08)
The synthesis, characterization, and reactivity of various ruthenium(II) complexes [Ru-(R-PCP)(R′-PCHP)][OTf] are presented. These complexes are highly dissymmetric and show fluxional behavior in solution. They contain one monoanionic, η3-P,C,P′-tridentate-bonded bisphosphinoaryl ligand (R-PCP = [C6H2(CH2PPh2)2-2,6-R-4]-; R = H or Br) and one neutral, trans-P,P′-bidentate-bonded bisphosphinoarene ligand (R′-PCHP = C6H3(CH2PPh2)2-3,5-R′-1). The C-H bond that is ortho to both CH2PPh2 substituents of the bidentate-bonded ligand is interacting with the metal center (i.e., has an agostic contact with the cationic ruthenium center). The location of the agostic proton in the 1H NMR spectrum as well as the three-dimensional structure of these complexes in solution was obtained by means of several two-dimensional NMR techniques (1H-1H COSY, 31P-1H COSY, 13C-1H COSY, 1H NOESY, 1H ROESY, and 31P EXSY). The 1JHC of the agostic contact amounted to 112 Hz, which represents a reduction of 46 Hz in relation with the same coupling for this C-H bond in the free ligand. Furthermore, the molecular geometry of [Ru(H-PCP)(PCHP)][OTf] in the solid state was established by single-crystal X-ray diffraction techniques, and the structural features corroborate with the observations in solution. In the complex [Ru(H-PCP)(Br-PCHP)][OTf], interconversion of the cyclometalated and neutral bisphosphine ligands via exchange of the agostic hydrogen atom from the neutral to the cyclometalated carbon to yield [Ru(Br-PCP)(H-PCHP)][OTf] was observed. A mechanistic proposal based on an aromatic electrophilic substitution is discussed. Moreover, the reaction of [Ru(OSO2-CF3)(NCN)(PPh3)] (NCN = [C6H3(CH2NMe2)2-2,6]-) with the neutral bisphosphinoarene resulted in the quantitative formation of the new cyclometalated species [Ru(R-PCP)(R-PCHP)][OTf] with the net loss of the neutral bisaminoarene ligand NCHN and PPh3.
Synthesis of a new multidentate phosphane ligand C6H2(CH2PPh2)4-1,2,4,5 - X-ray structure of a dinuclear ruthenium(II)-bridged complex: [{RuCl2(PPh3)}2{C6H 2(CH2PPh2) 4-1,2,4,5-P,P′,P″,P?}]
Steenwinkel, Pablo,Kolmschot, Sebastiaan,Gossage, Robert A.,Dani, Paulo,Veldman, Nora,Spek, Anthony L.,Van Koten, Gerard
, p. 477 - 483 (2007/10/03)
The tetrakis(phosphane oxide) C6H2{CH2P(O)Ph2}4-1,2,4,5 (5), has been prepared in high yield from the Arbuzov reaction of C6H2(CH2Br)4-1,2,4,5 (4), with excess (7 equiv.) of Ph2POEt. Subsequent reduction of 5 with HSiCl3 (12 equiv.) in C6H4Cl2-1,2 afforded the new tetraphosphane C6H2(CH2PPh2)4-1,2,4,5 (6), in high yield. The reaction of 6 with [RuCl2(PPh3)4] in CH2Cl2 afforded the green dinuclear ruthenium(II) coordination complex [{RuCl2(PPh3)}2[C6H 2-(CH2PPh2) 4-1,2,4,5-P,P′,P″,P?}]·0.5 CH2Cl2 (8), in 39percent isolated yield. The solid-state molecular geometry of 8, determined by X-ray analysis, shows that the tetraphosphane is ortho-P,P′-chelated to each of the two [RuIICl2(PPh3)] units.
Versatile N,C,N coordination behavior of a monoanionic aryldiamine ligand in ruthenium(II) complexes: Syntheses and crystal structures of [RuII{C6H3(CH2NMe2) 2-2,6}X(L)] (L = Norbornadiene, X = Cl, SO3CF3; L = PPh3, X = I)
Sutter, Jean-Pascal,James, Stuart L.,Steenwinkel, Pablo,Karlen, Thomas,Grove, David M.,Veldman, Nora,Smeets, Wilberth J. J.,Spek, Anthony L.,Van Koten, Gerard
, p. 941 - 948 (2008/10/08)
The monoanionic ligand [C6H3(CH2NMe2)2-2,6] -, a potentially terdentate N,C,N bonding system, has been employed to synthesize a series of new ruthenium(II) complexes [Ru-{C6H3(CH2NMe2) 2-2,6}X(L)] (L = PPh3, X = Cl (2a), I (2b); L = norbornadiene (nbd), X = Cl (4), η1-OSO2CF3 (5)) and [Ru{C6H3(CH2NMe2) 2-2,6}(2,2′:6′,2″-terpyridine)]Cl (3). X-ray crystal structures of 2b and 3-5 have been determined, in which the N,C,N coordination geometry with respect to the metal center is found to differ considerably. In each complex the aryldiamine ligand is terdentate, η3-N,C,N-bonded as a six electron donor system. However, depending on the other ligands in the Ru(II) coordination sphere, this ligand demonstrates considerable flexibility in adopting coordination geometries which range from meridional in 3 through pseudomeridional in 2b to pseudo facial in 4 and 5. In the structures of 4 and 5 significant distortions of the aryl ring, involving bending of the six-membered ring into a boatlike conformation, are found. The different combinations of the N,C,N ligand with sets of other ligands lead to a range of metal geometries, i.e. square pyramidal in 2b, octahedral in 3, and bicapped tetrahedral in 4 and 5.
