Yazar "Passarelli, Vincenzo" seçeneğine göre listele

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    Iridium(i) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrositytation catalysts
    (Royal Soc Chemistry, 2021) Karata, Mert Olgun; Alici, Bulent; Passarelli, Vincenzo; Ozdemir, Ismail; Perez-Torrente, Jesus J.; Castarlenas, Ricardo
    A set of iridium(I) complexes of formula IrCl(kappa C,eta(2)-I(R)Cou(R))(cod) or IrCl(kappa C, eta(2)-Bz(lR)Cou(R))(cod) (cod = 1,5-cyclooctadiene; Cou = coumarin; I = imidazolin-2-carbene; Bzl = benzimidazolin-2-carbene) have beeen prepared from the corresponding azolium salt and [ir(mu-OMe)(cod)](2) in THE at room temperature. The crystalline structures of 4b and 5b show a distorted trigonal bipyramidal configuration in the solid state with a coordinated coumarin moiety. In contrast, an equilibrium between this pentacoordinated structure and the related square planar isomer is observed in solution as a consequence of the hemilability of the pyrone ring. Characterization of both species by NMR was achieved at the low and high temperature limits, respectively. In addition, the thermodynamic parameters of the equilibrium, Delta H-R and Delta S-R were obtained by VT H-1 NMR spectroscopy and fall in the range 22-33 kJ mol(-1) and 72-113 J mol(-1) k(-1), respectively. Carbonylation of IrCl(kappa C,eta(2)-BzI(Tol)Cou(7.8-Me2))(cod) resulted in the formation of a bis-CO derivative showing no hemilabile behaviour. The newly synthesised complexes efficiently catalyze the hydrosilylation of alkynes at room temperature with a preference for the beta-(Z) vinylsilane isomer.
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    Pentacoordinated Rhodium(I) Complexes Supported by Coumarin-Functionalized N-Heterocyclic Carbene Ligands
    (Amer Chemical Soc, 2018) Karatas, Mert Olgun; Di Giuseppe, Andrea; Passarelli, Vincenzo; Alici, Bulent; Perez-Torrente, Jesus J.; Oro, Luis A.; Ozdemir, Ismail
    New coumarin-tethered benzimidazolium (BzICou(R)HCl) and imidazolium (ICou(R)HCl) salts have been prepared as precursors for coumarin-NHC rhodium(I) complexes RhCl(NHC)(cod). Trigonal bypiramidal pentacoordinated bis-coumarin-NHC rhodium(I) species, RhCl(NHC)(2), can be obtained by heating rhodium-cod derivatives in the presence of coumarin-azolium salts and a base. These unusual species are stabilized by coordination of the unsaturated bond of both coumarin moieties by the same enantioface. The allyl substituent on doubly functionalized NHC competes for coordination with coumarin wingtips. DFT calculations upon coordination of the olefin moieties support the experimental results.
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    Preparation of Mixed Bis-N-Heterocyclic Carbene Rhodium(I) Complexes
    (Mdpi, 2022) Azpiroz, Ramon; Olgun Karatas, Mert; Passarelli, Vincenzo; Ozdemir, Ismail; Perez-Torrente, Jesus J.; Castarlenas, Ricardo
    A series of mixed bis-NHC rhodium(I) complexes of type RhCl(eta(2)-olefin)(NHC)(NHC') have been synthesized by a stepwise reaction of [Rh(mu-Cl)(eta(2)-olefin)(2)](2) with two different NHCs (NHC = N-heterocyclic carbene), in which the steric hindrance of both NHC ligands and the eta(2)-olefin is critical. Similarly, new mixed coumarin-functionalized bis-NHC rhodium complexes have been prepared by a reaction of mono NHC complexes of type RhCl(NHC-coumarin)(eta(2),eta(2)-cod) with the corresponding azolium salt in the presence of an external base. Both synthetic procedures proceed selectively and allow the preparation of mixed bis-NHC rhodium complexes in good yields.