Early–Late Heterobimetallic Alkoxides as Model Systems for Late-Transition-Metal Catalysts Supported on Titania

Facultad de Ciencias del Medio Ambiente, University of Castilla-La Mancha, Ciudad Real, Castille-La Mancha, Spain
Chemistry (Impact Factor: 5.73). 02/2003; 9(3):671-7. DOI: 10.1002/chem.200390075
Source: PubMed


Titanium complexes with chelating alkoxide ligands [TiCp*(O(2)Bz)(OBzOH)] (1) and [TiCp*(Me)((OCH(2))(2)Py)] (2) were synthesised by reaction of [TiCp*Me(3)] (Cp*=eta(5)-C(5)Me(5)) with 2-hydroxybenzyl alcohol ((HO)(2)Bz) and 2,6-pyridinedimethanol ((HOCH(2))(2)Py), respectively. Complex 1 reacts with [(M(mu-OH)(cod))(2)] (M=Rh, Ir) to yield the early-late heterobimetallic complexes [TiCp*(O(2)Bz)(2)M(cod)] [M=Rh (3), Ir (4)]. Carbon monoxide readily replaces the COD ligand in 3 to give the rhodium dicarbonyl derivative [TiCp*(O(2)Bz)(2)Rh(CO)(2)] (5). Compound 2 reacts with [(M(mu-OH)(cod))(2)] (M=Rh, Ir) with protonolysis of a Tibond;Me bond to give [TiCp*((OCH(2))(2)Py)(mu-O)M(cod)] [M=Rh (6), Ir (7)]. The molecular structures of complexes 3, 5 and 7 were established by single-crystal X-ray diffraction studies.

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    ABSTRACT: The early–late heterometallic complexes [TiCp∗((OCH2)2Py)(μ-O)M(COD)] (M = Rh, Ir) behave as four-electron donor ligands yielding the polynuclear cationic complexes [TiCp∗(OCH2)2 Py(μ-O){M(COD)}2]OTf (M = Rh (1), Ir (2)). The molecular structure of complex 1 has been established through an X-ray diffraction study.
    No preview · Article · Aug 2004 · Journal of Organometallic Chemistry
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    ABSTRACT: The new tantalum dialkoxide complexes Cp*TaCl2(OCH2)2py (1), trans-Cp*TaMe2(OCH2)2py (2), and cis-Cp*TaMe2(OCH2)2py (3) (Cp* = η5-C5Me5; (OCH2)2py = 2,6-pyridinedimethoxide) have been synthesized. The molecular structures of complexes 1 and 2 have been studied by X-ray diffraction methods. The reaction of complex 3 with carbon monoxide renders Cp*Ta(η2-Me2CO)(OCH2)2py (4), while with isocyanides yields the respective azatantalacyclopropanes Cp*Ta(η2-Me2CNxylyl)(OCH2)2py (6) (xylyl = 2,6-dimethylphenyl) and Cp*Ta(η2-Me2CNtBu)(OCH2)2py (7). The molecular structure of complex 4 has been established by X-ray diffraction. The coordinated ketone in 4 can be reduced to 2-propanol in the presence of water. On the other hand, compound 3 reacts with triflic acid (HOTf) to render the corresponding cationic derivative [Cp*TaMe(OCH2)2py]OTf (8).
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