115981-43-6Relevant articles and documents
Chemistry of diamino-ligated methylpalladium(II) alkoxide complexes: Syntheses, X-ray crystal structures, and hydrogen-bond formation
Kapteijn, Gerardus M.,Dervisi, Athanasia,Grove, David M.,Kooijman, Huub,Lakin, Miles T.,Spek, Anthony L.,Van Koten, Gerard
, p. 10939 - 10949 (2007/10/03)
The reaction of diamino-ligated dimethylpalladium(II) complexes [Pd(Me)2(N～N)] (N～N = tmeda, bpy) with an equimolar amount of 1,1,1,3,3,3-hexafluoro-2-propanol or (substituted) phenols affords the new complexes [Pd(Me)(OR)(N～N)] (N～N = tmeda, R = CH(CF3)2 (1), C6H5 (3), C6H4-4-NO2 (4), C6H4-2-OH (11)); N～N = bpy, R = CH(CF3)2 (2)). These methylpalladium(II) alkoxides and aryloxides are isolated in high yields as yellow-orange solids and are remarkably thermally stable. Mono- or bidentate ligands can substitute the tmeda ligand in 1 to afford a variety of methylpalladium alkoxide complexes [Pd(Me)(OCH(CF3)2)L2] (L2 = bpy (2), Ph2PCH2CH2-NMe2 (12), dppe (13), 2PMe3 (14)). Crystals of 1, 3, and 4 have been subjected to X-ray diffraction studies. Crystals of 1 are monoclinic, space group P21/c, with unit-cell dimensions a = 8.2054(5) ?, b = 17.2310(9) ?, c = 11.1191-(12) ?, β = 105.701(7)°, and Z = 4. Crystals of 3 are orthorhombic, space group Pbca, with unit-cell dimensions a = 10.572(2) ?, b = 16.446(2) ?, c = 17.029(3) ?, and Z = 8. Crystals of 4 are orthorhombic, space group Pbca, with unit-cell dimensions a = 11.918(5) ?, b = 12.089(3) ?, c = 22.684(7) ?, and Z = 8. The molecular structures of these complexes show them to be square-planar species, and in 1 the Cβ-H unit of the fluorinated alkoxide is directed toward the palladium center (H?Pd = 2.89(3) ?), in what can be interpreted as the incipient stage of a β-hydrogen elimination. The palladium alkoxide or aryloxide complexes 1-4 when treated with 1 equiv of the corresponding alcohol or (substituted) phenol afford O-H?O hydrogen-bonded adducts [Pd(Me)(OR)(N～N)]·-HOR (N～N = tmeda, R = CH(CF3)2 (5), C6H5 (7), C6,H4-4-NO2 (8); N～N = bpy, R = CH(CF3)2 (6), C6H5 (9)). The X-ray molecular structures of [Pd(Me)(OC6H5)(tmeda)]·HOC6H5 (7) and [Pd(Me)(OC6H4-4-NO2)(tmeda)]·-HOC 6H4-4-NO2 (8) reveal that the aromatic alcohol is associated with the oxygen atom of the aryloxide through O-H?O hydrogen bonding. Crystals of 7 are monoclinic, space group P21/c, with unit-cell dimensions a = 15.5556-(13) ?, b = 11.0416(10) ?, c = 12.0211(11) ?, β = 91.343(8)°, and Z = 4. Crystals of 8 are monoclinic, space group P21/c, with unit-cell dimensions a = 8.7029(5) ?, b= 15.6384(11) ?, c = 16.5188(9) ?, β = 90.096(5)°, and Z = 4. Comparison of the solid state structures of [Pd(Me)(OC6H4-4-NO2)(tmeda)] (4) and its HOC6H4-NO2 adduct (8) reveal that an electron-withdrawing substituent on the aryloxide ring leads to geometric changes in the Pd-O-C unit. Proton NMR for 5-9 and the X-ray structural data of 7 and 8 indicate that the O-H?O hydrogen bonding in these adducts is strong both in solution and in the solid state. The thermodynamic parameters for the alkoxide-alcohol exchange in the adduct [Pd(Me)(OCH(CF3)2)(tmeda)]·HOCH(CF 3)2 (5) have been determined with NMR spin saturation transfer techniques and provide evidence for a five-coordinate species being the key intermediate in this intramolecular exchange reaction. Furthermore, the thermodynamic parameters for adduct formation, obtained by the Scatchard method, quantify the O-H?O hydrogen bond as being strong.
Preparation and properties of new methyl(alkoxo)- and methyl(thiolato)nickel and methyl(alkoxo)- and methyl(thiolato)palladium complexes. CO and CS2 insertion into the alkoxo-palladium bond
Kim, Yong-Joo,Osakada, Kohtaro,Sugita, Kouji,Yamamoto, Takakazu,Yamamoto, Akio
, p. 2182 - 2188 (2008/10/08)
Reactions of fluorinated alcohols (HOCH(CF3)2, HOCH2CF3, and HOCH(CF3)C6H5) or aromatic thiols (HSC6H5 and HSC6H4-p-CH3) with dialkylnickel and -palladium complexes (NiMe2(bpy), NiEt2(bpy) (bpy = 2,2′-bipyridine), NiMe2(dpe), and PdMe2(dpe) (dpe = 1,2-bis(diphenylphosphino)ethane)) give the corresponding monoalkyl complexes with an alkoxo or a thiolato ligand (NiMe(OR)(bpy), NiEt(OR)(bpy), MMe(OR)(dpe), and MMe(SAr)(dpe) (M = Ni, Pd; R = CH(CF3)2, CH2CF3, CH(CF3)C6H5)). These complexes have been characterized by elemental analysis and NMR (1H, 31P{1H}, 19F, and 13C{1H}) spectroscopy. The methyl(alkoxo)nickel(II) and -palladium(II) complexes thus obtained react with carbon monoxide at normal pressure to give carboxylic esters in high yields. Reaction of carbon monoxide with NiMe(SAr)(dpe) (Ar = C6H5, C6H4-p-CH3) also gives the corresponding carbothioic esters in good yields, while PdMe(SPh)(dpe) is unreactive with carbon monoxide under similar conditions. The 31P{1H} and 13C{1H} NMR spectra of the reaction mixture of PdMe(OCH(CF3)2)(dpe) with an equimolar amount of 13CO at -60°C show the formation of PdMe (13COOCH(CF3)2)(dpe) produced through insertion of the carbon monoxide into the Pd-O bond. When the reaction temperature is raised to -20°C, this alkoxycarbonyl complex undergoes reductive elimination to give 1,1,1,3,3,3-hexafluoro-2-propyl acetate. The reaction is accompanied by simultaneous decarbonylation of the alkoxycarbonyl ligand to regenerate PdMe(OCH(CF3)2)(dpe). The reaction of PdMe(OCH(CF3)Ph)(dpe) with carbon disulfide gives an isolable palladium complex, PdMe(SCSOCH(CF3)Ph)(dpe), formed by insertion of CS2 into the Pd-O bond, while PdMe(SPh)(dpe) is unreactive with CS2.
