Synthetic routes to methylpalladium(II) and dimethylpalladium(II) chemistry and the synthesis of new nitrogen donor ligand systems

• Published in: Organometallics 1990-01, Vol.9 (1), p.210-220
• Main Authors: Byers, Peter K, Canty, Allan J
• Format: Article
• Language: English
• Subjects: CATALYSIS; Chemistry; COMPLEXES; DATA; DATA ANALYSIS; ELEMENTS; Exact sciences and technology; EXPERIMENTAL DATA; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LIGANDS; MEASURING INSTRUMENTS; MEASURING METHODS; NITROGEN; NONMETALS; NUMERICAL DATA; Organic chemistry; ORGANIC COMPOUNDS; ORGANOMETALLIC COMPOUNDS; Organometalloidal and organometallic compounds; PALLADIUM COMPLEXES; Preparations and properties; SYNTHESIS; TRANSITION ELEMENT COMPLEXES 400200 > Inorganic, Organic, & Physical Chemistry; Transition metals derivatives
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om00115a033

Convenient and widely applicable synthetic routes to methylhalogenopalladium(II), PdXMe(L{sub 2}), and dimethylpalladium(II) complexes, PdMe{sub 2}(L{sub 2}), have been developed, including complexes of triphenylphosphine and a wide range of bidentate nitrogen donor ligands. These routes involve either the generation of Pd{sup II}Me{sub n} species at low temperature from methyllithium reagents and trans-PdCl{sub 2}(SMe{sub 2}){sub 2} followed by addition of ligand, PdIMe(2,2{prime}-bipyridyl) being synthesized through the oxidative-addition reactivity of Pd{sub 2}(dba){sub 3}(CHCl{sub 3}) or the facile synthesis of complexes with the reagents (PdIMe(SMe{sub 2})){sub 2} and (PdMe{sub 2}(pyridazine)){sub n} in organic solvents at ambient temperature. These reagents are particularly suitable for ligands sensitive to MeLi reagents, and (PdIMe(SMe{sub 2})){sub 2} is also a suitable substrate for the synthesis of chloro and bromo complexes, PdXMe(L{sub 2}), including PPh{sub 3} complexes. Several new nitrogen donor bidentate ligands are described, containing 1-methylimidazol-2-yl (mim) and pyridin-2-yl (py) groups in (mim){sub 2}C=CH{sub 2} and (py)(mim)C=CH{sub 2} as relatives of planar ligands such as 2,2{prime}-bipyridyl and mim, py, and pyrazol-1-yl (pz) groups in (py)(mim)CH{sub 2}, (py)(mim)CHMe, (mim){sub 2}CH{sub 2}, (mim){sub 2}CHMe, and (pz)(mim)CH{sub 2} as relatives of ligands such as (py){sub 2}CH{sub 2} and (pz){sub 2}CH{sub 2}. Methylpalladium(II) complexes of unsymmetrical bidentate ligands exhibit isomerism; e.g., isomers of PdIMe{l brace}(py)(mim)C=O{r brace} occur in the ratio 9:1, where the dominant isomer has the pyridine ring trans to methyl.