Nucleophilic Substitution of η5-Pyrrolyl Ligands in Ruthenium(II) Complexes

Synthesis of Coordinatively Unsaturated Tetravalent Actinide Complexes with η(5) Coordination of Pyrrole

The synthesis of new actinide complexes utilizing bridged α-alkyl-pyrrolyl ligands is presented. Lithiation of the ligands followed by treatment with 1 equiv of actinide tetrachloride (uranium or thorium) produces the desired complex in good yield. X-ray diffraction studies reveal unique η(5):η(5) coordination of the pyrrolyl moieties; when the nonsterically demanding methylated ligand is used, rapid addition of the lithiated ligand solution to the metal precursor forms a bis-ligated complex that reveals η(5):η(1) coordination as determined by crystallographic analysis.

Synthesis of heteroleptic pyrrolide/bipyridyl complexes of ruthenium(II)

The synthesis and characterization of the first heteroleptic pyrrolide/2,2′-bipyridyl complexes of ruthenium(II) are reported. Pyrroles substituted at the 2-position with X = O functionality react with Ru(bipy)2Cl2·2H2O to form complexes in which the pyrrolide ligands chelate to Ru(II). The library of pyrroles includes 2-formyl, 2-keto, 2-carboxylato, 2-sulfinyl, and 2-sulfonyl derivatives.

New pseudohalide ligands in Ru-catalyzed olefin metathesis — A robust, air-activated iminopyrrolato catalyst

Reaction of the Grubbs catalyst RuCl2(PCy3)2(CHPh) (1) with lithium 2-[(2,6-diisopropylphenyl)imino]pyrrolide·Et2O (LiNN′·Et2O) gives alkylidene complex 5, containing a chelating, σ-bound iminopyrrolato unit. The structure of 5 is confirmed by X-ray crystallography. Treatment of 5 with pyridine generates RuCl(NN′)(py)2(CHPh) (6) via displacement of PCy3. Complex 5 effects ring-closing metathesis in air, displaying high reactivity relative to 6.Key words: ruthenium, alkylidene, metathesis, pyrrolimine, iminopyrrolato.