Synthetic and mechanistic studies on ruthenium dicarbonyl complexes containing PhP(CH₂CH₂CH₂PCy₂)₂ (Cyttp) ligand

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• 作者：Blosser ; Patrick W. ; Wojcicki ; Andrew
• 关键词：Ruthenium complexes ; Carbonyl complexes ; Triphosphine complexes ; synaaaanti Isomerism ; Ligand substitution ; Isotope effects ; Mechanism
• 刊名：Inorganica Chimica Acta
• 出版年：2005
• 出版时间：April 15, 2005
• 年：2005
• 卷：358
• 期：7
• 页码：2341-2348
• 全文大小：240 K

文摘

A synthetic and mechanistic study is reported on ligand substitution and other reactions of six-coordinate ruthenium(II) carbonyl complexes containing tridentate PhP(CH₂CH₂CH₂PCy₂)₂ (Cyttp). Carbonylation of cis-mer-Ru(OSO₂CF₃)₂(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO₂CF₃)(CO)₂(Cyttp)]O₃SCF₃ (2(O₃SCF₃)) and, on longer reaction times, [cis-mer-Ru(solvent)(CO)₂(Cyttp)](O₃SCF₃)₂ (solvent=acetone, THF, methanol). 2(O₃SCF₃) reacts with each of NaF, LiCl, LiBr, NaI, and LiHBEt₃ to yield [cis-mer-RuX(CO)₂(Cyttp)]⁺ (X=F (3), Cl (4), Br (5), I (6), H (7)), isolated as 3aaa7(BPh₄). These conversions proceed with high stereospecificity to afford only a single isomer of the product that is assigned a structure in which the Ph group of Cyttp points toward the CO trans to X (anti when X=F, Cl, Br, or I; syn when X=H). Treatment of 2(O₃SCF₃) with NaOMe and CO generates the methoxycarbonyl complex [cis-mer-Ru(CO₂Me)(CO)₂(Cyttp)]⁺ (8), whereas addition of excess n-BuLi to 2(O₃SCF₃) in THF under CO affords mer-Ru(CO)₂(Cyttp) (9). The two ¹³C isotopomers [cis-mer-Ru(OSO₂CF₃)(CO)(¹³CO)(Cyttp)]O₃SCF₃ (2aaa(O₃SCF₃): ¹³CO trans to P_C; 2aaa(O₃SCF₃): ¹³CO cis to all P donors) were synthesized by appropriate adaptations of known transformations and used in mechanistic studies of reactions with each of LiHBEt₃, NaOMe/CO, and n-BuLi. Whereas LiHBEt₃ reacts with 2aaa(O₃SCF₃) and 2aaa(O₃SCF₃) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMeaaaCO are more complex. The methoxide combines with the CO cis to triflate in 2, and the resultant methoxycarbonyl ligand ends up positioned trans to the incoming CO in 8. A mechanism is proposed for this transformation. Finally, treatment of either 2aaa(O₃SCF₃) or 2aaa(O₃SCF₃) with an excess of n-BuLi leads to the formation of the same two ruthenium(0) isomers of mer-Ru(CO)(¹³CO)(Cyttp). These products represent, to our knowledge, the first example of a synaaaanti pair of isomers of a five-coordinate metal complex.