851369-77-2Relevant academic research and scientific papers
Synthetic and mechanistic studies on ruthenium dicarbonyl complexes containing PhP(CH2CH2CH2PCy2) 2 (Cyttp) ligand
Blosser, Patrick W.,Wojcicki, Andrew
, p. 2341 - 2348 (2008/10/09)
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(OSO2CF 3)2(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO 2CF3)(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 3-7(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(O 3SCF3) 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 (2′(O3SCF3): 13CO trans to PC; 2″(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 2′(O3SCF3) and 2″(O3SCF 3) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMe-CO 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 2′(O3SCF3) or 2″(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 syn-anti pair of isomers of a five-coordinate metal complex.
