84802-26-6Relevant academic research and scientific papers
Reactivity and ligand dynamics of a skeletally chiral metal cluster: [(μ3-η2-C2tBu)(CO) 9Ru3]2(μ4-Hg)
Hajela, Sharad,Novak, Bruce M.,Rosenberg, Edward
, p. 468 - 475 (2008/10/08)
The reaction chemistry and ligand dynamics of [Ru3(CO)9(μ3-η2-C 2tBu)]2(μ4-Hg) (3) have been studied. It has been found that phosphine substitution can be affected thermally, photochemically and by electron transfer. In all cases the same substitution products are observed: [Ru3(CO)9(μ3-η2-C 2tBu)](μ4-Hg)-[(Ru3(CO) 8(μ3-η2-C2 tBu)(PPh3)] (4a), [Ru3(CO)8(μ3-η2-C 2tBu)(PPh3)]2(μ4-Hg) (4b), and [Ru3(CO)8(μ3-η2-C 2tBu)(PPh3)](μ4-Hg)[Ru 3(CO)7(μ3-η2-C 2tBu)(PPh3)2] (4c). Compound 3 shows high thermal stability with respect to reductive elimination of Hg metal. However, redistribution reactions occur at elevated temperatures. The redistribution equilibrium constant is found to be 0.10 at 80°C for the monophosphine derivative [Ru3(CO)9(μ3-η2-C 2tBu)](μ4-Hg)[Ru3(CO) 8(μ3-η2-C2 tBu)(P(Ph)2(CH2CH2COOC 2H5))] (4d). The thermal reaction of 3 with H2 gives H3Ru3(CO)9(μ3-η 1-CCH2C(CH3)3) (5), HRu3(CO)9(μ3-η2-C 2tBu) (1), H4Ru4(CO)12, and Hg metal as the major products. The photochemical reaction of 3 and H2 yields the same products except H4Ru4(CO)12 is not produced under these conditions. When 3 is reacted with zinc metal, transmetalation is observed to give [Ru3(CO)9(μ3-η2-C 2tBu)2](μ4-Zn) and Hg metal. Reaction of 3 with Br2 gives the cleavage product (CO)9(μ3-η2-C2 tBu)Ru3HgBr (2b) while reaction with HCl gives 1 and (μ3-η2-C2tBu)(CO) 9Ru3HgCl (2c). Variable-temperature 13C and 31P NMR of 3, 4a, and 4b reveal axial-radial exchange processes similar to those observed for related compounds. Variable-temperature 31P NMR of a mixture of the diastereomers of [Ru3(CO)9(μ3-η2-C 2tu)](μ4-Hg)[Ru3(CO) 8(μ3-η2-C2 tBu)(P-(CH3)(C6H5CH 2)(C6H5))] (4f and 4f′) shows racemization at high temperatures which is interpreted as a rearrangement of the metal skeleton from its chiral ground state to a symmetrical structure containing a face-bridging mercury.
