1448993-06-3Relevant academic research and scientific papers
2-[(Diphenylphosphino)methyl]-6-methylpyridine (PN) coordination chemistry at triosmium clusters: Regiospecific ligand activation and DFT evaluation of the isomeric Os3 (CO)10 (PN) clusters
Lin, Chen-Hao,Nesterov, Vladimir N.,Richmond, Michael G.
, p. 24 - 34 (2013/10/01)
The reaction of 2-[(diphenylphosphino)methyl]-6-methylpyridine (PN) with Os3(CO) 12-n(MeCN)n [where n = 0 (1), 1 (2), 2 (3)] has been investigated. Os3(CO)12 reacts with PN in the presence of Me3NO to afford the clusters Os3(CO) 11(k1-PN) (4) and 1,2-Os3(CO)10(k1-PN)2 (5). X-ray diffraction analyses confirm the equatorial coordination of the phosphine(s) in 4 and 5, with the two phosphines in the latter cluster exhibiting a 1,2-trans orientation about the OseOs vector that contains the two ligands. Treatment of the MeCN-substituted cluster Os3(CO) 11(MeCN) and PN (1:1 ratio) in CH2Cl2 gives clusters 4 and 5, in addition to HOs3 (h1-Cl)(CO)10( (k1-PN) (6) as a result of competitive activation of the reaction solvent. Cluster 6 contains 48-and the diffraction structure reveals the presence of axial chloride and equatorial phosphine ligands which are located on adjacent osmium atoms. The bridging hydride ligand in 6 spans the Cl,P-substituted OseOs vector. The reaction of Os3(CO)10(MeCN)2 with PN furnishes 5, 6, and 1,1-Os 3 (CO)10( (k2-PN) (7) in yields that are dependent on the reagent stoichiometry and reaction solvent. The solid-state structure of 7 confirms the chelation of the PN ligand to a single osmium atom via the pyridine and phosphine moieties at axial and equatorial sites, respectively. The bonding in 7 relative to other possible stereoisomers has been explored by DFT calculations, and the diffraction structure is computed as the thermodynamically most stable form of this cluster. Cluster 4 is photosensitive and CO loss gives 7, in addition to the formation of the dihydride H 2Os3 (CO) 8 [m-CH(NC5H 3)CH2PPh2] (8), whose origin derives from the double metalation of the C-6 methyl group of the PN ligand in 7. Photolysis of 7 yields 8 without detectable observation of the expected intermediate hydride HOs3(CO)9[μ-CH2(NC5H3) CH 2PPh2]. The PN ligand in 7 undergoes PeC bond activation in toluene at 110°C to afford the 50-cluster Os3(CO) 9 (μ-C6H4 )( μ-PPh) (9), which contains face-capping benzyne and phosphinidene moieties. The bonding between the benzyne moiety and the opened Os3 frame in 9 has been examined computationally, and these data are discussed relative to s and p bonding contributions from the metalated aryl ring to the cluster polyhedron.
