Structure and dynamic properties of substituted carbonylhydride clusters H2RuOs3(CO)13 and H4Ru4(CO)12 containing functionalized phosphines

Abstract

The derivatives of the H 2 RuOs 3 (CO) 13 and H 4 Ru 4 (CO) 12 carbonylhydride clusters con taining functionalized (including chiral) phosphines were synthesized. The solid state struc ture of H 2 RuOs 3 (CO) 12 (Ph 2 P(C 4 H 3 S)) was determined by X ray diffraction analysis. The structures of other compounds in solution were determined using IR and 1 H and 31 P NMR spectroscopy. A study of the temperature dependences of the 1 H NMR spectra of the phos phine substituted tetrahedral clusters along with the analysis of literature data for their analogs showed that compounds of this type exist in solution as an equilibrium mixture of isomers, which differ in arrangement of the hydride ligands at the cluster skeleton. Interconversion of the isomeric forms is due to migration of the hydride ligands over the cluster skeleton. A general model for this dynamic process was proposed. The model is consistent with both our data and earlier results of other authors.Carbonylhydride clusters of the iron subgroup transi tion metals are used as efficient catalysts in hydrogena tion of unsaturated organic compounds. 1-4 From this point of view, it seems most attractive to consider phos phine substituted derivatives of the H 4 Ru 4 (CO) 12 and H 2 RuOs 3 (CO) 12 clusters, whose activity in various or ganic reactions is well known. 1-14 Reactions of asymmet ric synthesis 15 are especially interesting from the theoreti cal and applied viewpoints, and reactions of this type catalyzed by cluster compounds have been most poorly studied up to date, and only restricted examples of using the clusters in asymmetrical catalysis are available in the literature. 16-18As a rule, in the organometallic complexes of this type the hydride ligands participate in the low barrier dynamic processes, such as hydride migration over the cluster skeleton in solution 19-24 and even in the solid phase. 25-27 The fast intramolecular hydride exchange in the cluster compounds in solution has been evidenced for the first time for a series of compounds H 4 Ru 4 (CO) 12-x L x (L = P(OMe 3 ), x = 1-4). 28 However, subsequent more detailed studies 22,29 of the structure of the ligand environment and mechanism of dynamic processes in these compounds revealed no general pattern, and some conclusions of the above cited works even contradict each other.In this work, we synthesized new tetrahedral mono substituted carbonylhydride clusters with functional ized phosphine ligands H 2 RuOs 3 (CO) 12 (PS) (1) and H 4 Ru 4 (CO) 11 L (2-5), where L = POx (2), PSug (3), PInd (4), and PStyr (5); PS is thienyldiphenylphosphine, POx is (1R,9R)[2(oxymethylquinolisidinyl)ethyl]di(2 phenylethyl)phosphine, PSug is (2 [5 (2,2 dimethyl 1,3 dioxolan 4 yl) 2,2 dimethyltetrahydrofuro[2,3 d][1,3]di oxol 6 yl]oxyethyl)di(2 phenylethyl)phosphine, PInd is [2 (1 indolyl)propyl]di(2 phenylethyl)phosphine, PStyr is (2 phenylpropyl)distyrylphosphine. The structures of compounds 1-5 in solution were studied, and a model for the dynamic behavior of their coordination sphere was proposed.