A series of mononuclear ruthenium(II) complexes with sterically demanding bis(phosphino)methanes and arsino(phosphino)methanes as ligands

The bis(eta(3)-2-methylallyl)ruthenium(II) complexes [Ru(eta(3)-2-MeC3H4)(2 )(kappa(2)-R2PCH2PPh2)] (R = iPr 2, Cy 3) were prepared from the cycloocta- 1.5-diene derivative [Ru(eta(3)-2-MeC3H4)(2)(eta(4)-C8H12)] (1) and the uns ymmetrical bis(phosphino)methanes R2PCH2PPh2 (R = iPr, Cy). Treatment of 2 with benzoic acid and with acetic acid in the presence of iPr(2)PCH(2)PPh(2 ) led, after proton-assisted cleavage of the allyl-metal bond, to the forma tion of the bis(carboxylato)ruthenium(II) compounds 4 and 5a/5b, respective ly. Similarly, the bis( trifluoroacetate) [Ru(eta(1)-O2CCF3)(2)(kappa(2)-iP r(2)PCH(2)PiPr(2))(2)] (7) was prepared and the molecular structure determi ned by X-ray crystallography. The reaction of 2 and 3 with hexafluoroaceton e afforded the chelate complexes [Ru(eta(2)-acac-f(6))(2)(kappa(2)-R2PCH2PP h2)] (R = iPr 8, Cy 9) which were also accessible from [Ru(eta(2)-OC6Cl5)(2 )(kappa(2)-R2PCH2PPh2)] (R = iPr 10, Cy 11) by treatment with Hacac-f(6). T he preparation of the non-fluorinated bis(acac) compound [Ru(eta(2)-acac)(2 )(kappa(2)-iPr(2)PCH(2)PPh(2))] (12), which could not be obtained from 2 an d Hacac, was achieved by ligand exchange from 10 and acetylacetone in the p resence of Na2CO3. The reaction of 10 with CO and CNtBu gave by partial ope ning of the chelate rings the substitution products [Ru(OC6Cl5)(2)(CO)(kapp a(2)-iPr(2)PCH(2)PPh(2))] (13) and [Ru(OC6Cl5)(2)(CNtBu)(3)(kappa(1)-Ph(2)P CH(2)PiPr(2))] (14), the latter containing the unsymmetrical bis(phosphino) methane as a monodentate ligand. With the dimer [RuCl(mu-Cl)(eta(3):eta(3)- C-10,H-16)](2) (15) as the starting material, the mononuclear ruthenium(IV) complexes [RuCl(eta(3):eta(3)-C10H16)(kappa(2)-iPr(2)PCH(2)PiPr(2))]BF4 (1 6) and [RuCl2(eta(3):eta(3)-C10H16)(kappa-P-iPr(2)PCH(2)AstBu(2))] (17) wer e prepared. (C) 2000 Elsevier Science S.A. All rights reserved.