Synthesis of a PennPhos-ruthenium(II) complex: The first crystal structure of a PennPhos-metal complex

The chiral bis(phosphine) ligand P,P'-1,2-phenylenebis[(1R,2S,4R,5S)-2,5-dimethyl-7-phosphabicyclo [2.2.1]heptane], [(R,S,R,S)-Me-PennPhos] (1) reacts with trans-RuCl2(NBD)Py-2 (NBD = norbornadiene, Py = pyridine) (2) in CH2Cl2 at 45degreesC to form two diastereomers of the triply chloride bridged cation [{(1)RuPy}(2)(mu-Cl)(3))][Cl-] (3) in the ratio 1:3. The isomers were studied by NMR spectroscopy and separated by crystallization from CD2Cl2-hexanes mixture. The major diastereomer is one of the anti-diastereomers and contains face-sharing bioctahedral diruthenium (Ru(II, II)) molecules with a Ru-Ru distance of 3.289 Angstrom. This diastereomer crystallizes in the monoclinic space group C2 (No. 5) with the cell dimensions a(Angstrom) = 28.102(2), b(Angstrom) = 20.5344(15), c(Angstrom) = 12.7692(10), beta(degrees) = 95.7411(16), V(Angstrom(3)) = 7331.6(9), and Z = 4. The Me-PennPhos ligand adopts an unexpected bent, non-C2 symmetric conformation upon coordination to ruthenium.