The new monodentate phosphoramidites 8a−g and bidentate phospholanes 13a−e are prepared in an ex-chiral-pool synthesis from D-mannitol. Chiral diols 7a−g, obtained via nucleophilic ring opening of bis(epoxides) 6a−b, are the key intermediates for the production of both classes of ligands. Treatment of 8a−g or 13a−e with [PdCl 2 (COD)] or [Rh(COD) 2 ][-SO 3 CF 3 ] yield the corresponding Pd (10a, 10f, 15a) and Rh compounds (9a−g and 14a−e), respectively. The C 2 symmetry of the complexes in the solid state is demonstrated by X-ray structure investigations performed on 10a, 10f and 15a. Sur-

Two synthetic approaches towards the mononuclear complex [(tbbpy) 2 Os II (tpphz)] 2+ (tbbpy = 4,4′-di-tert-butyl-2,2′bipyridine; tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′j]phenazine) based on the precursor [(tbbpy) 2 Os II Cl 2 ] and its oxidized side product [(tbbpy) 2 Os III Cl 2 ] + are presented. The first route is analogous to that for the isostructural ruthenium complex, whereas the second strategy efficiently uses the oxidized Os III complex under reducing conditions to obtain so-called virtual dilution, which avoids the formation of the dinuclear complex [(tbbpy) 2 Os II (tpphz)Os II (tbbpy) 2 ]. Concentration-dependent [a]