Synthesis and Structural and Spectroscopic Characterization of New Ru II ‐dmso Precursors with Face‐Capping Ligands for Use in Self‐Assembly Reactions

The aim of this work is the preparation of new, easy‐to‐make, octahedral Ru II precursors with facial geometry to be used in self‐assembly reactions. We chose dmso as a leaving group and 1,4,7‐trithiacyclononane ([9]aneS 3 ), tris(pyrazolyl)methane [CH(pz) 3 , pz = pyrazol‐1‐yl], or triphos [CH 3 C(CH 2 ‐PPh 2 ) 3 ] as the face‐capping ligand (fcl). We describe here the preparation and structural characterization of three new dicationic Ru II complexes (as triflate salts) of the type fac ‐[Ru(fcl)(solv) 3 ] 2+ , namely fac ‐[Ru([9]aneS 3 )(dmso‐O)(dmso‐S) 2 ] 2+ ( 3b ), which equilibrates in solution with the linkage isomer fac ‐[Ru([9]aneS 3 )(dmso‐O) 2 (dmso‐S)] 2+ ( 3a ), fac ‐[Ru{CH(pz) 3 }(dmso‐O)(dmso‐S) 2 ] 2+ ( 7 ), and fac ‐[Ru(triphos)‐(dmso‐O) 2 (H 2 O)] 2+ ( 9 ). In all cases the preferred synthetic procedure involved coordination of the face‐capping ligand to cis ‐[RuCl 2 (dmso) 4 ] first, followed by replacement of the chlorides with dmso (or water) molecules assisted by addition of AgCF 3 SO 3 (AgOTf). NMR investigations showed that hydrolysis of the dmso ligands occurs very easily for 3 in water and for 9 in chloroform, while for complex 7 only the O‐bound dmso ligand is replaced in water. In the course of this work, the following complexes were also isolated and structurally characterized: fac ‐[Ru([9]aneS 3 )Cl(dmso‐S) 2 ][OTf] ( 2 ), trans , cis , cis ‐[RuCl 2 (dmso‐S) 2 {CH(pz) 2 (pz)}] ( 4 ), trans , cis , cis ‐[RuCl 2 (dmso‐S) 2 (pzH) 2 ] ( 5 ), fac ‐[Ru{CH(pz) 3 }Cl 2 (dmso‐S)] ( 6 ), fac ‐[Ru([9]aneS 3 )(py) 3 ][OTf] 2 ( 11 ), fac ‐[Ru([9]aneS 3 )(py) 2 ‐(CH 3 CN)][OTf] 2 ( 13 ), and fac ‐[Ru([9]aneS 3 O)(dmso‐O) 2 ‐(dmso‐S)][OTf] 2 ([9]aneS 3 O = 1,4,7‐trithiacyclononane 1‐oxide); in 4 the tripodal tris(pyrazolyl)methane acts as a bidentate ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)