Willie J. Perez, Charles H. Lake, Ronald F. See, Laurence M. Toomey, Melvyn Rowen Churchill, Kenneth J. Takeuchi, Christopher P. Radano, Walter J. Boyko and Carol A. Bessel
The formation of stable, undistorted octahedral transition metal complexes which contain a trans-spanning bidentate ligand remains a synthetic challenge. The reported complexes are of the type trans-[Ru(Cl)(trpy){Ph2PC6H4CH2O(CO)Y(CO)OCH2C6H4PPh2}][PF6] [where trpy = 2,2′∶6′,2″-terpyridine and Y = (CH2)3 = C3SPAN, 6; (CH2)4 = C4SPAN, 7; or isophthalate = ISPAN, 8] and represent the first examples of trans-spanned transition metal complexes which display little bond angle distortion from octahedral geometry and also contain a bridging linkage which is stable towards oxidation, reduction and hydrolysis. These complexes were characterized by elemental analyses, cyclic voltammetry, conductivity and UV-VIS spectroscopy. COSY, HETCOR and variable temperature (1H and 13C) NMR spectra of the complexes are consistent with a flexible spanning linkage that does not demonstrate restricted rotation about either the P–Cipso or the Ru–P bonds while the X-ray crystal structure analysis of 7 showed that the spanning linkage is positioned to one side of the meridional chloride.