Resonance Raman and X-ray Crystallographic Studies of Intertriad Metal-Metal Bonds. 2. WRu and MoOs Porphyrin Dimers.

Solution ((1)H NMR, Evans method magnetic susceptibility, resonance Raman) and X-ray crystallographic spectroscopic studies of intertriad heterodimeric [(OEP)MoOs(OEP)] (3), [(OEP)WRu(OEP)] (4), [(OEP)MoOs(TPP)]PF(6) (5(+)), and [(OEP)WRu(TPP)]PF(6) (6(+)) metalloporphyrins are reported (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrinato; TPP = 5,10,15,20-tetraphenylporphyrinato). Evans method magnetic susceptibility data indicate that 3 and 4 contain two unpaired electrons in the ground electronic configuration. Resonance Raman spectra of 3, 4, 5(+), and 6(+) suggest that WRu bonds are 5-10% stronger than corresponding MoOs species. Structural characterization of 5(+) and 6(+) demonstrates metal-metal bond lengths of 2.30 (WRu) and 2.24 (MoOs) Å, respectively. The possibility of a special stability associated with polar heterometallic multiple bonds is discussed.