Resonance Raman, X-ray Crystallographic, and Magnetic Susceptibility Studies of Metal-Metal-Bonded MoRu and WOs Porphyrin Dimers. 1. Evidence for an Unusual MO Diagram

Structural and Spectroscopic Characterization of a Diruthenium o-Dioxolene Complex Possessing a Singly Occupied Molecular Orbital Delocalized over the Entire Molecule, [Ru2(3,6-DTBDiox)4]-

Chemical oxidation of [Ru2(6+)(3,6-DTBCat)4]2- affords [n-Bu4N][Ru2(3,6-DTBDiox)4].acetone (2.acetone). The oxidized species was characterized by X-ray crystallographic analysis and EPR, and the delocalization of the unpaired electron over the entire molecule was indicated. This example showed that the utilization of redox-active ligands into a Ru2 complex expanded the degree of freedom in the electronic structure. DFT calculations support this view, and the spin population was estimated to be approximately 18% and 82% for the Ru2 core and the four dioxolene ligands, respectively.

Spectroscopic and Structural Study of Metal−Metal Bonded Metalloporphyrinic Derivatives: the Case of Rhodium−Indium

The synthesis and spectroscopic characterization of heterometallic porphyrinate derivatives containing rhodium-indium metal-metal bonds are reported. The investigated compounds are represented by the formula [(Porph)RhIn(Porph')], where Porph and Porph' are OEP, TPP, beta-Cl(4)TPP, beta-Cl(8)TPP, or TPyP. UV-Visible spectroscopy of the title complexes confirms the presence of a strong pi-pi interaction between the macrocycles in each derivative and denotes the effect of the nontransition metal in their optical features. For comparison purposes, a new bimetallic complex with a rhodium-thallium metal-metal bond is also presented. According to (1)H and (13)C NMR data, we were able to distinguish two major NMR regions: the endo- between the metal-metal bonded macrocycles and the exo-, which are characteristic features of porphyrinic complexes at very close proximity. X-ray absorption spectroscopy (XAS) structural characterization of Rh-In bond was performed on the [(OEP)RhIn(OEP)] complex, in the fluorescence mode, and we essentially focused on the metal-metal distance determination. Finally, the distance of 2.543(3) A was deduced from the X-ray structure of a new [(TPP)RhIn(TPyP)] derivative.