The syntheses and X-ray structures of the complexes Ru(S-dmso)Cl2(opda) (1) and Ru(NH3)2Cl2(bqdi) (2) are described (opda= o-phenylenediamine, bqdi= o-benzoquinonediimine). Optical absorption and emission, vibrational (resonance Raman), and electrochemical data are discussed. We explore the nature of the ruthenium benzoquinone electronic interaction in species 2 primarily within the framework of density functional theory (DFT) but also using INDO/S to extract Coulombic and exchange integrals. The resonance Raman and emission data were understood in terms of a common set of coupled vibrations localized primarily within the ruthenium metallacycle ring. Experimental and computational data were also compared among a select group of ruthenium bqdi species with other spectator ligands, specifically ammonia, 2,2'-bipyridine, and 2,4-pentanedione. The changes in the electrochemistry, optical spectroscopy, and vibrational spectra with changing spectator ligand donicity were explained within a common theoretical (DFT) model which further provided a detailed analysis of the variation in the molecular orbital descriptions. With the application of an extended charge decomposition analysis (ECDA), a detailed picture emerged of the bonding between the bqdi ligand and the metal atom, illustrating the coupling between the orbitals of each fragment as a function of orbital symmetry and charge transfer between the fragments of the complex. Metal-to-bqdi pi-back-donation is seen to be very important.

A one-pot reactions of cobalt powder with iron(II) chloride in dimethylformamide (DMF; 1) or dimethyl sulfoxide (DMSO; 2) solutions of polydentate salicylaldimine Schiff base ligands (H(2)L(1), 1; H(4)L(2), 2) based on 2-aminobenzyl alcohol (1) or tris(hydroxymethyl)aminomethane (2), formed in situ, yielded two novel heterometallic complexes, [Co(III)(2)Fe(III)(2)(L(1))(6)]·4DMF (1) and [Co(III)(4)Fe(III)(4)(HL(2))(8)(DMSO)(2)]·18DMSO (2). Crystallographic investigations revealed that the molecular structure of 1 is based on a tetranuclear core, {Co(III)(2)Fe(III)(2)(μ-O)(6)}, with a chainlike metal arrangement, while the structure of 2 represents the first example of a heterometallic octanuclear core, {Co(III)(4)Fe(III)(4)(μ-O)(14)}, with a quite rare manner of metal organization, formed by two pairs of {CoFe(HL(2))(2)} and {CoFe(HL(2))(2)(DMSO)} moieties, which are joined by O bridges of the Schiff base ligands. Variable-temperature (1.8-300 K) magnetic susceptibility measurements showed a decrease of the μ(B) value at low temperature, indicative of antiferromagnetic coupling (J/hc = -32 cm(-1) in 1; J/hc = -20 cm(-1) in 2) between the Fe(III) magnetic centers in both compounds. For 2, three J constants between Fe(III) centers were assumed to be identical. High-frequency electron paramagnetic resonance spectra allowed one to find spin Hamiltonian parameters in the coupled-spin triplet and quintet states of 1 and estimate them in 2. The "outer" and "inner" Fe atoms in 2 appeared separately in the Mössbauer spectra.

The synthetic route to a new fully conjugated phenanthroline appended phthalocyanine is described. This compound has been fully characterised by elemental analysis, UV-VIS, IR, MS and 1H NMR spectroscopy.