Quantum-chemical methods are applied to study the nature of the excited states relevant in the photophysical processes (absorption and emission) of a series of polyazaaromatic-ligand-based ruthenium-(II) complexes. The electronic and optical properties of the free polyazaaromatic ligands and their corresponding ruthenium(II) complexes are determined on the basis of correlated Hartree-Fock semiempirical approaches. While the emission of complexes containing small-size ligands, such as 1,10phenanthroline or 2,2′-bipyridine, arises from a manifold of metal-to-ligand charge-transfer triplet states ( 3 MLCTs), an additional ligand-centered triplet state ( 3 L) is identified in the triplet manifold of complexes containing a π-extended ligand such as dipyrido[3,2-a:2′,3′-c]phenazine, tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h: 2′′′,3′′′-j]phenazine, and 1,10-phenanthrolino [5,6-b]-1,4,5,8,9,12-hexaazatriphenylene. Recent experimental data are interpreted in light of these theoretical results; namely, the origin for the abnormal solvent-and temperature-dependent emission measured in π-extended Ru complexes is revisited.

Based on the type of vegetable, the different processes applied led to microstructures with different rheological properties. This study shows that particle size distribution, morphology and phase volume are important parameters to explain the complex relationship between rheology and microstructure for these types of systems.