A Theoretical Probe for Structures, Metal–Metal Bonding, and Electronic Spectra of Paramagnetic Tetrapyrrolic RuII Complex

摘要: Dimeric complexes (RuIIPz)2 have been investigated using density functional theory (DFT), where Pz is a porphyrazine ligand that features 16-atom, 18-π-electron cyclic polyene aromatic skeleton. Structural optimizations in various configurations and spin states indicate (RuPz)2 favours Pz–Pz staggered conformer over an eclipsed one; the paramagnetic triplet state with configuration found as global ground state. This agrees experimental magnetic results of (RuOEPor)2 (OEPor = octaethylporphyrin) (RuPc)2 (Pc = phthalocyanine). The Ru–Ru bond length was optimized to be 2.38 A, close 2.40–2.41 A. Ru2 doubly bonded nature has evidenced by stretching vibrational frequency 202 cm–1, energy 30.7 kcal mol–1, electronic arrangement σ2π4(nonbonding-δ)4(π*)2. Further confirmation obtained from high-level wave function calculations (complete active space self-consistent field n-electron valence second-order perturbation theory). Associated solvation explicit pyridine accounting for first coordination sphere implicit continuum model long-range interaction, spectra tetrapyrrolic ruthenium complex were calculated at time-dependent DFT level.