| Abstract
| - The synthesis of a family of new Ru complexes containing meridional or facial tridentate ligands with the generalformula [RuII(T)(D)(X)]n+ [T = 2,2‘:6‘,2‘ ‘-terpyridine or tripyrazolylmethane; D = 4,4‘-dibenzyl-4,4‘,5,5‘-tetrahydro-2,2‘-bioxazole (S,S-box-C) or 2-[((1‘S)-1‘-(hydroxymethyl)-2‘-phenyl)ethylcarboxamide]-(4S)-4-benzyl-4,5-dihydrooxazole(S,S-box-O); X = Cl, H2O, MeCN or pyridine] has been described. All complexes have been spectroscopicallycharacterized in solution through 1H NMR and UV−vis techniques. Furthermore, all of the chloro complexes presentedhere have also been characterized in the solid state through monocrystal X-ray diffraction analysis. The oxazolinicS,S-box-C ligands undergo a Ru-assisted hydrolysis reaction generating the corresponding amidate anionic oxazolinicligands S,S-box-O, which are also strongly attached to the metal center and produce a strong σ-donation effect overthe Ru metal center. The redox properties of all complexes have also been studied by means of cyclic voltammetry,strongly reflecting the nature of the ligands; both effects, geometrical (facial vs meridional) and electronic (neutralvs anionic), can be unveiled and rationalized. Finally, the reactivity of the Ru−OH2 complexes has been tested withregard to the epoxidation of trans-stilbene, and it has been shown that, in this particular case, the reactivity ispractically not dependent on the redox potentials of the catalyst but, in sharp contrast, it is strongly dependent onthe geometry of the tridentate ligands.
- A family of new Ru complexes containing tridentate facial and meridional ligands together with didentate neutral and anionic oxazoline ligands have been prepared and thoroughly characterized from structural, spectroscopic, and redox viewpoints. Furthermore, it has been shown that their reactivity toward the epoxidation of trans-stilbene is strongly dependent on the geometry of the tridentate ligand.
|
