Novel Route to Cationic Palladium(II)-Cyclopentadienyl Complexes Containing Phosphine Ligands and Their Catalytic Activities.

The Pd(II) complexes [Pd(Cp)(L)][BF] were synthesized via the reaction of cationic acetylacetonate complexes with cyclopentadiene in the presence of BF∙OEt ( = 2, = 1: L = PPh (), P(-Tol), (-methoxyphenyl)phosphine (TOMPP), -2-furylphosphine, -2-thienylphosphine; = 1, = 1: L = dppf, dppp (), dppb (), 1,5-bis(diphenylphosphino)pentane; = 1, = 2 or 3: 1,6-bis(diphenylphosphino)hexane). Complexes - were characterized using X-ray diffractometry. The inspection of the crystal structures of the complexes enabled the recognition of (Cp)⋯(Ph-group) and (Cp)⋯(CH-group) interactions, which are of C-H…π nature. The presence of these interactions was confirmed theoretically via DFT calculations using QTAIM analysis. The intermolecular interactions in the X-ray structures are non-covalent in origin with an estimated energy of 0.3-1.6 kcal/mol. The cationic palladium catalyst precursors with monophosphines were found to be active catalysts for the telomerization of 1,3-butadiene with methanol ( up to 2.4∙10 mol 1,3-butadiene per mol Pd with chemoselectivity of 82%). Complex [Pd(Cp)(TOMPP)]BF was found to be an efficient catalyst for the polymerization of phenylacetylene (PA) (catalyst activities up to 8.9 × 10 g·(mol·h) were observed).