engleski

Complexes of Dicyclopalladated Azobenzenes with 1, 1'-Bis(diphenylphosphino)ferrocene

Recently, considerable effort has been focused to the design and synthesis of cyclopalladated complexes containing N-donor ligands with potential application as model compounds for photoactive units in different optical devices, as differential chromogenic and fluorescent chemosensors as well as liquid crystalline materials and catalysts. In this regard, particularly interesting are complexes with azobenzenes, due to their structural, photochemical and photophysical properties. Our group has reported azobenzene palladacycles derivatized with 2, 2’-bipyridine and triphenylphosphine as side-ligands, that showed promising optical properties in solution and in the solid state. We present a series of new dicyclometallated azobenzenes (DPA) complexes with 1, 1'-bis(diphenylphosphino)ferrocene (DPPF) as auxiliary ligand, Figure 1. Complexes have been obtained by two preparative methods: liquid-assisted grinding (LAG) i.e. grinding of solid reactants in the presence of a small quantity of liquid phase and conventional solution-based reactions. The structures of complexes have been determined by the combination of powder X-ray diffraction experiments and NMR spectroscopy in solution and in the solid state. The experimental investigation was complemented by the quantum-chemical calculations in order to give rational explanation of the structures by comparing their energies with those of other conceivable isomers. Products have been additionally characterized by ESI mass spectrometry, UV-vis and fluorimetric spectroscopies.

cyclopalladated azobenzene; dppf; mechanochemistry; NMR spectroscopy

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