Intermolecular stabilization in new 2-iminopyridine derivatives complexes of Pd(II) and their reactivity towards alkenes

Abstract

Two new iminopyriridine ligands (1-2) and two new neutral Pd(II) complexes (4-5) were designed, synthesized and characterized by spectroscopic and spectrometric techniques. Molecular structures of compounds 1, 3 and 5 were obtained by X-Ray Diffraction. Addition of AgPF6 to compounds 4-5 produced two new cationic Pd(II) complexes stabilized by an exocyclic nitrile intermolecular interaction (6-7). The spectrometric characterization of these compounds confirms a dimeric nature of the complexes and an enhanced air/thermal/light resistance. The reactivity towards ethylene oligomerization/polymerization of all complexes (4-7) at 1 bar was evaluated, either as single component or with 1 equivalent of B(C6F5)(3). The change of the counterion from PF6- to OTf- allowed to obtain the compound 8, where an improvement of the reactivity was observed. ESI-MS experiments of 8 showed the insertion of up to 16 units of ethylene in the chain. (c) 2018 Elsevier B.V. All rights reserved.