Coordination properties of the 1,1′-bis[((6-methyl)-2-pyridyl)amido]ferrocene ligand towards group 11 complexes

Abstract

The coordination properties of the 1,1′-bis[((6-methyl)-2-pyridyl)amido]ferrocene ligand (L) towards group 11 and palladium complexes have been studied. L coordinates as the bridging ligand, through the pyridinic nitrogen atoms, when reacting with the gold(I) compounds [Au(OTf)(PPh₃)] and [Au(C₆F₅)(tht)] or with the gold(III) species [Au(C₆F₅)₃(tht)] leading to linear or square planar derivatives, respectively. The reaction of L with [O(AuPPh₃)₃]ClO₄ affords the tetranuclear compound [Au₄(L-H)₂(PPh₃)₄](ClO₄)₂ in which the amide groups have been deprotonated and the ligand acts as dianionic, N,N,N,N-tetradentate. The treatment of the ligand L with silver salts leads to mononuclear complexes with the ligand acting as N,N,O or N,N chelating in [AgL]OTf, or [AgL₂]OTf, or to dinuclear species with an N,N bridging ligand in [Ag₂(PPh₃)₂(μ-L)](OTf)₂. Tetracoordination around the copper atom is proposed for the copper complexes [CuL(PPh₃)₂]PF₆, [CuL]PF₆, or [CuL₂]PF₆ with the ligand coordinated in an NH,NH,N,N or an N,N chelating fashion. Finally the palladium compound [PtCl₂L] has been synthesized with a trans-chelating ligand. In the structures of some of these derivatives the presence of secondary interactions such as weak hydrogen bonds of the type C–H⋯O, C–H⋯N or C–H⋯X (X = F, Cl) or even M⋯O interactions leads to supramolecular networks.