Heterometallic complexes with the mono and disubstituted [(4-pyridylamino)carbonyl]ferrocene ligands

The coordination chemistry of the ferrocene ligands [(4-pyridylamino)carbonyl]ferrocene (L1) and 1,1′-bis[(4-pyridylamino)carbonyl]ferrocene (L2) with group 11 metals and thallium has been studied, and several complexes with coordination of the metal to the pyridine nitrogen atom or to the pyridine and carbonyl group have been prepared. For the ligand L1 complexes such as [AuX(L1)] (X = Cl, C6F5), [M(PPh3)(L1)]OTf (M = Au, Ag) (OTf = trifluoromethylsulfonate), [Ag(OTf)(L1)] or [M(L1)2]+ (M = Au, Ag, Cu) have been obtained. The thallium compound [Tl2(L1)4]2+ has also been prepared by reaction of Tl(PF6) with L1 and show an interesting structural framework with formation of a metalacycle resembling a macrocyclic compound. For the disubstituted ligand L2 dinuclear complexes such as [Au2(C6F5)2(μ-L2)] or [M2(PPh3)2(μ-L2)](OTf)2 (M = Au, Ag) or the polymeric species [Ag(μ-L2)]OTf have been isolated. The crystal structures of some of these derivatives show supramolecular assemblies through hydrogen bonding.

Graphical abstractThe coordination properties of [(4-pyridylamino)carbonyl]ferrocene and 1,1′-bis[(4-pyridylamino)carbonyl]ferrocene towards group 11 metals and thallium have been studied. The structures show supramolecular arrays through hydrogen bonding, the tallium derivative presents a macrocyclic like framework with the thallium in a pyramidal geometry with a stereochemically active lone pair occupying the vacant site.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Group 11 complexes are prepared with 4-pyridylamino-carbonyl ferrocene ligands. ► A dinuclear thallium(I) complex with chelating and bridging ligands is prepared. ► The thallium atoms are occupying the apical position of a trigonal pyramid. ► The crystal structures show supramolecular arrays through hydrogen bonding. ► The free ligand undergoes a reversible one-electron oxidation process.