Structural, magnetic, and 1H NMR spectral study on lantern-type cis- and trans-diruthenium(II,III) complexes with two formamidinato and two acetato bridges

Lantern-type dinuclear complexes, cis-[Ru2(4-Me-pf)2(O2CMe)2Cl] and trans-[Ru2(2,6-Et2-pf)2(O2CMe)2Cl] (4-Me-pf− = N,N′-bis(4-methylphenyl)formamidinate ion and 2,6-Et2-pf− = N,N′-bis(2,6-diethylphenyl)formamidinate ion), were prepared and characterized. The dinuclear structures with cis- and trans-arrangements of the bridging ligands were confirmed by the X-ray crystal structures as well as 1H NMR spectra (298 K) in CD2Cl2, where the proton signals were observed at widely spread positions δ = − 80 to 25 ppm. Variable-temperature magnetic moments (2–300 K) showed the existence of three unpaired electrons in dinuclear units with large D values (65 cm− 1 for cis-Ru2II,III and 90 cm− 1 for trans-Ru2II,III).