Molecule-Based Magnetic Compounds Made Up from Dinuclear Ruthenium(II,III) Carboxylate and Dicyanidoargentate(I)

Abstract

Mixed-metal complexes constructed from mixed-valent dinuclear ruthenium(II,III) carboxylate and dicyanidoargentate(I), K(Ru2(O2CCH3)4Ag(CN) 2 )· 4H2O (1 )a nd K 2.5(Ru2{O2CC(CH3)3}4(Ag(CN)2)3.5 )· 3H2O (2), were synthesized and characterized by elemental anal- ysis and IR and UV-visible-NIR spectroscopies. These data supported the formulation of mixed-metal adduct of Ru2(O2CCH3)4 + with two Ag(CN)2 − for 1 and mixed- metal dimer of Ru2{O2CC(CH3)3}4 + with aggregated {Ag(CN)2 − }2or3 through argentophilic Ag ··· Ag interac- tion for 2, respectively. A broadband (δ(Ru2) → δ ∗ (Ru2)) at near-IR and two bands (δ ∗ /π ∗ (Ru2) → σ ∗ (Ru − O) and π (Ru-O, Ru2) → π ∗ (Ru2)) at visible region were observed in the diffused reflectance spectra (920sh, 634, and 444 nm for 1 and 930sh, 638, and 478 nm for 2, respec- tively). Temperature dependence of magnetic susceptibility measurement (4.5-300 K) showed that the former is param- agnetic (S = 3/2) with D (zero-field splitting parameter) = 78 cm −1 and the latter weakly antiferromagnetic with g = 2.07, zJ (the exchange integral multiplied by the number of interacting neighbors) =− 0.5 cm −1 ,a ndD = 90 cm −1 .