3D molecular network and magnetic ordering, formed by multi-dentate magnetic couplers, bis(benzene)chromium(i) and [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazolidyl

Abstract

The reaction between bis(benzene)chromium(0), Cr⁰(C₆H₆)₂, and [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (abbreviated as TDTD) formed single crystals of the 1 : 1 salt, [Cr^I(C₆H₆)₂]⁺[TDTD]⁻. The crystal structure of [Cr(C₆H₆)₂][TDTD] belongs to the monoclinic P2₁/c space group, and involves a CdSO₄-type network (or quartz dual net), which is formed by CH⋯N hydrogen bonds between [Cr(C₆H₆)₂]⁺ (S = 1/2) and [TDTD]⁻ (S = 1/2). In addition to this network, the two components form an alternating chain crystal with a π–π overlap along the [110] and [10] directions. The theoretical calculations for the pairwise intermolecular magnetic exchange interactions in [Cr(C₆H₆)₂][TDTD] reveal the presence of 3D interactions, ranging from an antiferromagnetic interaction of −8.96 cm⁻¹ to a ferromagnetic one of 1.70 cm⁻¹. The temperature dependence of the paramagnetic susceptibility χ_p indicates the dominance of an antiferromagnetic interaction with a negative Weiss constant of −4.8 K and a magnetic ordering at 8 K, which can be characterized in terms of weak ferromagnetism.