Synthesis, structure and computational study of 5-[(prop-2-en-1-yl)sulfanyl]-1,3,4-thiadiazol-2-amine (Pesta) and its heterometallic π,σ-complex [Cu2FeCl2(Pesta)4][FeCl4].

Copper(I) π-coordination compounds with allyl derivatives of azoles are an interesting subject of current research, but CuI π-complexes with other transition-metal ions incorporated in the structure have been virtually uninvestigated. The present work is directed toward the synthesis and structural characterization of the novel heterometallic CuI/FeII π-complex di-μ2-chlorido-1:2κ2Cl;2:3κ2Cl-tetrakis[μ2-5-(prop-2-en-1-ylsulfanyl)-1,3,4-thiadiazol-2-amine]-1:2κ2N4:N3;1(η2),κN4:2κN3;2:3κ2N3:N4;2κN3:3(η2),κN4-dicopper(I)iron(II) tetrachloridoferrate(II), [Cu2FeCl2(C5H7N3S2)4][FeCl4] (1). The structure of the 5-[(prop-2-en-1-yl)sulfanyl]-1,3,4-thiadiazol-2-amine (Pesta, C5H7N3S2) ligand is also presented. The cationic substructure in 1 consists of one FeII and two CuI ions bridged by two chloride ions along with two σ,σ- and two π,σ-coordinated ligands, whereas the anionic part is built of isolated tetrahedral [FeCl4]2- ions. π-Coordination of the Pesta allyl group to the CuI ions prevents agglomeration of the inorganic Cu-Cl-Fe-Cl-Cu part into infinate chains. An energy framework computational analysis was performed for Pesta.