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]

Abstract

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-1:2κ2 Cl;2:3κ2 Cl-tetrakis[μ2-5-(prop-2-en-1-ylsulfanyl)-1,3,4-thiadiazol-2-amine]-1:2κ2 N 4:N 3;1(η2),κN 4:2κN 3;2:3κ2 N 3:N 4;2κN 3:3(η2),κN 4-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.

3-Phenyl-4-(prop-2-en-1-yl)-5-[(prop-2-en-1-yl)sulfanyl]-4H-1,2,4-triazole

“…Due to the π,σ-coordination to copper(I) ions via the η 2 -allyl group and the two heterocyclic N atoms, Atr molecules form compounds based on dimeric building blocks {Cu 2 (Atr) 2 } that are stable both in crystalline form and in solution [18,19]. Such stability in solution (usually in ethanol or acetonitrile) is not characteristic of Cu(I) π-complexes with other allylazoles, such as 1,2,3triazoles, tetrazoles, 1,3,4-thiadiazoles, and 1,3,4-oxadiazoles [20][21][22][23]. Despite the fact that all investigated crystalline copper coordination compounds with Atr were studied by the single-crystal X-ray diffraction method, while Atr itself was characterized only by spectroscopic techniques [19], in the present work, we focused on the structural characterization of 3-phenyl-4-(prop-2-en-1-yl)-5-[(prop-2-en-1-yl)sulfanyl]-4H-1,2,4-triazole (Atr) (Figure 1) by the diffraction technique, accompanied by an energy framework computational study.…”