Synthesis, Structures, Magnetic and Luminescent Properties of a Series of Iron(II) and Zinc(II) Coordination Frameworks with Versatile 4‐Substitued 1, 2,4‐Triazole Ligands

Abstract

Three multi‐dentate 1, 2,4‐triazole derivative ligands containing different 4‐substituted groups, namely N‐1, 2,4‐triazol‐4‐yl(pyridin‐3‐yl)methylenimine (L1), N‐1, 2,4‐triazol‐ 4‐yl(pyridin‐4‐yl)methylenimine (L2), and 4‐(2‐pyridine)‐1, 2,4‐triazole (L3) were used to isolate five iron(II) and zinc(II) coordination frameworks, [Zn(μ2‐L1)Cl2] (1), [Zn(μ2‐L2)Br2] (2), [Fe(L1)2(NCS)2(H2O)2] (3), [Fe(L3)2(dca)2(H2O)2] (4), and [Fe(L3)2(μ2‐dca)] (5) (dca = dicyanamide anion). When different zinc(II) salts were used to react with L1 and L2 under solvothermal conditions, two one‐dimensional (1D) zinc(II) coordination frameworks 1 and 2 containing four‐coordinate central zinc(II) atoms were isolated. 1 is a 3D achiral supra‐molecular framework, whereas 2 is a 3D chiral supra‐molecular framework containing helical chains on a 21 axis. 3 is a mono‐nuclear iron(II) coordination framework containing six‐coordinate central FeII atoms. When L3 was employed, mono‐nuclear iron(II) framework 4 and 1D iron(II) chain 5 could be isolated when different amounts of Nadca were introduced into the reaction system. Variable‐temperature magnetic susceptibility data of 3–5 were recorded in the 2–300 K temperature range indicating weak anti‐ferromagnetic interactions. The solid‐state luminescent properties of coordination polymers 1 and 2 were also investigated at room temperature.

Catalytic Preparation of 1-Aryl-Substituted 1,2,4-Triazolium Salts

“…Purification by column chromatography (silica, 5% methanol in dichloromethane) yielded the product as a pale yellow powder in 30% yield (2.22 g, 15.2 mmol). The measured analytical data are in agreement with their literature values. , …”

“…To explore the scope of the copper-catalyzed N-arylation, we prepared a variety of 4-R-4 H -1,2,4-triazoles 1a – 1m from the corresponding primary amines R-NH 2 as described in Scheme b. − Table summarizes the results of the 1-arylation of 1a – 1m with diphenyliodonium tetrafluoroborate using our previously optimized conditions. Based on NMR studies, 100% conversion was observed with all 4-R-4 H -1,2,4-triazoles 1a – 1m , and the corresponding 1-phenyl-4-R-4 H -1,2,4-triazolium salts 2a – 2m were obtained as sole products in good to excellent yields (Figures S002–S015).…”

“…The measured analytical data are in agreement with their literature values. 53,54 2-(4H-1,2,4-Triazol-4-yl)pyrimidine (1m). The title compound was prepared on a 100 mmol scale according to general procedure 1b.…”