Europium Pyridinethiolates: Synthesis, Structure, and Thermolysis

Abstract

The transmetalation reaction of Hg(SPy)2 (SPy = S-2-NC5H4) with Eu in pyridine gives the europium(II) pyridinethiolate coordination complex (py)4Eu(SPy)2 (1) in 96% isolated yield. The reaction of 1 with BIPY in THE results in displacement of the pyridine ligands and the formation of the divalent coordination complex (BIPY)-(THF)2Eu(SPy)2 (2). Low-temperature single-crystal X-ray diffraction experiments show that 1 and 2 are molecular 8 coordinate compounds. They are both intensely colored due to the presence of a visible europium-to-pyridine or europium-to-BIPY charge transfer (CT) absorption band. Trivalent [PEL][Eu(SPy)4] (3) was prepared from the reaction of Eu/Hg amalgam with PySSPy in the presence of [PEt4][SPy], X-ray diffraction analysis of 3 shows that all the pyridinechalcogenolate ligands are chelating the Eu(III) ion and there are three different eight coordinate isomers within the unit cell. Compound 3 is intensely colored because of a visible S-to-Eu CT absorption. At 500 °C, 3 decomposes to give EuS and a mixture of PySSPy, PySPy, EtSPy, and SPEta. Crystal data (Mo Ka, 153(5) K): 1, orthorhombic space group PnalU, a = 19.006(2) k,b = 9.724(5) k,c= 15.592(5) Á, Z = 4; 2, monoclinic space group Cc, a = 9.851( 2) Á, b = 16.817(3) Á, c = 17.271(2) Á, ß = 92.67(2)°, Z = 4; 3, monoclinic space group P2\/n, a = 15.043(3) k,b= 16.036(6) Á, c = 26.444(5) Á, ß = 90.54(2)°, Z= 4.

Europium chalcogenide magnetic semiconductor nanostructures

“…However, the earliest examples of precursor thermolysis to produce EuS were for Eu(II) aryl thiolate complexes [38]. Many novel low valent europium thiolate complexes have been reported [39][40][41], which sensibly match the oxidation state of europium in the molecule with that found in the target material. Unfortunately, such complexes are air-sensitive and demand strong synthetic skills for preparation.…”

Orange Electroluminescence from a Divalent Europium Complex

“…For the synthesis of EO dyes 7 and 8 the reaction conditions had to be changed because of the high basicity of the methylene bases of 23 and 24. In a one-pot sequence in acetic acid anhydride, 3-ethyl-2-methylbenzoxazolium iodide (23) and 1-hexyl-4-methylpyridinium bromide (24) were first converted to the anils by N,N-diphenylformamidine (DPFA). They were then in-situ N-acetylated at 150 C, [9] before being finally reacted with 20a and b to give dye 7 in a 50 % yield, and dyes 8a and b in an overall yield of 15 %.…”

“…There is a precedent for this assignment in divalent europium systems with other unsaturated nitrogen donor ligands. [24] The weak transition at l max = 430 nm is assigned as a 4f 6 5d 1 ®4f 7 transition by comparison of its energy and intensity with analogous transitions in other divalent europium complexes, all of which occur between l max = 415 nm and 490 nm. [17] The measured PL quantum efficiencies of 1a and 1b were identical within experimental error at F = 0.85 ± 0.05.…”

Electrooptical Chromophores for Nonlinear Optical and Photorefractive Applications

“…For the synthesis of EO dyes 7 and 8 the reaction conditions had to be changed because of the high basicity of the methylene bases of 23 and 24. In a one-pot sequence in acetic acid anhydride, 3ethyl-2-methylbenzoxazolium iodide (23) and 1-hexyl-4methylpyridinium bromide (24) were first converted to the anils by N,N-diphenylformamidine (DPFA). They were then in-situ N-acetylated at 150 C, [9] before being finally reacted with 20a and b to give dye 7 in a 50 % yield, and dyes 8a and b in an overall yield of 15 %.…”