| Thioarsenates are a very active research area in recent years,because they are new function materials with the diversity of fascinating architectures and potential applications as photocatalys, magnetism, luminescence and nonlinear optical properties. By using organic chelating amines or metal-amine complex cations as the structuredirecting agents, 27 new polynary thioarsenates were prepared under solvothermal conditions, and characterized by powder X-ray diffraction, elemental analysis, UV/Vis, FT-IR and single crystal X-ray diffraction. The magnetic, luminescence, thermal stability, nonlinear optical properties and photocatalytic properties of some thioarsenates were further investigated. 1. Lanthanoid thioarsenates: A series of lanthanoid thioarsenates [Er(dien)2As S4](1)、[Ln(teta)(en)As S4] {Ln = Dy(2), Ho(3), Tm(4)}, [Ln(dap)3As S4] {Ln = Tb(5), Dy(6), Ho(7), Er(8)} and [Ln(dap)2]2(μ-η1:η1:η1:η1-As S4)(μ-η1:η1-As S4)]n {Ln = Ce(9), Pr(10), Nd(11), Sm(12)} based on [As S4]3- anions were obtained by using chelating organic-amines(dap = diaminopropane, dien = diethylenetriamine, teta = triethylenetetramine, en = ethylenediamine) as strcture-diecting agents under solvothermal conditions. In compounds 1~8, the [As S4]3- shows that chelating coordination mode is bound to [Ln(dap)3]3+/[Er(dien)2]3+ cation, forming neutral molecules. Compounds 12~15 contain two different [As S4]3- bridging coordination modes, namely μ-η1:η1:η1:η1-As S4 and μ-η1:η1-As S4, which are linked alternately with [Ln(dap)2]3+ groups into 1-D neutral chains [Ln(dap)2]2(μ-η1:η1:η1:η1-As S4)(μ-η1:η1-As S4)]n. Their absorption edges vary from 2.38 to 2.95 e V, which exhibit properties of the wide band-gap semiconductor. In order to understand further the electronic structures of compounds 9~12, compound 9 was selected as their representatives to calculate the band structures and density of states. Compounds 5, 6 and 10 show good luminescence properties.2. Non-centrosymmetric lanthanoid thioarsenates: A series of non-centrosymmetric lanthanoid thioarsenates [Ln(teta)(μ-η1:η2:η1-AsIIIS3)]n {Ln = Ce(13), Pr(14), Nd(15) and Sm(16) }, [Ln(teta)(en)(μ-η1:η1:η1-AsVS4)]n {Ln = La(17), Ce(18), Pr(19) and Nd(20)} in the presence of chelating organic-amines(teta and en) as strcture-diecting agents were prepared by the solvothermal reaction of K3 As O3, S and Ln Cl3. In compounds 13~20, acentric [AsIIIS3]3-/[AsVS4]3- anions acting as bridging ligands link unsaturated lanthanide complexes [Ln(teta)]3+/[Ln(teta)(en)]3+ into two types of 1-D non-centrosymmetric chains. Their absorption edges vary from 2.75 e V to 3.04 e V, which exhibit wide-band-gap semiconductor properties. Morever, the magnetic properties of compounds 13~16 and 18~20 were also studied.3.Manganese thioarsenate:A series of organic hybrid manganese thioarsenates(IV) [Mn(en)2Cu As S4]n(21), α-[Mn(dien)2][Mn(dien)As S4]2(22), β-[Mn(dien)2][Mn2(dien)2-(As S4)2](23), [Mn(teta)As S4]n(24), {[Mn(dap)2][Mn(dap)As S4]2}n(25) and [Mn(Hen)2-(As S4)2]·2(Hen)(26) in the presence of chelating organic-amines(teta, dien, dap and en) as strcture-diecting agents were prepared under solvothermal conditions. Compound 21 displays a 1-D neutral chain, which represents the only example of incorporation of unsaturated [Mn(en)2]2+ complex into the heterometallic [Cu As S42-]n framework. Compound 22 and 23 consists of discrete [Mn2(dien)2(As S4)2]2-cluster and charge compensating complex cation [Mn(dien)2]2+, where the flexible dien molecule should be responsible for the different conformation. Compound 24 shows a 1-D neutral chain constructed by the combination of complex [Mn(teta)]2+ ions and tetrahedral [As S4]3-anions. Compound 25 exhibits a rare 2-D {[Mn(dap)2][Mn(dap)As S4]2}n layer based on the linkages of [As S4]3- anions and [Mn(dap)x]2+(x = 1, 2) groups. Compound 26 contains a [Mn(Hen)2(As S4)2]2- anion built from two [As S4]3- anions bound to [Mn(Hen)2]4+ cation, and two protonated Hen+ cations, where en in [Mn(Hen)2]4+cation acts as rare monodentate ligand, mainly because en usually displays the mode of chelating coordination. Their absorption edges can be estimated as 1.99 e V~2.68 e V, which exhibit the properties of wide band-gap semiconductor. Compounds 21, 22, 24 and 25 show fluorescence properties.4. Crystalline proustite:Crystalline proustite Ag3 As S3(27) has been successfully prepared by the reactions of As2O3, Ag NO3 and S in dap under solvothermal condition. The three-dimensional polar framework of 27 is constructed by the linkages of unsymmetrical [As S3] trigonal pyramids and T-shaped [Ag S3] units via bridging S atoms. Compound 27 shows good second harmonic generation(SHG) properties. The absorption edge of compound 27 is 2.03 e V, exhibiting properties of the semiconductor, and its theoretical band structure has also been studied. Photocatalytic experiments have shown the ability of compound 27 in the degradation of methylene blue(MB) under visible light(λ > 420 nm). |
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