Study On Solvothermal Syntheses,Crystal Structures And Properties Of Inorganic-Organic Chalcogenidostannates And Chalcogenidoarsenates

In the field of contemporary materials research,the study on metal chalcogenides has been widely concerned,especially the group 14 and 15 metal chalcogenide compounds are currently one of the most promising materials.As a kind of functional materials with great potential,they have broad application prospects in the fields of photocatalysis,magnetic properties,photoluminescence and semiconductor materials.Hydrothermal or solvothermal processes have the advantages of simple reaction equipment,low reaction temperature,energy saving and perfect crystal growth,and have become the mainstream method for preparing metal chalcogenides.Since the structure and properties of metal chalcogenides are largely dependent on their synthesis conditions,the solvent species,ligand species,or the introduction of different organic amines can be used as templating agents to direct the formation of a multidimensional structural framework of the compound.Through the guiding function of the templating agent,it affects the aggregation and self-assembly of basic structural units such as MQ3(M=Sb,As)and MQ4(M=Ge,Sn,As,Sb),and generates[MxQy]n-polymerized ions of different composition and structure.In this paper,different kinds of structure directing agents were introduced into the solvothermal reaction M/Q(M=Sn,As;Q?S,Se)system.A series of the following inorganic-organic chalcogenidostannates and chalcogenidoarsenates were synthesized and characterized by changing the solvent,reaction conditions and synthesis methods.And the corresponding performance tests were performed on these compounds.1.In the reaction system Ln2O3/Sn/Q(Q=S,Se),metal Ag was introduced under solvothermal conditions,and the lanthanide metal complex ion[Ln(en)4]3+ was used as a structure-directing agent to synthesize novel ternary silver-containing chalcogenidostannates[Hen]4[Er(en)4]2[Ag6Sn6S20]·3en(1),[Hen]4[Tm(en)4]2[Ag6Sn6S20]·3en(2)and[Hen]4[Yb(en)4]2[Ag6Sn6S20]·3en(3)for the first time in a single en solvent.The three compounds are characterized by the same ternary[Ag6Sn6S20]10-anion cluster with a centrally symmetric structure.In the[Ag6Sn6S20]10-anion cluster,six SnS4 tetrahedrons and six AgS3 planar triangles are joined together by co-edges,and the core structure of the six-core Ag6S6 is surrounded by two Sn3S10 units.Experiments show that the addition of metal Ag(I)in this system not only forms a novel Ag-Sn-S ternary anion structure,but also changes the way in which the basic structural units of the SnS4 tetrahedron are polymerized.Based on the synthesis of compounds 1-3,S is replaced by Se to obtain compounds[Er2(en)6(?2-OH)2]Sn2Se6(4)and[Yb2(en)6(?2-OH)2]Sn2Se6(5).Metal Ag has different effects on the synthesis of Ln2O3/Sn/S and Ln2O3/Sn/Se systems.The photocatalytic degradation activity of organic dye crystal violet(CV)under visible light irradiation was studied by using compounds 1,2 and 4 as photocatalysts in air atmosphere at room temperature.After visible light for 2.5 h,the photocatalytic degradation rates of CV by compounds 1,2 and 4 were 86.7%,82.3%and 35.1%,respectively.Compounds 1 and 2 have better results about photocatalytic degradation activity of CV than compound 4.2.(a)In the study of the synthesis method of TMC12/Sn/S/tren(or tepa)reaction system,the solvothermal synthesis method using only one chelating amine solvent as the reaction medium was changed.In this paper,the mixed amine tren and tatda were used as the reaction medium,and the compound[Mn(tren)(H2O)][Mn(baen)]3Mn4Sn6S20·9H2O(6)with T3 type supertetrahedral structure was synthesized for the first time.The T3 supertetrahedral cluster[Mn4Sn6S20]8-is constructed by the SnS4 and MnS4 tetrahedrons by co-angle connection,wherein the SnS4 tetrahedron occupies the four vertexes of the T3 cluster.Under the same condition,Se was used instead of S as a reaction raw material to obtain a binary tin selenium compound[Mn(baen)]2Sn2Se6(7).The photocatalytic degradation efficiency of organic dye CV and rhodamine B(RhB)for compound 6 was studied under visible light irradiation.After visible light irradiation for 2.5 h,the photocatalytic degradation rate of CV reached 92%,while the photocatalytic degradation rate of RhB was still less than 40%after 5 h of visible light irradiation.Therefore,compound 6 exhibited catalytic selectivity to CV.(b)The solvothermal synthesis method using chelating amine as the reaction medium was changed.Methanol was added to the chelating amine solvent,and the binuclear metal complexes[{Mn(tren)?2(?-Sn2S6)](8)?[?Zn(tren)?2(?-Sn2S6)](9)and[(Mn(tepa)}2(?-Sn2S6)](10)containing the bidentate ?-Sn2S6 ligand were successfully prepared by alcohol-solvent thermal synthesis.The anion ?-Sn2S6 in their structure acts as a bidentate ligand to link two transition metal complex ions via two trans-terminal S atoms.Synthesis experiments show that the addition of methanol plays an important role in the formation of crystals.(c)Using C2H5OH and C2H5OH/PEG-200(PEG?polyethylene glycol)solvent as solvothermal reaction medium,the reaction system TMC12/Sn/Se/en(TM=Mn,Fe,Zn,Ni)was synthesized by alcohol-solvent thermal reaction.The polyselenidostannates[TM(en)3]Sn3Se6(Se2)(TM=Mn(11),Fe(12),Zn(13))and[Ni(en)3][Sn3Se6.5(Se2)0.5](14)with the novel 1-D zigzag[Sn6Se13(Se2)]n2n-chain were synthesized by using C2H5OH as solvent.The structural feature of 11-13 is that they all contain a novel 2-D[Sn3Se6(Se2)]n2n-anion layer which exhibits a special core shape and produces a series of nanoscale channels through the ordered arrangement of layers.Under the same condition,when C2H5OH/PEG-200 was used as the reaction medium,novel polyselenidostannates[TM(en)3][Sn(Se4)3](TM=Mn(15),Fe(16),Zn(17),Ni(18))were successfully prepared.[Sn(Se4)3]2-ion likes a petal shape in which three chelating ligands Se42-ions are coordinated to the same Sn4+ ion.In compounds 15-18,all of the SnSe4 rings in the[Sn(Se4)3]2-anion are in half-chair conformation.The photocatalytic degradation of the organic dye methylene blue(MB)by compounds 11,12,15 and 16 was studied under visible light irradiation.In contrast,compound 11 and 12 showed higher photocatalytic performance than 15 and 16,and the photodegradation rate of MB within 2.5 h was 86.5%and 82.8%respectively.Under the same condition,the photocatalytic degradation rates of MB by 15 and 16 were 60.1%and 71.5%,respectively.The PXRD test showed that the residues of compounds 11 and 15 after thermal decomposition at 500? were SnSe2/MnSe(SM1 and SM5),and the residues of compounds 12 and 16 were SnSe2/FeSe(SF2)and SnSe2/Fe3Se4(SF6),respectively.The experimental results show that under the same condition,when SM1,SF2,SM5 and SF6 are used as photocatalysts,almost all MB are degraded after visible light irradiation for 2.5 h,and the degradation rate reaches nearly 100%.The thermal decomposition residues SM1,SF2,SM5 and SF6 have higher catalytic activity than their precursors before thermal decomposition.Compounds 11,12,15 and 16 are excellent precursors for the preparation of TM-Sn-Se three-phase high efficiency catalysts.3.(a)In the study of the synthesis method of TM/As/S(TM=Co,Cr)reaction system,novel members of transition metal complexes with thioarsenate ligands,[Co(peha)][Co(As3S3)2](19),[Co(trien)(AsS3)](20),[Cr(trien)(AsS3)](21)and[Cr(en)2(AsS3)](22)were successfully prepared by hydrothermal method or solvothermal method in polyamines.The structural features of compound 19 is significantly different from 20-22.In the[Co(As3S3)2]2-anion cluster structure of compound 19,the As3S3 unit simultaneously uses As and S atoms to coordinate with Co2+ions.In compounds 20-22,AsS3 only uses S atoms to coordinate with Co3+or Cr3+ions.(b)In the study of the synthesis method of the Mn/As/S reaction system,an attempt was made to add a highly polar alkaline solvent(N2H4)into different chelating amine solvents,and a series of hydrazine hybrid multidimensional Mn(II)-thioarsenates[Mn(en)3]n[(N2H4)2Mn6(?6-S)(?-N2H4)2(?3-AsS3)4]n(23),[N2H5]n[?Mn(?-N2H4)2(?-AsS4)?·0.5en]n(24),[Mn(?-trien)?Mn2(?-N2H4)(?3-AsS3)?2]n(25),[?Mn(N2H4)?2(?-N2H4)2?Mn(?-N2H4)2(?-AsS3)2?]n(26),[Mn3(?-N2H4)6(?3-AsS4)(?2-AsS4)]n(27),[Mn(NH3)6]n[{Mni(NH3)(?3-AsS4)}2]n(28)were synthesized successfully by hydrazine-solvothermal method.Different coordination modes of ?-AsS3??-AsS4 and ?-N2H4 bridging ligands to Mn(II)in compounds 23-28 results to formation of Mn-As-S polymer from 1-D to 3-D structure compounds,this in turn affects the interaction between Mn(II).The magnetic properties of the compounds 23,24 and 25 were tested and analyzed.For 23,the 1/?m vs.T curve in the temperature range 100-300 K obeys the Curie-Weiss law with C?5.42 cm3 K mol-1 and ?=-126.45 K.For 24 and 25,the I/?m vs.T curve in the temperature range 50-300 K obeys the Curie-Weiss law with C=4.51 cm3 K mol-1,?=-19.85 K for 24,and C=4.46 cm3 K mol-1,?=-7.47 K for 25.From the analysis of their magnetic susceptibility curves of ?m and ?mT vs.T,it was found that antiferromagnetic(AF)interactions existed in both compound molecules.Compound 23 displays stronger antiferromagnetic coupling interaction than that of compound 24.4.Compounds 1-28 were determined by X-ray single crystal diffractometer.And these compounds were characterized via infrared spectrometer and elemental analyzer.The thermal stability,light absorption,photocatalytic properties,and magnetic properties of the compounds were measured.