The Syntheses,Structures And Properties Of Transition Metal Complexes With Triazolates And Pyrazolates

In this thesis,six organic ligands,containing four triazolates and two Pyrazolates were involved.The reaction of these ligands with transition metal salts led to the successful synthesis of ten complexes,which were characterized by X-ray single-crystal diffraction,powder X-ray diffraction,thermalgravimetric analyses,elemental analyses,1HNMR and IR spectroscopy.Moreover,the properties of these complexes were investigated.The six organic ligands and their abbreviations are as follows:4-nitro-1,2,4-triazole(Hntz)1,2,4-Triazole-3,5-dimethanol,3,5-diacetate(Hdat)1,2,4-Triazole-3,5-dimethanol,3,5-dipropionate(Hdpt)1,2,4-Triazole-3,5-dimethanol,3,5-dibenzoate(Hdbt)1H-pyrazole-4-carboxylic acid,ethyl ester(Hpzac)4-chloro-3,5-diphenyl-lH-pyrazole(ClPh2pzH)The ten complexes and their abbreviations:[Cu(ntz)2(NH3)2(H2O)2](1)[Ag3(ntz)3CH3CN]n(2)[Au(ntz)NH3](3)[Ag3(dbt)2NO3]n(4)[Ag3(dpt)2NO3]n(5)[Zn2(H2hmt)2(Ac)2]H2O(6)[Cd3(H2hmt)2I4]n(7)[Ag(pzac)]3(8)[Ag(ClPh2pz)]3C4H8O(9)[Ag(ClPh2pz)]3C7H5NS(10)Those complexes are classified into three categeries on the basis of the ligands and their substituent:1.One kind of complex was formed by the connection of 3-nitro-1,2,1-triazole sand transition metal(Cu2+,Ag+ or Au+)salts.The mononuclear complex 1 was found to be a elongated octahedral structure where Cu(?)was coordinated with the ligand,NH3,H2O,The crystal seems dark blue,which reflects Jahn-Teller effect.The complex 2 is also a mononuclear complex,in which the nitro substituent in the triazolate has a strong withdrawing electron effect,resulting in only N1 coordination with Au,while the N2,N4 adjacent the nitro substituent not coordination.The complex 3,a 2-D coordination polymer,Ag(?)has stronger effect to accept electrons,resulting in all the N in the triazolate ring coordination with Ag(?).2.The complexes 4-7,were obtained from triazoles featuring ester group and transition metal(Ag+,Zn2+ or Cd2+)salts.The Ag complexes 4 and 5 eshibited the similar structure type(2-D coordination polymer),Due to the variation of the substituents in the triazoles,the featured Ag4tz4 cluster in the structure of complex 4 and 5 turn to be different.Hence,the 2-D structure of the former one revealed to be wavy and the latter is plane.Complexes 6-7,under hydro/solvothermal conditions,the hydrolysis of the ester led to rather different structure composition of complex 6 and 7.Both of them are 3-D coordination polymer.In particular,the porosity of complex 6 can reach up to 12.7%v/v,and study the adsorption performance.3.The three Ag complexes 8-10 were synthesized using Pyrazolates.The complexes are all trinuclear-Ag3(?-L)3.Intermolecular argentophilicity and weak ?acid-base interaction were found in the complex 8.Moreover by the variation of substituents in the ligangds,complex 9 and 10 were obtained.Guest molecules(i.e.tetrahydrofuran and benzothiazole)are successfully introduced,respectively.Moreover,a weak interaction between the complex(9 or 10)and guest molecule was found.From the above characterization and observation,we can draw three conclusions:1.For the formation of mononuclear complexes based on 3-nitro-1,2,4-triazole.It can be inferred that the existence of nitro could make the coordination of its adjacent N atoms hard.Owing to the strong electron withdrawing effect of nitro,the donation of electrons near N atoms becomes difficult and in turn obstructs the coordination with metal clusters.Under the hydrothermal conditions,The Ag complex 3 is a 2-D coordination polymer,Because Ag(?)has stronger effect to accept electrons,and the hydrothermal synthesis conditions,resulting in all the N in the triazolate ring coordination with Ag(?).2.3,5-bis(hydroxymethyl)-1,2,4-triazole modified by esterification,on the one hand,this can get the complex crystal effectively with Ag(?),on the other hand,this also has regulatory effect on the structure of the complex.It is difficult to obtain proper complex crystal by different synthetic methods,because when the exposed hydroxyl group may well participate in coordination with Ag+ Under the hydrothermal conditions,The modified ligand hydrolysis in the process of reaction with Zn(II)or Cd(II),fathermore,hydroxyl groups in triazoles participate in the coordination.Both of them are three-dimensional coordination polymer,the structure of complexes become more complicated and interesting.3.Under certain conditions,the reaction of pyrazoles with Ag(I)salts prefer to form trinuclear-Ag3(?-L)3;When the substituent is Cl or COOEt,pronounced?-acidity is shown in the trinuclear center.Especially the ?-acidity in the latter type of trinuclear is stronger than the former one.The ?-acid/base interaction can be generated not only between the complexes and the guest molecules,but also among the trinuclears of the complexes.Hence,during the design of such kind of trinuclear,the ?-acidity of the trinuclear should be carefully monitored in order to successfully introduce ?-basic guest molecules.