The Syntheses, Structures And Properties Of Cu Or Ag Complexes With Triazolates And Pyrazolates

In this paper, we designed and synthesized five organic ligands, containing two triazolatesand three pyrazolates. Ten complexes based on these ligands have been synthesized successfully,which were characterized by IR spectroscopy, elemental analyses,1H NMR, thermogravimetricanalyses, power X-ray diffraction and X-ray single-crystal diffraction; moreover, their thermalstability, magnetic property and biological activity were also studied.The five organic ligands and their abbreviations are as follows:4-amino-3,5-bis(hydromethyl)-1,2,4-triazole (H2ahmt)3,5-bis(hydroxylmethyl)-1,2,4-triazole (H3hmt)4-methyl-3,5-diphenylpyrazole (MePh2pz)4-ethyl-3,5-diphenylpyrazole (EtPh2pz)4-benzyl-3,5-diphenylpyrazole (BnPh2pz)The ten complexes and their abbreviations:[Ag4(H2ahmt)6(NO3)2](NO3)2(1)[Ag4(H2ahmt)6(ClO4)2](ClO4)2(2)[Ag4(H2ahmt)6(BF4)2](BF4)2(3)[Cu(Hhmt)]n(4)[Ag(MePh2pz)]3·1/2CHCl3(5)[Cu(MePh2pz)(CH3O)]6·CH2Cl2(6)[Ag(EtPh2pz)]3(7)[Cu(EtPh2pz)(CH3O)]6·CH2Cl2(8)[Ag(BnPh2pz)]3(9)[Cu(BnPh2pz)]3(10)The ten complexes are classified into two categeries according to the ligands:1. The complexes based on1,2,4-triazole with Cu(II) or Ag(I): a Tetranuclear complexes:[Ag4(H2ahmt)6(NO3)2](NO3)2(1),[Ag4(H2ahmt)6(ClO4)2](ClO4)2(2) and [Ag4(H2ahmt)6(BF4)2](BF4)2(3), all of which consist of four two-coordinated Ag atoms and six μ2-N1,N2bridged triazolates, featuring typical Ag4tz6-b clusters. b Coordination polymer:[Cu(Hhmt)]n(4)exhibits a (3,3)-connected net, in which each deprotonated triazolato ligand adopts μ3-N1,N2,N4 and μ2-O1,O2bridging mode; each Cu(II) is chelated by O and N atoms to form a srs net with(103·103) topology notation.2. The complexes formed by pyrazolates with Cu(I), Cu(II) or Ag(I): a0D cyclic trinuclearcomplexes—M3(μ-L)3: Complexes5,7,9and10belong to this type; each deprotonatedpyrazolate acts as a μ2-N1,N2bridging ligand coordinated with Cu(I) or Ag(I) to form a stabletriangular structure. b Hexanuclear crown complexes:[Cu(MePh2pz)(CH3O)]6·CH2Cl2(6) and[Cu(EtPh2pz)(CH3O)]6·CH2Cl2(8) are both hexanuclear complexes; in the presence of MeOH,each Cu(II) is coordinated by two OMe and two deprotonated pyrazolates so hexanuclearmetallamacrocyclic crown structure is prone to be formed from trinuclear complex, which ismore stabler than the latter.From our work, we can draw several conclusions:1. The structures of Ag(I) adducts of4-amino-3,5-disubstituted-4H-1,2,4-triazoles are notonly affected by the size of3,5-substituents, but also the structures of those substituents. Wehave recently reported the synthesis and structures of a series of tetranuclear Ag(I) clusters. Andthree main effects upon the structures of Ag(I) clusters are found: changing the ligand’ssubstituents, changing the anions and changing the solvent.2. Cu/1,2,4-triazoles complexes are usually prepared in the presence of NH3·H2O orhydrothermal reaction, in which1,2,4-triazoles are in the form of1,2,4-triazoles anions. Thedeprotonated triazoles can build more complicated3D polymers, which are mainly Cu(I)complexes. In the synthesis of4, we used water as the solvent, with higher temperature; as aresult, not only the N-H groups of1,2,4-triazoles but also the O-H groups of thehydroxylmethyl are deprotonated, during which the coordination ability of O is improved. EachCu(II) is coordinated by O and N atoms to form a3D network.3.3,5-disubstituted-4H-1,2,4-triazoles are deprotonated easily in the presence of NH3·H2O,with which Ag(I) complexes can be obtained. In the reaction of3,5-bis(hydromethyl)-1,2,4-triazole with silver(I) ions in presence of a base like NaOH or Et3N usuallyaffords intractable white solid, which is not suitable for X-ray single crystal diffraction. So wecan not confirm the structure of this complex, which is a difficulty to deal with.4. During the research of Cu/4-substituted-3,5-diphenylpyrazole complexes, it is worthy tonote that some Cu(I)4-substituted-3,5-diphenylpyrazole complexes are unstable in solution,which can be oxidized to Cu(II) complexes; especially in MeOH solution, brown block crystalscan be yielded from the Cu(I) pyrazolate complexes, which indicates Cu(II) complexes of hexanuclear structures are relatively stable.