Hydrothermal synthesis and magnetic properties of novel Mn(II)and Zn(II)materials with thiolato-carboxylate donor ligand frameworks

摘要

The hydrothermal reaction of thiosalicylic acid,(C_6H_4(CO_2H)(SH)-1,2)with manganese(III)acetate leads to formation of the coordination solid[Mn_5((C_6H_4(CO_2)(S)-l,2)_2)_4(mu_3-OH)_2](1)via a redox reaction,where resulting manganese(II)centres are coordinated by oxygen donor atoms and S-S disulfide bridge formation is simultaneously observed.Reaction of the same ligand under similar conditions with zinc(II)chloride yields the layered coordination solid[Zn(C_6H_4(CO_2)(S)-l,2)](2).Hydrothermal treatment of manganese(III)acetate with 2-mercaptonicotinic acid,(NC_5H_3(SH)(CO_2H)-2,3)was found to produce the 1-dimensional chain structure[Mn_2((NC_5H_3(S)(CO_2)-2,3)_2)_2(OH_2)4]-4H_2O(3)which also exhibits disulfide bridge formation and oxygen-only metal interactions.Compound 3 has been studied by thermogravimetric analysis and indicates sequential loss of lattice and coordinated water,prior to more comprehensive ligand fragmentation at elevated temperatures.The magnetic behaviour of 1 and 3 has been investigated and both exhibit antiferromagnetic interactions.The magnetic behaviour of 1 has been modelled as two corner-sharing isosceles triangles whilst 3 has been modelled as a 1-dimensional chain.