Tuning the Structure and Magnetism of Azido-Mediated CuIISystems by Coligand Modifications

Through the use of a series of structurally related benzoates bearing different substituents as coligands, three new azido-copper compounds, [Cu(benzoate)(N(3))](n) (1), [Cu(2-methyl-benzoate)(N(3))](n) (2), and [Cu(1-naphthoate)(N(3))](n) (3), have been successfully obtained and structurally and magnetically characterized. Single-crystal structure analyses indicated that the uncoordinating substituents in the benzoates greatly affect the structure of the complexes. Complex 1 displays isolated ferromagnetic chains with the largest Cu-N-Cu angle in known carboxylate/end-on-azido mixed-bridged copper systems, while complexes 2 and 3 were 2D coordination polymers, containing mu-(1,1,3,3) and mu-(1,1,3) bridging azides and exhibiting new azido-copper networks with (4(4)) and (4.8(2)) topologies, respectively. Furthermore, 2 was a chiral complex obtained through spontaneous resolution. In the low-temperature range, both 2 and 3 showed spontaneous magnetization with characteristics of soft ferromagnetic magnetism with phase transition temperatures of 13 and 10 K, respectively.