Cluster-based copper(II) coordination polymers with azido bridges and chiral magnets

Three homochiral layered complexes, [Cu-3(R-chea)(2)(N-3)(6)](n) (1), [Cu-3(S-chea)(2)(N-3)(6)](n) (2) (chea = 1-cyclohexylethylamine) and [Cu-3(S-phpa)(2)(N-3)(6)](n) (3) (phpa = 1-phenylpropylamine), and three novel cluster-based coordination polymers, [Cu-6(1,2-pn)(4)(N-3)(12)](n) (4) (1,2-pn = 1,2-diaminopropane), {[Cu-8(en)(4)(N-3)(16)] center dot H2O}(n) (5) (en = ethylenediamine) and [Cu-6(N-Ipren)(2)(N-3)(12)](n) (6) (N-Ipren = N-isopropylethylenediamine), have been synthesized by the self-assembly reactions of Cu(NO3)(2) center dot 3H(2)O, NaN3 and small organic amine ligands. Their crystal structures are determined by single-crystal X-ray diffraction. Complexes 1-3 are composed of neutral 2D brick wall networks with only end-on azido bridges. Complexes 4 and 5 are 3D coordination polymers featuring copper-azido clusters and [Cu(diamine)(2)](2+) units which are linked by the azido bridges. Complex 6 is a 3D coordination framework based on the hexanuclear copper(II) clusters [Cu-6(N-3)(12)(N-Ipren)(2)]. Magnetic studies show that complexes 1-3 are interesting chiral ferromagnets with the magnetic transition temperature at ca. 5.0 K. Complexes 4 and 5 show ferromagnetic coupling in the copper-azido cluster units and antiferromagnetic interaction between neighboring units, while complex 6 shows ferromagnetic ordering at 3.2 K.