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

Dalton Transactions Pub Date: 2008-08-26 DOI: 10.1039/B806619A

Abstract

Three homochiral layered complexes, [Cu3(R-chea)2(N3)6]n (1), [Cu3(S-chea)2(N3)6]n (2) (chea = 1-cyclohexylethylamine) and [Cu3(S-phpa)2(N3)6]n (3) (phpa = 1-phenylpropylamine), and three novel cluster-based coordination polymers, [Cu6(1,2-pn)4(N3)12]n (4) (1,2-pn = 1,2-diaminopropane), {[Cu8(en)4(N3)16]·H2O}n (5) (en = ethylenediamine) and [Cu6(N-Ipren)2(N3)12]n (6) (N-Ipren = N-isopropylethylenediamine), have been synthesized by the self-assembly reactions of Cu(NO3)2·3H2O, 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 [Cu6(N3)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.

Graphical abstract: Cluster-based copper(ii) coordination polymers with azido bridges and chiral magnets
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