Cu(II) coordination polymers incorporating 3-aminopyridine and flexible aliphatic dicarboxylate ligands: Synthesis, structure and magnetic properties

Abstract

The synthesis, structural chemistry and magnetic properties of a series of new Cu(II) polymers with α,ω-dicarboxylic acids (sebacic (H 2seb), suberic (H 2sub), succinic (H 2suc) and adipic (H 2adip)) and 3-aminopyridine (3-apy) are described: [Cu(Hsub) 2(3-apy) 2·2CH 3OH] n ( 1); [Cu(Hseb) 2(3-apy) 2·4CH 3OH] n ( 2); [Cu(Hsuc) 2(3-apy) 2] n ( 3); [Cu(adip)(3-apy) 2] n · n(H 2adip) ( 4). All four compounds feature a bis-monodentate bridging mode of the coordinated dicarboxylate moiety. Compounds 1 and 2 exhibit linear chains, whereas compound 3 shows two-dimensional structure. The 3-apy ligand acts as terminal ligand in 1– 3. Compound 4 contains a doubly deprotonated adipate (adip 2−) that connects Cu centers into linear chains. Additionally, 3-apy acts as a bridge in 4, resulting in the formation of parallel two-dimensional layers distant enough to host neutral molecules of adipic acid. Magnetic susceptibility measurements of compounds 1 and 3 show Curie law behavior indicating that the S = 1/2 Cu(II) spin carriers are magnetically well isolated by the dicarboxylate ligands.