Anion-π interaction stitching 2-D layers formed by self-assembly of cations of a mononuclear copper(II) complex: synthesis, crystal structure and magnetism of [Cu(OAc)(2,2'-dypam)2](ClO4) [HOAc = acetic acid, 2,2'-dypam = 2,2'-dipyridylamine].

A mononuclear Cu(II) compound [Cu(OAc)(2,2'-dypam)2](ClO4) (1), where HOAc and 2,2'-dypam are, respectively, acetic acid and 2,2'-dipyridylamine, has been synthesized and characterized by single crystal X-ray diffraction analysis. The cations of 1 link by N-H ··· O hydrogen bonds to form infinite 1-D zig-zag chains, which run along the b axis. Two adjacent chains along the c axis are joined by C-H ··· O hydrogen bonds to form a 2-D network. These 2-D layers are further bridged by perchlorate anions via weak anion-π interactions that act as a supramolecular glue to build the 3-D supramolecular network. Variable temperature (1.7-300 K) magnetic measurements revealed very weak intermolecular antiferromagnetic interactions at temperatures below 20 K between Cu(II) ions mediated by hydrogen bonds, C-H ··· π and π ··· π interactions. At temperatures ≥20 K, susceptibility data corresponds to isolated Cu(II) ions, indicating that the weak interactions affect the magnetism of 1 only at very low temperatures. [ABSTRACT FROM AUTHOR]