Supramolecular solid-state architectures constructed from 4,4′-bipyridine-N,N′-dioxide and dicyanamido tectons. Synthesis and crystal structures of [M(bpno) 2{N(CN) 2} 2(H 2O) 2] (M=Co, Mn) and [Cu(bpno){N(CN) 2} 2(H 2O)

Abstract

The reaction between transition metal salts, M(ClO 4) 2·6H 2O (M=Co, Mn, Cu), sodium dicyanamide, NaN(CN) 2, and 4,4′-bipyridine-N,N′-dioxide, bpno, leads to three new complexes: [Co(bpno) 2{N(CN) 2} 2(H 2O) 2] 1, [Mn(bpno) 2{N(CN) 2} 2(H 2O) 2] 2, and [Cu(bpno){N(CN) 2} 2(H 2O)] 3. In the three compounds, the N(CN) 2 − ions act as monodentate ligands through one of the CN groups. Compounds 1 and 2 are isomorphous. Both bpno molecules are terminal ligands. The metal ions, cobalt(II) and manganese(II), display an octahedral stereochemistry and are located on an inversion center. In compound 3, the bpno molecules act as bridging ligands and support the formation of infinite chains. The copper(II) ions are pentacoordinated. The packing diagrams of the three compounds reveal interesting supramolecular solid-state architectures. Compounds 1 and 2 are two-dimensional hydrogen bonded polymers, which are formed by the interaction of the bpno and dicyanamido ligands with the aqua ligands of neighboring [M(bpno) 2{N(CN) 2} 2(H 2O) 2] units. The crystal structure of 3 consists of infinite chains of copper(II) ions connected through the bpno bridges. The distance between the copper atoms within the chain is 12.00 Å. The copper(II) ions exhibit a distorted square-pyramidal stereochemistry. The apical position is occupied by a water molecule. Hydrogen bond interactions between the aqua ligands and the terminal dicyanamido ligands lead to a complex 2-D structure.