Syntheses, Crystal Structures, Magnetic Behaviours, and Thermal Properties of Three Hydrogen-Bonding Networks Containing Dicyanamide and 4-Hydroxypyridine

Abstract EN

Three new dicyanamide-bridged polymeric complexes of {[Mn(dca)2(L)2]·2H2O}n (1), {[Cd(dca)2(L)2]·2H2O}n (2), and {[Co(dca)2(L)2]2(L)}n (3) (dca = dicyanamide, L = pyridinium-4-olate) have been synthesized and structurally characterized.

In the three compounds, the protons of hydroxyl groups of 4-hydroxypyridine transfer to pyridyl nitrogen atoms.

Compounds 1 and 2 are isomorphous forming one-dimensional [M(dca)2(L)2]n chains where metals are connected by double dca anions.

These one-dimensional chains are extended into two-dimensional layers through weak C–H⋯N hydrogen bonds.

Further, these layers are assembled into a three-dimensional supramolecular network through N–H⋯O, O–H⋯O hydrogen bonds.

Complex 3 is a coordination layer of (4, 4) topology with octahedral metal centers linked by four single μ1,5-bridges.

These layers are interlocked by N–H⋯O, O–H⋯O hydrogen bonds from coordinated water molecules and free L molecules, which leads to a three-dimensional supramolecular architecture.

The variable temperature magnetic susceptibilities measurement of compounds 1 and 3 shows the existence of weak antiferromagnetic interactions between the metal centers.

The thermogravimetric analyses of the compounds 1–3 are also discussed.