Flexible and redox-active coordination polymer: Control of the network structure by pendant arms of a macrocyclic complex

The coordination polymer {[Ni(C₂₀H₃₂N ₈)]₂[TCM]}.5DMF. 8H₂O (1) has been assembled from a Ni^II macrocyclic complex that contains two pyridyl pendant arms, [Ni(C₂₀H₃₂N₈)]- (ClO₄) ₂, and sodium tetrakis[4-(carboxyphenyl)oxamethyl]- methane (Na4TCM) in DMF/water. The X-ray structure of 1 reveals that the pyridyl pendant arms in the macrocyclic complex play a crucial role in determining the network structure through the π-π interactions. Compound 1 forms doubly catenated rhombic grids that generate 1D channels. It exhibits flexible behavior upon desorption/resorption and exchange of organic guest molecules as well as temperature change. Solid 1 is redox active due to the incorporated Ni ^II macrocyclic species, and reacts with Pd(NO₃) ₂ dissolved in acetonitrile at room temperature to produce small Pd nanoparticles [(2.9±0.4) nm in diameter] in the channels in the absence of extra reducing or capping agents.