Synthesis, crystal structure and magnetic properties of a two-dimensional cyanide-based heterometallic coordination polymer with cationic piperazinium ligands: poly[aquatetra-μ₂-cyanido-κ⁸C:N-dicyanido-κ²C-(piperazinium-κN⁴)cobalt(III)copper(II)]

Abstract

Cyanide as a bridge can be used to construct homo- and heterometallic complexes with intriguing structures and interesting magnetic properties. These ligands can generate diverse structures, including clusters, one-dimensional chains, two-dimensional layers and three-dimensional frameworks. The title cyanide-bridged Cu(II)-Co(III) heterometallic compound, [Cu(II)Co(III)(CN)6(C4H11N2)(H2O)]n, has been synthesized and characterized by single-crystal X-ray diffraction analysis, magnetic measurement, thermal study, vibrational spectroscopy (FT-IR) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS). The crystal structure analysis revealed that it has a two-dimensional grid-like structure built up of [Cu(Hpip)(H2O)](3+) cations (Hpip is piperazinium) and [Co(CN)6](3-) anions that are linked through bridging cyanide ligands. The overall three-dimensional supramolecular network is expanded by a combination of interlayer O-H...N and N-H...O hydrogen bonds involving the coordinated water molecules and the N atoms of the nonbridging cyanide groups and monodentate cationic piperazinium ligands. A magnetic investigation shows that antiferromagnetic interactions exist in the title compound.

Alkoxy-Bridged Dicopper(II) Cores Meet Tetracyanonickelate Linkers: Structural, Magnetic, and Theoretical Investigation of Cu/Ni Coordination Polymers

“…Systemic research has been conducted on the coordination polymers driven by the [M­(CN) x ] (M = Fe, Co, Ni, Cu, or Pd; x = 4 or 6) linkers . In this context, cyanometalate anions including [Fe­(CN) 6 ] 3– , − [Co­(CN) 6 ] 3– , ,− [Ni­(CN) 4 ] 2– , − or [Pd­(CN) 4 ] 2– ,, are particularly interesting given their ability to connect to other metal centers through a different number of cyanide groups, producing magnetically attractive heterometallic systems. However, the use of square-planar building blocks such as tetracyano­nickellate­(II) anions in the design of heterometallic systems containing multidentate aminoalcohols as stabilizing ligands has been underexplored.…”