Related Experiment Video
Updated: May 21, 2026
Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Vapochromic behaviour of M[Au(CN)2]2-based coordination polymers (M = Co, Ni)
Julie Lefebvre1, Jasmine L Korčok, Michael J Katz
1Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada. jlefebvr@ucalgary.ca
Abstract:
A series of M[Au(CN)(2)](2)(analyte)(x) coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH(2))[Au(CN)(2)](2) yielded visible vapochromic responses for M = Co but not M = Ni; the IR ν(CN) spectral region changed in every case. A single crystal structure of Zn[Au(CN)(2)](2)(DMSO)(2) revealed a corrugated 2-D layer structure with cis-DMSO units. Reacting a Ni(II) salt and K[Au(CN)(2)] in DMSO yielded the isostructural Ni[Au(CN)(2)](2)(DMSO)(2) product. Co[Au(CN)(2)](2)(DMSO)(2) and M[Au(CN)(2)](2)(DMF)(2) (M = Co, Ni) complexes have flat 2-D square-grid layer structures with trans-bound DMSO or DMF units; they are formed via vapour absorption by solid M(μ-OH(2))[Au(CN)(2)](2) and from DMSO or DMF solution synthesis. Co[Au(CN)(2)](2)(pyridine)(4) is generated via vapour absorption by Co(μ-OH(2))[Au(CN)(2)](2); the analogous Ni complex is synthesized by immersion of Ni(μ-OH(2))[Au(CN)(2)](2) in 4% aqueous pyridine. Similar immersion of Co(μ-OH(2))[Au(CN)(2)](2) yielded Co[Au(CN)(2)](2)(pyridine)(2), which has a flat 2-D square-grid structure with trans-pyridine units. Absorption of pyridine vapour by solid Ni(μ-OH(2))[Au(CN)(2)](2) was incomplete, generating a mixture of pyridine-bound complexes. Analyte-free Co[Au(CN)(2)](2) was prepared by dehydration of Co(μ-OH(2))[Au(CN)(2)](2) at 145 °C; it has a 3-D diamondoid-type structure and absorbs DMSO, DMF and pyridine to give the same materials as by vapour absorption from the hydrate.
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:42Valence Bond Theory
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
02:54Coordination Compounds and Nomenclature
02:57Coordination Number and Geometry
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...