Linkage isomerism occurs in complexes with ambidentate ligands. For instance, thiocyanate ligand (NCS⁻) can bind through nitrogen (M–NCS) or sulphur (M–SCN), illustrated by complexes like [Co(NH₃)₅(NO₂)]Cl₂.
What is linkage isomerism, and provide an example involving the thiocyanate ligand in coordination compounds?
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Linkage isomerism occurs when the same ligand can coordinate to the metal center through different atoms. An example involves the thiocyanate (NCS⁻) ligand. In one linkage isomer, thiocyanate coordinates through nitrogen (N), forming isothiocyanato, while in the other, it coordinates through sulfur (S), forming thiocyanato. For instance, in [Co(NH₃)₅(NCS)]²⁺, thiocyanate is coordinated through nitrogen, while in [Co(NH₃)₅(SCN)]²⁺, it is coordinated through sulfur. The interchange of binding atoms influences the isomer’s stability and reactivity. Linkage isomerism is crucial in understanding the diversity of coordination compounds with the same overall composition but distinct ligand binding modes.