Chelating complexes

[caylayounger_2G]

I was looking at the textbook question 9C.8 and was wondering about how even though certain compounds can have multiple nitrogens it can still not act as a chelating complex? What else do we look at in terms of structure to know if something is a chelating complex? Is it just any polydentate compound with multiple donor atoms or is there more to it.

[Fatima1B]

In order to determine if a compound acts as a chelating complex, it doesn't just come to having multiple donor atoms like nitrogen. You need to consider the spatial arrangement as the donor atoms must be positioned in a way that allows them to bind to the same central metal atoms. When the geometry of the molecule doesn't support this idea then it won't be chelating complex. You also have to consider the ring formation as chelation typically involves forming a stable ring structure with the metal. It's about having multiple donor atoms and their spatial orientation relative to the central metal.