Why are very low temperatures used to study carbenes by matrix isolation?

Carbenes are highly reactive molecules that typically exist only as transient intermediates during chemical reactions. Because they possess high energy content, they are prone to rapid further reaction if not stabilized.12

Matrix isolation is used to study these species because it allows scientists to prevent the resulting carbene from undergoing further chemical change. By performing the photolysis of precursors at very low temperatures within an unreactive solid medium—or matrix—the carbene can be trapped and preserved. For instance, methylene has been generated in a crystalline matrix of inert gas cooled to the boiling point of helium, where it persists long enough for detailed study.2