Characterization of intermolecular interaction between two substances when one substance does not possess any characteristic peak

• A method is proposed to probe intermolecular interaction of two solutes where a solute has no peak.
• 2D asynchronous spectrum can be used reliably to characterize intermolecular interactions.
• This approach is proved to be applicable for real chemical systems.

We explore whether it is possible to use 2D correlation spectrum to characterize intermolecular interactions between two solutes dissolved in the same solution when one substance does not possesses any characteristic peak. We demonstrate that the interaction can be manifested by characteristic cross peaks in 2D asynchronous correlated spectrum. The above cross peaks reflect the subtle spectral variations on the characteristic peak of another solute under intermolecular interaction. On the other hand, 2D synchronous spectrum is not suitable to characterize intermolecular interaction since the cross peaks contain irremovable interfering parts. The terbium-chloride/benzamide/methanol system is used to demonstrate that this approach is applicable in the real chemical system.