“…Techniques such as surface enhanced raman spectroscopy (SERS), , infrared (IR) spectroscopy, , nuclear magnetic resonance (NMR) spectroscopy, , X-ray diffraction analysis (XRD), − and density function theory (DFT) calculations ,− have been used to differentiate the various conformations of hist in solid-state, solution, and gas-phase circumstances. But in solution at room temperature, H-bonding is transient so that multiple conformations coexist and can be challenging to differentiate using ensemble measurements. , …”