The Raman spectra of a crown complex of tris(hydroxymethyl)aminomethane

The Raman spectra of tris(hydroxymethyl)aminomethane (TRIS) and a complex o f TRIS with 18-crown-6 (crown) were recorded at various pH (10, 8.3, 7.8, a nd 3). The Raman spectrum of TRIS was close to its IR spectrum. Both proton ated and dt protonated amino groups were found to be completely involved in complex formation at equimolar concentrations of crown and TRIS. The depro tonated form of TRIS virtually did not form complexes with crown in the pre sence of the protonated form. The protonated form of TRIS formed complexes with crown in the presence and in the absence of the deprotonated form.