Electronic and Raman spectroscopic studies of copper adrenalin complexes and copper induced compounds

Electronic and Raman spectra of adrenalin–copper(II) complexes and copper catalyzed compounds have been studied. Adrenalin reacts with copper(II) ion at pH 9.2 and higher to produce a very short lived violet free radical, a brown adrenochrome, a yellow conjugated salt, indolyl-indoquinone, and melanin. Results indicate that copper does not form complexes with adrenalin in basic solution. Between pH 6.5 and 8.5 adrenalin transforms into adrenochrome in presence of copper. The adrenochrome in 1.5 N hydrochloric acid produces the conjugate salt that is produced in the solution of high pH. At low pH values, between pH 4.0 to 5.5, adrenalin forms a brown complex with copper(II). Copper is entirely chelated to the phenolic groups of the amines. The complex in 1.5 N hydrochloric acid produces a black polymeric pigment.