Jaffe' reaction products.

Polarographic and spectrophotometric studies of the interaction of creatinine with alkaline picrate have been undertaken in sodium hydroxide concentrations ranging between 0.95 and 4.5 mol/l. Red colored 1:1 and orange colored 2:1 creatinine-picrate complexes readily formed along with orange colored 1:1:1 creatinine-picrate-hydroxide complexes. The red and orange colored complexes were easily identified by their corresponding absorption maxima near 490 nanometers and 390 nanometers, respectively. Alkaline picrate polarograms showed three well-defined nitro group reduction waves with approximate half-wave potentials of -0.60 volts, -0.77 volts, and -0.91 volts. Increased concentrations of hydroxide and/or creatinine resulted in a decreased diffusion current for reduction waves 1-3 and the appearance of a fourth reduction wave, with an approximate half-wave potential of -1.24 volts. Further increases in base and/or creatinine concentration resulted in the disappearance of reduction waves 1-3, with only reduction wave 4 remaining. Based upon the experimental data, a tri-nitro anion structure has been assigned for the 2:1 complex.