Cu(II)-serine: D-serine and Cu(II) sulfate were dissolved in 1 M NaOH at a molar ratio 2:1:2 Dserine/Cu(II) sulfate/NaOH and stirred for 1 hour at room temperature. The solution turned deep blue as components dissolved. This solution was diluted 1:20 in ethanol and left overnight, after which thin, blue, rod-shaped crystals had formed.