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The spin transition in the reactions of the derivatives of imidazo[1,2-a]pyrazin-3(7H)-one with a triplet molecular oxygen is examined by the geometry optimization and the electronic matrix elements for spin-orbit coupling (SOC) is evaluated by using the full Pauli-Breit SOC operator. An optimal state is present for the suppression of SOC in the charge-transfer-induced luminescence (CTIL) for the peroxide, which is related with the ability of a substituent to donate an electron.

The first synthesis of cyclic endiamino peptides, including 2-(1H)-pyrazinone and the endiamino building blocks is reported. The preparation of endiamino hexapeptide, trimeric nonapeptide, tetrapeptide, octapeptide demonstrate the possibility of incorporation of the endiamino functionality in cyclic peptides, with the endiamino group replacing the lactone of depsipeptides, further reducing the conformational freedom.