Table 1 The constants used in the calculations for heteroligand complexes

log β₀₁₁ = 6.50 (LH)

Protonation constant of MCCh [13, 14]

log β₀₁’₁ = 9.96 (L′H)

The first protonation constant of GO for the OH⁻ group, determined under the conditions of the current experiment

log β₀₁’₂ = 12.60 (L′H₂)

The second protonation constant of GO for the COO⁻ group, determined under the conditions of the current experiment

log β_00-1 = − 13.77 (H⁻¹)

pK_w

log β_10-1 = − 11.70 (MH⁻¹)

Hydrolysis constant of Mg²⁺ [15]

log β₁₁₀ = 3.29 (6) (ML)

The value obtained from previous tests for the system MCCh–Mg²⁺ [16]

log β₁₁₁’ = 14.0 (MLL’)

In this case, it was assumed that the central atom Mg²⁺ is surrounded by the ligand molecule L-MCCh and ligand L′-GO