We devoted the initial stage of the calculations to an assessment of the effect of solvent and counterions on the structure and relative stability of the metal-organic clusters. On the one hand, we were interested in determining the differences between direct computations of the complexes in vacuo and computations with implicit solvent (ethanol) through the thermodynamic cycle mentioned in Sec. 2. On the other hand, in order to explore sensible aggregation and eventual nucleation routes, it is particularly relevant to determine to what extent the incorporation of explicit solvent molecules (ethanol, water) or counterions (nitrate, NO - 3 ) to the first coordination sphere of the Zn 2+ cation contributes to the stabilization of the complexes. Note that ethanol is a common solvent medium and the NO - 3 anion is a common counterion in the Zn salts used in ZIF synthesis. Water is included as zinc nitrate is usually included as the hydrated salt in synthesis mixtures.