Quantum-chemical simulation of nanoparticle formation from copper carboxylates

The DFT B3LYP/6-31G** quantum-chemical method has been employed to study the structure of copper carboxylate complexes and clusters composed of copper atoms and carboxylate molecules. Peculiarities of nanoparticle formation from the carboxylates under the conditions of their clustering have been considered. It has been established that the growth of Cu(1+) complexes begins from structures containing three copper atoms, while a complex containing two copper atoms is thermodynamically disadvantageous. The complexation is accompanied by the passage from a bidentate-cyclic carboxylate-metal coordination, which is typical of a monomeric salt, to a bidentate-bridging coordination. As the size of a complex increases, the energy of the attachment of a salt molecule and a metal atom to the growing nanoparticle increases, tending to some limit. It has been shown that nucleation of a nanoparticle may be accompanied by an additional stabilization via the direct coordination of a metal atom with a carboxyl group. The direction of the process to the formation of either metal nanoparticles or mixed clusters is determined by the gain in the Gibbs free energy.