DFT Study of the Interaction of Trialkylamines with Ni 4 -Clusters

This research studies binding of trialkylamine derivatives to the multiplicity optimized Ni4-clusters using theoretical approaches. The goal is to understand the interaction behavior on the metal surface and provide some key points important to the corrosion problems. The results show that trialkylamine derivatives are able to establish N–Ni bond through either short or long diagonal of Ni4-cluster. Of the studied triethylamine, tripropylamine, and tributylamine, the last derivative in series shows highest binding energy. TAAs/Ni4-cluster complexes with M=5 show special electronic charge transfer that stabilizes the complex. According to this analysis for natural charges, therefore, the nature of metal–ligand (e.g., N–Ni) interactions that underlay TAAs/Ni4-cluster complexes can be elucidated. Possible correlation between interaction strength, polarizability, nitrogen’s atomic charge and the orbitals energy gaps is also investigated. The results of natural bond orbital analysis explore the strong charge transfer from lone pair of nitrogen atom to σ∗ and n∗ orbitals of the clusters. The trialkylamines in this work are weaker corrosion inhibitor on the small nickel cluster than the previously studied aromatic nitrogen containing compounds like pyridine.