# Neighboring Alkali Cations as an Efficient Strategy for N2 Activation: A DFT Analysis

## TL;DR

This paper explores how alkali cations can help activate nitrogen gas using theoretical analysis, offering a new strategy for efficient nitrogen fixation.

## Contribution

The study identifies distinct activity regimes and highlights the role of non-covalent interactions in N2 activation.

## Key findings

- Three distinct activity regimes were identified based on cation effects on N2 activation.
- Group II-A cations, especially Mg2+, showed superior activity at specific distances.
- Theoretical insights suggest a synergistic approach combining covalent and non-covalent interactions for efficient N2 activation.

## Abstract

Nitrogen gas is one of the most abundant resources on Earth, serving as a fundamental component in both biological and industrial processes. Nevertheless, this simple molecule can only be activated by a limited group of microorganisms in nature. Significant efforts have been devoted to replicating this biological activity using metalorganic approaches. However, it is becoming increasingly evident that non-covalent interactions, particularly ionic interactions, can further enhance catalytic reactions. In this work, the effect of alkali and alkaline-earth cations on dinitrogen activation was assessed using Density Functional Theory (DFT) at distances ranging from 2 to 10 Å. This analysis revealed three distinct activity regimes. In Case I, the polarization of the N2 molecule is the primary driving force; in Case II, the polarization effect is less pronounced; and in Case III, electrostatic interactions dominate, enhancing electron delocalization within the N2–Mn+ system. Among the various cations, those belonging to group II-A are particularly noteworthy due to their high ionic potential and polarizing power, with Mg2+ standing out for its superior activity at an N2–Mg2+ distance of 2.7 Å. Consequently, these theoretical insights can serve as a guiding strategy for designing efficient N2-activating complexes that integrate covalent and non-covalent interactions synergistically.