Spin accommodation and reactivity of nickel clusters with oxygen: Aromatic and magnetic metalloxocube Ni13O8±

Due to challenges in preparing pure metal clusters and in controlling reactions, the oxides produced by metal clusters reacting with oxygen are often different from traditional ion-molecule products in the gas phase and their reactivity pattern is also largely unveiled yet. In this work, utilizing a customized Re-TOFMS having a home-made cluster source and a flow tube reactor, we have observed the gaseous reactions of Ni-n(+/-) clusters with oxygen and found magic clusters of Ni13O8 +/- that dominate the mass distributions. By quantum chemistry calculations, we find that both Ni13O8- and Ni13O8+ clusters bear a regular cubic structure with 8 oxygen anchoring the eight angles, however, they have rather different spin accommodations. The Ni13O8- clusters have 15 unpaired spin-up electrons exhibiting cubic aromaticity and decent ferromagnetism, while the Ni13O8+ clusters take a lower-spin ground state (11 unpaired electrons), with spin-down population on the central Ni atom pertaining to ferrimagnetism. This is a class of metalloxocube clusters that hold properties of aromaticity and ferromagnetism/ferrimagnetism charcterized by a few spin electrons, which embodies the bonding nature of superatomic compounds and enables to develop cluster-genetic materials of multi-functionality.

Automated summary

This study observed the gaseous reactions of Ni-n(+/-) clusters with oxygen and identified magic clusters of Ni13O8 +/-, with quantum chemistry calculations revealing their structural and spin arrangement characteristics. The Ni13O8- clusters demonstrated cubic aromaticity and ferromagnetism, while the Ni13O8+ clusters exhibited lower-spin ground states and ferrimagnetism associated with spin-down population on the central Ni atom. This class of metalloxocube clusters hold properties of aromaticity and ferromagnetism/ferrimagnetism, leading to the development of cluster-genetic materials with multi-functionality.