Theoretical and DFT Study of Atypical Pentanuclear [( i Pr 3 P)Ni] 5 H n ( n = 4, 6, 8) Clusters: What are the Rules?

• Published in: Inorganic chemistry 2023-12, Vol.62 (51), p.20888-20900
• Main Authors: Liu, Junyang, Sum, Kethya, Groizard, Thomas, Halet, Jean-François, Johnson, Samuel A
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c03335

The structure, bonding, and properties of a series of atypical pentanuclear nickel hydride clusters supported by electron-rich Pr P of the type [( Pr P)Ni] H ( = 4, 6, 8; , , ) and their anionic models where Pr P are substituted by H ( , , ) were investigated by density functional theory (DFT) calculations. All clusters were calculated to adopt a similar square pyramidal core geometry. Calculations indicate singlet ground states with small singlet-triplet gaps for and , similar to previously reported experimental values. Molecular orbital theory description clusters were investigated using the simplified model complexes [HNi] H ( = 4, 6, 8; , , ). The results show that there are three skeletal electron pairs (SEPs) in . The addition of two molecules of H to form and results in the partial or full occupation of two degenerate MOs ( set) that give two SEPs and one SEP, respectively. Indeed, the occupation of these low-lying weakly antibonding orbitals governs the multielectron chemistry available for these clusters and plays a role in their unique reactivity.