Diverse systems, including lanthanides (Ln; from La to Lu), are attracting increasing attention, particularly in the research and development of magnetic and luminescent materials. Among versatile lanthanide-based materials, lanthanide nitride cluster fullerenes (Ln₃N@C₈₀) and bisphthalocyanines (LnPc₂) have emerged as promising candidates for advanced applications such as spintronic devices.

The formation of hybrids or dyads of carbon nanomaterials (graphene and carbon nanotubes) with LnPc₂ enhances magnetic properties due to synergy between components. The Ln₃N@C₈₀ + LnPc₂ dyads remain underexplored. So far, only different macrocycles, such as porphyrins, have been reported to crystallize endohedral fullerenes (EFs). This interaction can alter EFs' structures; however, the extent to which they can achieve this is unclear.

We performed DFT characterization to investigate structural and electronic changes in noncovalently interacting lanthanide (Ln = La, Ce, Gd, Lu) nitride cluster fullerenes and bisphthalocyanines forming Ln₃N@C₈₀ + LnPc₂ dyads. Optimized geometries, formation and frontier orbital energies, HOMO-LUMO plots, the charge and spin of Ln and N(Ln₃N@C₈₀) atoms, and spin density plots were analyzed relative to isolated Ln₃N@C₈₀ and LnPc₂.

Spin distribution is among the most influenced properties in these interactions. Changes are more evident in dyads with Ce and Gd than their La and Lu counterparts. The interaction of Ce₃N@C₈₀ and Gd₃N@C₈₀ with CePc₂ and GdPc₂ redistributes spin density, altering spin-up and spin-down electron orientations in encapsulated Ce₃N and Gd₃N clusters. This behavior could enable tuning of magnetic properties, enhancing their performance as Single-Molecule Magnets in spintronic and magnetic devices