Author(s) :

Laurent Ngalamulume Lumu, Christian Tshikala Mukeba, Jules Tshishimbi Muya.

Volume/Issue :

Abstract :

Polyhedral oligomeric silsesquioxanes (POSS) represent a fundamental class of organic–inorganic hybrid nanostructures. However, a comprehensive understanding of how peripheral electronic effects modulate the intrinsic stability of the inorganic cage remains lacking. Herein, a systematic Density Functional Theory (DFT) study of octafunctionalized derivatives Si₈R₈O₁₂ (R = Cl, CF₃, OH, NH₂, COOH, and OCH₃) was performed at the B3LYP/6-311+G(d) level. Structural parameters, electronic descriptors, and thermodynamic stabilities were systematically evaluated. Strong electron-withdrawing groups (Cl, CF₃, and COOH) induce framework contraction and enhance thermodynamic cage stabilization. HOMO-LUMO gaps, isodesmic stabilization energies (ISE), and $\text{NICS}(0)$ values demonstrate high electronic robustness and non-aromatic character. High-level G3B3 thermochemical calculations on Si₈H₈O₁₂, Si₈Li₈O₁₂, and Si₈F₈O₁₂ establish the stability order: Si₈F₈O₁₂ > Si₈H₈O₁₂ > Si₈Li₈O₁₂. These insights offer precise design guidelines for tailoring novel functional hybrid materials.

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