PChem Seminar – Iaroslav Gureev

About the event

Speaker: Iaroslav Gureev

Group: Dr. Ivan Popov Group

Title: Orbital Localization–Driven Disruption of Peripheral Bonding in Valence-Isoelectronic B12– Clusters.

Abstract

Electron deficiency of boron enables diverse structural motifs and unconventional bonding. In the bulk, it forms complex crystalline polymorphs based on B₁₂ icosahedra. In contrast, gas-phase boron clusters remain planar or quasi-planar up to B₄₂⁻.^1,2 Although aluminum is valence-isoelectronic with boron, small aluminum clusters become three-dimensional as early as Al₆, due to reduced effective s–p hybridization and greater electron localization in aluminum.^3,4

2D-like anionic boron clusters are always characterized by strong peripheral 2c–2e σ bonds and delocalized interior σ/π networks. Substituting B with heavier Group 13 elements (Al, Ga, In, Tl), which favor greater electron localization, is expected to disrupt the peripheral bonding and promote 3D structures. Combined photoelectron spectroscopy and ab initio studies show that even a single B→Al substitution can significantly distort parent boron frameworks.^5,6 Nevertheless, some Al–B clusters retain the original geometry even after double substitution, with Al atoms preferentially occupying peripheral sites.^7,8

In my talk, I will present a theoretical study of valence-isoelectronic substitutions in the quasi-planar B₁₂⁻ cluster, systematically examining how heavier Group 13 dopants (Al, Ga, In) affect its geometric and electronic structure. To date, only AlB₁₁⁻ cluster has been explored, retaining the B₁₂⁻ framework and localized peripheral 2c–2e σ bonding.⁹ Specifically, this study investigates: (i) how many Al substitutions are required to disrupt peripheral bonding in B₁₂⁻; (ii) the impact of heavier Ga and In substitution in the B₁₂⁻ framework; (iii) cooperative effects in mixed-metal substitutions; and (iv) electronic structure changes associated with deviations from the B₁₂⁻ archetype.

References

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(3)        Rao, B. K.; Jena, P. J. Chem. Phys. 1999, 111 (5), 1890–1904.

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(7)        Wen, L.; Li, G.; Yang, L.-M.; Ganz, E. Eur. Phys. J. D 2020, 74 (11), 223.

(8)        Gu, J.; Wang, C.; Cheng, Y.; Zhang, L.; Yang, X. Comput. Theor. Chem. 2014, 1049, 67–74.

(9)        Romanescu, C.; Sergeeva, A. P.; Li, W.-L.; Boldyrev, A. I.; Wang, L.-S. J. Am. Chem. Soc. 2011, 133 (22), 8646–8653.