The theoretical calculation at the M05-2X/6-311+G(d,p) level reveals that the B–B bond length in [N ₄ ₋B ₂ ₋N ₄] ²⁻ system (1.506 Å) is slightly smaller than that of typical B=B bond in B ₂H ₂ (1.518 Å). These systems interact with each M ⁺ (M = Li, Na, K) ion very strongly with a binding energy of 213.5 (Li), 195.2 (Na) and 180.3 (K) kcal/mol. Additionally, the relief of the Coulomb repulsion due to the presence of counterion, M ⁺, the B–B bond contracts to 1.484–1.488Å in [N ₄ ₋B ₂ ₋N ₄]M ₂. We have further extended our study to [N ₄ ₋B ₂ ₋N ₄ ₋B ₂ ₋N ₄] ⁴⁻ and [N ₄ ₋B ₂ ₋N ₄-B ₂ ₋N ₄ ₋B ₂ ₋N ₄] ⁶⁻ systems. The B–B bond length is found to be 1.496Å in the former case, whereas the same is found to be 1.493Å and 1.508 Å, respectively, for the two B–B bonds present in the latter one. The M ⁺ counter-ions stabilize such negatively charged systems and thus, create a possibility to design a long 1-D nanowire. Their utilities as probable hydrogen and noble gas (Ng) binding templates are explored taking [N ₄ ₋B ₂2 ₋N ₄ ₋B ₂ ₋N ₄]Li ₄ system as a reference. It is found that each Li center binds with three H ₂ molecules with an average binding energy of 2.1 kcal/mol, whereas each Ng (Ar–Rn) atom interacts with Li center having a binding energy of 1.8–2.1 kcal/mol. The H ₂ molecules interact with Li centers mainly through equal contribution from orbital and electrostatic interaction, whereas the orbital interaction is found to be major term (ca. 51–58%) in Ng-Li interaction followed by dispersion (ca. 24–27%) and electrostatic interaction (ca. 17–24%).
Volume 132, 2020
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