B12Fn-0(n=1–6) series when do boron double chain nanoribbons become global minima  

   We present an extensive density-functional and wave function theory study of partially fluorinated B₁₂F_n ^0/- (n = 1–6) series, which show that the global minima of B₁₂ F_n^0/- (n = 2–6) are characterized to encompass a central boron double chain (BDC) nanoribbon and form stable BF₂ groups at the corres-ponding BDC corner when n≥3, but the B₁₂ F^0/- system maintains the structural feature of the well-known quasi-planar C_3v B₁₂ . When we put the spotlight on B₁₂ F₆^0/- species, our single-point CCSD(T) results unveil that albeit with the 3D icosahedral isomers not being their global minima, C₂ B₁₂F₆ (6.1,¹A) and C₁ B₁₂ F₆^-(12.1,²A) as typical low-lying isomers are 0.60 and 1.95 eV more stable than their 2D planar counterparts D_3h B₁₂F₆ (6.7,¹A₀ ) and C_2v B₁₂ F₆^- (12.7, ²A₂ ), respectively, alike to B₁₂H₆^0/-species in our previous work. Detailed bonding analyses suggest that B₁₂F_n ^0/- (n = 2–5) possess ribbon aromaticity with s plus p double conjugation along the BDC nanoribbon on account of their total number of s and p delocalized electrons conforming the common electron configuration (π²⁽ⁿ⁺¹⁾σ²ⁿ ). Furthermore, the simulated PES spectra of the global minima of B₁₂F_n ^0/-(n = 1–6) monoanions may facilitate their experimental characterization in the foreseeable future. Our work provides new examples for ribbon aromaticity and powerful support for the F/H/Au/BO analogy.