Halogen Bonding and Chalcogen Bonding in 4,7-Dibromo-5,6-dinitro-2,1,3-benzothiadiazole

Abstract

An organic solid, 4,7-dibromo-5,6-dinitro-2,1,3-benzothiadiazole, has been designed to serve as an illustrative example to quantitatively evaluate the relative merits of halogen and chalcogen bonding in terms of charge density features. The compound displays two polymorphic modifications, one crystallizing in a non-centrosymmetric space group (Z' = 1) and the other in a centrosymmetric space group with two molecules in the asymmetric unit (Z' = 2). Topological analysis based on QTAIM clearly brings out the dominance of the chalcogen bond over the halogen bond along with an indication that halogen bonds are more directional compared to chalcogen bonds. The cohesive energies calculated with the absence of both strong and weak hydrogen bonds as well as stacking interaction are indicative of the stabilities associated with the polymorphic forms.

Exploring the simultaneous σ-hole/π-hole bonding characteristics of a Br...π interaction in an ebselen derivative via experimental and theoretical electron-density analysis

“…S5) show essential chemical features such as the anisotropic electron-density distribution around the Br atom. Furthermore, in accordance with previous reports of related experimental charge-density studies (Pavan et al, 2015), the presence of a charge-depleted region on the Br atom along the extension of the C-Br bond was clearly evident.…”

Chalcogen Bonding “2S–2N Squares” versus Competing Interactions: Exploring the Recognition Properties of Sulfur

“…In each crystal shown in Figure , there are at least two Br ⋅⋅⋅ Br or I ⋅⋅⋅ I contacts for each monomer that are at or below the respective van der Waals radii sum of 3.70 Å for (Br+Br) and 3.96 Å for (I+I). We note that the addition of polarizing nitro groups tightens the XB interactions even further, as observed in 9 g , which now includes near linear Br ⋅⋅⋅ Br/N contacts at 3.47 and 3.06 Å, respectively. A new O ⋅⋅⋅ S donor–acceptor contact at 3.21 Å also emerges, which is below the sum of the van der Waal radii of (O+S)=3.32 Å.…”

“…[110][111][112][113] In each crystal shown in Figure10, there are at least two Br···Br or I···Ic ontacts for each monomer that are at or below the respective van der Waals radii sum of 3.70 for (Br + Br) and 3.96 for (I + I). We note that the addition of polarizing nitro groups tightenst he XB interactions even further,a so bserved in 9g, [113] which now includes near linear Br···Br/N contacts at 3.47 and 3.06 ,r espectively.Anew O···Sd onor-acceptor contact at 3.21 also emerges,w hich is below the sum of the van derW aal radii of (O + S) = 3.32 . Fluorination:Distinct from the derivatives bearing higherhalogen substituents, highly aligneds quares are abundantf or most of the fluoro-benzothiadiazoles (5b, 7, 8, 9b-9e).…”

A Computational Study of Chalcogen‐containing H2X…YF and (CH3)2X…YF (X=O, S, Se; Y=F, Cl, H) and Pnicogen‐containing H3X′…YF and (CH3)3X′…YF (X′=N, P, As) Complexes

“…[31] An early study of non-covalent interactions involving chalcogen atoms was reported for systems containing F 2 O, F 2 S and F 2 Se. [34] A large-scale computational study exploring the main features of chalcogen bonding for a series of donors (involving S, Se and Te atoms) complexed with halide ions and neutral Lewis bases (containing O, N and C atoms) was recently reported. [34] A large-scale computational study exploring the main features of chalcogen bonding for a series of donors (involving S, Se and Te atoms) complexed with halide ions and neutral Lewis bases (containing O, N and C atoms) was recently reported.…”