The chalcogen bond is a nonclassical σ-hole-based noncovalent interaction with emerging applications in medicinal chemistry and material science. It is found in organic compounds, including 2D aromatics, but has so far never been observed in 3D aromatic inorganic boron hydrides. Thiaboranes, harboring a sulfur heteroatom in the icosahedral cage, are candidates for the formation of chalcogen bonds. The phenyl-substituted thiaborane, synthesized and crystalized in this study, forms sulfur⋅⋅⋅π type chalcogen bonds. Quantum chemical analysis revealed that these interactions are considerably stronger than both in their organic counterparts and in the known halogen bond. The reason is the existence of a highly positive σ-hole on the positively charged sulfur atom. This discovery expands the possibilities of applying substituted boron clusters in crystal engineering and drug design.

Current virtual screening tools are fast, but reliable scoring is elusive. Here, we present the 'SQM/COSMO filter', a novel scoring function featuring a quantitative semiempirical quantum mechanical (SQM) description of all types of noncovalent interactions coupled with implicit COSMO solvation. We show unequivocally that it outperforms eight widely used scoring functions. The accuracy and chemical generality of the SQM/COSMO filter make it a perfect tool for late stages of virtual screening.

This Minireview discusses the latest developments in modern quantum mechanics (QM)‐based computer‐aided drug design, especially using semiempirical QM (SQM) methods. It first tackles biochemical and biophysical quantities and the approaches to their measurements. Protein–ligand affinities are determined mostly by noncovalent interactions. The text thus illustrates how these can be accurately treated with SQM methods. Next, a construction of a modern SQM‐based scoring function is presented and its applications listed. In summary, SQM‐based scoring is a promising modern efficient strategy to be exploited in computer‐aided drug design.

We have recently introduced the "SQM/COSMO" scoring function which combines a semiempirical quantum mechanical description of noncovalent interactions at the PM6-D3H4X level and the COSMO implicit model of solvation. This approach outperformed standard scoring functions but faced challenges with a metalloprotein featuring a Zn···S interaction. Here, we invoke SCC-DFTB3-D3H4, a higher-level SQM method, and observe improved behavior for the metalloprotein and high-quality results for the other systems. This method holds promise for diverse protein-ligand complexes including metalloproteins.