Erythronium Bonds: Noncovalent Interactions Involving Group 5 Elements as Electron Density Acceptors

: Analyses of the Cambridge Structural Database and theoretical calculations (PBE0-D3/def2-TZVP level, atoms-in-molecules, natural bond orbital studies) prove the formation of net attractive noncovalent interactions between group 5 elements and electron-rich atoms (neutral or anionic). These bondings are markedly different from coordination bonds formed by the same elements and possess the distinctive features of σ-hole interactions. The term erythroniumbond is proposed to denote these bonds. X-ray structures of vanadate-dependent bromoperoxidases show these interactions are present also in biological systems.