Pnictogen bonding in pyrazine•PnX5 (Pn = P, As, Sb and X = F, Cl, Br) complexes

This paper presents a study of pnictogen bonding in a series of pyrazinea center dot PnX(5) (Pn = P, As, Sb and X = F, Cl, Br) complexes. The whole series was studied computationally. Moreover, the pyrazine complexes with PCl5 and SbCl5 were prepared and characterized experimentally. It was found that the Pn-N distances are only slightly elongated when compared to the sum of covalent radii. The conformation of PnX(5) changed considerably upon the complex formation, which resulted in a significant change of the dipole moment of the PnX(5) fragment and a considerably more positive sigma-hole on the pnictogen atom. Finally, interaction energies were decomposed in order to provide a deeper insight into the nature of the studied pnictogen-bonded complexes.