Can two trivalent N atoms engage in a direct N⋯N noncovalent interaction?

► Two N atoms attracted to one another if halogen substituent added to one N. ► Interaction energy of XN⋯N equal to 3.3-4.3 kcal/mol, comparable to OH⋯O H-bond in water dimer. ► Configurations containing XNH⋯N H-bond are more strongly bound; halogen bonds are weaker.