Co-crystal sustained by π-type halogen-bonding inter-actions between 1,4-di-iodo-perchloro-benzene and naphthalene

Abstract

The formation and crystal structure of a co-crystal based upon 1,4-di-iodo-perchloro-benzene (C₆I₂Cl₄) as the halogen-bond donor along with naphthalene (nap) as the acceptor is reported. The co-crystal [systematic name: 1,2,4,5-tetra-chloro-3,6-di-iodo-benzene-naphthalene, (C₆I₂Cl₄)·(nap)] generates a chevron-like structure that is held together primarily by π-type halogen bonds (i.e. C-I⋯π contacts) between the components. In addition, C₆I₂Cl₄ also inter-acts with the acceptor via C-Cl⋯π contacts that help stabilize the co-crystal. Within the solid, both aromatic components are found to engage in offset and homogeneous face-to-face π-π stacking inter-actions. Lastly, the halogen-bond donor C₆I₂Cl₄ is found to engage with neighboring donors by both Type I chlorine-chlorine and Type II iodine-chlorine contacts, which generates an extended structure.

Keywords: Type I chlorine-chlorine contacts; Type II iodine-chlorine contacts; co-crystal; halogen bonding.