Two-dimensional arrangements of bis(haloethynyl)benzenes combining halogen and hydrogen interactions

Abstract

The electronic distribution of some haloethynylbenzene derivatives may favor the formation of two-dimensional organizations by combining halogen and hydrogen bonds. In order to highlight this strategy, we have prepared seven cocrystals and analyzed their structures. 1,4-Bis(iodoethynyl)benzene, 1,4-bis(bromoethynyl)benzene, and 1,3-bis(iodoethynyl)benzene were used as halogen bond donors and 1,2-bis(4-pyridyl)ethylene, pyridazine, propanone, hexamethylenetetramine, and 2,8-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine (Tröger’s base) were employed as halogen bond acceptors. The crystal structures of seven halogen-bonded complexes show C–X···Y (X = I, Br; Y = N, O) distances shorter than the sum of the van der Waals radii, and six of them contain the edge-to-edge C–H···X (X = I, Br) supramolecular hydrogen bond synthon. The stabilization energies with basis set superposition error correction of hydrogen bond synthons have been determined by DFT calculations, and they are in the range 2.9 to 5.7 kcalmol–1. To gain a deeper understanding of these interactions, noncovalent interaction methodology was also applied.