Crystal structures and Hirshfeld surface analyses of N,N-dimethylacetamide-1-(dimethyl-λ4-azanylidene)ethan-1-ol tribromide (1/1), N,N-dimethylacetamide-1-(dimethyl-k4-azanylidene)ethan-1-ol dibromidoiodate (1/1) and N,N-dimethylacetamide-1-(dimethyl-λ4-azanylidene)ethan-1-ol dichloridoiodate (1/1)

In the title compounds, N,N-dimethylacetamide-1-(dimethyl-lambda(4)-azanylidene)-ethan-1-ol tribromide (1/1), C4H9NO center dot C4H10NO+center dot Br-3(-) or [(C4H9NO)center dot(C4H10NO)](Br-3), (I), N,N-dimethylacetamide-1-(dimethyl-lambda(4)-azanylidene)ethan-1-ol dibromidoiodate (1/1), C4H9NO center dot C4H10NO+ center dot Br2I- or [(C4H9NO)center dot(C4H10NO)](Br2I), (II), and N,N-dimethylacetamide-1-(dimethyl-lambda(4)-azanylidene)ethan-1-ol dichloridoiodate (1/1), C4H9NO center dot C4H10NO+center dot Cl2I- or [(C4H9NO)center dot(C4H10NO)]center dot(Cl2I), (III), all the anions are almost linear in geometry and all the cations, except for the methyl H atoms, are essentially planar. In the crystal structure of (I), the cations are linked by pairs of C-H center dot center dot center dot O hydrogen bonds, forming inversion dimers with an R-2(2)(8) ring motif. These dimers also exhibit O-H center dot center dot center dot O hydrogen bonding. Dimerized cation pairs and anions are arranged in columns along the a axis. In the crystal of (II), the cations are linked by pairs of O-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, forming an R-4(4)(14) ring motif. These groups of cations and the anions form individual columns along the a axis and jointly reside in planes roughly parallel to (011). In the crystal of (III), cations and anions also form columns parallel to the a axis, resulting in layers parallel to the (020) plane. Furthermore, the crystal structures of (I), (II) and (III) are consolidated by strong halogen (Br and/or I and/or Cl)center dot center dot center dot H and weak van der Waals interactions. In addition to the structural evaluation, a Hirshfeld surface analysis was carried out.

Automated summary

This paper presents the crystal structures of three compounds and their interactions, revealing the molecular arrangement and bonding modes between them.