Investigation of hexakis[2-formylphenoxy]cyclotriphosphazene structure by single crystal X-ray diffraction and computer simulation

Crystallization of hexakis [2-formylphenoxy]cyclotriphosphazene was carried out from its melt and its solution. It was found that single crystals of this compound could be obtained via the slow crystallization from a chloroform-ethanol mixture. The melting point of such crystals was determined by the DSC method. These crystals have been for the first time investigated using the single crystal X-ray diffraction analysis. It was found that the phosphazene cycle in hexakis [2-formylphenoxy]cyclotriphosphazene is not planar in contrast to the starting hexachlorocyclotriphosphazene. The results acquired by X-ray diffraction were used in theoretical calculations of the characteristics of molecule. It was revealed that the spatial configuration of substituents in hexakis [2-formylphenoxy]cyclotriphosphazene is highly symmetrical towards the phosphazene cycle. There are pi-stacking interactions between some aromatic cycles. The molecular framework is formed mainly by the C center dot center dot center dot H, C center dot center dot center dot C and H center dot center dot center dot H intramolecular interactions. A deformation of the phosphazene cycle arises due to asymmetric intramolecular hydrogen bonds between the nitrogen atoms of phosphazene cycle and the hydrogen atoms of aromatic rings. Performed structural calculations revealed the diameter of a sphere circumscribing the phosphazene molecule, which was 1.5 nm. These results of structural investigations may be of interest for the molecular design, theoretical prediction of the properties of new compounds, synthesis of coordination compounds, and nanotechnology. (C) 2020 Elsevier B.V. All rights reserved.