Synthesis, characterization and crystal structure of two triethylene glycol derivatives

Abstract

In this study, two compounds of triethylene glycol bistosylate (C₂₀H₂₆O₈S₂, I) and 1,8-bis(4-nitrophenoxy)-3,6-dioxaoctane (C₁₈H₂₀N₂O₈, II) were synthesized. Their structures were characterized by ¹H NMR, ¹³C NMR, FT-IR, melting-point and elemental analysis, as well as X-ray single-crystal diffraction. The analyses of X-ray single crystal diffraction showed that the monomer of compound I was in sigmoid conformation due to the intramolecular C-H···π interaction, furthermore, a 3D network structure was constructed by five C-H···O hydrogen bonds. Unlike the compound I, the compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure. Host-guest chemistry of compounds II and β-cyclodextrin was also investigated by ¹H NMR, FT-IR and UV-Vis spectra. The binding ratio of the compound II and β-cyclodextrin was 1:2 and the association constant Ka was 5.31 × 10⁴ L²·mol⁻² obtained by UV-Vis spectra.

GRAPHICAL ABSTRACT

The X-ray single-crystal structural characterization suggests that the compound I was in sigmoid conformation due to the intramolecular C-H···π interaction, furthermore, a 3D network structure was constructed by five C-H···O hydrogen bonds formed between the monomers through SO₃ groups and the hydrogen atoms on the surrounding three monomers glycol. The compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure.

Highlights

• The two triethylene glycol derivatives (compound I, compound II) have been synthesized and characterized by ¹H NMR, IR, melting point, elemental analysis and X-ray single crystal diffraction.

• The single crystals of compound I and compound II were cultured, and their intermolecular solid-state structures and weak interactions were obtained by X-ray single crystal diffraction.

• The compound I was in special sigmoid conformation due to the intramolecular C-H···π interaction and a 3D network structure was constructed by five intermolecular C-H···O hydrogen bonds.

• The compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure.

• The H-bonding interactions in the compound I and compound II were studied.

• The host-guest chemistry between compound II and β-cyclodextrin was investigated including the apparent stoichiometry ratio and the association constant (Ka) between them.

Keywords:

• Open chain crown ether
• triethylene glycol
• crystal structure
• hydrogen bond

Additional information

Funding

The work was supported by the National Natural Science Foundation of China (No.21301139, 21073139, 21103135), China Scholarship Council (No. 201808615050) and Natural Science Basic Research Plan in Shaanxi Province of China (No. 2015JQ2043).