Tetraallyl Ethers of Thiacalix[4]arenes in the 1,3-Alternate Conformation

Abstract

The O-alkylation of thiacalix[4]arene and of two derivatives substituted in p-position by NO₂ and p-N=N–C₆H₄–NO₂ with allylbromide leads to tetraallyl ethers in the 1,3-alternate conformation (1–3) as proved by X-ray crystallography. Compound 1 crystallized in the trigonal space group P3₂21 with unit cell parameters a = 10.9608(4) Å, b = 10.9608(4) Å, c = 24.6730(12) Å; α = 90°, β = 90°, γ = 120° and Z = 3. Compound 2 crystallized in the orthorhombic space group Pbca with unit cell parameters a = 12.8608(4) Å, b = 17.5209(5) Å, c = 33.6527(9) Å; α = 90°, β = 90°, γ = 90° and Z = 8. Compound 3 crystallized in the monoclinic space group P2₁/n with unit cell parameters a = 18.7825(19) Å, b = 17.6662(13) Å, c = 19.7828(18) Å; α = 90°, β = 114.152(7)°, γ = 90° and Z = 4. Subtle differences in the molecular shape of the calix[4]arene core were found. The unsubstituted compound 1 forms three alternating layers with parallel tubes of different orientation, while for 3 all molecules are arranged in tubes parallel to the a-axis. Layers of molecules parallel to the a, b-plane are found for compound 2.

Graphical Abstract

The crystal structures of three thiacalix[4]arene tetraallyl ethers in the 1,3-alternate conformation, differing by their substituents in p-position (H, NO₂, N=N–C₆H₄–NO₂) are reported.