Inclusion Properties and Crystal Structure of Clathrates Constructed Based on “π-sandwich”

Abstract

Inclusion behavior of structurally similar host compounds, 1,4-bis[1-(9-anthryl)-3-propen-1-on-3-yl]benzene (1) and 1,4-bis[3-(9-anthryl)-3-propen-1-on-1-yl]benzene (2), has been studied. Both hosts preferred cyclic, non-branched small molecules as a guest component, to yield 1:2 clathrates specifically. X-ray powder diffraction studies revealed that those 1:2 clathrates of 1 and 2 were respectively isostructural. X-ray analyses of (1)(THF)₂ (P 1, a = 10.910(2), b = 19.656(5), c = 9.172(4) Å, α = 95.58(3), β = 93.67(2), γ = 103.30(2)°, D _calc = 1.195 g cm⁻³, Z = 2, and R = 0.067 for 8644 observed reflections) and (2)(1,4-dioxane)₂, (P2₁/n, a = 5.661(1), b = 17.971(3), c = 18.619(3) Å, β = 91.37(2)°, D _calc = 1.254 g cm⁻³, Z = 2, and R = 0.097 for 4353 observed reflections) illuminated that their guest preference should be ascribed to the commonly observed π-sandwich” structure, in which guest molecules are enclathrated between two anthracene planes of the host molecules.

Key Words:

• X-ray structure
• Clathrate
• Crystal engineering
• π-sandwich