Complexation with diol host compounds. Part 7. Structures and thermal analysis of 1,1,2,2-tetraphenylethane-1,2-diol with lutidine guests

Abstract

Structures of the inclusion compounds of 1,1,2,2-tetraphenylethane-1,2-diol with 2,6-lutidine (1), 3,5-lutidine (2) and 3,4-lutidine (3) have been determined. Crystal data: (1) C₂₆H₂₂O₂·C₇H₉N, M_r= 473.62, triclinic, P, a= 9.414(7), b= 11.191(4), c= 13.328(18)Å, α= 82.81 (7), β= 70.78(12), γ= 86.44(4)°, V= 1315.2 ų, Z= 2, D_m= 1.17, D_c= 1.20 g cm^–3, λ(Mo-K_α)= 0.710 69 Å, µ= 0.40 cm^–1, F(000)= 504. (2) C₂₆H₂₂O₂·(C₇H₉N)₂, M_r= 580.77, triclinic, P, a= 12.099(4), b= 17.869(5), c= 17.873(10)Å, α= 64.65(3), β= 87.32(4), γ= 75.25(2)°, V= 3368.4 ų, Z= 4, D_m= 1.12, D_c= 1.15 g cm^–3, λ(Mo-K_α)= 0.71069 Å, µ= 0.64 cm^–1, F(000)= 1240. (3) C₂₆H₂₂O₂·(C₇H₉N)₂, M_r= 580.77, triclinic, P, a= 9.163(4), b= 11.740(4), c= 17.721 (7)Å, α= 69.50(3), β= 74.22(4), γ= 73.09(4)°, V= 1677.2 ų, Z= 2, D_m= 1.14, D_c= 1.15 g cm^–3, λ(Mo-K_α)= 0.710 69 Å, µ= 0.38 cm^–1, F(000)= 620. The final R values at 293 K were (1) 0.043, (2) 0.070 and (3) 0.067 for 3382, 8561 and 4828 unique reflections. Strong host–guest hydrogen bonding is observed in all structures, O ⋯ N distances are between 2.664 and 2.889 Å. Thermal analysis revealed the strength of binding of the guest molecules and a competition experiment showed that 3,5-lutidine is preferentially included over 2,6-lutidine.