Crystalline inclusion compounds of substituted 2,2′-bis(9-hydroxy-fluoren-9-yl)biphenyls: synthesis, X-ray crystal structures and thermal analysis study of inclusion compounds with butyronitrile, cyclohexanone, cyclopentanol and dimethylformamide
Abstract
The syntheses of 2,2′-bis(2,7-di-tert-butyl-9-hydroxyfluoren-9-yl)biphenyl (2), 2,2′-bis(2,7-dichloro-9-hydroxyfluoren-9-yl)biphenyl (3) and 2,2′-bis(2,7-dibromo-9-hydroxyfluoren-9-yl)biphenyl (4) are reported. Inclusion compounds were prepared with these hosts: 5=2·butyronitrile (1:1), 6=3·cyclohexanone (1: 2), 7=3·cyclopentanol (1: 2), 8=4·dimethylformamide (1:2). Crystal data: 5, monoclinic, C2/c with a= 17.174(2), b= 17.985(3), c= 17.333(3)Å, β= 113.73(1 )°, Z= 4, Dc= 1.10 g cm–3; 6, monoclinic, P21/n with a= 15.048(3), b= 16.106(4), c= 19.10(1)Å, β= 112.97(4)°, Z= 4, Dc= 1.32 g cm–3; 7, monoclinic, P21/c with a= 14.576(2), b= 15.783(4), c= 19.561 (4)Å, β= 111.72(1)°, Z= 4, Dc= 1.31 g cm–3; 8, triclinic, P with a= 11.52(1), b= 11.825(1), c= 17.836(1)Å, α= 79.19(5), β= 71.15(7), γ= 60.85(7)°, Z= 4, Dc= 1.62 g cm–3. Final R values for the four structures were 0.071, 0.062, 0.077 and 0.096 for 2489, 3270, 3432 and 3802 reflections, respectively. Host ⋯ guest hydrogen bonds are observed in all four structures and there is an intramolecular hydrogen bond in the hosts 5–7. In addition, in compounds 6–8 there are a number of O ⋯ Cl, Cl ⋯ Cl, N ⋯ Br and Br ⋯ Br interactions. Thermal analysis was used to study the binding of the guest molecules and indicated that the guests in 5–7 were more strongly held than that in 8.