Vol. 2, Issue 9, Part G (2016)

Abstract
The molecular and crystal structure of imperatorin, phellopterin and rutaretin have been determined by using crystallographic and computational techniques. The compound of imperatorin crystallizes in triclinic space group P1 ̅ with unit cell parameters a=11.1150(10)Å, b=11.8240(10)Å, c=11.9290(10)Å, α=64.90(1)°, β=83.53(1) °, γ=89.25(1) °. The compound of phellopterin crystallizes in triclinic space group P1with unit cell parameters a=8.431(3)Å, b=8.947(3)Å, c=11.125(4)Å, α=64.11(5)°, β=71.13(5) °, γ=78.04(5) °. The compound of rutaretin crystallizes in monoclinic space group C2 with unit cell parameters a=24.616(8)Å, b=8.186(3)Å, c=6.632(2)Å, β=103.99(2) °. The number of molecules per unit cell is 4 for imperatorin and rutaretin and 2 for phellopterin. The crystal structure of imperatorin has two asymmetric molecule whereas phellopterin and rutaretin have one asymmetric molecule. The final R-factor for (imperatorin) is 0.0431, (phellopterin) 0.0592 and (rutaretin) 0.0356. All the three molecules exhibit intra and inter C-H...O hydrogen bonding. A comparative crystallographic analysis of these three photoactive furanocoumarins is reported in this paper.