Crystal and molecular structure of [5]helicene: crystal packing modes
Abstract
The crystal and molecular structure of two crystal habits of [5]helicene, forms A and B, have been determined and their respective crystal packing modes are compared, together with those of other members of the helicene series. Form A crystallizes from n-pentane in the space group P21/c with a= 5.8150(7), b= 14.178(1), c= 17.498(1)Å, β= 94.41(1)°, Z= 4, while form B from ethanol solution belongs to the space group A2/a with a= 26.013(2), b= 8.898(1), c=19.494(2)Å, β= 103.94(1)°, Z=12.