Molecular structures and hydrogen-bond networks in crystals of synthetic 1- d-galactosamide bolaamphiphiles

Abstract

The crystal structures of synthetic 1-galactosamide bolaamphiphiles, N,N′-bis(β- d-galactopyranosyl)decane-1,10-dicarboxamide ( 1) and N,N′-bis(β- d-galactopyranosyl)dodecane-1,12-dicarboxamide ( 2), were determined by single-crystal X-ray analysis. The space groups are P2 1, Z=2 with cell dimensions: a=13.624(2), b=4.832(3), c=21.178(3) Å, β=98.57(1)° for 1; a=13.521(2), b=4.838(1), c=23.706(2) Å, β=104.945(10)° for 2. The galactopyranosyl rings of 1 and 2 are in a 4 C 1 chair conformation. The bolaamphiphile molecules are arranged in a layered structure for 1 and 2, with the alkylene chains packed parallel all over the layers. The hydroxyl groups of the galactopyranosyl rings in 1 and 2 form identical three-dimensional hydrogen-bond networks. The connecting decamethylene spacer of 1 has a kink conformation, while the dodecamethylene chain of 2 an all-trans zigzag conformation.