The structures of cyclohexan[b]indole N-β-propionic acid (1) and cyclooctan[b]indole N-β-propionic acid (2) have been determined by X-ray methods. The conformational populations of their N-β-propionic chains have been determined in solution by 1H nmr analyses. Crystals of 1 are triclinic, space group [Formula: see text] with a = 12.3562(4), b = 11.0727(3), c = 10.2050(4) Å, α = 108.519(3), β = 83.941(3), γ = 104.826(3)°, and Z = 4. Crystals of 2 are monoclinic, space group P21/c, with a = 5.636(1), b = 18.937(3), c = 13.976(4) Å, β = 98.84(3)°, and Z = 4. In both structures, the molecules are linked forming dimers through centrosymmetric H bonds. In solution the trans conformation of the chain is the preferred one in both compounds and increases with dilution until a constant value is reached.
环己[b]
吲哚N-β-
丙酸(1)和环辛[b]
吲哚N-β-
丙酸(2)的结构已通过X射线方法确定。通过1H NMR分析,已确定它们的N-β-
丙酸链的构象种群在溶液中。1的晶体属于三斜晶系,空间群[公式:见文本],a=12.3562(4) Å,b=11.0727(3) Å,c=10.2050(4) Å,α=108.519(3)°,β=83.941(3)°,γ=104.826(3)°,Z=4。2的晶体属于单斜晶系,空间群P21/c,a=5.636(1) Å,b=18.937(3) Å,c=13.976(4) Å,β=98.84(3)°,Z=4。在两种结构中,分子通过中心对称的氢键形成二聚体。在溶液中,两种化合物的链的反式构象是首选的,并随稀释而增加,直到达到常数值。