Polyamide–polyamine hybrid macrobicycle L is explored with respect to its ability to bind α,ω-dicarboxylate anions. Potentiometric studies of protonated L with the series of dianions from succinate (suc^2–) through glutarate (glu^2–), α-ketoglutarate (kglu^2–), adipate (adi^2–), pimelate (pim^2–), suberate (sub^2–), to azelate (aze^2–) have shown adipate preference with association constant value of K = 4900 M^–1 in a H₂O/DMSO (50:50 v/v) binary solvent mixture. The binding constant increases from glu^2– to adi^2– and then continuously decreases with the length of the anion chain. Further, potentiometric studies suggest that hydrogen bonding between the guest anions and the amide/ammonium protons of the receptor also contributes to the stability of the associations along with electrostatic interactions. Negative-mode electrospray ionization of aqueous solutions of host–guest complexes shows clear evidence for the selective formation of 1:1 complexes. Single-crystal X-ray structures of complexes of the receptor with glutaric acid, α-ketoglutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid assist to understand the observed binding preferences. The solid-state structures reveal a size/shape complementarity between the host and the dicarboxylate anions, which is nicely reflected in the solution state binding studies.

中文翻译：

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聚酰胺-多胺甲酰胺作为二羧酸盐受体：在固态，溶液中和气相中的阴离子键结合研究

研究了聚酰胺-多胺杂化大脚踏车L的结合α，ω-二羧酸根阴离子的能力。从琥珀酸（suc ^2–）到谷氨酸（glu ^2–），α-酮戊二酸（kglu ^2–），己二酸（adi ^2–），庚二酸（pim ^2–），辛二酸（pikate ）系列阴离子的质子化L的电位测量研究子^2- ），壬二至（AZE ^2-）已显示具有缔合常数值己二酸偏好ķ = 4900中号^-1再在H ₂ O / DMSO（50:50 v / v）的二元溶剂混合物。结合常数从glu增加^2–到adi ^2–然后随着阴离子链的长度不断减小。此外，电位研究表明，客体阴离子与受体的酰胺/铵质子之间的氢键结合静电相互作用也有助于缔合的稳定性。主客体复合物水溶液的负模式电喷雾电离显示了选择性形成1：1复合物的明确证据。受体与戊二酸，α-酮戊二酸，己二酸，庚二酸，辛二酸和壬二酸的复合物的单晶X射线结构有助于理解观察到的结合偏好。固态结构揭示了主体与二羧酸根阴离子之间的大小/形状互补性，这在溶液状态结合研究中得到了很好的体现。