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首页> 外文期刊>Chemistry: A European journal >Cooperative Binding of Divalent Diamides by N-Alkyl Ammonium Resorcinarene Chlorides
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Cooperative Binding of Divalent Diamides by N-Alkyl Ammonium Resorcinarene Chlorides

机译：N-烷基铵间苯二甲酰氯对二价二酰胺的协同结合

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摘要

N-Alkyl ammonium resorcinarene chlorides, stabilized by an intricate array of hydrogen bonds leading to a cavitand-like structure, bind amides. The molecular recognition occurs through intermolecular hydrogen bonds between the carbonyl oxygen and the amide hydrogen of the guests and the cation-anion circular hydrogen-bonded seam of the hosts, as well as through CH interactions. The N-alkyl ammonium resorcinarene chlorides cooperatively bind a series of di-acetamides of varying spacer lengths ranging from three to seven carbons. Titration data fit either a 1:1 or 2:1 binding isotherm depending on the spacer lengths. Considering all the guests possess similar binding motifs, the first binding constants were similar (K-1:10(2)M(-1)) for each host. The second binding constant was found to depend on the upper rim substituent of the host and the spacer length of the guests, with the optimum binding observed with the six-carbon spacer (K-2:10(3)M(-2)). Short spacer lengths increase steric hindrance, whereas longer spacer lengths increase flexibility thus reducing cooperativity. The host with the rigid cyclohexyl upper rim showed stronger binding than the host with flexible benzyl arms. The cooperative binding of these divalent guests was studied in solution through (HNMR)-H-1 titration studies and supplemented by diffusion-ordered spectroscopy (DOSY), X-ray crystallography, and mass spectrometry.
机译：N-烷基铵间苯二甲酰氯被酰胺键结合，并通过复杂的氢键阵列（形成空洞状结构）而稳定。分子识别是通过客体的羰基氧和酰胺氢之间的分子间氢键与主体的阳离子-阴离子圆氢键合接缝以及通过CH相互作用而发生的。 N-烷基间苯二甲酰氯氯化物可结合结合一系列间隔长度为3至7个碳的二乙酰胺。根据间隔物的长度，滴定数据适合1：1或2：1的结合等温线。考虑到所有客人都具有相似的结合基序，对于每个宿主，第一结合常数是相似的（K-1：10（2）M（-1））。发现第二结合常数取决于主体的上边缘取代基和宾客的间隔物长度，六碳间隔物（K-2：10（3）M（-2））观察到最佳结合。较短的间隔物长度会增加空间位阻，而较长的间隔物长度会增加柔韧性，从而降低协作性。具有刚性环己基上边缘的主体显示出比具有柔性苄基臂的主体更强的结合力。通过（HNMR）-H-1滴定研究在溶液中研究了这些二价客体的协同结合，并辅以扩散有序光谱法（DOSY），X射线晶体学和质谱。

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