测量氡和氙与笼形分子主体的结合。
Measurement of radon and xenon binding to a cryptophane molecular host.
机构信息
Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
出版信息
Proc Natl Acad Sci U S A. 2011 Jul 5;108(27):10969-73. doi: 10.1073/pnas.1105227108. Epub 2011 Jun 20.
Xenon and radon have many similar properties, a difference being that all 35 isotopes of radon ((195)Rn-(229)Rn) are radioactive. Radon is a pervasive indoor air pollutant believed to cause significant incidence of lung cancer in many geographic regions, yet radon affinity for a discrete molecular species has never been determined. By comparison, the chemistry of xenon has been widely studied and applied in science and technology. Here, both noble gases were found to bind with exceptional affinity to tris-(triazole ethylamine) cryptophane, a previously unsynthesized water-soluble organic host molecule. The cryptophane-xenon association constant, K(a)=42,000 ± 2,000 M(-1) at 293 K, was determined by isothermal titration calorimetry. This value represents the highest measured xenon affinity for a host molecule. The partitioning of radon between air and aqueous cryptophane solutions of varying concentration was determined radiometrically to give the cryptophane-radon association constant K(a)=49,000 ± 12,000 M(-1) at 293 K.
氙气和氡气有许多相似的性质，不同之处在于氡气的所有 35 种同位素((195)Rn-(229)Rn)都是放射性的。氡气是一种普遍存在的室内空气污染物，据信在许多地理区域都会导致大量肺癌病例，但氡气与特定分子种类的亲和力从未被确定过。相比之下，氙气的化学性质已经得到了广泛的研究和应用。在这里，两种惰性气体都被发现与三-(三唑乙基胺)cryptophane 具有特殊的亲和力，这是一种以前未合成的水溶性有机主体分子。cryptophane-xenon 缔合常数，K(a)=42,000 ± 2,000 M(-1)在 293 K 时，通过等温滴定量热法确定。这个值代表了迄今测量到的对主体分子的最高氙气亲和力。通过放射性测定，确定了空气和不同浓度的水溶液之间的氡气分配，给出了 293 K 时的 cryptophane-radon 缔合常数 K(a)=49,000 ± 12,000 M(-1)。
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