A water-soluble calix[6]arene-based azacryptand was synthesized. The corresponding tren [tris(2-aminoethyl)amine] cap grafted at the small rim coordinates strongly a copper(II) ion over a wide range of pH. The host–guest properties of the complex were explored by EPR spectroscopy. Due to second coordination sphere effects and the hydrophobic effect ascribed to the calixarene cavity, this funnel complex selectively binds neutral molecules (alcohols, nitriles, amines) versus anions in water near physiological pH. Among the coordinating guests, hydrophobic primary amines are preferentially recognized thanks to the combined effect of the better metal–ligand interaction and hydrogen bonding to the oxygen atoms present at the small rim. Hence, this Cu(II) calix[6]arene-based funnel complex behaves as a sensitive and selective EPR probe for primary amines, including biologically important molecules such as tyramine and tryptamine, in water, over a large pH window.

中文翻译：

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用杯[6]基于氮杂杂铜的漏斗络合物对水中的伯胺进行选择性EPR检测

合成了一种水溶性杯[6]芳烃基氮杂聚糖。接枝在小边缘上的相应的[三（2-氨基乙基）胺]帽在很宽的pH范围内都能强烈地协调铜（II）离子。通过EPR光谱研究了该复合物的宿主-客体特性。由于第二个配位球效应和杯形芳烃腔的疏水作用，该漏斗络合物选择性地结合生理pH值附近的水中的中性分子（醇，腈，胺）和阴离子。在配位客体中，由于更好的金属-配体相互作用和氢键合到小边缘处的氧原子上的结合作用，疏水性伯胺被优先识别。因此，