Organization of Lower Rim <i>O</i>-Alkylated <i>p</i>-Phosphonic Acid Calix[4]arenes

Lower rim O-methyl, -n-butyl, and n-octadecyl calix[4]arenes bearing p-phosphonic acid groups on the upper rim have been prepared in high yield, compounds 12−14. Where possible, the compounds have been characterized in the solid state using X-ray diffraction, or as the precursor phosphate esters or a cesium salt. The cone conformation ethyl phosphate ester for the octadecyl compound crystallizes in a bilayer 39.1 Å thick, which approaches the 40 Å of biological membranes. The 1,3-alternate cone conformation of the cesium salt of the O-methyl phosphonic acid has a metal ion coordinated to two methoxy groups, four O−P (two from neighboring calixarenes), and two η3-C3 moieties from two 1,3-disposed aromatic rings. MALDI-TOF spectra of compounds 12−14 show successive peaks corresponding to 15, 33, and 16 calixarene units, which is consistent with the intramolecular H-bonding capabilities of the diprotic phosphonic acid groups where the calixarenes are arranged into layers, including bilayers.以高产率合成得到上缘带有对膦酸基团的下缘O-甲基、正丁基及正十八烷基杯[4]芳烃（calix[4]arenes），即化合物12~14。在可行条件下，通过X射线衍射（X-ray diffraction）对固态样品进行表征，或以其前体磷酸酯或铯盐的形式完成表征。该十八烷基衍生物的锥式构象磷酸乙酯以39.1埃厚的双层结构结晶，其层厚接近生物膜的40埃。O-甲基膦酸铯盐的1,3-交替锥式构象中，金属离子与两个甲氧基、四个O-P键（其中两个来自相邻的杯[4]芳烃分子）以及来自两个1,3-位芳环的两个η³-C3基团配位结合。化合物12~14的基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）图谱显示出依次对应15、33和16个杯[4]芳烃单元的特征峰，这与双质子膦酸基团的分子内氢键能力相符，此时杯[4]芳烃分子可组装为包括双层结构在内的多层聚集体。