R. Sachleben, J. Burns, G. Brown
May 1, 1988
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Journal
Inorganic Chemistry
Abstract
A dibenzo-14-crown-4 ether with a pendant arm carrying a phosphinic acid moiety was synthesized and the crystal structure of its sodium salt determined by x-ray diffraction methods. The V-shaped macrocycle is almost identical with the unsubstituted version and has its four ether O atoms oriented to one side in a plane. The Na/sup +/ ion is bonded to these atoms and is 1.5 /angstrom/ above the plane; it is also bonded to the O atom of the oxymethyl side arm and to the O atoms of one water and one ethanol molecule. The phosphinate anion does not coordinate directly to the Na/sup +/ ion but is attached indirectly through an intermediate H/sub 2/O molecule. A hydrogen bonding network joins the complex molecules into dimers that interact with each other in the crystal only through van der Walls contacts. The acid and the salt were also characterized by ir and NMR spectroscopy, and the pK/sub a/ was determined to be 4.5 in 80% methanol-water. Crystallographic data for NaPC/sub 29/H/sub 42/O/sub 11/: monoclinic, a = 18.439 (2) /angstrom/, b = 8.680 (1) /angstrom/, c = 20.606 (1) /angstrom/, /beta/ = 102.95 (1)/degree/, space group P2/sub 1//n, Z = 4. 28 refs., 2more » figs., 5 tabs.« less