CROWN-ETHER ANALOGS AND THEIR COMPLEXES - SOLID-STATE AND SOLUTION STEREOCHEMISTRY OF DIBENZO-15-CROWN-4 ETHER AND ITS 2/2 COMPLEX WITH SODIUM-IODIDE AS STUDIED BY X-RAY CRYSTALLOGRAPHY AND NMR SPECTROSCOPIC METHODS

The structures of the title systems have been determined by X-ray crystallography. The sodium iodide complex has 2:2 stoichiometry and C-i symmetry. Each sodium cation coordinates to four oxygen atoms of one macrocyclic unit and one oxygen of the other 15-membered ring of the dimer. The 400 MHz H-1 NMR spectra have been analysed and assignments made on the basis of NOESY and COSY experiments. Solution C-13 NMR spectra have been assigned using HETCOR methods. Solid-phase C-13 NMR spectra are included and the results of sodium complexation on the solid-phase C-13 chemical shifts are discussed. [4-H-2(4)] Dibenzo-15-crown-4 has been synthesized and employed as an aid in spectral assignments.