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the synthetic, thermodynamic and/or structural properties of complex formation of a range of transition metal ions1 were investigated previously as potential metal-ion-selective reagents.2 Since the title compound has two Nand three Odonor atoms in the macrocyclic ring, it may be a potential metal-ion-selective reagent for transition, alkaline and alkaline earth metal ions. The title compound was prepared from the reduction of a diimine-crown compound3 (2.0 g, 5.7 mmol) with borax (1.2 g, 30.0 mmol) and sodium borohydride (1.2 g, 31.0 mmol) in dry methanol (300 ml). The mixture was refluxed for 4 h. Later, methanol was evaporated and the residue was extracted with diethylether. The organic layer was dried with magnesium sulfate, evaporated and crystallized from diethylether (mp 357 K). The results of an X-ray structure determination are given in Tables 1 – 3. The hydrogen atoms were located by a difference Fourier synthesis and a geometrical calculation, with the parameters of 16 hydrogen atoms (out of 56) also being refined. The crystal has two molecules (Fig. 2) in an asymmetric unit. The conformations of the two independent molecules in the asymmetric unit are not considerably different from each other. The ligand cavity plays an important role in the complexation and metal-ion selectivity. The intramolecular C19···O2 [5.658(5)], N1···O1 [5.591(6)], N1···O2 [4.829(6)], N2···O2 [4.059(6)], N2···O3 [4.737(5)Å] (molecule A) and C40···O5 [4.666(6)], N3···O5 [4.198(5)], N3···O6 [4.891(5)], N4···O4 [6.534(6)] N4···O5 [5.898(5)Å] (molecule B) distances may indicate the hole sizes of the macrocyclic rings. The relative macrocyclic inner-hole sizes, estimated as being twice the mean 801 ANALYTICAL SCIENCES JUNE 2001, VOL. 17 2001 © The Japan Society for Analytical Chemistry

Crystal Structure of 3,4,6,7,15,16,17,18,19,20,21-Undecahydro-2,5,6-trioxa-16,20-diazatricyclo[20.4.0.09,14]hexacosa-9,11,13,22,24,26(1)-hexaene