MOLECULAR-STRUCTURE OF NOVEL POLYMER-LIKE COMPLEXES OF ARMED-AZACROWNETHERS WITH ALKALI-METAL CATIONS

Armed-azacrown ethers nzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadeca ne 1, ylbenzyl)-1,4,7,10-tetraoxa-13-azacyclopentadecane 2 and -1,4,7- trioxa-10-azacyclododecane 3, and their alkali-metal complexes were pr epared. Single crystal structures have been determined for 1, 1 . KI . 3H(2)O, 1 . KSCN . H2O, 2 . NaSCN, 2 . KSCN, 2 . RbSCN and 2 . CsSCN, 3, 3 . LiSCN . H2O, 3 . LiBr . 3H(2)O and 3 . RbSCN. The:compounds 1 . KI . 3H(2)O and 1 . KSCN . H2O are normal 1:1 complexes, but 2 . NaS CN, 2 . KSCN, 2 . RbSCN and 2 . CsSCN are novel polymer-like (1:1)n co mplexes in which the phenolic OH group in the side arm of the crown et her co-ordinates to the cation incorporated in the crown moiety of ano ther molecule. In the complexes of 3, when Li+ is used as guest cation , the normal 1:1 complex is obtained, but Rb+ forms a polymer-like (2: 2)n complex. Fourier-transform IR spectra showed that the O-H stretchi ng band of the phenolic OH group in the polymer-like complexes shifted to lower frequency by ca. 210-290 cm(-1) compared with those of the c orresponding host compounds. Also, C-13 NMR titration experiments indi cated that the stoichiometry of the alkali-metal complexes with 2 and 3 in CD3CN-CD3OD (5:1) solution is 1:1, and thus they do not form poly mer-like complexes under these conditions.