K. R. Koch, M. Niven, C. Sacht
1992
Citations
0
Influential Citations
5
Citations
Journal
Journal of Coordination Chemistry
Abstract
Abstract The crystal structures of 1,8-bis(quinolyloxy)-3,6-dioxaoctane complexes of potassium tosylate (I) and potassium isothiocyanate (II) have been determined and compared. Both complexes form monoclinic crystals belonging to the P21/c space group with a = 8.152(2), b = 23.097(6), c=16.076(5) A, β=102.14(2)[ddot], Z=4 for (I), and a = 11.172(2), b = 22.177(2), c = 9.960(2) A, β = 93.51(2)[ddot], Z=4 for (II). In both cases the hexadentate podand wraps around the potassium ion in a helical fashion, while the isothiocyanate and tosylate anions strongly coordinate to the metal ion (K+ …O(3) = 2.620(2)A (I); K+ …N(3) = 2.737(7): (II)), the potassium ion having a coordination number of seven. As a consequence of strong ion-pair formation between the potassium ion and the isothiocyanate and tosylate anions, the podand adopts a subtly different conformation around the metal ion in the two complexes, presumably accommodating the different steric demands of the two anions. The marked differences in the 1H NMR ...