S. J. Keipert, C. Knobler, D. Cram
1987
Citations
6
Influential Citations
151
Citations
Quality indicators
Journal
Tetrahedron
Abstract
Abstract Treatment of 2,9-bis(chloromethyl)-1,10-phenanthroline with toluenesulfonamide and K 2 CO 3 in HCON(CH 3 ) 2 gave macro-cycle 1 (21%) composed of two phenantroline units bonded to each other through two CH 2 N(Ts)CH 2 bridges. The 18-membered inner ring system contains six nitrogens, each of which is separated by two carbons. A crystal structure of 1.2H 2 O indicated the two faces of the phenanthrolines approach each other to place their four nitrogens nearly in a plane bridged by a water dimer held in position by bifurcated hydrogen bonds. The two ArSO 2 N groups are turned outward, and the hydrogens of their attached CH 2 groups are oriented inward toward the water dimer, which serves as a guest. Complexation was indicated by addition of a variety of salts to a solution of 1 in (CD 3 ) 2 SO, which casued changes in the 1 H NMR by as much as 1.5 ppm. Complexing ions include Li + . Na + , K + , Rb + , Cs + , NH 4 + , Ag + , Cu + , Tl + , Zn 2+ , Cd 2+ , Hg 2+ and Pb 2+ noncomplexing ions are Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , UO 2 2+ , and Ce 3+ . A correlation between the chemical shifts of the CH 3 and tolyl aryl protons of the host and the ionic radii of the guests is interpreted in terms of three different host conformations in the various complexes. Equilibrations of the guest cations between 1 and cryptaplexes of Na + , K + , Rb + , Cs + , and NH 4 + picrates in (CD 3 ) 2 SO provided the following estimates of the -ΔG° values of binding of these salts by 1: 8.4, 8.5, 6.8, -1 , respectively.