HOST-GUEST COMPLEXATION. 43. SYNTHESIS AND BINDING PROPERTIES OF A MACROCYCLE COMPOSED OF TWO PHENANTHROLINES AND TWO SULFONAMIDE UNITS

Article abstract of DOI:10.1016/S0040-4020(01)87669-9

Treatment of 2,9-bis(chloromethyl)-1,10-phenanthroline with toluenesulfonamide and K2CO3 in HCON(CH3)2 gave macrocycle 1 (21percent) composed of two phenanthroline units bonded to each other through two CH2N(Ts)CH2 bridges.The 18-membered inner ring system contains six nitrogens, each of which is separated by two carbons.A crystal structure of 1.2 H2O 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 ArSO2N groups are turned outward, and the hydrogens of their attached CH2 groups are oriented inward t oward the water dimer, which serves as a guest.Complexation was indicated by addition of a variety of salts to a solution of 1 in (CD3)2SO, which casued changes in the 1H NMR by as much as 1.5 ppm.Complexing ions include Li(+), Na(+), K(+), Rb(+), Cs(+), NH4(+), Ag(+), Cu(+), Tl(+), Zn(2+), Cd(2+), Hg(2+) and Pb(2+); noncomplexing ions are Mg(2+), Ca(2+), Sr(2+), Ba(2+), UO2(2+), and Ce(3+).A correlation between the chemical shifts of the CH3 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 NH4(+) picrates in (CD3)2SO provided the following estimates of the -ΔG deg values of binding of these salts by 1: 8.4, 8.5, 6.8, <3.5, and 8.85 kcal/mol, respectively.