Discrete M2L2 metallacycle and M2L4 cage frameworks and anion competitive reactions of Cu2L4 type receptor

Complexes [Cu2(bitmb)2Cl4] (1), image · CH3OH · 6 H2O (2) and image(BF4)3 · 2 CH3OH · 4 H2O (3) are obtained by reaction of bitmb and Cu2+ salts with different anions (image) at different M:L ratio (1:1, 1:2 or 1:2). The results reveal that complex 1 is a neutral Cu2L2 rectangle and complexes 2 and 3 are M2L4 cage-like frameworks with an anion as guest. The anion competitive reaction of the Cu2L4 type receptor with tetrahedral, triangular and spherical anions (image) is reported. The anion competitive experiments demonstrate that the anion selective order is image, and image is the biggest and most preferable one, so far.