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

Complexes [Cu-2(bitmb)(2)Cl-4] (1), [(CH3OH)(NO3) subset of Cu-2(bitmb)(4)](NO3)(3) center dot CH3OH center dot 6 H2O (2) and [BF4 subset of Cu-2(bitmb)(4)](BF4)(3) center dot 2CH(3)OH center dot 4H(2)O (3) are obtained by reaction of bitmb and Cu2+ salts with different anions (BF4-, NO3- or Cl-) 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 (ClO4-, BF4-, NO3- and Cl-) is reported. The anion competitive experiments demonstrate that the anion selective order is ClO4- > BF4- > NO3- > Cl-, and ClO4- is the biggest and most preferable one, so far. (C) 2009 Elsevier B.V. All rights reserved.