Temperature-dependent guest-driven single-crystal-to-single-crystal ligand exchange in a two-fold interpenetrated Cd(II) grid network.

A doubly interpenetrated square-grid coordination polymer {[Cd(ImBNN)(2)(CF(3)SO(3))(2)])guest}(n) (1) (guest = C(7)H(8) and ImBNN = 2,5-bis[4'-(imidazol-1-yl)phenyl]-3,4-diaza-2,4-hexadiene) that contains cavities able to accommodate toluene guest molecules has been assembled by the reaction of the Schiff base ligand ImBNN and Cd(CF(3)SO(3))(2). The framework 1 shows dynamism in either temperature-dependent expansion and shrinkage or cooperatively temperature-dependent guest-driven ligand exchange at the metal center. Studies of guest removal/uptake by heating in a vacuum, cooling in air, and then heating in toluene at reflux have revealed a series of single-crystal-to-single-crystal structural transformations: complex 1 lost toluene guests and captured water molecules to give guest-free 1 b via a proposed metastable phase 1 a, and 1 b could readsorb toluene guests to give 1', which represents a restored 1.

Guest inclusion and interpenetration tuning of Cd(II)/Mn(II) coordination grid networks assembled from a rigid linear diimidazole Schiff base ligand.

Cd(II)/Mn(II) coordination grid networks containing large meshes have been assembled from a long rigid ligand, 2,5-bis(4'-(imidazol-1-yl)benzyl)-3,4-diaza-2,4-hexadiene (ImBNN), and M(CF(3)SO(3))(2) (M = Cd and Mn) salts, and their interpenetration change upon guest inclusion has been investigated with a series of aromatic molecules. Without guest molecules, the grid networks are triply interpenetrated to form closely packed layer structures [M(ImBNN)(2)(CF(3)SO(3))(2)](n) (M = Cd (1) and Mn (2)), but when guest molecules are introduced, the triply interpenetrated frameworks are changed to doubly interpenetrated ones with the inclusion of various aromatic molecules, namely, {[M(ImBNN)(2)(CF(3)SO(3))(2)] superset guest}(n) (M = Cd, guest = o-xylene (3), naphthalene (4), phenanthrene (5), and pyrene (6); M = Mn, guest = benzene (7), p-xylene (8), naphthalene (9), phenanthrene (10), and pyrene (11)). These complexes have been characterized by means of single-crystal X-ray diffraction, X-ray powder diffraction, and IR spectra.