Three-Dimensional Supramolecular Architectures with CoII Ions Assembled from Hydrogen Bonding and π•••π Stacking Interactions: Crystal Structures and Antiferromagnetic Properties

Five Co-II complexes based on H3L1 and H3L2, namely, [Co-3(L-1)(2)(4,4'-bipy)(H2O)(3)](n) (1), [Co-3(L-1)(2)(4,4'-bipy)(3)(H2O)(4)](n) (2), {[Co-2(Li)(4,4'-bibp)(mu(3)-OH)(H2O)]center dot H2O}(n) (3), {[CO3(L-2)(2)(dib)(3)]center dot 2H(2)O}(n) (4), and [CO3(L-2)(2)(4,4'-bibp)(3)](n) (5) [(H3L1 = 4-[(3-carboxynaphthalen-2-yl)oxy]phthalic acid, H3L2 = 3-[(3-carboxynaphthalen-2-yl)oxy]phthalic acid, 4,4'-bipy = 4,4'-bipyridine, cub = 1,4-di(1H-imidazol-1-yl) benzene, and 4,4'-bibp = 4,4'-bis(imidazol)biphenyl] have been synthesized by solvothermal reactions. Complex 1 displays a (4,4,6) connected topology with a Schlafli symbol of (4.10(4).12)(4(11).6(4))(4(8).6)(2,) and the two-dimensional (2D) structure was assembled to form a three-dimensional (3D) framework by C-H center dot center dot center dot pi interactions of internaphthalene rings, showing the dominant antiferromagnetic exchanges in a triangular {Co3} cluster. Complex 2 presents a 2D (3,4,4)-connected network with a Schlafli symbol of (5.6(2))(2)(5(2).6(3).7)(2)(5(4).8(2)) and weakly antiferromagnetic behavior. Complex 3 features a novel (4,4,8)-connected topology with a Schlafli symbol of (3(2).4.5(2).6)(2)(3(2).4(2).5(2))(2)(3(4).4(6).5(8).6(7).7(2).8). In addition, complex 3 based on a parallelogram-shaped [Co-4(mu(3)-OH)(2)](6) secondary building unit provides antiferromagnetic interactions mediated by mu(3)-OH and syn-syn-COO- groups. The driving forces in 3D supramolecular frameworks are C-H center dot center dot center dot O, C-H center dot center dot center dot pi, and pi center dot center dot center dot pi stacking interactions for 2-3. Complexes 4-5 have an identical (4,4,5)-connected 2D network with a Schlafli symbol of (4.6(4).8)(4(2).6(7).8)(2)(4(4).6(2))(2). Additionally, the C-H center dot center dot center dot O hydrogen bonds between naphthalene rings and uncoordinated carboxy oxygen atoms extend 2D networks into 3D supramolecular frameworks. Magnetic investigations reveal that 4 and 5 exhibit antiferromagnetic interactions in the linear {Co3} unit.