SELF-ASSEMBLY OF MOLECULAR BRICK WALL AND MOLECULAR HONEYCOMB FROM NICKEL(II) MACROCYCLE AND 1,3,5-BENZENETRICARBOXYLATE - GUEST-DEPENDENT HOST STRUCTURES

Novel multidimensional supramolecular networks with brick wall and hon eycomb structures, [Ni(C12H30N6O2)](3)[C6H3(COO)(3)](2). 18H(2)O (1) a nd [Ni(C12H30N6O2)](3)[C6H3(COO)(3)](2). 14H(2)O . 2C(5)H(5)N (2), res pectively, have been constructed by the self-assembly of S = 0 Ni(II) macrocyclic complex containing hydroxyl pendent chains and I,3,5-benze netricarboxylate (BTC3-). The host structures assembled are greatly af fected even by the partial change of the guests. X-ray crystal structu res indicate that each Ni(II) macrocycle binds two BTC3- in the trans position and each BTC3- coordinates three NI(II) macrocyclic units via C-1 symmetry in 1 and C-3 symmetry in 2. The simplest cyclic motif of the two-dimensional (2-D) networks in 1 and 2 is a large ring consist ing of six Ni(TI) macrocyclic complexes and six BTC3- anions. The ring s are extended to form a 2-D layer. The layers are stacked in parallel , separated by 8.850 Angstrom in 1 and 8.973 Angstrom in 2. They are i nterconnected by the hydrogen-bonding interactions between the hydroxy l pendants of the macrocycle in a layer and the secondary amines of th e macrocycle located in the neighboring layers, which gives rise to th e three-dimensional structures. The effective cavity size of 1 is ca. 6.7 x 13 Angstrom and that of 2 ca. 11.4 x 11.4 Angstrom. The cavities are filled with guest molecules. In 2, the pyridine guest experiences pi-pi interaction with the benzene ring of BTC3-. Variable-temperatur e (2-300 K) magnetic susceptibility measurements indicate chat both 1 and 2 exhibit weak anti-ferromagnetic interactions between the S = 1 N i(II) paramagnetic centers.