Construction and modulation of structural diversity in acylamide-MOFs

A new N-donor ligand, N-1, N-4-di(pyridin-4-yl) naphthalene-1,4-dicarboxamide (L), has been designed and applied to generate seven new acylamide-MOFs, namely Cd(L)(tp) (1), Cd(L)(tp)(H2O)center dot(H2O)(3)center dot(CH3CH2OH)(3) (2), Zn(L)(nip) (3), [Zn(nip)(2)][H2L] (4), Zn(HL)(btc)center dot(H2O)(0.5) (5), Zn(L)(nap) (6), and Zn(L)(ip)center dot(H2O)(2)center dot(CH3CH2OH) (7) (H(2)tp = terephthalic acid, H(2)nip = 5-nitroisophthalic acid, H(2)nap = naphthalene-1,4-dicarboxylic acid, H(3)btc = benzene-1,3,5-tricarboxylic acid, H(2)ip = isophthalic acid). 1 presents a rare 4-connected sra framework with 8-fold interpenetration in a [4 + 4] manner. Similar reaction conditions, except for the reaction temperature and solvent, employed for 1 produced compound 2, which shows a 2D net with two-fold interpenetration in a parallel fashion. Compound 3 and compound 4 were also synthesized with the same materials but using different solvents and reaction temperatures; 3 shows a 2D two-fold interpenetrating net in a parallel fashion and 4 is a 1D chain but presents a 3D supramolecular net. In 5, the 2D layer is constructed by the Zn ions and btc(3-) ligands, and the singly protonated L ligand acts as a decoration while playing a puncturing role. 6 is a 3D pillared layered framework with alpha-Po topology and three-fold interpenetration, where Zn ions combine with the nap(2-) ligands to form a 2D layer and the L ligands act as the pillars. 7 also presents a 2D net. Moreover, the thermogravimetric and fluorescence properties of some compounds have been explored.