Assembly, photocatalytic and fluorescence properties of three new coordination complexes of zinc(II) and nickel(II) with two kinds of flexible bis(pyridyl)-bis(amide) ligands

Abstract Three new coordination complexes [Zn(btec) 0.5 (L 1 ) 0.5 (H 2 O)] n ( 1 ), [Ni(H 2 btec)(L 1 )(H 2 O) 2 ] n ( 2 ), and {[Ni(btec) 0.5 (L 2 )(H 2 O) 3 ]·2H 2 O} n ( 3 ) [H 4 btec = 1,2,4,5-benzenetetracarboxylic acid), L 1 = N , N ′-bis(3-pyridyl)adipamide, L 2 = N , N ′-bis(3-pyridyl)octanediamide] have been obtained under hydrothermal conditions. Single-crystal X-ray diffraction analysis has revealed that complex 1 has a layer structure based on [Zn(btec) 0.5 ] n ribbons and the μ 2 -bridging ligands L 1 . Complex 2 possesses a layered framework constructed by [Ni(H 2 btec)] n linear chains and [Ni(L 1 )] n wave-like chains. Complex 3 forms layers based on [Ni(L 2 )] n helical chains and μ 2 -bridging L 2 ligands, representing an interesting 4-fold interpenetrating 2D braided framework. The three different 2D frameworks exhibit 3,4-connected {4.6 2 } 2 {4 2 .6 2 .8 2 } topology for 1 , 4-connected {4 4 .6 2 } topology for 2 and 3-connected {6 3 } topology for 3 . Their adjacent layers are further linked by hydrogen bonding interactions to generate 3D supramolecular structures. The differences in the nature of both the metal ions and the organic ligands lead to various coordination modes in the final structures. The photocatalytic activities and the fluorescence properties of complexes 1 – 3 were investigated.