Two novel 3D copper(II) complexes based on a rigid bis-pyridyl-bis-amide and two polycarboxylates mixed ligands: Assembly, structures and properties

摘要

Two novel three-dimensional (3D) copper(II) complexes [Cu _3(3-bpcb)(1,2-BDC)_2(μ_2-OH)_2] (1) and [Cu_2(3-bpcb)_(1.5)(SIP)(μ_3-OH)] ·H_2O (2), based on a rigid bis-pyridyl-bis-amide ligand [3-bpcb = N,N′-bis(3-pyridinecarboxamide)-1,4-benzene] and two different polycarboxylates [1,2-H_2BDC = 1,2-benzenedicarboxylic acid, NaH _2SIP = sodium 5-sulfoisophthalic acid] have been prepared under hydrothermal conditions. Single crystal X-ray diffraction analysis shows that complex 1 exhibits a 4-nodal mixed (3,4,4,5)-connected 3D structure with the (3·4·5)_2(3·4~2·5·8 ~6)_2(3~2·8·9~2·10) (4~2·8~2·10~2) Schl?fli symbol, which is constructed from two-dimensional (2D) Cu(II)-μ_2-OH-3- bpcb layers (3-bpcb: μ_4-bridging coordination mode via two pyridyl nitrogen and two carbonyl oxygen atoms) and the 1,2-BDC bridging ligands. Complex 2 is also a 3D coordination polymer constructed from the μ2-bridging 3-bpcb ligands (via two pyridyl nitrogen atoms) and the 2D Cu(II)-μ_3-OH-SIP sheets containing tetranuclear copper clusters, showing a novel 3-nodal (5,6,6)-connected (3~3·4 ~3·5~3·6~3·7 ~2·8)(3~3·4~3·5 ~3·6)(3~3·4~6·5 ~4·6~2) topology. The differences between the final 3D structures for complexes 1 and 2 might be attributed to the different aromatic polycarboxylates and the bis-pyridyl-bis-amide ligand with different coordination modes. Moreover, the electrochemical behavior of complex 1 and the fluorescence properties of the complexes 1-2 have been investigated.