Multifunctional Cobalt(II) Coordination Polymers Tuned by Flexible Bis(pyridylamide) Ligands with Different Spacers and Polycarboxylates

Ten
multifunctional cobalt­(II) coordination polymers with the formulas
of [Co­(L1)0.5(5-AIP)]­·H2O (1), [Co­(L2)­(5-AIP)­(H2O)2] (2), [Co­(L3)0.5­(5-AIP)]
(3), [Co­(L4)0.5­(5-AIP)­(H2O)]­·2H2O (4), [Co­(L5)­(5-AIP)]
(5), [Co­(HBTC)­(L3)]­·H2O (6), [Co­(HBTC)­(L6)­(H2O)]­·3H2O (7), [Co­(L2)­(1,3-BDC)­(H2O)2] (8), [Co2(L3)2­(1,3-BDC)2]­·4H2O (9), and [Co2(L4)1.5­(1,2-BDC)­(μ2-OH)­(μ3-OH)­(H2O)]­·H2O (10) have been prepared by a hydrothermal technique employing
six flexible bis­(pyridylamide) ligands with different spacers (L1 = N,N′-bis­(3-pyridyl)­oxamide, L2 = N,N′-bis­(3-pyridyl)­malonamide, L3 = N,N′-di­(3-pyridyl)­succinamide, L4 = N,N′-bis­(3-pyridyl)­adipamide, L5 = N,N′-bis­(3-pyridyl)­heptandiamide, L6 = N,N′-bis­(3-pyridyl)­sebacicdiamide) and four aromatic polycarboxylic
acids mixed ligands (5-H2AIP = 5-aminoisophthalic acid,
H3BTC = 1,3,5-benzenetricarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, and 1,2-H2BDC = 1,2-benzenedicarboxylic
acid). Compound 1 exhibits a two-dimensional (2D) double-layer
network. Compounds 2 and 8 are isostructural
and possess one-dimensional (1D) circle-connecting-circle chain structures
derived from 1D [Co­(L2)]n “Ω”-like chain and 1D
[Co­(5-AIP)]n­/[Co­(1,3-BDC)]n wavelike chain. Compound 3 possesses
a 3,8-connected three-dimensional (3D) coordination framework with
{42.6}2­{44.610.79.85} topology. Compound 4 is a 2D
network containing a ladder-like chain. Compound 5 reveals
a novel 3-fold interpenetrating CdSO4-like framework. Compound 6 is a double-layer coordination network with a (3,5)-connected
{42·67·8}­{42·6} topology.
Complex 7 shows a 2D (4,4) grid layer. Compound 9 features a 2-fold interpenetrating 3D α-Po-related
topological framework. Compound 10 is a 6-connected 3D
coordination polymer with a {412.63} topology.
The spacer length of the bis­(pyridylamide) ligands, as well as the
substituent group and carboxyl group number of polycarboxylates, shows
a significant effect on the ultimate architectures of various cobalt­(II)
compounds 1–10. The electrochemical
behaviors of carbon paste electrodes (CPEs) bulk-modified by compounds 1–10 and the electrocatalytic activities
of 1-, 6-, 9-, 10-CPEs have been investigated. The photocatalytic properties of compounds 1–10 toward the degradation of methylene
blue (MB) in visible light irradiation have been investigated. The
variable temperature magnetic susceptibilities for compounds 3, 5, 9, and 10 indicate
the existence of antiferromagnetic exchange interactions.