Synthesis, Crystal Structure, and Luminescence of Zn/Cd Coordination Polymers with a New Fuctionalized Terpyridyl Carboxylate Ligand

Eight
new coordination polymers, [Zn­(L)­Cl]n (1), [Zn2(L)4]n·2nH2O (2), [Zn2(L)2(1,3-bdc)]n (3), [Zn2(L)­(1,3-bdc)­(OH)]n·0.5nH2O (4),
[Zn9(L)4(1,3-bdc)6(OH)2]n·3nH2O (5), [Zn2(L)2(1,4-bdc)]n·nH2O (6), [Cd2(L)4]n·nH2O (7), and
[Cd3(L)2(1,3-bdc)2]n·nH2O (8) [HL
= 4′-(2-carboxyphenyl)-4,2′:6′,4″-terpyridine,
H2(1,3-bdc) = benzene-1,3-dicarboxylic acid, H2(1,4-bdc) = benzene-1,4-dicarboxylic acid] have been synthesized
under hydrothermal conditions and characterized by elemental analysis,
IR, and single crystal X-ray diffraction. Complexes 1, 2, and 7 display a two-dimensional (2D)
layer structure. Complex 3 presents a complicated 2D
layer structure with paddle-wheel units, which exhibits an interesting
(3,4,6)-connected 3-nodal new topological net with the point symbol
of (3·4·5·62·7)2(3·6·7)2(32·42·52·62·76·8). Complex 4 is a 2-nodal
(3,5)-connected 2D bilayer structure with the gek1 topological
net and the point symbol of (3·4·5)­(32·4·5·62·74). Complex 5 shows a self-penetrating
three-dimensional (3D) framework based on pentanuclear clusters, which
features an intriguing (3,3,4,4,12)-connected 5-nodal new topological
net with the point symbol of (4·62)2(42·64)4(43)2(48·634·822·102). Complex 6 features a 2-fold interpenetrating
(3,4)-connected 3D framework with the ins topological
net and the point symbol of (63)­(65·8).
Complex 8 is a new (4,4,5,6)-connected 3D network built
up by a linear Cd3(COO)6 trinuclear cluster
with the point symbol of (42·63·8)2(43·63)2(44·64·82)2(48·66·8). The diverse structures indicate that
rational adjustment of the second ligand, the pH value, and counteranion
are good methods to further design metal–organic compounds
with new structures and properties. In addition, the thermal stabilities
and photoluminescence properties of 1–8 were also studied.