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.

八种新型配位聚合物，[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)以及[Cd3(L)2(1,3-bdc)2]n·nH2O (8)（其中HL = 4′-(2-羧基苯基)-4,2′:6′,4″-三吡啶，H2(1,3-bdc) = 苯-1,3-二羧酸，H2(1,4-bdc) = 苯-1,4-二羧酸）在高温高压条件下合成，并通过元素分析、红外光谱和单晶X射线衍射进行了表征。复合物1、2和7展现出二维（2D）层状结构。复合物3呈现出复杂的2D层状结构，包含浆状轮单元，并呈现有趣的(3,4,6)连通的三节点新型拓扑网络，其点符号为(3·4·5·62·7)2(3·6·7)2(32·42·52·62·76·8)。复合物4是一种2节点(3,5)连通的2D双层结构，具有gek1拓扑网络和点符号(3·4·5)­(32·4·5·62·74)。复合物5基于五核簇展示出自穿透的三维（3D）框架，其特征为引人入胜的(3,3,4,4,12)连通的五节点新型拓扑网络，点符号为(4·62)2(42·64)4(43)2(48·634·822·102)。复合物6具有2重交错的(3,4)连通的3D框架，其拓扑网络为ins，点符号为(63)­(65·8)。复合物8是由线性Cd3(COO)6三核簇构建的新型(4,4,5,6)连通的3D网络，点符号为(42·63·8)2(43·63)2(44·64·82)2(48·66·8)。这些多样化的结构表明，通过合理调整第二配体、pH值和反离子，是进一步设计具有新型结构和性质金属-有机化合物的有效方法。此外，还对1至8的热稳定性和光致发光性能进行了研究。