Wang Xin-Yi, Sevov Slavi C
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Inorg Chem. 2008 Feb 4;47(3):1037-43. doi: 10.1021/ic701893z. Epub 2007 Dec 21.
Three hybrid organic-inorganic coordination polymers with benzenepentacarboxylate (BPCA) linkers, [Co3(C6H(COO)5)(OH)(H2O)3] (1-Co), [Zn3(C6H(COO)5)(OH)(H2O)3] (2-Zn), and [Co5(C6H(COO)5)2(H2O)12].(H2O)12 (3-Co), were synthesized hydrothermally and were characterized structurally and magnetically. 1-Co and 2-Zn are isostructural [C2/c; Z=8; 1-Co, a=19.5350(6) A, b=10.4494(4) A, and c=13.2353(5) A, beta=97.2768(8) degrees; 2-Zn, a=19.5418(9) A, b=10.3220(10) A, and c=13.4660(10) A, beta=98.455(10) degrees] with three-dimensional structures that contain [M6] secondary building units bridged by BPCA ligands. A different cobalt-based compound, 3-Co, forms at lower pH and lower reaction temperature. Its structure [P21/c; Z=2; a=12.6162(2) A, b=11.3768(2) A, and c=15.3401(3) A, beta=91.539(1) degrees] is a more loosely packed framework with free (noncoordinated) carboxylic groups pointing at water-filled cavities in the framework. The magnetic phase diagram of 1-Co established through detailed magnetic measurements shows a metamagnetic transition below TN=3.8 K. The less-packed compound 3-Co, on the other hand, remains paramagnetic above 1.9 K. The three compounds are the first examples of coordination polymers with benzenepentacarboxylate linkers and fill the gap of coordination polymers involving benzenepolycarboxylate linkers of the general type C6H6-n(COOH)n, where n=2-6.
通过水热法合成了三种具有苯五羧酸酯（BPCA）连接体的有机-无机杂化配位聚合物，即[Co3(C6H(COO)5)(OH)(H2O)3]（1-Co）、[Zn3(C6H(COO)5)(OH)(H2O)3]（2-Zn）和[Co5(C6H(COO)5)2(H2O)12].(H2O)12（3-Co），并对其进行了结构和磁性表征。1-Co和2-Zn是同构的[C2/c；Z = 8；1-Co，a = 19.5350(6) Å，b = 10.4494(4) Å，c = 13.2353(5) Å，β = 97.2768(8)°；2-Zn，a = 19.5418(9) Å，b = 10.3220(10) Å，c = 13.4660(10) Å，β = 98.455(10)°]，具有三维结构，其中包含由BPCA配体桥连的[M6]二级结构单元。另一种基于钴的化合物3-Co在较低的pH值和较低的反应温度下形成。其结构[P21/c；Z = 2；a = 12.6162(2) Å，b = 11.3768(2) Å，c = 15.3401(3) Å，β = 91.539(1)°]是一种堆积较松散的框架结构，其中游离（未配位）的羧基指向框架中充满水的空穴。通过详细的磁性测量建立的1-Co的磁相图显示在TN = 3.8 K以下存在变磁转变。另一方面，堆积较松散的化合物3-Co在1.9 K以上保持顺磁性。这三种化合物是具有苯五羧酸酯连接体的配位聚合物的首个实例，填补了涉及通式为C6H6-n(COOH)n（其中n = 2 - 6）的苯多羧酸酯连接体的配位聚合物的空白。
