期刊
JOURNAL OF SOLID STATE CHEMISTRY
卷 159, 期 2, 页码 352-361出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1006/jssc.2001.9164
关键词
structure; magnetism; crystal engineering; coordination polymer; dicyanamide; pyrazine; interpenetration
The coordination polymers [M(dca)(2)pyz] (M = Mn, Fe, Co, Ni, Zn) have been synthesized and characterized by single-crystal and powder X-ray diffraction, Two isomers have been observed, The alpha compounds contain two interpenetrating 3D alpha -Po related networks. Bidentate dca ligands bridge the metal atoms to form square-grid-like M(dca), sheets, with the pyrazine ligands linking these sheets together to form the alpha -Po-like 3D networks. The beta compounds contain interdigitated 2D sheets, The sheets consist of 1D chains of M(dca)(2) connected together by the pyrazine ligands. The alpha compounds display an interesting phase change that simultaneously induces twinning of the crystals. At room temperature the structures are orthorhombic Pnma and contain dynamic disorder of the dca ligands, However, on cooling (e.g., to 123 K) the structures become monoclinic P2(1)/n with the dca ligands ordered, but since domains within each crystal order differently, this results in pseudo-merohedral twinning. Variable temperature and variable field magnetic studies have shown that these compounds display weak antiferromagnetic coupling between the high-spin metal centers. Only in the case of alpha-[Mn(dca)(2)pyz] is there evidence for 3D antiferromagnetic order occurring below 2.7 K. (C) 2001 Academic Press.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据