A Unique Layered Cu-formate Hydrate of Cu(HCOO)2·1/3H2O:Structures,Dehydration,and Thermal and Magne

• 作 者: FAN Huimin WANG Bingwu WANG Zheming GAO Song
• 机 构: Beijing National Laboratory for Molecular Sciences,College of Chemistry and Molecular Engineering,Pe
• 出 处: 高等学校化学研究（英文版）
• 发表日期: 2022年1期
• 关键词: Copper formate Layered structure Dehydration Thermal expansion Magnetism

A new layered Cu-formate hydrate of Cu(HCOO)2·1/3H2O is unique in its water content and the strongly waved (4,4)Cu-formate layers held by interlayer weak axial Cu-Oformate bonds and O-Hwater…Oformate hydrogen bonds.The crystal is in orthorhombic space group Pbcn,with cell parameters at 80 K:a=7.9777(2) (A),b=7.3656(2) (A),c=21.0317(5) (A)(1 (A)=1.0-1 nm),and V=1235.83(5) (A)3.The Cu2+ ions are in the environments of a square pyramid and elongated octahedron,in a ratio of 1/2 within the structure.In the layer,Cu2+ ions are connected by anti-anti formates via short basal Cu-O bonds.The structure remains unchanged until the dehydration that produces the layered anhydrous β-Cu(HCOO)2,and the possible transformation mechanism,supported by diffraction evidence,is the reorganization of the Cu-Oformate bonds across the parent layers after dehydration.The two phases exhibit anisotropic thermal expansion behaviors closely relevant to the transverse thermal vibrations of the constituents.Cu(HCOO)2·1/3H2O is a 2-dimensional Heisenberg antiferromagnet,and exhibits a global spin-canted antiferromagnetism with the Néel temperature of 32.1 K.This is not only higher than that of the magnetically denser β-Cu(HCOO)2,but also the highest among the copper formate frameworks.