Fumarato-bridged open layers: Syntheses and crystal structures of M(H₂O)₂L, with M = Cu, Cd and H₂L = fumaric acid

Abstract

Two fumarato-bridged coordination polymers M(H 2 O) 2 (C 4 H 2 O 4 ), with M ¼ Cu (1) and Cd (2), were prepared and structurally characterized using single-crystal X-ray methods. In 1, Cu atoms are coordinated by two aqua oxygen atoms at trans positions and three oxygen atoms of different fumarate anions to form a square pyramid; two adjacent CuO 5 square pyramids share edges to form Cu 2 O 8 dimers. Cd atoms in 2 are coordinated by seven oxygen atoms of two aqua ligands and three different fumarate anions to form a distorted pentagonal bipyramid, with two adjacent pentagonal bipyramids sharing a common edge to form Cd 2 O 12 dimers. Both dimers in 1 and 2 are bridged by fumarato ligands to generate open layers with a (4, 4) topology. Close packing of the layers prevents formation of porous 3D networks. The magnetic behavior of 1 was investigated.