Synthesis, Structure, and Magnetic Properties of Crystalline Coordination Polymers of Copper(II), {[Cu(CA)(H₂O)₂ (H₂O)}n AND [Cu(CA)(MeOH)₂ n (H₂CA; Chloranilic Acid)

Hydrogen bonded coordination polymers, {[CU(CA)(H2O)2 (H2O)}n, [Cu(CA)(MeOH)2 n (H2CA; chloranilic acid), and related polycrystalline analogs have been structurally and magnetically characterized. 1-Dimensional (1-D) weak antiferromagnetic exchange interaction (J = -2.01 cm−1) was observed in {[Cu(CA)(H2O)2 (H2O)}n, which has a 3-dimensional hydrogen bond network in the crystal. This polycrystalline form liberates the water molecules to be [Cu(CA) n, which is known as the Heisenberg antiferromagnet. Powder X-ray diffraction and thermal data show that the framework constructed by 1-D chains are so stable that water molecules readily come out without breaking the 1-D chains. Two types of coordination polymers ([Cu(CA)(MeOH)2 n and [Cu(CA)(MeOH) n) containing axially coordinated MeOH have been prepared. [Cu(CA)(MeOH) n has strong and anomalous antiferromagnetic exchange interactions in the crystal, indicating a new phase of Cu/CA systems, such as a mixed valence state, and if so the coordinated MeOH plays an important role to control physical properties of the polymers.