A 3D chiral supramolecular framework of Cu(II): Synthesis, structure and magneto-structural correlations

A metal–organic coordination chain of Cu(II), viz {[Cu(Hbtc)(NH3)4](H2O)}n (1) (btc = benzenetricarboxylate) has been synthesized and structurally characterized. The sky blue single crystals of 1 were grown by the dissolution of the as-synthesized insoluble product obtained from the reaction of Cu(II), H3btc and 4,4′-bipy in aqueous NH3 solution. Structural determination reveals that 1 crystallizes chiral P212121 space group and 1D coordination chain of Cu(II) bridged by the Hbtc linker. 1D chains are H-bonded via the guest water molecules forming a 2D sheet like structure and 2D sheets through π–π and N–H···O H-bonding interactions produce a 3D supramolecular framework with 1D water filled channels along the a-axis. Temperature dependent magnetic measurement exhibits weak antiferromagnetic intrachain interaction between Cu(II) centers through the Hbtc linker with J = −0.17 cm−1 and g = 2.01 and at low temperature interchain ferromagnetic interaction is predominates. The dominant antiferromagnetic interaction is supported by the DFT calculations.

Graphical abstractA 3D chiral supramolecular framework constructed by the H-bonding and π–π interactions between the 1D coordination chain of Cu(II), {[Cu(Hbtc)(NH3)4](H2O)}n (1) (H3btc = benzene tricarboxylic acid) has been synthesized and structurally characterized. Low temperature magnetic measurement exhibits weak antiferromagnetic intrachain interaction between Cu(II) through the Hbtc ligand with J = −0.17 cm−1 and g = 2.01, which is supported by the DFT calculations.Figure optionsDownload full-size imageDownload as PowerPoint slide