Network diversity and supramolecular isomerism in copper(II)/1,2-bis(4-pyridyl)ethane coordination polymers

Reactions of copper(II) sources with 1,2-bis(4-pyridyl)ethane (bpe) yielded metal–organic networks with diverse topologies and dimensionalities. Compounds [Cu(bpe)2(dmf)2]n(ClO4)2n·2ndmf (1·2ndmf), [Cu(bpe)2(dmf)2]n(ClO4)2n·3.5ndmf (2·3.5ndmf), [Cu(bpe)2(NO3)2]n·2nH2O (4·2nH2O) and [Cu2(bpe)(O2CMe)4]n·0.7nH2O (5·0.7nH2O) have been isolated by altering the copper(II) source, the reaction solvent and the crystallization process. Compounds 1·2ndmf and 2·3.5ndmf consist of cationic [Cu(bpe)2(dmf)2]2+ repeating units assembled to 1D and 2D (4,4) networks, respectively, and represent supramolecular isomers due to the conformational isomerism of the bridging bpe molecules. Compound 4·2nH2O consists of neutral mononuclear [Cu(dpe)2(NO3)2] repeating units assembled to inclined interpenetrating (4,4) sheets describing an overall entanglement that is 3D in nature, and compound 5·0.7nH2O consists of neutral dinuclear repeating units assembled to cross-linked 1D chains.

The use of 1,2-bis(4-pyridyl)ethane (bpe) in copper(II) chemistry has led to coordination polymers with diverse topologies and chemical compositions, i.e. the supramolecular isomers 1D [Cu(bpe)2(dmf)2]n(ClO4)2n·2ndmf (1·2ndmf) and 2D (4,4) weave-like sheets [Cu(bpe)2(dmf)2]n(ClO4)2n·3.5ndmf (2·3.5ndmf) as well as 3D inclined interpenetrating (4,4) sheets [Cu(bpe)2(NO3)2]n·2nH2O (4·2nH2O) and cross-linked 1D [Cu2(bpe)(O2CMe)4]n·0.7nH2O (5·0.7nH2O) have been prepared and structurally characterized.Figure optionsDownload as PowerPoint slideResearch highlights
► Conformational isomer’s influence on network dimensionality and diversity.
► Anion and solvent dependent network dimensionality and structural topology.
► New multi-dimensional meta-organic networks of flexible pyridine derivatives.