Fabrication of two supramolecular self-assemblies of Mn(II)-dicarboxylates with trans-4,4′-azobispyridine: Analysis of H-bonding interactions with Hirshfeld surfaces and DFT calculations

• Qualitative and quantitative determination of hydrogen bonding.
• The hydrogen bonding interaction recognizes two different dicarboxylates.
• The supramolecular interactions directs the formation of coordination structure.

Reactions with an aliphatic dicarboxylate (oxalate) as well as an aromatic dicarboxylate (terepthalate) in combination with an N,N′ donor ligand (trans-4,4′-azobispyridine) results two new coordination polymer of divalent manganese, namely {[Mn(azbpy)(H2O)4]·(bdc)·(H2O)2}n, (1) and {[Mn(ox)(H2O)2]·(azbpy)·(H2O)2}n,(2). Both the coordination polymers have one dimensional structure and extended to two-dimension by means of H-bonding. Interestingly, in solid state structure, the hydrogen bonding interaction recognizes the dicarboxylate (bdc) in case of 1 and N donor ligands (azbpy) in 2. The variation in the use of dicarboxylates, creates here a huge variation in the co-ordination modes of the metal ion as well as in the supramolecular structure within the crystal of 1 and 2. The contribution of various types of non-covalent forces are quantitatively explained in the light of Hrishfield surface analysis, which justifies the role of hydrogen bonding in the recognition of the above organic linkers. A DFT calculation of NBO also gives a quantitative understanding of the formation of the solid state structure by H-bonding. A thermogravimetric analysis, solid state fluorescence spectra and EPR spectroscopic study of the complexes have also performed which also nicely corroborated their crystal structures.

Two new supramolecular self assembly of Mn(II) have been designed with an aliphatic as well as an aromatic dicarboxylate in combination with an N,N′ donor ligand. The variation in the use of different dicarboxylates, creates a huge variation in the co-ordination modes of the metal ion as well as in their supramolecular structure.Figure optionsDownload as PowerPoint slide