Palanisamy Rajakannu

Design strategy for arranging an aromatic cyclic trimer into a tripodal molecule

Arranging an aromatic cyclic trimer into a tripodal molecule was achieved by the reaction of tri(bromomethyl)benzene with substituted benzimidazoles. The edge-to-face C–H⋯π interactions in the trimer stabilize the conformation of flexible molecules.

Synthesis and crystal structure of a wheel-shaped supramolecular coordination complex

AbstractSupramolecular coordination complex (SCC) possessing spatially arranged three anthraquinone dimers in a slipped-cofacial orientation was achieved by the treatment of Re2(CO)10, 2-hydroxymethylanthraquinone and tritopic N-donor via fac-Re(CO)3-directed one pot approach. The off-set π-stacking and C≡O···H bonding interactions stabilize the ring structure. Graphical AbstractSupramolecular coordination complex (SCC) possessing spatially arranged three anthraquinone dimers in a slipped-cofacial orientation was achieved by the treatment of Re2(CO)10, 2-hydroxymethylanthraquinone and tritopic N-donor via fac-Re(CO)3-directed one pot approach. The offset π-stacking and C≡O···H bonding interactions stabilize the ring structure.

Steric group enforced aromatic cyclic trimer conformer in tripodal molecules

A family of tripodal molecules (1–6) with/without steric ethyl groups at the central benzene scaffold and with furan/thiophene/pyridyl group at the 2-position of the benzimidazolyl unit was synthesised. Compounds 1–6 were characterized by elemental analysis and NMR spectroscopy. Compounds 1, 3, and 5 were further characterized by single crystal X-ray diffraction analysis. The molecular structures of 1 and 4 were optimized using density functional theory (DFT) calculations. X-ray and 1H NMR studies reveal that the introduction of three ethyl groups into a central benzene scaffold of furan/thiophene/pyridyl substituted benzimidazolyl based tripodal molecules enhances the edge-to-face C–H⋯π interactions, thereby favouring the aromatic cyclic trimer motif, in solution and the solid state. The unsubstituted central benzene scaffold allows the furan/thiophene substituted benzimidazolyl units in the tripodal molecules to move freely thereby weakening the edge-to-face C–H⋯π interactions between the aromatic cyclic trimer motif. Molecular modelling calculations indicate that the energy minimized structures of the tripodal molecules adopt a symmetric cyclic aromatic motif conformation.

4,4′-Bipyridine–3-(thio­phen-3-yl)acrylic acid (1/2)

In the title 1/2 adduct, C10H8N2·2C7H6O2S, the dihedral angle between the pyridine rings is 18.41 (11)°. In the thiopheneacrylic acid molecules, the dihedral angles between the respective thiophene and acrylic acid units are 5.52 (17)° and 23.92 (9)°. In the crystal, the components are linked via O—H⋯N hydrogen-bonding interactions, forming units of two 3-thiopheneacrylic acid molecules and one 4,4′-bipyridine molecule.