Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties

Abstract

Using 1,2,3,5-benzenetetracarboxylic acid and different pyridyl ligands, three metal-organic coordination compounds, [ $$\hbox {Co(H}_{3}\hbox {btec})(1{,}{10}\hbox {-phen})(\hbox {H}_{2}\hbox {O})_{3}$$ ][OH] $$\cdot 2\hbox {H}_{2}\hbox {O}$$ (1), [ $$\hbox {Co}_{2}$$ (btec)(2,2’-bipy) $$_{2}$$ - ( $$\hbox {H}_{2}\hbox {O}$$ )] $$\cdot \hbox {H}_{2}\hbox {O}$$ (2), {[ $$\hbox {Co}_{1.5}(\hbox {H}_{2}\hbox {btec}$$ )(4,4’-bipy)( $$\hbox {H}_{2}\hbox {O})_{2}$$ ][ $$\hbox {Co}_{0.5}$$ (4,4’-bipy)- ( $$\hbox {H}_{2}\hbox {O})_{4}][\hbox {OH}]_{2}\}\cdot 2\hbox {H}_{2}\hbox {O}$$ (3), ( $$\hbox {H}_{4}\hbox {btec} = 1,2,3,5$$ -benzenetetracarboxylic acid, 1,10-phen = 1,10-phenanthroline, 2,2’-bipy = 2, $$2^{\prime }$$ -bipyridine, 4,4’-bipy = 4, $$4^{\prime }$$ -bipyridine) were synthesized by hydrothermal method and characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. X-ray crystallographic studies reveal that 1 is a discrete 0D coordination compound, while 2 and 3 possess similar 2D network structures, which show a sql network with the point symbol of (4,4). Thermal analysis indicates that compounds 1 and 2 begin to collapse after $$350{^{\circ }}\hbox {C}$$ . Further, the UV-Vis DRS spectra and solid-state luminescent properties of 1–3 have also been studied. SYNOPSIS The reaction of benzene tetracarboxylate $$\hbox {H}_{4}\hbox {btec}$$ and pyridyl ligands (1,10-phen, 2,2’-bipy, and 4,4’-bipy) gave rise to three coordination compounds, $$[\hbox {Co(H}_{3}\hbox {btec)}(1,10\hbox {-phen)(H}_{2}\hbox {O)}_{3}][\hbox {OH}]\cdot 2\hbox {H}_{2}\hbox {O}$$ , [ $$\hbox {Co}_{2}$$ (btec)(2,2’- $$\hbox {bipy})_{2}(\hbox {H}_{2}\hbox {O})]\cdot \hbox {H}_{2}\hbox {O}$$ , $$\{[\hbox {Co}_{1.5}(\hbox {H}_{2}\hbox {btec})$$ (4,4’ $$-\hbox {bipy})(\hbox {H}_{2}\hbox {O})_{2}$$ ][ $$\hbox {Co}_{0.5}$$ (4,4’-bipy)( $$\hbox {H}_{2}\hbox {O})_{4}][\hbox {OH}]_{2}\}\cdot 2\hbox {H}_{2}\hbox {O}$$ , which exhibit discrete and 2D network structures, as shown.