Aqueous syntheses of anthracene-based mixed-ligand coordination polymers and their structural and optical properties

Abstract

Series of mixed-ligand coordination polymers (CP) and metal–organic frameworks (MOFs) based on bulky 9,10-di(1H-imidazol-1-yl)anthracene (dia) were synthesized from aqueous solutions even with very short (<10 min) reaction times. Two different metals (M = Cu, Ni) and three different secondary ligands were used to generate six new structures: [Cu₂(dia)₂(5-aip)₂]·6H₂O (1), [Ni₂(dia)₂(5-aip)₂]·5H₂O (2), [Cu₂(dia)₂(2-ata)₂]·4H₂O (3), [Ni(dia)(2-ata)·Ni(dia)₂(2-ata)]·2.5H₂O (4), [Cu₈(dia)₂(5-sip)₄(OH)₄] (5) and [Ni₃(dia)₅(5-sip)₂]·6DMF·14H₂O (6). Structure analyses involving single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD) and Fourier-transform infrared spectroscopy (FT-IR) were conducted along with studies determining the thermal stabilities and optical properties of the compounds. The results indicate that the developed fast and green syntheses can produce pure CP and MOF phases that have various thermally stable and visible light absorbing structures which may find applications in photocatalysis.