New 5,5-(1,4-Phenylenebis(methyleneoxy)diisophthalic Acid Appended Zn(II) and Cd(II) MOFs as Potent Photocatalysts for Nitrophenols.

Metal-organic frameworks (MOFs) are peculiar multimodal materials that find photocatalytic applications for the decomposition of lethal molecules present in the wastewater. In this investigation, two new d 10 -configuration-based MOFs, [Zn 2 (L)(H 2 O)(bbi)] ( 1 ) and [Cd 2 (L)(bbi)] ( 2 ) (5,5-(1,4-phenylenebis(methyleneoxy)diisophthalic acid (H 2 L) and 1,1'-(1,4-butanediyl)bis(imidazole) (bbi)), have been synthesized and characterized. The MOF 1 displayed a (4,6)-connected (3.4 3 .5 2 )(3 2 .4 4 .5 2 .6 6 .7) network topology, while 2 had a (3,10)-connected network with a Schläfli symbol of (4 10 .5 11 .6 22 .7 2 )(4 3 ) 2 . These MOFs have been employed as photocatalysts to photodegrade nitrophenolic compounds, especially p -nitrophenol (PNP). The photocatalysis studies reveal that 1 displayed relatively better photocatalytic performance than 2 . Further, the photocatalytic efficacy of 1 has been assessed by altering the initial PNP concentration and photocatalyst dosage, which suggest that at 80 ppm PNP concentration and at its 50 mg concentration the MOF 1 can photo-decompose around 90.01% of PNP in 50 min. Further, radical scavenging experiments reveal that holes present over 1 and ·OH radicals collectively catalyze the photodecomposition of PNP. In addition, utilizing density of states (DOS) calculations and Hirshfeld surface analyses, a plausible photocatalysis mechanism for nitrophenol degradation has been postulated.