Base-Resistant Ionic Metal-Organic Framework as a Porous Ion-Exchange Sorbent

Aamod V Desai,Arkendu Roy,Partha Samanta,Biplab Manna,Sujit K Ghosh

doi:10.1016/j.isci.2018.04.004

Aamod V Desai, Arkendu Roy + Show 3 more

Open Access

https://doi.org/10.1016/j.isci.2018.04.004

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Abstract

SummaryA systematic approach has been employed to obtain a hydrolytically stable cationic metal-organic framework (MOF). The synthesized two-dimensional Ni(II)-centered cationic MOF, having its backbone built from purely neutral N-donor ligand, is found to exhibit uncommon resistance over wide pH range, particularly even under highly alkaline conditions. This report presents a rare case of a porous MOF retaining structural integrity under basic conditions, and an even rarer case of a porous cationic MOF. The features of stability and porosity in this ionic MOF have been harnessed for the function of charge- and size-selective capture of small organic dye through ion-exchange process across a wide pH range.

Highlights

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have rapidly evolved as an important subset of porous materials (Long and Yaghi, 2009; Horike et al, 2009; Furukawa et al, 2013; Zhou and Kitagawa, 2014; Howarth et al, 2017; Maurin et al, 2017)
Combining the above-mentioned facets, we report the synthesis of a two-dimensional (2D) Ni(II)centered cationic MOF, viz., [{Ni(L)2}$(BPSA)$xG]n (L is the ligand; BPSA is 4,40-biphenyldisulfonic acid; and G is the guest; it is hereafter referred to as IPM-MOF-201, where IPM stands for IISER Pune Materials)
Synthesis and Characterization of IPM-MOF-201 Hexagonal-shaped single crystals of compound IPM-MOF-201 were obtained in a solvothermal reaction at 130C from a mixture of NiSO4$xH2O, BPSA, and ligand (L) (1:1.5:1), in a solvent system of N,N0-dimethylformamide (DMF) and water (2:1) (Scheme S1; see Transparent Methods)

Summary

Introduction

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have rapidly evolved as an important subset of porous materials (Long and Yaghi, 2009; Horike et al, 2009; Furukawa et al, 2013; Zhou and Kitagawa, 2014; Howarth et al, 2017; Maurin et al, 2017). The proper choice of the metal ions or the suitable kind of the organic ligand have been found to play a crucial role in bestowing stability to a compound This formal outline has generally been derived from stable benchmark compounds, which in most cases are neutral MOFs. The systematic design and development of stable cationic MOFs from the insights gained in literature reports is extremely uncommon (Karmakar et al, 2016)

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