Issue 89, 2016

Green synthesis, optical and magnetic properties of a MnII metal–organic framework (MOF) that exhibits high heat of H2 adsorption

Abstract

Green synthesis of a 3D, Mn(II) metal–organic framework (MOF) composed of a trimeric Mn(II) cluster and NDC linker formulated as [Mn3(NDC)3(DMA)4]n (1) (where, NDC = 2,6 napthalene dicarboxylic acid, DMA = N,N-dimethylacetamide) has been achieved by employing mechanochemical and sonochemical routes. Interestingly, MOF 1 undergoes reversible structural transformation upon desolvation and solvation of DMA molecules. The desolvated framework, 1′ containing two unsaturated Mn(II) sites exhibits interesting H2 and CO2 uptake properties with isosteric heats of adsorption (Qst) for H2 and CO2 of 11.8 and 29.2 kJ mol−1, respectively. Remarkably, the Qst of H2 estimated for 1′ is found to be the highest value amongst the Mn(II) MOFs reported so far and the high value has been attributed to the stronger interaction of H2 with the unsaturated Mn(II) centers. Further, variable temperature magnetic susceptibility measurements of 1 revealed weak antiferromagnetic coupling interactions between the adjacent Mn(II) ions. The thermal stability of 1 has also been examined and was found to be highly stable. Photoluminescence investigation revealed that the emission from MOF 1 is owed to ligand based charge transfer transitions. Furthermore, compound 1 undergoes temperature induced solid-state conversion into phase pure MnO nanocrystals of about 10–18 nm in size embedded in a carbonaceous layer to form MnO–C nanocomposite (NC). The MnO–C NC has been characterized by PXRD, FE-SEM, EDAX and TEM analyses.

Graphical abstract: Green synthesis, optical and magnetic properties of a MnII metal–organic framework (MOF) that exhibits high heat of H2 adsorption

Supplementary files

Article information

Article type
Paper
Submitted
13 iyl 2016
Accepted
03 sen 2016
First published
05 sen 2016

RSC Adv., 2016,6, 86468-86476

Green synthesis, optical and magnetic properties of a MnII metal–organic framework (MOF) that exhibits high heat of H2 adsorption

S. S. Dhankhar and C. M. Nagaraja, RSC Adv., 2016, 6, 86468 DOI: 10.1039/C6RA17898G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements