Cyclometalation of lanthanum(iii) based MOF for catalytic hydrogenation of carbon dioxide to formate

Piwai Tshuma; Banothile C E Makhubela; Lars Öhrström; Susan A Bourne; Nabanita Chatterjee; Isaac N Beas; James Darkwa; Gift Mehlana

doi:10.1039/c9ra09938g

Cyclometalation of lanthanum(iii) based MOF for catalytic hydrogenation of carbon dioxide to formate

RSC Adv. 2020 Jan 22;10(6):3593-3605. doi: 10.1039/c9ra09938g. eCollection 2020 Jan 16.

Authors

Piwai Tshuma^{1

2}, Banothile C E Makhubela², Lars Öhrström³, Susan A Bourne⁴, Nabanita Chatterjee⁴, Isaac N Beas⁵, James Darkwa^{2

5}, Gift Mehlana¹

Affiliations

¹ Department of Chemical Technology, Faculty of Science and Technology, Midlands State University Private Bag 9055, Senga Road Gweru Zimbabwe.
² Department of Chemistry, Faculty of Science, University of Johannesburg, Kingsway Campus: C2 Lab 328 Auckland Park 2006 South Africa.
³ Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Physical Chemistry Room 9029 Göteborg Sweden.
⁴ University of Cape Town, Department of Chemistry, Faculty of Science PD Hahn Building 7701 Rondebosch Cape Town South Africa.
⁵ Department of Natural Resources and Materials, Botswana Institute of Technology Research and Innovation Maranyane House Private Bag 0082 Gaborone Botswana mehlanag@staff.msu.ac.zw.

Abstract

The hydrogenation of carbon dioxide (CO₂) to formic acid is of great importance due to its useful properties in the chemical industry. In this work, we have prepared a novel metal-organic framework (MOF), JMS-1, using bipyridyl dicarboxylate linkers, with molecular formula [La₂(bpdc)₃(DMF)₃] _n . Network analysis of JMS-1 revealed a new 7-connected topology (zaz). The MOF backbone of the activated phase (JMS-1a) was functionalized by cyclometalation using [RuCl₂(p-cymene)]₂ to produce Ru(ii)@JMS-1a. Both JMS-1a and Ru(ii)@JMS-1a were able to convert CO₂ in the presence of hydrogen to formate. Ru(ii)@JMS-1a displayed outstanding conversion evidenced by a yield of 98% of formate under optimized conditions of total pressure 50 bar (CO₂/H₂ = 1 : 4, temperature 110 °C, time 24 h, 5 mmol KOH, 8 mL ethanol). This work is significant in providing new strategies of incorporating active catalytic centres in MOFs for efficient and selective conversion of CO₂ to formate.