An Fe-III dinuclear metallacycle complex as a size-selective adsorbent for nitrogenous compounds and a potentially effective ammonia storage material

Author(s)

Silva, Ingrid F. ^[1] ; Teixeira, Ivo F. ^{[2, 3]} ; Barros, Wdeson P. ^[4] ; Pinheiro, Carlos B. ^[5] ; Ardisson, Jose D. ^[6] ; do Nascimento, Gustavo M. ^[7] ; Pradie, Noriberto A. ^[3] ; Teixeira, Ana Paula C. ^[1] ; Stumpf, Humberto O. ^[1]

Affiliation

^[1] Univ Fed Minas Gerais, ICEx, Dept Quim, Ave Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Dept Quim, Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Ave Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

^[4] Univ Estadual Campinas, Inst Quim, BR-13083970 Campinas, SP - Brazil

^[5] Univ Fed Minas Gerais, ICEx, Dept Fis, BR-31270901 Belo Horizonte, MG - Brazil

^[6] CDTN, Lab Fis Aplicada, BR-31270901 Belo Horizonte, MG - Brazil

^[7] Univ Fed ABC, CCNH, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY A; v. 7, n. 25, p. 15225-15232, JUL 7 2019.
• Web of Science Citations: 2

Abstract

Ammonia has a large volume energy density and consequently high potential for application as a fuel and energy reservoir in the future. In this study, the dinuclear Fe-III metallacycle complex {[}Fe-2(H(2)opba)(2)Cl-2(dmso)(2)]center dot 2CH(2)Cl(2)center dot 2dmso (1) with excellent capacity to selectively adsorb ammonia (11.3 mmol g(-1)) was investigated, demonstrating a strong preference for nitrogenous compounds, especially short-chain amines. The adsorption results suggest that the cavity in the structure of 1 has an essential role in the adsorption mechanism i.e. it is the responsible for size selectivity of 1 during the adsorption process. To better understand the adsorption mechanism of ammonia, 1 was fully characterized before and after adsorption. Thermogravimetric-mass spectrometry (TG-MS) and ammonia isotherm experiments revealed that 8 ammonia molecules were physisorbed by the complex cavity (free ammonia) and 4 ammonia molecules were chemisorbed (coordinated ammonia) per dinuclear metallacycle unit. Further characterization also confirmed the proposed adsorption mechanism, corroborating the structural modification of the compound after its interaction with ammonia; in addition, reuse tests showed that despite a small loss of efficiency, the compound was capable of desorbing most of the ammonia and could be used consecutively for at least three cycles. Thus, 1 is a potential ammonia storage material and adsorbent for the removal of ammonia from effluents. (AU)

• FAPESP's process: 15/22379-7 - Multifunctional molecular magnetic systems: synthesis and study of magnetic, luminescent and photorreactive properties of polinuclear complexes containing transition and lanthanide metal ions
• Grantee: Wdeson Pereira Barros
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/05506-0 - Nanoengineering Materials for Plasmonic Photocatalytic Applications
• Grantee: Ivo Freitas Teixeira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral