Work

Proton‐Exchange Rates on Hydroxide Bridges of Mineral‐Like Metal‐Hydroxide Clusters

Year: 2016

Type: article

Abstract: Soluble metal‐hydroxide clusters of Group 13 metals are popular in both materials chemistry and geochemistry. In geochemistry these clusters are used as experimental models for clay‐like minerals. In materials chemistry these clusters are the precursors for useful thin films. However, little is known about the formation mechanisms and solution dynamics of these species or how they compare to monomer ions. In this study we use 1 H‐NMR spectroscopy to estimate the exchange rates of protons on sites in the Ga 13 (μ 3 ‐OH) 6 (μ 2 ‐OH) 18 (H 2 O) 24 (NO 3 ) 15 ( Ga 13 ) and Ga 7 In 6 (μ 3 ‐OH) 6 (μ 2 ‐OH) 18 (H 2 O) 24 (NO 3 ) 15 ( Ga 7 In 6 ) cluster species. To date, these clusters provide the best molecular‐scale models for the surface chemistry of thin films and layered minerals. Trivalent metal‐hydroxide minerals are environmentally important, because of the rich acid‐base chemistry that exists in the pH regions of most soils. Our data suggest millisecond timescales for the exchange of protons on the μ 2 ‐OH bridges with bulk water in Group 13 metal‐hydroxide minerals, such as tsumgallite and diaspore.

Source: ChemistrySelect

DOI: 10.1002/slct.201600190

Authors: Caitlyn R. Fields, Anna F. Oliveri, Christopher A. Colla, Darren W. Johnson, William H. Casey

Institutions: University of Oregon, University of California, Davis

Language: English

Topic: Layered Double Hydroxides Synthesis and Applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, University of Oregon, Division of Chemistry

Awards: MRI: Acquisition of High-sensitivity NMR Capabilities for the University of Oregon Magnetic Resonance Facility, MRI: Acquisition of High Sensitivity 500 MHz NMR for the University of Oregon CAMCOR NMR Facility, Center for Sustainable Materials Chemistry