Structural Persistence Masks Commit-Point Chemical Transformation in Copper-Imidazolate Nanosheet Metal-Organic...

Area of Science:

• Environmental chemistry
• Materials science
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) stability is crucial for applications.
• Current stability assessments often use end-point metrics.
• The chemical identity of MOFs can change over time in aqueous environments.

Purpose of the Study:

• To investigate the transformation of nanoscale copper-imidazolate (CuIm) MOFs.
• To understand MOF stability across different aqueous matrices.
• To correlate structural changes with chemical identity evolution.

Main Methods:

• Time-resolved speciation analysis of copper-centered species.
• Separation of particle-associated and dissolved fractions.
• Exposure of CuIm MOFs to borehole water, artificial seawater, and cell-culture medium.

Main Results:

• CuIm MOFs showed matrix-dependent transformation rates.
• Rapid transformation occurred in cell-culture medium within 4 hours.
• Copper mobilization varied with matrix, indicating medium-specific reactivity.
• Structural signatures can persist despite altered surface chemistry.

Conclusions:

• CuIm MOF transformation follows matrix-selected trajectories with early shifts.
• Stability assessments require time-resolved chemical identity analysis, not just end-point crystallinity.
• Environmental conditions significantly impact MOF stability and behavior.