Shape-independent model (SHIM) approach for studying aggregation by NMR diffusometry

Area of Science:

• Applied Chemistry
• Physical Chemistry
• Analytical Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) diffusometry is widely used for studying diffusion and complexation.
• Current methods for analyzing aggregation beyond dimers require prior knowledge of aggregate shapes, which is often impractical.
• This limitation restricts the application of NMR diffusometry to complex assembly processes.

Purpose of the Study:

• To analyze the dependency of aggregation parameters on the chosen model shapes.
• To develop a novel, shape-independent model for NMR diffusometry of aggregation.
• To provide an alternative method for determining aggregation parameters when aggregate shapes are unknown.

Main Methods:

• Comprehensive analysis of aggregation parameter dependency on shape.
• Development and application of a shape-independent model (SHIM approach).
• Utilizing self-diffusion NMR data for analysis.

Main Results:

• Demonstrated the impact of shape selection on aggregation parameter determination.
• Introduced the SHIM approach, a shape-independent model for aggregation analysis.
• Successfully applied the model to determine equilibrium aggregation parameters from NMR data.

Conclusions:

• The SHIM approach overcomes the limitation of needing prior knowledge of aggregate shapes in NMR diffusometry.
• This model facilitates the study of complex aggregation phenomena beyond the dimer stage.
• Enables accurate determination of equilibrium self-association constants, enthalpy, and entropy changes.