Data analysis

The collected DOSY data were processed using SimFit algorithm as explained in standard Bruker DOSY data processing manual (Kerssebaum, R. DOSY and Diffusion by NMR. In User Guide for XWinNMR 3.5, Version 1.0; Bruker Buospin GmbH: Rheinstetten, Germany, 2002). The intensities extracted by SimFit algorithm were fit using a two-parameter monoexponential Eq. (4) in OriginPro 8.5.0 (OriginLab, Northamptan, MA, USA) to get the D for the solute molecule in the solvent that has been used in the study:

where I is the observed intensity, I₀ is the reference or unattenuated intensity, D the diffusion coefficient, γ the gyromagnetic magnetic ratio of the observed nucleus, g the gradient strength, δ the length of the gradient pulse, and Δ the diffusion time.

The ¹³C-T₁ relaxation data were processed and extracted as separate 1D corresponding to each recovery delay time, t. Peak picking was done in topspin3.2 (Bruker Biospin, GmbH: Rheinstetten, Germany). The intensity data were then fitted using Mathematica v5.2 (Wolfram Research, Inc., Champaign, IL, USA) script²⁷ to the following monoexponential decay function, to get the longitudinal relaxation time constant (T₁):

The error in the T₁ time was obtained as fit error the to the above Eq. (5) using both Monte Carlo simulations and repeat relaxation delay point from the Mathematica script.