Chiral probes for α1-AGP reporting by species-specific induced circularly polarised luminescence† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c8sc00482j

Luminescence spectroscopy has been used to monitor the selective and reversible binding of pH sensitive, macrocyclic lanthanide complexes, [LnL1], to the serum protein α1-AGP, whose concentration can vary significantly in response to inflammatory processes.

Gaussian 09 (Revision D.01) program was used for geometry optimization and frequency calculations. [1] Density functional theory (DFT) method M06-2X [2] with cc-pVDZ basis set [3] and Stuttgart ECP [4] for the lanthanide ion were employed. Solvent effects were accounted with using the Solvation Model based on Density (SMD) parameterisation for the continuum model [5] of water. An additional empirical dispersion correction GD3 [6] was introduced to account for weak interactions. Real harmonic frequencies ensured that the optimized structures are local minima on their respective potential energy surfaces.
where the shift is in the units of ppm, coordinates are defined relative to the lanthanide in Å, components of the traceless part of the susceptibility tensor are in the units of Å 3 in SI system. Atomic coordinates were taken from DFT optimized geometries, and for methyl groups the structural functions were averaged assuming their fast rotation. Since PCS depends linearly on five components of the susceptibility tensor, the robust linear regression with 'bisquare' weight function as implemented in MATLAB R2017a was used to fit their values. The permutation with the largest adjusted Pearson coefficient was taken as the best fit. Using the best-fit χ tensor, the PCS values for all other protons have been predicted. The line widths were fitted using a simple isotropic model: where the constants C 1 and C 2 were fitted for the assigned signals and used to predict linewidth for all other protons. We have used total shift vs. width plots of predicted and experimentally observed signals for further assignment. Well-isolated groups of experimental signals were assigned to closely located

Chem Sci 2018
Shuvaev/Suturina/Mason/Parker groups of predicted signals and all possible permutations within the groups were checked, the assignment that gave the largest adjusted Pearson coefficient was chosen as the best fit.
The source code for this procedure will be released in Spinach version 2.2. [7] The best-fit susceptibility tensors are presented in the main text as axiality, rhombicity and three Euler angles. We use the following convention for defining axiality, rhombicity and Euler angles of a traceless susceptibility tensor. Diagonalisation of a traceless susceptibility tensor gives eigenvalues and eigenvectors which are labelled to satisfy the relation |χ x |<|χ y |<|χ z |. Then axiality is defined as 3/2 χ z and rhombicity as (χ x -χ y )/2. In such a definition, axiality and rhombicity have the same sign and the limiting value of the ratio of rhombicity to axiality is 1/3 (0<χ rh /χ ax <1/3).

Synthesis
The DO2A-ethyl ester [8] was synthesised according to previously reported procedures,.

Fig. S9
Comparison between CPL spectra recorded for [EuL 1 ] in the presence of human and bovine α 1 -AGP at pH = 9.30 (left) and CPL spectra of serum-albumin bound Eu tetraazatriphenylene complexes reported earlier [10] ; here the Δ(δδδδ) [EuL 1 ] enantiomer (blue/blue) is hypothesised to bind preferntially with added bovine α 1 -AGP, and the Λ(λλλλ) enantiomer (black/red) may be preferentially bound when [EuL 1 ] is added to human α 1 -AGP.              Molecular frames of optimized geometries have been unified so that the origin is located at the lanthanide position, the z--axis is pointing into the middle of the four nitrogen atoms of the cyclen ring, and the x--axis is pointing at the first nitrogen atom of the cyclen, located under the pyridine.   (3) Table 3, and in the main text, the best--fit susceptibility tensors are presented as axiality, rhombicity and three Euler angles. We use the following convention for defining axiality, rhombicity and Euler angles of a traceless susceptibility tensor. Diagonalisation of a traceless susceptibility tensor gives eigenvalues and eigenvectors which are labelled to satisfy the relation |χ x |<|χ y |<|χ z |. Then axiality is defined as 3/2 χ z and rhombicity as (χ x -- χ y )/2. In such a definition, axiality and rhombicity have the same sign and the limiting value of the ratio of rhombicity to axiality is 1/3 (0<χ rh /χ ax <1/3).