Stereochemical assignment of the meridional isomer of the trisbidentate chelate complex Ga(fox)3 (fox = 5-fluoro-8-hydroxyquinoline) by two-dimensional correlated NMR

Thermodynamic N-Donor trans Influence in Labile Pseudo-Octahedral Zinc Complexes: A Delusion?

“…One also notes that, in the facial isomer, each donor atom N A of a given heterocycle lies trans to the N B donor atom of another aromatic ring thus leading to three trans N A –M–N B correlations. In the meridional isomer, a single heterotopic trans N A –M–N B arrangement occurs, together with two trans homotopic N A –M–N A and N B –M–N B correlations (Figure ) . Since electronic (spin-crossover), photophysical (energy gap, excited-state lifetime, quantum yield), electrochemical, and physical (metalorganic chemical vapor deposition) properties depend on the ligand-field strength and on the exact geometries around the metallic center, the control of the mer -[M L 3 ] ↔ fac -[M L 3 ] isomerization process is crucial for programming and optimizing the physicochemical characteristics of the final complex. , While the dynamics of the intimate mechanisms of mer↔mer and mer↔fac isomerization processes around various labile closed-shell metallic cations was the focus of comprehensive kinetic studies, ,, we cannot find reliable thermodynamic analysis of equilibrium (1) for labile octahedral complexes in solution except for the paramagnetic open-shell d 7 complex [Co( L1 ) 3 ] 2+ in acetonitrile …”

Improving the Sensitivity of FESTA Methods for the Analysis of Fluorinated Mixtures

“…In particular, the fact that 19 F is very sensitive to chemical environment makes 19 F resonate over a wide range of chemical shift (around 500 ppm), giving excellent signal dispersion and high spectral resolution . The synthesis and application of fluorine-containing compounds continue to increase in popularity, notably due to the use of such compounds as pharmaceuticals − and agrochemicals. , For structure elucidation, heteronuclear multidimensional NMR experiments using 1 H– 19 F correlations are available (e.g., hetero-COSY, − HETCOR, − HOESY, − and heteronuclear TOCSY), but these are time-consuming if high resolution is required in the indirect dimension. As an efficient alternative, the selective 1D FESTA (fluorine-edited selective TOCSY acquisition) methodology exploits the high spectral resolution of 19 F NMR to obtain clean 1 H NMR subspectra for individual spin systems involving different 19 F sites.…”

FESTA: An Efficient Nuclear Magnetic Resonance Approach for the Structural Analysis of Mixtures Containing Fluorinated Species

“…A well known and powerful NMR tool for structural studies is to use 1 H– 19 F correlation experiments (such as HETCOR, − hetero-COSY, − or HOESY − ), that provide NMR spectra containing valuable structural information. When working with small- and medium-sized molecules, the information extracted from these 1 H– 19 F correlations is rarely sufficient for determining the chemical structures, and knowledge of 1 H– 1 H correlations will still be needed.…”