Abstract
The solid state and solution NMR spectra of the tetrakis(pyrazol-l-yl) borate (La) and tris(3,5-dimethylpyrazol-l-yl) hydroborate (Lb) ligands and their complexes with MeHgII and RSHgII (R = Me, Et) are reported. The solid state 13C and 15N solid state NMR spectra of the MeHgLa complex are consistent with the reported X-ray structure. The close similarity of the spectral data shown by MeHgLa and MeSHgLa suggests that the two species have the same structure. In order to confirm this hypothesis, the structure of MeSHgLa has been determined by single crystal X-ray diffraction. The chemical shift anisotropy (CSA) of 199Hg resonance is too large in these T-shaped complexes and does not allow the observation of the 199Hg resonance under cross polarisation-magic angle spinning (CPMAS) experimental mode. On the other hand 199Hg CPMAS NMR spectra were obtained for the complexes with the Lb ligand. The reduced 199Hg CSA value together with the information gained from the 13C and 15N CPMAS NMR spectra suggest a tetra coordination around mercury in these complexes. The tight co-ordination mode shown by complexes with the Lb ligand is reflected in a decrease in the thiol intermolecular exchange rate in solution. This decreased ligand lability allows the detection of 3JHg-H couplings (inside HgSCH3 and HgSCH2CH3 moieties) in the low temperature NMR limiting spectra.
Lingua originale | Inglese |
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pagine (da-a) | 2695-2702 |
Numero di pagine | 8 |
Rivista | Polyhedron |
Volume | 13 |
Numero di pubblicazione | 18 |
DOI | |
Stato di pubblicazione | Pubblicato - 1994 |
Pubblicato esternamente | Sì |