Through-space coupling interactions
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The square-planar complexes [MR2L2] (M = Pd, Pt; R = 3,5-C6Cl2F3) [L2 = OPPyPh2 (Py = 2-pyridyl); SPPyPh2; OPPy2Ph; DMBI (3,3′-dimethyl-2,2′-biindazole); OPPyPh(NHTol-p); p-TolNPPy2Ph] have been prepared by treating cis-[MR2(THF)2] (THF = tetrahydrofuran) with the appropriate chelate ligands. The 19F-NMR spectra of these complexes show the presence of intramolecular through-space F-F couplings between ortho-fluorine atoms of nonequivalent R groups, which provide information for the assignment of the different ortho-fluorine signals and can be used to study the dynamic behavior of the mentioned complexes such as: a) Rotation of the R group in either Pd or Pt complexes, at the same or at different rates for each R groups depending on the neutral ligand; and b) exchange of the coordination sites of the chelating ligand, either by Berry or by turnstile mechanisms. The activation parameters for some of the processes are given.
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