6533b82cfe1ef96bd128f436

RESEARCH PRODUCT

“Through-space” nuclear spin–spin couplings in ferrocenyl polyphosphanes and diphosphino cavitands: A new way of gathering structural information in constrained P(III) ligands by NMR

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Abstract Nuclear magnetic resonance is an invaluable technique for investigating a variety of important issues ranging from the determination of molecular structure to therapeutic medical imaging. In this respect, the indirect nuclear spin–spin coupling involving common nuclei such as 1 H, 13 C or 31 P provides, via the J constant, conclusive data for compound characterization in solution. This electron-mediated nuclear spin coupling is usually regarded as being transmitted by covalently bonded magnetic atoms. However, several experimental and theoretical studies, first focused on constrained organofluorides, and more recently devoted to phosphane ligands highlighted the existence of very intense J -couplings operating “through-space”. Herein, the intramolecular “through-space” 31 P 31 P and 31 P 13 C couplings are discussed in the light of recent examples found in constrained phosphorus-containing ligands such as phosphinocalixarenes , phosphinocyclodextrins and ferrocenyl phosphanes . The emphasis is put on the origin and transmitting mode of these nonbonded spin–spin couplings as well as on the relevant structural information they provide in solution.