Electron nuclear double resonance complexes

Electron nuclear double resonance of transition metal complexes with organic ligands. A. Schweiger, Struct. Bonding (Berlin), 1982, 51, 1-119 (294). 

Schweiger A (1982) Electron Nuclear Double Resonance of Transition Metal Complexes with Organic Ligands. 51 1-122 Scozzafava A, see Bertini I (1982) 48 45-91... 

Electron Nuclear Double Resonance of Transition Metal Complexes with Organic Ligands... 

A prototypical example of a molecular probe used extensively to study the mineral adsorbent-solution interface is the ESR spin-probe, Cu2+ (Sposito, 1993), whose spectroscopic properties are sensitive to changes in coordination environment. Since water does not interfere significantly with Cu11 ESR spectra, they may be recorded in situ for colloidal suspensions. Detailed, molecular-level information about coordination and orientation of both inner- and outer-sphere Cu2+ surface complexes has resulted from ESR studies of both phyllosilicates and metal oxyhydroxides. In addition, ESR techniques have been combined with closely related spectroscopic methods, like electron-spin-echo envelope modulation (ESEEM) and electron-nuclear double resonance (ENDOR), to provide complementary information about transition metal ion behaviour at mineral surfaces (Sposito, 1993). The level of sophistication and sensitivity of these kinds of surface speciation studies is increasing continually, such that the heterogeneous colloidal particles in soils can be investigated ever more accurately. 

Although only one valence electron resides in a 5f-localized orbital on uranium in [U(C7H7)2], a formal oxidation state of -1-3 (5f ) was assigned, based on the fact that the HOMO Se molecular orbitals (occupied by four electrons) are nearly 50% 5f in character, and so two of these electrons were assigned to the metal. EPR and electron-nuclear double resonance (ENDOR) studies of [(C7H7)2U] suggest that the complex could be treated as 5f, with a ground-state molecular orbital comprised of both 5br and 5f(r orbitals. ... 

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