Abstract: The invention is directed to a composition according to the following general formula: [(BL)-(M)-(Ar)-(X)]n+ (A)n-5 wherein M is a metal ion, BL is a bidentate ligand having two nitrogen atoms coordinating with a metal ion M, Ar is an, optionally substituted, conjugated cyclic hydrocarbon compound, X is H2O and A is an anion and n in n+ and n? are individually chosen from 1,2,3,4 or 5. The invention is also directed to its precursors and its use as multi-electron catalyst in a water splitting process.

Abstract: The invention concerns a two-dimensional heteronuclear correlation spectroscopy method for the measurement of solid state NMR samples. The nuclear spins are decoupled in the evolution interval by means of a FSLG-RF pulse sequence irradiated in the proton frequency band. Since this sequence may be very short compared to the ones hitherto used, and it is not necessary to irradiate simultaneously radio frequency in the area of the S-nuclei, the method is suitable in particular for high rotational velocities of the sample and high magnetic fields, where it effects a considerable improvement of the resolution.