The spectra were measured using an Agilent 400 MHz spectrometer. Samples were prepared by dissolving 130-150 mg in 1 ml of DMSO-d6. Dissolution lasted 24 h at room temperature using a Heidolph Multi Reax shaker set at 300 rpm. Calculations (Table ) were made on 13C NMR spectra with substracted Nuclear Overhauser Effect.