Abstract: The present invention relates to a dinitroxide biradical compound of general formula (I): In formula (I), A is a carbon, an ammonium, or a phosphonium; each of A1 to A6 is a single bond, O, N, N(O), S, S(O), SO2, C(O), or a (C1-C4) alkyl chain; and Z1 and Z2 are selected from R1 and R2 in combination, so that there is always at least one R2 group that is substituted with R3 group. In Z1 and Z2, R1 is an H, an aryl, or a heteroaryl; R2 is an alkyl chain, an alkenyl chain, an alkynyl chain, a cycloalkyl, a heterocycloalkyl, an aryl, or a heteroaryl; and R3 is an alkyl chain, an alkenyl chain, an alkynyl chain, a cycloalkyl, a heterocycloalkyl, an aryl, a heteroaryl, an ether, an ester, or an azide. When Z1 and Z2 are combined together with the same carbon atom of the nitroxide ring to which they are bonded, they form a spirocycloalkyl or a spiroheterocycloalkyl, the spirocycloalkyl or the spiroheterocycloalkyl being substituted with R3.

Abstract: Non aqueous solvents or mixtures for DNP NMR spectroscopy, method to prepare said solvents or mixtures and use of said solvents or mixtures The present invention concerns a method to determine the efficiency of a solvent to impregnate a sample material for use in a dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) experiments, characterized in that the method comprising: —selecting a non-aqueous solvent, —providing a polarizing agent that is soluble in the non-aqueous solvent, —dissolving the polarizing agent in the non-aqueous solvent, —impregnating or dissolving the sample material with the non-aqueous solvent containing the polarizing agent, —performing a solid state DNP NMR experiment on the impregnated sample material, —determining a DNP enhancement factor of the DNP NMR experiment.

Abstract: The invention concerns a dinitroxide biradical compound, in which the two nitroxide units are held by a rigid linkage, of general formula (I) in which—A is a carbon, an ammonium or a phosphonium, each of A1 to A6 is selected separately from the group comprising a single bond, O, N, N(O), S, S(O), SO2, C(O), a (C1-C4) alkyl chain, Z1 and Z2 are chosen from RI and R2 in combination, such that there is always, in the combination, at least one R2 group that needs to be substituted by an R3 group, RI is an H, a (C6-C18) aryl or a (C3-C18) heteroaryl, R2 a (C1-C17) alkyl chain, a (C1-C17) alkenyl chain, a (C1-C17) alkynyl chain, a (C4-C17) cycloalkyl, a (C4-C17) heterocycloalkyl, a (C6-C18) aryl, a (C3-C18) heteroaryl, R3 is a (C1-C17) alkyl chain, a (C1-C17) alkenyl chain, a (C1-C17) alkynyl chain, a (C4-C17) cycloalkyl, a (C4-C17) heterocycloalkyl, a (C6-C18) aryl, a (C3-C18) heteroaryl, an ether —OR, an ester —C(O)O—R (in which R is any hydrocarbon radical), an azide, and in which, when Z1 and Z2 are combined to