Abstract: Novel compounds capable of carrying and releasing nitrogen oxide (NO) in a biological medium, their use for implementing a therapeutic treatment method or a diagnostic method applied to a human or animal body, and for making medicines useful for treating or preventing disorders affecting the human or animal cardiovascular, nervous, immune, renal or pulmonary system, specifically, an organometallic complex of nitrogen oxide, wherein the cationic part is of the formula (I) in which x=0 or 1; x′=2 or 3; y=0, 2 or 3; z=0 or 1; with the condition that, if y=0 (or z=0) then z=0 (or y=0; respectively); R is a group chosen from the group formed by: a hydrogen atom, —(CH2)2COOH and R1, R2, R3 and R4 are groups chosen from the group formed by: a hydrogen atom and alkyl groups comprising from 1 to 4 carbon atoms; and M2+ is a divalent cation Fe++ or Co++.

Abstract: Process for preparing hydrogen peroxide, comprising the following steps: a) a step of reduction of dioxygen in acidic medium with a hydrophobic organometallic complex, and b) a step of separation of the oxidized organometallic complex resulting from step a) and of the hydrogen peroxide by liquid/liquid extraction.