Multiplicity control in the polygeminal diazeniumdiolation of active hydrogen bearing carbons: Chemistry of a new type of trianionic molecular propeller

Over a century ago, Traube reported the reaction of four nitric oxides with acetone and sodium ethoxide to yield sodium methanebis(diazene-N-oxide-N'- hydroxylate) and sodium acetate. However, when this reaction is carried out in the presence of nitric oxide at slightly elevated pressures (35-40 psi) , a product corresponding to the addition of six nitric oxides, sodium meth anetris(diazene-N-oxide-N'-hydroxylate), forms as the main product in addit ion to a trace of the previously observed sodium methanebis(diazene-N-oxide -N'-hydroxylate) and sodium acetate. The corresponding potassium salts form when potassium hydroxide is employed as the base, while lithium hydroxide results in the formation of lithium methanebis(ldiazene-Noxide-Al'-hydroxyl ate) exclusively. Nitric oxide reacts with 3,3-dimethylbutan-2-one in the p resence of sodium and potassium hydroxide in methanol to yield sodium and p otassium 3,3-dimethylbutan-2-one-1,1,1-tris(diazene-N-oxide-N'-hydroxylate) , respectively. In contrast, the reaction in the presence of lithium hydrox ide forms lithium methanebis(diazene-N-oxide-N'-hydroxylate) and lithium pi valate. The differential reactivity of nitric. oxide with acetone and 3,3-d imethylbutan-2-one in the presence of the three bases is attributed to comp eting hydrolytic reactions of the acetyl and trimethylacetyl group-containi ng intermediates. A mechanism is proposed for the nitric oxide addition to active methyl groups in these reactions, where the product distribution bet ween the di- and trisubstituted methanes is under kinetic control of the co mpeting reactions. The products are characterized by NMR and IR spectroscop y, differential scanning calorimetry, and elemental analysis. Two different ially hydrated forms of potassium methanetris(diazene-N-oxide-N'-hydroxylat e) are characterized by single-crystal X-ray diffraction. From the metathes is reaction of the silver salt of methanetris(diazene-N-oxide-N'-hydroxylat e) with ammonium iodide, the corresponding ammonium salt is isolated in 59% yield, but only trace amounts of methylated products form in the reaction of the silver salt with methyl iodide. Density functional calculations (B3L YP/6-311++G**) are used to evaluate the bonding, ground-state structures, a nd energy landscape for the different conformers of methanetris(diazene-N-o xide-N'-hydroxylate)(3-) trianion, a new type of a molecular propeller, and its corresponding triprotonated acid.