Ammonolytic Processes in Liquid Ammonia

Abstract

Reaction of WBrs and BrN3 afford the highly explosive compound WBrgN3 (symmetry class C4,), soluble in CC14:An analogous reaction occurs with UCls and CIN3, affording an azide chloride, probably UC15N3, which loses N2 and CI2 in boiling CC14 and thus yields polymeric UNCI3.ClN3 or BrN3 react with the metal carbonyls Fe(C0)5, Mo(CO)~, and W(CO)6 with formation of well-defined car-bony1 azide halides M(CO)zN3X (X = C1 or Br). Their infrared spectra and magnetic behavior indicate that a substantially planar four-membered ring occurs in these iron compounds, the halide being ionic:These compounds show the paramagnetism of the unperturbed Fez' ion (p = 5.29 B.M., 0 = 0 OK) and are the first examples of paramagnetic iron-carbonyl compounds. The Fe-C linkage appears to be a pure o-bond without backdonation. On thermal decomposition at 9OoC in a vacuum the CO-free azide halides FcCIN3 and FeBrN3 (p = 4.80 B.M., 0 = 12°K) are formed. The carbonyl azides and the simple azide halides of FeII are not explosive; this is attributed to locking of the lone electron pair on the cc-Natom.The carbonyl azide halides of Mo and W, M(CO)zCIN3, are polymeric (n = 6), both CI and N3 acting as bridges. Intense metal-metal interaction results, as shown by the magnetic behavior: xrn = -74.9 x 10-6 EMU/mole. CIN3 reacts with organometallic compounds such as Cd(CH3)z and [Al(C2H5)3]2 with partial replacement of alkyl by azide: M O ( C O )~C I N~: = 0.93 B.M., 0 = -20°K; W(C0)2CIN3:Azidomethylcadmium forms colorless crystals that do not melt and for which infrared spectra indicate an ionic structure: [CdCH3]0Nje. Azidodiethylaluminum is a colorless distillable liquid (b.p. 63 "C/IO-3 mm Hg), which dimerizes through the azide group; its infrared spectrum indicates a strictly planar four-membered Al-N ring.Addition of dialkylaluminum hydrides to molecules with C = C double bonds in side chains or at chain ends, and treatment of the products with transition-metal halides (e.g. TiC14), afford macromolecular Ziegler catalysts that initiate graft and block polymerization of ethylene and cc-alkenes. Graft polymers with stereoregular poly-cc-alkene side chains become accessible in this way.Macromolecules containing RC=NM linkages are formed on addition of organometallic compounds of lithium (LiR) or magnesium (MgRHal) to the N = C triple bond in styieneacrylonitrile copolymers, and they initiate anionic graft polymerization ofacrylonitrile(AN), methyl methacrylate (MMA), 2-vinylpyridine (2-VP), and 4-vinylpyridine (4-VP).Reaction with Na of macromolecules containing O=C, N =C, or C=C linkages i n side chains gives macromolecular radical anions (e.g. high-polymeric ketyls in the case of poly-pvinylbenzophenone) or dianions, formed by electron-transfer from the metal to the multiple bond. Both the radical anions and the dianions initiate anionic graft polymerization of AN, MMA, 2-VP, 4-VP, butadiene, and styrene, and in this way pure graft copolymers arc formed, free from "backbone molecules" and from homopolymers of the grafted monomer.Pure graft copol...