Inis C. Tornieporth-Oetting

Reaction of hydrazinium azide with sulfuric acid: The X-ray structure of [N2H6][SO4]

Abstract Stoichiometric reaction of [N2H5][N3] with 1 equiv. of H2SO4 in water led to the quantitative formation of pure hydrazinium(+2) sulfate and hydrazoic acid. The reaction was followed by means of 14N NMR spectroscopy and the 14N NMR spectra of [N2H5][N3] and HN3 are reported. The structure of [N2H6][SO4] was determined at −100°C. The sulphate anion has the configuration of an almost regular tetrahedron, while the hydrazinium cation may be considered to be of the trans type. There are no hydrogen bonds between the oxygen atoms, however, very short O···N distances in the range between 2.7 and 2.9 A can be interpreted as strong hydrogen bonds between the cations and the anions.

Recent Developments in the Chemistry of Binary Nitrogen-Halogen Species

Abstract The chemistry of the most recent years of binary nitrogen-halogen species is discussed in four chapters. Chapter I focusses on nitrogen-fluorine compounds, including NF3 N2F4 N2F2 and the NF4 + N2F3 + N2F+ and NF2+ cations. In Chapter II the trihalogeno nitrides NX3 (X = Cl, Br, I) and the NCl4 + cation are described and the likely existence of heavier analogues NBr4 + and NI4 + is discussed. Whereas all halogen azides XN3 (X = F, Cl, Br, I) are summarized in Chapter III, the ionic nitrogen iodine species I2N2 + I(N3)2 + I2N3 − and I(N3)2 − are comprised in Chapter IV.

Reactivity of Lewis acids towards nitriles; crystal structure and electron deformation density of C2N2·SbF5 and photoelectron spectrum of AsF5

The reactivity of nitriles and dinitriles HCN, C2N2, CCl2(CN)2 and CH2(CN)2 towards AsF5 and SbF5 has been investigated. The new compounds HCN·AsF51, HCN·SbF52, C2N2·AsF53, C2N2·SbF54, CH2(CN)2·AsF55, CH2(CN)2·(2AsF5)6 and CCl2(CN)2·AsF57 have been characterized by chemical analysis, IR, Raman, 1H, 19F and 14N NMR spectroscopy. The crystal structure of the first example of a cyanogen adduct C2N2·SbF54 has been determined. Compound 4 crystallizes in the orthorhombic space group C2221 with cell parameters a= 6.579(1), b= 16.245(1) and c= 6.389(1)A. The deformation density of the molecule was examined. The reactivities of HCN and C2N2 towards the strong Lewis acid AsF5 are discussed on the basis of the hard–soft acid–base principle. The hitherto unknown ionization potential of AsF5(15.57 eV) was obtained by photoelectron spectroscopy. A semiquantitative molecular orbital scheme for AsF5 is presented.

Covalent Inorganic Nonmetal Azides

Inorganic azides can be classified into (i) ionic salts (e.g., NaN3), (ii) heavymetal azides (e.g., AgN3, PbN3), and (iii) covalently bound nonmetal azides (XN3: X = H, R2B, R3Si, NO, NO2, R2P, halogen; R = alkyl, aryl) (Jones, 1973). Whereas the ionic salts are reasonably stable materials and sodium azide is prepared on a commercial scale, the major use of the heavy-metal azides depends on their explosive nature (Greenwood and Earnshaw, 1984). Particularly, lead azide is used for detonators because of its reliability under a variety of adverse, especially damp conditions (Kohler and Meyer, 1991). Although the covalent azides have been known since the beginning of this century, it is only in recent years that these azides have found use in preparative chemistry and that their structures have been elucidated (Tornieporth-Oetting and Klapotke, 1993a). The characterization and usage of the covalent nonmetal azides have obviously been hampered by their thermodynamic and kinetic instability. HN3 and all of the halogen azides are very hazardous. Especially dangerous are the pure halogen azides in the condensed phase (Dehnicke, 1983). Violent explosions can also occur in the gaseous state upon sudden variations of the pressure (Dehnicke, 1983).

The preparation and structure of (SeCl2)2N+AsF6–·MeCN containing the first ternary selenium, nitrogen, chlorine cation

The Cl2Se–N–SeCl2+ cation which represents the first example of a ternary Se, N, Cl species has been prepared by the reaction of SeCl3+AsF6– and N(SiMe3)3; the crystal structure of the AsF6– salt has been determined by a low-temperature single crystal X-ray diffraction study.

Preparation of N(SeCl)2+X–(X = SbCl6or FeCl4), F3CCSeNSeCCF3+SbCl6–, F3CCSeNSeCCF3, F3CCSeNSeCCF3and F3CCSeSeC(CF3)C(CF3)SeSeCCF3. Electron diffraction study of F3CCSeSeCCF3and crystal structure of the eight-membered heterocycle F3CCSeSeC(CF3)C(CF3)SeSeCCF3

The salts N(SeCl)2+SbCl6–1 and N(SeCl)2+FeCl4–2 were synthesized by reaction of SeCl3+ X–(X = SbCl6 or FeCl) with N(SiMe3)3; 1 was also formed by reaction of Se2NCl3 with SbCl5. Reaction of 1 with SnCl2 and F3CCCCF3 led to the formation of F3C[graphic omitted]CF3+ SbCl6–3. In this reaction the Se2N + cation is a likely intermediate because SnCl2 seems to be essential for chloride abstraction in the first reaction step to generate Se2N+in situ which then adds F3CCCCF3 to yield 3. Compound 3 is a useful building block to generate selenium compounds such as F3C[graphic omitted]CF34, F3C[graphic omitted]CF35 and F3C[graphic omitted]CF36. The heterocycle 5 was shown by electron diffraction to have an approximately planar four-membered ring structure. The structure of compound 6 was determined by X-ray crystallography: orthorhombic, space group Pbca, a= 10.1920(21), b= 13.0615(20) and c= 22.050(5)A. In order to rationalize the structures of 5 and the cation F3C[graphic omitted]CF3+, ab initio calculations were made on model compounds in which the CF3 groups were replaced by a fluorine atom (i.e.F[graphic omitted]F for 5and F[graphic omitted]F+ for the cation in 3). In addition, mass spectrometric experiments were performed in order to examine the structures and stabilities of the unligated cation F3C[graphic omitted]CF3+ as well as its neutral counterpart. The existence of the neutral radical 4 was established by means of neutralization–reionization mass spectrometry.

Uranium hexafluoride: laboratory scale synthesis, coordination behaviour towards nitriles and Raman spectra

Abstract The synthesis of uranium hexafluoride, UF6, using uranium metal and chlorine trifluoride is described. The method is suitable for laboratory scale (10–20 g) preparation of pure UF6. Raman spectra of pure UF6 have been observed for the solid state and for the first time in cyanogen chloride solution. The coordination behaviour of UF6 towards Lewis bases like cyanogen chloride (ClCN), cyanogen ((CN)2), hydrogen cyanide (HCN) and malononitrile (CH2(CN)2) was investigated.

1,3,5-Triazine adducts with AsF5. Crystal structure of (HCN)3·AsF5

1,3,5-Triazine was treated with AsF5 in different stoichiometries to yield the adduct complexes (HCN)3·nAsF51–3(n= 1–3), the latter of which (3) is stable in solution only. The monoadduct (HCN)3·AsF5 crystallizes in the orthorhombic space group Pcab with cell parameters a= 10.584(13), b= 12.965(11) and c= 10.369(5)A. The crystal data were collected at 100 K and the final refinement values are R= 0.051 and R′= 0.071. All compounds have been characterized by chemical analyses, vibrational spectrometry (IR and Raman) and 1H, 13C and 14N NMR spectroscopy. The thermodynamics of the adduct formation between (HCN)3 and AsF5 are discussed on the basis of the extended hard-soft acid-base principle.

Preparation of AsF4+PtF6– containing the tetrafluoroarsenic(V) cation

The AsF4+ cation which represent the last missing member in the series of the tetrahalogenoarsenic(V) cations has been prepared by the reaction of Pt, AsF5 and F2 under electrical resistance heating of the platinum wire.

Synthesis and characterization of novel halogeno(+I) adduct complexes containing malononitrile and 1,3,5-triazine

Abstract The 1-halogeno-1,3,5-triazinium hexafluoroarsenate and hexafluoroantimonate compounds of the type [(HCN)3X][MF6] (MAs; XF, (1), Cl (2) and MSb; XBr (3)) have been synthesized by direct reaction of 1,3,5-triazine, (HCN)3, with halogenomonofluorides, XF, in the presence of AsF5 or SbF5, respectively. The reactions of (HCN)3 and malonitrile, CH2(CN)2, with [I3][AsF6 afforded the iodonium adduct species [{(HCN)3}nI][AsF6] (n=1 (4), 2 (5)) and [{CH2(CN)2}nI][AsF6] (n=1 (6), 2 (7)). All compounds have been characterized by chemical analyses, proton NMR spectroscopy and vibrational spectral data (IR, Raman). Temperature dependent 1H NMR spectroscopy on SO2 solutions of 1–3 revealed functional behaviour at room temperature which was frozen down at −60 °C (two resonances, ratio 1:2). According to the NMR the scale the cations in 4 and 5 exist already in the slow exchange region at room temperature. Solution behaviour, IR and UV data of 6 (naples yellow reddish) and 7 (black) suggest 7 to be polymeric and 6 to be monomeric with strong intermolecular I···I interactions.