Addition Of Cl2 Research Articles

Some reactions of transition metal complexes containing unsaturated ligands with M-C(sp) or M-C(sp2) bonds

Abstract

Synthetic and Structural Studies of Precursors to Polymers Containing AN -(R)CNSN- Backbone

Abstract The ring systems (Me2NCN)x(NSCl)2 (x=1 or 2) are prepared by (a) the reaction of dimethylcyanamide with (NSCl)3 in CCl4 at 60[ddot]C and (b) the oxidative addition of Cl2 to 1,5-Me2NC(NSN)2CNMe2. Treatment of (Me2NCN)(NSCl)2 with Me3SiNSNSiMe3 or Me3SiNSO produces the bicyclic compound Me2NCS3N5. The latter reagent also yields 1,5-Me2NC(NSN)2SCl shown by X-ray crystallography to be a folded eight-membered ring. The dications (Me2NCN)x(SN)2 2+ (x=1 or 2) are readily obtained from (Me2NCN)x(NSCl)2 and SbCl5. The reduction of (Me2NCN) (NSCl)2 with azide ion is briefly described.

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R2PN)(SN)2 (R = Me, Ph, F)

The oxidative addition of Cl2 (using SO2Cl2) to the six-membered ring (R2PN)(SN)2 (R = Me, Ph) produces the mixed phosphazene–thiazyl heterocycles, (R2PN)(NSCl)2, which react with Me3SiNSNSiMe3 to give the bicyclic compounds R2PS3N5. The latter undergo thermal decomposition, at ca. 100 °C in toluene, via reductive elimination of an NSN unit to regenerate (R2PN)(SN)2 in high yield. Kinetic measurements of this process, using 31P nmr spectroscopy, yield an activation energy of 102.4 ± 6.0 kJ mol−1 for the release of the NSN fragment from Me2PS3N5. The thermolysis route has been used to prepare the thermally unstable (F2PN)(SN)2, characterized as a 1:1 adduct with norbornadiene.

Radiative lifetime and collisional quenching of carbon monochloride (A 2Δ) in an alternating current glow discharge

Glow discharges are widely employed in semiconductor processing but are relatively poorly understood owing to, in part, a lack of reliable, quantitative diagnostics. Laser-induced fluorescence promises to be a useful in situ, nonintrusive probe for species concentrations and gas-phase temperatures, but requires the determination of fluoresence yields (i.e., radiative vs nonradiative decay rates) as a function of the plasma state and molecular rotational quantum number. In this work, carbon tetrachloride plasmas, which are used in the dry etching of such materials as Al, Si, GaAs, and InP, are examined using the laser-induced fluorescence technique. The quantum yield φ of CCl A 2Δ→X 2Π fluorescence is determined as a function of pressure, flow-rate, power, electrode temperature, and feedstock composition. Total pressure and addition of Cl2 to the feedstock are found to be most important in reducing the quantum yield; other plasma parameters and addition of O2, He, Ar, or N2 are found to be of secondary importance. The radiative lifetime of carbon monochloride CCl, A2Δ (v=0) is found to be 105±3 ns and to be independent of rotational quantum number up to J=45.5. The weak dependence of CCl laser-induced fluorescence on most plasma variables makes it nearly ideal as a simple, direct, and quantitative temperature and concentration diagnostic.

Sulfur-tetrafluoride-imides and pentafluorosulfanyl-derivatives

Abstract Pentafluorosulfanyl-derivatives are obtained by the addition of Cl2 or chlorides to the NS-triple bond of NSF3 in the presence of HgF2 : (In the same way perfluoroalkyl-dichloro-amines were prepared from nitriles; e.g. From the reaction of NSF3 with ClF, besides SF5NCl2 [1], the cyclic sulfurtetrafluorideimide (ClNSF4)2 is isolated [2]. From NSF3 and F2 pentafluorosulfanyl-sulfurtetrafluorideimide is formed NSF3 exc. + F2 → SF5  NSF4 (23 %) , the key substance to bis(pentafluorosulfanyl)amines. The properties of these compounds will be dlscussed in detail.

Evidence for Thermal Hydrogen-Atom Reactions in Irradiated Gaseous HCl

The addition of SF6, which is known to have a high cross section for reaction with thermal electrons, reduces the hydrogen yield from irradiated gaseous HCl to G(H2) = 3.9. The yield of hydrogen from pure HCl is G(H2) = 8.0 and the reduction of 4.1 G units achieved by the SF6 is within experimental error equal to Gionization for the system. Both Cl2 and Br2 cause a greater reduction to a residual or ``unscavengable'' hydrogen yield, GH″, of 2.2±0.2 G units. In the case of Cl2 this value is within experimental error independent of temperature over the range −79° to 23°C. The addition of Cl2 to SF6—HCl mixtures of a composition such that virtually all electrons are scavenged by SF6 causes a reduction from the SF6 plateau to the same residual yield observed with Cl2 and Br2 alone. This reduction may be attributed to a competition between Cl2 and HCl for thermal H atoms, which are formed in processes not involving thermal electrons as direct precursors. A competition kinetic study gave the following values of kH+HCl/kH+Cl2: 8.7±0.5×10−3 at 23°C; 7.5±0.5×10−3 at 1°C; and 1.6±0.5×10−3 at −77°C. The values at 23° and 1°C are in good agreement with recent experimental values of this ratio obtained by other methods. Possible origins of the thermal hydrogen atoms and the residual hydrogen yield are discussed.