Chlorofluorieren mit Trifluormethylhypochlorit CF3OCl. Darstellung und spektroskopische Charakterisierung von Trifluormethyliodchloridfluorid CF3I(Cl)F

Chlorofluorinate with Trifluoromethylhypochlorite CF₃OCl. Preparation and Spectroscopic Characterization of Trifluormethyliodinechloridefluoride CF₃I(Cl)F The preparation of a new iodine(III) compound, trifluormethyliodinechloridefluoride CF₃I(Cl)F, via oxidative addition of trifluoromethylhypochlorite CF₃OCl to trifluoromethyliodide CF₃I is described. The thermolabile compound has been characterized by i.r., Raman, ¹⁹F NMR, and mass spectroscopy.     

Die NMR-Spektren von CF3I,CF3IF2 und CF3IF4

The NMR Spectra of CF₃I, CF₃IF₂, and CF₃IF₄ The ¹⁹F-NMR and ¹³C-NMR spectra of CF₃I, CF₃IF₂ and CF₃IF₄ were recorded in acetonitrile solution. The chemical shifts of the CF₃-groups are strongly dependent on the oxidation state of the iodine atom. With increasing oxidation state the resonances of the CF₃-groups in the ¹⁹F-NMR spectra are characteristically shifted to high field, whereas in the ¹³C-NMR spectra a characteristic shift to low field is measured. The absolute value of the coupling constants ¹J(¹⁹F? ¹³C) increases with increasing oxidation state from 344 Hz (CF₃I) via 354 Hz (CF₃IF₂) to 359 Hz (CF₃IF₄).     

The IR multiphoton decomposition of CF3I. The effect of inert and reactive gases

The multiphoton decomposition of CF₃I with a pulsed CO₂ laser has been studied at incident fluences of 0.6 and 1.2 J/cm². The effect of pressure on the reaction probability for dissociation of CF₃I was measured in the presence of added isobutane, Ar and CO₂. In the experiments with isobutane, the CF₃ radicals generated by the decomposition of excited CF₃I react to yield CF₃H in competition with the recombination to C₂F₆. The laser absorption cross section was also measured as a function of fluence at a pressure of 0.1 torr of CF₃I and with 0.5–2.0 torr of added isobutane. The experimental results were modeled with a master equation in order to obtain information on the energy transferred by collisions of excited CF₃I with the bath molecules. An energy dependent value of 〈ΔE〉_d produces the best fit to the experimental data. Integration of the rate equations to account for the fractional product yield, [CF₃I]/[C₂F₆], allowed for the calculation of the specific rate constant for hydrogen abstraction from isobutane by CF₃ radicals. The value obtained is dependent on the total pressure and higher than expected at room temperature. From these results, an effective temperature for the reaction mixture was calculated. © 1994 John Wiley & Sons, Inc.     

Vibrational relaxation and dissociation in the perfluoromethyl halides,CF3Cl,CF3Br,andCF3I

The processes of vibrational relaxation and unimolecular dissociation of the perfluoromethyl halides CF₃Cl, CF₃Br, and CF₃I have been studied in the shock tube with the laser-schlieren technique. Vibrational relaxation was resolved in pure CF₃Cl and CF₃Br (400–484 K and 400–500 K, respectively), and in the mixtures; 2% CF₃Cl/Kr (500–1000 K), 10% CF₃Cl/Kr (440–670 K), 4% CF₃Br/Kr (450–850 K), and 2% CF₃I/Kr (620–860 K). Relaxation in the pure gases is extremely rapid, but shows a well-resolved, accurately exponential decay which provides very precise relaxation times in close agreement with ultrasonic results. Relaxation times as short as 0.1 μs-atm can be resolved, showing the method has a resolution within a factor 2–3 of the best ultrasonic methods. Relaxation dilute in rare gas shows a complex double exponential behavior consistent with a two-stage series process. Rates of CF₃(SINGLEBOND)X fission in these mixtures were measured over 1800–3000 K, P<0.55 atm, for CF₃Cl; 1600–2500 K, P<0.55 atm, in CF₃Br; and 1260–2100 K, P<0.34 atm, in CF₃I. Rates for dissociation were derived from a full profile modeling using a secondary mechanism of six CF₃ reactions. RRKM analysis showed all dissociations to lie near the low pressure limit. Using literature barriers, these rates are best fit with (ΔE)_all=−270 cm⁻¹ for CF₃Cl, 〈ΔE〉_down=0.3 T for CF₃Br, and 〈ΔE〉_down=800 cm⁻¹ for CF₃F. All these transfers are on the large side, similar to those found in other halogenated methanes. © 1997 John Wiley & Sons, Inc.     

Reaktion von Chlornitrat mit CF3I: Isolierung von Trifluormethylchloriodnitrat CF3I(Cl)ONO2 und Kristallstruktur von Trifluormethylioddinitrat CF3I(ONO2)2

Reaction of Chlorine Nitrate with CF₃I: Isolation of Trifluormethylchloroiodinenitrate CF₃I(Cl)ONO₂ and the Crystal Structure of Trifluormethyliodinedinitrate CF₃I(ONO₂)₂ CF₃I reacts with ClONO₂ to Iodine(III)-compounds. After an addition CF₃I(Cl)ONO₂ is isolated and characterized by vibrational spectra. With surplus ClONO₂ it is formed CF₃I(ONO₂)₂. CF₃I(ONO₂)₂ crystallizes monoclinic in the space group P2₁/c with the cell parameters a = 1 024.3(6) pm, b = 873.5(6) pm, c = 873.4(6) pm and Z = 4. We measered following bonding distances: I? O: 207.3(3) and 220.8(2) pm, I? C: 221.1(4) pm and N? O: from 119.1(4) to 141.5(3) pm. Through an intermolecular I ··· O-contact the central iodine becomes a distorted plane geometry.     

Photolysis of CF3NO as a source of CF3 radicals,rate constant of the CF3 + CF3NO reaction at 296 K

The linear absorption cross-sections and photodissociation quantum yields for CF₃NO have been measured at the wavelengths 694.3 and 632.8 nm (ruby and He(SINGLEBOND)Ne lasers, respectively) in a wide range of total pressure at T = 296 K. The secondary reactions following the photolysis of CF₃NO have been studied. The rate constant of the CF₃ + CF₃NO reaction has been measured. The results obtained show CF₃NO photolysis be a convenient source of CF₃ radicals for kinetic studies. © 1996 John Wiley & Sons, Inc.     

Long path-FTIR studies of some atmospheric reactions involving CF3OO and CF3O radicals

In attempts to obtain kinetic and mechanistic data required for an assessment of atmospheric fate of alternative halocarbons containing a CF₃ group, reactions of the key free radical intermediates CF₃OO and CF₃O with several atmospheric compounds (i.e., NO, NO₂, alkanes and alkenes) have been studied at 297 ± 2 K in 700 torr of air. Experiments employed the long path-FTIR spectroscopic method for product analysis and the visible (400 nm) photolysis of CF₃NO → CF₃ + NO as a source for the precursor radical CF₃. Numerous labile and stable F-containing molecular products have been characterized based on kinetic and spectroscopic data obtained at sufficiently short photolysis time (≤1 min) to minimize heterogeneous decay on the reactor walls. Major new findings have been made for the reactions involving CF₃O radicals. The behavior of CF₃O radicals has been shown to be markedly different from that of CH₃O radicals, i.e., (1) O₂-reaction: no evidence for the F-atom transfer reaction CF₃O + O₂ → CF₂ O + FOO; (2) NO-reaction: addition reaction CH₃O + NO (+M) → CH₃ONO (+M), but F-transfer reaction CF₃O + NO → CF₂O + FNO; (3) NO₂-reaction: addition reaction for both radicals, but F-transfer reaction CF₃ + NO₂ → CF₂O + FNO₂ to a minor extent; (4) alkane-reaction: much faster H-abstraction by CF₃O, comparable to HO; (5) alkene-reaction: much faster addition reaction of CF₃O, comparable to HO. These results are summarized in this paper.     

Kinetic study of the reaction of chlorine atoms with CF3I and the reactions of CF3 radicals with O2, Cl2 and NO at 296 K

The kinetics of the gas-phase reaction of Cl atoms with CF₃I have been studied relative to the reaction of Cl atoms with CH₄ over the temperature range 271–363 K. Using k(Cl + CH₄) = 9.6 × 10^?12 exp(?2680/RT) cm³ molecule^?1 s^?1, we derive k(Cl + CF₃I) = 6.25 × 10^?11 exp(?2970/RT) in which E_a has units of cal mol^?1. CF₃ radicals are produced from the reaction of Cl with CF₃I in a yield which was indistinguishable from 100%. Other relative rate constant ratios measured at 296 K during these experiments were k(Cl + C₂F₅I)/k(Cl + CF₃I) = 11.0 ± 0.6 and k(Cl + C₂F₅I)/k(Cl + C₂H₅Cl) = 0.49 ± 0.02. The reaction of CF₃ radicals with Cl₂ was studied relative to that with O₂ at pressures from 4 to 700 torr of N₂ diluent. By using the published absolute rate constants for k(CF₃ + O₂) at 1–10 torr to calibrate the pressure dependence of these relative rate constants, values of the low- and high-pressure limiting rate constants have been determined at 296 K using a Troe expression: k₀(CF₃ + O₂) = (4.8 ± 1.2) × 10^?29 cm⁶ molecule^?2 s^?1; k_∞(CF₃ + O₂) = (3.95 ± 0.25) × 10^?12 cm³ molecule^?1 s^?1; F_c = 0.46. The value of the rate constant k(CF₃ + Cl₂) was determined to be (3.5 ± 0.4) × 10^?14 cm³ molecule^?1 s^?1 at 296 K. The reaction of Cl atoms with CF₃I is a convenient way to prepare CF₃ radicals for laboratory study. © 1995 John Wiley & Sons, Inc.     

Die reaktion von CF3CH2I mit (CH3)2Cd - ein beitrag zum reaktionsverhalten von polyfluoralkyliod-verbindungen mit metallorganischen verbindungen

CF₃CH₂I reacts with (CH₃)₂Cd in two steps by CF₃CH₂/CH₃exchange to yield CF₃CH₂CdCH₃ and (CF₃CH₂)₂Cd along with CH₃I. Although the previously unknown Cd-Compounds decompose readily in the course of the reaction and thus could not be isolated, they have been identified unambigously by ¹H, ¹⁹F-n.m.r.-spectroscopy. This reaction shows that the iodine in alkyliodine-compounds has to be strongly positively polarized to allow a reaction between alkyliodine- and dialkylcadmium- compounds.     

Diode laser spectroscopy of the 410 band of 12CF3I and 13CF3I in a supersonic jet

The diode laser absorption spectra of the 4¹₀ fundamental of ¹²CF₃I and ¹³CF₃I around the band centres at 1187 and 1154 cm⁻¹ respectively have been measured in a pulsed supersonic jet using both single orifices and linear arrays. Over 100 P, Q and R branch lines have been measured in ¹²CF₃I. Different mixtures of CF₃I and He were used to vary the rotational temperature to aid assignment. Least-squares fits yielded parameters in reasonable agreement with the results of Wahi, Job and Kartha [J. molec. Spectrosc. 114, 305 (1985)] who studied this band in a low pressure, cooled cell. A weaker absorption band appearing slightly blue shifted from the 4¹₀ band head is tentatively assigned to the 4¹₀6¹₁ hot band.     

The dark reactions F2 + CF3I,C2F5I,and n-C3F7I

The reactions between F₂ and the lowest members of the homologous series of perfluoroalkyl iodides (CF₃I, C₂F₅I, and n-C₃F₇I) have been studied. For these compounds, an exponential decrease in the alkyl iodide concentration over time following an induction period is observed for certain experimental conditions. Other conditions lead to chaotic-like kinetic behavior where the rate of alkyl iodide consumption continually changes. Kinetic rate data with CF₃I show that the disappearance rate depends upon both the type of surface and surface preparation. For all three compounds, Arrhenius plots reveal activation energies on the order of 10 kcal/mol, consistent with effective initiation steps of F₂ + RI → RIF + F, where R represents the CF₃, C₂F₅, or n-C₃F₇ radical respectively. The end products of the F₂ + RI reactions are RF, R₂, and IF₅, suggesting that the R radicals play an important kinetic role. Introducing O₂ into the F₂ + RI reaction systems results in successive oxidation of R by O₂, leading to the formation of CF₂O as an additional end product. IF(B → X) emission is observed from the RI-rich F₂ + RI reactions, confirming the existence of IF as an intermediate. © 1996 John Wiley & Sons, Inc.     

Koordinationsverbindungen des Silber(I) mit stickstoffhaltigen Liganden Kristallstruktur des NC?SCF2CF2S?CN

Coordination Compounds of Silver(I) with Nitrogen-Containing Ligands. Crystal Structure of NC? SCF₂CF₂S? CN The reaction of F₂S?NCN and NC? SCF₂CF₂S? CN with AgAsF₆ leads to the coordination compounds (F₂S?NCN)₂AgAsF₆ 2 and (NC? SCF₂CF₂S? CN)₂AgAsF₆ 5 . NC? SCF₂CF₂S? CN 3 is formed by the reaction of ClSCF₂CF₂SCl with HCN as well as with Me₃SiCN. 4 is a by-product of the reaction with HCN. 4 was characterized as a six-membered heterocycle. 3 was investigated by an X-ray single structure analysis. In the solid state the all-trans form was found.     

Mechanistic insights into the reaction of CF3CCl3 with SO3: Theory and experiment

Reaction mechanism of 1,1,1-trifluorotrichloroethane (CF₃CCl₃) and sulphur trioxide (SO₃) in the presence of mercury salts (Hg₂SO₄ and HgSO₄) was studied applying the density functional theory (DFT) at the UB3LYP/6-31+G(d,p) level. It was found that this reaction occurs in the free radical chain path as follows: mercury(I) sulphate free radical is generated by heat, causing CF₃CCl₃ to produce the CF₃CCl₂ free radical which reacts with SO₃ leading to the formation of CF₃CCl₂OSO₂ decomposing into CF₃COCl and SO₂Cl. The SO₂Cl free radical triggers CF₃CCl₃ to regenerate CF₃CCl₂ which recycles the free radical growth reaction. This elementary reaction has the highest energy barrier and it is therefore the rate control step of the whole reaction path. Experiment data can confirm the existence of the mercury(I) salt free radical and the free radical initiation stage. So, mercury salts play the role of initiators not that of catalysts. The results agree well with our hypothesis.     

Fundamental and overtone infrared spectra of CF3I

The i.r. spectra of CF₃I between 250 and 5000 cm⁻¹ have been measured with a resolution of 0.3–1 cm⁻¹ and with optical path lengths up to 4 bar·10 m. A few bands of a sample cooled down to 180 K and several bands of a sample enriched in ¹³CF₃I were also recorded. Values are assigned to most of the anharmonic x_ij and g_ii constants of ¹²CF₃I. Serious perturbations occur however by Fermi resonance between ν₁ and ν₂ + ν₃ and between ν₁ and 2ν₅, whose analysis is still very preliminary.     

ESR spectra and structure of the CF3Cl−, CF3Br−, and CF3I− radical anions

The anisotropic ESR spectra of the CF₃X^? radical anions (X = Cl, Br, I) have been observed following γ irradiation at 77 K of solid solutions containing up to 5 mole % of the CF₃X parent compound in tetramethylsilane (TMS), neopentane, and 2-methyltetrahydrofuran. The resolution of the line components in the TMS matrix allowed the spectra to be analyzed in detail, the parallel and perpendicular features showing clear evidence for axially symmetric hyperfine interactions with three equivalent fluorines and the unique halogen. On this basis, a matrix diagonalization program was used to calculate the line positions and the best-fit ESR parameters obtained. Confirmation of the CF₃X^? identification was achieved through chemical studies which showed that a similar ESR spectrum was generated by electron attachment to the parent molecule in a photoionization experiment. Also, the spectrum of the CF₃ radical was observed to grow in during the decay of the CF₃X^? spectrum in neopentane above 100 K. The spin density distributions calculated from the ESR parameters of these congeneric radical anions suggest that the unpaired electron resides in an a₁ (σ^*) antibonding orbital which is composed largely of the p orbitals from carbon and the unique halogen which lie along the C_3v symmetry axis of the radical anion. Consistent with this proposal, the spin densities in the s and p orbitals of the unique halogen increase along the series Cl, Br, I, which is the order expected for the effect of decreasing halogen electronegativity.     

Darstellung von Trifluormethylhalogen-Iodaten(I) des Typs (CH3)4N+CF3IX− (X = F,Cl, Br) und Trifluormethyltrifluormethoxyiodat(I) (CH3)4N+CF3IOCF3−

Preparation of Trifluormethylhalogen Iodate(I) Salts (CH₃)₄N⁺CF₃IX^? (X = F, Cl, Br) and Trifluormethyltrifluormethoxy Iodate(I) (CH₃)₄N⁺CF₃IOCF₃^? We describe the preparation of new trifluormethyliodate(I) salts CF₃IX^? (X = F, Cl, Br, OCF₃). (CH₃)₄N⁺CF₃ICl^? and (CH₃)₄N⁺CF₃IBr^? are obtained via addition of CF₃I with the corresponded tetramethylammonium halogenide. (CH₃)₄N⁺CF₃IOCF₃^? is synthesized by comproportionation of (CH₃)₄N⁺CF₃ICl^? with CF₃OCl under formation of Cl₂ at ?78°C. (CH₃)₄N⁺CF₃IF^? is formed either, through thermolysis of (CH₃)₄N⁺ CF₃IOCF₃^? under separation of COF₂, or reaction of CF₃I with (CH₃)₄N⁺ OCF₃^?. The thermolabile compounds have been characterized by i.r., Raman, ¹⁹F-, ¹³C NMR spectroscopy.     

New isomers of trifluoromethylated fullerene: C60(CF3)12 and C60(CF3)14

HPLC separation of the products of high-temperature reaction of a sublimed mixture of C₆₀–C₇₀ (10: 1) with CF₃I in a sealed ampoule allowed isolation and determination of molecular structures (X-ray crystallography and ¹⁹F NMR) of two new isomers of C₆₀(CF₃)₁₂ and one isomer of C₆₀(CF₃)₁₄. These isomers are characterized by low relative formation energies, which suggests that the trifluoromethylation process is basically under the thermodynamic control.     

Condensed‐Phase,Halogen‐Bonded CF3I and C2F5I Adducts for Perfluoroalkylation Reactions

A family of practical, liquid trifluoromethylation and pentafluoroethylation reagents is described. We show how halogen bonding can be used to obtain easily handled liquid reagents from gaseous CF₃I and CF₃CF₂I. The synthetic utility of the new reagents is exemplified by a novel direct arene trifluoromethylation reaction as well as adaptations of other perfluoroalkylation reactions.     

Condensed‐Phase,Halogen‐Bonded CF3I and C2F5I Adducts for Perfluoroalkylation Reactions

A family of practical, liquid trifluoromethylation and pentafluoroethylation reagents is described. We show how halogen bonding can be used to obtain easily handled liquid reagents from gaseous CF₃I and CF₃CF₂I. The synthetic utility of the new reagents is exemplified by a novel direct arene trifluoromethylation reaction as well as adaptations of other perfluoroalkylation reactions.     

Darstellung und charakterisierung von (CF3)2PPH2 und (CF3)2AsPH2

(CF₃)₂EPH₂ (E = P,As) may be prepared in high yield by the cleavage of M-P bonds in compounds of the type R₃MPH₂ (M = Si, Ge, Sn) with (CF₃)₂EX (X = Cl, Br, I). The direction of bond fission depends on X and on the reaction temperature. These new compounds may also be obtained, but in lower yield, by the reaction of LiAl(PH₂)₄ with (CF₃)₂EX. Application of the principle of this reaction to other R′₂EX compounds [(CH₃)₂PCl, (CH₃)₂AsI, F₂PX (X = Br, I)] has been investigated. The IR and NMR spectra of the new compounds are reported.