Vibronic spectra and S1 excited electronic state molecular structures for acetyl chloride and acetyl fluoride

Vapor-state absorption spectra have been recorded for acetyl fluoride and acetyl chloride and also for deuterated derivatives with path lengths up to 40 m. The origins of the S₁S₀ transitions have been derived, together with the torsional-vibration energy levels in the ground state S₀ and excited singlet state S₁. Fitting the calculated and observed rotational contours of the vibronic bands has been used to estimate the geometrical parameters in the S₁ states. The carbonyl groups in the S₁ states are nonplanar. The internal-rotation potentials have been determined for acetyl fluoride and acetyl chloride in the S₁ and S₀ states. The relative intensities of the torsional transitions in those states indicate that the minima in the potential energy are appreciably displaced along the torsional coordinate in the S₀ and S₁ states.Chemical Faculty, Lomonosov Moscow University. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 1, pp. 26–30, January–February, 1993.     

Molecular structures of acetyl fluoride and acetyl iodide

The molecular structures of acetyl fluoride and acetyl iodide have been determined by making use of the average distances obtained in the present study together with the moments of inertia reported in the literature. The large amplitude theory for a molecule with an internal top was used in the joint analysis. The thermal-average values of internuclear distances r_g and the bond angles in the zero-point average structure Φ_z are as follows: r_g(C-O) = 1.185 ±0.002 $\text{}\text{?}$rA, r_g(C-F) = 1.362± 0.002 Å, r_g(C-C) = 1.505±0.002 Å, r_g(C-H) = 1.101 ±0.004 Å, Φ_z(OCF) = 120.7°±0.4°,Φ_z(CCF) = 110.5° ± 0.5°, Φ_z(HCH) = 109.3°±0.6° tilt(CH₃) = 0.1°±1°, for acetyl fluoride; r_g(C=O) = 1.198±0.013 $\text{}\text{?}$rA, r_g(C-I) = 2.217±0.009 Å, r_g(C-C) = 1.492±0.015 $\text{}\text{?}$rA, r_g(C-H) = 1.101 ± 0.004 Å, Φ_z(OCI) = 119.5°± 0.8°,Φ_z(CCI) = 111.7°±0.9°, Φ_z(HCH) = 110.8°±0.8° and tilt(CH₃) = 1.7°+5.4° for acetyl iodide. The uncertainties represent the estimated limits of error. The barriers V₃ to internal rotation have been reanalyzed making use of the effective moments of inertia of the methyl top estimated on the basis of the large amplitude theory and resulted in 1039 and 1176 cal mol^?1 for acetyl fluoride and acetyl iodide, respectively. The structure parameters have been compared with those of other CH₃COX (X = Cl, Br, H, CH₃) type molecules.     

Reaction of acetyl bromide with triphenylarsine oxide

Conclusions Triphenylarsine dibromide and acetic anhydride are formed when acetyl bromide and triphenylarsine oxide, taken in a 21 molar ratio, are reacted in anhydrous toluene.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 168–169, January, 1971.     

Synthesis and crystal structures of (2.2.2-cryptand)rubidium chloride and bromide hydrates

Two complexes, (2.2.2-cryptand)rubidium chloride and bromide hydrates [Rb(Crypt-222]Hal · 3.5H₂O (Hal = Cl (I) and Br (II)), are synthesized. The structures of isomorphic crystals of compounds I and II are studied by X-ray diffraction analysis. The crystals are trigonal: space group P \(\overline 3 \), Z = 2; I: a = 11.810 Å, c = 11.302 Å; II: a = 11.890 Å, c = 11.402 Å. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.060 (I) and 0.077 (II) for 2650 (I) and 2700 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). In crystals of complexes I and II, the [Rb(Crypt-222)]⁺ cation of the host-guest type lies on the crystallographic axis 3 and has the approximate symmetry D ₃. In complexes I and II, the coordination polyhedron of the Rb⁺ cation is a two-base-centered trigonal prism somewhat distorted to an antiprism. The crystals of compounds I and II contain H-bonded disordered cubes of the water molecules and Cl^? or Br^? anions.     

Cleavage ofβ -propiothiolactones with methanesulfenyl chloride and acetyl sulfur chloride

-Propiothiolactones are cleaved at the S-CO bond by methanesulfenyl chloride and acetyl sulfur chloride to form mixed disulfides — derivatives of the acid chlorides of -mercapto-isobutyric acid. The mixed disulfides readily disproportionate on heating under acid or base catalysis conditions to give the corresponding symmetrical disulfides. A convenient method was found for obtaining the previously hard-to-obtain symmetrical disulfides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 475–478, April, 1972.     

On the reaction of acetyl bromide with phenyldi-n-alkylarsine sulfides

Conclusions Reaction of acetyl bromide with phenyldi-n-alkylarsine sulfides in a sealed tube at 80–90° for 14–18 h gave alkyl bromide, the mixed thioanhydride of phenyl-n-alkylarsinic acid and acetic acid, phenyl-n-alkylbromoarsine and the S-alkyl ester of thioacetic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1878–1880, August, 1968.     

Reaction of acetyl chloride with triphenylarsine oxide

Conclusions The reaction of acetyl chloride with triphenylarsine oxide (21 molar ratio) in anhydrous toluene leads to formation of triphenylarsine dichloride and acetic anhydride.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1432–1434, June, 1970.     

Gas-phase structures of acetyl peroxynitrate and trifluoroacetyl peroxynitrate

The molecular structures and conformational properties of acetyl peroxynitrate (PAN, CH3C(O)OONO2) and trifluoroacetyl peroxynitrate (FPAN, CF3C(O)OONO2) were investigated in the gas phase by electron diffraction (GED), microwave spectroscopy (MW), and quantum chemical methods (HF/3-21G, HF/6-31G*, MP2/6-31G*, B3PW91/6-31G*, and B3PW91/6-311+G*). All experimental and theoretical methods show the syn conformer (C=O bond of acetyl group syn to O-O bond) to be strongly predominant relative to the anti conformer. The O-NO2 bonds are extremely long, 1.492(7) A in PAN and 1.526(10) A in FPAN, which correlates with their low bond energy and the easy formation of CX3C(O)OO* and *NO2 radicals in the atmosphere. The O-O bonds (1.418(12) A in PAN and 1.408(8) A in FPAN) are shorter than that in hydrogen peroxide (1.464 A). In both compounds the C-O-O-N dihedral angle is close to 85 degrees.     

The reaction of acetyl chloride with phenyldialkylarsine sulfides

Conclusions The reaction of acetyl chloride and phenyldi-n-alkylarsine Sulfides on heating in sealed tubes at 80–90° C forms phenyl-n-alkylchloroarsines and S-alkyl esters of thioacetic acid.Translated from Izvesitya Akademii Nauk SSSR, Seriya Khimicheskiya, No. 2, pp. 413–414 (1968).     

Some reactions of dialkyltin oxides with acetyl chloride and trimethylchlorosilane

Dialkyltin oxides react with acetyl chloride to give R₂ SnClOAc or R₂SnCl₂, depending on the stoichiometry, and with Me₃ SiCl to give (ClR₂ Sn)₂ O.     

Reactions of 1,4-dioxa-2-silacyclohexanes with acetyl chloride

The reactions of 1,4-dioxa-2-silacyclohexanes with acetyl chloride lead to the cleavage of the Si−O bond to form chlorotriorganosilanes containing the acetoxy group in the organic radical at the silicon atom. Hydrolysis of these chlorosilanes affords bis(acetoxy-alkoxy(aryloxy)methyl)disiloxanes, while the reactions with cage copper sodium phenylsiloxane give dodecaphenyl[dodeca(acetoxyorganodimethylsilyloxy)]cyclododecasiloxanes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2527–2529, December, 1998.     

Potentiometric determination of chloride and bromide in airborne dust

Summary A simple, rapid and reproducible potentiometric titration method for determination of both bromide and chloride in airborne dust is described. The use of a precise microburette and a differentiating recorder allows good resolution of the two species determined. The method can be easily applied for routine environmental control analysis.

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Zusammenfassung Die Anwendung eines einfachen, schnellen und reproduzierbaren potentiometrischen Verfahrens zur Bestimmung von Bromiden und Chloriden in Stauben wurde beschrieben. Der Einsatz einer Motorkolbenbürette für die relativpotentiometrische Titration und die Verwendung eines Differentiators erlauben eine exakte Bestimmung des Titrationsendpunktes und ermöglichen so das gute Auflösungsvermögen des Verfahrens. Die Methode wurde routinemäßig in der Umweltanalytik eingesetzt.

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On leave from Faculty of Chemistry, University of Sofia, Sofia, Bulgaria.     

Novel one-dimensional structures and solution behaviour of copper(II) bromide and chloride complexes of a new pentapyridyldiamine ligand

Copper(II) bromide and chloride complexes of the new heptadentate ligand 2,6-bis(bis(2-pyridylmethyl)amino)methylpyridine (L) have been prepared. For the bromide complexes, chains of novel, approximately C2-symmetric, chiral [Cu2(L)Br2]2+ 'wedge-shaped' tectons are found. The links between the dicopper tectons and the overall chirality and packing of the chains are dictated by the bromide ion content, not the counter anion. In contrast, the chloride complexes exhibit linked asymmetric [Cu2(L)Cl3]+ tectons with distinct N3CuCl2 and N4CuCl2 centres in the solid. The overall structures of the dicopper bromide and chloride units persist in solution irrespective of the halide. The redox chemistry of the various species is also described.     

Microwave spectrum,centrifugal perturbation,and dipole moment of acetyl chloride

An analysis of the microwave spectrum of acetyl chloride (¹²CH₃ ¹²C¹⁶O³⁵Cl) in the ground vibrational state allowed us to determine the quartic constants of centrifugal distortion and to refine the rotational constants and the constants of quadrupole coupling of³⁵Cl nuclei in this compound. The Stark effect of the 0–1₁₁ transition has been measured and analyzed. The components of the dipole moment have been determined: μ_a=1.047(10) D and μ_b=2.503(4) D. The total dipole moment of the moment of the molecule is 2.713(8) D. Ufa Scientific Center of Russian Academy of Sciences, Physics Department. Translated fromZhurnal Struktumoi Khimii, Vol. 36, No. 3, pp. 424–429, May–June, 1995. Translated by I. Izvekova     

An electron diffraction determination of the molecular structures of phosphoryl bromide and thiophosphoryl bromide

Gas-phase electron diffraction structures have been determined for phosphoryl bromide (OPBr₃ thiophosphoryl bromide (SPBr₃Normal coordinate analyses were carried out for the two molecules using a valence force field, and the resulting amplitude terms used for transformations between r_a and r_ga. An unconstrained refinement of the OPBr₃ intensities gives the parameters r_g(PO) = 1.455(7) Å and r_g(PBr) = 2.175(3) Å. The weighted average, geometrically-consistent valence angles derived from the four internuclear distances, r_α, are θ_α(OPBr) = 114.4(2)° and θ_α(BrPBr) = 104.1(2)°. For SPBr₃ a constrained fit to a self-consistent rα structure gives the parameters r_g(PS) = 1.895(4) Å, r_g(PBr) = 2.193(3) Å, θ_α(SPBr) = 116.2(2)°, and θ_α(BrPBr) = 101.9(2)°. Electron diffraction and spectroscopic vibrational amplitudes are reported for both molecules. The electron diffraction structures are compared with those predicted by simple models previously developed to describe main group V trihalides and trihalogen oxides and sulfides. Treatment of valence angles in four-coordinate molecules is found to be the least satisfactory feature of these models.