Etude par RMN du proton d'hétérocycles voisins de l'oxazaphospholane-1,3,2. I—La phényl-3 oxo-2 oxathiazolidine-1,3,2

A complete analysis of the ¹H NMR spectrum of the title compound is used for the conformational assignment of the molecule in the C-4—C-5 region. The position of protons is related to the position of the S?O bond with the help of a europium complex Eu(fod)₃. The results obtained are consistent with those found for similar compounds with or without a phosphorus atom.     

Etude en Résonance Magnétique Nucléaire et Stéréochimie d'un Composé Cyclopropanique d'Intérět Thérapeutique. Résonance du Proton à 250 MHz avec Triple Irradiation

1-Pivaloyl-2-hydroxymethylcyclopropane is studied with nuclear magnetic resonance. The C-1? C-2 configuration is determined from the 250 MHz n.m.r. spectrum (triple irradiation experiments have been performed for this purpose). Rotational isomerism around the ring-carbonyl bond is studied from the ASIS effect. Rotational isomerism around the ring-hydroxymethyl bond is studied from vicinal coupling constants over a temperature range of ?20 to +125°C. From the J(HOCH) coupling constant (in CCl₄) rotamer populations of the hydroxyl group are examined and the overall conformational distribution can be established.     

Element-Element-Bindungen. VI. Kristallines 2-Chlor-1,3,2-benzoxathiastibol – ein mehrfach verknüpftes Koordinationspolymeres

Element-Element-Bonds. VI. Crystalline 2-Chloro-1,3,2-benzoxathiastibole – a Multiply Linked Coordination Polymer Yellow 2-chloro-1,3,2-benzoxathiastibole 4a first prepared by Anchisi and coworkers [3] from o-hydroxythiophenol and antimony trichloride, crystallizes in the monoclinic space group P2₁/n {a = 1109.9(3); b = 610.5(2); c = 1201.5(2) pm; β = 100.35(2)° at ?120 ± 3°C; Z = 4}. An X-ray structure determination (R = 0.029) shows the molecules to form coordination polymeric layers via Sb…?Cl, Sb…?O and Sb…?η²-arene interactions in the solid. Characteristic structural features are Sb? Cl…?Sb? Cl helices (Sb? Cl…?Sb 119°; Cl? Sb…?Cl 95°) and centrosymmetric, four membered Sb₂O₂-rings (O? Sb…?O 64°; Sb? O…?Sb 116°). The ligands set up a strongly distorted octahedron around the antimony atom: Sb? S 242; Sb? Cl 243; Sb…?Cl 328; Sb? O 201; Sb…?O 287; Sb…?C 338 and 341 pm; S? Sb? O 85°; S? Sb? Cl 94°; O? Sb? Cl 92°.     

Enriched 13C NMR of a metallated α-sulphinyl ester; temperature effect

Lithium and magnesium enolates of an α-sulphinyl ester 83% ¹³C enriched at C-1 and C-2 are studied by ¹³C NMR at different temperatures. It is shown that two metaliated species are present in the case of lithium which exchange at ?60°C, ΔG≠ ?60° = 37.8 KJ mol^?1 (9.05 Kcal mol^?1) and that there is no rapid exchange between the non-metallated ester and the metallated species (on the NMR time scale). In the case of magnesium, two or three metallated species are formed, according to the temperature which do not exchange up to 0 °C.     

Etude par RPE des radicaux libres daus le tétraoxane irradié

The free radicals induced in tetraoxane at liquid nitrogen temperatures by ⁶⁰Co γ-rays have been studied by ESR. The powder spectrum as well as he spectra of the single crystal rotated around the b axis have been studied through their modifications from ?196°C up to + 80°C. These spectra show that at low temperatures two radicals exist conserving the cyclic nature of the parent molecule. During the course of annealing, starting at ?140°C and towards ?85°C they are gradually replaced by radicals with a linear structure, this being the first step in the post-polymerization process of tetraoxane. Further increase in temperature leads to radical sites situated on the polymer chains. At low temperatures evidence has also been found for the formyl radical, radical pairs, and a photo-sensitive radical.     

Etude de composés d'addition d'acides de Lewis,XXXIV [1] Composés d'addition de benzoquinone-1, 4 avec TiCl4

The adduct 1,4-benzoquine · TiCl₄ has been prepared in CH₂Cl₂ solution at about ?60°. Its IR. spectrum has been recorded at the same temperature. The experimental study of the vibrational frequencies has been completed by the calculation of the fundamental vibrations in the molecular plane, using Wilson's FG method, with slightly simplified models of 1,4-benzoquinone · TiCl₄ (13 masses) and 1,4-benzoquinone · 2 TiCl₄ (14 masses); analysis by use of internal and symmetry coordinates. An assignment of most of the observed bands is proposed and the conclusion is reached that the complex, when solid, is (1,4-benzoquinone · TiCl₄)_n. The force constants F(C? O) are 9,85 · 10⁵ dyne/cm for the quinone and 8,8 · 10⁵ dyne/cm for the disturbed carbonyl bond of the polymerized complex in the model proposed. At ordinary temperature in benzene solution of the components the adduct 1,4-benzoquinone. TiCl₄ · benzene precipitated; with the help of the models, the fundamental vibrations of its IR. spectrum have been assigned.     

ESR spectra of poly(methacrylic acid) and poly(methyl methacrylate): Reinterpretation of the 9-line spectrum

The temperature dependence of the ESR spectra of poly(methacrylic acid) and poly-(methyl methacrylate) γ-irradiated at room temperature was studied between ?196°C and +25°C. The conventional 9-line spectrum was observed throughout this range with no significant spectral change, in contrast to the propagating radical ··· CH₂? °C(CH₃)COOR found in methacrylic acid monomer or barium methacrylate dihydrate irradiated at ?196°C. In addition, the irradiation of methacrylic acid monomer with a low dose at 0°C gave the same 13-line spectrum as that of the propagating radical obtained by the irradiation at ?196°C, while prolonged irradiation at 0°C gave the same conventional 9-line spectrum as that of poly(methacrylic acid) or poly(methyl methacrylate). The conventional 9-line spectrum has a much weaker 4-line component than that of the propagating radical. The difference comes from the surrounding matrix, and the conventional 9-line spectrum is well interpreted by introducing the concept of the distribution of the conformational angle in the irregular polymer matrix. From simulation of the ESR spectrum, it was found that the intensity of the 4-line component is very sensitive to the distribution, and that the observed 9-line spectrum is well reproduced assuming a Gaussian distribution (half-height width of 5–6°) around the most probable conformation which is nearly the same as that of the propagating radical, where the conformational angles of the two C? H_β bonds to the half-filled p-orbital are 55° and 65°.     

Über Chalkogenolate. 93. Untersuchungen über Trithioallophansäure 2. Darstellung und Eigenschaften der freien Säure [1]

On Chalcogenolates. 93. Studies on Trithioallophanic Acid 2. Preparation and Properties of the Free Acid Yellow trithioallophanic acid H₂N? CS? NH? CS(SH) has been prepared by reaction between a suspension of K[S₂C? NH? CS? NH₂] in diethyl ether and a solution of HCl in (C₂H₅)₂O at ?15°C; the ether was distilled off at ?15°C in vacuo. The compound has been characterized by means of infrared spectra, electron absorption, ¹H-NMR spectra, and mass spectra. The dissociation constant of trithioallophanic acid in water is K_a = (1,41 ± 0,08) · 10^?2 at 20°C.     

Polysulfonylamine. XLII. Ein Aquasilber(I)-Komplex mit einem Ag(m̈-H2O)2Ag-Strukturmotiv: Röntgenstrukturanalytische und thermoanalytische Charakterisierung von Aqua(1,1,3,3-tetraoxo-1,3,2-benzodithiazolido)silber(I)

Polysulfonyl Amines. XLII. An Aquasilver(I) Complex with an Ag(m?-H₂O)₂Ag Structural Unit: Characterization of Aqua(1,1,3,3-tetraoxo-1,3,2-benzodithiazolido)silver(I) by X-Ray Diffractometry and Thermal Analysis The title compound C₆H₄(SO₂)₂NAg · H₂O, where C₆H₄(SO₂)₂N^º is the anion of 1,2-benzenedisulfonimide, crystallizes in the monoclinic space group C2/m with (at ?95°C) a = 1 129,7(3), b = 1 196.1(3), c = 810.7(2) pm, β = 124.25(2)°, V = 0.9055 nm³, Z = 4, D_x = 2.524 Mg m^?3. The crystal packing consists of [Ag(m?-H₂O)₂Ag{m?-C₆H₄(SO₂)₂N}₂]_n bands with crystallographic mirror symmetry, associated into layers by H-bonds with O(W)—O(S) 289.7 pm. The Ag(m?-H₂O)₂Ag moiety forms a planar four-membered ring with Ag? O(W)? Ag 97.3°, O(W)? Ag? O(W) 82.7° and Ag°Ag 372.1 pm. In the Ag{C₆H₄(SO₂)₂N}₂Ag′ unit, the anions act as tridentate (N, 1-O, 3-O)-ligands: One is N-bonded to Ag and O,O-chelated to Ag′, the other N-bonded to Ag′ and O,O-chelated to Ag. The silver atoms are (O₄N)-pentacoordinate, with nitrogen in the apical position of a distorted square pyramid [Ag? N 223.6, Ag? O(W) 247.8, Ag? O(S) 259.4 pm]. The thermochemical behaviour of the hydrate was investigated by thermal analysis and calorimetry. Water is only released at temperatures above 220°C. The dehydration enthalpy at 298 K is + 13.9 kJ mol^?1.     

Constitution moléculaire d'α,ω-difluoropolydiméthyl-N-méthylsilazanes. Equilibres obtenus par une réaction de redistribution

Unlike the α,ω-dihalogenopolydimethylsiloxanes, the α,ω-dichloropolydimethyl-N-methylsilazanes show a net preference for cyclic species with respect to linear structures at equilibrium. The aim of this study is to evaluate the perturbations in the molecular constitution of these α,ω-dihalogenopolydimethyl-N-methylsilazanes resulting from the substitution of the terminal chlorine atoms by fluorine atoms. This polymeric family was prepared by reacting (CH₃)₂SiF₂ with nonamethylsilazane [(CH₃)₂SiNCH₃]₃. The redistribution of the fluorine atoms with the bridging methylimino groups reached an equilibrium after about 5 months' heating at 150°C for all the samples prepared. The relative abundance of the various molecular species and fragments at equilibrium was deduced from the quantitative analysis of the proton nuclear magnetic resonance (NMR) spectra. The molecular constitution at equilibrium is described by two constants. The first, K = [neso] [middles in chains]/[terminal moieties]² = (2.8 ± 0.8) 10^?2, shows that the presence of terminal fluorine atoms is unfavorable to the formation of short chains. On the other hand, the trimeric cyclic species [(CH₃)₂SiNCH₃]₃ are found to be highly favored (K°₃ = 550 ± 100 mole/liter). These observations further confirm that the equilibrium constants which control the noncyclic part of polymeric families depend little on the functionality of the substituents exchanged [for example, on changing from ? N(CH₃)₂ to ? NCH₃? ] when the reorganization heat order is one.     

A 13C NMR study of some derivatives obtained from iron carbonyls and diphenylacetylene

The molecule Fe₂(CO)₇(PhC₂Ph)₂ has been studied by ¹³C NMR and is static at ?40°C with a spectrum which is consistent with the known structure observed in the crystals. In the range ?40 to +41°C the three carbonyl resonance coalesce possibly by a single carbonyl averaging process. At room temperature violet Fe₃(CO)₈(PhC₂Ph)₂ is found to be static by ¹³C NMR having a spectrum consistent with the known solid state structure. Dark green Fe₃(CO)₈(PhC₂Ph)₂ is static via ¹³C NMR at ?62°C with a spectrum consistent with the known solid state structure. Between ?62 and +96°C a fluxional process occurs which scrambles the bridge carbonyls and four of the six terminal carbonyl groups. In this process the bridging carbonyls appear to be preferentially moving toward the iron atoms with which they have the shortest iron-carbon bond as observed in the solid state structure.     

Etude par résonance paramagnétique électronique du radical (ΦNH)2P• piégé dans un monocristal de diphenylamino-phosphineoxyde irradié aux rayons X

The radical (ΦNH)₂P· is trapped by annealing at 100°C an X-irradiated single crystal of N? N diphenyl phosphondiamide and has been studied by electron spin resonance. The isotropic and anisotropic ³¹P coupling constants are discussed. The principal values and direction cosines of the g tensor are also given.     

3-Chloro-1,2,3,4-tetraphenylcyclobutenyl-Ennea-chloro-μ-Oxo-di-Niobat(V),[C4Cl(Ph)4]⊕[Nb2OCl9]⊖ Synthese und Kristallstruktur

3-Chloro-1,2,3,4-tetraphenylcyclobutenyl-Ennea-chloro-μ-Oxo-di-Niobate(V), [C₄Cl(Ph)₄]^⊕[Nb₂OCl₉]^?. Synthesis and Crystal Structure The title compound yields from a one step reaction of niobium pentachloride and niobium oxide trichloride with diphenyl acetylene in dichloro methane, forming dark green crystals. The new complex is characterized by the i.r. spectrum and a crystal structure determination by X-ray methods. The compound crystallizes triclinic in the space group P1 with two formula units per unit cell (2253 independent observed reflexions, R = 4.7%). The lattice dimensions are a = 1199, b = 1034, c = 1453 pm; α = 87.0°, β = 108.6°, γ = 96.6°. The cyclobutenyl cation forms an almost planar C₄-ring with two pairs of neighbouring C? C bonds of 139 pm and 153 pm. The anion [Nb₂OCl₉]^? displays a nearly linear NbONb axis (bond angle 174°) in which the NbO bond lengths are 176 pm and 208 pm. Two anions are linked via asymmetric chloro bridges with Nb? Cl bond lengths of 248 pm and 270 pm to form a centrosymmetric dimer.     

Poly(alkylene oxide) ionomers IX. Polymerization of methyl ω-epoxyalkanoates and characterization of the polymers

Polymerization of linear methyl ω-epoxyalkanoates of C-3 to C-10 carboxylic acids (0 to 7 methylene groups between oxirane ring and carbomethoxy group) was accomplished with a triethylaluminum/water/acetylacetone (1.0/0.5/1.0) initiator system to yield polymers of high molecular weight, apparently via a coordinative anionic mechanism. The rate of polymerization increased as the number of methylene groups between the oxirane ring and the carbomethoxy group increased, up to three methylene groups. When more than three methylene groups separate the polymerizable oxirane group and the carbomethoxy group, the rate of polymerization becomes essentially constant. The polymers were characterized by their infrared and ¹³C-NMR spectra, DSC, GPC, and inherent viscosity. The lower members of the series (ω-epoxyalkanoates of n < 3) gave polymers of lower molecular weight and wider-molecular-weight distribution (M _w/M _n > 2), while the higher members had molecular weight distributions between 1.5 and 2. The glass transition temperatures of the polymers also decreased from ?26°C for n = 1 to around ?50 to ?55°C for n ≥ 3.     

Etude par Résonance Magnétique Nucléaire de dérivés phosphores. Etude de dithiaphospholanes-1,3,2

The proton NMR spectral analysis of eight different 1,3,2-dithiaphospholanes with various groups attached to the phosphorus atom has been performed. The AA′BB′X (X phosphorus atom) system shows that the two ³J(P? S? C? H) coupling constants have a small magnitude and opposite signs. Using the ³J(HH) values, the torsion about the C₄—C₅ bond has been evaluated. The conformational requirements in the two isomers of the 2 phenyl-4-methyl-1,3,2-dithiaphospholane are also discussed.     

Synthesis of well‐defined syndiotactic poly(methyl methacrylate) with low‐temperature atom transfer radical polymerization in fluoroalcohol

The copper‐mediated atom transfer radical polymerization of methyl methacrylate (MMA) in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) was studied to simultaneously control the molecular weight and tacticity. The polymerization using tris[2‐(dimethylamino)ethyl]amine (Me₆TREN) as a ligand was performed even at ?78°C with a number‐average molecular weight (M_n) of 13,400 and a polydispersity (weight‐average molecular weight/number‐average molecular weight) of 1.31, although the measured M_n's were much higher than the theoretical ones. The addition of copper(II) bromide (CuBr₂) apparently affected the early stage of the polymerization; that is, the polymerization could proceed in a controlled manner under the condition of [MMA]₀/[methyl α‐bromoisobutyrate]₀/[CuBr]₀/[CuBr₂]₀/[Me₆TREN]₀ = 200/1/1/0.2/1.2 at ?20°C with an MMA/HFIP ratio of 1/4 (v/v). For the field desorption mass spectrum of Cu^IBr/Me₆TREN in HFIP, there were [Cu(Me₆TREN)Br]⁺ and [Cu(Me₆TREN)OCH(CF₃)₂]⁺, indicating that HFIP should coordinate to the Cu^I/Me₆TREN complex. The syndiotacticity of the obtained poly(methyl methacrylate)s increased with the decreasing polymerization temperature; the racemo content was 84% for ?78°C, 77% for ?30°C, 75% for ?20°C, and 63% for 30°C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1436–1446, 2006     

Das Lanthaniodidethanid o‐La5I9(C2) – Die orthorhombische Hochtemperaturmodifikation

The Lanthanumiodideethanide o‐La₅I₉(C₂) – The Orthorhombic High Temperature Modification o‐La₅I₉(C₂) is synthesized by reaction of LaI₃, La metal and graphite powder in sealed Ta containers at 850 °C < T < 900 °C. It crystallizes in the orthorhombic space group Pbca with a = 8.0247(16) Å, b = 16.887(3) Å, c = 35.886(7) Å. o‐Ce₅I₉(C₂) is isotypic with the lattice parameters a = 7.9284(4) Å, b = 16.714(1) Å, c = 35.530(3) Å. o‐La₅I₉(C₂) transforms at 800 °C to the triclinic low temperature modification t‐La₅I₉(C₂). The transformation is reversible. The La atoms form trigonal bipyramids centered by C₂ groups. These units are connected by iodine atoms above the faces (f), edges (e) and corners according to La₅(C₂)I(f)ⁱI(e)^i?i_2/2I(e)^i?a_7/2I(e)^a?i_7/2. The C‐C distance in the C₂ unit is 1.45(2) Å. The crystals with greenish luster are moisture sensitive.     

Nuclear magnetic resonance of phosphorus compounds: 9—The NMR spectra of phosphirane

The 100 MHz proton and 40.4 MHz ³¹P NMR spectra of phosphirane (1) have been recorded at ?20 °C and analysed iteratively to yield coupling constants and chemical shifts. The 22.6 MHz ¹³C spectrum of 1 was recorded at 0 °C and analyzed. The ³¹P chemical shift of 1 was measured as 40 467 515.97 ± 0.08 Hz relative to TMS as 100 000 000.00 Hz. The geminal P-C-H couplings in 1 are opposite in sign and of different magnitudes (+16.14 and ?2.64 Hz); the P? H coupling (+158.34 Hz) is smaller than that in any other organic phosphine. These observations are discussed and correlated with the geometry of 1. The electronic structure of the strained ring of 1 is discussed in terms of a localized valence bond approach.     

Stéréochimie en série aziridine: VI—Etude en Résonance Magnétique Nucléaire d'alcools aziridiniques primaires (configuration à l'azote,isoméries de rotation)

The PMR spectra of six primary aziridinyl carbinols are studied over a temperature range of ?30°C to +100°C. Nitrogen configuration is determined. When the inversion process is effective, kinetic parameters are evaluated. Rotational isomerism about the ‘ring? CH₂OH’ bond is studied from vicinal coupling constants associated with the two diastereotopic protons on the ? CH₂OH group. From the J(HOCH) coupling constant (in CCL₄) rotamer populations of the hydroxyl group are determined in some cases and the overall conformational distribution can be established.     

Polysulfonylamine. XL Darstellung von Silber(I)-disulfonylamid-Acetonitril-Komplexen. Röntgenstrukturanalytische und thermochemische Charakterisierung von Tetraacetonitrilsilber(I)-bis(dimesylamido)argentat(I) und von (1,1,3,3-Tetraoxo-1,3,2-benzodithiazolido)acetonitrilsilber(I)

Polysulfonyl Amines. XL. Preparation of Silver(I) Disulfonylamide Acetonitrile Complexes. Characterization of Tetraacetonitrilesilver(I) bis(dimesylamido)argentate(I) and (1,1,3,3-Tetraoxo-1,3,2-benzodithiazolido)acetonitrilesilver(I) by X-Ray Diffractometry and Thermal Analysis The following silver(I) disulfonylamides were prepared for the first time or by improved procedures: AgN(SO₂CH₃)₂ ( 2a ); AgN(SO₂C₆H₄-4-X)₂ with X = F ( 2b ), Cl ( 2c ), Br ( 2d ), CH₃ ( 2e ); silver(I) 1,2-benzenedisulfonimide AgN(SO₂)₂C₆H₄ ( 2f ). With acetonitrile, the salts 2a to 2e form (1/2) complexes AgN(SO₂R)· 2 CH₃CN ( 4a to 4e ), whereas 2f gives the (1/1) complex AgN(SO₂)₂C₆H · CH₃CN ( 4f ). The crystallographic data (at - 95°C) for the title compounds 4a and 4f are: 4a , space group C2/c, a = 1 967.6(4), b = 562.2(1), c = 2 353.0(5) pm, β = 102.21(2)°, V = 2.5440 nm³, Z = 4, D_x = 1.891 Mg m^?3; 4f , space group P2₁/m, a = 741.5(3), b = 980.4(4), c = 756.6(3) pm, β = 99.28(2)°, V = 0.5428 nm³, Z = 2, D_x = 2.246 Mg m^?3. 4a forms an ionic crystal [Ag(NCCH₃)₄]^⊕[Ag{N(SO₂CH₃)₂}₂]^? with a tetrahedrally coordinated silver atom (lying on a twofold axis) in the cation (225.3/225.7 pm for the two independent Ag? N distances, N? Ag? N 106.2—114.5°) and a linear-dicoordinated silver atom in the centrosymmetric anion (Ag? N 213.9 pm, two intraionic secondary Ag…O contacts 303.4 pm). 4f consists of uncharged molecules [C₆H₄(SO₂)₂N¹AgN²CCH₃] with crystallographic mirror symmetry (Ag? N¹ 218.8, Ag? N² 216.1 pm, N¹? Ag? N² 174.3°), associated into strands by intermolecular secondary silver-oxygen contacts (Ag…O 273.8 pm, O…Ag…O 175.6, N? Ag…O 91.9/88.2°). The thermochemical behaviour of 4f was investigated using thermogravimetry, differential scanning calorimetry (DSC), time- and temperature-resolved X-ray diffractometry (TXRD), and solution calorimetry. The desolvation process occurs in the temperature range from 60 to 200°C and appears to be complex, although no crystalline intermediate could be detected. The desolvation enthalpy at 298 K was found to be + 26.8(4) kJ mol^?1. 4a is desolvated in two steps at - 15 to 60°C and 60 to 95°C (DSC), suggesting the formation of AgN(SO₂CH₃) · CH₃CN as an intermediate.