Zur Chemie des Bis(methylsulfonyl)-amins (Dimesylamins). III. Onium-Salze des Dimesylamins

Investigations on Bis(methylsulfonyl)-amine (Dimesylamine). III. Onium Salts of Dimesylamine Thirty-five salts of the strong acid HN(SO₂Me)₂ containing onium cations are reported. These include higher quaternary ammonium salts which show excellent solubility in solvents of low polarity, thus being particularly useful for preparing solutions of “naked” (MeSO₂)₂N^? or corresponding ion-pairs. Pyrolysis of the quaternary ammonium salts at temperatures of 200—250°C produces tertiary amines and N-alkyl-dimesylamines by (N → N′)-alkyl transfer. Alkene formation is not observed.     

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.     

Etude par Spectrométrie de Masse de la Fragmentation d'une Série de Diols Aliphatiques

The mass spectrometric fragmentation of a series of diols having the general formula HO? (CH₂)_n? OH with n = 2-11 has been studied. Extensive labelling of n-butane-1,4 diol and n-hexane-1,6 diol with deuterium allows fragmentation modes to be proposed. The labelling reveals that intramolecular exchange of H atoms often precedes the fragmentation and becomes more important when the length of the chain increases.     

Neue Koordinationsverbindungen aus Triorganylzinn(IV)-dimesylamiden und Neutralliganden: Einkern- und Mehrkernkomplexe mit molekularer oder ionischer Kristallstruktur

Polysulfonylamines. CII. New Coordination Compounds Derived from Triorganyltin(IV) Dimesylamides and Uncharged Ligands: Mononuclear and Polynuclear Complexes with Molecular or Ionic Crystal Structures The purpose of this report is to draw attention to the remarkable versatility of the dimesylamides R₃SnA [A^– = (MeSO₂)₂N^–; R = Me ( 1 a ) or Ph ( 1 b )] as precursors for pentacoordinate triorganyltin(IV) complexes belonging to four distinct structural types. Representative complexes were prepared by treating 1 a or 1 b in the appropriate molar ratios with unidentate thiourea or urea-type ligands or with the bidentate ligand [Ph₂P(O)CH₂]₂ (DPPOE). The following compounds were characterized by X-ray analysis: [Me₃Sn(A)(thiourea)] ( 2 a ; monoclinic, space group P2₁/n), [Ph₃Sn(A)(tetramethylthiourea)] ( 2 b ; monoclinic, P2₁, two independent formula units), [Me₃Sn(1-methylurea)₂]⁺ · A^– ( 3 a ; monoclinic, P2₁/c), [Ph₃Sn(1,1-dimethylurea)₂]⁺ · A^– ( 3 c ; triclinic, P1), [{Ph₃Sn(A)}₂(μ-dppoe)] ( 4 ; triclinic, P1), [Ph₃Sn(μ-dppoe)]_nⁿ⁺ · n A^– · n MeCN ( 5 ; monoclinic, P2₁/c). The lattices of 2 a , 2 b and 4 contain discrete uncharged formula units which are mononuclear for 2 a and 2 b or dinuclear for 4 , whereas 3 a , 3 c and 5 have ionic structures featuring mononuclear cations for 3 a and 3 c or an infinite linear-polymeric cation for 5 . In all the structures, the tin atoms adopt trigonal-bipyramidal geometries, the apical positions being occupied in 2 a and 2 b by the S atom of the thiourea and one O atom of A^–, in 3 a and 3 c by the O atoms of two urea-type ligands, in 4 by an O atom of the bridging DPPOE molecule and one O atom of A^–, and in 5 by two phosphoryl O atoms from different bridging DPPOE ligands. In the structures of 2 a , 3 a and 3 c , the (thio)urea NH functions are connected to A^– via intermolecular or interionic N–H … O and N–H … N hydrogen bonds. Crystals of [{Me₃Sn(bipyH⁺ … A^–)}₂(μ-bipy)]²⁺ · 2 A^– ( 6 ; monoclinic, C2/c) formed adventitiously in a reaction mixture containing 1 a and 4,4′-bipyridine. The rod-like supramolecular cation of 6 (length ca. 4 nm) is built up from two Me₃Sn⁺ units bridged through bipy and unidentally coordinated by a monoprotonated bipy (= bipyH⁺), resulting in a trigonal-bipyramidal geometry around tin (N atoms apical); each of the terminal bipyH⁺ ligands forms an ⁺N–H … N^– hydrogen bond with one A^–.     

Polysulfonylamines. CXXXII.

The crystal structure of the title compound, C₅H₇N₂⁺·C₁₂H₁₀NO₄S₂⁻, consists of two independent cation–anion pairs, A and B. Within each pair, the H—N—C—N*—H grouping (N*—H is the pyridinium function) and one N—S—O moiety of the anion are linked by N*—H⃛N and N—H⃛O hydrogen bonds to form an antidromic ring motif of type R²₂(8). The remaining amino donors give rise to N—H⃛O hydrogen bonds, connecting the ion pairs into A–B–A–B– chains. The structure testifies to the persistence of the R²₂(8) motif in question, which was previously detected as a highly robust supramolecular synthon in a series of onium di(methane­sulfonyl)­amidates. The structure is pseudosymmetric; the anion positions correspond to space group P2₁/n, but those of the cations do not.     

Poly­sulfonyl­amines. CXLV.

The prominent features in the molecular structure of the title compound (alternative name: 2‐diethyl­carbamoyl‐1,1,3,3‐tetraoxo‐1,3,2‐benzodi­thia­zole), C₁₁H₁₄N₂O₅S₂, arise in the urea moiety S₂N—C(O)—N′C₂: the sum of the angles at N is 332.3 (1)°, the N—C(O)—N′C₂ unit is planar, and distances N—C(O) = 1.494 (3) Å, N′—C(O) = 1.325 (2) Å and C—O = 1.215 (2) Å. The mol­ecules are associated via five C—H?O hydrogen bonds to form layers parallel to the yz plane. This compound and its di­methyl homologue, which were synthesized by treating the silver salt of o‐benzene­disulfon­imide with carbamoyl chlorides, are prone to rapid hydro­lysis at the weak N—C(O) bond. For both mol­ecules, the rotational barrier about the partial N′—C(O) double bond is ca 50 kJ mol^?1 at 250 K (from dynamic ¹H NMR experiments).     

Kristallstrukturen des freien protonierten Liganden HN(SO2)2C6H4 (= HZ) und des lamellaren Caesiumsalzes CsZ

Metal Salts of Benzene‐1,2‐di(sulfonyl)amine. 3. Crystal Structures of the Free Protonated Ligand HN(SO₂)₂C₆H₄ (= HZ) and the Lamellar Cesium Salt CsZ Benzene‐1,2‐di(sulfonyl)amine ( 1 ; HZ), known since 1921, is a very strong NH acid and readily reacts with aqueous CsCl to form crystalline CsZ ( 3 ). For both compounds, crystal structures were determined by X‐ray diffraction at –100 °C ( 1 : monoclinic, space group P2₁/n, Z = 4; 3 : orthorhombic, Cmcm, Z = 4). In 1 , the five‐membered 1,3,2‐dithiazole heterocycle possesses an envelope conformation, the N atom lying 29.4(2) pm outside the mean plane of the S–C–C–S moiety [S–N 167.06(15) and 167.53(15) pm, S–N–S 114.57(8)°]. In the crystal, HZ molecules are linked into chains by a conventional N–H…O hydrogen bond and further associated via four weak C–H…O bonds to form a three‐dimensional network. The conjugate Z^⊖ ion in the layered structure of the salt 3 displays crystallographic C_2v symmetry, leading to an ideally planar bicyclic framework [S–N 158.29(15) pm, S–N–S 116.53(17)°]. Each of the five electronegative atoms bridges two cations, Cs^⊕ attaining a tenfold coordination by forming bonds to two (O,N,O)‐chelating and four κ¹O‐monodentate ligands. The Cs–O/N interactions create a polar [CsN(SO₂)₂]_∞ lamella, which is lipophilically wrapped by parallel benzo rings protruding perpendicularly from its surfaces. In contrast to the previously reported lamellar metal di(arenesulfonyl)amides, the aromatic groups pertaining to adjacent layers of 3 are seen to be markedly interlocked.     

Eine Methode zur Darstellung und Bestimmung des Glykogens

Ohne Zusammenfassung     

Ichthyosan in fish eye

Ichthyosan A and V are two highly elastoviscous glycan complexes present in the aqueus and vitreus [here aqueus and vitreus are used as nouns as was suggested by Balazs and Denlinger in The eye, vol 1A. Vegetative physiology and biochemistry, 3rd edn. Academic Press, New York, pp 533–589, 1984] of the fish eye. Ichthyosan A, with its high elastic properties, surrounds and stabilizes the lens of the eye. Ichthyosan V, within the collagen fibers, serves as a structure stabilizer of the gel vitreus. These two molecular complexes are non-covalent aggregates composed of hyaluronan, a chondroitin-proteoglycan (sulfate free), and a keratan-like molecule. The ratio of hyaluronan to chondroitin–proteoglycan varies in the two ichthyosans. Electrophoretic separation methods (both free and gel electrophoresis) demonstrate that the hyaluronan–proteoglycan aggregates move as one molecular entity. The average molecular weight of the ichthyosan varies from 5.2 to 13.0 million in various species. Aquatic mammals do not have ichthyosan in their eyes.     

Dynamic updates of the barrier parameter in primal-dual methods for nonlinear programming

We introduce a framework in which updating rules for the barrier parameter in primal-dual interior-point methods become dynamic. The original primal-dual system is augmented to incorporate explicitly an updating function. A Newton step for the augmented system gives a primal-dual Newton step and also a step in the barrier parameter. Based on local information and a line search, the decrease of the barrier parameter is automatically adjusted. We analyze local convergence properties, report numerical experiments on a standard collection of nonlinear problems and compare our results to a state-of-the-art interior-point implementation. In many instances, the adaptive algorithm reduces the number of iterations and of function evaluations. Its design guarantees a better fit between the magnitudes of the primal-dual residual and of the barrier parameter along the iterations.