Volume 48, Issue 8

The title compounds were prepared from stoichiometric mixtures of the elements or from alkali metals (Na, K), NaX (KX) and MX (M = Al, In; X = P, As) at 1000 K. The crystal structures (Ibam, No. 72) are characterized by infinite chains of edge sharing tetrahedra ∞ 1 [MX 4/2 3- ] (M = Al, In; X = P, As) which are isoelectronic to SiS 2 . The vibrational spectra can be interpreted with respect to the symmetry P(2/m 2/c) 4 2 /m–D 4h of the isolated polymeric chain ∞ 1 [MX 4/2 3- ]. The assignment of the observed frequencies is supported by a normal coordinate analysis using the fragment method.

K 49 T1 108 was prepared from the elements (molar ratio K: Tl = 1:2) at 700 K. The crystal structure was determined by single crystal X-ray diffraction methods (a = 1728.7(1) pm, Pm 3, Z = 1, R = 0.086). It contains T1 12 icosahedra and Tl 12 truncated tetrahedra (Kasper polyhedra). 20 truncated tetrahedra form Tl 84 -polyhedra (Samson polyhedra) by sharing hexagonal faces. These polyhedra are connected by common edges. Folded Tl 13 -chains connect the icosahedra and the Samson polyhedra to a framework. The truncated tetrahedra are occupied by potassium atoms.

Various six-membered cyclic sulfur diimides (3a—f) were prepared by aminolysis of the bis(chloro-dimethylsilyl)sulfur diimide (2) using NH 3 (a) and primary amines RNH 2 [R = Me (b), Et (c), n Pr (d), n Bu (e), i Pr (f)]. Except for R = H, non-cyclic intermediates, the Si-monoamino- (7) and Si,Si′-diamino derivatives of 2 (8), were detetected for all groups R, including R = t Bu (g). The reaction between R 2 SiCl 2 and the sulfur diimide anion K[(NSN)SiMe 3 ] gave non-cyclic silanes (9,10) and the eight-membered rings of the type R 2 Si(NSN) 2 SiR 2 [R = Me (4), t Bu (5)] of which 5 was studied by X-ray analysis (monoclinic, space group P2 1 /c; planar ring system) and solid-state 15 N and 29 Si CP/MAS NMR spectroscopy. The ten-membered ring system 6 was obtained from the reaction between 1,2-dichlorotetramethyldisilane and bis(trimethylstannyl)sulfur diimide. All compounds were studied by 1 H, 13 C, 15 N and 29 Si NMR. The δ 15 N NMR data proved useful to distinguish between fluxional systems with fast E/Z—Z/E isomerization (non-cyclic compounds 8 and the ten-membered cycle 6). Hahn-Echo-extended (HEED) polarization transfer (INEPT) pulse sequences served to measure coupling constants 1 J( 29 Si 15 N amine ) for the compounds 3 and 8. This also proved that the magnitude of 1 J( 29 Si 15 N NSN ) must be small (< 1 Hz). In the case of the compounds 3, the rather small magnitude of both 1 J( 29 Si 15 N amine ) and 1 J( 15 N 1 H) (3a) indicated that the aminonitrogen atom adopts a pyramidal environment.

The structures of the Ag–Ge-zeolite Ag 3 HGe 7 O 16 ·4H 2 O and its pyrolyse products Ag 4 Ge 9 O 20 and Ag 2 Ge 4 O 9 consist of a network of linked (GeO 4 )-tetraedra and (GeO 6 )-octahedra. In this network there exist free channels, which can be used as transport paths through the structure by Ag + -ions. Impedance spectroscopic measurements show the loss of weakly bonded water at about 210°C and irreversible structural changes, which finally lead to the pyrolysis products. Lattice vibrations prevent a better Ag + -mobility, so the high expectations concerning the conductance properties could not be fulfilled. In all cases the main part of the resistance could be attributed to the grain boundaries between the crystals.

The melting diagram of the system Me 4 NF-H 2 O in the region 50-100 mol% H 2 O has been investigated for the first time, using DTA, DSC and temperature-dependent X-ray powder diffraction. Four crystalline hydrates Me 4 NF·xH 2 O were found, with x = 1,2.33,4 and 5, which decompose irreversibly above ca. 160°C and melt incongruently at 36°C, congruently at 46°C and again incongruently at 10°C, respectively. The crystal structure of each hydrate, except the already known one of the tetrahydrate, has been determined with MoKa diffractometer data. The monohydrate is rhombohedral with space group R3̄̄m and Z = 6 formula units per unit cell (hexagonal axes), the 2.33-hydrate monoclinic with P2 1 /n and Z = 12, and the pentahydrate tetragonal with I4̄2 m and Z = 2. The hydrogen-bonded H 2 O/F- structure is an isolated centrosymmetric [F 2 (H 2 O)2] 2- four-membered ring in the monohydrate, a rather open three-dimensional network in the 2.33-hydrate and a corrugated dense layer of fused fivemembered rings in the pentahydrate.

Gas electron diffraction data of (CH 3 ) 2 SbECH 3 E = S or Se, show that the predominant conformer is one where the dihedral angle defined by the E–C bond, the Sb–E bond and the presumed direction of the lone pair at the Sb atom falls in the range –45 to +45°. The Sb–S and Sb–Se bond distances are 241.4(8) and 255.5(3) pm, respectively.

The hexaethylcyclohexaarsoxane complexes [{M(CO) 3 } 2 {cyclo-(C 2 H 5 AsO) 6 }], M = Cr, Mo, W, 2-4 have been prepared by the reaction of (C 2 H 5 AsO) n with the respective metal hexacarbonyl in toluene and characterized by their IR and NMR spectroscopic data. For 2 the molecular structure was established by X-ray structural analysis. The 12 atoms of the As 6 O 6 ring form a flattened cuboctahedron in which the 6 oxygen atoms lie in the central equatorial plane. Cr(CO) 3 groups are coordinated facially by the upper and lower three arsenic atoms. An approximately S 6 symmetry is displayed by the Cr 2 As 6 O 6 core. Average values of respectively 116.3 and 98.9° are observed for the As–O–As and O–As–O angles in the hexadentate ligand. The ΕΙ-MS and 1 H NMR data for (C 2 H 5 AsO) n suggest that this alkylcycloarsoxane is present in solution as a mixture of species including trimers and tetramers so that a metal assisted ring expansion is required for the formation of 2-4.

The crystral structure of CCl 2 = NH–CCl 3 + SbCl 6 - is reported. The compound crystallizes in the monoclinic space group P2 1 /n with a = 11.086(11), b = 9.973(12), c = 14.478(17)Å, β = 106.69(9)°, Ζ = 4. The framework of the cation is planar, with C–N bond lengths of 1.488(7) and 1.280(5)Å. The cation and the anion have one short H ••• Cl contact of 2.313(2)Å.

para-Substituted β-ketodithiocinnamic acid dianions react with L 2 MCl 2 [M = Ni, L = PBu 3 ; M = Pd, L = PPh 3 ; M = Pt, L = PEt 3 , PBu 3 , PPh 2 Tol, 1/2 dppe, 1/2 2,9-dimethyl-1,10-phenanthroline (dmphen)] to give the 1,1-ethene dithiolate complexes L 2 M[S 2 C=CH-C(O)-C 6 H 4 p-OC n H 2n-1 ] (3: M = Ni, L = PBu 3 , n = 12; 4a, b: M = Pd, L = PPh 3 , n = 1,8; 5a: M = Pt, L = PEt 3 , n = 1; 5b, 5e-g; 5i: M = Pt, L = PPh 3 , n = 1,8,10,12,14; 5c, h: M = Pt, L = 1/2 dppe, n = 1,12; 5j: M = Pt, L = PPh 2 Tol, n = 12; 6 a-c M = Pt, L = 1/2 dmphen, n = 8, 12, 16); L 2 Pt[S 2 C=CH-C(O)-C 6 H 4 -p-C 12 H 25 ] (7 a, b: L = PPh 3 , 1/2 dmphen), (Ph 3 P) 2 Pt[S 2 C=CH-C(O)-C 6 H 4 -p-C 6 H 5 ] (8) and L 2 M[S 2 C=CH-C(O)-C 4 H 3 S] (9a: M = Pd, L = PPh 3 ; 9b: M = Pt, L = PEt 3 ; 9c: M = Pt, L = PPh 3 , 9d: M = Pt, L = 1/2 dppe). These compounds have been characterized by their UV, IR, 1 H, 13 C and 31 P NMR spectra.

The iminophosphine (Me 3 Si) 2 NP=NSiMe 3 (1) was found to add pentafluoroacetone (2) giving two oxaphosphiranes (3a,b) (isomer ratio 2:3), whereas trifluoromethylpyruvate (4) gave rise to both a three-membered and a five-membered ring system (ratio 2:1) containing λ 5 σ 4 -phosphorus (5a,b) (isomer ratio 5:4) and 6, respectively. Pentafluoropropene-2-ol (7) (tautomer of 2), and 1 form the diamidophosphite 8 in a [2+2] addition reaction. Two 1,2λ 5 σ 4 -oxaphosphols 10a,b (isomer ratio 5:1) were synthesized from bifunctional 2-trifluoroacetylphenol 9 and 1. Hexafluoroacetone (11) added to 10a,b to yield only the λ 5 σ 4 -oxazaphosphetane (12).

The addition of amidines to 1,2,3-triketohydrindenhydrat gives cyclic dihydroxyindenoimidazoles. From N-substituted amidines mixtures of regioisomeric derivatives were obtained. Analysis of crystals revealed the major product of 2k to be 4k. They belong to the monoclinic space group P2 1 /c (a = 889.1(2); b = 1186.6(3); c = 2783.5(7) pm; β = 91.26(2)°) with Ζ = 8 molecules including four molecules of ethanole per unit cell. These results were confirmed by oxidation with lead(IV)acetate, which lead to derivatives of isoindols.

[WCl 4 (Ph-C≡C-I)(THF)] has been prepared by the reaction of trans-[WCl 4 (SEt 2 ) 2 ] with Ph - C≡C - I in THF solution, whereas [WCl 4 (Ph-C≡C-Te-nC 4 H 9 )(THF)] has been synthesized by the reaction of Ph-C≡C-Te-nC 4 H 9 with tungsten hexacloride in the presence of C 2 Cl 4 and THF. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. [WCl 4 (Ph-C≡C-I)(THF)]: Space group P2 1 /c, Z = 4, 2617 observed unique reflections, R = 0.064. Lattice dimensions at –70°C: a = 1518.2(3), b = 714.5(1), c = 1540.0(3) pm, β = 90.09(3)°. [WCl 4 (Ph-C≡C-Te–nC 4 H 9 )(THF)]. Space group P1̄, Z = 2, 3911 observed unique reflections, R = 0.067. Lattice dimensions at 20°C: a = 844.0(3), b = 974.6(4), c = 1002.4(3) pm, α = 76.00(4), β= 105.14(1), γ = 82.03(3)°. Both complexes have molecular structures, in which the tungsten atoms are seven-coordi-nate by four chlorine ligands, by the two alkyne carbon atoms, and in trans position to the latter by the oxygen atom of the THF molecule. The WC bond lengths are 198 and 200(1) in the telluro complex and 206 and 196(1) pm in the iodine derivative.

From the results of magnetic susceptibility and magnetization measurements of the triple chains ACrF 4 (A = K, Rb, Cs), the characteristics of one-dimensional antiferromagnetic chains are found. The exchange parameters J/k are —6.2 K and —12.2 K for KCrF 4 and CsCrF 4 , respectively. Measurements on single crystals of RbCrF 4 reveal the exchange and the anisotropy parameters to be J/k = —10.5 K and D/k = 0.4 K. The Mössbauer spectra of 2% 57 Fe doped CsCrF 4 show marked relaxation. One third of the magnetic chains are frustrated and remain uncorrelated with other magnetic chains.

Four new cerebrosides C-1 – C-4 were isolated from the latex of Euphorbia characias L. On the basis of spectral evidences and chemical reactions they were characterized as (2S, 3S, 4R, 5R, 6Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2′-hydroxy-(15′Z)-tetracosenoyl]-6(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-1), (2 S, 3 S, 4 R, 5 R, 6 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′ R)-2′hydroxy-(17′ Z)-hexacosenoyl]-6(Z)-octadecene-1,3,4,5-tetraol- 2-amino (C-2), (2S, 3S, 4R, 5R, 6Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′R)-2′-hydroxy-(19′Z)-octacosenoyl]-6-(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-3) and (2 S, 3 S, 4 R, 5 R, 6 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2′R)-2′-hydroxy-octacosanoyl]-6-(Z)-octadecene-1,3,4,5-tetraol-2-amino (C-4). Reversed phase column flash chromatography was effective for the isolation of the cerebrosides. FAB-MS spectrometry, 1 H NMR, 13 C NMR analysis and chemical reactions were useful in providing information for the structure elucidation.

The isobaric melting and boiling diagrams for the systems: pyridine/methyltrichlorosilane and pyridine/1,1,1-trichloroethane are reproduced. The existence of the congruently melting addition compound CH 3 SiCl 3 · (Pyridin) 2 could be confirmed. Some measurements of the molar volume of mixtures between pyridine and methyltrichlorosilane and pyridine and 1,1,1-trichloroethane, respectively, are reported. For both systems the molar excess volume and for the system pyridine/methyltrichlorosilane the molar excess enthalpie have been calculated as a function of the mole fractions.

The long-wavelength absorption of the dye formed at the ninhydrin-amino acid color reaction is caused by the anion (enolate) of diketohydrindamine-diketohydrindylidene (Ruhemann’s purple). Using the results of quantum-chemical calculations (MNDO, PPP) the basic chromophoric system was identified as two coupled five-membered rings which have partial anti-aromatic character like the antiaromatic cyclopentadienyl cation.

The unit cell of N-tert-butyl-3-(tert-butylimino)-2-nitropropen-1-amine (4) is monoclinic, space group P2 1 /C, with a = 9.669(4), b = 16.415(6), c = 17.341 (7) Å, and Z = 4. Hydrolysis of 4 leads to (E)-3-(N-tert-butylamino)-2-nitro-2-propenal (5), whose unit cell is monoclinic, space group P2 1 /n, with a = 6.821(1), b = 20.707(6), c = 6.303(1)Å, and Z = 4. Compounds 4 and 5 both possess C 2 symmetry in the solid state, their “U-shaped” conjugated cores being essentially planar. In each case this planarity is enforced by an intramolecular hydrogen bond.

The nephritogenoside trisaccharide unit was synthesized under mild conditions using phenyl 1-thioglycopyranoside sulfoxides as glycosyl donors. In the coupling process neither thiophenyl nor trityl protecting groups are cleaved from the carbohydrate moieties demonstrating the utility of this method also for oligosaccharide block syntheses.

Benzyl (–)-(2S)-1-trityl-2-aziridinecarboxylate (1) has been prepared by the reaction of N-trityl-L-serine benzyl ester and triethylamine in toluene with SO 2 Cl 2 . X-ray, 1 H NMR and gas chromatographic configuration analysis allowed to define the structure of the compound as a trans-isomer regarding ring substituents and as a (2 S)-enantiomer of the chiral C 2 .

Preparation and properties of the λ 5 -1,3-diphosphetium cation are described. The NMR data and some results of the X-ray structural analysis are discussed.

MgCl 2 (DME) 2 has been prepared by reaction of MgCl 2 with excess dimethoxyethane (DME) in n-pentane solution as white crystals, which are soluble in organic solvents. The crystal structure was determined by X-ray methods. Space group P2 1 /c, Z=4,2512 observed unique reflections, R=0.050. Lattice dimensions at –70°C: a = 1338.9(1), b = 845.1(1), c = 1315.3(2) pm, β = 112.69(1)°. The magnesium atom is in a distorted octahedral coordination by the two chlorine atoms in cis-positions and by the four oxygen atoms of two chelating 1,2-dimethoxyethane molecules.