Volume 35, Issue 2

Ether solutions of LiAlH 4 have been investigated by 27 Al and 7 Li magnetic resonance in the concentration range 3.75-0.0075 M. The Al-signal shows a fine structure due to Al-H coupling only at concentrations below 0.15 M. The observed chemical shift 27 Al is only slightly concentration dependent. The line width of the 27 Al signal, which is inversely proportional to T2*, reaches a minimum value at a concentration where the best resolution of the 27 Al quintet is observed. This, however, is not matched by the 7 Li line width whose minimum value was found at a somewhat higher concentration. The results are consistent with multiple ion formation at the higher concentrations and with an ion pair at low concentrations.

A series of bis(boryl)hydrazines X(CH 3 )B-CH 3 N-NCH 3 -B(CH 3 )X (X = F, Cl, Br, SCH 3 , N(CH 3 ) 2 , CH 3 ) has been prepared by various methods and investigated by NMR, MS and PE Spectroscopy. The new oxidative ring opening of 2, 3, 4, 5-tetramethyl-1-thia- 3,4-diaza-2,5-diborolidine by bromine to yield Br(CH 3 )B-CH 3 N-NCH 3 -B(CH 3 )Br and sulfur yields the syn/syn conformer which rapidly adopts also the syn/anti and the thermodynamically favoured anti/anti conformation. All bis(boryl)hydrazines possess planar geometry at the nitrogen atom as suggested by the 14 N NMR data and adopt gauche conformation as indicated by their He(I)-photoelectron spectra.

Crystals of the title compound are triclinic, a = 8.533(5), b = 11.106(6), c = 8.815(5) Å, a = 107.83(6), β = 104.99(6), γ = 81.30(5)°, Z = 2, space group P1̄. The structure was determined by multisolution direct methods and electron density methods. Refinement by least-squares techniques gave a final R = 0.081 for the 1753 independent reflections. The molecule adopts a butterfly-type conformation such that the fused phenyl rings are inclined to each other at an angle of 56.8°. The P-0 bond distance is 1.506(4) Å; the endocyclic angle at phosphorus is 107.2(3)° and the exocyclic angles vary from 106.5 to 111.9(3)°.

The new compounds BaBiSe 3 and BaSbTe 3 crystallize in the orthorhombic system, space group P2 1 2 1 2 1 with BaBiSe 3 : a = 1724 ± 2 pm, b = 1600 ± 2 pm, c = 437.0 ± 0.5 pm; BaSbTe 3 : a = 1809 ± 2 pm, b = 1694 ± 2 pm, c = 463.5 ± 0.4 pm. BiSe 6 - or SbTe 6 - octahedra, resp., are connected by common edges to fourfold strings. These are bound by additional chalcogen atoms to sheets, between which the Ba ions are located.

Ten new compounds with the general formula AB 2 P 2 (A = Ca, Sr, Eu, Ba; B = Cu, Ni, Co, Fe, Mn) have been prepared and their structures determined. They are isotypic and crystallize in the ThCr 2 Si 2 structure (space group I4/mmm) with the following constants: CaCu 1.75 P 2 a = 401.4 1 pm, c = 962.7(1) pm CaNi 2 P 2 a = 391.6 1 pm, c = 936.3(1) pm CaCo 2 P 2 a = 385.8 1 pm, c = 959.3(1) pm CaFe 2 P 2 a = 385.5 1 pm, c = 998.5(1) pm SrCu 1.75 P 2 a = 416.6 1 pm, c = 960.7(1) pm EUCU 1.75 P 2 a = 411.0 1 pm, c = 959.1(1) pm SrCo 2 P 2 a = 379.4 1 pm, c = 1161.0(1) pm SrFe 2 P 2 a = 382.5 1 pm, c = 1161.2(1) pm BaFe 2 P 2 a = 384.0 1 pm, c = 1244.2(1) pm BaMn 2 P 2 a = 403.7 1 pm, c = 1306.1(1) pm While in Ca(Sr,Eu)Cu 1.75 P 2 the P atoms form pairs, they are isolated from each other in the other compounds.

The secondary-tertiary diphosphines Ph 2 P(CH 2 ) 3 P(H)Ph (2) and Ph 2 P(CH 2 ) 3 P(H)Me (3) have been prepared from Ph 2 P(CH 2 ) 3 Cl (1) and NaP(H)Ph or LiP(H)Me, respectively. Metallation of 2 and 3 with n-butyl lithium and further reaction of the lithio-derivatives with one equivalent of 1 yields PhP[(CH 2 ) 3 PPh 2 ] 2 (4) and MeP[(CH 2 ) 3 PPh 2 ] 2 (5). The tritertiary phosphines 4 and 5 have likewise been obtained from RPLi 2 (R = Ph, Me) and two equivalents of 1. The synthesis of 4 from PhPCl 2 and two equivalents of the Grignard reagent of 1 is also reported. Each of the phosphines 1-5 was characterized by NMR and mass spectroscopy.

Cl 3 VNI crystallizes isotypically with Cl 3 VNCI in the triclinic space group P1̄. The crystals contain dimeric units which are formed via chlorine bridges. The VNI group is linear with an sp-hybridized nitrogen and a V-N triple bond, (angle VNI = 163°, V-N = 165 pm, N-I = 193 pm). A short contact distance of 307 pm between the I atom and a neighbouring Cl atom is observed.

n-Alkanol intercalation complexes of iron(III) oxide chloride FeOCl · a n-C x H x+1 OH (x = 1-18) are obtained from the amine intercalates by replacement reaction or by a "propping-open" procedure. The alkanol content is slightly variable with a = 0.54 in the alkanol richest phases and 0.46 after heating to 110 °C. In the alkanol richest phases the long chain alkanol molecules (x ≤ 12) form bilayers in the interlayer region of the FeOCl with the major part of each chain in all trans conformation and perpendicular to the layers of the host lattice. The complexes undergo a series of reversible phase transformations on heating. The arrangement of short chain alkanols (x ≤ 6) is less regular. At higher temperatures ( > 130 °C) condensation to FeO(OR) n Cl 1-n is observed. The alkoxylated derivatives are also capable of forming intercalation complexes.

N,N',N'-Triorganyl-N-trimethylsilylthioureas react with halogeno diorganyl boranes to yield the N,N',N'-organyl-thioureidoboranes 1-7 and isothioureidoboranes 8-15. 10-15 are intramolecularly associated. The compounds are characterized analytically and spectroscopically (NMR: 1 H, 13 C, HB; MS; IR).

In polycrystalline samples of the halogenoaluminates Me I AlCl 4 (Me I - Cu, Ag), CuAlBr 4 , C 6 H 6 · CUAlCl 4 and halogenogallates CuGaCl 4 , Me I GaBr 4 (Me I = Cu, Na, K, NH 4 , Rb, Cs, Ga), Me I GaI 4 (Me I = Cu, Cs), Me I Ga 2 Br 7 (Me I = K, NH 4 , Rb, Cs), CsGa 2 I 7 , the halogen, Me III , and Cu-NQR spectra were studied, partly as a function of temperature. Phase transformations are found in NH 4 GaBr 4 , CsGaBr 4 , and RbGa 2 Br 7 . The spectroscopic results are discussed and a charge distribution analysis is given, based on the Townes-Dailey theory. Symmetry properties of the solids are pointed out in connection with multiplicity and intensity ratios of the NQR spectra.

The photodegradation to CO 2 (photomineralization) of chlorinated alkanes, alkenes and aromatics adsorbed on silica gel was examined. In addition to CO2, Cl - and Cl 2 were determined. The degradation depends considerably on the activity of the surface and decreases in the order alkenes > alkanes > aromatics.

13 C and 1 H NMR spectra of ethyl and t-butyl substituted cobaltocenes dissolved in toluene, benzene and acetone are strongly dependent on concentration and temperature. With increasing metallocene concentration and decreasing temperature almost all 13 C and 1 H signals of the metallocenes as well as those of the solvents are shifted high field to a different degree. The additional shift is most pronounced for substituted aromatic ring carbons giving rise to a seriously disturbed signal ordering. Similar behavior is found for substituted vanadocenes and nickelocenes dissolved in toluene or THF. The effect is attributed to preferred mutual orientation of metallocene and solvent molecules thus inducing additional shifts in the metallocene themselves and in the solvent. From the results it is concluded that neither dipolar nor Fermi contact interaction can satisfactorily account for the effect. Instead it originates from susceptibility shifts which may not be ruled out by internal referencing and which are due to anisotropy and orientation of the molecules. For consequence quantitative comparison of paramagnetic NMR shifts from highly anisotropic molecules is only meaningful if concentrations are known. Measurement of magnetic moments may lead to errors.

Sodium and potassium tetrakis(trimethylsilyl)aluminate are synthesized by reaction of sodium or potassium with bis(trimethylsilyl)mercury and tris(trimethylsilyl)aluminium. Sodium and potassium tetrakis(trimethylsilyl)aluminate complexes, coordinated with diethylether, tetrahydrofurane or 1,2-dimethoxyethane are available by dissolving the unsolvated compounds in the ethers. The IR, Raman, 1 H and 13 C NMR spectra are discussed.

Bis(η 3 -allyl)- or bis ( η 3 -2-methylallyl )nickel react with hydrogensulfide at -78 °C to give in high yields the dimeric di-μ-hydrogensulfido-bis(η 3 -allyl)dinickel(II) (2) or di-μ-hydrogensulfido- bis(η 3 -2-methylallyl)dinickel(II) (2a), respectively, which decompose above 20 °C to give nickelsulfide and propene or isobutene. From bis(η 3 -allyl)nickel and deuterium sulfide, the di-μ-deuteriumsulfido-bis(η 3 -allyl)dinickel(II) was obtained. The high resolution 1 H NMR spectra reveal the existence of three stereoisomers of 2 or 2 a to which the structures c, d and e have been assigned. The high resolution 1 H NMR spectrum of η 3 -allyl-hydrogensulfido(trimethylphosphine)nickel(II) (3) at -100 °C is consistent with a square planar structure; above -100 °C an equilibration process between syn-, syn- and anti-, anti-protons occurs and above - 20 °C equilibration of syn- and anti-protons of the η 3 -allyl group is observed.

It is demonstrated that methyl loss from ionized homoadamantane (1) yields exclusively the 1-adamantyl cation (4); there is no experimental evidence for the formation of the secondary adamantyl cation (5). From both model calculations and the investigation of [4- 13 C]-homoadamantane (1a) and 1( 13 C-methyl)adamantane (2a) it is concluded, that 24% of the metastable homoadamantane cation radicals dissociate after one isomerization (1→2); the remaining 76% are able to undergo at least a second (degenerate) isomerization cycle (2→1→2) prior to methyl loss. 78% of metastable 1-methyl-adamantane cation radical, obtained upon direct ionization of the corresponding neutral hydrocarbon, dissociate directly, whereas the loss of methyl from the remaining 22% is preceded by an isomerization 2 →1 →2.

Pyrolysis mass spectrometry is shown to be a useful tool in the analysis of the protected intermediate deoxy oligonucleotides synthesized by the phosphotriester approach. Characteristic ions of the protected nucleic acid bases and terminal substituents appear in the mass fragmentation pattern which allows a rapid control of the attachment of the polynucleotide block in the chemical synthesis.

Four substituted tellurobenzoic acid-Te-esters (1 a-1 d) have been synthesized by a phase transfer technique from substituted benzoyl chlorides and sodium telluride.

From the methanolic extract from the roots of T. quadrangularis we isolated 14 alkaloids (1-14) and deduced their structures. All the alkaloids are of the ibogamine-type or im-mediately related to it; (20R)-20-hydroxyibogamine (5) was found for the first time as a natural product.

The structure elucidation of 27-p-cumaroxy ursolic acid is described.

Light induced isomerizations of the title compound have been studied. The thermal cis-trans isomerization 3→1 occurs via the tautomeric quinonephenylhydrazone (2) as shown by 1 H NMR, spectroscopy. The influence of solvent on the thermal cis-trans isomerization is discussed. 1 H NMR data of 1, 2 and 3 are given. Values of the tautomeric equilibrium 1⇋2 are determined for various solvents and different temperatures.

K 3 NO 3 and RbsNO 3 were prepared by solid state reaction of equimolar mixtures of K 2 O/KNO 2 and Rb20/RbN02, respectively. According to X-ray powder photographs their crystal structures are derived from the perovs-kite structure. K 3 NO 3 is isostructural with Na 3 NO 3 (a = 521.7 pm, Z = 1), Rb 3 NO 3 represents a tetragonally distorted variant with a = 770.5, c = 550.8 pm and Z = 2.

Unsymmetrically substituted dithiophosphinic acids RR'P(S)SH give planar metal chelates [RR'PS 2 ] 2 M 1 [M = Pd(II), Pt(II)]. It can be shown by comparison of their 31 P-{ 1 H} NMR spectra with those of symmetrically substituted compounds [R 2 PS 2 ]2M that in the synthesis of 1 equimolar mixtures of the cis and trans isomers are formed.

For the first time single crystals of trimolybdate were obtained through a slow trans-formation of the primary precipitate in a slightly acidified solution of rubidium molybdate at a temperature of 70 °C. A structural analysis of Rb 2 Mo 3 O 10 · H 2 O revealed that the anion forms a chain with a hexameric identity period built up from MoO 6 octahedra. Each Mo atom is bonded with two terminal oxygen atoms. The anion doesn't contain OH groups.

The title compound has been isolated from reaction of MOCl 5 and KOEt in ethanol. The presence of bridging alkoxy groups was proved by means of 1 H NMR spectra. Magnetic susceptibility and electronic spectra were measured, and the results are discussed in terms of octahedrally coordinated Mo(IV).

Ag 8 SnTe 6 has been synthesized by different methods. The Dielectric Absorption Spectra point to a silver ion conductivity.

The high-spin d 5 complexes M 2 Mn(1,2-C 6 H 4 (C≡C) 2 ) 2 (M = K, Na) are prepared in liquid ammonia according to equation (1). The magnetic moment and the position of the IR-active υC ≡ C of the potassium salt are discussed with respect to the structure of the solid compounds.

The cyclic phosphahydrazidinyl (5) was gen-erated and studied by ESR. The results are discussed in connection with the properties of other hydrazidinyl radicals.