Volume 36, Issue 2

The methanido-bis(aminophosphonium) salts 3a-d can easily be synthesized by CCl 4 -reaction of Ph 2 PCH 2 PPh 2 . Their structure is confirmed by 31 P{ 1 H} and 13 C{1H} NMR data. Dehydrohalogenation by NaH yields the methanidobis( phosphoranylamide/imide) 4 c. Several possible tautomers of 4c are discussed. With excess NaH the salts 3 a-d react to form the sodium-[methanido-bis(diphenylphosphoniumimides)] 5 a-d, sodium chelates of 4.

The hitherto unknown symmetrical diamino carbodiphosphoranes R 2 NPh 2 P = C = PPh 2 NR 2 (5 a-d (R = CH 3 , Et, nPr, nBu) are obtained in good yield by NaH dehydrohalogenation of the corresponding aminophosphonium salts 3 a-d can be prepared by aminolysis of C(PPh 2 Cl) 2 (1) or, more conveniently, directly in the three component reaction ditertiary phosphine/amine/CCl 4 ( 31 P{ 1 H} and 13 C{ 1 H} NMR).

The crystal structure of [MePh 3 P] 2 TiCl 6 was determined from X-ray diffraction data and refined to a residual index of R = 0.065. It crystallizes in the space group P2i/n with two formula units per unit cell; the cell dimensions are a - 921, b = 1314, c = 1648 pm and y - 100.87°. The TiCl 6 2- ion occupies an inversion center and has the shape of a slightly distorted octahedron with Ti-Cl distances between 233 and 235 pm.

Pure (TBA)[TcOI 4 ] is prepared from (TBA)[TcOCl 4 ] by ligand exchange reaction with Nal in acetone. The vibrational spectra indicate C 4v symmetry for the complex ion. On excitation with the 514.5 nm line of an Ar-laser a resonance Raman spectrum is obtained showing v(TcO) = 996 cm -1 and four of its overtones, symmetrically surrounded by groups of bands arising as well from the sums as from the differences of frequencies with the other fundamentals. In contrast to the ligand exchange reaction the reduction of Tc0 4 - with conc. HI yields products always contaminated with polyiodides. The extremely strong Raman scatterer (TBA)l 3 is detected by a characteristic doublet at 111 and 116 cm -1 and even small amounts of it cover the Raman spectrum of (TBA)[TcOI 4 ].

In the reaction of ketones RCOCH 3 (R = CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 , n-C 4 H 9 , i-C 4 H 9 , tert-C 4 H 9 ) with thallium(III) acetate in methanol, thallation at CH 3 or at a-C in R has been observed by NMR spectroscopy. J( 203/205 T1- 1 H) in RCOCH 2 X [X = Tl(OCOCH 3 ) 2 ] is nearly independent of R (ca. 1290 Hz), but in R′CHXCOCH 3 (R′ = H, CH 3 , C 2 H 5 ) it increases with increasing chain length. RCOCH 2 X and R′CHXCOCH 3 decompose to give the corresponding acetoxylated ketones, e.g. CH 3 COCH 2 OCOCH 3 . Analogous thallation products have been observed in the reaction of acetone and C 2 H 5 COCH 3 with thallium (III) iso-butyrate.

The crystal and molecular structure of (me 3 CN) 3 (me 3 A1O)Sn4 has been determined from three-dimensional X-ray data (4-circle diffractometer, R - 0.048). The crystals are mono-clinic, space group P2i/c, with cell dimensions a = 1017.4(5), b - 1488.5(7), c = 1748(1) pm, β-91.5(1)° and Z - 4. The molecules approach 3m point-symmetry and include a Sn 4 N 3 O-cage, the atoms occupying the corners of a distorted cube formed by two, differently sized, interpenetrating concentric tetrahedra of tin and nitrogen/oxygen atoms. The nitrogen atoms are attached to tert-butyl groups, whereas the oxygen atom of the cage acts as a base towards the aluminiumtrimethyl group. Typical bond distances and angles (mean values) are: Sn-N = 219.9, Sn-0 = 220.3 pm; N-Sn-N = 81.2°; N-Sn-0 = 79.0°; Sn-N-Sn = 98.8° and Sn-O-Sn -100.2°.

The compounds ;p-Me 2 P(X)-C 6 H 4 -P(X)Me 2 , X = O, S, Se, NPh undergo one-electron reduction at a mercury cathode or on reaction with solvated electrons in a K/18-crown-6/THF mixture. The radical anions formed are persistent and have been characterized by ESR. They may be described as complexes of the spin-bearing moiety p-Me 2 P-C 6 H 4 -PMe 2 · with the coordinated groups X.

2-Chlor-diazaborolidine, [CH 2 -N(CH 3 )] 2 BC1 (5) and N-silylated sulfur nitrogen compounds with sulfur in the oxidation state + 4 or + 6 react to form the boranes 7-11 which are thermally stable compounds. Reactions with other chlorboranes like [(CH 3 ) 2 N] 2 BC1, (6), (C 6 H 5 ) 2 BCl or C 6 H 5 BCl 2 as starting materials lead to less stable or unstable compounds. Spectroscopic data of the new compounds are given.

Dodecatungstosilicates free of crystal water were prepared for the first time by using tetraalkylammonium as cation. The crystal structure of the tetramethylammonium a-dodeeatungstosilicate [N(CH 3 ) 4 ] 4 SiW 12 O 40 (1) and tetrabutylammonium) β-dodecatungstosilicate, [N(C 4 H 9 ) 4 ] 4 SiWi 2040 (2) were solved by X-ray diffraction. (1) crystallizes tetragonal in the space group 14̅ with lattice parameters a = 14.642 Å; c= 12.706 Å; (2) orthorhombic, space group P2 1 2 1 2 1 with a = 29.277 Å, b = 22.181 Å and c = 15.381 Å. The differences between the two isomeric heteropolyanions are discussed, especially the distances and angles between the tungsten atoms. Comparison of characteristic differences in the vibrational spectra permits the identification of the isomeric anions.

From the reactions of (THF)M(CO) 5 (M = Cr, W) with 4-phenyl-1,2,3-thiadiazol, 4-methyl-5-carboxylic acid-1,2,3-thiadiazol, 4-methyl-5-carboxylic acid ethyl ester-1,2,3-thiadiazol and 4-methyl-1,2,3-selenadiazol, pentacarbonyl-complexes are obtained as air stable compounds. IR spectra of products of similar reactions with M = Mo provide some evidence of the formation of analogous complexes. The thiadiazol complexes are also accessible directly, by photochemical displacement of carbonmonoxid in THF from the parent carbonyl. The X-ray structures of pentacarbonyl-(4-phenyl-1,2,3-thiadiazol)-tungsten and pentacarbonyl-(4-methyl-1,2,3-selenadiazol)-chromium show the coordina-tion of the ligand to the pentacarbonyl-metal-fragment via the nitrogen in position 2.

The reactions between Hg(CN) 2 and HgX 2 in aqueous solutions of alkali halides MX (M = Na, K, Rb; X = CN, Cl, Br, I) lead to mixed cyanohalogenomercurates. Several compounds gained by crystallisation from aqueous solutions were characterized with X-ray, spectroscopic and thermal methods. The crystal structures of NaHg(CN) 2 Cl · H 2 O, KHg(CN) 2 Cl · H 2 O and RbHg(CN) 2 Cl · H 2 O have been determined by X-ray structure analysis with three-dimensional data. The compounds can be characterized as double salts, because the structures consist of Hg(CN) 2 -units and isolated M+ and Cl- ions. The relationship between these structures and those of the non-hydrated compounds are discussed.

The X-ray structure analysis of bis(chloromercuri)methane CH 2 (HgCl) 2 has been performed. CH 2 (HgCl) 2 crystallizes in Prnma with a = 713.7(4) pm, b - 643.6(4) pm, c = 1221.7(8) pm, Z = 4; the isotypic CH 2 (HgBr) 2 has a = 731.1(3) pm, b = 668.6(1) pm, c - 1260.1(4) pm. The CH 2 (HgCl) 2 molecules (site symmetry m) contain asymmetric CHg 2 entities with bond lengths R(C-Hg(l)) = 203.9(17) pm and R(C-Hg(2)) = 212.2(18) pm, respectively, whereas the two independent Hg-Cl bonds are almost the same (average (Hg-Cl) = 233.3(5) pm). The bond angles Hg-C-Hg (111.6(3)°) and C-Hg-Cl (average 177.8(5)°) fall into the expected range. The molecules are held together by two independent systems of short van der Waals contacts Cl →···Hg forming zig-zag chains along the 6-axis, and a wide variety of van der Waals interactions Cl →···Hg in planes parallel to (010). The arrangements in these planes produce maximum density molecular layers with coordination number six; including the molecules of two adjacent layers each molecule reaches a total coordination number of fourteen. Depending on the van der Waals radius assumed for mercury a packing coefficient 0.663 ≤ k ≤ 0.733 comparable to that of close-packing of spheres results.

The stable free radical 4,4,5,5-tetramethylimidazoline-1-oxyl-2-m-pyridyl-3-oxide has been prepared and used as a ligand in platinum(II), palladium(II) and copper(II) complexes. The magnetic moments and the EPR spectra of the complexes and the free radical have been investigated. The complexes show a considerable interaction between the nitroxyl radicals of the ligands.

The X-ray crystal and molecular structure of tetraethylammonium-tricarbonyl-(3,5-diphenylthiacyclohexadienyl-1-oxide)chromate has been determined. This organo-metallic anion can be nitrosylated to yield neutral [n 5 -C 5 H 3 (C 6 H 5 ) 2 SO](CO) 2 (NO)Cr. Further carbonyl displacement in this compound is achieved by treatment with pyridin or phosphanes in the presence of triethylamineoxide.

The molecular structure of (2,3-diazanorbornene)Fe 3 (CO) 9 consists of a triangular Fe 3 (CO) 9 group bound to the diazene unit. The seven-coordinated Fe(CO) 3 group forms two Fe-N bonds with lengths of 1.974 and 1.965 Å, each of the two six-coordinated Fe(CO) 3 groups has slightly shorter Fe-N-bonds of 1.898 and 1.903 Å. One Fe-Fe distance, 2.612Å, is longer than the two other ones, 2.572 and 2.582 Å, which are in the range of typical single bonds. The presence of seven-and six-coordinated iron carbonyl groups is also demonstrated by the Mössbauer spectrum showing signals with quadrupole splittings of 1.23 and 0.78, 0.62 ± 0.01 mm/s, respectively.

It is suggested that several basic properties of biological systems, such as muscular motions, active transport of energy, etc., may be described in terms of a dynamical model possessing metastable ferroelectric states. The model is based on the observation that confi-gurationally unstable anions, in particular O 2- , can lead to ferroelectric phase transitions. Due to the highly variable electronic polarizability of such ions a fourth-order potential is generated which can be the origin of three types of solitary excitations: elastic 'pulse' solitons, ferroelectric 'kink' (or domain-wall) solitons and periodic (coherent) solitary waves. Their possible relation to biological phenomena is discussed.

New complexes of Al(III), Fe(III), Co(III), Rh(III), In(III) and Zr(IV) with 1-phenyl- 3-methyl-4-trifluoroacetyl-pyrazolone-5, (HPMTFP), have been synthesized and characterized by means of elemental analyses, conductivity and magnetic moment measurements, proton NMR and infrared spectroscopy. It is concluded that the ligand, HPMTFP, reacts as a bidentate enol forming neutral metal chelates. The PMR spectra of chelates sufficiently soluble in deuterated NMR solvents were recorded and studied. The IR spectra are measured between 4000-200 cm-1 and assignments are proposed for the observed frequencies. The M-O stretching frequency follows the order: AI > Rh > Fe = Co = Zr > In.

Ynamines 2 bearing methyl or phenyl groups at their C/C triple bond react with tert-butylcyanoketene 1a to give the cyclobutenones 3 and/or the allene carboxamides 4. 3 and 4 are the products of two different [2 + 2] cycloaddition reactions. β-Silylated, β-germylated and β-stannylated ynamines 5 add the cyanoketenes 1 under "(aminoethynyl)metallation" to furnish the new enynamines 6. These compounds were characterized by IR and 1 H NMR spectroscopy and partly by mass spectrometry. The stannyl derivatives of 6 hydrolyze very easily to the corresponding acyl ynamines 7 and react with 4-nitrobenzoyl chloride to give the 1-(aminoethynyl)vinyl benzoates 8. The diazo compound 9 is formed by the interaction of tosyl azide on the enynamine 6 c, which is probably first hydrolyzed to 7a. N,N-Diethyl-N-(triphenylsilylethynyl)amine (5e) reacts with two molecules of tert-butylcyanoketene (1a) to give the allene derivative 10, probably via the corresponding enynamine 6 (R 1 = R 2 = Et, MR 3 3 = SiPh 3 , R 4 -tBu).

UV irradiation of aqueous solutions of 1,3-dimethyl-thymine with wavelength > 280 nm yields the eis-and trans-form of water addition product 1,3-dimethyl-6-hydroxy-dihydro-thymine (2/3).

The solvolysis of 25 differently substituted chloromethylated phenols was studied kinetically in methanol at 25 °C. A sharp decrease of the initial reaction rate with in-creasing concentrations of added acids can be explained by a very fast solvolysis of the phenolate anions in comparison with the undissociated compounds. The latter show strictly first order kinetics up to high conversions and the rate constants can be partly correlated with the Jaffé relation. Highly negative values for the reaction constants q = -5.4 and q = -6.2 for ortho-and para-chloromethylated compounds show, that the undissociated phenols react according to the S N l -mechanism. However, deviations are found for compounds with strongly electron attracting substituents, which may be partly caused by an intramolecular catalytic effect of the phenolic hydroxy group in the case of the ortho-isomers.

The X-ray structure of the 1:2 host-guest complex between 1,4,7,10,13,16-hexaoxa-cyclooctadecane (18-crown-6) and 2,4-dinitrophenylhydrazine is reported. Crystallo-graphy data are: space group P2 1 /c, a = 8.557(2), b = 16.745(6), c = 12.387(4) Å, β = 117.08(13)°, Z = 2, D m = 1.37 g · cm -3 , D c = 1.387 g · cm -3 , m.p. 414 K (decomp.). The present B is 0.11 for 1733 diffractometer data. In the complex, the two 2,4-dinitrophenylhydrazine molecules are located "above" and "below" the plane of the hexaether and related by an inversion centre. They interact with the macrocyclic host via N-H···0 hydrogen bonds, two of which are bifurcated. All the ether oxygens of the crown serve as hydrogen bond acceptors.

7-Dehydrocholesterol and ergosterol are oxidised by iodine and FeCl 3 under "physiologically similar" conditions to highly reactive alkylating species. These can be trapped by nucleophiles, such as 1-methylimidazole. The oxidation of the sterols to those alkylating species is discussed as a model-reaction for the first step in chemical carcinogenesis by endogene substrates.

The synthesis of 2,5-disubstituted 5,6-dihydro-1 H-pyrido[1,2-a]quinazoline-1,6-diones (3) by reacting monosubstituted bis 2,4,6-trichlorophenyl malonates (1) with 3-aryl-3,4- dihydro-2-methyl-4-quinazolinones (2) is described. Allylation of the pyridoquinazoline 3c with allylbromide afforded the corresponding 3-allyloxy derivative 4. Certain generalizations of the cleavage processes of this series in the MS are reported.

The trisaccharide, 3,4-di-O-(a-L-rhamnopyranosyl)-D-galactose was synthesized using benzyl 2,6-di-O-benzyl-β-D-galactopyranoside as starting compound. Its acetobromo derivative was coupled with 4′,7-di-O-benzyl-kaempferol. The structure of the synthetic kaempferol trioside was characterised by different spectroscopic methods (UV, IR, 1 H, 13 C NMR and MS). Chromatographic and mass spectrometric comparison of the synthetic product with ascaside precluded their identity.

A new flavonolignan, isosilychristin (1), has been isolated from the fruits of Silybum marianum L. Gaertn. Its structure and configuration is elucidated by spectroscopic methods.

Tri-tert-butyl-cyclotriphosphane is obtained by the dehalogenation of 1,3-diiodo-1,2,3-tri-tert-butyl-triphosphane with lithiumhydride. This reaction represents a so far unknown type of ring-closure leading to cyclotriphosphanes, which corresponds to the classical synthesis of cyclopropanes starting from 1,3-dichloropropanes.

The interaction of SbF 5 with B(OTeF 5 ) 3 yields SbF 4 OTeF 5 and SbF 3 (OTeF 5 ) 2 .

Cesiumhydroxide has been prepared by the reaction of CsOH · H 2 O with CSNH 2 in super-critical ammonia. Thermochemical data for CsOH are given in the range from 100 to 640 K. The x-ray investigation of the compound above 497.5 K shows a sodium chloride type of structure with a = 6,427 (5) Å at 503 K. The lattice constants for the rhombic modification at 298 K are a = 4,350 (3) Å, b = 11,99 (1) Å and c = 4,516 (3) Å. The cell contains four formula units. The structure is of an anti-NaOH type.

The observation of a new type of ESR spectrum in the course of redox experiments on a platinum uracil "blue" compound is reported. Some characteristic features of the ESR and optical absorption spectra are described. A tentative analysis of the ESR spectrum is pre-sented, based on the assumption of localized states.

Cannabidiol 3 has been synthesized under high pressure conditions (7-8 kbar, 150 °C) from Olivetol 1 and trans-p-Menthadien-(2,8)-ol-(1) 2 with 41% yield. The influence of different solvents on the yield has been studied.

2-Hydroxy-6-methoxy-3,5-dimethyl-1,4- benzoquinone was found in the blackish potato culture solution of Phoma wasabiae.

The relative magnitude of the nitrogen hyperfine splitting constants of sulfonamidyls and carboxamidyls is rationalized in terms of the results of ab initio MO calculations using the "double zeta" basis set of Roos and Siegbahn.