Volume 49, Issue 9

The reaction of tellurium with WCl 6 in the presence of bromine in a sealed evacuated ampoule in the temperature range from 220 to 150 °C yields dark blue monoclinic crystals of β-Te 4 (WCl 6 ) 2 , space group P2 1 /c, lattice constants a = 664,3(2), b = 1273,2(3), c = 1233,6(3) pm, ß - 94,13(3)°. The structure is built of square planar Te 4 2+ cations and slightly distorted octahedral WCl 6 - anions and shows a close relationship to the previously reported triclinic α-form, which was obtained in the absence of bromine. The difference between the two structures lies in a different packing of the ions

The title compound Zn(NH 3 ) 4 (ClO 4 ) 2 crystallizes in the space group F4̄3m with a = 10.240(1) Å. The crystal structure consists of tetrahedral Zn(NH 3 ) 4 cations and two nonequivalent ClO 4 anions with crystallographic T d symmetry. The complex ions constitute an arrangement which is known from the Zintl phase MgAgAs. The Zn(NH 3 ) 4 cations are ccp packed with perchlorate anions in octahedral and tetrahedral voids. Whereas the ClO 4 ions centered at tetrahedral holes do not interact with the other lattice components, the perchlorate ions in the octahedral voids are connected with the ammine ligands by a hydrogen bonded three-dimensional network involving all their N, H, and O atoms. The repeating unit of this network is a N 4 O 4 (μ-H) 12 cube with N-H = 1.19(2) Å and O···H = 1.98(2)Å . Raman and IR spectra were recorded between 150 and 4000 cm -1 . All the expected internal modes of the complex ions could be detected and assigned. The crystallographically different ClO 4 anions have nearly the same vibrational spectra, only a slight splitting of two IR modes is observed

Reaction of Ba 3 N 2 with CeN in the stoichiometric ratio 1:3 at 850 °C under an atmosphere of N 2 followed by quenching yields air and moisture sensitive BaCeN 2 . The product crystallizes isotypically to β-RbScO 2 with the anti-TiP type structure in the hexagonal space group P6 3 /mmc with a = 365.06(2), c = 1266.03(3) pm, Z = 2. The structure was determined using X-ray and neutron powder diffraction data. In the structure the Ba 2+ cations occupy trigonal prismatic holes with distances Ba-N = 288(1) pm while the Ce atoms are in octahedral positions with distances C e -N = 242.4(8) pm

Ternary phases in the system TaS 2 -MoS 2 have been obtained by thermal reactions at 1050 °C of binary layered disulfides and NH 4 Cl as promotor. Ternary phases Ta 1-x Mo x S 2 exist in the range 0.5 ≤ x ≤ 0.9. In the range of 0.25 ≤ x ≤ 0.55 the reactions are quantitative and the phase-compositions are determined by the amounts of the starting materials. For x < 0 .2 1 T-TaS 2 and for x > 0.60 2 Hc-MoS 2 are contaminating the resulting ternary phases. Ternary phases have been characterized by X-ray powder diffraction and are indexed rhombohedrally on the basis of a 3 R-structure with metals in trigonal-prismatic coordination. The phases Ta 1-x Mo x S 2 with 0.25 ≤ x ≤ 0.55 show a reversible transition of higher order associated with a change in the electrical conductivity mechanism. Below 420 K the phases show semiconductivity while above 460 K metallic conductivity is observed

Single crystals of sodium formate dihydrate, NaHCO 2 ·2H 2 O, have been prepared from aqueous solutions of sodium formate, NaHCO 2 , via the trihydrate, NaHCO 2 -3H 2 O. They are orthorhombic, space group Cmca, with a = 7.070(4), b = 14.534(2), c = 8.706(2) Å and Z = 8. The structure, including the hydrogen atoms, was refined to R = 0.054, R w = 0.065 for 479 unique reflections with I > 3 σ (I). It comprises buckled layers formed by NaO 6 octahedra which are edge- and corner-sharing. The octahedral coordination of the sodium ions is achieved by two oxygen atoms from two different end-on bonded formate ions and four water oxygen atoms. The O···H distances show clearly that strong hydrogen bonds are not involved in the bonding system

The d 6 -Co(III)-species [tripodCo-(ortho-(X)(Y)C 6 H 4 )] + (X, Y = O, S, tripod = CH 3 C(CH 2 PPh 2 ) 3 ) 1 are reversibly reduced to the neutral d 7 -Co(II)-compounds [tripodCo-(ortho-(X)(Y)C 6 H 4 )] (X, Y = O, S) 2. Both species show fivefold coordination of cobalt with coordination polyhedra in between the limits of the square pyramid and the trigonal bipyramid respectively. The low-spin d 7 -species 2 give clearly resolved ESR-spectra revealing the coexistence of two geometric isomers above -80 °C, with only one isomer persistent at temperatures around 100 K. As an analogous d 5 -system [benzyltripodFe-(ortho-(S)(S)C 6 H 4 )] + 3 (benzyltripod = C 6 H 5 CH 2 C(CH 2 PPh 2 ) 3 ) has been obtained from [benzyltripodFe(NCCH 3 ) 3 ] 2+ and C 6 H 6 S 2 . Alternatively complexes of this type, e.g. [tripodFe-(ortho-(S)(S)C 6 H 4 )] + 4, may be prepared from Fe(H 2 O) 6 (BF 4 ) 2 /tripod/C 6 H 6 S 2 when the reaction mixture is activated by acidification with HBF 4 . The geometry of the d 5 -species 3 and 4 is close to a trigonal bipyramid

A series of complexes with anions of N-[1,2:3,4-di-O-isopropylidene-6-deoxy-α-D-galactopvranos-6-yl]-α-aminoacids has been obtained and characterized by spectroscopic data: 1-4 (R' = 6-deoxy-galactopyranosyl), (η 5 -C 5 Me 5 )(Cl) 5, 6 (M = Rh, Ir), (η 5 -C 5 Me 5 )M(CH 3 SCH 2 CH 2 CH(CO 2 )NHR') 7,8 (M = Rh, Ir), M(NHR 'CHRCO 2 ) 2 9-16 (M = Cu, Pd), (η 2 -C 2 H 4 )(Cl)Pt(NHR'CHRCO 2 ) 17-20, Cl 2 M(CH 3 SCH 2 CH 2 CH(CO 2 R)NHR) 21-24 (M = Pd, Pt), Cl 2 M(NHR'CHRCO 2 Me) 2 25-31 (M = Pd, Pt). The structures of 3 (R = CH 2 CH 2 SMe), 4 (R = CH 2 Ph), 7 (M = Ir) and 21 (M = Pd, R = H) have been determined by X-ray diffraction

The vibrational spectra of the title compounds have been recorded and interpreted based on the symmetry D ooh of the isolated linear anions [MX 2 ] n- (M = Cu, Ag, Zn, Cd. Hg; X = P, As, Sb). The calculated stretching force constants are: f(M II -P) = 1.89 {M II = Zn}, 1.66 {Cd}, 1.83 {Hg} Ncm -1 and f(Cu-X ) = 1.27 {X = P}, 0.99 {Sb} and f(Ag-As ) = 0.93 Ncm -1 respectively. These are compared with those of the isoelectronic molecules M II Y 2 and [M I Y 2 ] - in relation to charge effects (M II = Zn, Cd, Hg; M I = Cu, Ag; Y = Cl, Br)

An efficient synthesis of diarylallenylidene pentacarbonyl chromium and tungsten com­plexes is presented. Irradiation of M(CO) 6 in THF affords (CO) s M[THF], Substitution of the THF ligand by diarylpropargylalcoholate and subsequent desoxygenation with COCF gives the title compounds in good yield. (The structure of diphenylallenylidene pentacarbonyl chromium has been determined by X-ray structure analysis

Ethylcycloarsathiane (C 2 H 5 AsS) n crystallizes as a crown-shaped cyclotetramer 1 from a chloroform/pyridine solution. 1 H and 13 C NMR studies indicate the presence of two major oligomers in CHC 13 solution in an approximately 1:1 ratio. Reaction of 1 with AgCF 3 SO 3 yields [Ag{cyclo-(C 2 H 5 AsS) 4 } 2 ]CF 3 SO 3 (2) in which the silver (I) cation exhibits a distorted quadratic-antiprismatic coordination geometry with four shorter (2.716(7), 2.767(5) Å) and four longer (3.218(6), 3.328(9) Å) Ag-S distances. The tetraethylcyclotetraarsathiane ligand exhibits a K 1 S coordination mode in the complex [cyclo-(C 2 HsAsS) 4 ]·2SbBr 3 (3) with the sulphur atom adopting an axial positon in a ψ-trigonal bipyramidal antimony coordination polyhedron

On reaction of disecondary methylenebisphosphanes H (R)P-CH2-P(R)H and H(tBu)P-CH 2 -P(R)H(R = Ph, 2,4,6-R' 3 C 6 H 2 , R' = Me, Et, iPr, tBu) with excess Fe 2 (CO) 9 , Ru 3 (CO) 12 and Os 3 (CO) 12 the hydrido clusters M 3 (CO) 9 (μ 2 -H )[μ 2 -P(R, tBu)-CH 2 -P(R,tBu)H] (M = Fe, Ru, Os) (3a -3j) are formed in addition to bimetallic phosphido com plexes (5a -5g) and clusters (4a - 4f) with [μ 2 -P(R,tBu)] 2 CH 2 bridges. At higher temperatures cleavage of the P-C-P skeleton in 3a, 3b, 3d and 3h is accompanied by activation of the terminal C-H bonds of ortho-substituents R' (Et, iPr, tBu), phosphinidene clusters (8a, 8b, 8d and 8e) containing 2,3-dihydrobenzo[b]phosphole ligands being formed. Cluster com pounds Fe 3 (CO) 9 [μ 3 -P(R, tBu)][MeP(H)R] (7a - 7c) with secondary phosphane ligands could be identified as intermediate products. The X-ray structural analysis of Fe 3 (CO) 8 (μ 2 -H) 2 L(L = 1,3,3-trirnethyl-6,8-di-tert-butyl-2,3-dihydrobenzo[b]phosphole) (8e) shows a trigonal pyramidal Fe 3 P skeleton with the 2,3-dihydrobenzo[b]phosphole ligand in axial position. Metal-assisted fragmentation of the methylenebisphosphanes H(R )P-CH 2 -P(R)H(1f, 1g) with less bulky aromatic substituents (R = Ph, 2,4,6-Me 3 C 6 H 2 ) affords bis-μ 3 -phosphinidene clusters Fe 3 (CO) 9 (μ 3 -PR)(μ 3 -PR') 11e (R = R' = 2,4,6-Me 3 C 6 H 2 ) or 11f (R' = Ph, R = Me) and the phosphaalkene cluster Fe 3 (CO) 9 (μ 3 -PPh)(μ 3 , η 2 -P(Ph)=CH 2 ) (13b), respectively. If 1g is treated with Fe 2 (CO) 9 in an 1:2 molar ratio at elevated temperatures cleavage of the P-C-P skeleton leads to 14, a bimetallic complex with different phosphido bridges [μ 2 -P(R )H and μ 2 -P(R)Me]

[FeL(MeOH)Cl] 2 (L = N-(2-hydroxyphenyl)salicylaldimine) was synthesized and its crystal structure determined, [C 27 H 20 N 2 O 5 Cl 2 Fe 2 ], monoclinic, space group P2 1 /c, a = 9.528(1), b = 7.684(1), c = 18.365(2) Å, β = 109.83(1)°, V = 1264.8 Å 3 , Z = 2. Two identical [FeL(MeOH)Cl] fragments, related by an inversion centre, are combined by the two bridging O atoms, to form a binuclear unit. The iron(III) centers are separated by 3.163(2) Å and weakly antiferromagnetically coupled (J = -8 .0 (1 ) cm -1 ), which follows from temperature - dependent magnetic susceptibility measurements in the range 4.2 to 288 K. The effective magnetic moment per iron(III) is μ eff = 7.4 μ B at 288 K

The title compound is available from the reaction of labile gold(I) chloride complexes and an excess of the ligand ( t Bu 3 P), or from the NaBH 4 reduction of ( t Bu 3 P)AuCl. It forms dark red cubic crystals, [a = 14.297(1) Å at -56 °C, space group P2 1 3, Z = 4], with isolated chloride anions and [( t Bu 3 P) 2 Au] + cations of C 3 symmetry, with linear two-coordinate gold centers

The reactions of the N.N'-dialkyl/aryl-ethylenediamines l a - e with equimolar amounts of tetrachlorosilane give the monocyclic aminosilanes 2 a - e in good yields. With two equivalents of the diamines 1 only one spirobicyclic compound, l,4,6,9-tetrabenzyl-l,4,6,9-tetraaza-5-silaspiro[ 4.4]nonane, 4e, can be prepared. It is only via an independent double deprotonation of the diamines that the spirobicyclic ethyl- and isopropyl derivatives 4a and 4b are also becoming available. A ll compounds have been characterized by multi-NMR and mass spectrometry. In three cases (2d, 2e and 4e), the crystal and molecular structures have been determined by X-ray diffraction analysis. A planar silaimidazolidine ring system has been confirmed for the phenyl substituted species 2d, while in the corresponding benzyl substituted homologue 2 e both nitrogen atoms are pyramidal and lead to ring puckering. The silicon atom in 4 e shows a strongly distorted tetrahedral coordination. The endocyclic angle N 1 - Si - N2 = 92.8(1)° is nearly orthogonal, and the angle between the planes defined by the silicon and the two nitrogen atoms of the five-membered rings is 81.4(1)°.

Crystals of KCoPO 4 were obtained by growth in a gel of tetramethoxysilane/water at 64 °C. The hexagonal crystals have space group P6 3 , a = 18.206(1), c = 8.5135(8) [Å], V = 2443.8(4) [Å 3 ]. Z = 24. The structure was solved by single crystal X-ray diffraction methods. The structure is isotypic with α-KZnPO 4 . It comprises an ordered three dimensional network of alternating CoO 4 and PO 4 tetrahedra. which has rings of six tetrahedra in the xy plane. These rings form tunnels in the [001] direction, where the potassium ions are located. Upon heating, the compound undergoes a phase transition at about 565 °C; on cooling, the phase transition occurs at 449 °C, where it transforms into another structure which is yet unknown. This indicates that the hexagonal structure is a metastable phase

By electrochemical oxidation of [B 6 H 6 ] 2- in the presence of nitrite ions and of the base DBU in dichlorom ethane solution the μ-nitroso-bis(pentahydrohexaborate) [B 6 H 5 (NO)B 6 H 5 ] 3- ion is formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of the Cs salt has been determined from single crystal X-ray diffraction analysis. Cs 3 [B 6 H 5 (NO)B 6 H 5 ] is orthorhombic, space group Pnma with a = 16.2303(13), b = 12.245(6), c = 25.444(2) Å. The unit cell contains three crystallographically independent anions with nearly C 2v symmetry but differently distorted B 6 cages

By reaction of [B 6 H 6 ] 2- with N-(chloromethyl)phthalimide in dichloromethane the intermediate phthalimidomethylhexahydro-closo-hexaborate(1-), [B 6 H 6 (CH 2 (NC 8 O 2 H 4 )] - , is formed which with an excess of hydrazine reacts to give am inomethylhexahydro-closo-hexaborate(1-). The crystal structures of Cs[Bf,H 6 (CH 2 NH 2 )] and K[B 6 H 6 (CH 2 NH 2 )] have been determined by single crystal X -ray diffraction analysis. They are monoclinic, space group C2/m with a = 11.123(6), b = 6.8441(11), c = 12.810(7) Å, β = 124.032(5)° for Cs[B 6 H 6 (CH 2 NH 2 )] and with a = 10.767(2), b = 6.6255(6), c = 12.2648(14) Å, β = 123.880(10")° for K [B 6 H 6 (CH 2 NH 2 )]. The 11 B NMR spectrum is consistent with a monohetero substituted octahedral B 6 cage with local C 4v symmetry. In the 13 C NMR spectrum of Cs[B 6 H 6 (CH 2 NH 2 )] a quartet at 32.7 ppm with 1 J(C,B) 65 Hz is observed. The IR and Ram an spectra exhibit characteristic CH, NH, BH and B 6 vibrations

The crystal structure of MnSO 3 H 2 O , space group P2 1 /n, Z = 4. D x = 2.842(2) g · cm -3 , a = 4.843(3), b = 12.807(6), c = 5.762(4) Å, β = 90.39(4)° has been determined. MnSO 3 ·H 2 O crystallizes in a hitherto unknown structure type, which is closely related to that of orthorhombic MnSeO 3· D 2 O. Coordination of Mn is octahedral involving O atom s from one water moleculeo and four different sulfite ions. The Mn-O distances range from 2.136(3) to 2.285(3)Å . The S-O distances are 1.552(3), 1.556(3) and 1.482(3)!Å. The MnO 6 octahedra form layers parallel (010) by sharing four equatorial vertices. The layers are connected by weak hydrogen bonds and shifted laterally by 0.7 Å from the arrangement with m symmetry, found in MnSeO 3 ·D 2 O. Due to this shift, the water molecule is asymmetrically bonded, as shown by both the O-H···O distances (2.967(4)-3.834(5)Å) and the OD stretching modes (2554 and 2576 cm -1 ) of partly deuterated samples

High temperature reactions of BaCO 3 /MnO/Er 2 O 3 (3:1:1) led to single crystals of Ba 3 ErMn 2 O 9 . The product shows the structure of the hexagonal precious metal oxides Ba 3 LnRu 2 O 9 , but crystallizes with orthorhombic symmetry, space group C 12 2v -Cmc2 1 , a = 5.823 Å, b - 10.099 Å, c = 14.409 Å; Z = 4. The crystal structure is characterized by ErO 6 octahedra, Mn 2 O 9 face shared double octahedra and Ba 2+ within cuboctahedral and anticuboctahedral coordination by O 2- , respectively. In contrast to precious metal oxides the Mn-Mn distances inside the Mn 2 O 9 double octahedra are elongated

Single crystals of the title com pounds were obtained by high pressure synthesis in a modified Belt type apparatus. The compounds crystallize in the monoclinic system (space group P2 1 ) with a = 8.732(2), b = 5.468(1), c = 8.841(2) Å, β = 90.61(2)° for TlZnPO 4 and a = 8.921(3), b = 5.631(1), c = 8.958(3) Å, β = 91.03(2)° for TlZnAsO 4 , Z = 4. The structures were refined from diffractom eter data to R = 0.072, R w = 0.050 for 3700 (TlZnPO 4 ) and to R = 0.093, R w = 0.067 for 3943 (TlZnAsO 4 ) independent absorption corrected reflections. The compounds are isotypic and belong to the “stuffed derivatives" of the Icmm structure type with a (ZnXO 4 ) - network of alternating corner linked ZnO 4 and XO 4 tetrahedra (X = P, As) forming channels of six-membered rings in the direction of the a axis. These cavities contain two crystallographically independent Tl cations in an irregular coordination by eight nearest oxygen atoms

The structure of the orange pigment from the lichen Squamarina cartilaginea has been elucidated by NMR spectroscopical methods as 2,6.8-trihvdroxy-3-methyl-7-ethyl-1.4-naph­thoquinone

Haemophaein, a metabolite of the lichen Phyllopsora haemophaea has been structurally elucidated as 1-(2',2'-dihydroxyheptyl)-3,6-dihydroxy-8-(2"-oxoheptyl)-dibenzofuran-2- carboxylic acid-9,2'-lactone

From the marine brown macroalga Fucus virsoides J. AG. (Fucales, Phaeophyceae), a mixture of triacylglycerols 1 -3, fucosterol 4, a mixture of galactosyldiacylglycerols 5-8 and fucoxanthin 9 have been isolated. Normal phase column flash chromatography was effective for the isolation of the marine compounds. FAB-MS, CI-MS spectrometry, 1 H NMR, 13 C NMR, 1 H- 1 H COSY and 1 H- 13 C COSY experiments were useful in providing informations for their structure elucidation

The kinetics of the hydrogenation of (Z)-(a)-N-acetamidocinnamic acid catalysed by Rh complexes of the optically active layer-phosphines 2-7 was examined. The turnover was calculated from the consumption of hydrogen during the reaction. The catalytic activities of the layer-phosphines 2-7, which depend on the position of the borneoxy substituents on the phenyl rings, were compared with the catalytic activity of the parent ligand dppe 1