Volume 40, Issue 12

The reaction of Mo(CO) 6 with Ph 2 Te 2 in toluene yields a black amorphous precipitate of Mo„(TePh) 3n-3 (CO) 6 (n ~ 4) as the main product besides smaller amounts of Mo 2 (CO) 8 (TePh) 2 which can be obtained from the solution as black crystals. They crystallize in the monoclinic space group C2/c with the lattice parameters a = 1872.0 pm, b = 751.9 pm, c = 1741.6 pm, β = 103.14°, Z = 4. In the dinuclear complexes of symmetry Q the Mo atoms are bridged by two TePhligands. The octahedral coordination of each Mo atom is completed by four CO groups. Mo -Mo interaction is indicated by a distance of Mo-Mo = 311.4 pm and a small bond angle Mo - Te - Mo = 69.14°

The new compound Ba 2 Sb 3 crystallizes in the monoclinic system, space group P2 1 /c (No. 14) with the lattice constants a = 693.4(3) pm, b = 1345.3(6) pm, c = 1581.7(6) pm, β = 90.25(15)°. The compound is isotypic to the Sr 2 Sb 3 structure with discrete Sb 6 8- chain anions

As a major product from the reaction of PNP-nitrite [P = P(C 6 H 5 ) 3 ] with elementary sulfur or a PNP-polysulfide (PNP) 2 S 12 in acetone under anaerobic conditions PNP-perthionitrite (PNPnitrosodisulfide) PNP-SSNO has been isolated. VIS/UV-spectra point to a thionitrate or perthionitrate as a precursor. The structures of PNP-SSNO and of the product obtained on treating the perthionitrite with triphenylphosphane in acetonitrile, PNP -SNO (PNP-monothionitrite, PNP-nitrososulfide), have been elucidated through X-ray diffraction and independently from new chemical and NMRspectrometric arguments. PNP-SSN O crystallizes in the orthorhombic space group P ben with a = 11.843(3), b = 16.647(5), c = 15.556(4) Å , PNP -SNO in the triclinic group P1̄ with a = 10.525(3), b = 17.196(5), c = 9.451(3) Å , a = 95.22(3), β = 92.32(3), γ = 91.65(3)°.

Alkaline-earth dicyanoargentates M[Ag(CN) 2 ] 2 • 2H 2 O (M = Ca. Sr) were synthesized by reaction of M(ClO 4 ) 2 with K[Ag(CN) 2 ] and subsequent fractionated crystallization. The colourless, light-sensitive crystals are orthorhombic, space group Pbcm, with a = 8.435(1) Å, b - 6.3985(6) Å , c = 18.584(2) Å , Z = 4 (M = Ca), and a = 8.0032(8) Å, b = 6.8688(5) Å, c = 18.870(1) Å , Z = 4 (M = Sr). A structural model derived from Direct Methods was refined to R = 0.064 and R = 0.044. rsp. The structure of the two isotypic compounds comprises layers of [Ag(CN) 2 ]“ dumb-bells, arranged in such a way, that trigonal prisms of nitrogen are formed. These prisms are occupied by the alkaline-earth ions. Three oxygen atoms from neighbouring water molecules complete a tricapped trigonal prism around Ca 2+ and Sr 2+

K 3 HAs 2 O 5 -6H 2 O 1 has been crystallised from aqueous solution and its crystal structure established by X-ray analysis. 1 contains isolated hydrogendiarsenite anions HAs 2 O 5 3- , composed of two corner-sharing ψ -AsO 3 -tetrahedra. The anion displays the semi-eclipsed conformation in which the lone-pairs on the As atoms take up a syn-position with respect to an As-O bond on the opposite As atom. As a result the pyramidal coordination geometry of the As atoms is considerably distorted. The HAs 2 O 5 3- anions in the crystal lattice are linked via O - H ··· O hydrogen bonds into infinite chains parallel to the b-axis, which are surrounded by water molecules of crystallisation

A new, improved method of synthesis for the cyclothiazeno complex AsPh 4 [WCl 4 (N 3 S 2 )] consists of the reaction of Na 2 WO 4 with molten trithiazyl chloride (NSCl) 3 followed by treatment with AsPh 4 Cl in CH 2 C 12 . Through the reaction with silver azide suspended in CH 2 C 12 in the presence of moisture, black crystalline (AsPh 4 ) 2 [W(N 3 S 2 )(O)(N 3 ) 2 ] 2 is obtained. Its IR spectrum and its crystal structure are reported. Crystal data: triclinic, space group P1̄, Z = 1, a - 1018.3, b = 1107.8, c = 1379.1 pm; a = 91.11°, β = 106.74°, γ = 113.91°. Structure determination with 3219 observed reflexions, R = 0.061. The structure consists of AsPh 4 + cations arranged to form (AsPh 4 + ) 2 pairs and of dimeric anions [W(N 3 S 2 )(O)(N 3 ) 2 ] 2⊖ in which the tungsten atom s are members of planar cyclothiazeno rings WN 3 S 2 with WN bond lengths of 186 and 222 pm. The oxygen atoms are in positions trans to the longer of these bonds. One of the N atoms of each cyclothiazeno ring is involved in the dimerization resulting in a centrosymmetric W 2 N 2 ring. The azido groups are situated above and below the ring system and complete the coordination number of six for the W atoms with WN distances of 208 and 212 pm

The pyridine complexes of cyclo-thiazeno vanadium dichloride, [VCl 2 (N 3 S 2 )py] and [VCl 2 (N 3 S 2 )(py) 2 ] were synthesized by reactions of polymeric VCl 2 (N 3 S 2 ) with varying amounts of pyridine in CH 2 Cl 2 . The compounds were characterized by their IR spectra as well as by their 51 V NM R spectra. The crystal structure of [VCl 2 (N 3 S 2 )(C 5 H 5 N)] was determined by means of X-ray diffraction (1582 independent observed reflexions, R = 0.031). Crystal data: orthorhombic, space group Pnma, a = 1372, b - 2261, c - 1068 pm, Z = 12. In the lattice there are two monomeric, crystallographically independent molecules [VCl 2 (N 3 S 2 )(C 5 H 5 N)], which differ only slightly. The vanadium atoms have a trigonal bipyramidal coordination with the N atom of the pyridine molecule and one chlorine atom in apical positions, and with one chlorine atom and the N atoms of the cyclo-thiazeno ligand in equatorial positions. The VN bond lengths of the planar VN 3 S 2 ring of 174 pm correspond to double bonds

By reaction of CS 2 with maleonitrile in the presence of sodium-ethanolate in ethanol Na 2 S 2 C 4 N 2 is obtained. It reacts with Ba(NCS) 2 · 3 H 2 O in a metathesis reaction to give BaS 2 C 4 N 2 ·3 H 2 O. The space group of the barium salt is C 2/c with Z = 8. The structure consists of Ba 2+ and [S 2 C -C(CN) 2 ] 2- ions, and crystal water. Barium has a distorted tricapped trigonal prismatic coordination: four O, three N and two S atoms. There are considerable deviations from planarity for the [S 2 C 4 N 2 ] 2- anion due to packing effects

The sulfidefluorides LnSF with Ln = Er, Yb, Lu undergo a high pressure transformation from the β-YSF- to a PbFCl-type structure. The structures involved and a proposed reaction mechanism are explained in terms of a topological description

The phases CaTa 2 O 6 and CaTa 4 O 11 were prepared at high temperature; electron micrographs of their well known structures were taken by high resolution transmission electron m icroscopy. A comparison with simulated images using different values of crystal thickness and defocus shows the validity of the described computation method

Electrocrystallization of BEDT -TTF in THF with tetrabutylammonium nitrate as supporting electrolyte leads to the deposition of at least three different phases. The a-phase (C 10 H 8 S 8 ) 3 (NO 3 ) 2 , M t = 1277.98, crystallizes in the monoclinic space group P2 1 /n. The structure of this solid was solved: a = 5.890(2), b = 31.125(10), c = 12.915(6) Ä , β = 103.73(3)°, V = 2300 Å 3, Z - 2, D x = 1.84 gem -3 , MoKf α λ = 0.7107 Å , μ = 11.2 cm -1 , F(000) = 1300, room temperature, R = 0.057 for 1888 observed independent reflections. Sheets of BEDT-TTF radical cations with short intermolecular S···S contacts (>3.315(4) Å ) are separated by anion layers. Two more BEDT-TTF nitrates have been characterized by their unit cell data. Results of temperature dependent electrical conductivity and thermopower measurements on crystals of the a-phase are presented. They are metallic down to about 30 K

Crystals of the β-phases of (BEDT-TTF) 2 Br-I-Br (1) and (BEDT-TTF) 2 I-I - Br (2) have been isolated by electrocrystallization. The solids can be obtained using different tetrabutylammonium trihalides containing iodine and bromine as supporting electrolytes. Cyclovoltam metric results show clearly that the trihalide anions are involved in the oxidation reactions near the anode which finally lead to the crystals. 1 C 20 H 16 Br 2 IS 16 , Mr = 1056.01, and 2 C 20 H 16 BrI 2 S 16 , M t = 1103.01 are isom orphous, crystallizing in the triclinic space group P1̄, with Z = 1. Unit cell parameters for 1: a = 6.5979(6) A , b = 8.998(1) Å, c = 15.138(3) Å , a = 94.03(1)°, β = 95.13(1), γ = 110.28(1), V = 834.7 Å and for 2: α = 6.606(2) Å , b = 9.047(6) A , c = 15.229(6) Å, α = 94.28(2)°, β = 95.34(2), v = 109.92(2), V = 846.5 Å 3 . The different sizes of the Br2I - and Brl 2 - counterions lead to different intra- and interstack S -S contacts in the solids thus influencing the physical properties. An additional Br 2 I - phase with a modulation of the above-described structure could be found. Some relevant physical properties of 1 and 2 are reported

Ruthenium trichloride, obtained from its hydrate with thionyl chloride, reacts with excess trichloronitrom ethane yielding polymer [Ru(NO)Cl 3 ]; by addition of triphenylmethylphosphonium chloride in dichlorom ethane (PPh 3 Me) 2 [Ru(NO)Cl 4 ] 2 · 2 CH 2 Cl 2 is obtained, the IR spectrum of which is reported and assigned. Its crystal structure was determined with X-ray diffraction data (6404 independent observed reflexions, R = 0.068). Crystal data at -90 °C: a = 1145, b = 1591, c = 1406 pm, β = 96,0°, Z = 2, space group P2 1 /C. The structure consists of PPh 3 Me ⊕ cations, centrosymmetric anions [Ru(NO)Cl 4 ] 2 2⊖ nearly fulfilling C 2h symmetry, and CH 2 Cl 2 molecules. In the anions the Ru atoms are linked via chloro bridges; the nitrosyl groups occupy axial positions with bond distances RuN of 175 and NO of 113 pm, bond angle RuNO 172.7°.

On reacting PH-functional m ethylenebisphosphanes (iPr)HPCH 2 PH 2 (1) and RHPCH 2 PR 2 (R = CH 2 Ph) with excess Fe 2 (CO) 9 P -C -P-bond cleavage occurs. As a result β-phosphido bridged clusters e.g. Fe 3 (CO) 8 (μ 2 -PRCH 2 PR 2 )(μ 3 -PR)(μ 2 -H) (11) and Fe 4 (μ 4 -P) spiro com pounds with naked phosphorus atoms Fe 4 (CO) 13 (μ 4 -P)(μ 2 -PRCH 2 PR 2 ) (10) or Fe 4 (CO) 14 (μ 4 -P)(μ 2 -P(/Pr)Me) (6) are obtained. Uptake of one molecule of CO by 11 and ametallation of one CH 2 Ph substituent within the PR 2 donor group yields 12. Compound 10 • CH 2 C 12 crystallizes in the space group C2 1 /c with a = 36.357(7), b = 10.752(2), c = 22.879(5) Å , β - 112.45(1)°, Z = 8 {R = 0.050 for 5213 reflections). Both the phosphido atoms of the μ 2 - PRCH 2 PR 2 group and the μ 4 -P atom span the Fe1 -Fe2 bond of a Fe2(CO) 6 species while only the μ 4 -P atom spans the Fe3 -Fe4 bond of a (CO) 4 FeFe(CO) 3 fragment. In addition, the Fe(CO) 3 part of the latter unit is bonded to the tertiary P atom of the μ 2 -PRCH 2 PR 2 group. Compounds 11 and 12 cocrystallize in the space group P1 with a = 11.541(2), b = 17.739(2), c - 19.284(2) Å , a = 78.01(1), β = 78.68(1), y = 90.36(1)°, Z = 2 of each (R = 0.051 for 10234 reflections). A(CO) 3 Fe -Fe(CO)2-Fe(CO) 3 core having an acute Fe11-Fe12 -Fe13 angle of 77.46(3)° at the Fe(CO) 2 group is found for 11. The Fe12 - Fe13 bond is bridged by both the ,μ 3 -PR group and the hydride ligand. The Fe 11 -Fe 13 contact is spanned by the μ 3 -PR ligand and the ,μ 2 -P atom of the ,m 2- PRCH 2 PR 2 species. Three Fe(CO) 3 groups are bridged by the μ 3 -PR ligand in 12. Only two of the Fe(CO) 3 groups appear to be directly bonded. Fe21 -Fe23 is bridged by the μ 2 -P atom of the ,μ 2 -PRCH 2PRCHPh ligand while Fe22 -Fe23 displays a novel Fe22 - P - C -Fe23 linkage

Using 293 K diffractometer intensity data, the structures of [H 3 N(CH 2 ) 3 NH 3 ]TeCl 6 and [H 3 N(CH 2 ) 3 NH 3 ]SnCl 6 have been determined by single crystal X-ray technique and refined to a final of 0.027 and 0,029, respectively. The yellow crystals of the tellurate are orthorhombic (space group Pnma) with a = 22.952(2), b = 7.5414(4), c - 7.801(1) Å and Z = 4. This structure contains distorted TeCl 6 2- octahedra (distances Te - Cl min. 2.426(1), max. 2.672(1) Å ) with approximate 2mm point symmetry. In contrast, the SnCl 6 2- ion in the second title com pound is octahedral with only small deviations from m 3m symmetry (distances Sn -Cl mean: 2.438(3) Ä ). The colourless crystals of this tin com pound are orthorhombic (space group Pnma) with a - 17.6082(9), b = 7.1809(3), c = 10.190(1) Å and Z = 4. Considering the TeX 6 2- (X = Cl, Br, I) salts known to date, a distorted species is an exception, although a distortion is predicted by the VSEPR theory. The results agree with the rules for the appearance of a static stereochemical effect of the lone pair electrons in the TeX 6 2- species

Treatment of the cationic complexes [(η 5 -C 5 Me 5 )M(CO) 3 ] ⊕ BF 4 ⊖ (M = Fe, Ru) (1a , b) with the bulky lithium silyl phosphide LiP(Ar')(SiMe 3 ) (Ar' = 2,4,6-tri-fert-butylphenyl) (2) leads to the phosphaalkenyl complexes (η 5 -C 5 Me 5 )(CO) 2 M - C(OSiMe 3 ) = P ~ Ar' (4a, b). The presence of C = P double bonds in 4a, b was ascertained by 13 C- and 31 P NMR spectra. The geometry at the C = P bond was also deduced from the analysis o f the NMR spectra ( 1 H , 13 C, 31 P)

4.5-Dimethyl-4'.5'-ethylenedithiolotetrathiafulvalene (DIMET) was obtained by reacting 4.5- ethylenedithiolo-1.3-dithioliumtetrafluoroborate with 4.5-dimethyl- 1.3-dithiolium-tetrafluoroborate in the presence of diisopropylethylamine or triethylamine. Electrocrystallization of this donor in different solvents like dichloromethane or tetrahydrofurane (THF) and with varying supporting electrolytes, like tetrabutylammonium hexafluorophosphate, triiodide, nitrate, perrhenate or perchlorate, results in a large number of well crystallizing compounds. The crystal and molecular structure of one of the isolated solids was elucidated by X-ray methods. (C 10 )H 10 S 6 ) 2 CIO 4 x C 4 H 8 O, Mr = 816.66, is triclinic, P1̄ , a = 6.731(5), b - 7.632(3), c = 33.32(3) Å , α = 96.53(5), β = 92.99(6), γ = 103.13(5)°, V - 1650.7 Å 3 , Z = 2, d c = 1.64 gem -3 , final R w = 0.077 for 1844 observed independent reflections. Sheets of cations with an average charge of 1/2+ are separated by sheets of anions and THF solvent molecules. Intermolecular S···S contacts result in two-dimensional physical properties. Electrical conductivity and thermopower measurements indicate two broad phase transitions at around 200 K and 80 K

The reaction of o-phenylene-bis(dichlorophosphane) (1) [2] with anhydrous Lil in benzene gives o-phenylene-bis(diiodophosphane) (2). In the presence of water the reaction leads to the bicyclus 3 [1], Electrolysis of 1 with a mercury-pool at a potential of -800 mV in a 1.2-dichloroethane/ 0.1 Mtetrabutylammonium tetrafluoroborate solution gives 1.2.5.6-tetraphospha- 3.4-7.8-dibenzo-2.6-dichloro-bicyclo[3.3.0]octane (4). The reduction of 3, either by magnesium in THF or by electrolysis in 1.2-DCE/0.1 M TBATFB solution at a potential of -1 V yields the oligomer (o-C 6 H 4 P 2 ) 5

The preparation of K 8 [Co 4 S 3 (SO)(CN) 12 ] • 4 H 2 O (by cyanolysis of “cobalt sulfide”) and its properties (vibrational, UV/VIS and ESCA spectra, magnetic and thermogravimetric data, and crystal structure) are reported. The formation of a “SO " ligand through air oxidation is discussed with regard to the promoting effect of Co in the CoMoS phase of the hydrodesulfurization (HDS) catalyst

The application of v. Smoluchowski’s theory concerning diffusion controlled reactions to the O 2 quenching of fluorescent dyes adsorbed on surfaces predicts that the viscosity of the medium in front of the surface has a considerable influence on the fluorescence intensity. We have studied pyrene adsorbed on polystyrene grains and got the experimental result that changing the medium in front of the surface from a gas phase to water is not accompanied by a change of the quenching behaviour. This result is clearly in contrast to the theoretical predictions. In our opinion the discrepancy may be explained by the special conditions the dye molecule at the surface experiences. We assume that the pyrene molecules are situated in some small groves of the polystyrene grains and that the properties of the medium within those groves are responsible for fluorescence quenching by O 2 . The medium in front of the surface cannot get into the groves

Alkaline hexacyanoferrate(III) oxidation (Decker oxidation) of the title compound 9 yields the isomeric pyridones 10 and 11 in nearly equal amounts whereas the pyridinium salt 12 gives only the carboxylic acid 10 under this conditions. From this result it is concluded that 9 is not an indermediate during the oxidation of 12. Spectroscopic data of 10 and 11 are compared for structural determination. A HPLC-method is described concerning quantitative analysis of a mixture of 10 and 11 via the corresponding 4-bromophenacylester derivatives

Several new isoxazole derivatives were prepared from the newly synthesized 4-arylazo-3,5- diaminoisoxazole

The reactions between the OH radical and fumaric acid, maleic acid, malic acid and succinic acid were studied using pulse radiolysis techniques. The rates of reaction, the absorption spectra of the resultant free radicals and the rates of disappearance of those radicals were determined as a function of pH over virtually the entire pH range (pH 2-14)

From the cell material of Cystobacter fuscus (Myxobacterales) the cerebroside 1-O-β-D-galactopyranosyl- N-(2R-hydroxy-15-methylpalmitoyl)-17-methylsphinga-4E,8E-dienin (main component) and three related compounds could be isolated, the structure elucidation of which is being reported here

Reaction of harmidine/harmaline with BrCN has afforded mono- and di-bromo derivatives I and II respectively indicating the substitution of bromine at the α-carbon of imine through its enamine tautomer

In the presence of alkali and LAuCl one or two -NH - groups of a purine or pyrimidine base can be transformed into - N(AuL)- groups giving stable and soluble compounds containing one or two two-coordinated gold(I) nuclei; mononuclear LAu - Q' or binuclear LAu - Q - AuL with a monodentate Q' - or an exobidentate O -- ligand, resp. (Q'H = adenine, guanine, theobromine, theophylline, azaguanine or cytosine; QH 2 - thymine or uracyl; L = triphenylphosphine)

The heterocycles 3 to 6 are formed in a one-pot procedure by reacting trifluoromethyl phosphorus diiodide F 3 CPI 2 with tin dichloride SnCl 2 in the presence of the corresponding 1,3-dienes. The reactions proceed via [2+4] cycloaddition of the diphosphene intermediate F 3 CP = PCF 3 (1) as suggested by the high yields obtained (50 to 100%) and the formation of the cyclic tetraphosphane (F 3 CP) 4 (2) as the only by-product. Cycloreversion occurs at moderate temperatures as demonstrated by the reaction of 6 with 2,3-dimethylbutadiene to give 3 and cyclohexadiene. The products have been characterized by NMR and mass spectra

By reaction of zinc chloride and zinc bromide with hexamethylenetetramine in water/methanol crystals of the adducts ZnCl 2 • C 6 H 12 N 4 and ZnBr 2 • C 6 H 12 N 4 , resp. were obtained. The compounds are isotypic, they crystallize in the orthorhombic space group P2 1 am (non-standard setting of space group Pmc2 1 , No. 26), Z = 2. The lattice parameters of the zinc chloride adduct are a = 1168.0(4), b = 685.7(4), and c = 601.1(4) pm, of the zinc bromide adduct a - 1188.9(6), b = 721.5(5), and c = 602.3(4) pm. The adducts are polymeric, they form parallel chains in the crystal. The zinc atoms are bonded to two halogen atoms and, via nitrogen atoms, to two hexamethylenetetramine molecules, which act as bidentate ligands. The coordination of the zinc atoms is approximately tetrahedral

The colourless com pound NaLiS has been prepared and its structure determined by single crystal X-ray diffraction techniques. The very hygroscopic NaLiS crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a = 402.6(1), c = 649.5(2) pm. The structure was solved from 720 counter reflections (216 symmetry independent reflections) by differential Fourier syntheses. Refining gives a least squares residue of 0.024. The anti-PbFCl-type structure is characterized by layers of LiS 4/4 -tetrahedra connected by their edges in two dimensions and 2 interspersed layers of sodium

The colourless compound RbNaO has been prepared as described earlier [1 ], but single crystals were not yet available at that time. N ow its crystal structure was determined by X-ray diffraction techniques. The very hygroscopic RbNaO crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a - 406.8(1), c = 649.4(1) pm. The structure was solved from 1031 counter reflections (375 symmetry independent reflections) by using differential Fourier syntheses. Refining gives a least squares residue o f 0.086. The structure forms an am/-PbFCl-type geom etry with c-centered squares of sodium interspersed by antiparallel ordered pairs of R b-O

At 9.4 T the I03Rh relaxation times (T ,) of unsym metrical organorhodium com pounds of the type LR h(7r-ligand) 2 are in the order of seconds, and relaxation is dominated by the Chemical Shift Anisotropy mechanism. In symmetrical complexes like (acac)3Rh (7), T, of 103Rh is considerably longer and dominated by the Spin Rotation mechanism. Through this effect, together with selective polarisation transfer via the Rh olefin-proton spin-spin couplings at high magnetic fields, a significantly improved detection of the insensitive Rh nucleus results