Volume 56, Issue 8

β-Ytterbium borate (β-YbBO 3 ) was synthesized under high-pressure in a Walker-type multianvil apparatus at 2.2 GPa and 1400 °C. The title-compound crystallizes in the trigonal calcite structure, space group R3̄̄c. Single crystal X-ray data yielded a = 492.1(2), c = 1630.5(9) pm, wR2 = 0.0344 for 165 F 2 values and 11 variable parameters. Within the trigonal planar BO 3 groups the B-O distance is 137.8(4) pm. The ytterbium atoms have a slightly distorted octahedral oxygen coordination (Yb-O: 224.4(2) pm)

The bifunctional 2,3-dihydro-2-methoxyethylimino-l,3-dimethylimidazole (C 8 H 15 N 3 O , 10) is obtained from the reaction of methoxyethyl tosylate (7) and 2,3-dihydro-2-imino-1,3- dimethylimidazole (8) followed by deprotonation in good yield. 10 reacts with {(COD)RhCl}2 (COD = 1,5-cyclooctadiene) to give the imine complex (C 8 H 15 N 3 O)Rh(COD)Cl (11), which is converted into the chelate complex [(C 8 H 15 N 3 O)Rh(COD)]BF 4 (12) on treatment with AgBF 4 . The imine complex (C 8 H 15 N 3 O) 2 PdCl 2 (13) is formed through the reaction of 10 with (PhCN) 2 PdCl 2 . The X-ray structures of 11, 13 and 2 C 8 H 15 N 3 O · H 2 PdCl 4 (15) are reported

The four ternary gallium(III) chalcogenide halides GaEX with E = S, Se and X = Cl, Br can be prepared a) from the binary gallium(III) chalcogenides Ga 2 E 3 and halides Ga 2 X 6 , b) from gallium(I) tetrahalogallates(III) GafGaX 4 ] and the chalcogen E, and c) from gallium metal and the dichalcogen dihalides E 2 X 2 . The new method c) was shown to be the most convenient preparation. The products are readily soluble in pyridine to give trinuclear molecular complexes [GaEX·Py] 3 which are not volatile without decomposition, but can be purified by crystallization. The structures have been determined by single crystal X-ray diffraction techniques. The two chlorides are isostructural and show twisted tub-form six-membered ring molecules with the pyridine donors in axial positions. The two bromides are also isostructural, but with the pyridine ligands in two axial and one equatorial positions

Preparation, crystal structure and magnetic properties of a 3,5-dimethylpyrazolate bridged binuclear copper(II) complex [Cu 2 (L 1 )(3,5 prz)] (L 1 = 1,3-Bis(2-hydroxy-1-napthylideneamino) propan-2-ol) (1) are reported. Variable-temperature magnetic susceptibility measurements for a powdered sample of the complex were carried out in the temperature range 5 - 350 K and analysed to obtain values of the parameter J in the exchange Hamiltonian H = -2JS 1 ·S 2 . In the dicopper(II) complex [Cu 2 (L 2 )(3,5 prz)], (L 2 = l,3-Bis(2-hydroxy-5-chlorosalicylideneamino) propan-2-ol) (2) reported recently the antiferromagnetic interaction is much less than that of 1 (-27 = 440 cm -1 ), as result which is difficult to explain in terms of structural factors on the basis of widely accepted criteria. The differences in the magnetic behaviour now have been rationalized using the “ligand orbital complementary” concept

A water-soluble gold cluster with a core of 32 to 36 gold atoms was prepared by NaBH 4 reduction of the AuCN complex of n-butyl-bis (5-morpholinocarbonyl-2-furyl)-phosphine and characterized by its mass spectrum. The chromatographic behavior, ligand exchange and binding to actin were studied

The anion of 2,4-dicyano glutaconic acid diethyl ester, [NCC(COOEt)CHC(COOEt)CN] - (1 - ), as an α,μ;-dinitrile with a three atom spacer is a highly variable ligand capable of binding in a monodentate η 1 -fashion, in a bidentate chelate fashion, and as a μ 2 -bridging entity. TripodFe(1) 2 , 2, [tripod = CH 3 C(CH 2 PPh 2 ) 3 ] contains one chelating ligand 1 - and one terminally coordinated ligand 1 - - . Variable temperature NMR spectroscopy shows, that, while the structure is static at 193 K, dynamic exchange of the donor functions of chelating and terminally bonded ligands occurs at higher temperature. TripodFe(1) 2 , 2, is obtained from a 1:1:2 mixture of tripod, Fe(II) aq (BF 4 ) 2 , and Na1-2H 2 O . With a stoichiometry 1:1:1 of these ingredients and an additional naif equivalent of sodium cyanide, the dinuclear compound [tripodFe{μ-NCC(COOEt)CHC(COOEt)CN} 2 {μ-CN}Fetripod]BF 4 , 3 BF 4 , is obtained. The structure of 3 + shows a helical arrangement of the ligands 1 - around the Fe···Fe axis which is a consequence of the incomensurability of the bridging ligands 1 - and μ-CN. The two iron centers in 3BF 4 differ by their coordination to the carbon or to the nitrogen terminus of the bridging cyano group. This difference is reflected by the NMR spectra, Mössbauer spectra and cyclovoltammograms

The structures of the compounds [Rh(bpy) 2 (py)(Cl)](ClO 4 ) 2 (2 (ClO 4 ) 2 ) and [Rh(phen) 2 (py)- (Cl)](ClO 4 ) 2 (7 -(ClO 4 ) 2 ) were determined by single-crystal X-ray diffraction. Both complexes show a six-coordinate rhodium atom with two bpy or phen ligands in the cis configuration. The Rh-Cl distances are 2.334(3) and 2.323(2) Å, respectively. The bond angles N-Rh-Cl formed with the axially-positioned nitrogen atom are 174.4(2) and 173.8(2)°. The oxidation of aquo complexes, prepared from the corresponding rhodium chloride complexes, by two equivalents of Ce(IV) in 60% HCIO 4 solution yields the corresponding mono-oxo products. All complexes have been identified and characterized by elemental analyses, IR, and 1 H NMR data

The compounds (Hg 3 )(PO 4 )Cl, (Hg 3 )(AsO 4 )Cl and (Hg 3 )(AsO 4 )Br have been prepared under hydrothermal conditions at 200 °C, starting from stoichiometric mixtures of the corresponding mercury halides and mercury phosphates or arsenates, respectively. The formula (Hg 3 )(AsO 4 )Cl is identical with that of the mineral kuznetsovite. All compounds are isotypic and crystallize with four formula units in the space group P2 1 3 [(Hg 3 )(PO 4 )Cl: a = 8.2912(5) Å; (Hg 3 )(AsO 4 )Cl: a = 8.3983(6) Å; (Hg 3 )(AsO 4 )Br: a = 8.4611(5) Å]. All crystal structures have been refined from single crystal diffractometer data sets under consideration of merohedral twinning according to a diagonal mirror plane as twin element. The structures comprise of equilateral mercury triangles with mean distances d̄(Hg-Hg) = 2.659 Å, which are bonded to halogen and oxygen atoms of nearly perfect PO 4 or ASO 4 tetrahedra, respectively

[(THF) 2 LiCl 2 VCl 2 (THF) 2 ] (1) and [Li(THF) 4 ][OMoCl 4 (THF)] (2) can be prepared by the reactions of VCI 3 with LiCl in THF and of Li(H)P t Bu with OM0 CI 4 in THF, respectively. 1 and 2 were characterized by IR spectroscopy, MS spectrometry (2) and X-ray crystallography. 1 can be obtained in two modifications depending on the temperature of crystallization. At -30 °C a triclinic form, 1a, was isolated from THF solution with one unique molecule per asymmetric unit. However, at 20 °C, 1b crystallized in the monoclinic space group P2/c. It possesses four independent molecules per asymmetric unit. According to the structure analyses 1 consists of a dinuclear complex with a planar LiCl 2 V four-membered ring while 2 consists of seperate ions [Li(THF) 4 ] + and [OMoCl 4 (THF)] -

The new disulfonylamines R -N (SO 2 Me) 2 , where R = cyclopropyl (1), cyclobutyl (2), cyclopentyl (3) or cyclohexyl (4), were prepared according to an established one-step procedure (condensation of RNH 2 with two equivalents of MeSO 2 Cl, NaH as basic auxiliary). Whereas the structure determination for 1 was marred by severe disorder, compounds 2 -4 have been characterized by low-temperature X-ray diffraction (2: monoclinic, space group P2 1 Z ' = 2, pseudo-P2 1 /c packing; 3: triclinic, P1̄, Z' - 1; 4: orthorhombic, Pbca, Z ' = 1). The four independent molecules display puckered carbocycles, whereby the electronegative (MeSO 2 ) 2 N substituent occupies an equatorial position, leading to short intramolecular C - H···O contacts (2: angles of ring pucker φ ≈ 30-33°; 3: envelope conformation, φ ≈ 40°; 4: chair conformation, φ 1 ≈ φ 2 51°). In accordance with known congener structures, the C(sp 3 )-N (S) 2 moieties feature trigonal-planar N configurations and unusually long C -N bonds (ranges for 2-4: C -N 148.8-150.8 pm, S -N 166.6-168.9 pm, S -N -S 118.3-119.3°). The three crystal packings are governed by a plethora of weak intermolecular hydrogen bonds C(sp 3 )-H···O , and a thorough survey of these interactions reveals that the inductively activated methyl groups are distinctly more efficient hydrogen bond donors than the methine and methylene ring groups. In each structure, the principal hydrogen bonds create layer substructures parallel to a unit cell face, which are cross-linked by the remaining C -H···O contacts to form three-dimensional networks

A series of new bis[N-(1-OH-2,6-di-tert-butylphenyl)salicylaldiminato]cobalt(II) complexes possessing one or two HO- and CH 3 O - substituents on the salicylaldehyde moiety were prepared, and their spectroscopic properties as well as their oxidation with PbO 2 were examined. ESR data indicate that oxidation of the complexes produces stable phenoxyl radicals. All phenoxyl radicals have similar g-values and hyperfine coupling constants, which are influenced very little by the substituents and by coordination. The experimental observations indicate that the Co(L ·x ) 2 radicals are ligand-localized and that there is no notable contribution from the metal d-orbitals to the values of the g-factors. Satellite peaks from the 13 C nuclei in the aromatic ring were also observed. The ESR spectra of some of the complexes showed partial conversion of primary radicals to secondary paramagnetic species exhibiting interaction with 59 Co(I = 7/2) and 14 N nuclei

Ten guaianolides, including three previously unreported natural products, were isolated from the aerial parts of Cichorium intybus (Asteraceae), more commonly known as chicory. Two of the new compounds ( 8 and 9) were analogues of lactupicrin and 11/β,13-dihydrolactupicrin, respectively, with the C-15 oxidized to the aldehyde state. The third new natural product, which we have called mtybulide A (10), is an isomer of lactucin with the lactone closed to the C-8 oxygen rather than the C-6

New plant growth regulators, named chloroisosulochrin, chloroisosulochrin dehydrate and pestheic acid, have been isolated from the culture filtrate of Pestalotiopsis theae grown on a Raulin-Thom medium. Their structures have been established by spectroscopic and chemical methods. The biological activities of these compounds have been examined using bioassay methods with lettuce and rice seedlings

The title compounds were prepared by building up the triazole ring at the anomeric position via the glycosyl azides 5 a,b. The anomeric configurations of these nucleosides were assigned by using 1 H, 13 C and NOESY NMR spectroscopy. The synthesized nucleosides were evaluated against HIV-1 and HBV

A number of alkyl(aryl)chloro-N,N-dialkylaminophosphanes RP(Cl)NR 1 R 2 (1a-o ) were synthesized starting from alkyl(aryl)dichlorophosphanes RPCl 2 and amines by a convenient procedure with nearly quantitative yields. The reactivity of alkyl(aryl)-N,N-dialkylamino(halogeno) phosphanes RP(Hal)NR 1 R 2 (Hal = Cl, I) with cyclopentadienyl, bis(cyclopentadienyl), indenyl, bis(indenyl) and fluorenyl carbanions has been investigated. The new aminocyclopentadienylphosphanes R„Cp(R)PNR 1 R 2 2a-f and 3a-c (R„Cp = Ind, Flu, Cp 2 CMe 2 , Ind 2 CEt 2 , Ind 2 (CH 2 ) 2 ) were characterized by spectroscopic techniques and elemental analyses. Flu(t-Bu)PN(H)t-Bu (2f) was characterized by X-ray diffraction analysis

The oxidation or consecutive ammoxidation reaction of benzyl alcohol with solid ammonium permanganate was studied. The first oxidation step leads to the formation of benzaldehyde, ammonia, and MnO 2 . The MnO 2 is present in the system in a colloidal form which facilitates the reaction between aldehyde and ammonia, and this latter reaction then yields benzonitrile. All these products are formed in a heterogeneous system under relatively mild conditions. The yield of benzaldehyde has an optimum at room temperature and increases with increasing reaction time. At higher temperature (e.g. 80 °C) benzonitrile is formed together with minor amounts of benzyl benzoate

Cyclization of 2-hydrazino-5,6-dimethyl-3H-thieno[2,3-d]pyrimidin-4-one (1) with acetic acid gave 3,6,7-trimethyl-l,2,4-triazolo[3,4-a]thieno[2,3-d] pyrimidin-5-one (5) whose Dimroth rearrangement gave 2,6,7-trimethyl-l,2,4-triazolo[3,4-a]thieno[2,3-d]pyrimidin-5-one (11). Alternatively, 5 was obtained from the dehydrogenative cyclization of acetaldehyde 5,6- dimethyl-4-3H-oxo-thieno[2,3-d]pyrimidin-2-yl hydrazone (7). Reaction of 1 and 2 with a number of sugars gave the respective hydrazones 19 and 20. Those of the D-glucose exist in the cyclic pyranosyl structure in addition to minor amounts of the acyclic structure. Dehydrogenative cyclization of the sugar hydrazones gave the respective fused tricyclic compounds 25 and 26

The ethyl acetate soluble part of a methanolic extract of the marine green alga Codium iyengarii, collected from the Karachi coast of the Arabian Sea, afforded four new derivatives of glycerol named : codioside A,B,C,D (1-4), a new derivative of frans-phytol named codioester (5) and rrans-phytol (6). The structures of 1 -5 were elucidated with the aid of acid hydrolysis, methylation, GC-MS, and spectroscopy. The structure of 1 was confirmed through the HMBC NMR technique and the structures of compounds 2 -4 were based on the assignments made for 1

Dihydroquinol derivative 1, quinol glucopyranoside 2 and quinol derivative 3 have been isolated from the ethyl acetate soluble fraction of Ajuga parviflora and their structures have been elucidated through spectroscopic studies as methyl 2-[2,2-dimethyl-6-oxo-7-dihydro-1,3- benzodioxol-3(6H)-yl]aceate (1), 2-hydroxy-4β-methyl-4a-(β-D-glucopyranoside)-2,5-cyclohexadien- 1-one (2) and (4-oxo-2,5-cyclohexadien-1-yl)acetic acid (3). The known quinol 4 has also been isolated for the first time from this species