Volume 52, Issue 11

While TiCl 4 and Na 2 S 4 react in in the presence of PPh 4 Cl in dichloromethane to yield (PPh 4 ) 2 [TiSCl 4 ]·2CH 2 Cl 2 , we obtained [Ti 4 O 6 (OSMe 2 ) 12 ]Cl 4· 5Me 2 SO · 1/2H 2 O (1) from the same reactants in dimethylsulfoxide. Compound 1 is only stable in the presence of dimethylsulfoxide. The crystal structure determination at 153 K shows the presence of cations having an adamantane-like Ti 4 O 6 4+ skeleton with three Me 2 SO molecules coordinated to each Ti atom via their O atoms. Crystal data: monoclinic, P 2 1 /n, Z = 4, a = 1096.9, b = 3097, c = 2342.7 pm, β = 93.90° (at -120 °C; R = 0.087 % for 4098 reflections). In an attempt to produce the same compound only from TiCl 4 and Me 2 SO, [TiO(OSMe 2 ) 5 ]Cl 2 was obtained. Its cation has a rather short Ti=O bond (164.8 pm) and a distorted octahedral coordination of the titanium atom. The crystals are triclinic, P1̄, Z = 2, R = 0.050 for 2063 reflections measured at 153 K.

The reactions of benzo-18-crown-6 with MeX 2 (Me = Cd, Hg; X = Cl. Br), and of dibenzo-18-crown-6 with Hg(CN) 2 afford the compounds [Me(benzo-18-crown-6)X 2 ] (1-4) and [Hg(dibenzo-18-crown-6)(CN) 2 (5), resp., the crystal structures of which were determined. They consist of isolated neutral molecules, the crystalline Cd complexes and 5 contain one molecule of water of crystallization per formula unit, which however is not coordinated to the metal atom. The metal atoms are coordinated by the six O atoms of the ligands and the two halide atoms, or the two CN groups for 5, resp., the coordination being more unsymmetrical for the benzo than for the dibenzo ligand.

The compound Na 7 [Na⊂{(Mo V 2 O 4 ) 3 (μ 2 -OH) 3 H(PhPO 3 ) 4 } 2 ] · 2N 2 H 4 · 26 H 2 O (formulation with respect to the aggregate in the crystal) has been synthesized and character­ized by single-crystal X-ray structure analysis (which alone does not allow the determi­nation of the formula), UV/Vis/NIR/IR, 31 P{ 1 H}, 1 H and 23 Na NMR spectroscopy as well as magnetic susceptibility measurements. The compound is formed under similar conditions as (NH 2 Me 2 ) 6 [H 2 ⊂(Mo V 2 O 4 ) 6 O 4 (μ 2 -C)H) 12 (Mo VI O 3 ) 4 ].Correspondingly, both cluster frame­ works are built up by the same {(Mo V 2 O 4 ) 3 (μ 2 -OH) 3 } 3+ units.

The crystal structure of bromine nitrate BrONO 2 has been determined on a single crystal with MoKα radiation at -83°C. The structure is orthorhombic, space group P2 1 2 1 2 1 , Z = 4, and the cell dimensions are a = 403.2(2), b = 684.9(4), c = 1201.4(5) pm. An intermolecular Br.....O contact leads to the formation of chains within the crystal. Attempts to synthesize a bromine(III)-nitrate by oxidizing CF 3 Br and CF 3 Br with ClONO 2 were not successful.

The new macrocyclic dithiocyanatocuprate(I) complex [NH 4 (18-crown-6){Cu(NCS) 2 }] has been prepared using a direct method of interaction and characterized by X-ray crystallography (orthorhombic, space group Cmc2 1 , with a = 12.453(2), b = 21.650(4), c = 8.151(2) Å, V = 2197.6(8) Å 3 , Z = 4 , R1 (F) = 0.054; wR2(F 2 ) = 0.141 for 972 unique reflections with I > 2σ(I) and R1(F) = 0.082; w/?2(F 2 ) = 0.210 for all 1098 unique reflections). The lattice comprises complex cations [NH 4 (18-crown-6)] + and infinite polymeric anions [Cu(NCS) 2 ] - of a one-dimensional zig-zag structure. The copper atoms adopt three-fold coordination [CuN 2 S] (Cu-N 1,89( 1), 1,90( 1) Å; Cu-S 2.278(4) Å).

The synthesis and properties of donor-stabilized trisethinylborane compounds 1 - 3 (donor = pyridine, tetrahydrothiophene, tetrahydrofuran) and of the tris(trimethylsilylethinyl)boranediethylether adduct 4 are reported. Attempts to obtain donor-free trisorganylethinylboranes have failed. 11 B NMR data of 1 - 4 and the X-ray structure analysis of 1 and 3 reveal that the boron atoms are four-coordinated. The B-C bonds in 1 are somewhat longer and the C≡C bonds shorter than in diborylacetylenes.

(Benzyl)triphenylphosphonium bromide, [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + Br - (CH 2 Cl 2 ) (1) has been prepared by the reaction of triphenylphosphine with benzylbromide and its structure determined. The colorless crystals are triclinic, space group P1̄, Z = 2, a = 976.0(3), b = 1069.0(3), c = 1226.1(4) pm, α = 94.13(3), β = 104.70(3), γ = 100.14(3)°. The lattice contains Br - anions and [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + cations. [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ]Br 3 (2) has been obtained by treating compound 1 with equimolar quantities of elemental bromine in methylene chloride solution. The red crystals of 2 are monoclinic, space group P2 1 /c, Z = 4, a = 917.9(2), b = 1022.6(2), c = 2573.6(5) pm, β = 99.11(2)°, and comprise[C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + cations and linear, slightly asymmetrical Br 3 - anions with bromine-bromine distances of 246.19(11) and 263.69(11) pm.

The interaction between Ni(II) and amino acids with an aromatic residue (such as tyrosine and tryptophan) and either 9 substituted bases or nucleosides has been studied. Ternary derivatives obtained in solid state were characterised by, among other techniques, elemental analysis, thermogravimetry, electronic and infrared spectroscopy. The following complexes have been obtained: 1: [Ni (tyr) 2 (9EtAde) 2 ] × 4H 2 O; 2: [Ni (tyr) 2 (9EtGua) 2 ] × 5H 2 O; 3: [Ni (tyr)(guo) × 5H 2 O];4: [Ni (tyr)(ino) × 5H 2 O];5: [Ni (trp) 2 (9EtGua)(H 2 O)] × 2H 2 O, where tyr is tyrosinate, trp tryptophanate, ino inosinate and guo guanosinate. Thermogrammes are in agreement with the number of water molecules and nickel content (calculated as NiO), together with the ternary nature of these complexes. The binary compounds Ni(tyr) 2 × 3H 2 O and Ni(trp)2 × 3.5H 2 O were also obtained and the corresponding thermogrammes were registered for comparison purposes. Compounds 1, 2 and5 are water soluble; besides, 1 is fairly soluble in methanol. Compounds 3 and 4 seem to be polymeric. Infrared spectra clearly show the presence of bands either from the amino acid or the base suggesting nickel octahedral coordination through the carboxylic and amino acids groups and a nitrogen from the purine base. These compounds were obtained in water at pH close to 7.0. With other bases such as cytosine and uracil, or their corresponding nucleosides, the same synthesis failed to yield ternary compounds [1,2].

X-ray structures of two phosphazo analogues of β-diketones: N,N′-diphenyl-N″-trichloracetyl- phosphorictriamide and N,N′-tetraethyl-N″-benzoyl-phosphorictriamide have been determined. The results obtained in this study and the data reported earlier allow to discuss the impact of various substitutents on the phosphoricamido C(O)N(H)P(O) moiety.

GaAsO 4 · 2H 2 O was synthesized hydrothermally from Ga 2 O 3 and a K + -AsO 4 3- solution at pH=2. A single crystal structure determination showed that GaAsO 4 · 2H 2 O is isotypic with variscite and therefore the first gallium arsenate with octahedrally coordinated Ga(III). Crystal data: space group Pbca, a = 1016,0(1), b = 886,2(1), c = 994. 1(1) pm, R g = 0,0266. GaAsO 4 · 2H 2 O dehydrates at 439 K with formation of an amorphous material and poor crystalline GaAsO 4 . The crystal data of all known compounds with variscite structure have been compiled.

The new compound SrCuTe 2 O 6 has been prepared by quenching single crystals grown from a flux of SrCO 3 , TeO 2 and CuCO 3· Cu(OH) 2 . X-ray investigations show cubic symmetry, space group O 7 -P4 1 32, lattice constant a = 12.473(1), Z = 12. The crystal structure is characterized by square planar CuO 4 polygons and a one-sided open triangular oxygen coordination of Te 4+ , both incorporated in a Sr/O network. The one sided oxygen coordination of tellurium is completed by the lone pair of Te 4+ . Calculations of the Coulomb parts of lattice energy led to the position of the lone pair centre.

2,4,6-Trichloroborazine 2,4,6-Trichloroborazine is an important starting material for the preparation of many borazine derivatives, particularly for the parent borazine (HB=NH) 3 . Both are precursors for the CVD of boron nitride. Improved conditions for the synthesis of (CIB=NH) 3 to give high yields are reported.

Yellow single crystals of the isotypic phases Ca 51 [WN 4 ] 12 N 8 O 3 and Sr 51 [WN 4 ] 12 N 8 O 3 (triclinic, P1̄ (#2 ); a= 1056.4(3) / 1113.1(5) pm, b = 1239.7(3) / 1304.4(5) pm, c= 1598.2(3) / 1679.4(9) pm, α = 102.78(1)/102.47(2)°, β= 95.15( 1)/95.43(3)°, γ = 109.89(1)/109.77(2)°; Z = 1) were grown in a Tl-flux (Ca:Tl, molar ratio 5:1, W-crucible; T max = 1273K; reaction with N 2 , 1 atm, 36 h) or from pellets (Sr 2 N + W, molar ratio 6:1; T max = 1023K; reaction with N 2 , 1 atm, 36 h). The crystal structures contain tetrahedral anions [WN 4 ] 6- in addition to isolated nitride and isolated oxide ions, which are octahedrally coordinated by Ca and Sr, respectively.

Allyl thioether complexes [CpRu(P-P)(SRR′)]PF 6 (P-P = Ph 2 PCH 2 PPh 2 (dppm), Ph 2 PC 2 H 4 PP 2 (dppe), R = Me, Et, Ph, R′ = 3-propenyl, 3-cyclohexenyl, 2-methyl-2-buten-4-yl) and [CpRu(chir)(SRR′)]PF 6 (chir = (S,S)-Ph 2 PCHMeCHMePPh 2 , R = Me, CH 2 Ph, R′ = 2-methyl-2-buten-4-yl) are obtained from the corresponding thiolate complexes by reaction with the appropriate allyl bromide. Careful oxidation with dimethyldioxirane (DMD) gave the allyl sulfoxide complexes [CpRu(P-P)(MeS(O)CH 2 CH=CH 2 )]PF 6 (P-P = dppm, dppe). Double oxidation to the corresponding sulfinylmethyl epoxide complexes can be readily achieved with an excess of DMD. Oxidation of the chir complexes proceeds with only moderate diastereoselectivity. The structure of the (R, R/S, S) diastereomer of [CpRu(dppm)(MeS(O)CH 2 CHCH 2 O)]PF 6 was determined: monoclinic space group P2 1 /c (No. 14), a = 11.21(2), b = 16.762(9), c = 18.45(4) Å, β = 94.4(1)°, Z = 4. For a representative example, the decomplexation of the sulfoxide-epoxide ligand by sodium iodide in acetone was demonstrated.

Dissociation constants of amonium ion (K a = [H + ][NH 3 ]/[NH 4+ ], where [ ] denotes the con­centration) in 20 mass % ethanol + water mixtures with different concentrations of sodium chloride were determined by means of a glass electrode. The dissociation constants in pK a units (on molarity and molality bases) increase linearly with increasing ionic strength. Activ­ity coefficients of ammonia in the ethanol + water mixtures were determined by a transpiration method. The observed dissociation constants on the molality scale were compared with those calculated from the Pitzer equations modified on the basis of the principles of corre­sponding states. The observed values agreed with the calculated ones almost within experi­mental uncertainties.

A novel class of nucleoside analogues containing adenine, hypoxanthine, thymine, uracil, thiouracil and cytosine as the heterocyclic moieties have been prepared starting from 2-phenylcyclopropylamine. These compounds showed weak antitumor activity. The resolution of the racemates on an analytical scale was performed by HPLC using chiral phases.

A convenient pathway to a variety of β-and α-C-nucleosides has been developed by utilizing 1,3-dipolar cycloaddition reactions of various exocyclic and endocyclic heterocyclic ylides with β (5a) and α (5b) anomers of ethyl 3-(2′,3′-O-isopropylidene-5′-O-trityl-D-ribofurano-syl) propiolate, respectively. Assignment of configuration at exposition of the C-nucleosides could be made by a comparative study of the properties of corresponding α and β anomers with a reasonable degree of certainity.

1,3-Dipolar cycloaddition of dipolarophiles (1) and (2) with endocyclic heterocyclic azomethine ylides (4), (14) and (24), prepared in situ, leads to the protected β-and α-C-nucleo-sides (7), (8), (17), (18), (27) and (28), respectively. These, on subsequent hydrolysis, provide the corresponding C-nucleosides. The structures of all the synthesized com pounds are con­ firmed through analytical and spectral data. The assignment of configuration at C -1′ position of the C-nucleosides could be done by a comparative study of the properties of the corre­sponding α and β anomers with a reasonable degree of certainity.

The reaction of 5-amino-3-aryl-1-phenylpyrazoles (1a-d) with formaldehyde and secondary amines in boiling ethanol gave the corresponding 4-alkylaminomethyl derivatives (2a-f) and bis-(4-pyrazolyl)methane (4a,b) as byproduct. Such reaction with primary aliphatic and aro­ matic amines at room temperature afforded 1,3,5-trisubstituted (5a-h) and 1,3.5,7-tetrasubstituted tetrahydropyrazolo[3,4-d]pyrimidines (8a-k) respectively in good yield. Similarily, the Mannich reaction of 5-mercapto-3-phenyl-1,2,4-triazole (9) with secondary amines, in boiling ethanol, and primary aromatic amines, at room temperature, gave 2 -substituted aminomethyl derivatives (10a-c) and (14a-g) respectively,while with primary aliphatic amines, p-toluidine and p-anisidine,at room temperature,and with other primary aromatic amines, in boiling ethanol, afforded the cyclized products 12,4-triazolo[3,4-b]thiadiazines (13a-e); (15f,g) and (15a-e), respectively.

The Thai neem A. siamensis (Valeton) is the main source for botanical insecticides in Thailand. Although azadirachtin A (aza A) is present in Thai neem, there are some other related compounds which may contribute to its bioefficiency. Analytical HPLC of Thai neem samples showed a peak closely eluted with azadirachtin. A large-scale cleanup involving two liquid/liquid extraction steps, silica filtration, and finally two successive preparative HPLC separations, resulted in the pure compound, which was identified as 1-tigloyl-3-acetylazadirachtol by 1D -and 2D - 1 H and 13 C NMR spectroscopy.

Full ab initio optimizations were performed on the molecular structures of 24 fluorinated and chlorinated dibenzodioxines (PFDD/PCDD ) and dibenzofurans (PFDF/PCDF). Reasonable agreement was found by comparing the geometries of four calculated structures with known X-ray data from the literature. For the fluorine substituent, calculated electron densities (Mulliken total charges and π-electron charges) clearly demonstrate the opposite influence of the inductive (I) and mesomeric (M) effect. The changes in π-densities at carbons in ortho-, meta- and para-position are constant for each fluorine substituent (independent of degree, pattern, and position of substitution). It is thus possible to calculate the π-densities of the substituted dioxines by increments starting from dibenzodioxine. π-Charges from quantum mechanical calculations and the increment system show good agreement even for OctaFDD (O 8 FDD ), where eight substituent effects are acting additively. Compared with fluorine, the chlorine substituent exercises a smaller -I-effect and a clearly weaker +M-effect. The HOMO coefficients of the unsubstituted dibenzodioxine and dibenzofuran, extracted from ab initio calculations, yield a good explanation for the observed regioselective metabolic attack at the 2,3,7,8-positions. The squares of the HOMO-coefficients of the 2,3,7,8-positions in dibenzodioxine (DD ) are about ten times greater than those of the 1,4,6,9-positions. These HOMO coefficients are practically unaffected by halide substitution. But halogen substitution reduces strongly the electron density at the halogen-bound carbon, which, however, is a necessary prerequisite for the electrophilic oxygen transfer during metabolism. One would therefore expect halogen substitution of dibenzodioxine and dibenzofuran (DF) at the 2,3,7,8-position to hinder metabolism, as is indeed found. This provides a plausible explanation for the highly selective tissue retention of 2,3,7,8-substituted PCDDs and PCDFs. Our ab initio calculations of five tetra CDDs (T 4 CDDs) confirm the postulate of Kobayashi et al. [1 ] who, using semiempirical calculations, found a correlation between the toxicity of a dioxine congener and its absolute molecular hardness. The 2,3,7,8-T 4 CDD also exhibits the smallest absolute hardness (derived from the HOMO-LUMO energy gap) in our calculations.

The isotypic borophosphates Rb[B 2 P 2 O 8 (OH)] and Cs[B 2 P 2 O 8 (OH)] were grown under hydrothermal conditions. The crystal structures were solved by single crystal methods (Rb[B 2 P 2 O 8 (OH)]/ Cs[B 2 P 2 O 8 (OH)]: monoclinic, P2 1 /c, a = 676.2(3)/682.7(3), b = 1217.3(5)/ 1236.8(5), c = 885.0(4)/900.6(5) pm, β = 97.3(1)/ 98.1(1)°. Z = 4). The structures contain a complex framework of three-, four-, six-, nine- and twelvemembered rings of tetrahedra. Along [100] the twelve-membered rings are stacked to give wide channels which contain the Rb + /Cs + -ions in an icosahedral coordination.

The chiral ligands 1 - 5 were tested in the Cu 1 - catalyzed enantioselective cyclopropanation of styrene with ethyl diazoacetate. The new ligand 5 was synthesized by reaction of 1,4,8,11-tetraazacyclotetradecane (cyclam ) with (S)-propylene oxide and characterized by X-ray analysis.