Volume 44, Issue 8

The cation distribution and an energy level diagram of the spinel system ZnFeVO 4 —Fe 2 VO 4 have been calculated from the lattice constants. The results are in agreement with the Mössbauer spectra. Mössbauer data, Seebeck coefficients and activation energies lead to a model of both tetrahedral and octahedral conduction based on charge hopping. For Zn 0.4 Fe 1.6 VO 4 there exists only one iron species. Fe 2 VO 4 has at room temperature the cation distribution Fe 0.4 2+ Fe 0.6 3+ (Fe 0.6 2+ Fe 0.4 3+ V 3+ )O 4

FeV 2 O 4 has been prepared under oxygen with pressures between 10 -16.4 and 10 -9.9 bar. X-ray and Mössbauer investigations show that FeV 2 O 4 is not stoichiometric but contains Fe(III), and that an additional phase of corund type has been formed. At 1000 °C and p O2 , = 10 -16.2 bar the spinel with the lowest Fe(III) content, Fe 2+ (Fe 0.03 3+ V 1.97 3+ )O 4 , has been prepared.

The new chiral diphosphine 2 was synthesized from mucochloric acid. The structure of the NiI 2 -complex 7 was determined by single crystal X-ray analysis. 7 crystallizes in the orthorhombic space group P2 1 2 1 2 1 . The lattice constants (at 180 K) are: a = 914.1(2); b = 1422.0(3); c = 4112.5(10) pm.

The chiral diphosphine 1 reacts with [(diolefin)Rh(THF) 2 ]PF 6 (diolefine: 1.5-cyclooctadiene, norbornadiene) to form the complexes 4 and 5. The structure of 4 was determined by single crystal X-ray analysis. 4 crystallizes in the monoclinic space group P2 1 . The lattice constants (at 180 K) are: a = 974.0(6); b = 3889.2(29); c = 1309.4(5) pm; β = 105.25(4)°. The hydrogenation of methyl-α-acetamidocinnamate in the presence of 5 yields (R)-N-acetylphenylalanine methyl ester with 33% enantiomeric excess.

The title compound [Na(15-crown-5)][C 6 H 5 –C(NSiMe 3 ) 2 SnCl 3 F] is synthesized by the reaction of sodium fluoride with Ph—C(NSiMe 3 ) 2 SnCl 3 in acetonitrile solution in the presence of 15-crown-5 as white, moisture-sensitive crystals. The complex is characterized by its IR spectrum as well as by an X-ray structure determination. Space group P2 1 2 1 2 1 Z = 4, 4897 observed independent reflexions, R = 0.094. Lattice dimensions at 20°C: a = 1065.7(2), b = 1431.0(2), c = 2325.6(3) pm. The compound forms ion pairs with a bent Sn–F–Na bridge (bonding angle 119.0(5)°) and distances Sn–F of 196(1) and Na–F of 232(1) pm. The tin atom is in a distorted octahedral environment defined by the two N atoms of the symmetrically coordinated amidinato ligand, by three chlorine atoms, and by the fluorine ligand; the latter is in a trans-position relative to one of the nitrogen atoms.

The colourless compound RbLiS has been prepared as described earlier (H. Sabrowsky, A. Thimm, and P. Vogt-Mertens, Z. Naturforsch. 40b, 1759 (1985)) and its crystal structure determined by X-ray diffraction. Very hygroscopic RbLiS crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a = 4.424(3) Å, c = 7.255(2) Å. The structure was solved from 1635 counter reflections (155 symmetry independent reflections) by Patterson and Fourier methods (R = 0.031; wR = 0.031). The structure is characterized by layers of ∞ 2 [LiS 4/4 ]-tetrahedrons separated by double-layers of Rb + to form a PbFCl-type geometry.

The crystal structures of the isotypic monoclinic cyano complexes Cs 2 NaMn(CN) 6 (a = 759.7(1), b = 780.6(1), c = 1095.0(1) pm, β = 90.07(1)°) and Cs 2 KMn(CN) 6 (a = 769.8(2), b = 820.4(1), c = 1120.7(2) pm, β = 90.25(1)°) have been refined from single crystal X-ray data in space group P2 1 /n, Z = 2 (wR = 0.039 and 0.027, resp., using 1639 and 1732 independent reflections). The compounds are isostructural with cryolite, Na 3 AlF 6 , showing quite similar position parameters and nearly regular octahedra (average Mn—C= 198.8/199.6pm, C—N = 114.7/114.4pm for Na/K compound, resp.). The tilting of octahedra [Mn(CN) 6 ] 3— , [NaN 6 ] (Na—N = 248.5 pm) and [KN 6 ] (K—N = 280.0 pm) is compared to that of other cyano-cryolites and rationalized using radius ratio arguments in the form of a tolerance factor relation.

[WCl 4 (NCl)] 2 reacts in acetonitrile with the trimethylsilyl compounds Me 3 SiSR (R = Me, Ph), and Me 3 SiESiMe 3 (E = S, Se), with substitution of the chlorine atom of the N-chloronitreno group W=N–Cl and formation of CH 3 CN–WCl 4 (NSR) and CH 3 CN–WCl 4 (NEN)WCl 4 –NCCH 3 , respectively. Excess Me 3 SiBr reacts with CH 3 CN–WCl 4 (NSMe) to afford CH 3 CN–WBr 4 (NSMe). [CH 3 CN–WNCl 3 ] 4 was obtained from CH 3 CN–WCl 4 (NCl) and N(SiMe 3 ) 3 . The products were characterized by their IR spectra. Two X-ray crystal structure determinations were also carried out. CH 3 CN—WCl 4 (NSMe) forms twinned crystals, and only non-overlapping reflexions of one of the twin individuals were used for the structure determination (846 unique values, R = 0.055). Crystal data: a = 592.4(2), b = 758.8(2), c = 1203.7(8) pm, β = 95.06(4)°, monoclinic, space group P2 1 /m, Z = 2. The compound is a monomer in which the acetonitrile ligand is situated in the trans position to the W≡N–S̱̅–Me group. The bond lengths (W≡N 174(2), N–S 161(2) pm) and bond angles (WNS 176(1), NSC 102.1(9)°) are in agreement with the proposed formula. Crystal data for [CH 3 CN–WNCl 3 ] 4 : a = 1009.5(2), b = 1274.5(2), c = 1287.9(2) pm, β = 108.17(1)°, monoclinic, space group P2 1 /c, Z = 2 (2113 unique reflexions, R = 0.057). The compound forms tetrameric units, in which the W atoms form a square and are linked with one another via N atoms at alternating distances (W=N 171(2), W–N 207(2), W–NCMe 238(2) pm).

Bis(2,6-dimethoxyphenyl)nitramine (1) was found to be one of the products of the reaction of nitryl chloride, NO 2 Cl with 2,6-dimethoxyphenyl lithium. 1 was characterized through its NO 2 vibrations in the IR spectrum, v as = 1540 cm -1 and v s = 1290 cm -1 , and its identity was confirmed by its elemental analysis, 1 H and 13 C NMR data, and its mass spectrum. According to a single crystal X-ray structure determination, 1 is nearly planar about the central Ν—Ν bond; the Ν—Ν bond length is 136.3 pm. In addition, two further products of the reaction were also characterized, 1-chloro-2,6-dimethoxybenzene (2) and 2,4-dichloro-1,5-dimethoxybenzene (3).

The X-ray structure analysis of (trans-4,5-dimethyloxazolidin-2-ylidene)triphenylboron reveals a stereochemistry of the carbene ligand which is almost identical with that in transition metal complexes. Deprotonation of triphenylboron stabilized oxazolidin-2-ylidenes with NaH leads to (oxazolin-2-ato)borates, which have been N-alkylated with [R 3 O + ][BF 4 ~] or RI under mild conditions.

Valence force constants for N-benzylideneaniline and for two p,p′-disubstituted derivatives were estimated by means of a point-charge model using CNDO data. A vibrational assignment of bands which are sensitive to the electron donor-acceptor characteristic of substituents is proposed. The conformational changes are interpreted in terms of an intramolecular energy transfer between substituents.

The quaternary systems Ba(OH) 2 —BaCl 2 —H 2 O and Ba(OH) 2 —BaBr 2 —H 2 O were studied with the help of X-ray and neutron diffraction as well as IR, Raman, DTA, and TG methods. The following compounds have been established or confirmed: Ba(OH)Cl · nH 2 O (n = 0, 1/2, 2) and Ba(OH)Br · H 2 O (n = 0, 1/2, 2). The crystal structures (of hitherto unknown structure type) of Ba(OH)Cl- 2 H 2 O and Ba(OD)Cl · 2 D 2 O were determined by single crystal X-ray methods and neutron powder diffraction (space group P4/nmm, Z = 2, 621 unique reflections, R = 8.8 and 1.9%, respectively). Whereas the hydroxide ion in this layer structured compound is non-hydrogen bonded, i. e. no Η-bond donor group, nor it is bound to the Ba 2+ ions, the water molecules are involved in strong Η-bonds to adjacent OH - ions. The coordination of the barium ions is monocapped tetragonal antiprismatic (4 H 2 O and 5 halide ions). The IR and Raman spectra of Ba(OH)X · 2 H 2 O (X = Cl, Br) are assigned and discussed in terms of hydrogen bonding, isotopic shifts, and intermolecular coupling of the bands observed. The stretching modes of the OH - ions (3672 and 3667 cm -1 , 95 K) are shifted to higher wavenumbers by about 100 cm -1 as compared with those of free OH - ions.

Bis-(cobalticenium)triiodocuprate(I), [Co(cp) 2 ] 2 [CuI 3 ]≡(1) and cobalticenium-triiododicuprate(I), [Co(cp) 2 ][Cu 2 I 3 ]=1/9{[Co(cp) 2 ]9[Cu 6 I 11 ] ∞ 2 [(Cu 6 I 8 )2]}=(2) were obtained by reacting [Co(cp) 2 ]I with CuI in acetone 1 and acetonitrile 2, respectively. The crystal structure of 1 exists of cobalticenium cations and mononuclear planar anions CuI 3 2- . The crystal structure of 2 contains cobalticenium cations and two different types of iodocuprate(I) anions: an isolated hexa-nuclear ion Cu 6 I 11 5- built up by 6 edge sharing CuI 4 tetrahedra and polymeric layers ∞ 2 [Cu 6 I 8 ] 2- . In the latter anion Cu 6 I 11 components are two-dimensionally connected via 3 common edges and Cu(I) ions are distributed over two kinds of tetrahedral sites.

Phosphorothionic triamide SP(NH 2 ) 3 is obtained by slow addition of SPCl 3 dissolved in dry CH 2 Cl 2 to a satured solution of NH 3 in CH 2 Cl 2 at —50°C. Ammonium chloride is removed from the resulting precipitate by treatment with HNEt 2 followed by extraction with CH 2 Cl 2 . Coarse crystalline SP(NH 2 ) 3 is obtained after recrystallization from dry methanol. The crystal structure of SP(NH 2 ) 3 has been determined by single crystal X-ray methods (Pbca; a = 922.3(1), b = 953.8(1), c = 1058.4(2) pm, Z = 8). In the crystals the molecules show non-crystallographic point symmetry C 8 . The P—S bond (195.4(1) pm) is slightly longer than in SPCl 3 . From P—N bond lengths of about 166 pm a significant electrostatic strengthening of the P—N single bonds is assumed. Weak intermolecular hydrogen bonding interactions (N —H · · · N ≥ 329.5 pm; N — H · · · S ≥ 348.3 pm) are observed. Investigation of thermal properties shows a melting temperature of 115°C for SP(NH 2 ) 3 . According to combined DTA/TG and MS investigations above this temperature the compound decomposes by evolution of H 2 S and NH 3 to yield amorphous phosphorus(V)nitride.

The title compound 1 was obtained by the reaction of CuBr 2 and thiobenzamide in methanol. Its magnetic susceptibility and its EPR spectrum show it to be a Cu(II) compound. The two different ligands PhCSNH 2 (2) and [PhCSNH] - (3) show up by distinct absorption bands in the IR spectrum. The crystal structure of 1 was determined by X-ray diffraction (1289 observed, unique reflexions, R = 0.048). Crystal data: monoclinic, space group P2 1 /n, Z = 2, a = 912.0(2), b = 1859.7(8), c = 1006.2(6) pm, β = 110.73(4)°. There are dimeric, centrosymmetric molecules in which the copper atoms are linked via the sulfur atoms of either 2 or 3, probably 3. The copper atoms show the coordination of a flattened tetrahedron.

A novel synthesis of pyrazolo[4,3-c]pyrazoles via 1,5-dipolar cyclization of products of coupling of 2,3-dimethyl-1-phenyl-5-oxo-3-pyrazolin-4-diazonium chloride with active methylene reagents is reported.

Mitochondrial F 1 ATPase is inactivated by urea. Protection against urea inactivation is obtained when betaine, a methylamine found in different tissues, is added to the assay medium. Protection is also obtained upon the addition of either glycerol or dimethyl sulfoxide to the assay medium. The F, ATPase is rapidly inactivated at 4 °C. Inactivation by low temperature is prevented by betaine, glycerol and dimethyl sulfoxide. The protective effect of organic solvents and betaine against cold inactivation is prevented by urea.

The reactions of radiolytically generated OH radicals and H atoms with the cyclic dipeptides of glycine, alanine and sarcosine in deoxygenated aqueous solutions and the subsequent reactions of the transient peptide radicals were studied in the absence and presence of K 3 Fe(CN) 6 as oxidant by pulse radiolysis and product analysis. Hydroxyl radicals and H atoms react with glycine anhydride and alanine anhydride by abstracting an H atom bound at C-3; there is no evidence for any other site of attack at these two peptides. The resulting radicals have pK a values of 9.8 and 10.6, respectively. In the absence of an oxidant the radicals decay by second order (2k = 7.0×10 8 dm 3 mol -1 s -1 and 2k = 4.4×10 8 dm 3 mol -1 s -1 , resp.), the main fraction (94% of the glycine anhydride-derived radicals, 90% of the alanine anhydride-derived radicals) yielding dehydrodimers (G = 0.58 μmol J -1 and 0.56 µmol J -1 (in monomer units), resp.). A small portion however disproportionates via abstraction of a C-6-bound Η atom followed by isomerization to 2,5-dihydroxypyrazines (pK a values of the parent 2,5-dihydroxypyrazine at about 7.9 and 10.1) and subsequent addition of water to 2,5-diketo-3-hydroxypiperazines, thus indicating that the transfer of a carbon-bound hydrogen atom is prefered to the transfer of a nitrogen-bound hydrogen atom. No disproportionation products but three different dehydrodimers (G = 0.36, 0.18 and 0.04 µmol J -1 (in monomer units)) were found after irradiation of sarcosine anhydride. In this case a dose rate and solute concentration dependence of dehydrodimer formation indicates a radical-solute reaction converting part of the N-methyl radicals (21% of ‘initial’ attack) into the C-3-yl radicals. A rate constant of k = 600 ± 50 dm 3 mol -1 s -1 was obtained for this reaction by measuring and computing the dehydrodimer yields as a function of dose rate and solute concentration. Thus the observed transient spectrum accounts only for about 79% of the radicals from the ‘initial’ attack at C-3. The rate of oxidation of the glycine anhydride-derived radicals by Fe(CN) 6 3- reflects the pK a of the transient radical. The rate constant for oxidation of the (protonated) radical derived from glycine anhydride is: k = 1.0x 10 8 dm 3 mol -1 , the corresponding radical anion is oxidized with k = 3.1 × 108 dm 3 mol -1 s -1 . No change with pH was observed in the case of the alanine anhydridederived radicals (k = 7.9x 10 8 dm 3 mol -1 s -1 ). In contrast to the disproportionation, oxidation by Fe(CN) 6 3- leads to the removal of a proton from the heteroatom, a carbocation being the intermediate. The resulting dehydropiperazines rapidly add water to yield the corresponding 2,5-diketo-3-hydroxypiperazines (G = 0.61 μmol J -1 after oxidation of the glycine anhydride-derived radicals, G = 0.58 µmol J -1 after oxidation of the alanine anhydride-derived radicals). The radicals derived from sarcosine anhydride are readily oxidized with k = 4.0×10 8 dm 3 mol -1 s -1 , independent of pH. 1 H and 13 C{ 1 H} NMR-spectroscopic and mass-spectroscopic data of the products are given.

Calculations (AM 1, molecular mechanics) on pterocarpanoids and related compounds (homo-, heteroanalogues) are reported.

Several derivatives of 4-phenoxyphenoxy-ethyl and 4-phenoxyphenylethyl bearing carbonate and thiolcarbonate as functional groups were synthesized. The products were tested for their respective juvenile hormone activity for Triatoma infestans. None of them showed an activity comparable to that of Fenoxycarb which was used as the standard control. The synthetic procedures and the biological results are discussed.

Chiral halfsandwich complexes of sulfur monoxide and sulfur dioxide, [C 5 Me 5 RuCl(PR 3 )(SO x )] (R = isopropyl, cyclohexyl, x = 1, 2), were prepared from the coordinatively unsaturated precursors [C 5 Me 5 RuCl(PR 3 )]. The new compounds were characterized by 1 H 13 C, 31 P and IR spectroscopy.

The crystal structures of CuTe 2 Br and CuTe 2 I have been refined on the basis of single crystal data. Both compounds crystallize monoclinically in space group P2 1 /c. The structures are isotypic with that of CuTe 2 Cl. The lattice parameters of CuTe 2 Br are a = 834.5(8) pm, b = 492.8(4) pm, c = 1573.3(5) pm and β = 135.3(2)°. The unit cell dimensions of CuTe 2 I are a = 866.5(8) pm, b = 491.4(4) pm, c = 1649.6(3) pm and β = 135.1(2)°.

The complex [C 5 Me 5 Ru(PMe 3 ) 2 (SO 2 )] + is susceptible to nucleophilic attack at sulfur as shown by the reaction with ROH/Na 2 CO 3 (R = Me, Et, i-Pr) which gives the metallosulfonic esters [C 5 Me 5 Ru(PMe 3 ) 2 (SO 2 OR)].

Na 3 O(NO 2 ) and Na 3 OBr are isostructural and form solid solutions with a miscibility gap χ = 0.28 to 0.62 as referred to Na 3 OBr x (NO 2 ) 1-x , at room temperature. Above 593 Κ formation of mixed crystals was observed for all compositions. In contrast to pure Na 3 O(NO 2 ), the solid solutions do not undergo any phase transition in the investigated temperature range from 293 Κ to 130 K. These findings reveal that collective interactions between the dynamically disordered NO 2 - -groups are involved in the phase transitions of Na 3 NO 3 .