Volume 32, Issue 4

By calculating MAPLE, it can be discriminated between 2 alternatives of the H positions of an O-Η···Cl bridging system. Application of this result on a polytype crystal of this compound leads to further alternatives which are discussed. The existence of the polytype crystal cannot be explained by the H bridging system but only by the conditions during crystal growth.

With new X-ray data from a crystal of stoichiometric K 0.33 MoO 3 the crystal structure of this compound was refined until R(anisotropic) = 0.023. The characteristic distortion of the Mo-O octahedra is discussed.

In contrast to the Mössbauer spectrum of the orthorhombic compound Na 2 NiFeF 7 that of the manganous compound Na 2 MnFeF 7 gives evidence of two different iron positions. This rules out Na 2 MnFeF 7 to be isostructural with Na 2 NiFeF 7 , which crystallizes like most compounds Na 2 M II M III F 7 in the weberite structure, the M III ions occupying only one site in space group Imm 2-C 2v 20 . The Mössbauer data evaluated for the two iron sites (Fe 1/Fe 2 respectively) in Na 2 MnFeF 7 are: θ = 0/90°, φ = undetermined/70°, η = 0.6 both, Η = 551/541 kOe, V zz = ± 2.7 · 10 18 Vcm -2 both. NaMnFeF 7 is antiferromagnetic with a Neél temperature of TN = 94 Κ for both iron positions.

The room temperature modification of Ag 8 SiS 6 is orthorhombic, space group Pna2 1 , with α = 15.024, b = 7.428, c = 10.533 Å, Z = 4. A complete single crystal X-ray structure analysis shows the structure to contain tetrahedral SiS 4 (4-) units (Si-S 2.094(12) ... 2.130(12) Å) besides isolated sulfide groups coordinated by Ag; the compound may thus be formulated as Ag 8 (SiS 4 )(S) 2 . The coordination of the Ag atoms by sulfur is distorted tetrahedral (Ag-S 2.557...2.757 A), approximately trigonal planar (Ag-S 2.386...2.775 A, with one additional weakly bonded axial S at 2.991 ... 3.330 Å), or linear (Ag-S 2.414... 2.443 Å). Within the (ordered) Ag sublattice the temperature factors are significantly higher than for Si and S, indicating a certain mobility of the Ag atoms. The arrangement of the thiosilicate -sulfide part of the structure is pseudocubic face-centered, showing the close structural relationship to the disordered cubic high temperature modification of Ag 8 GeTe 6 .

Single crystals of Cu 2 OCl 2 were prepared and investigated by X-ray methods. Cu 2 OCl 2 crystallizes orthorhombic, space group D 2h 24 -Fddd (α = 969.9, b = 960.3, c = 746.2 pm). Cu 2+ has a distorted octahedral coordination. The JAHN-TELLER-Effect and effective coordination number are discussed.

BaMnSb 2 , SrMnBi 2 and BaMnBi 2 have been prepared and structurally characterized. The new compounds are isotypic and crystallize tetragonal in the SrZnBi 2 structure with the following constants: BaMnSb 2 : a = 4.53 ± 0.01 Å, c = 24.34 ± 0.03 Å, c/a = 5.37. SrMnBi 2 : a = 4.58 ± 0.01 Å, c = 23.13 ± 0.03 Å, c/a = 5.05. BaMnBi 2 : a = 4.63 ± 0.02 Å, c = 24.22 ± 0.05 Å, c/a = 5.23. The transition metal atoms form together with the semimetal atoms sheets of tetragonal pyramids separated by double layers of alkali earth atoms. In these double layers there are inserted Bi/Sb-square nets.

The title compound has been synthesized and its structure determined by threedimensional X-ray data.

The preparation and characterization of metal complexes of maleic acid hydrazide is reported, including Ca, Mn, Fe, Co, Ni, Cu, Zn and Pt-complexes, as well as the action of maleic acid hydrazide and one Pt-complex on Yoshida-ascites-sarcoma.

(Ph 3 P) 2 Pt(C 2 H 4 ) reacts with bis(fluoren-9-ylidenamino)-disulfide (2) to give a stable fluorenonthio-oximato complex (3). A ketimido complex (4) results from the reaction of 2 with Pt(PPh 3 ) 4 .

Heteropolymolybdates are obtainable from nonaqueous solutions. They are formed by reaction of molybdates or isopolymolybdates soluble in organic solvents with oxo acids or metal salts. Compounds with the anions TeMo 6 O 24 6- , M III Mo 6 O 24 H 6 3- (M III = Fe, Al, Cr), Μ II Mo 6 O 24 Η 6 4- (M II = Zn, Cu, Co, Ni), PMo 12 O 40 3- , as well as the novel heteropolyanion Ρ 2 Mo 4 O 19 4- were obtained. The IR and Raman spectra are discussed.

Tricarbonyl-η 6 -N-carbethoxyazepine-metal(0) complexes of chromium, molybdenum and tungsten are formed, when tricarbonyl-trisacetonitrile-chromium(0), tricarbonyldiglyme-molybdenum(0) and tricarbonyl-trisacetonitrile-tungsten(0), respectively, are treated with N-carbethoxyazepine. According to the 1 H and 13 C NMR spectra of the N-carbethoxyazepine metal complexes two different ligand motions can be activated thermally. The carbethoxy group rotates around the C-N-bond (Δ G 300 ≠ = 64.6 to 66.1 kJ • mole -1 ) and the azepine ligand itself moves against the tricarbonyl metal groups (Δ G 250 ≠ 45.6-52.1 kJ • mole -1 ).

The effect of pressure on the tetragonal/cubic phase transition in K 3 FeF 6 was studied to 35 kbar. A new phase which also occurs in K 3 TiF 6 , exists over a small temperature region at low pressures. A strong possibility exists that the K 3 FeF 6 tetragonal phase is isostructural with the corresponding phase found for the K 3 XF 6 (X = Ln, Y) compounds.

The polarographic behaviour of Ni(II), Co(II), Zn(II) and Mn(II) has been studied in 0.1 M KNO 3 . The temperature span studied varies from 15 to 55 °C. The reduction of Ni(II) and Co(II) has been found to be totally irreversible and that of Zn(II) and Mn(II) quasi-reversible over the temperature span studied. The kinetic parameters, k f,h 0 and an a for the totally irreversible reductions have been calculated by KOUTECKY’S treatment while for quasi-reversible reduction the kinetic parameters (a and k s,h ) have been evaluated by GELLINGS’ method. The activation energy of the totally irreversible reductions has also been determined. The effect of temperature has been discussed in terms of the variations in the values of the kinetic parameters.

The molecular structure of gaseous 4-fluoro-2′,4′,6′-trimethylbiphenyl was determined by electron diffraction. The average of two independend determinations leads to the following parameters for the structure: CC(ring) = 1.398(1),CC(methyl) = 1.522(5), CH(ring) = 1.082(6), CH(methyl) = CH(ring) + 0.015 = 1.097(6), CF = 1.324(7), Cl-Cl′ = 1.488(9) (inter ring bond), ∢(C,C,H) = 109.9(1.8)° (angle of methylgroup tetrahedra), α = 124.9(0.6)° (angle of ortho-methyl-groups towards the inter ring bond), φ = 77.5(2.1)° (angle of torsion between the planes of the two phenyl rings) which are in good agreement with respect to known structural data on biphenylderivatives. A very interesting result is the angle of torsion with 77.5° which is by 6.5° smaller than the value of 84(1)° determined by X-ray crystallography for the corresponding 4-iodo-compound in the crystalline state 1 . In all determinations known to us til now for comparable derivatives of biphenyl the angle of torsion was found larger in the gaseous state than in the crystalline state.

pH-metric studies on the interaction of Ni(II), Zn(II) or Cd(II) with 1,10-phenanthroline (Phen) or 2,2′-bipyridyl (Bipy) in the presence of phenylalanine (Phe) indicate the formation of 1:1:1 mixed ligand chelates and their monohydroxo derivatives. The addition of Phe takes place after the combination of Phen or Bipy with the metal ion is complete. The formation constants of the resulting complexes have been determined at 30 ± 1 °C and ionic strength (µ) = 0.1 KNO 3 and the ternary complexes involving Phen are found to be more stable than the corresponding complexes involving Bipy as primary ligand.

3-Amino-4-phenylhydrazono-2-pyrazolin-5-one (1) reacts with isothiocyanate to yield the corresponding pyrazolylthiourea derivatives (2 a-c). Whereas 2 a reacted with hydrazines to yield the pyrazolylamino-1,2,4-triazoles (3 a, b), it cyclised into the pyrazolo-[3,4-e]-as-triazine derivative (4) upon treatment with concentrated sulphuric acid. On the other hand, the pyrazolo[1,5-c]-S-triazine derivative (5) was formed from reaction of 2a with ethanolic sodium ethoxide. 3-Amino-2-pyrazolin-5-one (8) reacted with ethyl acrylate to yield a mixture of the 4-dialkylated derivative (9) and the pyrazolo[3,4-b]pyrone (11). Compound 11 could be converted into the corresponding pyrazolo[3,4-b]pyrones (12) and (13) by the action of acetic acid hydrochloric acid mixture and of concentrated sulphuric acid, respectively.

On illumination flavin reacts from its triplet state with dihydroaromatic systems at room temperature yielding 1,5-dihydroflavin. Substrates which are substituted with methyl groups to hinder aromatisation (3,3-dimethyl-1-phenyl-1,4-cyclohexadiene, ergosterol, N-methylacridan, 1,3,10-trimethyl-1,5-dihydro-5-deazaisoalloxazine) yield at -40 °C 4a-substituted 4a,5-dihydroflavins (adducts), which on warming split homolytically, yielding a 1:1:1-mixture of 1,5-dihydroflavin/starting flavin/dimerized substrate after disproportionation and dimerisation, resp. In the case of unblocked substrates these adducts are not UV-detectable even at -80 °C but split heterolytically, yielding 1,5-dihydroflavin and oxidized substrate in a 1:1-ratio.

The synthesis of Cu(II), Mn(II), Fe(III), Ti(IV), Zr(IV), Ce(IV), Th(IV) and UO 2 (II) complexes with 4-methyldaphnetin and 4-methylesculetin is described. Structural information on coordination of the ligand with metals has been obtained from infrared spectroscopy. Results of thermal analysis and magnetic measurements of some of these complexes are reported.

The reactivity of heterocyclic α,β-unsaturated ketones towards the title compounds has been studied. A pyrimidine, pyrazoline, isoxazoline and a fused pyrrolidine rings have been built up. Mannich reaction was tried with the pyrazoline derivative (4 d). Bromination of the 2-cinnamoyl compounds (1 a-c), and cyclization of the products were also undertaken.

A detailed investigation has been carried out on the effect of alloxan, alloxanic acid and ninhydrin on the rate of disappearance of alanine in buffered aqueous solution at pH 7 and on amino acids in blood both in vitro and in vivo. The results obtained indicate the possibility that the interaction of alloxan and tissue amino acids might have an important role in the diabetogenic effect of alloxan.

Reaction of diphenylcyclopropenone with bromoacetic acid, trifluoroacetic acid and benzoylformic acid leads to crystalline complexes.

Organic synthetic transformations are described in terms of a set of 43 distinct general reaction-matrix types, of which ten account for rearrangement reactions only. The schemes identified conform partially to the semi-empirical rules governing synthetic transformations, as previously defined by UGI et al. 30 .

A specialized set consisting of about 1,900 organic reactions has been analyzed to determine the distribution of reaction matrices R̃ according to a mathematical model of chemistry. The dynamical properties of the data-base have a very uneven (exponential) distribution. The results conform to the overall pattern of previous more restricted random sample analyses. A subset of ten R̃-matrices accounts for over 92% of the one-step interconversions between chemically stable or well-defined species which describe a reaction sequence. The implications of the findings for synthesis-planning are set out.

Na 2 [Fe(CN) 5 NO] reacts with two molar equivalents of sodium anilide in liquid ammonia forming a yellow crystalline diamagnetic complex Na 4 [Fe(CN) 5 N(O)NC 6 H 5 ]. The reaction is an analogon to the well-known nucleophilic attack of OH- ions in water which yields pentacyanonitroferrate (II).

Exchange of the cyclopentadienyl ligand from methylcyclopentadienyl-manganese-tricarbonyl by benzene, toluene, xylene, mesitylene and other aromatics with AlBr 3 as catalyst gives cationic aromatic manganesetricarbonyl complexes. The amount of AlBr 3 and the addition of aqueous HBr do not only influence the yield but also the purity of the products. With this new method C 6 H 6 Mn(CO) 3 + can be prepared in high yield from a relatively inexpensive starting material.

The reaction of trans-bromotetracarbonyl-(phenylcarbyne)chromium with chlorine and bromine as well as cerium(IV) and manganese(III) compounds results in the complete degradation of the complex. Benzotrihalides or benzoic acid derivatives and, in some cases, also dibenzyl are isolated as products of the carbyne ligand.

A refinement of the Ba 2 CuF 6 -structure by neutron diffraction leads to improved site parameters of the F - -ligands. The CuF 64- -polyhedra are distinctly ortho-rhombic, in complete correspondence with EPR-spectro-scopic results.

A single phase binary amalgam of the composition NiHg was found to form at room temperature after an extended period of time (approx. 2 years). X-ray powder diffraction analysis enabled us to determine the crystal structure. The compound crystallizes tetragonally with a = 4.22 Å and c = 3.14 Å. It belongs to L 1 0 crystal structure type.