Volume 29, Issue 3-4

The results of an X-ray structure determination on single crystals of CsFeF 4 are reported. The compound crystallizes tetragonally with α = 7.79 4 , c = 6.55 3 Å, z = 4, in spacegroup P4/nmm-D 4h 7 and is a hitherto unknown superstructure variant of the TlAlF 4 -type. Cesium exhibits 12-coordination (mean value Cs-F = 3.25 Å); the FeF 6 -octahedra are characteristically shortened normal to the FeF 4⁻ -layers (Fe-F = 1.96 2 /1.86 1 Å). An improved model is proposed and verified for a related structure of RbFeF 4 , showing the same features. Neutron diffraction studies on powder samples of CsFeF 4 show that both compounds are identical as for their magnetic structures.

KSiH 3 in HMPT and monoglyme solutions has been investigated by 1 H and 29 Si NMR spectroscopy; chemical shifts and coupling constants have been measured. The polysilyl anions H 3 SiSiH 2 ⊖ , (H 3 Si) 2 SiH ⊖ and (H 3 Si) 3 Si ⊖ have been prepared (a) from SiH 3 ⊖ with excessive SiH 4 , (b) from SiH 3 ⊖ and Si 3 H 8 and (c) from K and Si 2 H 6 or Si 3 H 8 in HMPT. They have been identified by 1 H NMR and IR spectroscopy, and their structures are deduceable from the spectral data.

The infrared and Raman spectra of LaAlTeO e , LaGaTeO 6 , In 2 TeO 6 and Y 2 TeO 6 are reported. Structure proposals are confirmed and the space group of Y 2 TeO 6 determined. A relation between spectral position of vibrational modes and quenching temperature of luminescence is outlined.

The syntheses of the oligomeric o-phenyleneoxides tribenzo [b, e, h] [ 1, 4, 7] trioxonin and tetrabenzo [b, e, h,k] [ 1, 4, 7, 10] tetroxadodecin are described.

The phase diagrams of the systems SnX 2 -SnY (X = Cl, Br, J, Y = S, Se, Te) were determined. New compounds were found in the systems SnBr 2 -SnS and SnJ 2 -SnSe.

The intermetallic phase Ca 0,95 Li 1,05 Sn has been prepared and its crystal structure determined. It crystallizes trigonal, a = 4.94 ± 0.01, c = 10.90 ± 0.02 Å, c/a = 2.21, space group P3ml-C 3v 1 in a new stacking variant of the CaIn 2 -type.

The transsilylation of hexamethyl- and heptamethyldisilazane as well as of Si-chlorinated methyldisilazanes by (CH 3 ) 2 SiCl 2 , CH 3 SiCl 3 and SiCl 4 has been investigated. The reactivity of the disilazanes decreases as the number of Cl-atoms in these molecules increases. A reactivity order (CH 3 ) 2 SiCl 2 <CH 3 SiCl 3 > SiCl 4 has been observed for the transsilylating agent. The shielding of all types of CH 3 groups present in the disilazanes investigated is additively dependent on the number of Cl atoms present in the molecules.

By substitution of a halogen atom in cyclic phosphazenes by isocyanate or isothiocyanate new members of this class of compounds are synthesized. These compounds are fairly stable against hydrolysis. Reaction of the new compounds with amines yields P 3 N 3 F 5 NHC(O)N(CH 3 ) 2 and P 3 N 3 F 5 NHC(S)N(CH 3 ) 2 . With elemental chlorine P 3 N 3 F 5 N = CCl 2 is formed. Numerous IR, NMR and mass spectra data of the new compounds are reported.

P 3 N 3 F 5 NHNH 2 reacts with P 3 N 3 F 5 Br to yield the symmetric hydrazide P 3 N 3 F 5 -NHNHP 3 N 3 F 5 . Compounds of the type P 3 N 3 F 5 NHNHC(O)CX 3 and P 3 N 3 F 5 NHN = CX 2 are readily prepared from P 3 N 3 F 5 NHNH 2 and carbonic acid chlorides and respectively aldehydes and ketones. The reaction product of P 3 N 3 F 5 NHNH 2 and CH 3 CH 2 CHO gives a dimeric derivate. Its structure was proofed by molecular weight, IR- and mass spectra.

Pressure treatment of TlInS 2 -I at 30 kbar, 300°C yielded the rhombohedral modification TlInS 2 -II (space group R3̄m, α = 3,83 Å, c= 22,23 Å, Z = 3). TlInS 2 -II has a-NaFeO 2 -structure and is metastable at all ρ, T-conditions investigated. At 30 kbar, 400°C, TlInS 2 -I and TlInS 2 -II transform to the hexagonal modification TlInS 2 -III, which was later found to be the normal pressure, low temperature modification of TlInS 2 . The crystal structure of Τ1Ιn 2 InS 2 -ΙΙΙ was solved from single-crystal data. The crystals are hexagonal, space group P6 3 /mmc, with a = 3,83 Å, c = 14,88 Å and Z = 2. The structure consists of sulfur layers with a sequence ABBA ... All octahedral sites are occupied by In, and one half of the trigonal-prismatic sites by Tl. The arrangement is such as to separate Tl and In by the greatest possible distance.

AgAlS 2 -I with chalcopyrite structure transforms at 25 kbar and 300°C to the new highpressure phase AgAlS 2 -II. The crystal structure of AgAlS 2 -II is trigonal, space group P3ml, with a= 3,50 Å, c = 6,84 Å and Z = 1. The structure is based on a hexagonally close packed arrangement of sulfur atoms with aluminium atoms in octahedral sites and silver atoms in tetrahedral sites. The AgS 4 -tetrahedra are considerably distorted, giving a coordination number 3 + 1 for the silver atoms.

In this investigation the isotope effect of uranium in the system Dowex 50 resin/ α- hydroxyisobutyrate solution was studied by mass spectrometry. A recycle ion exchange column was used for the separation experiments. The dependence of the isotope effect on the pH value and on the concentration of the α-hydroxyisobutyrate solution used as eluent was investigated. In the case of a 0.07 ᴍ and a 0.22 ᴍ α-hydroxyisobutyrate solution the elementary separation factor of uranium was calculated to be 1.00019 and 1.00006, respectively. In both cases an enrichment of 235 U in relation to 238 U was found in the solution. In addition the distribution factor of the uranyl ions in the investigated system was determined in the pH range between 2 and 6. The distribution factor depends strongly on the pH value. With increasing pH values the distribution factor decreases. The results obtained for the elementary separation factor and the distribution factor are compared with other investigations.

The 119m Sn Mössbauer spectra of trichlorostannido pentacarbonyl metalates(O), [M(CO) 5 -SnCl 3 ] - (M = Cr, Mo, W) 1-3, are reported and compared with the spectra of trichlorostannido complexes of manganese, iron, and platinum. With the isomer shift of β-tin. taken as dividing line between tin(II) and tin(IV) the compounds 1-3 can be regarded as tin(IV) derivatives with a noticeable π-backbonding ability of the SnCl 3 - ligand. There is an inverse relationship between the isomer shift and quadrupole splitting.

Mo(CO) 6 reacts with [N(C 2 H 5 )4][GeCl 3 ] (1) in refluxing tetrahydrofurane or benzene to form [N(C 2 H 5 ) 4 ][Mo(CO) 5 GeCl 3 ] (2). At room temperature the reactions of Ni(CO) 4 and 1 form [N(C 2 H 5 ) 4 ][Ni(CO) 3 GeCl 3 ] (3) in CH 2 Cl 2 and the disubstituted anion [Ni(CO) 2 -(GeCl 3 ) 2 ] 2- in tetrahydrofurane. The substitution of the aromatic ligand of mesitylene molybdenum tricarbonyl succeeds in boiling CH 2 Cl 2 and yields [N(C 2 H 5 ) 4 ] 3 [Mo(CO) 3 -(GeCl 3 ) 3 ] (4). Even two aromatic rings can be exchanged if dibenzenechromium is refluxed in acetone with 1. The yellow metalate(O) complex [N(C 3 H 5 ) 4 ] 6 [Cr(GeCl 3 ) 6 ] (5) is formed with 7% yield only.

The absorption of carbon dioxide and water vapour by zinc oxide to form basic zinc carbonate was studied for a range of gas pressures and reaction temperatures. Water pretreatment of the oxide was found to influence the initial stages of the reaction. The CO 2 - and water-contents of the products varied according to the reacting conditions but in all cases a highly-disordered basic zinc carbonate was formed which showed an increase in order on ageing.

The thiophosphonic and thiophosphinic halides, C 6 F 5 P(S)X 2 , (C 6 F 5 ) 2 P(S)X, and R(C 6 F 5 )P(S)X (X = F, Cl, Br, and R = CH 3 , C 2 H 5 , tert-C 4 H 9 , C 6 H 5 ) have been prepared, a) by addition of sulfur to the phosphorus(III) derivatives, b) by the reaction of chlorophosphoranes with H 2 S, and c) by halogen exchange reaction. The 31 P- and 11 F NMR data are discussed.

The relation between structure and reactivity of some aryl-cyanohydrins is discussed. The CNDO/2 method has been applied and the various energy terms of the fundamental state as well as the charge change of the carbonyl C-atom have been quantitatively analysed. The limitation of the present approach is pointed out.

SbCl 3⁻ ( 36 Cl) is prepared from SbCl 3 and NaCl₋( 36 Cl). In the homogeneous system SbCl 3⁻ ( 36 Cl)/1/CH 2 Cl 2 and in the heterogeneous system SbCl 3⁻ ( 36 Cl)/1, with solid SbCl 3⁻ ( 36 Cl), at 0-65 °C 1 is only labelled at C-1 and C-3; at 150 °C in the system SbCl 3⁻ ( 36 Cl)/1 C-2 is labelled too. Carbenium intermediates explain the chlorine exchange, in accordance with investigations with 14 C-labelled compounds too. The distribution of 36 Cl and 14 C in the molecule is proved by reactions to other labelled compounds.

Proton magnetic resonance spectra including all observable 13 C-H-couplings have been measured for chloro-cyclobutadiene-irontricarbonyl.bromo-cyclobutadiene-irontricarbonyl and methyl-cyclobutadiene-irontricarbonyl. The results are discussed with respect to structure and bonding. The structure of a cyclic diene with alternating double and single bonds can be excluded for the four-membered ring of all three compounds. Instead the complex bonded cyclobutadiene contains an electron distribution of higher symmetry with — despite the influence of the substituent — nearly uniform bond orders.

In both α-positions relative to the spiro-C-atom substituted spirobipyrans have the expected spiropyran structure, in spite of their exceptional behaviour that their pyrylium salts can not be isolated generally. Strong steric effects are responsible for the instability of those pyrylium salts, as it can be shown by UV- and IR-spectroscopic investigations.

Alkylation of N-alkoxy-N-aryl-carboxamides with tertiary oxonium salts and solvolysis by sodium hydroxide to aromatic azo compounds was systematically investigated. The reaction sequence is mechanistically explained and the role of nitrenoide intermediates is discussed.

In connection with the oxidation of nitrogen compounds the reaction of α-arylaminoacetophenone-oximes with ferric chloride was reinvestigated. This oxidizing process doesn't lead to four membered Δ 2 -1,2-diazetine-2-N-oxides, as formulated by BUSCH et al. but affords presumably substituted Δ 3 -imidazoline-3-oxides, because of the analytical and spectroscopic results.

The molecular structure of the product formed by the reaction of α-[p-Chloro-anilino]-acetophenone-oxime with ferric chloride was determined by single-cristal X-ray diffraction. The compound could be identified as 1-[p-Chloro-phenyl]-2-Z-[α-hydroximinobenzyl]-4-phenyl-⊿ 3 -imidazoline-3-oxide (2).

Single crystals of myoglobin enriched on Fe 57 with a diameter of about 0.5 mm were prepared. After deoxygenation crystallographic alignment and Mössbauer measurements were carried out at 77°K. In the experiment eight different orientations were selected by rotating the crystal around the b axis, thus, b axis and γ-ray propagation direction remained perpendicular to each other. From the intensity ratio of the quadrupole split spectra we derive the sign and the orientation of the principal axis of the electric field gradient. We find V zz to be positive and forming an angle of 40° to the b axis. From two alternatives consistent with our experiments we conclude that V ZZ is most likely oriented along one of the four Fe-N directions in the heme.

Light emission induced by x-irradiation of deaerated aqueous solutions of anthranilic acid (AH) is predominantly due to chemiluminescence. Within the range of pH 3.5 to pH 12 only emission of the anion (A-) is observed, in contrast to the fluorescence which exhibits a characteristic spectral change under the protolytic equilibrium A- + H + = AH (pK = 4.805). The chemiluminescence is proposed to involve reaction of ea q with the anthranilo radical Ø(NH 2 )+COO-, formed by OH attack upon A- or AH. Deprotonation of Ø(NH 2 ) + COO- occurs at pH > 7. Absolute yields of the x-ray induced emissions and absolute fluorescence quantum yields have been determined for the aminobenzoic acid isomers and for some related compounds.

N,N,N-Triethyl-N-[β-formyl-vinyl]-ammoniumperchlorat (1), a cationic α, β unsaturated aldehyde reacts with water at the carbonyl group. No addition was found to the olefinic double bound. This unusual behavior will be explained. The temperature dependence of the equilibrium constant measured by 1 H NMR spectroscopy result in ΔH = —3.8 ± 0.5 kcal/Mol, ΔS 30 °C = —20 ± 3 e. u.

The reaction of thiourea with C 3 O 2 yields a pyrimidothiazine derivative as a 1:2 adduct. An isomeric pyronopyrimidine is obtained by the action of C 3 O 2 on thiobarbituric acid. The structure of the reaction products of thioamides and C 3 O 2 has been reinvestigated.

In order to evaluate the contribution of the single tryptophyl residues to the fluorescence emission of elastase, the latter was analyzed as a function of pH, as well as in the presence of some perturbants and quenchers. Moreover, specific tryptophyl residues were converted to formyl-kynurenine by photosensitized oxidation. Our results suggest that the two external tryptophans 26 and 164 account for at least 50% of the total emission; out of the two partially buried tryptophans, the residue 83 is practically non-fluorescent, whereas the residue 12 contributes about one fourth of the elastase fluorescence. The residual fluorescence (about 25% of the total emission) is to be ascribed to the three deeply buried tryptophans 39, 132 and 232.