Volume 28, Issue 9-10

Two new ternary phases were found by substituting copper with aluminium in the binary phase UCu 5 . Their compositions were determined as U 2 Cu 9 Al and UCu 3 , 5 Al 1,5 . X-ray powder diffraction investigations showed that the first one is hexagonal (S. G. P6 3 /mmc, No. 194, MgZn 2 type) with a = 4.998 = 0.005 A, c = 9.040 ∓ 0.005 Å and c/a = 1.809, Z = 1. UCu 3,5 Al 1,5 is also hexagonal but it belongs to the space group P6/mmm (No. 191, CaCu 5 type). The lattice parameters are a = 5.083 ∓ 0.005 Å, c = 4.155 ∓ 0.005 A and c/a = 0.817, Z = 1. In both structures atomic positions were determined by the trial and error method.

The preparation of the pure thio-anions GeS 4 4- and SnS 4 4- in aqueous solution is described. The vibrational spectra of the ions are reported and used for a normal coordinate analysis. The stretching force constant of GeS 4 4- is very similar to the value of the isoelectronic AsS 4 3- (M.V.F.F.: 2.12 vs 2.13 mdyn/Å). whereas the SnS 4 4 - stretching constant is significantly lower than the value of SbS 4 3 - (1.75 vs 2.09 mdyn/ Å).

A strong asymmetry in the electronic charge distribution on the central metal of Re 2 O 7 is caused by bridging oxygen atoms. This asymmetry is measured by determining the 185 Re, 187 Re-NQR transitions, NQR coupling constants and asymmetry parameter.

J(OSO 2 CF 3 ) 3 coukl bo obtained from CF 3 SO 3 H and J(OCOCF 3 ) 3 , N 2 O 5 and (CF 3 O 2 ) 2 O formed CF 3 SO 3 NO 2 which could be converted to CF 3 SO 3 NO by N 2 O 4 .

NH 2 Cl and NH 4 X react with transition metals of group IV to VI forming nitrides at relatively low temperatures. TiN-coated titanium is tested for its use in lead accumulators.

The reaction of H 2 NCl with higher chlorides of the transition metals of groups IV to VI in CCl 4 solution yields ammonium chlorocomplexes and ammonium chloride. The compounds are characterized by their IR and Raman spectra; their thermal decomposition to nitrides was studied by DTA.

Tetraperoxotantalates with organic cations as well as an oligomeric peroxopolytantalate were prepared for the first time by perhydrolysis of tantalum(V)ethoxide, Ta(OC 2 H 5 ) 5 , in the presence of bases. Guanidinium, tert-butylammonium and cyclohexylammonium salts of tetraperoxotantalic acid crystallize from ethanol as relatively stable compounds. The cell constants of these compounds are determined. By perhydrolysis of the ester in petroleum ether the tert-butylammonium salt of a peroxododecantalic acid was obtained. The molecular mass of this water soluble compound was determined with the ultracentrifuge.

Using magnetic susceptibility measurements the reactivity of AIN with a small addition of iron group elements was studied. The beginning of the reaction between the AlN and metal at about 1500°C was established.

When the reaction between CrO 3 and tert-butanol is carried out about thrice the amount of CrO 3 will be used up as is required for the formation of di-tert-butylchromate. That means that polychromates were formed. By a judicious choice of starting material concentrations solutions of almost pure mono, di and trichromates can be produced even though these compounds can be readily interconverted into one another. The monochromate can be separated from by-products via column chromatography and is obtainable as pure solid. The di and trichromate could not be obtained in a pure state because of their ease of decomposition. In solution they are stable at room temperature in the dark for 15-30 min and they can be employed for synthesis. IR spectra indicate that the alkyl portion in these polychromates is bonded similarly as in the monochromate.

Besides ‘Li 2 Al’ which was recently shown to be the phase Li 9 Al 4 there exists the phase Li 3 Al 2 characterized by preparation and X-ray diffraction methods. It cristallizes with a rhomboedric unit cell, R3̄m, a = 4.508 Å, c = 14.26 Å and z = 3 formula units (hexagonal setting). The structure can be looked at as a variant of the body centred cubic packing with Αl-atom layers of puckered six membered rings. The structural relation of the phases LiAl, Li 3 Al 2 , Li 9 Al 4 , Li is discussed.

Upon irradiation of C 5 H 5 V(CO) 4 in the presence of the Schiff base, derived from pyridine-carbaldehyde (2) and S-(—)-α-methylbenzyl-amine, two cis CO groups are replaced by the chelating ligand with the formation of complex 3. The reaction of C 5 H 5 W(CO) 3 Cl with 8-hydroxy-quinoline in boiling THF yields the oxinato complex 4. The analogous compound 5 is obtained in the reaction of C 5 H 5 Mo(CO) 3 Cl with 7-carboxy-8-hydroxyquinoline. The new asymmetric complexes with square pyramidal structure are characterised by C, H, N analyses, molecular weight determinations, IR, 1 H NMR, UV and mass spectra.

The IR and UV absorption spectra of the ammonium salt of cupferrone and manganese, cobalt, nickel, copper and zinc divalent cupferrate complexes are investigated. The IR absorption bands identified in the region 400-4000 cm -1 are given and assigned, especially those three related to M-O vibrations. In the UV absorption spectrum of the cupferrone metal complexes a characteristic shift in the maxima and minima appears.

UV-Photolysis (254 nm) of 5-bromouracil in aqueous solution in the presence of oxygen was investigated at pH = 6. Isodialuric acid and 4,5-dihydroxy-imidazolidone-2 as a secondary photoproduct were identified. The bromine atom from the homolytic splitting of the C-Br-bond and molecular bromine have no effect on the product distribution under our experimental conditions. In the presence of 2-deoxy-D-ribose and oxygen the UV-photolysis of bromo-uracil leads to uracil, isodialuric acid and 4,5-dihydroxy imidazolidone-2. The yield of uracil increases with increasing deoxy-D-ribose concentration while the yield of isodialuric acid and 4,5-dihydroxy-imidazolidone decreases.

A series of esters of phosphorous-phosphoric anhydride containing cyclic ester groups at one or both phosphorus atoms were prepared. The typical biphilic character of these compounds has been found. Unexpectedly observed lack of reactivity of anhydrides containing cyclic ester groups at trivalent phosphorus atom with respect to diethylphosphoric and acetic acids is the starting point for discussion on the mechanism of acidolysis. Unusual inertness of P III cyclic esters of phosphorous-phosphoric anhydride towards protic acids is discussed in terms of Hudson’s concept of steric retardation on quaternisation.

A new automatic peptide synthesizer is described. Most of the different single parts of apparates like the programmer, timer, “Multiport-Ventil,” magnetic valves or vessels are all commercially available and may be fixed together with a relatively small amount of costs. The efficiency of the new apparatus is tested by the automatic synthesis of biologically active peptide sequences like H-Asp(OH)-Ala-Phe-Ile-Gly-Leu-Met-NH 2 , H-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH 2 and Pyr-Tyr-Arg-Trp-NH 2 .

After γ-radiolysis of N 2 O saturated deoxygenated aqueous solutions of cellobiose (10 -2 Μ) the following products have been determined: Glucose, gluconic acid, 5-keto-glucose, 4-deoxy-glucose, 5-deoxy-gluconic acid, 2-deoxy-gluconic acid, 3-deoxy-4-keto-glucose, 2-deoxy-5-keto-glucose, 4-deoxy-5-keto-glucose, arabinose, 2-deoxy-ribose, ribose, erythrose, threose, 2-deoxy-tetrose, dihydroxy acetone, 3-deoxy-pentulose, 2-butanone-1,4-diol, 5-hydroxymethyl-furfural, carbon monoxid, and C 12 -acids (probably cellobionic acid and 2-deoxy-cellobionic acid). Analytical techniques were column chromatography, t. l. c. and g. l. c. combined with m. s.

Benzyl β-ᴅ-glycosides of 2-acylamino-2-deoxy-ᴅ-glucopyranose are usually prepared by multistep processes employing the glycosyl halides. Mixtures of benzyl glycosides which contain predominantly the α-glycoside result from acid catalyzed reactions with benzyl alcohol in one phase. In a two phase system, however, the lower solubility of the β-ᴅ-anomer becomes the determining factor in the resultant tandem equilibrium, and the β-ᴅ-glycoside predominates in the final product.

Additionally to the neutral and dicationic configuration for pheophytin a the monocation and monoanion can also be determined and characterized by means of absorption and fluorescence polarisation spectroscopy, by its relative aqueous solubility, and by its behavior in the electric field. The typical absorption- and APF-spectra for these prototropic configurations exist at the following normalities: > 2N HCl(pK ≈0) for the dication, 1.0-1.7 N HCl(pK ≈ 1.6) for the monocation, 0.1ɴ HCl—0.0003ɴ NaOH for the neutral configuration, and 0.3ɴ NaOH(pK ≈8,5) for the monoanion. Due to the quickly starting secondary reactions at elevated alkaline pH, the diaions cannot be proved definitely. At the transition monoanion →neutral configuration → monocation → dication, the position of the red band remains nearly constant (changes being < 150 cm -1 ); in contrast, the bands 2 and 3 as well as the B x and B y transition of the Soret band are considerably shifted bathochromatically (1200-2000 cm -1 ); from this fact it may be concluded that there is an inner ring oscillator with participation of the N-atoms. In the same sequence the intensity of band 3 decreases by approx. 40% and that of band 2 increases by the same value; in the ionic state the intensity of the red band and Soret band is at a maximum.

The electronic interaction between complex bonded cyclobutadiene and the phenyl ring is analyzed by 13 C- and 1 H-NMR-spectra. The cyclobutadiene-irontricarbonyl acts electron donating via the π-system and electron accepting via the σ-core.

The lowest excited states of maleic acid- and cyclopentendionderivatives have been investigated by UV-absorption and phosphorescence emission spectroscopy. While the first excited singlet-state S 1 is of 1 (nπ*)-type in all compounds, the lowest triplet-state T 1 was found to be a mixture of 3 (nπ*) and 3 (ππ*)-configurations. For the emitting derivatives (Ζ ≠ Η) phosphorescence-lifetimes and -quantum yields as well as the probability for intersystem crossing have been determined. Considering the inductive effects of all substituents on the S 1 (nπ*) -energy, Coulombpotentials for sulfur and iodine in terms of Huckel-parameters: h s = 0,2 and hj = —0,5 have been derived. The results of Hückel-MO-calculations can be correlated to the measured values of all compounds with the exception of the iodine containing derivatives.