Volume 26, Issue 6

Diphenylboryl stannanes [ (C 6 H 5 ) 2 B] 4 - n Sn(CH 3 ) n (n = 0, 1, 2, 3) are produced from methyl chloro stannanes and (diphos) 2 Co[B(C 6 H 5 ) 2 ] 2 . However, no dibromoboryl stannanes (Br 2 B) 4 - n Sn(CH 3 ) n could be isolated in a similar reaction using (diphos) 2 Co(BBr 2 ) 2 but they are stabilized by addition of diphos yielding the complexes (Br 2 B) 4 - n Sn(CH 3 ) n · m diphos which contain B — P bonds.

The thermal decomposition of americium (III) -oxalate-decahydrate, americium (III)-formiate-0,2-hydrate, and americium (III) -carbonate-2-hydrate was studied by using mass spectromertic identification of gaseous decomposition products and X-ray identification of solid residues. The oxalate decomposition proceeded via four different hydration steps to the anhydrous oxalate, Am 2 (C 2 O 4 ) 3 , which decomposed to the anhydrous carbonate Am 2 (CO 3 ) 3 . This, in turn, was decomposed to Am 2 O 3 wia two intermediate carbonates Am 2 O (CO 3 ) 2 and Am 2 O 2 CO 3 . — The decomposition of Am (HCOO) 3 · 0,2 H 2 O proceeded to Am 2 O 2 CO 3 , which yielded Am 2 O 3 on further heating. As an intermediate a formiate AmO(HCOO) seemed to be formed. The decomposition of Am 2 (CO 3 ) 3 · 2 H 2 O proceeded to the anhydrous compound, which then follows the same decomposition pattern as the anhydrous carbonate formed by decomposition of the anhydrous oxalate.

Bis (trimethylsilyl) -diazene (BSD) is reduced by lithium at low temperatures to LiBSD 3 (solvent: diethyl ether), LiBSD (solvent: tetrahydrofurane) or Li 2 BSD (solvent: diethyl ester/few tetrahydrofurane). Unlike the stable Li 2 BSD the compounds LiBSD 3 and LiBSD decompose thermally at —15 respectively —78°. At this, LiBSD reacts to nitrogene and lithium-bis (trimethylsilyl) -amide, the latter of which forms an adduct with LiBSD, relatively stable at —45°.

The reversible one-electron insertion into mono- and 1,4-di-substituted benzene derivatives is favored by dialkoxyboron and especially by dialkylboron groups. The assumption that it should be the symmetric e 2u benzene molecular orbital which is occupied in the resulting radical anions can be supported by comparison of ESR coupling constants.

Single crystals of Li-acetylacetonate (Li-acac) were characterised by microscopical, IR-reflection and X-ray diffraction measurements. The space group was found to be C cca (orthorhombic). From the IR-spectra (polarised radiation) and the properties of the space group the probable arrangements of the molecular species in the crystal are deduced.

Cobalt (II) and Nickel (II) complexes of guajacole, vanilline and isovanilline were prepared. The coordinated ligand atoms were determined by IR- and NMR-spectroscopy. Spin densities indicating reactive ligand sites to which radicals can be attached were determined by NMR-spectroscopy.

The isotypic phases CaLiSi 2 and CaLiGe 2 have been prepared and investigated crystallographically. The silicon- resp. germanium atoms forms of infinite plane zig-zag-chains. The relations to the hitherto investigated ternary calcium lithium silicides and germanides as well as to CaSi and CaGe are discussed.

The hexafluoroplatinate of the organic amine was prepared via the Lanthanium salt and decomposed at 159°/10 -4 torr, yielding PtF 4 , propene and tri-propylammoniumhydrogenfluoride. Fluorinated organic products were formed in traces only.

The ternary oxides BaPrO 3 and BaTbO 3 crystallize in a slightly rhombic distorted perovskite lattice. According to the results of the optical and magnetic investigations both compounds contain also Pr 3 ⊕ ) and Tb 3 ⊕ , respectively.

The hydrolysis of 32 P-sodium polyphosphates (linear and cross-linked) in aqueous solution has been studied. The radiometric determinations indicate that the ortho-phosphate formation is a slow reaction, and that the amount formed by the linear variety is higher than that produced by the cross-linked form. There is a significant formation of metaphosphates during the hydrolysis of the cross-linked polyphosphate which is missing or at least reduced to a much lesser extent in the case of the linear polyphosphate.

IR spectroscopic investigations were conducted with poly-L-histidine (PLH) films, hydrous imidazole and pyrazole solutions and anhydrous N-methylimidazole with respect to protonation. Continuous absorption arises with increasing protonation and is maximally intensive with PLH, imidazole and N-methylimidazole when 50% protonated. The absorption indicates the formation of ΝΗ ⊕ ･·･·･·Ν bonds. The protons in these bonds are found in continuous energy level distribution. This continuity is due to the extremely large polarizability of symmetrical hydrogen bonds with double minimum potential well in which the proton tunnels. Thus on the one hand proton dispersion forces can arise, and on the other hand the anion fields can exert considerable influence. Both cause an energy level shift. The influence of these tunneling protons on the NH groups in PLH, imidazole and pyrazole is under discussion. The Cl ⊖ ions are added to these NH groups via NH · · · Cl ⊖ bonds. The CH groups in the N-methylimidazole are so acidic that CH · · · Cl ⊖ bonds are formed. In the case of PLH, imidazole and N-methylimidazole, the loss of the continuous absorption at more than 50% protonation is explained by the fact that each imidazole ring then possesses a Cl ⊖ ion and thus the NH ⊕ · · · N bonds are ruptured. With pyrazole, the continuous absorption continues to increase at 50% protonation. This is due to the fact that its pKa value is considerably less than that of the other substances. Hence H 5 O 2 ⊕ groupings are already formed preferentially before the NH ⊕ · · · Cl ⊖ groups. The rise of the continuous absorption in the case of the imidazole solution at a 100% or higher degree of protonation can be explained likewise. The corresponding rise with N-methylimidazole is accounted for by the formation of Cl ⊖ H ⊕ · · ·Cl ⊖ bonds.

The 35 Cl-NQR spectra of 27 chloroanilinium salts, [Cl x C 6 H 5-x NH 3 ⊕ ] X ⊖ , mainly chlorides and bromides, were investigated at 77 °K. The 35 Cl-NQR frequencies were tentatively assigned to certain chlorine atoms at the benzene ring. The substituent influence of the — NH 3 ⊕ X ⊖ group is discussed in terms of the NQR substituent parameter x. The electron attracting power of this group is clearly revealed. It decreases in the order ortho > meta > para of the substitution at the benzene ring with regard to the chlorine position. The substituent parameters x and σ(Hammett) are compared for the —NH 3 ⊕ X ⊖ group and the — NH 2 group. The anion in the anilinium salts, X e , seems to have no influence on the charge distribution within the aromatic system.

A furocoumarin intercalated between two base pairs of native DNA can photoreact with two pyrimidine bases engaging both its 4',5'- and its 3,4-double bond. This fact was evidenced studying the behaviour of the fluorescence acquired by DNA during irradiation at 365 nm. When this double reaction occurs, a cross-linking is formed between the two strands of DNA, as denaturation and renaturation experiments have demonstrated. The various furocoumarin derivatives have a very diverse ability to form cross-linkages, which is independent of their photobinding capacity. This different ability is due mainly to the structure of furocoumarins and to the steric relationships that the intercalated furocoumarin molecules have with the stacked pyrimidine bases.

The complete proton resonance spectrum of 1.2-diphenyl-cyclobutadiene-irontricarbonyl was measured including all observable 13 C-H-coupling constants within the four-membered ring. The couplings were assigned. Their analysis excludes the structure of a rectangular cyclobutadiene with alternating double and single bonds; the carbon-carbon bonds of the four-membered ring have nearly uniform bond orders.

More than 30 new unsymmetric disubstituted, enantiotropic nematic azobenzenes are described. In contrast to the high melting symmetric disubstituted liquid crystalline azobenzenes they partly have melting points only a little bit higher than room-temperature and nematic ranges of up to 34 °C. They represent an interesting new class of nematic liquid crystals.

Earlier work with buckwheat seedlings showed that dihydrokaempferol (3,5,7,4′-tetrahydroxyflavanone) (1) is a good precursor for cyanidin and quercetin. Since cell suspension cultures have several advantages for the quantitative comparison of the incorporation of a radioactive precursor into a product, the role of 1 in the biosynthesis of cyanidin was reinvestigated with cell cultures of Haplopappus gracilis. These cultures show good production of cyanidin-glycosides in blue light in a medium containing sucrose, 2,4-D and Fe-EDTA. Maximum anthocyanin production and maximal activity of phenylalanine ammonia-lyase is reached about 60 — 70 hrs. after the onset of illumination. The incorporation of 1 and of phenylalanine and 4,2′,4′,6′-tetrahydroxychalcone into cyanidin was compared under identical conditions after 1, 3 and 6 hrs. feeding time. 1 prooved to be by far the best precursor for cyanidin. The feeding time required was much shorter and the incorporation rates were much higher than in experiments with seedlings.

Short time treatment of intact Porphyridium cruentum cells with benzoquinone results in changes of the cell membranes, which lead to a higher permeability. This increased permeability allows the measurements of photosynthetic electron transport reactions with various electron donors, ac. ceptors and mediators, which cannot enter untreated cells. The capacity of benzoquinone to act as a Hill - reagent in vivo is interpreted as due to a double action of this compound: changing the permeability of the cells by reacting with the cell membrane coupled with the ability of the unreacted molecules to serve as electron acceptors.

The behaviour of the in vitro-activities of an alkaline and an acid deoxyribonuclease (DNase I and II, resp.), and of an inhibitor of DNase I of the kidney of mice, as well as of the DNA- and protein-content of kidneys and thymus, was studied in about 500 mice 4 hours to 21 days after exposure to folic acid in doses of 60 — 180 mg/kg body-weight. The most important results can be summarized af follows: 1. Activity of DNase I decreased and activities of DNase II and of a DNase I-inhibitor increased under the influence of high doses of folic acid. Significant effects were observed 16 — 24 hours after folic acid-injections. Extreme values (80% decrease [DNase I], 180% increase [DNase II, DNase I-inhibitor]) were reached after 2 and 4 days and were dose-dependent. Control values reappeared within 1 — 3 weeks. 2. Protein- and DNA-content of the thymus behaved very similarly to DNase I-activity of the kidney. 3. The increase of the DNase II-activity of the kidney under the influence of folic acid resulted from enzyme induction. As to the behaviour of DNase I loss of enzyme out of damaged cells and the induction of a DNase I-inhibitor in the kidney must be taken into account. 4. In many systems DNase I may control DNA-synthesis. Preliminary studies on the behaviour of folic acid-induced reaction of the kidney, when inhibited by X-irradiation, Actinomycin D, Actidione, or poly (vinylsulfate), suggest that DNase I-inhibitor plays a certain role in combining protein- and DNA-synthesis by inhibiting DNase I.

The growth of Yoshida ascites tumor cells in suspension culture is dependent on the presence of glucose but not dependent on energy production by aerobic glycolysis.

Investigations were made at the wild type and three eye colour mutants of the mosquito Culex pipiens L. The mutants are: “rot” (“r”, red eyes, sex linked, recessive), “weiss” (“w”, white eyes, sex linked, recessive), “ruby” (“ru” dark-red eyes, autosomal, recessive). By mendelian crossings, it could be shown, that “weiss” is epistatic over “ruby” and “rot”, “rot” is epistatic over “ruby”. “rot” and “weiss” are cell-autonomous mutants. In the wild type, two main substances could be identified. One seems to be an ommochrome, the other one a pterin (sepiapterin 1). The most important component is the ommochrome. In the eyes of “rot” animals the same two main substances could be identified, but there are obviously quantitative differences. More ommochrome and less pterin is formed. In the eyes of “weiss” animals no colour substances or their precursors could be detected. Only the eye pigments of the mutant “ruby” of Culex seem to be analogous to the mutant “brown” of Drosophila, both showing the same paperchromatographical pattern and the same spectrophotometric behaviour.

Putrescine and spermidine were the dominant polyamines in Tetrahymena cells. Spermine was present only in very small amounts. Changes in the amount of putrescine during and after the synchronizing heat treatment followed a definite quantitative pattern. Changes in the amount of spermidine were similar, though not so pronounced. The changes may be due to a varied influx of polyamines into the cells. Moreover, the exchange of polyamines between the cells and the culture medium must be specifically regulated since there seems to be a relatively greater accumulation of spermidine than of putrescine in the cells, and since spermine was almost excluded from the cells.

At pH 9,5 the DNA absorption maximum at 190 nm was shifted to 212 nm. This absorption maximum showed a bathochrome effect in the presence of IAA, GA and KI. The amplitude of this maximum was reduced at the same time. By addition of urea (0.1 —2.0 moles/l) the bathochrome effect, induced by the growth substances, was completely reversed, whereas application of NaCl (0.1 — 2.0 moles/l) did not affect the bathochrome movement of this DNA maximum. At pH 6.0 in the presence of 0.9% NaCl this DNA maximum did not show any visible bathochrome movement in the presence of the growth substances investigated. The DNA maximum at 260 nm did not show any alteration in the presence of growth substances. The thermal denaturation of DNA-complexes with IAA and GA showed, that with increasing concentration of these growth substances, the T m -value of the DNA was reduced. On the other hand, KI increased the T m -point of DNA. By biphasic melting at 260 nm and 280 nm no specific effect of the investigated growth substances on the stability of the A — T or G—C pairs was detected. Tryptophan and β-NAA closely related in structure to the auxins IAA and α-NAA did not reduce the T m -value of DNA. At pH < 7 IAA, GA and KI did not show any detectable influence on the T m -value of DNA. The data presented show that at a pH > 7 IAA, GA and KI are obviously bound to DNA by hydrogen bonds. There is evidence that these bonds are very unstable. Nevertheless, IAA and GA can loosen part of the hydrogen bonds of DNA double helix while KI cannot. Possible consequences of these growth substance effects on DNA are discussed.