Band 22, Heft 3

Tetraphenyl-imidodiphosphinsäure und ihr Diimid bilden die monomeren Kupfer (II) -Chelate [N (Ph 2 PO) 2 ] 2 Cu und [N (Ph 2 PNH) 2 ] 2 Cu. Die EPR-Spektren fester Proben zeigen die aufgelöste Kupfer-Hyperfeinstruktur, die sonst nur von magnetisch verdünnten Kupferkomplexen gefunden wird. Dank der Auflösung kann aus den Einkristallspektren von [N (Ph 2 PO) 2 ] 2 Cu der minimale Cu - Cu-Abstand im Gitter zu ~ 10 Å bestimmt und das Austauschintegral abgeschätzt werden. Die starke Isolierung der paramagnetischen Zentren findet ihre Erklärung in den räumlichen und Bindungsverhältnissen der Phenylphosphazen-Brücke zwischen den Ligandenfunktionen. In der Additionsverbindung [N (Ph 2 PO) 2 ] 2 CuPyridin 2 ist die Isolierung durchbrochen. Aus den EPR-Parametern ergibt sich für die Sauerstoffverbindung eine erheblich ionische, für das Iminoderivat eine weitgehend kovalente Bindung. Die Elementarzelle von [N (Ph 2 PO) 2 ] 2 Cu enthält zwei um etwa 25° zueinander geneigte Molekelarten.

Die Bildung von Dicyanamido- und Tricyanmethanido-cupraten (II) in Lösung wird spektralphotometrisch verfolgt, die Komplexkonstanten der in wäßriger Lösung nachgewiesenen Verbindungen Cu[N(CN) 2 ] ®, Cu[N(CN) 2 ] 2 und Cu[C(CN) 3 ]© werden bei der Ionenstärke I=1 und bei 25 °C zu 31,5, 5,8 und 10,2 bestimmt. Die Darstellung anionischer Komplexe Kat, [Cu(N(CN) 2 ) 4 ] [Kat= (CH 3 ) 4 N, (C 6 H 5 ) 4 As] wird beschrieben. Aus spektralphotometrischen Messungen an Lösungen dieser Verbindungen folgt eine verzerrt tetraedrische Struktur der komplexen Anionen, wie sie auch für das kristalline Tetraphenylarsonium-Salz anzunehmen ist. Dagegen besitzt das feste Tetramethylammonium-Salz ebenso wie Kupfer (II)-dicyanamid eine polymere, verzerrt oktaedrische Struktur.

Die IR-Spektren der Verbindungen C 6 F 5 PX 2 (X = H, CH 3 , Cl, Br), Tris (pentafluorphenyl) - phosphin und Tris (pentafluorphenyl) phosphinoxyd im Bereich 4000 > v (cm -1 ) > 300 werden mitgeteilt und nach Gruppenfrequenzen zugeordnet. Der Frequenzgang der PO-Valenzschwingung in der Reihe R n (C 6 F 5 ) 3-n PO (R = CH 3 , C 2 H 5 , C 6 H 5 ) wird eingehend diskutiert.

Die chemischen Verschiebungen δp der Pentafluorphenyl-substituierten Phosphine und Phosphinoxyde des Typs (C 6 F 5 ) n R 3-n P und (C 6 F 5 ) n R 3-n PO (für R= CH 3 , C 2 H 5 , C 6 H 5 ) werden mitgeteilt und diskutiert.

Durch 31 P-Kernresonanz-Untersuchungen im festen Zustand wird gezeigt, daß die Verbindungen PCl 5 ·JCl, PCl 5 ·JBr, PCl 5 ·NbCl 5 , PCl 5 ·TaCl 5 und PBr 5 ·JBr PCl 4 ⊕ - bzw. PBr 4 ®-Kationen enthalten und daher salzartig zu formulieren sind. Die chemischen Verschiebungen für PCl 4 ⊕ werden bei - 86 bis -80 ppm beobachtet. Für das PBr 4 ⊕ -Kation ergibt sich eine chemische Verschiebung von + 72 ppm. Im PCl 5 ·AlCl 3 liegen keine PCl 4 ⊕ -Kationen vor.

Kinetische Untersuchungen über den Mechanismus der Bildung von Verbindungen L′M (CO) 3 (M=Cr, Mo; L′=Aromat, Triolefin) aus LM(CO) 4 (L = Norbornadien) belegen, daß die Reaktionsgeschwindigkeit sowohl von der Konzentration als auch von der Art von L′ abhängt. Die Interpretation der Ergebnisse unter Zugrundelegung des Bodenstein- Theorems läßt erkennen, daß als einleitender Schritt der Umsetzung die partielle Lösung der Diolefin-Metall-Bindung in LM (CO) 4 anzunehmen ist. Im Fall L′=Triolefin ergibt sich ein additives Geschwindigkeitsgesetz mit einem Term zweiter Ordnung, d. h. hierbei erfolgt primär neben der Dissoziation auch ein direkter Angriff von L′ auf das Zentralatom des Ausgangskomplexes.

In CCl 4 gelöstes SbFCl 4 reagiert mit Dichlormonoxid unter Bildung von SbOFCl 2 , dessen Darstellung, Eigenschaften und IR-Spektrum beschrieben werden. Danach polymerisiert das Oxidhalogenid mit Hilfe der Sauerstoffatome, wobei die Koordinationszahl des Antimons 5 beträgt (Symmetrie C 2v )·

Synthesis and isolation of two unreported complexes of copper (II) and 2,5-diamino adipic and 2,6-diamino pimelic acids are described together with proposed structures and analytical data. Attempts to synthesize group VIII metal complexes using these two acids as ligands are mentioned; these were for the most part unsuccessful. The ratio of copper (II) to ligand is 1:1 with one molecule of water, and it is predicted that the structures involve two ligands acting as double bidentates and bridging two copper ions. The exceedingly low solubility of the compounds leads to the conclusion that they are non-ionic.

The chelating tendencies of the alpha amino acids with platinum group metal ions are well known; with the dibasic acids, complexes have been reported involving palladium (II) and platinum (II) with both aspartic and glutamic acids. There is no mention of the successful synthesis of complexes between these acids and rhodium (III), however. This communication reports a method of preparation for these two complexes as well as an alternative method for the synthesis of the palladium (II) complex with aspartic acid. It is shown that the mole ratio of rhodium (III) to aspartate or glutamate is one to three, that the ligands act as bidentates, and that the aspartic acid complex. Infrared and elemental analytical data are given.

Die G-Werte der Wasserstoffbildung aus Mischungen von Cyclohexan mit Thiophenol und Thiophenol-d 1 wurden bestimmt. Die Wasserstoffausbeuten werden durch den Zusatz von Thiophenol nicht wesentlich vermindert. Dieses Verhalten steht im Gegensatz zur Wirkung anderer aromatischer Verbindungen und hat seine Ursache in der Labilität der S—H-Bindung. Durch Deuterierung des Thiophenols an der S—H-Gruppe konnte bewiesen werden, daß ein großer Teil des gebildeten Wasserstoffs aus der S—H-Gruppierung stammt. Aus den Ergebnissen lassen sich quantitative Aussagen über den Anteil an ionischen Prozessen bei der Wasserstoffbildung aus Cyclohexan gewinnen.

The reactions of the OH radical with H 2 S and SH ⊖ are very fast (k = 1.1·10 10 and 5.4·10 9 mole -1 liter sec -1 , respectively). The hydrated electron reacts with H 2 S (1.1·10 10 ) but does not react with SH ⊖ . The rate constant of the reaction CNS+SH ⊖ CNS ⊖ +SH was found to be equal to 9.8·10 8 . Species absorbing at 3800 Å (e ∼ 10 4 mole -1 liter cm -1 ) are formed in these reactions of H 2 S and SH ⊖ The intensity of this absorption is very low in strongly acid solutions, increases with pH, goes through a broad maximum at about pH=7, reaches a lower plateau between pH = 8.5 -10.5 and decreases in strongly alkaline solutions. At pH values below 7, the intensity is dependent on the concentrations of both SH ⊖ and free H 2 S, i. e. at constant SH ⊖ concentration a stronger absorption occurs if more free H 2 S is present. In the plateau below pH = 8.5 -10.5, the intensity is practically independent of the SH ⊖ concentration above 4·10 -5 mole/l. The decay of the 3800 A absorption after the pulse is first order with τ 1/2 = 5 μsec independent of the OH ⊖ and SH ⊖ concentrations in alkaline solutions.Below pH = 7, the absorption disappears by second order, the rate constant being larger at lower pH values. SH or S ⊖ absorb weakly in the near UV and do not contribute to the 3800 Å absorption. This absorption is attributed to the ions H 2 S 2 ⊖ or H 2 S 2⊖ in alkali and to H 2 S 2⊖ or higher complexes such as H 3 S 4 ⊖ in acid. The first order decay of 5 μsec is attributed to the spontaneous decomposition of S 2 H 2⊖ into S ⊖ +SH ⊖ . Two S ⊖ ions form S 2 2⊖ (2 k=2·109 mole -1 liter sec -1 ). The complex H 2 S 2 ⊖ is formed in the fast reaction SH + SH ⊖ ↔ S 2 H 2 ⊖ (dissociation constant about 4·10 -5 mole/l). The formation of an intermediate complex SHOH ⊖ in the reaction of OH with SH ⊖ is discussed. This intermediate reacts with either SH ⊖ to form S 2 H 2⊖ or with OH ⊖ (or other proton acceptors such as ΗΡΟ 4 2Θ ) to form S Θ + H 2 O+OH Θ .

Die NMR-Spektren von monosubstituierten Alkylcycloheptarienen werden diskutiert. An Hand der chemischen Verschiebung des CHR-Protons in 7-substituierten Cycloheptatrienen und durch die Kopplungskonstanten mit den olefinischen Nachbarprotonen wird eine bevorzugte äquatoriale Stellung des Substituenten (das Proton in 7-Stellung steht dann axial) wahrscheinlich gemacht.

The trifluoroacetylation of thymidine at room temperature was performed using trifluoroacetic acid phenylester in pyridine. A selective protection of the 5′-position was not possible: Even low molar quantities of the trifluoroacetylating agent gave rise to bis-trifluoroacetylation. The bis-trifluoroacetyl derivatives of thymidine and 5-bromo-deoxyuridine were purified by vacuum sublimation. The completely trifluoroacetylated deoxyribosides of uracil, 5-iodouracil and adenine underwent decomposition during sublimation.

Es wird die Synthese des Primins, ausgehend vom o-Vanillin, beschrieben. In der gleichen Weise konnten durch Variation der Reaktionskomponenten in der Synthesefolge zwei Isomere des Primins mit verzweigten Alkylseitenketten dargestellt werden. Bei der übersichtlichen Synthese der stellungsisomeren 2-Methoxy-5-alkyl-p-benzochinone diente als Ausgangsmaterial Resorcin, das mit Carbonsäuren umgesetzt die 2.4-Dioxyvalerophenone gibt. Nach der Reduktion zu den 2.4-Dioxyalkylbenzolen erhält man durch Oxydation mit Kaliumnitrosodisulfonat und Methylierung mit Diazomethan die entsprechenden alkylierten Methoxychinone.

Taka-amylase A is highly protected from heat inactivation and denaturation by the presence of its substrate, starch. The effect of pH on the protective action was studied to find the relation between the protective action and the state of ionization of taka-amylase A. The separation of protective effect of substrate from that of hydrolysis products was made by digesting starch with taka-amylase A before incubation to find the difference of protective abilities of substrate and hydrolysis products. The stabilization of the higher order structure of enzyme protein, depending on the state of ionization of enzyme protein, brought about by the formation of enzyme-substrate and -product complexes seems to be responsible for the appearance of the protective effect observed.

Following treatment with the β-galactosidase inducer [methyl- 3 H] -thiogalactoside, an induceracceptor-complex was isolated from extracts of E. coli K 12 using DEAE cellulose chromatography. Enzymatic digestion with trypsin suggested that the inducer was bound to a protein component. Specific radioactive peaks demonstrated acceptor activity in the inducible strains E. coli K 12 and ML 3, but different results were obtained using the non-inducible mutants ML 35, ML 308 and ML 309. The potent inhibitor of TMG-induction, o-nitrophenylfucoside, reduced the radioactive acceptor peak and caused a similar inhibition of β-galactosidase synthesis, p-nitrophenylfucoside was ineffective. Further evidence is presented for the in vitro formation of an inducer-acceptor-complex in cell free extracts of E. coli K 12.

Organophosphor-Verbindungen, vorwiegend insektizider Natur, wurden hinsichtlich ihres Verhaltens gegenüber Xanthindehydrase untersucht. Hierbei erwiesen sich Ester, die wie Parathion einen sauren Acylrest besitzen, als wirksame Inhibitoren, und zwar um so ausgeprägter, je kürzer die an das zentrale Phosphoratom gebundenen Alkoxygruppen sind. In reinen Enzymlösungen trat der Effekt stärker hervor als in Milch. Phosphorsäure-Ester hemmten stärker als Thionophosphorsäure-Ester. Es gelang, die Inaktivierung durch Dialyse des inhibierten Enzyms aufzuheben. Vermutlich findet daher lediglich eine Adsorption am Enzym, aber keine Alkylierung statt.

The radiosensitivity of dry ribonuclease was determined at various temperatures ranging from 90 °K to 300 °K and using 60 Co gamma-radiation, 2 MeV protons, and 2 MeV deuterons. The cross section for the inactivation of RNase S (T) is, in this range, given as a function of temperature by S(T) =S 0 +S 1 ·e -Ea/RT. For inactivation of ribonuclease with Co gamma-rays we found S 0 =0 and E a =1000 cal/mole; S 1 = =0.125 Mrad -1 when irradiation is carried out in vacuo, and S 1 =0.265 Mrad -1 in oxygen. With protons and deuterons the following values were determined: S 0 =1.28·10 -14 cm 2 , S 1 =19.5·10 -14 cm 2 , E a =1050 cal/mole for 2 MeV protons; S 0 =2.45·10 -14 cm 2 , S 1 =31·10 -14 cm 2 , and E a = 1050 cal/mole for 2 MeV deuterons. Furthermore, by analysis of some recent data from the literature we found that the cross section for inactivation by ionizing radiation of various enzymes, bacteriophages, and bacterial spores in the range from 4 °K to temperatures higher than room temperature can satisfactorily be described by the more general equation S(T) =S 0 +S 1 ·e -E₁/RT +S 2 ·e -E₂/RT , with E 1 =1 kcal/mole and E 2 =4 kcal/mole being constant for all objects and for all circumambient conditions tested. This correlation between inactivation cross section S (T) and temperature T shows three mechanisms of inactivation to occur in biological objects: one (S 0 ) being independent of temperature, while the two others have apparent activation energies of 1 kcal/mole and 4 kcal/mole, respectively.

Die chemisch-enzymatische Charakterisierung des von Myxoviren oder bakteriellem Endotoxin in vivo und in vitro induzierten endogenen Pyrogens und des einfachen Kaninchengranulozyten-Pyrogens weist darauf hin, daß die Wirkung der endogenen Fieberstoffe an Protein gebunden ist. Filtrationsversuche mit Virus-induziertem Pyrogen aus Leukozyten sprechen für ein Mol.-Gew. um 30 000, während die Säulenchromatographie einen Bereich von 30 000 - 40 000 ergibt. Daneben treten in geringem Umfang auch größere Moleküleinheiten (Aggregate?) auf. Die mit verschiedenen Myxoviren in vitro induzierten Fieberstoffe zeigen keine Unterschiede hinsichtlich Proteinnatur und Mol.-Gew., so daß sie eng verwandt sein dürften.

The breakdown of endogenous proteins in the homogenates of rat liver and spleen, was investigated. The shape of the p ʜ -activity curves is shown to depend on the time of incubation. A pronounced effect of age of animals was observed with rat spleen homogenates. In mixed homogenates of liver and spleen, the production of hydrolytic products is slower than in pure spleen homogenates.

Sorbose-resistant mutants of Neurospora crassa, arising spontaneously or after nitrous acid treatment, can be mapped in at least 6 separate geneloci, scattered over the chromosome complement. Neither combined enzymatic optic tests, nor radio-paperchromatography give evidence for altered enzymes of sugar metabolism or gain of the ability to phosphorylate and utilize sorbose in these mutants. The increase of radioactivity of germinated conidia as a function of time of incubation with 14 C-labelled sorbose revealed that the mutants have a decreased rate of active (energy-dependent) sorbose uptake as compared to the wildtype. No difference in rate of either fructose or glucose uptake between mutants and wildtype could be found. Uptake of sorbose exhibited saturation kinetics for mutants and wildtype. K m values of the mutants were nearly equal to that of the wildtype; there are indications that V max is lowered in some of them. If supernatants of conidia of 2 mutants (sor r Α-1 and sor r B-57), mapping in separate linkage groups and thus representing two separate genes, were added to pregerminated wildtype conidia, their rate of sorbose-uptake was not depressed. These 2 mutants are therefore not of the excretor-type, i. e. they must be transport-defective mutants. Data available so far exclude that the mutants have a defect in a common carbohydrate carrier, or in a carrier specific for sorbose transport. It is concluded that mutants sor r Α-1 and sor r B-57 are permease-mutants, with genes A and B coding for 2 separate permeases or permease-subunits.

By using starch-gel electrophoresis the hemolymph proteins of metamorphosing queens and worker-ants of Formica polyctena were separated. By comparing the patterns thus obtained for 9 different developmental stages of the two female castes, it was shown that the electrophoretically separated fractions of queen and worker proteins are essentially the same whereas the distributionpattern of these fractions during metamorphosis is caste specific.

The method of STEWARD, LYNDON, and BARBER (1965) has been used, with some modifications, for the electrophoretic separation in acrylamide gel columns of soluble proteins from different root sections of pea seedlings. The influence of several experimental variables on the effectiveness of separation was studied. The results deviate from results already in the literature. Different catalyzers for gel polymerisation (β-dimethyl amino-propionitrile, N,N,N′,N′-tetramethylethylenediamine) have a small but detectable influence upon the separation. Fresh staining solutions (amido black 10 b) improve separations compared with repeatedly used ones, probably due to faster protein denaturation. Destaining of columns in the direction of protein movement renders better results than destaining in the opposite direction, since during destaining the protein bands shift slightly in the direction of destaining. Comparison of columns of the same proteins destained in each direction is useful. Dialysis against Tris-glycine-buffer (pH 8.3) prior to separation diminished the number of protein bands, to different extents depending upon the developmental stage of the root sections. The protein bands of older root segments changed the least. Protein solutions dialyzed against double distilled water and returned to buffer showed fewer bands which was probably the result of denaturation. Different storage times for frozen protein solutions (-20 ° C) as well as conditions during polymerisation of the acrylamide gel had effects on protein separation. In all cases proteins from older segments were more stable than those from younger segments. Comparison of our results with the literature shows that the quality of protein separation by disc electrophoresis in acrylamide is critically dependent upon methods of isolation and concentration of protein solutions. The upper limit of efficiency of the method seems to be about 30 protein bands at present.

The amino acid incorporation into protein by cell-free preparations of Chlorella pyrenoidosa is found to be stimulated by DNA isolated from various organisms. This stimulation is not affected by preincubation of the DNA with ribonuclease and by addition of ribonuclease to the reaction mixture. Streptomycin which reduces amino acid incorporation in the normal system stimulates slightly the incorporation in the presence of DNA. The incorporation rate is linearly dependent upon the amount of DNA in the reaction mixture from 10 to 100 µg DNA. Ribosomes from nitrogen-deficient cells exhibit a similar rate of stimulation by DNA. Deoxycholate-treated particles show much higher stimulation by added DNA than normal ribosomes do.