вход по аккаунту


Book Review Die komplexometrische Titration (Complexometric Titration). Volume 45 of УDie chemische AnalyseФ (Chemical Analysis). By G. Schwarzenbach and H. Flaschka

код для вставкиСкачать
redox potential E’o at p H 7.0 and 25 “ C is -0.057 V (ferredoxin: -0.41 V); only one electron is given up on oxidation
(as in ferredoxin). Like ferredoxin and thioredoxin, rubredoxin contains many more acidic amino acids than basicones :
12 Asp, 6 Glu, compared with only 4 Lys. N o specific reactions of rubredoxin have been found as yet. It catalyses the
ferredoxin-catalysed reactions (e.g . the reduction of NADP
by hydrogen and hydrogenase), but the reaction rates are
only about 20 % of those obtainable with ferredoxin. / Proc.
nat. Acad. Sci. USA 54, 193 (1965) / -Ha. [Rd 414/623 IE]
Fulvene containing less than 2 % of impurities is formed in
74 % yield when a mixture of the acetoxymethylcyclopentadienes ( I ) and (2) is allowed to react with the equivalent
quantity of triethylamine. H. Schaltegger, M . Neuenschwander, and D . Meuche prepared ( I ) and (2) from cyclopentadienylsodium and chloromethyl acetate in tetrahydrofuran
~ C H ~ - O - R
P H 2 - O -
(I), R = -CO-CH3
( 3 ) , R = -CH3
(2), R = -CO-CH3
( 4 ) , R = -CH3
at -30 “ C (yield 30 %). N o fulvene is obtained from a mixture
of (3) and (4) under the same conditions. / Helv. chim. Acta
48, 955 (1965) J -Bu.
[Rd 437/646 IE]
The biosynthesis of the biotin enzymes from apoenzyme and
biotin has been studied by Th. Hopner and J. Knappe. They
used the P-methylcrotonyl-CoA carboxylase from Achromobacter 1Vs-W. Even under oprimal growth conditions, this
biotin-auxotrophic organism (grown with isovaleric acid as
the only source of carbon) synthesizes a p-methylcrotonylCoA carboxylase in which only 80 to 9 0 % of the active
centers are occupied by biotin. In the presence of a holocarboxylase synthetase which had been concentrated by a
factor of 150, the remaining apo-centers could be saturated
with biotin, this saturation being accompanied by stoichiometric regeneration of carboxyl reactivity. The course of the
reaction [Equations (1) and (2)] was demonstrated by the
following synthetase-catalysed reactions:
biotin + ATp r-=.
biotinyl -AMP pyrophosphate
biotinyl - A M P S apoenzyme
holoenzyme + AMP (2)
a) ATP-dependent formation of biotin hydroxamate from
biotin and hydroxylamine; b) biotin- and hydroxylaminedependent formation of AMP from ATP; c) biotin-dependent exchange between ATP and 3*P-pyrophosphate;
d) synthesis of ATP from biotinyl -AMP and pyrophosphate;
e) incorporation of biotin from biotinyl -AMP into P-methylcrotonyl-CoA carboxylase. / Biochem. Z . 342, 190 (1965)
[Rd 415,’624 IE]
Cyclooctatetraen (Cyclooctatetraene). By G. Schroder. Monograph No. 73 to “Angewandte Chemie” and “Chemie-Ingenieur-Technik”.VerlagChemieGmbH.Weinheim/Bergstr.
1965. 1st Edit.,viii
88 pp.. many illustr., cardboard
DM 23.- (about $6.-).
In recent years cyclooctatetraene has been the subject as well
as the starting material of a large number of investigations,
and these are comprehensively covered in this monograph. A
description of the syntheses and a short chapter on the structure is followed by much the longest section, which is devoted
to the chemical properties of eyclooctatetraene and its derivatives. The following are discussed in detail: reduction and
oxidation products of cyclooctatetraene, its behavior towards
acids, bases, and free radicals, the adducts formed with
carbenes, halogens, and dienophiles, its organometallic complexes, valence-bond isomers, substitution products, and
dimers with particular emph sis on bullvalene (obtainable
from them). Finally there are selected recipes for preparation
of 20 derivatives. The authm restricts himself to short but
clear restatement of the literature, which is considered up to
the middle of 1964. Yet owing to the modernity ofthe subject,
several sections already need expansion or correction (inversion of cyclooctatetraene, its bromination, and the structure of the dimer of m.p. 53 “C). Anyone interested in the unusually varied chemistry of cycloctatetraene will find this
volume an ideal source of information. Unfortunately the
price of this little book is not in proportion to its size.
W. Roth
[NB 461/314 IE]
Die komplexometrischeTitration (Complexometric Titration).
Volume 45 of “Die chemische Analyse” (Chemical Analysis). By G. Schwarzenbach and H. Flaschka. Ferdinand
Enke Verlag, Stuttgart 1965. 5th revised Edit., xvi+ 339
pp.. 42 figs., 12 tables, 48.- D M (about$ 12.-).
The present fifth edition of this part of “Diechemische Analyse” (Chemical Analysis) appears 20 years after the introduction of complexometric titration and 10 years after the first
edition. Written in collaboration with H. Fluschka it has become a completely new book. The volumetric procedure
established by G. Schwarzenbach is characterized by the use
of specific complex-formers and indicators for metal ions, and
its explosive development has necessitated an expansion of
the text from 119 to 339 pages. Division of the text into two
parts of equal length - one theoretical and the other practical - has been maintained. The first part contains general
information about titration reagents, the theory of the course
of the reactions and the mode of action of dye and fluorescent
indicators in complexometry, the methods of visual and
instrumental end-point determination and the various types
of titration, their accuracy and selectivity. In the second part
practical details are given, first for the preparation of volumetric and indicator solutians, then for complexometric
determination of almost all the elemnts; in the last section
is described the determination and masking of metals in a
most imaginative way by manifold combinations of formation
and fission of kinetically labile metal complexes. (The determination of non-metals, e.g. fluorine, should, however, be
considered critically.) The literature up to the end of 1963 is
cited in 1437 references, arranged alphabetically in groups according to the year of their appearance.
In its new expanded form this book has become the standard
work for complexometric titrations. It is a valuable adviser
for analytical practice and is exciting reading for all who are
interested in the theoretical foundations of chemistry in aqueous solutions.
F. See2
[NB 463/316 IE]
Boron-Nitrogen Compounds. Vol. VI of the Series “Anorganische und allgemeine Chemie in Einzeldarstellungen”. By
K . Niedenzu and J. W. Dnwson. Springer-Verlag, BerlinHeidelberg-New York 1965. 1st Edit., viii + 176 pp.,
numerous figs., linen 27.- DM (about $7.-).
Several books have recently appeared on the chemistry of
boron. The present one concerns boron-nitrogen compounds,
which have been extensively studied during the last 10 years
or so, and to which the authors have made numerous contributions. Six chapters are devoted to amine-boranes (borazanes), aminoboranes (borazenes), borazoles, BNC heterocycles, and boron nitrides. Additionally there is a short section on IlB nuclear magnetic resonance. Numerous tables
Angew. Chem. internat. Edit. j Vol. 5 (1966)
No. 4
Без категории
Размер файла
146 Кб
komplexometrische, flaschka, die, complexometric, chemische, analyse, schwarzenbach, volume, titration, chemical, book, analysis, review, уdie
Пожаловаться на содержимое документа