close

Вход

Забыли?

вход по аккаунту

?

NSF3 as Ligand in Transition Metal Complexes (Thiazyl Trifluoride)pentacarbonylrhenium Hexafluoroarsenate.

код для вставкиСкачать
p - (q -Cyclopentadienyl)-p-[1-37-(2-methylallyl)] bis (triphenylphosphanepalladium) ( 2 a )
Triphenylphosphane (141 mg, 0.54mmol) in toluene (5 ml) was
added to a solution of C&17PdC5H5 (122mg, 0.54mmol)
in toluene (10ml) under nitrogen. The mixture was stirred
for 3 h at room temperature, the color changing from deep
red to orange. After removal of half the solvent and addition
of pentane (10ml) the mixture was kept at -30°C for 24h.
Orange-yellow crystals were formed; they were filtered, washed
with pentane and dried in .high vacuum. Yield 85 %.
Received: September 30, 1974 [Z 151 IE]
German version: Angew. Chem. 87,205 (1975)
[ l ] Part 17 of the series: Studies of the Reactivity of Metal x-Complexes.
This work was supported by the Schweizerischer Nationa1fonds.-Part 16:
Ref. [ 121.
Structural investigation^[^] on the complexes (2) and (3)
show a great similarity of the sulfur oxide difluoride imide
group with the isoelectronic thiazyl trifluoridel4I. It was already
known that NSF3 can function as a base toward very strong
Lewis acidsc5.6!
[7] Both the cyclopentadienyl and the methylallyl groups are disordered
in the crystal lattice; neither of them was taken into the refinement.
[XI The illustration shows an idealized arrangement of the cyclopentadienyl
and methylallyl groupsand not thedisordered centrosymmetricatom distribution in the crystal lattice. '
[9] Thecompound (C,H,HI)Pd,[P(C,H,),]2 described recently has the bond
lengths Pd-Pd=2.686 and Pd-P=2.278A [lo].
[lo] Y Kobayashi, Y. firoka, and H . Yamazaki, Acta Crystallogr. B 28, 899
( 1972).
[ l l ] G. Allegra, A. Immirzi, and L. Porri, J. Amer. Chem. Soc. 87, 1394
( 1965).
[12] H. Neukomm and H. Werner. Helv. Chim. Acta 57, 1067 (1974).
MFS
NSF:,
+
BF3
+
FSM*NSFs
(M
A S , Sb)
F3B * NSF:,
+
Re(CO)5Br
[ Re(CO)5NSF3]+ [ A s F s l -
(5)
(4)
[4] G . Parker and H . Werner, Helv. Chim. Acta 56. 2819 (1973).
[S] K. W e r e , A. P. f r a a f , and P. Cossee, J. Organometal. Chem. 12, 533
(1968); and literature cited therein.
[6] Crystal data: o=9.663(4), 6=9.725(4), c=10.863(3) A ; a=84.15(2),
p=81.01(2).y=72.32(3)"; Z=1;d,,,,=1.49gcm~3; Pi;2206reflections with
I >0.5 a(]);R =0.089 (Pd and P anisotropic).
+
Ag+AsF; can react quantitatively with Re(CO)5Br under pressure in NSF3 as solvent at room temperature in accordance
with the following equation:
Ag+AsF6-
[2] E. 0. Fischer and H. Werner, Chem. Ber. 95, 703 (1962).
[3] !l Harder and H. Werner, Helv. Chim. Acta 56, 549 (1973).
NSF:,
(6)
Reaction of ( 4 ) and ( 5 ) gives rise to the coordinatively unsaturated cation Re(C0): as intermediate; this reacts as acid
with the weakly basic solvent to give (6).
The thiazyl trifluoride complex (6) is a colorless, crystalline
solid which is stable at room temperature (decomposition
at 123°C); it has been characterized by elemental analysis
and 19F-NMR and IR spectra. The 19F-NMR spectrum (solution in SO2, CFCI3 int., room temperature) shows a singlet
at -60.8ppm (NSF,); the expected 1 : 1 : 1 : 1 quartet
(BF= +59.5ppm, JAsF=916Hz)is found for AsF;. The structure of compound (6) follows unequivocally from the IR
spectrum. The three absorptions [AI 2175 (m), E(2084 sh)
2057 (vs), A, 2010 cm- (s)] to be expected for C,, symmetry
of the central atom are observed in the C O region; these
Table 1. IR data [cm-'I of thiazyl trifluoride and a few of its coordination compounds
VSN
VSF
1515 m
811 vs
1650
950
1650
955
775 s
889
900
1636 m
900 sh
889 s
846 s
1637 m
882 s
838 s
1632 m
888 sh
876 s
830 s
[a] (7): [Mn(CO),NSF,] AsFh ; (8): [x-CpFe(C0)2NSF3] +AsF; ; preparation, properties, and structure of these
compounds will be published in Chem. Ber.
+
NSF, as Ligand in Transition Metal Complexes:
(Thiazyl Trifluoride)pentacarbonylrhenium Hexafluoroarsenate[-1
By Riidiger Mews and Oskar Glemsed']
We recently reported the preparation of the first transition
metal
complexes
containing
nitrogen-sulfur-fluorine
ligands['V *I.
M(CO),Br
+
-
AgN(S02F)2
-AgBr
M(CO),N(SOZF)~
( I ) , M = Mn, R e
M(C0)SBr
-~
['I
+
AgNSOFz
-AgUr
M(CO),NSOF2
(3), M = Mn, Re
Prof. Dr. 0. Glemser and Dr. R. Mews
Anorganisch-chemisches Institut der Universitat
34 Gottingen, Tammannstr. 4 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
186
are accompanied by the IR-forbidden B t at 2108 cm- (vw).
Because of the positive charge in (6) all bands are shifted
to higher wave numbers compared to the isoelectronic
Re(C05)NSOFztZ1.The frequencies of the NSF, ligands in
transition metal complexes are almost constant (cf. Table
1).
Compared with the free ligands the bands in the transition
metal complexes suffer less shift to higher wave numbers
than in the adducts with arsenic or antimony pentafluoridewhich seems reasonable in view of the acid strength. This
[ l ] R. Mews and 0 . Glemser, Z. Naturforsch. 286, 362 (1973); R. Frobose,
R. Mews, and 0. Glemser, to be published in Z. Naturforsch B.
[2] R. Mews and 0. Glemser, J. C. S. Chem. Comm. 1973, 823.
[3] B. Buss, D. Alteno, R. Mews, and 0. Glernser, to be published in J.C.S.
Chem. Comm.
[4] W H. Kirchhoffand E. 8. Wilson, Jr., J. Amer. Chem. Soc. 84, 334
( 1962).
[S] 0. Glemser and W Koch, An. Asoc. Quim. Argent. 59, 143 (1971).
[6] 0. Glemser, H. Richer?, and H. Hoeseler, Angew. Chem. 7 1 , 524 (1959);
0.Glemser and H . Richerr, Z. Anorg. Allg. Chem. 307, 318 (1961); A. Miiller,
0. Glemser, and K . Scherf, Chem. Ber. 99, 3568 (1965).
Angew. Chem. inrernat. Edif. i Vol. 14 ( 1 9 7 5 )
1 No. 3
comparison also shows that the ligand is bound to the central
atom via nitrogen.
E.uperimenta1
Equimolar amounts of ( 4 ) and ( 5 ) [2.2 and 3.0g (7.4mmol),
respectively] in NSFJ (10ml) are stirred for 12h at room
temperature in absence of light in a glass bomb furnished
with a teflon valve. The solvent is removed and the reaction
product (6) is dissolved in SO2 and separated from AgBr
by filtration. The yield is quantitative.
Received: December 23, 1974 [Z 170 IE]
G e r m a n version: Angew. Chem. 87.208 ( 1 9 7 0
C O N F E R E N C E REPORTS
Systems of Carbohydrate Utilization in Bacteria
By Kurr Wullenfils[*]
Utilization of carbohydrates of the nutrient medium as a
source of carbon for bacterial growth is subjected to genedependent regulation. Control loops exist for autocatalytic
enhancement of active transport, i. e. enrichment against a
concentration gradient, chemotaxis, and primary conversion
into metabolizable monosaccharides of their derivatives,
depending upon the signal emitted by the nutrient medium.
The best studied example is the lac system of E. coli which
optimizes utilization of natural P-gdlactosides-lactose or 2-R0-galactosylgl ycerol.
Galactosylglycerol has a chemotactic action on E . coli, and
is transported independently of the lac operon into the cell
where it induces the lac operon by interaction with the lac
repressor, so that synthesis of its dependent proteins is
enhanced i03 to 104-fold.-Lactose must first be converted
into allolactose (6-P-galactosylglucose) by the basal activity
of P-galactosidase; allolactose forms the inducer. Lactose is
then transported by lac permease, which is dependent upon
the lac operon.
The control loop can be split up, and the growth behavior
of the culture modified, by mutation in one of the genes
coding for repressor formation, for lac permease, for P-galactosidase, or for galactosylglycerol permease (studies with
B. Miiller-Hill and W. Boos).
[*] Prof. Dr. K. Wallenfels
Lehrst uhl .Biochemie. Chemisches Laboratorium d e r Universitat
78 Freiburg. Albertstrasse 21 (Germany)
With Aerobacter aerogenes, utilization of macromolecules such
as starch or pullulan is dependent upon an enzyme (pullulanase) which hydrolyzes the 1,6 bonds in these substrates.
This enzyme is localized on the exterior of the cell wall and
serves for the formation of cx- 1P-linked maltosaccharides
which migrate into the cell, presumably by active transport.
Their conversion into metabolizable monomers is accomplished by phosphorolysis or hydrolysis. Aerobacter phosphorylase has been isolated as a homogeneous protein and its
close relationship to the phosphorylases of eucaryotes established by determinations of molecular weight, pH optimum,
amino acid composition, and pyridoxal phosphate content.
The bacterial phosphorylase also degrades the reserve polysaccharide of the bacteria (aerobacter glycogen) but hardly affects
mammalian glycogen. Hydrolysis of the maltooligosaccharides
and -polysaccharides and of the 1,6 branching of the limit
dextrins of the bacterial glycogen is effected by two amylases
and a i,4- and i,6-specific glucosidase, which can be separated
by the trick of “substrate alienation”. The two amylases can
be distinguished in that one fraction (230000 dalton) cleaves
o-nitroe-phenyl glucoside, while the other (35000 dalton)
cleaves o-nitrophenyl a-maltoside. The third enzyme (86000
dalton) accepts maltose, isomaltose, saccharose, maltotriose,
and presumably other a-glucosyl oligosaccharides resulting
from amylopectin and pullulan degradation, as substrates.
The regulatory system for the bacterial utilization of starch
and similar polysaccharides as a source of carbon from the
external medium or from the internal reserves is considerably
more complex than the lac system, in keeping with the larger
number of enzymes involved (studies with H . Bender, P . Foldi,
G . Kurz, D. Linder).
Lecture at Kiel, December 19, 1974 [ V B 380 I€]
German version: Angew. Chem. 87, 139 (1975)
ABSTRACTS
A specific receptor protein is responsible for the primary
binding of each stimulant; further transmission of the various
primary stimuli to a common system is still a subject of
hypothesis. The duration of the “memory” for Salmonella
has been calculated as 1-10s. [Chemotaxis as a Model for
Sensory Systems. FEBS Lett. 40, S3-S9 (1974); 28 references]
[Rd 753 IE-R]
Chemotaxis as a model for sensory systems is discussed in
an article by D. E. Koshland J r . Bacteria, the simplest objects
ofstudy,do not respond to absolute concentrations ofstimulating substances, but to changes of concentration with time.
The life cycle of RNA phages is reported on by C. Weissmann.
Because of their smallness these phages are ideal model systems
suitable for the study of fundamental biological processes
at a molecular level. The article deals with the process of
187
Документ
Категория
Без категории
Просмотров
1
Размер файла
214 Кб
Теги
metali, nsf3, thiazyl, trifluoride, hexafluoroarsenate, transitional, complexes, pentacarbonylrhenium, ligand
1/--страниц
Пожаловаться на содержимое документа