вход по аккаунту


Carbonylrhenium Clusters by Photoreaction of Re2(CO)10 with Water.

код для вставкиСкачать
are precipitated from the methanol solution by means of
ether. They decompose at 184°C; their solubility in methanol
is cu. 3 g/I.
Received: May 14, 1975 [Z 258 IE]
German version: Angew. Chem. 87,742 (1975)
CAS Registry numbers:
Sic12bipy*, 55853-1 1-7 : [SiCl zbipyz]Cl z, 55923-77-8 ; [SiCl &py 2](C104)2r
55925-19-4; [ S i ~ O M e ) ~ b i ~ y ~
[Si(OH),bipy2]2", 55853-13-9
[13 Part 6 of The Chemistry of Halosilane Adducts. This work was supported
by the Deutsche ForschungsgemeinschaR and the Fonds der Chemischen
Indust&--Part 5 : D. Kummer and H . Kdster, Z. Anorg. Allg. Chem.
402, 297 (1973).
D. Kttmmer and H . Kosfer, Z. Anorg. Allg. Chem. 398, 279 ($973).
S. Herzog and F. Krehs. Z. Chem. 8, 149 (1968).
MW (in H,O): exp. 221; calc. 610.27; A,=117.8 cm2/C2.mol (20"C),
mol/l in methanol.
r=2.93 x
A. G. MacDiarmid, personal communication.
D. Kummer and H . Kdster, Angew. Chem. 81,897 (1969): Angew. Chem.
internat. Edit. 8, 87X (1969).
~ ~ n y l r Clustas
h ~ i ~by
Re2(CO)lowith W a t e r [ * * ]
~ o t o r ~ e t i o nof
By Max Herberhotd and Georg S i i s s ~ ]
Decacarbonyldirhenium, Re,(CO)lo ( l ) , is stable towards
water even under drastic conditions; nor is it attacked by
dilute acids or bases"]. A "base reaction" can only be achieved
with methanolic potassium hydroxide, whereupon a dinuclear
complex K[Re,(CO),O,H] is formed[']. We have now found
that ( I ) reacts smoothly with H,O in aqueous ether under
photolytic conditions: the solution initially contains both the
known[31trinuclear hydrido complex [Re(CO),H] (2) and
an apparently tetranuclear hydroxo complex [Re(C0)3(0H)]4
(3). Species (2) is transformed into ( 3 ) under the reaction
conditions so that ( 3 ) is obtained exclusively if irradiation
is continued for a sufficient time.
pears in the case of solutions of ( 3 ) in deuterated solvents
(H/D exchange). The 'T-NMR
likewise exhibits
only one signal (6= 196.67 ppm in [D,]THF) which does not
split when the temperature i s lowered to - 80°C. This means
that all the C atoms in ( 3 ) are equivalent.
The hydrogen atoms in [Re(CO),(OH)], (3) can be reversibly replaced by d e u t ~ i u mwith D,O, the reaction product
being [Re(CO),(OD)], ( 4 ) (v(0-D) 2575 cm-I in KBr).
Reaction with diazomethane affords [Re(C0)3(0CH 3)]4 ( 5 )
which, in contrast to ( 3 ) , is sufficiently volatile for recording
a mass spectrum. This spectrum exhibits a molecular peak
somewhat above m/e 1200 (calc. 1200-1208) and a stepwise
loss of CO, CH30, and CH3 fragmentsr51.
While the relative molecular mass of ( 3 ) could not be
the mass spectrum of ( 5 ) indicates a tetrameric molecule. All findings are in accord with
the assumption that ( 3 ) , (4), and ( 5 ) have the structure
of tetranuclear, tetrahedral tricarbonylrhenium complexes(distorted cubane structure).
According to studies on the photolysis of Re,(CO),, ( I )
in CC14[71the initial step of the photoreaction appears to
be homolysis to give radicals Re(CO),. These reactive fragments probably then react with H20, either directly or after
loss of CO groups, to form polynuclear carbonylrhenium
Water (10ml) is added to a solution of Re,(CO),, ( I )
(0.33g, 0.5mmol) in diethyl ether (200mI) and the stirred
mixture irradiated for 15h with a high pressure mercury arc
(Hanovia S-200 W). The residue obtained from the ethereal
phase is washed with pentane to remove ( I ) and chromatographed in ether on acidic alumina. The colorless eluate affords
is recrystallized from ether/pen[ R e ( C O ) ~ ~ 0(~3~) which
tane (1 : 2) and dried at 80°C in a high vacuum: yield 0.16g
(53 %f; dark coloration > 160°C, decomposition ~ 3 5 0 ° C .
Received: June 16, 1975 [Z 271 IE]
German version: Angew. Chem. 87.710 (1975)
CAS Registry numbers:
(11, 14285-68-8; 13). 56553-73-2; ( 5 ) . 56553-72-1
W Hieber and H . Fuchs, Z. Anorg. Allg. Chem. 248, 256 (1941).
W Hieber and L. Schusier, Z. Anorg. Allg. Chem. 285, 205 (1956).
D. K. Huggins, W Fellmann, J . M . Smith, and H . D. Kaesz, J. Am.
Chem. SOC.86.4841 (1964).
Bruker HFX 90; measurements by Dr. C. G. Kreiter.
Atlas CH4, ion source T 0 4 ; measurements by Dr. J. Muller.
Osmometric measurements lead to contradictory results for complexes
olsimilar type: they also fail in the case of (31 because of its insuficient
solubility. The method according to Rast (camphor) likewise failed to
give unambiguous results.
M . Wighton and D. Bredesen, J. Organometal. Chem. 50, C 3 5 (1973).
All operations carried out under N,.
(3), R = H
(4), R = D
(S), R = OCH3
The new hydroxo complex ( 3 ) is colorless, air-stable, and
nonvolatile in a high vacuum. The simple IR spectrum suggests
a highly symmetri~lstructure; in addition to the absorption
bands of a tricarbonyl group ( v ( C r 0 ) 2021 (s) and 1919
(vs)cm- in THF), a sharp double band (v(0-H) 3550 min KBr) is observed. In the 'H-NMR spectrum (diamagnetic)
just one broad singlet at S=6.50 ppm in [D6]acetone is found
which corresponds to the hydroxy protons and slowly disap-
p] Doa. Dr. M. Herberhold and DipLChem. G. Suss
Anorganisch-chemisches lnstitut der Technischen Universitat
8 Munchen 2, Arcisstrasse 21 (Germany)
p * ] This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie. G . indebted to the Studienstiftung des Deutschen Volkes for a postgraduate grant.
A New Route to Epoxides
By D. Vun Ende, Willy ~ u ~ n o nand
t , Aluin Krief
We recently described a synthon which allows the epoxide
synthesis from phenyl selenoacetals and carbonyl compounds[']. Further investigations have demonstrated that the
use of methyl selenoacetals offers several advantages (Scheme
I), the main ones are listed below:
DipLChem. D. Van Ende. Dr. W. Dumont, and
Prof. Dr. A. Krief [**I
Department de Chimie, Facultes Universitaires d e Namur
61, rue de Bruxelles, B-500 Namur (Beigium)
[**I On leave from CNRS (France).
Angew. Chem. internat. Edit. J Vol. 14 ( 1 9 7 5 ) J No. 10
Без категории
Размер файла
161 Кб
photoreactive, water, clusters, carbonylrhenium, re2
Пожаловаться на содержимое документа