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Atomic Reactions with Carbonylmetal Compounds.

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Table 2. Data for compounds (29) to (46).
Reaction
a
P
a
P
Ci
P
U
P
a
P
B
a
13
a
P
a
R
R'
R2
Yield (%)
M.p. ("C)
OH
OH
H
H
H
CH,
CH,
CH,
C,H,
C6H5
C,H,
H
H
p-CH3C,H,C0
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C6H4C0
p-CH,C,H,CO
p-CH,C,H,CO
p-CH,C,H,CO
17
5.3
2.8
23
8.2
5
29
12
156-158
[a1
[a1
154-155
[a1
H
H
OH
OH
OH
OH
NH2
NH,
OH
OH
OH
OH
OH
OH
NH,
NH*
H
CH,
CH,
C,H,
C,H,
H
H
H
H
H
H
H
H
H
P
[a1
185-190
155-160
[a1
132
127
145 (dec.)
155 (dec.)
180 (dec.)
160 (dec.)
189-191
160 (dec.)
200 (dec.)
200 (dec.)
156-157
[a1
18
6.6
77
32
75
71
61
90
65
60
1.6
0.6
[a] Amorphous.
[b] Formation, see text.
On reacting (8) with (14) we obtained, in addition to (31),
(32), and (32a), the isomeric N-3-mono(2-deoxy-~riboside) mixture of (45) and (46). Deacylation to the free
lumazine and isopterin N-l-(2-deoxy-~-ribofuranosides)
(37)-(44) was carried out by Zemplbn hydrolysis[41and
usually gave good yields of the desired product.
Received: August 24,1971 [Z 494e IE]
German version: Angew. Chem. 83,975 (1971)
[l] u( Pfleiderer, D. Autenrieth, and M . Schranner, Angew. Chem. 83,
971 (1971); Angew. Chem. internat. Edit. 10,928 (1971).
[2] L. Birkofer, A . Ritter, and H.P. Kiihltau, Chem. Ber. 97,934 (1964).
[3] E. Wittenburg, Chem. Ber. 101, 1095 (1968).
[4] G. Zemplin, H. Geres, and J . Hadacsy, Ber. dtsch. chem. Ges. 69,
1827 (1936).
Atomic Reactions with Carbonylmetal
Compounds[**I
By Karl H . Becker and Maria Schiirgers"]
Carbonylmetal compounds react rapidly in the gaseous
phase at low pressure with oxygen, hydrogen, or nitrogen
atoms to give electronically excited products which emit
characteristic spectra.
Because of their reactivity carbonylmetal compounds play
a significant role as catalysts in oxidation processes in
polluted atmospheres ; for example, the oxidation of NO
to NO, is accelerated considerably if slight amounts of
Fe(CO), are present"'. The presence of trace amounts of
carbonylmetal compounds in hydrocarbon-air mixtures
leads to either quenching of the hydrocarbon-air flames or,
at least, to substantial reduction of their flame velocities"';
as a consequence of this, Fe(CO), can be employed as an
antiknock agent in gasoline~'~!
We have investigated the reactions of Cr(CO),, Mo(CO),,
W(CO),, Fe(CO),, and Ni(CO), with oxygen, hydrogen,
and nitrogen atoms. The atoms were generated in a micro[*] Prof. Dr. K. H. Becker and Dr. M. Schurgers
Institut fur Physikalische Chemie der Universitat
53 Bonn, Wegelerstrasse 12 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft.
934
wave discharge and then mixed with the carbonylmetal
compounds in a reaction chamber. The total pressure in
the reaction chamber was a few torr, the partial pressure
of the carbonylmetal compounds lo-, torr at a flow rate
of 3 11s.
The chemiluminescence observed in the reactions owas
recorded with a spectral resolution of about AX= 10 A by
a detector arrangement consisting of a 1.5 m Czerny-Turner
monochromator and an EMI-9665-B photomultiplier.
Inspection of the spectra permits the following conclusions
to be drawn :
In reactions of carbonylmetals with oxygen atoms an
apparently continuous emission occurs which must
be assigned to a polyatomic emitter.
MO* emissions occur in all reactions of the type
M(CO), 0 except Mo(CO), 0.
+
+
Emissions ofexcited, neutral metal atoms M* are identifiable in the spectra of reactions M(CO), + 0 as well as
in those of the reactions M(CO), H and M(CO), N.
+
+
+
+
In the reactions Mo(CO), H and Mo(CO), N an
intense band system is observed at 5200 A which is
emitted by a diatomic molecule.
On the basis of reaction kinetics and spectroscopic data,
the continuum can be interpreted as emission from MCO* .
That the emissions occurring in all the reactions of carbonyl
metals with oxygen were due to CO; could be ruled out
because of the different low wavelength limits between
3000 %, and 4000%,.
MO* emissions are possibly due to direct formation
of this species from oxygen atoms and metal atoms.
Metal atoms are formed from carbonylmetal compounds
by stepwise degradation of the CO ligand with formation
of co,.
An explanation for the occurrence of metal atom emission
lines in all the reactions is that the metals do not lose, or
only partly lose, their valence energy, which they possess
as central atom in the carbonylmetal compounds, and
thus remain in an excited state. This assumption is supported
by the fact that (i) the same M* emission lines occur in
reactions of a carbonylmetal compound with different
atoms, and (ii) the excitation energies of the atoms observed,
Angew. Chem. internat. Edit. 1 Vol. 10 (1971) 1 No. 12
Cr*, Mo*, W*, and Fe*, are always less than the corresponding valence energy. A spectral analysis of the band
system, which, in the case of reactions Mo(CO), + H and
Mo(CO), N, occurs at 5200 A, indicates the presence of
a diatomic species having a very low bonding energy of
about 1.5 kcal/mol; quadratic dependence of the intensity
of emission on the Mo(CO), concentration suggests that
this system is to be assigned to an excited, weakly bound
Mo: species.
+
The rate constants for the overall reaction M(CO), +
atoms-rproducts were determined in a flow tube at a
linear flow velocity of 10 m/s. The intensity of chemiluminescence, which follows a first order reaction in the
presence of excess atoms served as indicator. The rate
constants of the light reaction M(CO), 0 were obtained
by comparison with the standard reaction NO + 0 -r
NO, + hvC4].All the rate constants are listed in Table 1.
anomeric mixtures could be obtained hitherto by conventional I3C-NMR spectroscopy. Development of the
new, more sensitive and more rapid recording technique
known as Pulse Fourier Transform (PFT) NMR spectroscopy has now made it also possible to study timedependent phenomena such as mutarotation by means of
13C resonance. Furthermore, the recording of the 'H
broad-band decoupling I3C spectra of reducing sugars
before and after mutarotation equilibrium has greatly
extended the scope of the previously used methods of I3C
signal assignment (comparison of the resonances with
those of other compounds, and off-resonance decoupling". 'I) in the investigation of carbohydrates.
YH,OH
+
Table 1. Rate constants in [I. mol-' s-'];
T = 298 K
Overall reaction
M(CO),
Lr(Lu),
Mo(CO),
W(CO),
Fe(CO),
I
H atoms
N atoms
Oa tom s
-
4.ux 1u2.9 x 10'
5.5 108
4.1x 1U"
1.9 x lo9
1.7 109
-
-
1 3.0 x lo8
1
bl
1
Light reaction
I
Oatoms
I a-3Ia-5
I l.>X I U
1
1.9 x lo7
3.8 x 10'
5.8 x lo7
Comparison of the rate constants of the overall reaction
M(CO), + 0 -+productswith those of the light reaction
M(CO), + 0 shows that a small percentage of the overall
reaction leads to formation of excited products.
Received: August 17, 1971 [Z 493 IE]
German version: Angew. Chem. 83,888 (1971)
[I] K . Wesfenberg, N . Cohen, and K . W Wilson, Science 171, 1013
(1971).
[2] G. Lask and H . Gg. Wagner, Symp. Combust. 8, 433 (1962); W J .
Miller, Combust. Flame 13, 210 (1969).
[3] H . Remy: Treatise on Inorganic Chemistry. Elsevier, Amsterdam
1956, Vol. 2, p. 289; N . !l Sidgwick: The Chemical Elements and Their
Compounds. Clarendon, Oxford 1950, Vol. 2, p. 1369; G. K . Rollefson
and M . Burton: Photochemistry and the Mechanism of Chemical
Reactions. Prentice-Hall, New York 1939, p. 362.
[4] A . Fontijn,C . B. Meyer, and H . J . Schiff;J. Chem. Phys. 40,64(1964).
Pulse Fourier Transform 3C-NMR Spectroscopy
of Mutarotating Sugars["]
By Wolfgang Voelter, Eberhard Breitrnaier,
and Giinther Jung"]
Routine measurement of the mutarotation of sugars by
13C-NMR spectroscopy has until now been hindered by
fundamental and instrumental difficulties[" : Although
the sensitivity of 13C resonance, which is relatively very
much lower than that of 'H resonance, can be improved
by accumulation of spectra with averaging computers
(CAT method, Computer Averaged Transitions), the unusually long accumulation times required are often unacceptable. Consequently, only the spectra of mutarotated
[*I
Priv.-Doz. Dr. W. Voelter, Priv.-Doz. Dr. E. Breitmaier
and Priv.-Doz. Dr. G. Jung
Chemisches Institut der Universitat
74 Tiibingen, Wilhelmstrasse 33 (Germany)
[**I Fourier-Transform-"C-NMR-Spectroscopy, Part 10.-Part 9:
W Voelter, G . Jung, E. Breitmaier. and R . Price, Hoppe-Seylers Z . Physiol. Chem. 352, 1034 (1971).
Angew. Chem. internat. Edit. 1 Vol. 10 (1971) J No. 12
$1I
a1
I
rn
-
90
I
-80
6 lpprni
I
-70
I
- 60
Fig. 1. PFT I3C-NMR suectra of D-glucose.
0.5 M in D,O. 512 Dukes.
pulse interval 0.8 s ; a) immediately, b) three days after preparation of
solution (ppm values negative w. r. t. TMS external=O).
The spectrum of a-D-glucose (Fig. 1a) shows five signals.
After adjustment of the mutarotation equilibrium ten
signals can be recognized (Fig. 1b) ([2]: eight signals). The
assignments of most signals are well known. The signal at
-95.70 ppm is ascribed to C-I of the p-anomer (equatorial
hydroxyl group) on the basis of the known downfield
shift1'-'] of about 4 ppm compared to that of C-I of the
a-anomer (axial hydroxyl group). The assignment of
p-C-3/p-C-5'21 (Table) arises since the signals of the y
carbon atoms C-3 and C-5 are displaced to lower fields
than the signal of the p carbon C-2 when the axial hydroxyl
group on C-I changes into an equatorial position. Comparison of the Figures 1a and 1b reveals that the crystalline
D-glucose used by us was present as the a-anomer.
D-Trehalose is formed by glycosydic coupling of two a-Dglucose residues. The influence of the glycosidic linkage
ought to be the least at C-4 and C-6; the ppm-values of the
signals of these carbon atoms are almost the same as those
of the corresponding carbon atoms of a-D-gluCOSe (Table).
In the disaccharide the signal of the anomeric carbon atom
(C-I) is displaced downfield by about 1.15 ppm from the
corresponding signal of a-D-glucose. Such downfield shifts
have also been established in the comparison of signals of
a free sugar with those of its m e t h y l g l y ~ o s i d e [ ~Since
~~].
the difference of the chemical shifts of C-2 of a-methyl+glucopyranoside and C-2 of a-methyl-D-glucose is less than
0.5 ppm, the C-2 (2') signal of trehalose (-72.35 ppm) can
be compared with the C-2 resonance of a-D-glucose
(-72.55 pprn). The signals at -70.85 and -71.90 then
belong to C-3 (3') and C-5 (5').
935
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