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ESR-Spectroscopic Detection of a [33S]-Sulfur Radical.

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has A,,
in ether at 336 m y (E approx. 4400) and 267 ( z approx. 8300), in chloroform at 343 (E approx. SOOO), and in nhexane at 335 m y (E approx. 4100). In accordance with the
H3C
H3C
R2
Base
CHz]; 2.30 [H(2), D, 52-3 =- 9.3 CPS]; 2.1-1.0 [H(3)-H(8),
MI; and 0.96 [H(9), Q, J9.s = 7.5 cps]; its ultraviolet and
N M R spectra correspond largely to those of protonated ( I )
in CF3COOH.
The salt (2) reacts with either sodiomalonodinitrile or sodiocyanoacetic ester in tetrahydrofuran at 20 "C t o form (3u) or
(3h) by elimination of ethanol.
CH3
-2
P
1 9
H3C
CH3
(41
( 3 ~ 1R
, = R' = CN
(5)
13bl, R ( R ' ) = C N , R'(H) = C 0 2 C 2 H 5
weak acidity of (4), compound ( 5 ) is a strong base: it
is extracted in the form of ( 4 ) from its solution in chloroform
by only 15 %, HC104.
I,,
The 6-phenyl-4-cyclopropenylbenzo[b]fulvenes(6) obtained
from (2) by condensation with 4-substituted benzaldehydes
(R = CI, C H 3 0 ) are not isomerized t o the corresponding
benzocalicene derivatives [I] under conditions which allowed
the prototropic conversion of the analogous cycloheptatrienylbenzofulvenes into the benzosesquifulvalenes [3].
Since no hydrogen-deuterium exchange was observed in the
three-membered ring of (6) in CH3OD/CH3ONa, it need
not be thermodynamic reasons that are responsible for the
lack of reaction.
[ Z 910/734 IE]
Received: January 14th and February lst, 1965
German version: Angew. Chem. 77, 258 (1965)
[ l ] D . Seip, Ph. D. Thesis, Universitat Freiburg/Brsg., 1965.
[21 A . Melera and U. Scheidegger, Varian Laboratory, Zurich
(Switzerland).
[31 H. Prinzbach and D . Seip, Angew. Chem. 73, 169 (1961).
Synthesis of 1-Dicyanomethylenephenaleneand
1-(Ethoxycarbonylcyanomethylene)phenalene
By Doz. Dr. H. Prinzbach and Dipl.-Chem. V. Freudenberger
Chemisches Laboratorium der Universitat Freiburg/Brsg.
(Germany)
For methylenephenalene (3), R = R = H ("phenafulvene"),
as for its vinylogues heptafulvene and triafulvene, a dipolar
resonance structure (4) is included in the quantum-mechanical
description of the ground state. We have prepared the first
stable derivatives of (3) by two routes.
1. Phenalen-1-one ( I ) [ l ] is alkylated in CHzC12 at 40 O C with
a n equimolar amount of triethyloxonium fluoroborate, giving
80-90% of the ethyloxonium fluoroborate (2), m.p. 170 to
171 O C (decomp.), Amax in acetonitrile = 408 m p (E = 14400),
N M R spectrum in nitromethane: 8 . 1 8 ~IT, CH3]; 5.0 [Q,
Angew. Chem. internat. Edit. / Vol. 4(1965)
1 No. 3
1 -Dicyanomethylenephenalene (3a) forms violet-red needles,
m. p. 236 O C ; its infrared spectrum has C = C absorptions at
1577 and 1626cm-1 and V C ~ Nat 2208cm-1; jts N M R
spectrum i n [2H,&dimethyl sulfoxide has signals at 2.64 T
[H(2), D, 52-3 = 9.0 cps]; 2.3-1.5 [H(3)-H(8), M J ; and 0.78
[H(9), Q , Jg-8 = 7.5 cps]; it has Amax in iso-octane at 45 I mp,
in acetonitrile a t 472 (E = 18800), and in ethanol at 476
(19000). The N M R and ultraviolet spectra reveal that, like
8,8-dicyanoheptafulvene [2] and the 4,4-dicyanotriafulvenes
[3], (3u) is not detectably protonated in CF3COOH.
1-(Ethoxycarbonylcyanomethylene)phenalene (36) is an
approximately 1 :1 mixture of the cis- and trans-isomers and
forms dark red needles, m.p. 135-137 OC; the infrared spectrum has C = C absorptions at 1570 and 1626 cm-1, VC=O
at 1695 cm-1, and V C ~ Nat 2193 cm-1; N M R signals are
observed in CDCI3 at 8.59/8.53 T p,CH3]; 5.89/5.65 [Q,
CH2]; 2.9-1.9 [H(2)-H(8), MI; and 0.76 [H(9), D, 59-8 =
7.5 cps]; A,,,
in iso-octane is at 463 mp, in acetonitrile
a t 482 (E = 11900), and in ethanol at 492 (11400). Compound (3b) is a stronger base than (3a), and in CF3COOH
the equilibrium ( 3 ) + (5) lies largely on the side of the
conjugate acid (5), judging from ultraviolet spectra.
2. Low yields of (3u) and (36) are also obtained by direct condensation of ( I ) in acetic anhydride at 100°C, with malonodinitrile and ethyl cyanoacetate, respectively.
The distribution of the x-electrons in (3n) and (3b) estimated
from the N M R data imply polarization of the molecules as
indicated i n (4).
Received: January 14th and February lst, 1965 [Z 909/733 IE]
German version: Angew. Chem. 77 (1965), in the press.
[ I ] G. Lock and G. Gergely, Ber. dtsch. chem. Ges. 77,461 (1944).
[2] K . Hafner, H . W. Riedel, and H . Danielisz, Angew. Chem.
75, 344 (1963); Angew. Chem. internat. Edit. 2, 215 (1963);
H. Prinzbach, Habilitation Thesis, Universitat Freiburg/Brsg.,
1962.
131 E. D . Bergmann and I. Agranat, J. Amer. chem. SOC. 86, 3587
(1964); A. S . Kende and P . T. Izzo, ibid. 86, 3587 (1964).
ESR-Spectroscopic Detection of a [33S]-Sulfur
Radical
By Dr. W. Rundel and Dr. K. Scheffler
Chemisches Institut der Universitat Tiibingen (Germany)
Free radicals can be detected by electron spin resonance
spectroscopy in solutions of 2,4,6-tri-t-butylthiophenol( I )
after irradiation with ultraviolet light; the radicals are stable
243
for some time at room temperature (tl/z ca. 30 min). The
g factor of 2.0104 and the absence of any hyperfine structure
in the ESR spectrum indicate that the unpaired electron is
located largely on the sulfur atom [ I ] . Participation of the
sulfur in the free radical state should be recognizable from the
hyperfine structiire in the ESR-spectrum of the radical
labelled with 33s 121.
Using a sample of ( I ) containing 11.5 %, 33S, we found in
addition to the main ESR signal (g = 2.0103 .L 0.0001) a
symmetrically distributed weaker quartet due to the interaction of the unpaired electron with the nuclear magnetic
33s isotope. The intensity ratio of the signals was 100:12,
corresponding to the ratio 33S/3?+34S(value calculated from
the isotope ratio:100:13). The quartet had a splitting constant a(33S) of 14.75 gauss at a line width of 2.8 gauss. This
proves that ( I ) is a genuine sulfur radical, most probably
the tri-t-butylphenyl sulfide radical [3].
To measure the ESR spectrum exactly, a solution in benzene
of labelled ( I ) and dibenzoyl peroxide was heated to 80 "C.
Under these conditions, a relatively large stationary concentration of the radicals is available for a long time [4].
Received: J a n u a r y 15th. 1965
[ Z 8961722 IE]
G e r m a n version: Angew. Chern. 77, 220 (1965)
Oxidation of ally1 chloride under analogous conditions led
to 1-bromo-3-chloro-2-propyl hydroperoxide (4), b. p.
61 ')C/O.I mm.
Similarly, methallyl chloride gave rise to cr-bromomethyl-achloromethylethyl hydroperoxide ( 5 ) , b. p. 56 OC/O.25 mm.
Received: J a n u a r y 18th. 1965 [ Z 897/723 I€]
G e r m a n version: Angew. Chem. 77, 219 (1965)
W . Bockeiniiller and L. Pfeuffer, Liebigs Ann. Chem. 537,
178 (1939).
121 Use of moist oxygen promotes thr reaction leading to (2).
1,2,3-Tribromopropane is formed in addition to (2).
[I]
Synthesis of Diethyldiselenophosphinic Acid and
Its Salts and Esters
By Prof. Dr. W. Kuchen and Dipl.-Chem. B. Knop
Institut fur Anorganische und Elektrochemie
der Technischen Hochschule Aachen (Germany)
Sodium diethyldiselenophosphinate (50) has been prepared
i n 80 %, yield [based on (4)J by the following route.
[ I ] W . Rrtndei and K . Scheff!er, 2. Naturforsch. 186, 984 (1963).
[2) Funds for purchasing the sulfur isotope were provided by the
Deutsche Forschungsgemeinschaft.
[3] Further experiments with a 13C-labelled benzene ring are in
progress to prove that the radicals are not-formed from liberated
sulfur.
[4] Subsequent processing of the mixture yielded some unchanged (1) plus bis(tri-t-butylphenyl) disulfide and benzoic acid.
Synthesis of Halogenoalkyl Hydroperoxides by
"Bromine-Induced Autoxidationc' of Ally1 Halides
By Prof. Dr. A. Rieche, Dr. Manfred Schulz. and
Dipl.-Chem. K. Kirschke
lnstitut fur Organische Chemie der Deutschen Akademie der
Wissenschaften ZLI Berlin, Berlin-Adlershof (Germany)
According to Bockemiiller and Pfcuffer [I], the simultaneous
action of oxygen and bromine on a solution in benzene of
ally1 bromide ( I ) at room temperature in diffuse daylight
produces the tetrabromodialkyl peroxide (3).
However, we have found that the reaction does not really
lead to (3), but to 1,3-dibromo-2-propyl hydroperoxide (2),
b.p. 66'C/0.1 mm, nL5 = 1.5493 [2]. Apart from (2), no
other peroxide could be detected either by paper- or thinlayer chromatography.
CH2=CH-CH2-Br
O,/Br2
CH2B r
I
FH-OOH
In o r d e l to obtain ( 5 ~ 1 )from ( 4 ) , a stoichiometric amount of
hydrogen selenide was passed into a solution of sodium
ethoxide in alcohol, which was then cooled i n ice, (4) being
added dropwise afterwards.
Dissolution of (5a) in acetone/H?O (95:5 v/v) and reprecipitatim with ligroin yielded the hydrate (C2H5)2P(Se)SeNa.
2 H 2 0 (5h) i n the form of stable colorless needles, m.p.
129- 130 'C.
When (56) was passed over a stronly acidic cation exchanger
[tonenaustauscher I from E. Merck, Darmstadt (Germany)],
aqueous solutions of diethyldiselenophosphinic acid
(C2Hs)~P(Se)Set-l( 5 ) were obtained which could be kept
for about 24 h at room temperature in the dark, but which
decomposed rapidly in diffuse daylight with precipitation of
elemental selenium.
Treatment of (56) with HCI gas i n benzene at 0 ° C also
produccd the free acid ( 5 ) in the form of a yellow oil;
however, because of the lability of ( S ) , this preparation is
not pure. It decomposes rapidly to bis(diethylse1enophosphoryl) selenide (6), colorless platelets, m.p. 65 "C, and
orange-red bis(diethylselenophosphory1) triselenide (7), m. p.
135-137OC [5]. Compound (6) was also made by heating
(4) with (5a) in benzene.
(CZHS)~P(S~)-(S~),-P(S~)(CZHS)~
( 6 ) , n = 1 ; (71, n = 3
Conversion of (2) into ( 3 ) could not be accomplished. Both
the reaction of (2) with acids and thermolysis of (2) yielded
1,3-dibromoacetone. Reduction of (2) with KI/acetic acid or
LiAIH4 afforded 1,3-dibromopropan-2-01.
FHzBr
CH-OOH
1
CH2Cl
(4)
244
C H3
CHzBr
I
-00 H
CH2Cl
7
IS)
When (5h) is refluxed with alkyl bromides, alkyl diethyldiselenophosphinates are produced, e.g. the ethyl ester, b. p.
105°C/0.13 mm, n 3 = 1.6193, and the n-propyl ester, b.p.
98 OC/O. 1 mm, n B = 1.6037.
Intramolecular coordination compounds of formula (8) are
precipitated from aqueous solutions of various metal salts by
addition of (56).
Complexes of this type include the zinc(I1) salt, m.p. 151 ' C ,
the cadmium(I1) salt, m.p. 158 "C, the lemon-yellow lead(I1)
salt, m. p. 157-158 "C, the brown-red palladium(I1) salt, m.p.
Angew. Chem. internaf. Edit.1 VoI. 4 (1965) No. 3
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33s, spectroscopy, esr, detection, sulfur, radical
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