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Identification of Butatrienedione Its Radical Anion and Its Radical Cation in the Gas Phase.

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(200 mL) was acidified with 3 drops of 32% HCI and stirred for 15 min at 50°C
(exclusion of light). After extraction with CH,CI,, the organic phase was dried
(Na,SO,) and purified on silica gel (20 8). After removal of the solvent there
remained 0.53 g (72%) of a crystalline product. For further purification the
substance was recrystallized from CH,CI,/Et,O; yield 0.42 g (57 %), colorless
platelets. M.p. 135- 137 "C (decomp.), noticeable decomposition above 120 "C.
256 nm (4.37), 288 (4.011, 311 (3.51), 340 (3.55). IR
UV (CH,CI,): ,I,
(KBr): 3 = 2160cm-', 2135, 1755, 1685, 1355, 1355, 1310, 712. MS (70eV):
m / z (%) = 164 (9,Me), 136(7), 80(86), 68(69), 52(100). Correct elemental
8: A mixture of dihydropyran-2,4,6-trione
[17] (0.60 g, 4.7 mmol) and 2-az1do3-ethylbenzothiazolium tetrafluoroborate [16] (3.00 g, 10.3 mmol) in 150 mL of
100 % glacial acetic acid was stirred for 2 h at 60 "C. The crude desired product
was precipitated by addition of 180 mL of Et,O. After filtration the crystalline
residue almost completely dissolved in CH,CI,/CH,CN (4: 1) and was purified
chromatographically on silica gel with CH,CI, as eluent. Evaporation of the
liquid phase to dryness furnished a crystalline residue, which was dissolved in
60 mL of CH,CI, and 20 mL of CH,CN. Subsequent dropwise addition of
250mL of Et,O and filtration afforded 0.31 g (36%) of colorless platelets.
Noticeable decomposition above 150°C. UV (CH,CI,): A,, (Ig E ) = 244 nm
(4.23, 258 (4.281, 268 (4.27), 280 (4.24). IR (KBr): V = 2170cm-', 2100, 1750,
1740, 1715,1640,1355,740,735. MS(70eV).m/z(%) = 180(30,M@),80(10),
68(39), 52(100). Correct elemental analysis.
Received: March 5,1990 [Z 3830 IE]
German version: Angew. Chem. 102 (1990) 920
[l] G. Maier, H. P. Reisenauer, U. Schafer, H. Balli, Angew. Chem. 100(1988)
590; Angew. Chem. Inf. Ed. Engl. 27 (1988) 566; see also: F. Holland, M.
Winnewisser, G. Maier, H. P. Reisenauer, A. Ulrich, J. Mol. Spectrosc. 130
(1988) 470.
[2] a) J. J. Bloomfield, I. R. S. Irelan, A. P. Marchand, Tetrahedron Lett. 1968,
5647. The bridged 1,2-diones described in this work have already been
irradiated by us in an argon matrix in a previous study (unpublished
experiments, 1979), and only CO was found. b) H.-D. Scharf, R. Klar,
Tetrahedron Lett. 1971, 517; c) J. Strating, B. Zwanenburg, A. Wagenaar,
A. C. Udding, ibid. 1969,125; d) D. Bryce-Smith, A. Gilhert,J. Chem. Soc.
Chem. Commun. 1968,1319; e) D. L. Dean, H. Hart, J Am. Chem. Sac. 94
(1972) 687; 9 M. B. Rubin, M. Weiner, H.-D. Scharf, ibid. 98(1976) 5699.
[3] The existence of the analogous carbon sulfides C,S, and C,S, has been
confirmed mass spectroscopically: D. Sulzle, H. Schwarz, Angew. Chem.
fOO(1988) 1384; Angew. Chem. Int. Ed. Engl. 27(1988) 1591; Chem. Ber.
122 (1989) 1803. Nole added i n proof: In the meantime we have generated
C,S, via an independent route, and isolated it in an argon matrix. Conversely, H. Schwarz and D.Siilzle have detected C,O, by neutralizationreionization mass spectrometry (private communication, April 30, 1990).
(41 a) G. P. Raine, H. F. Schaefer 111, R. C. Haddon, J Am. Chem. Sac. 105
(1983) 194, b) R. C. Haddon, D. Poppmger, L. Radom, &id. 97 (1975)
1645; c) R. C. Haddon, Tetrahedron Lett. 1972, 3897; d) J. Fleischhauer,
M. Beckers, H.-D. Scharf, ibid. 1973, 4275; e) P. Lindner, Y Ohm, J. B.
Sabin, I n ! . J. Quanrum Ckem. Symp. 7(1973) 261 ; 9 R. D. Brown, E. H. N.
Rice, J Am. Chem. Sac. 106 (1984) 6475.
[S] F. Henle, Justus Liebigs Ann. Chem. 350 (1906) 344.
[6] a) R. L. DeKock, W. Weltner, Jr., J. Am. Chem. Sac. 93 (1971) 7106;
b) R. D. Brown, F. Eastwood, P. S. Elmer, P. D. Godfrey, thid. 105 (1983)
6496; c) R. D. Brown, P. D. Godfrey, P. S. Elmer, M. Rodler, L. M. Tack,
ibid. 107 (1985) 4112; d)R. D. Brown, D. E. Pullin, E. H. N. Rice, M.
Rodler, ibid. 107 (1985) 7877.
171 J. J. P. Stewart, J. Comput. Chem. 10 (1989) 209, 221.
[8] H. J. Werner, W Meyer, J. Chem. Pkys. 74(1981) 5794; H. J. Werner, E. A.
Reinsch, ibid. 76 (1982) 3144.
[9] J. S. Binkley, M. J. Frisch, D. J. DeFrees, R. Krishnan, R. A. Whiteside,
H. B. Schlegel, E M. Fluder, J. A. Pople: GAUSSIAN 82, CarnegieMellon University, Pittsburgh 1982.
[lo] E. Wasserman, L. C. Snyder, W. A. Yager, J. Chem. Phys. 41 (1964) 1763.
[ l l ] a) R. J. Van Zee, G. R. Smith, W. Weltner, Jr., J. Am. Chem. Sac. 110 (1988)
609; b) D. W. Ewing, ibid. 111 (1989) 8809.
[12] R. J. Van Zee, R. F. Ferrante, K. J. Zeringue, W. Weltner, Jr., D. E. Ewing,
J. Chem. Phys. 88 (1988) 3465
[I31 a) E. Wasserman, L. Barash, W. A. Yager, J. Am. Chem. Sac. 87 (1965)
2075; b) G. R. Smlth, W. Weltner, Jr., J Chem. Phys. 62 (1975) 4592.
[14] R. R. Lemhke, R. F. Ferrante, W. Weltner, Jr., J. Am. Chem. Sac. 99(1977)
1151 J. H. Boothe, R G. Wilkinson, S. Kushner. J. H. Williams, J. Am. Chem.
Soc. 75 (1953) 1732.
[16] H. Balli, F. Kersting, Justus Liebigs Ann. Chem. 647 (1961) 1.
[17] R. Kaushal, J. Ind. Chem. Sac. f7(1940) 138.
c) VCH Verla~sgesell.scliaflmhH, 0-6940 Weinheim, 1990
Identification of Butatrienedione, Its Radical Anion,
and Its Radical Cation in the Gas Phase**
By Detlev Siilzle and Helmut Schwarz*
Dedicated to Professor Wolfgang Kirmse on the occasion
of his 60th birthday
There are several reasons for the exceptional interest"] in
linear and quasi-linear cumulenes of the general structure
XC,Y (X,Y = lone pair, H,, 0, S; n 2 2). The compounds,
some of which have been postulated as key intermediates in
the formation of interstellar species, possess unusual spectroscopic properties, and their reactivity/stability, as well as
their electronic ground state (singlet versus triplet), is governed by an "even/odd alternation". Although many combinations of XC,Y have long been known for n = 3, 5, the
even-numbered analogues (n = 2, 4, 6) have often eluded
unambiguous experimental identification. However, this situation is not due-as originally assumed 12]-to an intrinsic
instability of these curnulenes, but rather must be the result
of fast bimolecular reactions. For example, the dithiocumuand also the mixed S/O cumulenes SC,S (n = 2,4, 6)r1.3,41
lenes SC,0[51 and SC,0161 have been identified in the gas
phase by neutralization-reionization mass spectrometry
On the other hand, all attempts so far to prepare and
characterize even-numbered cumulenediones OC,O (n = 2,
4, 6) have been unsuccessful. Although ethylenedione,
OC,O, for example, is expected to be a kinetically extremely
stable triplet on the basis of ab initio calculations,[*]from the
earlier attempts of S t a ~ d i n g e r [to
~ ] this day no group has
succeeded in generating and identifying this
Here we report the generation of the radical anion, radical
cation, and neutral molecule of butatrienedione, OC,O, in
the gas phase. These experiments complement the recent matrix studies of Maier et a1.I' l l
to 1[13] affords an
Dissociative electron
intense signal at m / z 80, which corresponds to a compound
having the elemental formula C,O?@. Mass selection of
C,Of@ via B(1)E and subsequent collisional activation of
the 8-keV ion beam (collision gas 0,; 80% transmission 7 )
afford the collisional activation (CA) spectrum shown in
Figure 1 a. All anionic decomposition products in Figure 1 a
can be explained by direct bond cleavage in 20e. The assignment of the connectivity OCCCCOoe to C,O?@ is supported by the fact that the tendency to undergo skeletal rearrangements is appreciably less for radical anions than for
Accordingly, we conclude that loo eliminates CO, and (CH,),CO and is transformed into 20°
(Scheme 1). We further maintain that, except for COO'
(whose electron affinity (EA) is negative), all other species
(C,O,, C,O, C,O, C,O, C,, C,, and C,) must have positive
EA values.
Subjection of 20° in a further collision experiment to a
vertical charge reversal (CR)['4b, 16] results in the spectrum given in Figure 1 b. This spectrum contains an intense
"recovery signal" for C,Oye and establishes that not only
C,Ofe but also C,0Ye exists in a potential minimum.
Again remarkable is that, typical for a cumulene structure
20°, decomposition occurs via cleavage of individual bonds.
[*] Prof. Dr. H. Schwarz, DipLChem. D. Sulzle
Institut fur Organische Chemie der Technischen Universitat
Strasse des 17. Juni 135, D-1000 Berlin 12
This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen Industrie, and the Graduiertenkolleg Chemie
0S70-0833190/0808-0908$3.50+ ,2510
Angew. Chem. Int. Ed. Engl. 29 (1990) N o . 8
shown in Figure I d . Noteworthy features include (1) the
unusually intense recovery signal, which indicates favorable
Franck-Condon transitions, and (2) the excellent agreement
with the NR spectra generated under various conditions.
This finding can also be viewed as evidence for comparably
minor structural changes in the system 20° -+ 2 + 2 O @ .
Summary: Neutral butatrienedione, its radical anion, and
its radical cation are perfectly stable molecules. If still further
evidence were needed for this claim, it would be provided by
an independent tandem experiment. If the reionized C,OF@
formed via the sequence 2 O @ -+2+2'@ is again mass-
C02 ; - ( C H h C O
Scheme 1
selected and subjected to collisional activation, the resulting
interference-free NR spectrum is identical with the CA spectrum of 2 O @ generated by direct collisional activation.
:'" ;c
Received: May 17, 1990 [Z 3962 IE]
German version: Angew. Chem. 102 (1990) 923
Fig. 1. a) CA spectrum of C,Oye (collision gas O,, 80% T ) ;b) CR spectrum
80% T ;0,, 80% T ) ;
ofC,Ope (Oz, 80% T);c) NR spectrum ofC,Ope (02,
d) NR spectrum of C,Ope (Xe, 70% T ; 0,, 80% T).
Is it possible to prepare neutral butatrienedione (2) from
the radical anion 20° and/or radical cation 2 O @ (also accessible by direct 70-eV electron-impact ionization of 1) by electron transfer and to characterize 2 in an NRMS experiment?
As revealed by Figure 1 c, the answer is unequivocally yes.
Oxidation of 20° generates 2, which is further oxidized to
2 O @ (Fig. 1 c). Analogously, reduction of 2 O @ yields 2,
which, upon subsequent reionization, affords the spectrum
Angew. Chem. I n [ . Ed. Enxl. 29 (1990) No. 8
[l] Detailed report: D. Siilzle, N. Beye, E. Fanghanel, H. Schwarz, Chem.
Ber., in press.
[2] F. A. Cotton, G. Wilkinson: Advanced Inorganic Chemistry, Interscience
Publisher, New York 1962, p. 226; L. D. Brown, W. N. Lipscomb, J. Am.
Chem. Soc. 99 (1977) 3968.
[3] D. Siilzle, H. Schwarz, Angew. Chem. 100 (1988) 1384; Angew. Chem. Int.
Ed. Engl. 27 (1988) 1337.
[4] D. Sulzle, H. Schwarz, Chem. Ber. f22 (1989) 1803.
[5] D. Siilzle, J. K. Terlouw, H. Schwarz, .f Am. Chem. Sac. 112 (1990) 628.
[6] D. Siilzle, H. Schwarz, unpublished.
[7] Review articles: Wesdemiotis, F. W. McLafferty, Chem. Rev. 87 (1987)485;
J. K. Terlouw, H. Schwarz, Angew. Chem. 99 (1987) 829; Angew. Chem.
I n f . Ed. Engl. 26 (1987) 805, H. Schwarz, Pure Appl. Chem. 61 (1989) 685,
J. K. Terlouw, Adv. Mass Spectrom. if (1989) 984; J. L. Holmes, Mass
Spectrom. Rev. 8(1989) 513; E W. McLafferty, Science (Washington D.C.)
247 (1990) 925.
[S] G. P. Raine, H. F. Schaefer 111, R. C. Hadders, J. Am. Chem. Soc 105
(1983) 194.
191 H. Staudinger, G. Anthes, Ber. Dtsch. Chem. Ges. 46 (1913) 1426.
[lo] For references, see [5].
1111 G. Maier, H. P. Reisenauer, H. Balli, W. Brandt, R. Janoschek, Angew.
Chem. 102 (1990) 920, Angew. Chem. Int. Ed. Engl. 29 (1990) 905.
[12] All experiments were carried out with a four-sector mass spectrometer in
the arrangement BEBE under standard conditions (B, magnetic sector; E,
electric sector). NH, (p = lo-' torr) is used as an electron moderator.
[13] H. R. Snyder, C. W. Kruse, J. Am. Chem. Sac. 80 (1958) 1942.
[14] a) H. Budzikiewicz, Angew. Chem. 93 (1981) 635; Angew. Chem. In!. Ed.
Engl. 20 (1981) 624; b) J. H. Bowie, Mass Spectrom. Rev. 3 (1984) 161.
1151 K. Levsen, H. Schwarz, Mass Spectrom. Rev. 2 (1983) 77.
[16] J. H. Beynon, Pror. Royal Soc. London Ser. A 378 (1981) 1.
Verlagsgesellschaft mhH. 0-6940 Weinheim, 1990
0570-0833190/0808-09093 3 . 5 0 t 2510
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anion, identification, gas, radical, cation, phase, butatrienedione
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