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Novel Chlorooxoaluminates.

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From the I3C-NMR spectrum of 3-2Li empirically derivable charges pemp[lgdl
are obtained which are in good
agreement with the calculated M N D O charges of 3”. A
comparison of the 6(I3C)- and p,,,-values of the two dianions shows that the electron density distributions in the
cyclic 3-2Li and in the acyclic 5-2Li are almost the same.
Furthermore, in 3-2Li only about 48% of both charges appear in the benzocyclobutene moiety. Thus, a preferred
cyclic delocalization with formation of an aromatic
(4n 2) 71-electron system is not observed in the case of 32Li.
Analysis of the ‘H-NMR spectrum using a method described by Giinther et al.[20d1,
in which the benzene ring in
3-2Li serves as a probe for the properties of the attached
annulene, led to the same result. Thus, the “Alternanzparameter” Q for 3-2Li (1.05) is reconcilable only with a n
“olefinic” and not with an “aromatic” nsystem in the
four-membered ring.
The low acidity of 2-Li, the electron distribution in 32Li, and the Q-value of 3-2Li preclude the latter dianion
being designated as an aromatic compound. 3-2Li is preparable because the negative charges are largely taken over
by the substituents. This reduces unfavorable electron repulsion in the four-membered ring.
+
Received: September 4, 1981 [Z 985a IE]
German version: Angew. Chem. 94 (1982) 141
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982. 345-354
121 Summary: P. J. Garratt in S. D. Barton, W. D. Ollis: Comprehensive Organic Chemisfry. Pergamon Press, Oxford 1979, Vol. I, p. 215 and 361.
[71 G. Maier, F. Kohler, Angew. Chem. 91 (1979) 327; Angew. Chem. Inf.
Ed. Engl. I8 (1979) 308 (and further references cited therein and in
[ 11).
[I91 d) H. Baumann, H. Olsen, Helv. Chim. Acfa 63 (1980) 2202.
1201 d) H. Giinther, M. E. Gunther, D. Mondeshka, H. Schmickler, F. Sondheimer, N. Darby, T. M. Cresp, Chem. Ber. 112 (1979) 71.
The Dianion 1,2,3,4-Tetraphenylcyclobutadienediide””
By Gernot Boche*, Heinz Etzrodt, Michael Marsch, and
Walter Thiel
Lack of information on the cyclobutadienediide dianion
(cf. [’I) induced us to re-attempt the synthesis of the tetraphenylcyclobutadienediide dianion 520121.
In the following
communication we report on the access to and the properties of 5-2K.
Previous attempts‘’] to prepare 5-2M from cis-1 and
bases (BQMQ) had led with n-BuLi in tetrahydrofuran
(THF) to the stable lithium salt of the monoanion 2-Li,
and with KOtBu in dimethyl sulfoxide via 3-K to 4. Reaction of cis-1 with KOtBu or lithium dicyclohexylamide in
T H F had afforded 4 via trans-1. The same was observed
with lithium diisopropylamide, lithium tert-butylcyclohexylamide and lithium tetramethylpiperidide in T H F ; nBuLi/tetramethylethylenediamine and tBuLi in THF, on
the other hand, led to 2-Li and to addition of base at the
stilbene double bond.
Only the strongest base known at present, namely
(CH3)3SiCH2K151,
in T H F led to 5-2K. Reaction with D 2 0 ,
giving dideuterio-cis- and dideuterio-trans-1 proved the
presence of the dianionic four-membered ring. This ruled
[*] Prof. Dr. G. Boche, H. Etzrodt, M. Marsch
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, D-3550 Marburg (Germany)
Priv.-Doz. Dr. W. Thiel
Fachbereich Physikalische Chemie der Universitat Marburg (Germany)
[**I This work was supported by the Fonds der Chemischen lndustrie.
Angew. Chem. Int. Ed. Engl. 21 (1982) No. 2
lne
I
w
C6H5
trans - 1
5-2K
c
out the presence of the valence isomer of 5-2K corresponding to 3-M and 4, the 1,4-dipotassio-l,2,3,4-tetraphenylbutadiene 6-2K, as an alternative. Nevertheless, according to M N D O calculations 6 2 e is only 11.2 kcal/mol
less stable than 5”.
The N M R spectra of the dianion confirm the presence
of 5-2K: I3C-NMR: 6=108.8 (CI-“), 141.9 (C5), 122.9
(C“,”), 127.7 (C7.9), 112.8 (C’); ‘H-NMR: 6=6.93 (d,
H””), 6.61 (t, H’.9), 5.97 (t, H’).
Furthermore, it follows from the NMR spectra that the
phenyl groups take over a considerable part of the negative
charges. Thus, the charges pemp[l1,
which can be determined
from the I3C-NMR spectrum, and which correlate with the
calculated pMMNDO
charges, indicate that only about 36% of
the two negative charges are found on the four-membered
ring C-atoms. Also consistent with this conclusion is the
calculated M N D O n-bond order of 0.470 for the exocyclic
bonds (e.9. C’-C5), whereas a bond order of only 0.450 is
obtained for the bonds in the four-membered ring.
The exceptionally low acidity of 2-M, the calculated enthalpies of formation AHf, and the charge distribution obtained from the N M R data d o not characterize 5-2K as
‘‘aromatic”’’.
It can be concluded from these results
that the unsubstituted cyclobutadienediide dianion must be
still more energy-rich and more basic than 5-2K, because
stabilization by delocalization of charge(s) in the phenyl
groups is missing there.
Received: September 4, 1981 [Z 985b IE]
German version: Angew. Chem. 94 (1982) 141
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982. 355-360
[I] G. Boche, H. Etzrodt, M. Marsch, W. Thiel, Angew. Chem. 94 (1982)
141: Angew. Chem. Int. Ed. Engl. 21 (1982) 132.
[2] H. H. Freedman, G. A. Doorakian, V. R. Sandel, J. Am. Chem. Soc. 87
(1965) 3019.
[S] a) A. 1. Hart, D. H. O’Brien, C. R. Russell, J. Organomet. Chem. 72
(1974) C 19: b) J. Hartmann, M. Schlosser, Helu. Chim. Acta 59 (1976)
453.
[I21 b) B. A. Hess, L. J. Schaad, Pure Appl. Chem. 52 (1980) 1471.
Novel Chlorooxoaluminates**
By Uv TheWalt* and Friederike Stollmaier
The reductive Friedel-Crafts synthesis of arene-transition metal complexes generally leads to formation of saltlike compounds containing arene-metal cations and chlo[*] Prof. Dr. U. Tbewalt, F. Stollmaier
Sektion fur Rontgen- und Elektronenbeugung der Universitet
Oberer Eselsberg, D-7900 Ulm (Germany)
[**I This work was supported by the Fonds der Chemischen Industrie.
0 Verlag Chemie GmbH. 6940 Weinheim, 1982
0570-0833/82/0202-0133 $02.50/0
133
roaluminate anions[]]. By means of X-ray structure analyses we have now been able to characterize products containing chlorooxoaluminate ions. The complex compounds
[(C6H6)(C6(CH,)6)Cr]+[AI,CI,O]- ' 112 C.5H6[Za1
and
. 2 CHzC1z[4"1, both of
[(C6(CH3)6)~Nb~C14]2f[A~~c~~~oz]zwhich are extremely sensitive to hydrolysis, contain the
A
,
CH3CH3 CIi3
1
2
3
novel anions 1 and 2. in which the 0-atoms are surrounded by a n almost trigonal-planar arrangement of Alatoms. In l a distorted trigonal-bipyramidal coordination
is realized for one of the Al-atoms. The axial AI-CI distances (2.63 and 2.73
are markedly gJeater than the
equatorial AI-CI distances (2.07 and 2.07 A) The structure
of 2 is analogous to that of the X-ray crystallographically
characterized[61alumosiloxane 3.
A)
Received: June 19, 1981 [Z 991 IE]
German version: Angew. Chem. 94 (1982) 137
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982, 209-213
[ I ] E. 0. Fischer, H.-P. Fritz, Angew. Chem. 73 (1961) 353.
[2] a) The compound is formed in small amounts along with other products
in the reaction of CrCI2, AICI,, Al and (CH2)& in benzene in a bombtube at 120°C (13 h).
141 a ) The compound is formed, along with other compounds, when the
product prepared by melting together NbCIS, (CH3)&, AlC13 and Al is
dissolved in CHzCIz and the solution briefly exposed to air.
[6] M. Bonamico, G. Dessy, J. Chem. SOC.A 1967. 1786.
Rotation of Polymerized Vesicles in an Alternating
Electric Field **
By Hans-Henning Hub, Helmut Ringsdorf, and
Ulrich Zimmerrnann*
Suspended cells rotate at certain frequencies in alternating electric fields['"]. The frequency ranges in which suspended cells rotate are species-specific and/or membranespecific (e.g. 20-40 kHz for mesophyll protoplasts of Avena sativa, 100-200 kHz for erythrocytes, 140-180 kHz
for yeast cells, 30-40 kHz for permanent cell lines, and 1
MHz for plant protoplasts and erythrocytes treated with
pronase). The rotation (about 1 rotationls) is a function of
the square of the field intensity"]. Theoretically, it can be
attributed to an interaction between induced dipoles in
neighboring cells. Maximum coupling between the neighboring dipoles occurs when the cells are oriented at an angle of 45" to each other['b1.Rotation of a free cell is, therefore, not possible if the cell is far enough away from the
[*I Prof.
Dr. U. Zimmermann
Arbeitsgruppe Membranforschung am Institut fur Medizin
der Kernforschungsanlage
Postfach 19 13, D-5170 Julich (Germany)
Dr. H. H. Hub, Prof. Dr. H. Ringsdorf
Institut fur Organische Chemie der Universitat
J.-J.-Becher-Weg 18-20, D-6500 Mainz 1 (Germany)
I**] This work was supported by the Deutsche Forschungsgemeinschaft
(SFB 160) to U. 2. We wish to thank Dr. I. Briiufigam and Dr. G. Pilwat.
KFA Julich, for helpful discussions.
134
0 Verlag Chemie GmbH. 6940 Weinheim, 1982
electrodes and other cells (however, see"?). Dipole-dipole
interaction between two neighboring cells leads to a mean
torque different from zero.
Maximum torque occurs when W T = 1 (z is the relaxation
time of the dipole build-up and o is the angular frequency). According to theory[''], the number of rotating cells
should, therefore, progressively decrease towards higher
and lower frequencies.
On the other hand, our studies of erythrocytes, plant
protoplasts, and permanent cell lines have revealed that
cell rotation can be induced in the frequency range 70140 MHz. The discrepancy between theory and experiment
can be explained if it is assumed that various relaxation
mechanisms underlie the build-up of a dipole in cells. Dipoles may be, induced, inter alia, by the orientation of the
phospholipids and/or proteins in the membrane or by
charge separation at the membrane. The relaxation time, t,
can be calculated for the latter mechanism[31.
Systems such as polymeric diyne-lipid vesicles (from
lipid 1 or 2), which are homogeneous and have fixed components, should therefore exhibit only one frequency
range for maximum rotation, since dipoles can only be
built up by charge separation.
CH,(CHZ) I~-CEC-CEC-(CH,),-COO-(CH~)~\
CH,( C H2) I~-CEC-C~C-(
C H2)x-COO-(CH&'
C H.i(CH 2) I2-C=C-C=C-(
o ,CH,
N
'CH,
C H 2)S-CH 2 0 - P 0 ( 0 H)Z
Monomeric diyne-lipid vesicles[41prepared in distilled water at 70°C and polymerized afterwards, were exposed to
an alternating field of 100 kHz between two parallel cylindrical electrodes glued to a microscope slide. Because of
the inhomogeneity of the field the vesicles migrate towards
the region of higher field intensity (i. e. towards the electrodes) and form "pearl chains" as a result of the forces of attraction between the dipoles induced in the vesicles by the
field[". If several parallel pearl chains are formed, many
vesicles are oriented at an angle of 45" to each other. Rotation of the vesicles is observed in the frequency range 1-4
MHz. As predicted by theory, no rotation was observed
outside this frequency range up to 170 MHz or down to
10 kHz (minimum output voltage of the high frequency
generator 3-5 V, electrode distance 100 pm). No experiments could be carried out in the frequency range 40-70
MHz because of resonance in the experimental system.
According to theory[31,the frequency at which all vesicles rotate is displaced to higher values when the intraand/or extravesicular conductivity of the vesicles is increased. Polymeric vesicles prepared and incubated in a
lo-, M KCI solution exhibited the predicted shift towards
higher frequency (7-15 MHz). N o rotation was observed
in the remaining, experimentally accessible frequency
range. If the intravesicular KCI concentration was raised
~
no rotation was observed in the entire freto 1 0 - 2 KCI
quency range, The reason for this observation may be that
the membranes become permeable so that charge separation can no longer take place.
These results demonstrate that the rotation observed in
the range 20 kHz-3 MHz in different cell types is very
probably attributable to charge separation. Rotation of
cells in the 100 MHz range must thus be attributable to an
orientation of dipoles within the membrane or to the OCcurrence of rotating fields in this frequency range. If it
were possible to determine and assign the respective specific frequencies for the orientation of these components in
the high frequency range using artificial lipid vesicles of
various compositions and fluidities, the determination of
0570-0833/82/0202-0134 $ 0 2 . 5 0 / 0
Angew. Chem. Inr. Ed. Engl. 21 (1982) No. 2
BrO
1
2
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