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Stable 1 1 Adducts from Iodoacetylenes and Iodide Ions Ion Pair Strain as an Additional Driving Force.

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I H. N . Schiiter. H. Burzlaff. A. H. Grimmeiss, R. Weiss. A r m
Crjstullogr.
Scci. C 1992. 48, 912-913.
I A. H. Grimmeiss, Disserration, Universitit Erlangen-Niirnberg. 1991.
I H. N . Schiifer. Dissertation, Universitit Erlangen-Numberg, 1992.
I R. Weiss. K . Schloter. Tetrohedrori Lett. 1975, 3491-3494.
R. Weiss. A. H. Grimmeiss. Z. Nuturforsch. B 1989, 44, 1447-1450.
R. Weiss. A. H. Grirnmeiss, Z . Nutirr/orsch. B 1991, 46, 104-110.
R. W. Johnson. 7i.rruheclron Lerr. 1976, 589-592.
L. Eberson. .4<ia Ciiern. Scand. Ser. B 1984, 38, 439-459.
a ) Crystal structure analysis of 2 (C,,H,,CI,N,02); M = 410.76. orthorhombic. space group P b m . u = 11.544(4). h = 13.206(8), c = 13.784(3) 8,ix = fi =
7 = 90 . V = 2101(2) A’. Z = 4. pLalCs
= 1.298 Mgm-3, data collection on a
Nicolet R3mv four-circle diffractometer with monochromated Mo,, radiation.
(i
= 0.71073) in the range 4 < 20 < 57”; 3505 reflections measured of which
2525 independent: structure solution with direct methods (SHELXTL Plus
4.1 1 ); data refinement using full matrix against F 2 using the least squares
method (SHELXL 93, G. M. Sheldrick. Universitlt Gottingen. 1993). All
non-hydrogen iitoms were refined anisotropically; all hydrogen atoms were
localized using difference Fourier syntheses and independently refined isotropically; 191 refined parameters: R values for [ I > 2u(I)]: R1 = 0.0594:
uR2 = 0. I51 1. b) Further details of the crystal structure investigations may be
obtained from the Director ofthe Cambridge Crystallographic Data Centre, 12
Union Road. GB-Cambridge CB2 1EZ on quoting the full journal citation.
R. Schwesinger, R. Link, G. Thiele, H. Rotter, D. Honert. H.-H. Limbach, F.
Miinnle. Anpcw. Cham. 1991. 103, 1376-1378: Angew. Chem. fnr. Ed. Eng/.
1991. 30. 1372.
J Bernsrein. M. C. Etter, L. Leiserowitz in Structure Conelution, Vol. 2 (Eds.:
H. B. Burgi. .I. D. Dunitz), VCH, Weinheim. 1994, pp. 431 -500.
Crystal structure analysis of 7 (C,,H,,CIN,O,); M = 391.9, monoclinic. space
groupP2,:ri.o =7.1360(9),h=19.332(5),c=15.975(4)~,~= 94.45(2)”. V =
2197.2(X) A3, Z = 4. pLAlFd
= 1.185 Mgm-’, data collected with a Huber fourcirclc diffractometer with monochromated Mo,, radiation, (/. = 0.71073) in
the range 6 i20 < 50’ ; 461 1 reflections measured. of which 3889 independent (R,,,,= 0.0103); structure solution with direct methods (SHELXSB6, G.
M. Sheldrick. Universitlt Gottingen, 1986); data refinement using full matrix
against F 2 using the least squares method (SHELXS76, G. M. Sheldrick, Cambridge. 1976).All non-hydrogen atoms were refined anisotropically; H 11 and
H 12 werc localized with difference Fourier syntheses and independently refined isotropically: all other hydrogen atoms were refined on geometrically
calculated positions with common U values using a riding model. 259 refined
parameters: R values for [ F z 3 u ( F ) ] :R = 0.0571; M’R= 0.0237 [14b].
We recently succeeded in determining the X-ray structure of the TDACliphenol
1: 1 adduct. In the previously unpublished structure, the O . . . C I distance IS
2.936 .&and thus considerably shorter than both the distances in the TDACli
hisphenol adduct. Only one example for a 1 : 1 H-bonding system is known in
the literature between p-nitrophenol and the electron-rich methyltri(p-nitrophenoxyjphosphonium chloride [19]. The fact that, in spite of the significantly
higher acidity of the phenol component (SpK, = 2 . 5 ) , an 0 - C I distance of
3.015 A is observed. about 0.08 8, longer than observed in the TDACliphenol
1.1 adduct, underlines the greater readiness of the chloride ion in TDACI to
coordiniite.
D. J. Schomburg. J Ant, Ciirm. Sor. 1980, 102. 1055-1058.
Of special interest is the structure of TDACl itself. Typically enough, the halides
cannot he obtained in solvent-free form. We interpret this as being an indirect
indication of thc unfavorable coordination relationships in an ionic lattice with
electronically similar components, but of opposite charge.
R . Wciss. T Brenner, unpublished results.
R. Wciss, M. Rechinger, F. Hampel. A. Wolski. Angew. Chen7. 1995. 107.483;
A ~ I ~ L JCI lVw. n I n i . Ed. E r t ~ l 1995.
.
34. 441.
Stable 1 :1 Adducts from Iodoacetylenes
and Iodide Ions: Ion Pair Strain
as an Additional Driving Force?**
Robert Weiss,* Michael Rechinger, Frank Hampel,
and Alexander Wolski
Dedicated to Professor Paul von Rag& Schleyer
on the occasion of his 65th birthday
The chloride ions of the salt 1a undergo coordination with
unprecedented readiness even with weakly acidic compounds to
form novel adducts with hydrogen bonds.[la1 In the case of this
salt, there were strong indications that a new type of strain in the
corresponding ion pair 1a is responsible for
the unusual reactivity of the chloride ion.
In order to check whether this activation
is also effective in the case of the “soft”
MezN x- N M e 2
iodide ions, we treated the salt 1 b with orla: X = C I
ganic iodine compounds as soft o* acceptors. This resulted in the formation of
lbX=I
many novel hypervalent adducts.[lbI
We report here on the reactions of 1b with 2-iodo-I-phenylacetylene (2) as a monofunctional o* acceptor, and with diiodoacetylene (3) as a bifunctional o* acceptor, in which stable
n + CT*adducts between iodide ions and C,,-bonded iodine centers were obtained for the first time.‘’] The two 1 : 1 complexes 4
and 5 were prepared by simply adding tns(dimethy1amino)cyclo-
X’
NMe,
R-C=C-I
+
,,&NMe,
1-
Me,N
2 (R=Ph)
3 (R=I)
lb
NMe,
CH,CI,
w R-C-C-1-I
a
ca 25 C
4 (R=Ph)
S(R=I)
propenylium iodide (TDAI) (1 b) to the acetylene component in
CH,CI,. Compound 4 was precipitated from the reaction mixture by addition of Et,O. Recrystallization from CH,CI2/Et,O
delivered 4 in the form of colorless needles which were suitable
for an X-ray crystal structure
The 1-1 distance of 3.44 8, in the anion of 4 is very long in
comparison to that in molecular iodine (2.66
but considerably shorter than the 1-1 bond length of 4.35 8, which would be
expected o n consideration of the sum of the van der Waals radii.[’]
Compared to the 1-1 distances of the adducts formed from iodide
and neutral compounds with C,,,-bonded iodine centers (3.57 3.69
the 1-1 bond in the anion of 4 is very short. It lies
in the range of those 1-1 distances that we found in iodocarbenium iodides with C,,,-bonded iodine atoms (3.37 A).[’] The
C-I bond of 2.02 A is longer than that of a noncoordinated
iodoa~etylene.[~I
One of the remarkable features of 4 is its extremely unusual
highly symmetrical ionic lattice (space group Pbam), which is
made up of an alternating series of purely anionic and purely
[*I
Prof. Dr. R. Weiss, DipLChem. M. Rechinger, Dr. F. Hampel, Dr. A . Wolski
Institut fur Organische Chemie der Universitiit Erlangen-Niirnberg
Henkestrasse 42, D-91054 Erlangen (Germany)
Telefax: Int. code (9131)85-9132
This work was supported by the Fonds der Chemischen Industrie.
+
[**I
A n p w . Clicm. In,. Ed. Engl. 1995, 34. N o . 4
(3 V C H
Verlug.sge,sellschufr mbH, 0.69451 Weinhcim, 1995
0570-0S33i95/0404-0441$ 10.00 + .2.(.0
44 1
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cationic layers. Both dipole-dipole interactions and hydrogen
bonds are determining factors for the buildup of the anionic
lattice as a whole (Fig. 1 a). In each case, two anions connect to
form a head-to-tail adduct by dipole-dipole interactions. These
pairs of anions are connected to one another through weak hydrogen bonds between the terminal iodine atom and an ortho-hydrogen atom of a neighboring phenyl ring (colored black in Fig.
1 a) to give an absolutely planar layer with dense packing.["]
Fig. 2. Crystal structure of 5. Selected distances [A] and angle [
3 398, 1-1-1 69.9; the CH,CI, molecules are not shown.
Fig. 1. a) Crystal structure of the anion in 4. Selected distances [A]: C-I 2.02.1-1
3.44. b) Crystal structure of the cation in 4. c) Crystal structure of 4.
Layers of likewise planar TDA cations lie between the individual anion layers, and are hexagonal closest packed in the lattice
(Fig. 1 b). Thus, each cyclopropenylium ion is placed directly
above or below the phenyl ring of an anion. As in graphite, the
distance between the two layers is 3.35 A.1' '1 The cohesion of the
layers in the lattice is brought about primarily by electrostatic
interactions which are superimposed by van der Waals forces. The
latter are probably responsible for the stacking of the aromatic
components. The crystal structure of 4 is shown in Figure 1 c.
In contrast to 2, diiodoacetylene 3 can function as a bifunctional o* acceptor. With the intention of preparing the corresponding
2: 1 adduct of TDAI and diiodoacetylene, 1band 3 were allowed
to react (mole ratio 2: 1) in CH,CI, . A colorless precipitate was
formed immediately; however, the analysis indicated only a 1 :1
adduct of the two components. On cooling the filtrate to - 18 "C,
5 precipitated with one equivalent of CH,Cl, in the form of
colorless needles which were suitable for an X-ray structure
analysis.["] The molecular structure of 5 is shown in Figure 2.
The system TDAI/diiodoacetylene 5 forms a novel hypervalent one-dimensional polymer. The bifunctional o*-acceptor
centers of diiodoacetylene are each connected by an iodide ion
442
0 VCH
V'rlagsgesellschuffl mbH. 0.69451 Weinheim. 1995
1: C-1
2 053, 1-1
which functions as a bifunctional donor with orthogonal lone
pairs.[' 31 The resulting polymeric zigzag chains lie exactly in a
plane. Quite remarkable in this is the unusually small bond
angle of 70" which occurs on the dicoordinate I- ion; this value
was also determined in n --* rs* adducts formed from iodide and
i ~ d o f o r m ; [71~ .as yet this cannot be explained satisfactorily.
Both the 1-1 bond length of 3.398 8, and the C-I bond length
of 2.053 8, lie in the same range as those in the monomeric
structure 4. The TDA cations in 5 are arranged above the partially anionic iodine center at a distance of 3.36 A and form a
stacking structure running perpendicular to the anionic polymer. All cations within a stack are arranged in an eclipsed fashion. A structure that forms part of a "corrugated structure" thus
ensues, in which neighboring zigzag chains interlock in the manner shown in Figure 2.
Whereas 4 forms a two-dimensional layer lattice, 5 has only
a one-dimensional band structure. Only those TDA cations,
which belong to one "anion wire", are found in the same plane.
The cations of two neighboring polymeric wires are shifted by
1/2 in the z direction. In this way a molecular lattice results
which is also found in other TDA salts.['51
The question posed at the beginning concerning an increased
readiness for coordination of the iodide ion in salts 1b, based on
the postulated ion strain, can only be partially answered at the
moment. Whereas 2 only forms a hypervalent adduct with 1b,
but not with other iodide donors,[1613 can also be successfully
treated with alternative sources of iodide." 71 A conceivable reason for this behavior is the known higher rs* acidity of C,I,
compared with that of 2-iodo-1-phenylacetylene (2),[''I which
could effect a leveling influence with respect to the iodide coordination.
Experimental Procedure
4: 2 (0.1 5 mL, 250 mg. 1.1 mmol) was dissolved in CH,CI, (20 mL) and a solution
of 1b (315 mg, 1.1 mmol) in CH,CI, ( 5 mL) was added dropwise at room tempera-
ture. After the mixture had been stirred for 18 h, the adduct was precipitated by
addition of Et,O. then filtered off and washed twice with Et,O (10 mL). and dried
under vacuum for 8 h. Yield: 520 mg (92%). Single crystals of 4 were obtained by
recrystallization from CH,CI,/Et,O. C, H, N elemental analysis correct; 'H-NMR
(400 MHz; CDCI,. 25 "C. TMS): 5 = 3.21 (s. 18H, N(CH,),), 7.32 (m. 3H, CH).
7.41 (m. 2 H , CH); I3C-NMR (100 MHz; CDCI,. 2 5 T , TMS): 6 =11.9 (CI), 42.9
(N(CH,),. 92.9 (CCI), 117.9, 123.4, 128.1, 128.4. 132.0; IR (KBr): C[cm-'] = 3050
(w). 1545 (ss), 1205 (m), 1070 (m), 1050 (m), 1010 ( s ) , 790 (w), 770 (m), 760 (m),
750 (m), 700 (w). 680 (m): Raman: G[cm-'] = 3037(w), 2919 (m), 2804 (w). 2147
( s ) . 2071 (w). 1590 (s), 1210 (s). 1179 (w). 995 (m), 802 (w). 563 (m), 526 (w), 331
(w),214(s), 132(s);MS(70eV):rn/z(%):228(100)[C8H,I+].127(8)[It], 101 (30)
[C,H:I.
0570-0833195jO404-0442 $ 10.00+ .25/0
Angew. Chern. Int. Ed. Engl. 1995, 34, No. 4
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5: 3 ( I 2.1 g. 4.44 iiiinol) was dissolved in CH,CI, (20 m L ) . A solution of I b (I.31 g.
4.44 mmol) in CH,CI, (10 mL) was added dropwise at room temperature. After the
addition w:is complete. the product precipitated in the form of white needles. The
reaction mixture
stirred for a further 5 h. the product filtered off and washed
twice w i t h C l i , C I , ( I ~ l m L ) . a n d d r i e dundervacuumfor8 h.Yield:2.32 g(91.4%).
Single crymils were obtained by allowing the filtrate to stand at - 20 C for 24 11. C.
H. N elcinental analysis correct, IR (Nujol): i[ciii-l] =I550 (ss). 1220 (ss). I050
( i n ) , 102(1(s).785(5). 720(w).630(s): Raman: P[cm-’] = 2078(m). 1987(w). 1406
( w l . 1 7 X 7 ( ~ ) .122X(w). 1 0 2 X ( w ) . 7 8 7 ( w ) . 6 3 4 ( m ) . 6 0 ~ ( ~ ~ ) . 5 4 3 ( w ] . 3 1 6 ( m
168
).
( s s ) ; M S ( 7 0 eV1. 111 3 (”/ol: 278 (100) [CLll].254 ( 8 5 ) [I:].
127 ( 6 5 ) [ I + ] .
Received: July 20. 1994 [Z7148IE]
German version: Angew. C h ~ i n1995.
.
107, 483
Keywords: adducts cyclopropenylium compounds . halogen
compounds . hypervalent compounds . solid-state structures
[ I ] a ) R. Weias. 7 Brenner. E Hampel. A. Wolski. A i i g w . Chem. 1995. 107, 481 :
Atigr,ii.. Chcni. 1 ~ rEd.
. Eng/. 1995. 34, 439: h) M . Rechinger, Dissertation.
Universitit Erlangen-Nurnberg. 1995.
[2] Strong n a* contacts between iodide and C,,-bonded iodine were postulated
hq u b iii explaining the reaction behavior and the extraordinary insolubility of
~;i~cki-C,I,
(31.
[3] i i ) R. We]%\.H. Wolf. U. Schubert. T. Clark. J. , 4 1 1 1 . Choii. Soc. 1981. 103,
6142 6147: b) A. E. Reed. F. Weinhold. R. Weiss, J. Macheleid, J. P/iys. Chem.
1985. 89, 2688-26’94: cl R. Weiss. G.-E. Miess. A. Haller, W. Reinhardt.
.4iIgrlr. C / i w i . 1986. 98. 102- 103; A i i g ~ i C/ILW?.
~.
1111.Ed. Eiigl. 1986. 35, 103 I04.
[4] ii) Crystal rtructure analysis of 4 (Cl-H2312N3):A4 = 523.18. orthorhomhic.
space group P/xrin, N = 16.925(1). h = 18.254(1), c = 6.6976(8)
a = /I =
> = 90 . L ’ = 2069.2(3) A’. Z = 4, prrird= 1.679 Mgrn-’, 9084 reflections collected (3.0 < 20 < 26.0’). 2222 independent and 1491 observed reflections
[ F A > 20(/-“)]. 13Y refined parameters. R = 0.0288, IVR= 0.0719); all data
\+ere collccted with :i Hubcr four-circle diffractometer at 291 K with Mo,,
r;idi;ition (i= 0.70993 .A). The structure was solved by direct methods
(SHELXS8hfSHELXL93).All non-hydrogen atoms were anisotropically relined. a11 hydrogen atoms isotropically. h) Further details of the crystal structure investigations may be obtained from the Fachinformationszentrum Karlsruhe. D-76344 Eggenstein-LeopoldshaFen (Germany) o n quoting the depository nuinbei CSD-58743.
[ 5 ] N N. Grcenu’ood. A. Earnshaw. Chiwi;.strr (11/hc Elr~ii?m~.s.
1. ed.. Pergamon.
Oxford, 1984. p. 934
[h] R Weiss. M . Rechinger, unpublished results.
[7] H:G. Lt7hr. .4. Engel. H.-P. Jose]. F. Vogtle. W. Schuh. H. Puff. J. Org. Cliern.
1984. 4Y. 1621 1627.
[8] R Weis\. M . Rechiiiger. F. Hampel, A n g ~ w .Chcni. 1994, 1116. 901 -903:
.4ii,wi1..(‘Iwiii. h / .Ed. Engl. 1994. 33. 893 895.
[Y] J. Sheridan. W. Gordy. P/IK\. Rev. 1952. 20. 735.
A. I . Kitaigorodski. Moli~kiilkristuNe,Akademie-Verlag. Berlin, 1979.
A. F. Hollemann. E. Wieberg. Lehrhuch rkr Anorguiiischm Chrinir. 91. 100. ed.. de Gruyter, Berlin, 1985, p. 702.
C rystal \1i-uctureanalysisofS (C,2H,8CIJ3N3); M = 655.9. monoclinic. space
eroup (‘2.c.. LI =7.231(2). h = 22.916(8). c =12.497(4) A, 1 = Y O ,
=
89.98(3). ;= YO , V = 2070.8(11) A’. Z = 4. pEAiEd
= 2.104 Mgm-’. 4767 reflection\ collected (3.0 < 2f) < 55.0 ) > 2442 independent and 1970 observed
reflection\ [ F > 4.0r(F)]. ’92 refined parameters, R = 0.0427. 1i.R = 0.0575); all
d a t ~werc collected with a Siemens R3miV diffractometer at 200 K with Mo,,
The structure was solved by direct methods
radialion (j. = 0.71073
(SHELXTL-PLUS (VMS)) All non-hydrogen atoms were refined anisotropically. all hydrogen atoms isotropically in fixed ideal positions (riding model)
[4bl .
In \tructuriil analogy to the bonding situation in the 1; ion 1141.
R. .I. Hach. R . E. Rundle. J. An?. Client. S O L .1951. 73, 4321 -4324.
R. Weias. M . Rechinger. F. Hampel. 2. Kri,Tru/kJgr..in press.
Tetrahutylammonium iodide and hexamethylguanidinium iodide were used as
;iddition;il hources of iodide.
1 : I iidduct\ of a s yet undetermined structure were thus formed.
C. Laurence. M. Queignec-Cahanetos, T. Dzienibowbka. R. Queignec. B. Wojtkowiak. .I..Am. C / i m . Soc. 1981. 103. 2567-2573.
-
Tris(dimethy1amino)sulfoniumcyclopen tadienide
[TAS]+[C,H,]- and Tris(dimethy1amino)sulfoniumpyrrolide [TAS] [C4H4N]- : Two
Isostructural Salts with “Naked” Anions A and the “Inverse” Sandwich-Cations
[{(Me,N),S},A]+ (A = C,H,, C4H4N-)**
+
Jens Wessel, Ulrich Behrens, Enno Lork,
and Riidiger Mews*
The cleavage of Si-C bonds by Bu,NF or similar organic
fluorides serves to remove Me,Si protective groups with subsequent formation of C-H bonds.”] Intermediates in these reactions are highly reactive carbanions, which, under the reaction
conditions chosen, can abstract protons from neighboring molecules. Particularly suitable for the cleavage of Si-element bonds
is “TAS-fluoride” (tris(dimethy1amino)sulfonium difluorotrimethylsilicate) [(Me,N),S]+[Me,SiF,]- (l),[‘, which is readily
available in HF-free form; the chemical behavior of the fluorosilicate ion corresponds to that of a “naked” fluoride ion.141
From the reaction of TAS-fluoride (1) with C,H,SiMe, (2) in
CH,CN at -40 “C, the TAS salt 3 can be isolated in high yield
as a reddish solid [Eq. (a)].
A,
A).
u
SiMe3
3
2
The salt 3 is stable as a solid at room temperature. However,
in CH,CN and CH,CI,, which are suitable solvents at low temperatures, 3 decomposes between -40 “C and - 10 “C to give
C,H, among the products.
The aim of our investigations was the generation and the
detection of “naked” Cp- ions in the presence of base-free
cations (that is, cations not complexed by auxiliary bases such as
N,N,N’,N’-tetramethylethylenediamine
(TMEDA)); only two
examples of “naked” Cp- ions have been characterized by structural investigations in transition metal chemistry: [[Re(NO)(CH,)(PMe,),]+[C,H,]-[61
and [Rh2(dmpe),(p-dmpe)12+[C,H;12 (dmpe = 1,2-bis(dimethylphosphano)ethane).[’I In all
of the other known structures of cyclopentadienide salts there
are interactions between the anions and the cations.[’] This leads
to the formation of polymeric structures (“supersandwich”
compoundsrg1)in alkali metal derivatives; these interactions are
not terminated by the complexation of the cations by auxiliary
bases.[’01
In TAS salts there are practically no cation-anion interactions in the solid state.rt11Therefore, the TAS’ ion seemed
particularly suitable for the generation of “naked” Cp- ions.
The crystal structure of 3 (Fig. 1 ) and the view of the crystal
lattice (Fig. 2) show that the TAS cyclopentadienide can best be
[*] Prof. Dr. R. Mews. J. Wessel. Prof. Dr. U. Behrens. E. Lork
lnstitut fur Anorganische und Physikalische Chemle der Universitit Bremen
Leobener Strasse NW2. Postfach 330440. D-28334 Bremen (Germany)
Telefax: Int. code + (421)218-4267
[**I
This work was supported by the Fonds der Chemischrn Industrie. We would
like to thank one of the referees for the discerning examination of the
manuscript.
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adduct, iodoacetylenes, ion, strait, additional, pairs, force, ions, iodide, stable, driving
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