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Organometallic Host-Guest Systems Representing Novel Charge-Transfer УIon PairsФ with Three-Dimensional Electron-Donor Networks.

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[l] a) A. McKillop, E. C. Taylor, Adv. Organomel. Chem. I 1 (1973) 147; b) A.
McKillop, E. C. Taylor in F. G. A. Stone, E. Abel (Eds.): Comprehensive
Organometallic Chemistry, Vol. 7, Pergamon, Oxford 1982, p. 499.
[2] B. Gyori, A. Sanchez, J. Glaser, J: Organomet. Chem. 361 (1989) 1
131 J. Vicente, J. A. Abad, J. F. GutiCrrez-Jugo, P. G. Jones, J: Chem. Sot.
Dalton Trans. 1989, 2241.
[4] J. Vicente, M. D. Bermudez, M. T. Chicote, M. J. Sanchez-Santano, J.
Chem. SOC.Chem. Commun. 1989, 141.
(51 The only other diacetonyl derivative of which we are aware is
[Hg{CH,C(O)Me},], obtained by the reaction of [(Me,Si),N],Hg with
acetone[6]. The mercuriation of acetone in aqueous solutions leads to
mono- and polymercuriation of the acetone molecule[7].
I. B. Fedot'eva, 0. A. Kruglaya, B. V. Fedot'ev, N. S. Vyazankin, Zh.
Obskch. Khim. 48 (1978) 2387; Chem. Abstr. 90 (1979) 72293d.
F. A. Johnson, W. D. Perry, Organomerallics 8 (1989) 2646.
~ ' . NMR (200MH2,
M p. 165°C (dec.); A , = 1 0 3 ~ ~ ' c m 2 m o l 'H
[DJDMSO, TMS): 6 = 2.12 (s, 6 H ; Me), 2.58 (d, br, 2J(T1; H) =756 Hz,
4H;CH,). IR(Nujol):C[cm-'1 = l670,1650(C=O); 128O[SO,(E)], 1030
[SO,(A,)] 1225 or 1240 [CFJA,)], 1170 or 1180 [CF,(E)], all very strong.
M.p. 162"C(dec.); A =98R-'cm2mol-'. 'H NMR (200MHz, CDCI,,
TMS): 6 = 1.98 (s, 6 H ; Me), 2.99 (d, br, 'J(T1; H) = 692Hz, 4 H ; CH,).
IR (NuJo~):C[cm-'] = 1675, 1655 (C=O), 1285 [SO,(E)], 1025 [SO,(A,)]
1225(br) [CF,(A,)], 1155 or 1165 [CF,(E)], all very strong. Single crystals
of 2 were obtained by slow diffusion of diethyl ether into a solution of 2
in acetone.
G. A. Lawrance, Chem. Rev. 86 (1986) 17.
Crystal data for 2 at - 95 "C: C,,H,,N,O,F,STI (monomer), M = 623.8.
Triclinic, space group Pi,a = 848.2(3), b = 1008.4(4), c = 1288.5(5)pm,
c( = 102.73(3),
= 94.45(3), y = 106.63(3)', V = 1.0183 nm', 2 = 1 di= 2.034Mgrn-'. The final R value was 0.031 for 3167 reflecmer, eeslCd
tions > 4 4 0 . Further details of thecrystal structure investigation may be
obtained from the Fachinformationszentrum Karlsruhe, Gesellschaft fur
wissenschaftlich-technischeInformation mbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-54696, the
names of the authors, and the journal citation.
D. Seebach, Angew. Chem. 100 (1988) 1685; Angew Chem. In[. Ed. Engl.
27 (1988) 1624.
ties and thus a tendency to form charge-transfer (CT) adducts with numerous anionic[41and unchargedrs1 electron
donors.f3b1
Compounds 1 (G'@ = MV2@)and 2 (Gz@= BV2@)are
accessible in high yields via ion
according to
Equation (a). The "alloyed" host-guest systems 3 may be
a, M = Fe;
b, M
= Ru; c, M = 0 s
prepared correspondingly from the well-characterized precursors [(Me,Sn),Fe, -,Ru,(CN),],.
[(MV2@),,,(Me3Sn)3Fel -xRux(CN)6]m 3a, x
= 0.50;
3b, x
=
0.25
Suspension of 1 and 2 in an aqueous Na,S,O, solution
affords within a few minutes the likewise insoluble, pure
type-A systems 4 and 5, respectively, containing G'@guest
ions [Eq. (b)] .[6-81 Alternatively, 4 and 5 may be prepared by
a
Organometallic Host-Guest Systems Representing
Novel Charge-Transfer "Ion Pairs" with
Three-Dimensional Electron-Donor Networks **
By Stefan Eller, Martin Adam, and R. Dieter Fischer*
Dedicated to Professor Helmut Behrens
on the occasion of his 75th birthday
Recently, we described several examples of compounds of
type A, a widely variable new class of three-dimensional
(3D) host-guest systems involving guest cations G@like
+ [M(CN),]4e + 3 Sn'@ + organic products
(b)
"ion exchange"[61 starting from [(G@)(Me,Sn),M(CN),],
(G = NH,, Et,N, Me,Sn,"] and even 1/2 MV) and M V @or
BV.@ radical ions generated in situ. The NIR/VIS absorption spectra of 4 and 5 strongly resemble those of
(MV'@)(PF,) and (BV'@)(PF,), respectively (Table 1). The
ESR spectrum of polycrystalline 4bfg1reflects the involvement of only one type of radical ion. Exposure of pure
4 a and 4b to air results in less abrupt changes"'] than
for the apparently more sensitive, blue host-guest system
"(zeolite Y/MV'@}".f"l
A single-crystal X-ray study of 1b,'I2] the first well-crystallizing type-A specie^,"^. indicates that all MV'@ guest
ions are encapsulated in equally shaped cavities of "finite
dimensions" spanned by a 3D network of nonlinear
\/
\/
I\
I
f Ru - C = N - Sn - N = C f, chains regularly interlinked
by the octahedrally coordinated Ru" ions (Fig. 1). The short-
[(G"@)l,,(Me3Sn'v),M"(CN),la, M = Fe, Ru (type A)
NRf (R = alkyl), [(C,H,),Co]@, and even Me,Sn@.[" Here,
we wish to present the first type-A['] systems with
G2@= methyl- and benzylviologen (MV2@and BV2@,respectively), as well as with their reduced forms G@= M V @
and BV'@.[31Rod-shaped MV"@, and even more BV"@
(n = 1,2), requires a maximum of space in just one direction.
Moreover, MV2@and BV2@display notable electron affni[*] Prof. Dr. R. D. Fischer, Dip].-Chem. S. Eller, DipL-Chem. M. Adam
Institut fur Anorganische und Angewandte Chemie der Universitat
Martin-Luther-King-Platz 6, D-2000 Hamburg 13 (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie. We thank S. Schaugsdar for her
I
V O , for
~
assistance, for example, in the growing of single crystals, Prof. .
measuring an ESR spectrum, and Prof. U . Behrens for critical discussion
of the X-ray analysis.
1126
6
VCH VerlagsgesellschafimbH. 0-6940 Weinheim. 1990
Fig. 1. Unit cell [12] of 1 b (ORTEP). Some atoms of the MV2" guest ion have
been marked by an asterisk; the CH, groups of all Sn atoms have been omitted.
0570-0833/90~1010-1126
$3.50+ .25/0
Angew. Chem. Int. Ed. Engl. 29 (1990) No. I0
est host.. .guest separations may be deduced from the
smallest interatomic distances found, that is, 2.5 i 0.2 8, for
C(CN)...C(MV) and N(CN)..-C(MV) (Sn...C(MV) and
Ru...C(MV) > 3.5 A). In view of the different spatial demands of MV"@and BV"@and the variable host/guest ratio
(2 for 1 and 2, but 1 for 4 and 5), the architecture of the
polymeric host network o f 1,2,4, and 5 is expected to undergo characteristic variations.
Whereas the host-guest system "{zeolite Y/MV2Q)" has
been reported 15] to incorporate spontaneously various TLelectron-rich arenes D to form "{zeolite Y/(MV2@-D)}"
with colored CT complexes MV2@. D as guests, 1 and 2 do
not react in a corresponding fashion. The pronounced tendency of dissolved MV2@and [Fe(CN)6]40 ions, for example, to associate to give comparatively stable CT "ion
pairs"[41 suggests that the strikingly colored solids 1-3
(Table 1) are indeed genuine CT complexes.
Table 1. Properties of the solids 1-5 and of some dissolved samples of spectroscopic
relevance.
Compd
G""
M
la
lb
le
Za
2b
2c
3a
3b
4a
4b
5a
5b
MV2"
MV2"
MV25
BV'"
BV'"
BV2@
MV2"
MV'"
MV"
MV5
BVe
BV"
Fe
Ru
Color
CT maximum System for
la. bl
comparison
C[cm-']
blue
15 870
brick-red
21740
0s
violet
20 000
Fe
limegreen
17860
Ru
red violet
22220
0s
bright violet 21050
Fe/Ru violet
20410
Fe/Ru violet
20410
Fe
dark blue
25000 and
Ru
dark blue (16000
Fe
dark violet 26670 and
Ru
dark violet {I7860
G2"/
[M(CN),]4e/
H,O [c]
[dl
G'" (PF,)
INCCH,
CT maximum
[a]
C[cm-']
18 870 141
24 040 [4]
22 730
18 180
22 73O[e]
22 220
23 530
25 320 and
16 540
25420 and
I16260
{
[a] 1-3,inrermolecularelectron transfer; 4-5, inlrumolecular excitations of G " (principal bands). [b] Solid samples (KBr pellets). [c] Solution of (MV)CI, . H,O or (BV)Br,
and K,[M(CN),] ( l / l ) in H,O. [d] Solution of (MV)CI, . H,O, K,[Fe(CN),], and
K,[Ru(CN),] ( l / l / l ) in H,O. [el Salt 6b dissolved in H,O.
Actually, the NIRjVIS absorption spectra of 1 a - l c
(Fig. 2), as well as those of 2a-2c (Table l), display one
distinct potential CT band which is absent in the spectra of
their components. The Imax(CT)values of 1 and 2 may reasonably be correlated with the oxidation/reduction poten-
I -
LOO
600
hlnrnl
-
800
Fig. 2. Absorption spectra of la-lc and of 3a withtn the range of their CT
bands (samples, KBr pellets; Cary 17 spectrophotometer). E = extinction.
Angew. Chrm. Inl. Ed. Engl. 29 (1990) No. 10
tials of the couples [M"(CN)6]40/[M"'(CN)6]3@
and
G'@/G2@,['
b1 respectively. However, the bathochromic shift
of )-max(CT)of 1 and 2 (compared with /Z,,,(CT) of corresponding ion pairs in aqueous solution141)is surprising. It is
well documented['61 that, for example, the Lewis acid/base
neutralization shown in Equation (c) causes a notable de[Mii(CN),]4e
+ 6Lq
4
[Mii(CNL),]6q "(0 2 q 2 1)
(C)
crease in the electron-donor strength of the central d6 metal
ion. The influence of the Lewis acid Lq present in 1 and 2
(formally, L = l/2 Me,%@ with q = t / 2 ) should thus favor
a hypsochromic shift of AmaX(CT).
Further insight has so far
been hampered by the poorly structured solid-state absorption spectra["] of the easily accessible new salts (BV2@),[M"(CN),] . 3 H,O (6a-c), and the appearance of no more
than one broad CT absorption band also in the spectra of the
"alloyed" systems 3 (Table 1, Fig. 2).
Interestingly, the transition from the "CT sandwich" "bis(p-phenylene)-[34]crown-l O/MV2@' G { DAB/MVZ@/DAB}
(DAB = p-dialkoxybenzene) ['*I to the "inverted" (with respect to the donor and acceptor components) CT sandwich
{M~2@/DAB/MV2Qj(i.e.,
"cyclobis(methylvio1ogen-p-phenylene)/DAB" with DAB = p-dimetho~ybenzene['~])
is also
accompanied by a strong bathochromic shift of the main CT
band (436 vs. 478 nm[201).Possibly, collective phenomena
may operate not only in the latter cyclodimer[*'] but likewise
in the 3D polymers 1-3, strengthening both the acceptor
(coupled pair of MV2@ ions) and donor (coupled
[M"(CN),I4@ units) capacity. One illustrative example of an
ensemble of six arene units that can be collectively oxidized
in spite of the "isolation" of each individual n system
by CH, and (CH,), bridges is "spheric cryptophane".r22]
The spontaneously occurring ion exchangel6] [Eq. (d), see
l(so1id)
+ MV.@%4(solid) + 0.5 MV2@
(4
above16. z31] suggests some extra stabilization of the MV'@
ions encapsulated in 4.[241This feature is also likely to contribute to the bathochromic shift of the CT excitation (e).
x
< 0.5.
Experimental Procedure
1-3 (typical procedure): 0.3 mmol of [(Me,Sn),M(CN),lm (cf. [l]) was suspended in a solution of 0.3 mmol of (MV)CI,. H,O (Fluka) or (BV)Br,[7] in
40 mL of H,O. After stirring (room temperature, 12 h), filtration, washing with
H 2 0 , and drying under high vacuum, analytically pure products were obtained
(correct elemental analyses for C, H, N, Sn, and Fe in all cases). Yields between
82 (la) and 90% (Zb, 2 c ) ; decomposition temperatures between 200 (la)and
245 "C (2b).
[(Me,Sn),Fe, 5Ru,,(CN),]m (3a): Addition of a solution of Me,SnCI
(0.85 g, 4.26 mmol) in 10 mL of H,O to a solution of K,[Fe(CN),J (0.19 g,
0.53 mmol) and K,[Ru(CN),] (0.22 g, 0.53 mmol) in 15 mL of H,O; after stirring ( 5 h), filtration, washing with H,O, and drying (high vacuum, room temperature), 0.90 g (0.93 mmol) of analytically pure product was obtained (correct elemental analyses for C, H, N, Sn, and Fe; yield 87%; decomposition
temperature, 230 "C).
4 and 5 (typical procedure): Suspension of 0.3 mmol of 1 or 2 in a solution
of ca. 3.0 mmol of Na,Sz04 (Merck-Schuchardt) in 30 mL of 0,-free H,O
under an atmosphere of N, resulted in a color change to dark blue and dark
violet, respectively, within a few minutes. Analytically pure products were isolated in practically quantitative yields (when referred to MV'" and BV'", respectively) after prolonged stirring (3 h, room temperature), filtration, washing
with a small amount of H,O, and drying (high vacuum, 8 h); correct elemental
analyses for C, H, N, Sn and Fe. The filtrate, which still contained S,Oie
anions, was free of any MV'" or BV'" ions, but not of the anions [Fe(CN)6]4e
or [RU(CN),]"~
0 VCH Verlagsgesellschafi mbH, 0-6940
Weinheim, 1990
0570-0~33~90/1010-1127$3.50+.25/0
1127
(BV2e)2[R~(CN)6].
3H,O, 6b: A solution of (BV)Br2 (0.24 g, 0.48 mmol)
[7] in 15 mL of H,O was added to a solution of K,[Ru(CN),] (O.lOg,
0.24 mmol) in 5 mL of H,O. The instantaneously resulting violet precipitate
was separated from the filtrate, washed with a small amount of H,O, and dried
(high vacuum, 8 h). Yield, 74%; correct elementa1analyses for C, H, N, and 0.
Received: May 25, 1990 [Z 3977 IE]
German version: Angew. Chem. 102 (1990) 1157
~~
[I] S. Eller, P. Brandt, A. K. Brimah, P. Schwarz, R. D. Fischer, Angew.
Chem 101 (1989) 1274; Angew. Chem. Int. Ed. Engl. 28 (1989) 1263.
[2] All host-guest compounds related to 1-3, but involving also covalent
host-guest linkages (including hydrogen bonding), are here referred to as
type-B systems; see [l] and M. Adam, A. K. Brimah, X.-F. Li, R. D.
Fischer, Inorg. Chem. 29 (1990) 1595, as well as the structure of
[(Me,Sn),Fe"(CN), . 4H2OIb (U. Behrens, A. K. Brimah, R. D. Fischer,
unpublished results).
[3] a) MV"' = l,l'-dimethyl-4,4'-bipyridinium; BVne = l,l'-dibenzyl-4,4'bipyridinium (n = 1,2); an alternative name for methylviologen is paraquat; b) For some other host-guest systems with MVZe, see, e.g., footnote
1 of 1191.
[4] See H. E. Toma, Cun. J Chern. 57 ( 1 979) 2079.
[5] Donor = mesitylene, durene, as well as some naphthalene and anthracene
derivatives; see K. B. Yoon, J. K. Kochi, J. Am. Chem. Sac. 1f0 (19118)
6586.
[6] Increasing experimental evidence suggests that these and some related
reactions intermediately involve partial cleavage of the initial polymer,
followed by spontaneous self-assembly of the new polymer: cf. S . Eller, P.
Schwarz, P. Brandt, R. D. Fischer, unpublished results; S. Eller, S . Dulsen,
R. D. Fischer, J. Organornet. Chem. 390 (1990) 309.
(71 Prepared according to W. Geuder, S. Hiinig, A. Suchy, Tetrahedron 42
(1986) 1665.
[S] The stability of all Me&'" building blocks remaining in the resulting 3D
coordination polymer is unexpected in view of the presence of strongly
reducing S,O:e and G' ions; however, all Me&'" units liberated according to Equation (b) undergo reductive decomposition.
[9] Appearance of only one symmetrical signal ( T = 22°C; g = 2.0416, line
width ca. 2.3 G).
[lo] When exposed to air, a KBr pellet of 4 b does not show any notable
changes in its absorption spectrum after at least 24 h, and the color of
finely powdered, pure 4 a turns green only after several days (the two
principal absorptions of the MVe ion merging below 550 nm to one very
broad signal).
[ l l ] K. B. Yoon, J. K. Kochi, J Am. Chem. SOC.1 1 1 (1989) 1128.
1121 X-ray structure analysis of 1b: SYNTEX P2, four-circle diffractometer
with graphite monochromator (Mo,, radiation. j. = 0.709261 A). Orthorhombic cell, space group Pmna with a = 11.248(1), b = 16.459(2).
c = 17.648(3)A, V = 3267 A3, Z = 4. Partial disorder involving one of the
CNSnNC fragments was accounted for to arrive at the solution of the
structure presented in Figure 1. Use of 3159 symmetry-independent reflections with F 2 40(F); after refinement of 181 parameters, convergence at
R = 0.068, R , = 0.076 with w = 1.9346 [02(F)
+ 0.0005 F 2 ] - ' .The final
structure of 1b will be published elsewhere in detail, taking into consideration an apparent superlattice (doubling of the number of parameters).
[13] For the structures of two type-B compounds, see [2].
[14] One remotely related type-A system is the recently described 3D polymer
[(NMe,)Cu', SZn", ,(p-CN),IS: see B. F. Hoskins, R. Robson, J. Am.
Chem. Sac. 112 (1990) 1546.
1151 a) I? (vs. SCE) = 0.19 (Fe), 0.70 (Ru), and 0.40 (0s) V ; cf. J. C. Curtis,
T. J. Meyer, Inorg. Chem. 21 (1982) 1562; b) I? = - 0.69 (MV) and - 0.58
(BV) V; cf. Z. Li, C. M. Wang. L. Persaud, T. E. Mallouk, J Phys. Chem.
92 (1988) 2592.
[16] See D. F. Shriver, Structure and Bonding 1 (1966) 32.
[17] As a rule, E.,,,(CT) of a solid sample turns out to exceed
(CT) of a
corresponding solution; cf. H. Kuroda, M. Kobayaschi, M. Kinoshita, S.
Takemoto, J. Chem. Phys. 36 (1962) 457.
[IS] B. L. Allwood, N. Spencer, H. Shariari-Zavareh, J. F. Stoddart, D. J.
Williams, J. Chem. Sac. Chem. Commun. 1987, 1064.
[I91 B Odell, M. V. Reddington, A . M . 2. Slawin, N. Spencer, J. F. Stoddart,
D. J. Williams, Angew. Chem. 100 (1988) 1605; Angew. Chem. I n t . Ed.
Engl. 27 (1988) 1547.
[20] Even concentrated solutions of (MV)CI, and p-dimethoxyhenzene in
NCCH, (2: 1) do not show any clear CT band.
[21] In the former cyclodimer, the two DAB units are linked via fairly long, and
thus optimally "isolating", (CH,). bridges.
[22] A. Renault, D. Talham, J. Canceill, P. Batail, A. Collet, J. Lajzerowicz,
Angew. Chem. 101 (1989) 1251; Anxew. Chem. I n / . Ed. Engl. 28 (1989)
1249.
[23] For M = Ru (1b + 4 b), the reaction is accompanied by the following
color changes: red + blue (suspended solid) and blue +colorless (aqueous
solution).
[24] The redox potential F of the pair MV"/MVZe is also known to vary with
the solvent: see C. L. Bird, A. T. Kuhn, Chem. Sac. Rev. 10 (1981) 49.
1128
8
VCH Verlagsgesellschaft mbH. 0-6940 Wernherm, 1990
Isomerization of Benzoylalkylidene Sulfur
Tetrafluorides C6H,-CO-CR = SF, to
Dihydrooxathietes**
By Thomas Henkel, Thomas Kriigerke, and Konrad Seppelt *
Of the six known alkylidene sulfur tetrafluorides
RR'C = SF,, only F-CO-CH = SF, bears a C-functional
group."] In the crystal at - 168"C, this compound has a
fully planar molecuIar framework with C-S and C-0 double
bonds arranged in a cis fashion."] Like most alkylidene sulfur tetrafluorides, it exhibits considerable stability. In attempts to prepare the benzoyl-substituted compounds
C,H,-CO-CR = SF, (l),however, they could only be detected as intermediates by "F NMR (R = H) or were not observed at all (R = Br), since they isomerize immediately to
the isolable oxathietes 2. Because the "F NMR spectra of
0
I
0
Br
A
C,Hs-;-CH,-SF,
C6H5 - i-CHBr - SF5
/
o\
//SF4
,c-c,
C6H5
-
0 -SF4
I
I
c =c,
R
C&5
1
2
R = H.Br
isomers 1 and 2 reveal an A,BC system in each case, signal
assignment requires plausible assumptions regarding the
chemical shifts and coupling constants. This is possible for
the alkylidene sulfur tetrafluorides, but reference spectra are
lacking for the new S-tetrafluorodihydrooxathietes. The Xray structure analysis (Fig. I) unambiguously established the
presence of the unsaturated four-membered ring.131
Fig. 1. Molecular structure of 2, R
=
H, at - 153 "C (XP plot).
Owing to the special geometry of alkylidene sulfur tetrafluorides such as 1, where the substituents at carbon lie in the
plane defined by the sulfur and the axial fluorines, an approach of the carbonyl oxygen to the sulfur requires that one
axial fluorine be pushed aside. The necessary twisting
around the C-S double bond can occur in three ways
(Scheme 1): rotation, pseud~rotational[~~
painvise interchange of axial and equatorial positions, or a combination of
[*] Prof. Dr. K. Seppelt, DipLChem. T. Henkel, Dr. T. Krugerke
Institut fur Anorganische und Analytische Chemie der Freien Universitat
Fabeckstrasse 34-36, D-1000 Berlin 33
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
OS70-0833/90jlOl0-1128~3.50+.2S/0
Angew. Chem. Int. Ed. Engl. 29 (1990) No. 10
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