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Crown Ether Complexes of Sulfonium SaltsЧThe X-Ray Crystal Structures of [PhCOCH2SMe2╖[18]Crown-6]n[PF6]n and [(PhCOCHPhSMe2)2╖[18]Crown-6][PF6]2.

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BP
',y
Fe \
/Fekco
(0
OC
C,
OC
2
3
u
Scheme 1
terms of Wade's rules[71,2 is an arachno-system which can
be converted into the nido-cluster 3 upon decarbonylation.
3 forms directly in the photochemical reaction of 1 with
alkynes (Scheme 1). In this connection, either the decarbonylation of 1 to afford an unsaturated cluster or the rupture of one of the Fe-Fe bonds can be considered as the
initial reaction; in both cases cycloaddition of the alkyne
ensues. Formation of 3 formally corresponds to the rare
insertion mode of an alkyne into an M-M bond with "parallel" coordination of the alkyne['].
The conversion of 2 into 3 requires reorganization of
the cluster skeleton (Scheme l), which is typical of carbaboranes. This analogy is also corroborated by the structure
of 3, which contains a planar (deviation 1 7 pm), fivemembered organometallic heterocycle with adjusted bond
lengths, and which, according to Wade's rules[71and to the
criteria stated by Hofmann, is isoelectronic in a wider
sense with organoboron 4%-electron ligands such as the
thiadiboroles['ol in 4 (Scheme 2).
[l] K. Knoll, G. Huttner, M. Wasiucionek, L. Zsolnai, Angew. Chem. 96
(1984) 708; Angew. Chem. Int. Ed. Engl. 23 (1984) 793.
[2] K. Knoll, G. Huttner, unpublished.
[3] H.-J. Bestmann, R. Zimmermann in M. Regitz: Methoden der Organischen Chemie (Houben- Weyl), Band E I , Organische Phosphorverbindungen I, Thieme, Stuttgart 1982, p. 622.
[4] N. E. Kolobova, L. L. Ivanov, 0. S. Zhvanko, I. N. Chechulina, A. S.
Batsanov, Yu. T. Struchkov, J. Organomet. Chem. 238 (1982) 223; H.
Berke, Z. Naturforsch. 8 3 5 (1980) 86.
[5] 2 : PZ1/n, a=1259(1), b=1423(1), c=1563(2) pm,p=107.06(6)", Z = 4 ,
2730 reflections, R1=0.048; 3a: Pi, a=881.7(5), b=1063.2(8),
e=1676(1) pm, a=102.21(6), p=92.41(5), y=76.01(6)", Z=2, 3472 reflections, R , =0.025. Distances in the cyclic ligands [pm]: 2 : CC 138(1),
CFe 200.5(6), FeFe 283.3(3), FeP 224.0(3), PC 175.8(7); 3a: CC 141.9(5),
CFe 198.9(3), FeP 217.0(2), PFe 216.7(2), FeC 199.3(4). Distances Fering planes: 2 : 177; 3a: 174 pm. Further details on the crystal structure
investigation can be obtained from the Fachinformationszentrum Energie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen 2, by quoting
the depository number CSD 51 102, the names of the authors, and the
journal citation.
161 T. A. Albright, P. Hofmann, R. Hoffmann, J. Am. Chem. Soc. 99 (1977)
7546.
[7] K. Wade, Adu. Inorg. Chem. Radiochem. 18 (1976) 1.
[8] D. M. Hoffman, R. Hoffmann, J. Chem. SOC.Dalton Trans. 1982, 1471.
Further examples: D. Seyferth, R. S. Henderson, J . Organomet. Chem.
182 (1979) C39 and literature cited therein.
[9] M. Elian, M. M. L. Chen, D. M. P. Mingos, R. Hoffmann, Inorg. Chem.
15 (1976) 1148.
[lo] W. Siebert, R. Full, J. Edwin, K. Kinberger, C. Kriiger, J. Organomet.
Chem. 131 (1977) 1; W. Siebert, Adu. Organomet. Chem. 18 (1980) 301.
[ l l ] G. Huttner, H.-D. Miiller, A. Frank, H. Lorenz, Angew. Chem. 87(1975)
714; Angew. Chem. I n f . Ed. Engl. 14 (1975) 705; G. Huttner, G. Mohr,
A. Frank, Angew. Chem. 88 (1976) 719; Angew. Chem. Int. Ed. Engl. I S
(1976) 682; G. Huttner, J. Borm, L. Zsolnai, J . Organomet. Chem. 263
(1984) C33; H. Lang, G. Mohr, 0. Scheidsteger, G. Huttner, Chem. Ber.,
in press.
I121 W. Hiibel, E. H. Braye, J. Inorg. Nucl. Chem. 10 (1959) 250; P. Y. Degreve, J. Meunier-Piret, M. von Meerssche, P. Piret, Acfa Crysfallogr. 23
(1967) 119; A. A. Hock, 0. S. Mills, Acta Crystallogr. 14 (1961) 139.
Crown Ether Complexes of Sulfonium SaltsThe X-Ray Crystal Structures of
[PhCOCH2SMe2.[181Crown-61,1PF61, and
[(PhCOCHPhSMe& I181Crown-61IPF~1~**
By Billy L. Allwood, John Crosby, David A. Pears,
J. Fraser Stoddart*, and David J. Williams
The recent observation"] that [Ph,PMe][PF,] forms a 2 : 1
complex with [18]crown-6 (18C6) through [C-H. 301 hydrogen bonding has led us to investigate whether alkylsulfonium cations also form discrete complexes with crown
ethers. Complexation should be favored by the fact that
the a-CH group in alkylsulfonium cations, like those in alkylphosphonium ions, are sufficiently acidic to lead toL2]
the formation of stable ylides under basic conditions. We
were also encouraged in our investigation in the knowledge that, even the neutral molecule Me2S02 forms['] a
crystalline 2 : l complex with 18C6 in which the main
source of bonding is undoubtedly [C-H. . .O] hydrogen
bonding. Here, we report on the ability of saltsr4]of the ca+
R
4
3
Scheme 2.
A further notable aspect of the structure of 3 is the incorporation of a trigonal-planar (deviation 5 1 pm) "phosphanediyl"["] into the organometallic heterocycle. With
their conjugated organometallic x-ligands, the complexes
2 and 3 are special cases of an as yet small class of compounds.
Received: June 28, 1984;
revised: August 9, 1984 [Z 904 IE]
German version: Angew. Chem. 96 (1984) 989
Angew. Chem. Int. Ed. Engl. 23 (1984) No. 12
[*I Dr. J. F. Stoddart, D. A. Pears
Department of Chemistry, The University
Sheffield S3 7HF (UK)
[**I
Dr. J. Crosby
Organics Division, Imperial Chemical Industries PLC
Blackley, Manchester M9 3DA (UK)
Dr. D. J. Williams, B. L. Allwood
Chemical Crystallography Laboratory
Department of Chemistry, Imperial College
London SW7 2AY (UK)
The work was supported by the Science and Engineering, and Agricultural and Food, Research Councils in the United Kingdom.
0 Verlag Chemie GmbH, 0-6940 Weinheim, 1984
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977
tions [1]@to [5]' to form crystalline 1 : 1 (polymeric) OT
2 : 1 (discrete) complexes with 18C6I5'.
[Ph,SMe]"
UI"
[PhSMe2]"
t21"
[PhCOCH2SMez]"
[41"
[PhCH2SMe2]"
[3ie
[PhCOCHPhSMe2]"
151"
In the case of the complexes involving [4][PF6] and
[5][PF6], the solid state supramolecular structures, as indicated by X-ray ~rystallography~~~,
reveal that, although the
former exists as a polymeric 1 : 1 structure (Fig. l), the latter is a discrete 2 :1 complex (Figs. 2 and 3).
ring B (and B? is partially disordered, thus precluding definitive assessment of its conformational features. It appears that only one of the methyl groups, namely C( 19)H3,
interacts with an 18C6 ring (A), whilst the other 18C6 ring
(B) experiences an interaction with the methylene group
C(21)HZonly. The methyl group C(24)& does not interact
with ring B despite apparently being directed towards its
center. This may be a contributory factor to the disorder[81
of this ring.
Inspection of space-filling molecular models led us to
suspect that replacement of one of the methylene H atoms
in [4IQby a bulky group, e.g. phenyl, might discourage polymeric complexation. This is so, as demonstrated by the
X-ray crystal structure of the discrete 2 : l complex,
Fig. 1. The supramolecular structure of
14. I 8C6],[PF6]". Ring A experiencesfour, and
ring B two, C - H . . .O contacts of less than
3.4 Distances C . . .0, H . . .O
and angles
C - H . . . O ["I: [C(19)...O(l?]H,: 3.35, 2.43,
163; [C(19).. .0(4)]H,: 3.39, 2.51, 152;
[C(21). . .0(13')]H.: 3.30, 2.37, 164. The two
shortest contacts betwee? the C(24) methyl
group and ring B are 3.29 A between C(24) and
O( 16) but the associated H . ' 0 distance. is
2.94
Me. . .Me
distances
[A]:
C(19). . .C(19'): 3.88; C(24). . .C(24'): 4.53.
[A]
A.
A.
Figure
1 shows
that
the two
18C6 rings
in
[4 .18C6],[PF6],, are situated on crystallographically inde-
pendent centers of symmetry within the unit cell. The cations [4]@are in general positions sandwiched between the
two independent 18C6 rings, which provide different facial
relationships to the cations. Ring A adopts a normal allgauche conformatiod'1 with pseudo DSdsymmetry, whilst
.
[(5)~.18C6][PF& (Fig. 2). The 18C6 ring adopts an allgauche c~nformation'~'
with pseudo D,, symmetry. There
is a crystallographic center of symmetry at the center of the
ring; all four methyl groups are directed towards the ring.
TWOmethyl groups approach axially towards the center of
the ring, whilst the other two bind to the periphery. In both
cases, the contacts to the 0 atoms are long, though in ac-
e
Fig. 2. The supramolecular structure of [(5)2.18C6][PF& The
18C6 ring experiences fen
C - H . . .O contacts- of less than
or equal to 3.5A. Distances
C...O, H...O
and angles
C - H . . . O ["I: [C(lO)...O(l)]H,:
3.50, 2.67, 145; [C(lO). . .0(4)]H,:
3.41, 2.58, 144; IC(l0). . .O(l')]Hc:
3.31, 2.53, 139; [C(lO). . .0(4')]H,:
3.43, 2.61, 143; [C(15). . .0(4)]H,:
3:38,2.60, 139. Me. . .Me distance
[A]: C(l0)-C(l0') 3.80. The
S-C(l0) bond is inclined by 53"
to the normal to the mean plane
of the six-ring oxygen atoms.
[A]
978
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Angew. Chem. Int. Ed. Engl. 23 (1984) NO. 12
ers of this complex is offered. Crystal data: monoclinic, a=9.606(2),
b= 14.872(3), c=38.24(1)
j3=93.10(2)", U=5455
space group
P21/c, z = 4 .
[9] J. A. A. deBoer, D. N. Reinhoudt, S. Harkema, G. J. Hummel, F. de
Jong, J . Am. Chem. SOC.104 (1982) 4073; A. Elbasyouny, H. J. Briigge,
K. von Deuten, M. Dickel, A. Knbchel, K. U. Koch, J. Kopf, D. Melzer,
G. Rudolph, J. Am. Chem. SOC.
I05 (1983) 6568; W. H. Watson, J. Galloy, D. A. Grossie, F. Vbgtle, W. M. Miiller, J. Org. Chem. 49 (1984)
347.
between this H atom-on
[lo] The closest interatomic contact is 2.87
C(39-and C(20) on the phenyl ring.
[Ill D. J. Cram, K. N. Trueblood, Top. Curr. Chem. 98 (1981) 43; K. N.
Trueblood, C. B. Knobler, D. S. Lawrence, R. V. Stevens, J. Am. Chem.
SOC.104 (1982) 1355.
A,
A',
A
Fig. 3. Space-filling representation of [(S),. 18C6I2".
Sacrificial Anodes in the Electrocarboxylation of
Organic Chlorides**
cord with distances observed for similar interaction^['.^^^].
The two phenyl ring planes are orthogonal to each other
(Fig. 3), one adopting a near normal relationship with the
18C6 plane, the other lying nearly parallel (17" between
their mean planes). The closest approach by one of the
18C6 H atoms[101to the mean plane of this phenyl ring is
2.79 A.The axial methyl groups are tilted and involved in
two pairs of bifurcated H bonds to 0(1) and 0(4), and to
O( 1') and O(4'). This binding involves simultaneous complexation by each Me group to both near and far oxygen
atoms of the 18C6 ring, i.e. a cross between a nesting and
perching arrangement["], as distinct from the conventional
perching arrangement observed in [(Me2S0&. 18C61. Although binding differently to the [Ph3PMe]' ion, the cation [5]@can still penetrate the 18C6 cavity.
Received: August 20, 1984 [Z 969 IE]
German version: Angew. Chem. 96 (1984) 987
[I] B. L. Allwood, H. M. Colquhoun, J. Crosby, D. A. Pears, J. F. Stoddart,
D. J. Williams, Angew. Chem. 96 (1984) 806; Angew. Chem. Znt. Ed.
Engl. 23 (1984) 824.
[2] A. C. Knipe in C. J. M. Stirling, S. Patai: The Chemistry of the Sulphonium Group. Part 1, Wiley, Chichester 1981, p. 313.
[3] J. A. Bandy, M. R Truter, F. Vbgtle, Acta Crystallogr. 8 3 7 (1981)
1568.
[4] P. A. Lowe in 121, p. 267; A. J. Speziale, C. C. Tung, K. W. Ratts, A. Yao,
J . Am. Chem. SOC.87 (1965) 3460.
[S] Experimental: [(5)2.18c6][PF&: A solution of [5][PF6] (100 mg, 0.25
mmol) in warm MeOH (5 mL) was added to 18C6 (35 mg, 0.13 mmol)
dissolved in MeOH (2 mL). After 3 h, the crystals which had formed
were filtered off, washed (EtzO), and dried. Yield 109 mg (66%). m.p.
173--175°C. 'H-NMR (CD2C12): 6=2.68 and 3.01 (2x6H. 2 x s ,
2xSMeAMe.), 3.56 (24H, s, IZxOCH,), 6.63 (2H, s, 2xCH), 7.408.04 (16 H and 4 H, m and d, J = 8 Hz, 4 x Ph). Using similar procedures,
the following crystalline complexes were isolated: [( 1)2.18C6][Hg13]2,
m.p. 109-110°C; [(2)2.18C6][Hg13]2,m.p. 143-145°C; [3.18C6],[PF6],, m.p. 123-125°C; [4. 18C6],[PF6],, m.p. 134--135°C.
161 Crystal data: [ 4 . 18C6].[PF6],, triclinic, a = 10.393(1), b= 11.817(1),
c = 12.901(1) A, a = 116.48(1), j3=95.00(1), y=92.94(1)", U = 1406 A3,
space group Pi, Z=2, p-,.= 1.39 g Cm-3.._[(5)2.18C6][PF6]2,
triclinic,
a = 10.455(3), b= 10.589(2), C = 13.803(3) A, a=75.86(2), j3=74.33(2),
y=62.72(2)", U = 1295 A', space group Pi, Z= 1, p..I.= 1.37 g cm-'.
Data were measured on a Nicolet R3m diffractometer with graphite
monochromated CuKa radiation and using the w-scan routine. Both
structures were solved by direct methods and refined anisotropically to
give, respectively, R values of 0.09 and 0.07 for 3255 and 3025 independent observed reflections [O 4 55", lFol> 30(lF01)]. Further details of the
crystal structure investigation can be obtained from the Director of
Cambridge Crystallographic Data Centre, University Chemical Laboratory, Lensfield Road, Cambridge CB2 IEW. Any request should be accompanied by the full literature citation for this communication.
[7] G. Wipff, P. Weiner, P. Kollman, J. Am. Chem. SOC.104 (1982) 3249.
181 The X-ray crystal structure of the complex formed between [3][PF6]and
18C6 was investigated and, although a polymeric 1 : 1 arrangement was
found, the disorder in alternate macrocycles and in the PF? ions, was so
severe that it proved to be impossible to refine the structure below
R =0.201. Consequently, no detailed analysis of the geometric parametAngew. Chem. Int. Ed. Engl. 23 (1984) No. 12
By Giuseppe Silvestri*, Salvatore Gambino,
Giuseppe Filardo and Antonio Gulotta
By and large, the electrochemical carboxylation of organic halides has severely limited application, for the carboxylate ion formed cathodically and the still unreacted
halide react chemically with each other to form an ester['-']
[reactions (1) and (2)]. The yields of the carboxylation can
therefore not exceed 50% even under the most favorable
circumstances.
We wish to report here that in the case of benzylic chlorides it is possible to hinder the esterification by introducing suitable inorganic species into the electrolytic solution.
These species are released by sacrificial anodes and substantially improve the yields of the electrocarboxylation.
Metal ions arising from the anodic reaction (3) form stable
salts with the carboxylate ions which can be isolated on
completion of the electrolysis [reaction (4)].
+ R-X
>- ,
+2eQ+CO2
R-X
-xQ
-XQ
R-COOR
R-COOo
Sacrificial anodes have already been proposed on several occasions for reactions involving carbon dioxide, such
as in the production of oxalic acid (with aluminum[s1and
zincr61)or in the electrocarboxylations of ethylenef7I,acenaphthylenef8I,and, more recently, a series of thioethers9
In all these cases it was possible to perform the syntheses
in diaphragm-less cells, and, in many cases, the salts of the
carboxylate ions could easily be recovered during the
work-up by filtration. The electrocarboxylation of benzylic
chlorides described here also has all these advantages.
The metals to be used as sacrificial anodes must have an
anodic dissolution potential less positive than that of the
oxidation of the organic species present, or to be formed,
in the electrolytic medium, and the metal ions released in
the electrolytic solution should not to be reduced at the cathode. Aluminum, zinc, and magnesium gave satisfactory
results; the most reliable for large-scale electrolyses, how[*] Prof. Dr. G. Silvestri, Prof. Dr. S. Gambino,
Prof. Dr. G. Filardo, Dr. Eng. A. Gulotta
Istituto di Ingegneria Chimica dell'universita di Palermo
Viale delle Scienze, 90128 Palermo (Italy)
[**I This work was supported by Consiglio Nazionale delle Ricerche-Progetto Chimica Fine e Secondaria, Rome.
0 Verlag Chemie GmbH. 0-6940 Weinheim, 1984
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