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CsF╖Br2 an Alkali-Metal Halide Intercalation Compound.

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nique: empirical absorption correction, bi = 141.5 cm-l. eight reflections.
decomposition, - 18.9% f in 77 3 h for tlireecontrol reflections. isotropic correction, extinction. i: = 0.3526 x lo-'. corrected: hydrogen atoms
caculated for ideal geometry (d(C-H) = 95 pm) and included in the calculation of the structure factors with a collective isotropic temperature factor
per C atom but not refined. Anomalous dispersion was taken into consideration Shiftlerror < 0.01 in the last cycle of refinement: residual electron
2.58 e , , k 3 for 85 pm and - 2.77 e,&' for 91 pm distance
density:
from osmium atoin. IR [cm-'1: I ~ O S O=) 904 vs (CS,). X68 vs (KBr).
' H N M R (400 MHL, C,D,, 20 C): 6 = 3.91 (s. 6 H : CH,) 8.35 (m, 2 H :
CH). 6.79 (m. I H: CH). 6.51 (m, 2 H : CH). ( ' H ) ' ' C N M R (100.5 MHz.
C,D,. 20 C). 6 = - 10.74 (CH,). 124.6, 139.0, 147.1 (CH). "ONMR
(54.2 MHz. C,H,. 20'C. external standard H,O): 6 =745. FD-MS
(CH,CI,, "*Os): mlz 333 (monomer; rel. int ll'h).
[12] 5. red crystals, dcc. above ca. 150 C, sublimable at 50 Ci760 Torr. IR
(KBr) [cm-'] (e(0sO. term.) = 950 vs. v(Os0. ester) = 634 m. ' H NMR
(400 MHz. C,D,. 20 C): 6 = 0.93 ( s , 6 H ; CCH,), 1.27 ( s . 6 H : CCH,),
3.87 ( s . 6 H : OSCH,). "CNMR (100.5 MHz. C,D,. 20 C): 6 = 18.28
(OsCH,), 24.63 (CCH,). 25.80 (CCH,). 90.94 (CCH,) "ONMR
(54.2 MHz. pentane, 20 C. external standard H,O): B = 675. El-MS
(70eV. i920s):m i ; ( M @ ,5 % )
(131 Further details of the crystal structure investigation o f 3 a and 4 may be
obtained rrom the Fachinformationszentrum Karlsruhe, Gesellschaft fur
wissenschaftlich-technische Information inbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-54862, the
names of the authors and the journal citation.
[14] W. A. Herrmann, P. Watzlowik. P. Kiprof, unpublished results 1990.
+
which is almost unchanged from the Raman line of elemental
Br, (317 cm-I). No BrF stretching vibration could be seen.
In the case of CsF . Br,, we succeeded in growing single
crystals and carrying out an X-ray analysis (Fig. 1). Much to
our surprise the compound is a cesium fluoride intercalation
compound with Br, as guest. The NaC1-typecesium fluoride
lattice has opened along the (100) planes and the Br, molecules are stacked between the planes. The cesium and fluorine atoms are arranged in an eclipsed manner along [IOO],
resulting in a primitive tetragonal cell. The Br-Br distance of
232.4pm is only slightly longer than that in elemental
bromine (228 pm) and the Br . . F' contacts (252.1 prn) are
about 4 0 % longer than a normal Br-F bond (180 f 10 pm).
Any covalent bonding here must be very weak.
CsF-Br,, an Alkali-Metal Halide Intercalation
Compound **
By Darryl D. DesMarteau.* Thomas Grelbig,
Sun-ffee ffwang, and Konrad Seppelt
Cesium fluoride is one of the strongest fluoride catalysts,
since it combines a very large cation and a very small anion
in a simple NaC1-type lattice. Therefore, the salt has a strong
tendency to "increase" the size of its anion by forming intermediate or permanent anionic fluoride complexes. There are
a large number of complex cesium fluorides CS:AF:,
where
A can be almost any element of the periodic system. Many
of their structures are known.
In the reactions of fluorinated nitriles with bromine in the
presence of CsF, the C s F was found to absorb bromine,
which was not readily removed at room ternperature.['*'I
Subsequent investigation revealed that CsF can absorb both
Br, and I, to form complexes in which the ratio CsF:X, is
1 : I and 2:1.[31 The CsF.Br, complex is very effective in
oxidizing fluorinated nitriles and imines to N-bromo derivatives as well as in converting N-CI bonds into N-Br bonds
in N,N-dichloroamines." - 3 1 This reactivity, combined with
the novelty of the CsF-halogen complexes, made their structure determination of interest.
The halogen-rich 1 : 1 phases are formed with excess halogen at room temperature, and the 2: 1 materials can be prepared by prolonged pumping at lo-' mbar on the 1 : I
phases. The supposition that the 1 : 1 materials might contain
the polyhalide ions [Br-Br-F]' and [I-I-FIO (cf. Br?, BrFF,
IClF, CI,F') was not in accord with the Raman spectra of
CsF-Br,, since it shows only one line at i;= 292.5 c m - ' ,
[*] Prof. D D. DesMarteau, S.-H Huang
Department of Chemistry. Clemson University
Clemson, SC 29631 (USA)
Prof. K . Seppelt, T. Grelbig
Institut fur Anorganische und Analytische Chemie der freien Universitit
Fabeckstrasse 34-36, D-1000 Berlin 33 (FRG)
['*I
Fig. 1. Crystal structure o f C s F . Br, (two adjacent unit cells). The orange crystals were grown from CsF in a large excess of elemental bromine at 80°C in a
glass ampoule over four weeks. Enraf-Nonius CAD-4 diffractometer.
T = - 153'C, Mo,,. graphite monochromator, 4 2 8 scan, DIFABS absorption correction. SHELX. full matrix, P4/nimn? (No. 123). u = 417.7(2),
c =736.4(2) pm. V = 128.5 x 10' pm', Z = 1. Reflections: 886 measured, 287
independant, 264 with I > 341) within 2 5 0 i 4 0 . R = 3.15, R, = 2.6. Further details of the crystal structure investigation are available on request from
the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftliche
und technische Information mbH. D-7514 Eggenstein-Leopoldshafen2
(FRG). on quoting the depository number CSD-54259. the names of the authors. and the journal citation.
If one considers the NaCl lattice to be very stable, this
reaction is very surprising. But Madelung lattice energy calculations (MAPLE)t4] on CsF show that cleavage along
(100) results in loss of only 6 % of the energy; which explains
the cleavability parallel to (100) for such crystals. If entropic
terms are disregarded, this small loss of electrostatic energy
could be compensated for by even very weak Br . . . F' interactions, which could amount to only a few kJ mol-'.
The coordination of the CsQ ions is square planar and the
Cs' . . Fa distance of 300.1 pm in cesium fluoride is reduced to 294.0 pm in CsF . Br,. This is virtually identical to
the CsQ . . F@distance of 293.6 pm in the high-pressure CsF
(CsCI-type) modification (48 k b ~ ) . [If~ the
] bromine atoms
at a distance of 388 pm are included in the coordination of
CsQ, the coordination number is 12 and the coordination
polyhedron a square-based column.
Whether these features are retained in CsF.1, and whether
the 2: 1 phases are intercalates where only every second layer
is filled remain speculation until structural data are available.
This work was supported by the Fonds der Chemischen Industrie and the
Alexander von Humboldt Stiftung. We thank Prof. G. M e w r . Hannover,
for help with the MAPLE calculations.
1448
Q VCH V ~ . r l u g . s ~ ~ ~ . s e l lmhH.
~ c h u / ~W-6940 Weinh<>.irn,
1990
0570-0833!90~1212-1448
.$3.50+ .25jO
Received. July 2. 1990 [Z 4048 IE]
German version: Angeii. Chern. 102 (1990) 1519
Angels. Chem. I n t . Ed. Engl. 29 119901 No. 12
CAS Registry numbers.
C s F - Br,. 130147.1 1-4; CsF.1,. 130147-12-5; 2CsF.Br2, 130147-13-6;
2CsF- I ? , 130147-14-7;CsF, 13400-13-0; bromine, 7726-95-6; iodine, 7753-562.
[I] B. A. OBrien. D. D. DesMarteau, J Org. Chem. 49 (1984) 1467.
[2] Y. Y Cheng, Q. C. Mir, B. A. O'Brien, D. D. DesMarteau. Inorg. Chem. 23
(1984) 518
[ 3 ] S. Y Huang, Ph. D. Thesis, Clemson University, South Carolina, USA
1990.
[4] R Hoppe. Angen. Chem. 78(1966) 52; Angew. Chem. Inr. Ed. Engl. 5(1966)
95; ibrd. 82 (1970) 7 bzw. 9 (1970) 25.
[S] C. E. Weir, G. J. Piermarini, J. Res. Nut/. Bur. Stand. Secr. A 68 (1964) 105.
taining Pt +Ag bonds, since the basic platinum centers enable them to act as donor atoms to the electrophilic silver
ions in silver salts (AgCIO,, AgNO,) or silver complexes
such as [0,C10AgPPh,].[31 Therefore, we have explored the
use of anionic platinum(rr) derivatives as Pt-donor ligands
towards other electrophiles. Here we describe the synthesis
of an unprecedented tetranuclear cluster containing three
Pt" + Sn" bonds unsupported by any covalent bridging ligands; the Sn" center is only linked to three Pt" atoms and
additionally displays short contacts to several o-F atoms of
pentafluorophenyl groups.
Addition of SnCI, and AgCIO, to a THF solution of the
Pt complex 1[,] at room temperature leads to precipitation of
AgCl. The tetranuclear complex 2 can be obtained from the
filtrate in 75% yield [Eq. (I)].
1.5(NBu4),[Pt,(~-C1),(C,F,),]
(NBU,)[S~(P~(~-C~)(C~F~)~)~J,
an Unusual
Cluster with Three Pt" + Sn" Bonds **
THF
1
2AgCli
(1)
+ 2NBu4CI0, + (NBu,)(Sn{ Pt(p-CI)(C6F5),}J
By Rafael Usan,* Juan Forniks, Milagros Tomas,
and Isabel Usdn
The insertion of SnClz into M-CI bonds to give
CI,Sn --* M bonds is well documented.['] Adducts of the general type [CI,Sn(M(PMe,),Cl),] (M = Rh, Ir), displaying
two M + SnCI, bonds have been prepared recently and the
structure of the rhodium complex has been solved by X-ray
cry~talIography.[~]
But, to the best of our knowledge, no
complexes with bonds from a Pt" moiety to an otherwise
bare Sn" center have, so far, been reported.
+ SnCl, + 2AgCI0,
2
It is important to strictly maintain the given stoichiometry, since an excess of AgC10, also precipitates the bridging
chloride ligands between the Pt" atoms, leading to decomposition.
The structure of 2 has been established by a single-crystal
X-ray study.[51The unit cell (space group Cc) contains, in
addition to the corresponding cations, two types of independent anions of the same composition (A and B) with very
Fig. 1. Molecular structure of the anion in 2. Selected bond lengths [A] and bond angles ["I:anion A: Sn(1)-Pt(1)2.732(2), Sn(l)-Pt(2) 2.742(3), Sn(l)-Pt(3) 2.704(2),
Pt(l)-CI(l) 2.414(6), Pt(l)-C1(3) 2.373(7), Pt(2)-C1(3) 2.401(7), Pt(2)-Cl(2), 2.415(6), Pt(3)-C1(2) 2.372(7), Pt(3)-CI(l) 2.426(8), Pt(l)-C(49) 2.029(23), Pt(l)-C(55)
2.068(23). Pt(2)-C(61) 1.943(19), Pt(2)-C(67) 1.968(23), Pt(3)-C(37) 1.981(24), Pt(3)-C(43) 2.028(24); Pt-Sn-Pt 87.7(30); Sn(l)-F(42) 2.9996(150), Sn(l)-F(44)
3.2526(366). Sn(1)-F(50) 2.9706(184), Sn(l)-F(60) 3.0491(132), Sn(l)-F(66) 3.0882(138), Sn(l)-F(72) 3.0946(153).anion B: Sn(2)-Pt(4) 2.733(2), Sn(2)-Pt(5) 2.703(3).
Sn(2)-Pt(6) 2.734(2), Pt(4)-C1(4) 2.439(7), Pt(4)-C1(6) 2.417(7), Pt(5)-C1(4) 2.386(7), Pt(5)-C15 2.404(7), Pt(6)-C1(5) 2.422(7). Pt(6)-C1(6) 2.396(7), Pt(4)-C(25) 1.989(25),
Pt(4)-C(31) 1.960(23), Pt(S)-C(l) 2.007(23), Pt(5)-C(7) 2.048(23), Pt(6)-C(13) 1.957(23), Pt(6)-C(14) 1.962(27); Pt-Sn-Pt 88.1(9); Sn(2)-F(6) 2.8887(137), Sn(2)-F(8)
3.1309(132), Sn(2)-F(18) 3.0643(161), Sn(2)-F(24) 3.1668(133), Sn(2)-F(26) 3.0035(160), Sn(2)-F(32) 3.1930(136).
During the last few years we have shown that anionic
pentahalophenyl complexes of platinum(I1) are suitable precursors for the synthesis of heteronuclear complexes con[*] Prof. R. Uson, Prof. J. Fornies, Dr. M. Tomis, I. Uson
Departamento de Quimica Inorganica Instituto de Ciencia de Materiales
de Aragon
Universidad de Zdragoza.
E-50009 Zaragoza (Spain)
I**] We are grateful to the Spanish Cornisinn Interministerial de Ciencia y
Tecnologia (CICYT) for financial support (project PB88-0076) and for a
F o r m a c i h de Personal Investigador (F.P.I.) grant to Z.U.
A17gen. C'hmi. Inr. Ed. Engl. 29 (19901 No. 12
similar central cores but different orientations of the C,F,
groups (Fig. 1).
The cluster can be described as a [Pt,(~-CI,)(C,F,),13~
unit with a six-membered, puckered Pt,CI, ring in which the
three Pt atoms are interconnected by three chloride bridges
and linked to the Sn" atom by platinum-to-tin donor-acceptor bonds. Thus, the Pt,CI, moiety acts as a tridentate ligand
to the Sn atoms. Each platinum atom has square-pyramidal
coordination with an apical Sn atom; the basal plane is defined by the ipso-C atoms of two C,F, groups and two chloride ligands and the Pt-Sn bonds form angles of 10.63-
,T) VCH Verlrrjis~rc.ell.~cha~
mhH. W-6940 Weinheim. 1990
0570-083319011212-1449S 3 . 5 0 f -2510
1449
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compounds, br2, metali, intercalation, halide, alkali, csf
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