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Molecular Self-Assembly to Give the Antiferromagnetic Cage Compound [{CpFe(CO)2(Mes)PO2}4{MesPO3Fe2(OH)Cl}2].

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decarbonylated to iron(II1) centers with concomitant loss of the
Cp ligand. The phosphorus centers are oxidized to phosphinato
(Fp(Mes)PO;) and phosphonato (MesPOi-) ligdnds. Surpris[~C~Fe(CO)~(Mes)PO~~~~MespO~Fe~~O
H)C1)zI** ingly a neutral polyhedron framework formed consisting of four
iron(nr) and six phosphorus centers, which are connected
Ingo-Peter Lorenz,* Wolfgang Pohl, and
through 0 bridges. To each phosphorus atom a Mes group is
Heinrich Noth
bound, to four of them a CpFe(CO), fragment is also attached
Dedicated to Pr?fessor Joachim Strahle
(two MesPOZ- and four Fp(Mes)PO;).
on the occasion of his 60rh birthday
The analytical and spectroscopic characterization of 2 does
not give any useful indications toward the composition and
The basis of chemical research is the planning and execution
structure. The IR spectrum (solid/KBr) of 2 shows absorptions
of rational syntheses of interesting materials with defined funcfor mesityl and Cp ligands, two strong absorptions for v(C0) at
tionality. However, many reactions don't yield the desired
2028 and 1980 cm-', and surprisingly two additional absorpproduct but often lead to surprising novel compounds. In the
tions for v(P0,) at 1059 and 974 cm-' as we11 as a weak absorpconstruction of structures of high complexity from simple buildtion for v(0H) at 3559 cm-'. The 31P(1H}NMR spectrum (in
ing blocks chance frequently plays the role of the architect. The
[D,]DMSO) shows two broad signals at 6 = 138.4 and 15.3 in a
self-assembly of chemical systems is particulady appealing, and
1 :2 ratio. The 'H NMR spectrum (in [D,]DMSO) reveals slightrecently Miiller et al. synthesized an unusually large host-guest
ly broadened signals at 6 = 5.3 (for Cp, s) as well as at 7.3, 2.2,
complex from a solution containing eight components; one of
2.1 (for Mes, each s); the signals of the protons of the p3-OH
which was a phosphonate."] We report here on a very simple
groups were not observed (see below). The highest mass detectand surprising oxidative conversion of a diorganometalated
ed by FAB mass spectrometry appeared at mi; 2090, which is
phosphonium salt with two iron(I1) centers to a molecule conassumed to be the chloride-free fragment [ M - 2C1]+; in containing eight iron centers (four Fe" and four Fe"') that are held
trast, the elemental analysis reveals the presence of a chloridetogether by two tridentate phosphonato and four bidentate
containing species.
phosphinato ligands.
The structure and composition of 2 was clarified by a singleIn our investigations on organometalated phosphorus comIt shows there
crystal X-ray structure analysis (Figure
pounds."' which obey the isolobal principle, we have prepared
the P-H functional diferriophosphonium salt l a via the nonisolable intermediate [{ CpFe(CO),},PCIR]CI (l'a) (R = mesityl
(Mes)) by using [(CpFe(CO),},] ( = Fp,) and RPCl, .[31 Exposure of a solution of l a in acetonitrile or acetone to aerial
oxidation afforded yellow crystals of 2 (R = Mes) reproducibly
[Eq. (a)]; ferrocene forms as a by-product. In case of R = Me,
iPr, Ph, the corresponding P-Cl functional diferriophosphonium salts can be isolated and characteri~ed;~~]
their P-CI function can be subsequently modified.[41
3
The simple aerial oxidation of 1 a has radical consequences:
Some of the iron(rr) centers of l a are completely oxidatively
Molecular Self-Assembly to Give the
Antiferromagnetic Cage Compound
TC6'
I
CI
ChCN
6
-16CO
\'"CO
co
- 4 HCI
la
Figure 1. Molecular structure of 2 in the crystal. The mesityl groups (with exception
of the @so-Catoms) and the ligands Cp and CO at the iron atoms were omitted for
clarity. Selected bond lengths [A] and angles ("I: Fe2-02 1 929(6), Fe2-010
1.932(6), Fe2 - 0 3 2.008(7), Fe2- 0 9 2.01 5(7), Fe2 - OX 2.123(7), Fe4 - 0 8 2.168(7),
- 4 CplFe
M"
Fe4-Ola 1.883(7), Fe4-04 1.908(7), Fe4-05 1.884(7), Fe4 - CIl 2.346(7), P3-0.
1 534(7)- 1.546(7), P2 -0. 1.544(7)- 1.561(7), P2 - Fe3 2.26 l(3); 02-Fe2-010
95.6(3), 08-Fe2-08a 81.7(2), Fe2-08-Fe2a 98.3(3), Fe2-08-Fe4 123.0(3). P3-0.Fen 124 514)-127.6(4), P2-On-Fe, 136.0(4)-142.0(4).
I
2
we%
['I Prof. Dr. I.-P. Lorenz, Dr. W. Pohl, Prof. Dr. H. Noth
[**I
lnstitut fur Anorgdnische Chemie der Universitat
Meiserstrdsse 1. D-80333 Miinchen (Germany)
Fax: Int. code +(89)5902-258
e-mail : ipl(o anorg.chemie.uni-muenchen.de
We thank the Fonds der Chemischen Industrie for financial support, the FreiStadt Bayern for a doctoral grant for W. P., and Prof. Dr. G. Pausewang,
Universitit Tiibingen, for the magnetic measurements.
A n p u , . Chmi. I n t .
Ed. Engl. 1997. 36, No. 112
G
is a central cage framework consisting of two edge-sharing
FeO,(OH) octahedrons, which are connected through the
common p3-OH bridges to two further, trigonal-bipyramidalconfigurated iron centers. These trigonal bipyramids are mostly
0-coordinated with one apical chloro ligand (FeO,(OH)Cl) .
Compound 2 has a crystallographically-imposed inversion
center. All 0 bridges stem from tetrahedrally coordinated phosphorus ligands, two p3-MesPO:- and four p,-Fp(Mes)PO;
ligands. These together with the two chloride and two hydroxide ions provide 12 negative charges and act, with the
exception of the C1- ion, as bridging ligands for the four
Fe"' centers.
YCH Yerlagsgesellschaj~mbH, 0-69451 Weinheim. 1997
0570-0833/97/3601-0055
S iS.OO+ .2S/O
55
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Depending on the donor ligand the average F e - 0 distances
in the double octahedron are about 1.93 A (FpP(Mes)O,),
2.011(7) A (MesPO,), and 2.123(7) 8, (p3-OH). The equatorial
angles 02-Fe2-010 and 08-Fe2-08a were determined to be
98.9(3) and 81.7(2)", respectively. The atoms Fe2,08, Fe2a and
0 8 a lie in one plane and form a rhombus with the acute angle
at the iron atoms; thus, a bonding interaction between Fe2 and
Fe2a i s not possible (distance Fe2-Fe2a = 3.212 Aj. The trigonal-bipyramidal coordination of Fe4 is slightly distorted. The
longest F e - 0 distance in 2 was determined for Fe4-08(apical)
to be 2.168(7)A, the shortest for Fe4-0, (equatorial) to be
about 1.895 A. The equatorial bridges 04,05, and O l a are bent
slightly out of the ideal plane. The Fe4-Cl1 distance is
2.346(3) A. The bond angles at the 0 bridges lie between
124.5(4) and 146.7(4)", those at the P atoms (103.8(4)113.1(3)") have values close to the tetrahedron angle. The sum
of angles Fe-0-Fe at the trigonal-pyramidal pu,-OHbridges is
345.3'; the p,-OH hyrogen atom does not participate in any
hydrogen bonding.
Temperature-dependent magnetic measurements for 2 revealed antiferromagnetic behavior with a Nee1 temperature of
40 K ; the bond lengths (Fe-0) and angles (Fe-0-Fe) of the
four central Fe"' ions (Fe2, Fe2a, Fe4, Fe4a) allow superexchange and spin orientation. At 300K the peff value was
5.48 BM.[61
The mild aerial oxidation of the diferriophosphonium salt l a
leads to many (sometimes drastic) changes in the functionality
at both the iron and phosphorus atoms: We find both retention
and elimination of the CpFe(CO), groups as well as complete
oxidation to give iron(in) centers, and oxidation of the phosphonium building blocks to give p,-phosphinato and p3-phosphonato ligands. This wide palette of new building blocks finally
readily combines to form 2. The new molecular framework of 2
is illustrated by the polyhedral representation in Figure 2. The
structure contains a central double octahedron (FeO,(OH)), ,
two trigonal bipyramids (Fe03(0H)Cl), and six tetrahedrons
(four Fp(Mes)PO, and two MesPO,). Compound 2 is an example for the unusual combination of classic (in the corej and
organometallic complex chemistry (at the periphery). We are
currently investigating similar organometalated sulfonium
salts,['' which also may be converted to similar coordination
polyhedrons with sulfenato, sulfinato, and sulfonato ligands by
aerial oxidation.
Experimental Section
Synthesis of la see reference [3].
2: la (200 mg, 0.37 mmol) was dissolved in acetonitrile (12 mL) and this solution
was exposed to air for three days. Small yellow crystals formed on the inside glass
surface. They were collected and washed with acetone. Yield: 30 mg (22.4%). Additional quantities of 2 remained ~nthe mother liquor; however, these could not be
isolated in a pure fom; correct elemental analysis. Compound 2 is soluble only in
dimethyl sulfoxide (DMSO)
Received: May 20. 1996
Revised version: September 26, 1996 [Z9132IE]
German version: Angeir.. Chem. 1997, 109, 55-56
Keywords: cage compounds
P ligands self-assembly
-
*
iron
-
magnetic properties
[I] A. Miiller, K. Hovemeier, E. Krickemeyer, H. Bocke, Angew. Chem. 1995,107,
856; Angew. Chem. In[. Ed. Engl. 1995,34,779; further examples for molecular
self-assembly can be found in J.-M. Lehn, Supermolecular Chemisrry: Concepts
and Perspectives, VCH, New York, 1995.
[2] a) W. Pohl. I.-P. Lorenz, H. Noth, M. Schmidt, Z. Naturforsch. 5 1995, SO,
1485; b) I.-P Lorenz, P. Miirschel, W. Pohl, K. Polborn, Chern. Ber. 1995,128,
441; c) I.-P. Lorenz, W. Pohl, K. Polborn, ihid. 1996, 129, 11.
[3] ILP. Lorenz. W. Pohl, H. Noth, M. Schmidt. .
I
Organornet. Chem. 1994, 47S,
211.
[4] W. Pohl, PhD Thesis, University of Miinchen, 1995.
[ S ] X-ray structure analysis of 2: C8,H8,CI,Fe,02,P,, brown plates, 0.30 x 0.26 x
0.1 mm', triclinic, space group P , u = 12.991(7), b = 14.660(7), c = 14.7?6(7) A,
x=119.25(1), 8=106.41(2), ~=94.88(1)', 2 = 2 , V=2270(2)A3, pcSicd=
1.581
p =1.476mm-l, F(OO0) =1104, diffractometer: Siemens P4,
Mo,, (1. = 0.71073 A), T = 213 K, 28 = 3.24-47.00, w scan, scan range (0)
1.2'. reflections: 5241 measured, 4967 of which were independent
(R(int) = 0.1251), 3022 observed [F>4o(F)]. The structure was solved with the
programs XS (Siemens) and SHELXL (G. M. Sheldrick, Gottingen, 1993)by
direct methods and refined by full-matrix least squares refinement. The hydrogen atoms were refined as riding atoms with fixed isotropic temperature parameters. 553 refined parameters, R = 0.0693, nR2 = 0.1308, GOOF = 1.049. Further details of the crystal structure investigation may be obtained from the
Fachinformationszentrum Karlsruhe, D-76344 Eggenstein-Leopoldshafen
(Germany), on quoting the depository number CSD-405885.
161 The measurements of magnetic susceptability were made between 10-300 K
with 20 mg of microcrystalline 2 on a Quantum Design MPMS Squid magnetometer at a field strength of 2 T Calculations (without diamagnetic correction)
were made with one molecule of CH,CN per molecule of 2.
[?I 1:P. Lorem, K . Thurow, J Orgunornrc. Cliem. 1995,496, 191.
Linear Pentanuclear Complexes Containing a
Chain of Metal Atoms: [Co:'(pu,-tpda),(NCS),]
und [Ni:'(p5-tpda),C1,1**
Shen-Jye Shieh, Chin-Cheng Chou,
Gene-Hsiang Lee, Chih-Chieh Wang, and
Shie-Ming Peng*
Metal-metal bonding in dinuclear metal complexes is well
understood.[' - 31 Our efforts to extend dinuclear metal complexes to form trinuclear metal complexes with a syn-syn bis[*I Prof. S.-M. Peng, Dr. S.-J. Shieh, C.-C. Chou, G.-H. Lee, Dr. C.-C. Wang
Figure 2. Polyhedral representation of 2, consisting of two edge-shared octahedrons ([FeO,(OH)],), two trigonal bipyramids (FeO,(OH)CI), and six tetrahedrons (four Fp(Mes)PO, and two MesPO,).
56
8 VCH VerlagsgeseflschaftmbH, 0-69451 Weinhelm, 1997
["I
Department of Chemistry
National Taiwan University
Taipei, Taiwan, 107 (Republic of China)
Fax: Int. code + (2)3636359
This research was supported by the National Science Council of Taiwan.
(H,tpdd = N,N'-bis(i-pyridyl)-2,6-diaminopyridine).
0570-08337j97/3601-0056
S IS.00f .2S/0
Angen. Chem. Inr. Ed. Engl. 1997, 36, No. ljZ
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