Trinuclear oxo-centered iron and iron/nickel clusters - Ligand-controlled homo/hetero valency

Article abstract of DOI:10.1002/ejic.200400821

Cleavage of the all-iron(III) μ₂-O^2--linked dimer [Fe^III3O(L)₂-(OAc)₄]₂O (3) with lithium chloride yields [Fe^III3O(L)₂-(OAc)₄]Cl (4) and with sodium benzoat

Full text of DOI:10.1002/ejic.200400821

FULL PAPER
Trinuclear Oxo-Centered Iron and Iron/Nickel Clusters – Ligand-Controlled
Homo/Hetero Valency[‡]
Rolf W. Saalfrank,*[a] Andreas Scheurer,[a] Klaus Pokorny,[a] Harald Maid,[a]
Uwe Reimann,[a] Frank Hampel,[a] Frank W. Heinemann,[b] Volker Schünemann,[c] and
Alfred X. Trautwein[d]
Keywords: Trinuclear complexes / Iron / Nickel / Mixed-valent complexes / Heteronuclear complexes
Cleavage of the all-iron(III) μ2-O2–-linked dimer [FeIII3O(L)2-
(OAc)4]2O (3) with lithium chloride yields [FeIII3O(L)2-
(OAc)4]Cl (4) and with sodium benzoate, in combination with
complete acetate-to-benzoate coligand exchange, gives
[FeIII3O(L)2-(OBz)4]OBz (5). Reduction of the all-FeIII complex
5 [Fe/L/OBz = 3:2:(4+1)] with sodium iodide affords the
homonuclear mixed-valent cluster [FeIIFeIII2O(L)3(OBz)3] (6)
(Fe/L/OBz = 1:1:1) and requires fundamental coligand-to-li-
gand exchange. Likewise, when the all-FeIII dimer [FeIII3O-
(L)2(OAc)4]2O (3) (Fe/L/OAc = 3:2:4) is cleaved with nickel
acetate, the mixed-valent heteronuclear complex [NiIIFeIII
-
2
O(L)3(OAc)3] (7) (M/L/OAc = 1:1:1) is formed.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
Introduction
Recently, we reported that the reaction of N-(5-meth-
ylthiazol-2-yl)thiazole-2-carboxamide HL (1) with fresh
iron(ii) acetate in fluorobenzene under aerobic conditions
yields the deeply violet μ3-O2–-centered mixed-valent com-
plex [FeIIFeIII2O(L)3(OAc)3] (2), whereas aged Fe(OAc)2 in
chloroform under aerobic conditions leads to homovalent
dimer [FeIII3O(L)2(OAc)4]2O (3) (Scheme 1).[1–4] Most no-
tably, the metal/ligand/coligand ratio (Fe/L/OAc) in mixed-
valent 2 is 1:1:1, whereas the ratio in homo-valent 3 is 3:2:4.
Results and Discussion
All-Iron(III) Complexes
Scheme 1. Synthesis of heteroleptic 2 and 3. In 2, the mixed valency
and its statistical distribution is highlighted by differently marked
segments.
Herein we describe the cleavage of the μ2-O2–-linked di-
mer [FeIII3O(L)2(OAc)4]2O (3) in chloroform with lithium
chloride or sodium benzoate to give [FeIII3O(L)2(OAc)4]Cl
(4) or [FeIII3O(L)2(OBz)4]OBz (5) (Scheme 2). The cleavage
of 3 with benzoate ions to give 5 obviously proceeds with
complete acetate-to-benzoate coligand exchange.
The all-iron(iii) character of 4 and 5 was confirmed by
Mössbauer spectra of their powder samples recorded at
77 K. The spectra exhibit quadrupolar doublets and iso-
meric shifts consistent with high-spin iron(iii) (4: ΔEQ
=
[‡] Chelate Complexes, 30. Part 29: Ref.[1]
[a] Institut für Organische Chemie der Universität Erlangen-
Nürnberg,
0.77 mms–1, δ = 0.48 mms–1, and Γ = 0.36 mms–1; 5: ΔEQ
= 0.77 mms–1, δ = 0.51 mms–1, and Γ = 0.45 mms–1). The
Mössbauer spectrum of 5 is displayed in Figure 1 as an ex-
ample.
Henkestrasse 42, 91054 Erlangen, Germany
Fax: +49-9131-852-1165
E-mail: saalfrank@chemie.uni-erlangen.de
[b] Institut für Anorganische Chemie der Universität Erlangen-
Nürnberg,
The structure of 4 was unequivocally determined by sin-
gle-crystal X-ray analysis.[5–7] According to these data, het-
eroleptic [FeIII3O(L)2(OAc)4]Cl (4) is made up of two di-
topic, tridentate ligands (L)– and four bridging acetate co-
ligands, fixing the three FeIII ions in the corners of a tri-
angle with a μ3-O2– ion in the center. Fe1/2 are linked by
91058 Erlangen, Germany
[c] Fachbereich Physik, Technische Universität Kaiserslautern,
67663 Kaiserslautern, Germany
[d] Institut für Physik der Medizinischen Universität Lübeck,
23538 Lübeck, Germany
[‡] Chelate Complexes, 30. Part 29: Ref.[1]
Eur. J. Inorg. Chem. 2005, 1383–1387
DOI: 10.1002/ejic.200400821
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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R. W. Saalfrank et al.
FULL PAPER
Since we were not successful in growing single crystals
suitable for an X-ray analysis of [FeIII3O(L)2(OBz)4]OBz
(5), we prepared [FeIII3O(L)2(OBzBr)4]OBzBr (9). The all-
iron(iii) complex 9 was synthesised from iron(ii) acetate
with an excess of sodium 4-bromobenzoate and N-(5-meth-
ylthiazol-2-yl)thiazole-2-carboxamide HL (1) in chloroform
under aerobic conditions, and separated from mixed-valent
[FeIIFeIII2O(L)3(OBzBr)3] (10) by fractionising crystalli-
zation (Scheme 3). According to the X-ray analysis, 9 is iso-
structural with [FeIII3O(L)2(OAc)4]Cl (4) with one μ1-
(OBzBr)– coligand bound to Fe, necessary for coordination
and charge compensation (9: ΔEQ = 0.81 mms–1, δ =
0.48 mms–1, and Γ = 0.35 mms–1).[6–8]
Mixed-Valent Homonuclear and Mixed-Valent
Heteronuclear Complexes
The reversible cyclic voltammograms of redox-active
[FeIIFeIII2O(L)3(OAc)3] (2) and [FeIIFeIII2O(L)3(OBz)3] (6)
displayed basically two processes attributable to the re-
duction of 2 and 6 from FeIIFeIII to FeII2FeIII and oxi-
2
dation to the all-FeIII species.[1] The number of electrons
transferred at different potentials during this process was
determined in acetonitrile vs. Fc/Fc+ and turned out to be
one for the reduction of all-FeIII to FeIIFeIII and one for
2
the second reduction to FeII2FeIII. Further reduction of
FeII2FeIII to the all-FeII species is irreversible. Consequently,
the cyclic voltammograms of redox-active [NiIIFeIII2O(L)3-
(OAc)3] (7) and [NiIIFeIII3O(L)3(OBz)3] (8) represent the re-
duction of NiIIFeIII to NiIIFeIIFeIII and reoxidation to
2
NiIIFeIII
.
As determined in acetonitrile vs. Fc/Fc+, one
[1]
2
Scheme 2. Synthesis of 4–8. In 5 the monodentate and bidentate
(OBz)– coligands substituted in 6 by ditopic, tridentate (L)– are
highlighted (diagonal). In 6–8, the mixed valency and its statistical
distribution are emphasised by differently marked segments.
electron is transferred during this redox process. Further
reduction of NiIIFeIIFeIII to the NiIIFeII2 species is irrevers-
ible.
Reduction of the all-iron(iii) complex [FeIII3O(L)2(OBz)4]-
OBz (5) in chloroform with 5 equiv. of sodium iodide[9]
yields homonuclear mixed-valent cluster [FeIIFeIII2O(L)3-
(OBz)3] (6) (Scheme 2). Worth noting is that reduction of 5
does not simply occur by a one-electron reduction, but
rather affords fundamental coligand-to-ligand exchange to
give 6. In order to generate 6 (Fe/L/OBz = 1:1:1), the mono-
and bidentate (OBz)– coligands in 5 [Fe/L/OBz = 3:2:(4+1)]
have to be substituted by the ditopic, tridentate ligand (L)–
(Scheme 2). Furthermore, these findings coherently explain
the irreversibility of the cyclic voltammograms of 4, 5, and
9.
Likewise, when the all-iron(iii) dimer [FeIII3O(L)2-
(OAc)4]2O (3) (Fe/L/OAc = 3:2:4) is cleaved with nickel ace-
tate in chloroform, the mixed-valent heteronuclear
[NiIIFeIII2O(L)3(OAc)3] (7) (M/L/OAc = 1:1:1) is formed.
Figure 1. Mössbauer spectrum of 5.
one ligand (L)– head-to-tail and Fe2/3 by one ligand (L)– This again is a complex reaction and requires the exchange
tail-to-head. Furthermore, Fe1/2 and Fe2/3 are linked by of FeIII-to-NiII and of (OAc)– coligand-to-(L)–. Since it was
one μ2-(OAc)– bridge, each, and Fe1/3 by two μ2-(OAc)– not possible to grow single crystals of acetate 7 suitable for
bridges. As a consequence, in the all-iron(iii) compound 4, X-ray structure determination, [NiIIFeIII2O(L)3(OBz)3] (8)
Fe1 and Fe3 are identically octahedrally coordinated. The was generated from 7 by exchange of the (OAc)– coligands
extra coordination site at Fe2 is occupied by a chloride ion, with (OBz)– ions (Scheme 2).
leading to charge compensation (Figure 2). As with 4, com-
plexes 2–10 were obtained as racemic mixtures.
The chelate complexes 6–8 are also accessible starting
from complex 2.[1] For example, 6 and 7 were prepared from
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Eur. J. Inorg. Chem. 2005, 1383–1387

Trinuclear Oxo-Centered Iron and Iron/Nickel Clusters
FULL PAPER
Figure 2. Molecular structure of 4 in the crystal (stereoview, PLUTON presentation, with the numbering of the iron ions, only one
stereoisomer shown). H atoms omitted for clarity. C: shaded; N: net; O: diagonal; S: mesh; Fe: void; Cl: cross. Selected bond lengths [Å]
and angles [°]: Fe1–μ3-O 1.87, Fe2–μ3-O 1.95; Fe1–μ3-O–Fe2 121.1, Fe1–μ3-O–Fe3 117.7.
ligand/coligand ratio M/L/co-L is 1:1:1, whereas, in homo-
valent 3–5 the ratio is 3:2:4. This result indicates ligand-
controlled stabilization of the all-FeIII and mixed-valent
species.
Experimental Section
General Methods: IR spectra were recorded from CHBr3 tritura-
tions with a Bruker IFS 25 spectrometer. FAB-MS spectra were
recorded with a Micromass ZAB-Spec spectrometer. Elemental
analyses were performed with an EA 1110 CHNS-Microautomat.
The microanalytical data for 4–9 deviate from theory due to vary-
ing crystal solvents and are not recorded here.
Materials: All reagents and solvents employed were commercially
available high-grade purity materials (Fluka, Aldrich), used as sup-
plied without further purification. Ligand HL (1) was prepared ac-
cording to ref.[2] Sodium 4-bromobenzoate was generated by reac-
tion of 4-bromobenzoic acid (1.1 equiv.) with NaH (1.0 equiv.) in
dry THF. The precipitate was filtered off, washed with THF and
dried in vacuo.
General Procedure: The metal salt (LiCl, NaOBz, Ni(OAc)2, NaI)
was added, in one portion, to a solution of complexes 3 or 5 in
chloroform. The initially pale violet suspension was stirred at 20 °C
Scheme 3. Synthesis of all-iron(iii) complex 9 and mixed-valent spe-
cies 10. In 10, the mixed valency is marked by segments.
for 48 h. After removal of the excess metal salt by filtration through
a pad of Celite, the remaining solution was concentrated to dryness.
mixed-valent homonuclear [FeIIFeIII2O(L)3(OAc)3] (2) by
Compound [FeIII3O(L)2(OAc)4]Cl (4): 3 (131 mg, 0.075 mmol), an-
mere exchange of the (OAc)– coligands by (OBz)– ions and
hydrous lithium chloride (509 mg, 12 mmol), and chloroform
(60 mL). Yield: 110 mg (81%) dark-violet crystals from CHCl3 by
by FeII-to-NiII exchange, respectively.
vapor diffusion of diethyl ether; m.p. Ͼ250 °C (decomp.). IR
(CHBr ): ν = 3137, 3109, 2995, 2923, 1615, 1575, 1556, 1505 cm–1.
˜
3
Conclusions
FAB-MS (m-NBA): m/z (%) = 902 (6) [M]+, 868 (100) [M – Cl]+,
809 (59) [M – Cl – OAc]+, 750 (22) [M – Cl – 2 OAc]+, 691 (11)
[M – Cl – 3 OAc]+, 644 (33) [M – Cl – L]+, 585 (32) [M – Cl –
OAc – L]+, 526 (25) [M – Cl – 2 OAc – L]+, 470 (21) [M – Cl – 2
OAc – L – Fe]+, 411 (21) [M – Cl – 3 OAc – L – Fe]+, 352 (16)
In summary, we have presented the cleavage of dimer 3
into 4, 5, and 7 and the interconversion of 5 into 6 and 7
into 8. Most interestingly, in mixed-valent homonuclear 2
and 6 and in mixed-valent heteronuclear 7 and 8 the metal/ [M – Cl – 4 OAc – L – Fe]+.
Eur. J. Inorg. Chem. 2005, 1383–1387
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R. W. Saalfrank et al.
FULL PAPER
Compound [FeIII3O(L)2(OBz)4]OBz (5): 3 (175 mg, 0.1 mmol), so-
dium benzoate (2.30 g, 16 mmol), and chloroform (80 mL). Yield:
178 mg (72%) dark-violet microcrystalline solid from CHCl3 by
vapor diffusion of diethyl ether; m.p. Ͼ250 °C (decomp.). IR
months with occasional opening). We suspect that aging of
Fe(OAc)2 leads to the formation of oligonuclear iron species.
This assumption is supported by the fact that reaction of ten-
membered iron wheel [FeIII10(OAc)10(OMe)20] with HL (1)
yields a mixture of [FeIIFeIII2O(L)3(OAc)3] (2), and [FeIII3O-
(L)2(OAc)4]2O (3, main product). The FeII ions in 2 are gener-
ated by reduction of FeIII by methanol. We generated
[FeIII10(OAc)10(OMe)20] in Ն80% yield simply by stirring
Fe(OAc)2 or FeCl2 together with NaOAc in air at 20 °C in
methanol for 10 h. The X-ray crystallographic data matched
those reported in ref.[10]
(CHBr ): ν = 3127, 3111, 2922, 1615, 1596, 1557, 1539, 1504 cm–1.
˜
3
FAB-MS (m-NBA): m/z (%)
=
1237 (3) [M]+, 1116 (91)
[M – OBz]+, 1013 (32) [M – L]+, 995 (100) [M – 2 OBz]+, 892
(60) [M – OBz – L]+, 874 (41) [M – 3 OBz]+, 771 (73) [M – 2 OBz –
L]+, 650 (76) [M – 3 OBz – L]+, 529 (35) [M – 4 OBz – L]+.
Compound [FeIIFeIII2O(L)3(OBz)3] (6): 5 (247 mg, 0.2 mmol), 1
(45 mg, 0.2 mmol), sodium iodide (50 mg, 0.33 mmol), and chloro-
form (50 mL). Yield: 129 mg (53%) dark-violet crystals from
CHCl3 by vapor diffusion of diethyl ether. For analytical data see
ref.[1]
Compound [NiIIFeIII2O(L)3(OAc)3] (7): 3 (123 mg, 0.07 mmol),
nickel acetate tetrahydrate (174 mg, 0.7 mmol), and chloroform
(30 mL). Yield: 68 mg (47%) brown precipitate from CHCl3/n-pen-
tane (5 mL/30 mL; once repeated). For analytical data see ref.[1]
Compound [NiIIFeIII2O(L)3(OBz)3] (8): 7 (52 mg, 0.05 mmol), so-
dium benzoate (432 mg, 3 mmol), and chloroform (10 mL). Yield:
42 mg (68%) brown crystals from CHCl3 by vapor diffusion of di-
ethyl ether. For analytical data see ref.[1]
Compounds [FeIII3O(L)2(OBzBr)4]OBzBr (9), [FeIIFeIII2O(L)3-
(OBzBr)3] (10): A suspension of iron(ii) acetate (348 mg, 2 mmol)
and sodium 4-bromobenzoate (6.70 g, 30 mmol) in chloroform
(300 mL) was stirred under nitrogen for 2 h. After addition of HL
(1) (534 mg, 2.4 mmol), the pale violet reaction mixture was stirred
in air for a further 48 h. After removal of the excess metal salt by
filtration through a pad of Celite, and concentration to dryness, the
mixture of 9 and 10 (ratio of ca. 6:1) was purified by fractionizing
crystallization from CH2Cl2/ether, yielding dark-violet crystals of
[4]
For further iron acetate complexes, see: a) C. T. Dziobkowski,
J. T. Wrobleski, D. B. Brown, Inorg. Chem. 1981, 20, 671–678;
b) C. J. Harding, R. K. Henderson, A. K. Powell, Angew.
Chem. 1993, 105, 583–585, Angew. Chem. Int. Ed. 1993, 32,
570–572; c) C. A. Christmas, H.-L. Tsai, L. Pardi, J. M. Kessel-
man, P. K. Gantzel, R. K. Chadha, D. Gatteschi, D. F. Harvey,
D. N. Hendrickson, J. Am. Chem. Soc. 1993, 115, 12483–12490;
d) I. Shweky, L. E. Pence, G. C. Papaefthymiou, R. Sessoli,
J. W. Yun, A. Bino, S. J. Lippard, J. Am. Chem. Soc. 1997, 119,
1037–1042; e) S. J. Lippard, Angew. Chem. 1988, 100, 353–371;
Angew. Chem. Int. Ed. Engl. 1988, 27, 344–361.
[FeIII3O(L)2(OAc)4]Cl
(4):
[5]
Crystal
data
for
C24H24ClFe3N6O11S4·3CHCl3·(C2H5)2O, M = 1335.96; crystal
dimensions 0.30×0.10×0.10 mm; monoclinic, space group C2/
c, a = 17.961(4) Å, b = 15.158(3) Å, c = 19.875(4) Å, β =
99.57(3)°, V = 5336(2) Å3; Z = 4; F(000) = 1828, ρcalcd.
=
1.663 g/cm3; Nonius KappaCCD diffractometer, Mo-Kα radia-
tion (λ = 0.71073 Å); T = 173(2) K; graphite monochromator;
θ range 2.30° Ͻ θ Ͻ 27.47°; section of the reciprocal lattice:
–23 Յ h Յ 23, –18 Յ k Յ 19, –25 Յ l Յ 25; of 11363 measured
reflections, 6097 were independent and 4434 with I Ͼ 2σ(I);
linear absorption coefficient 1.053 mm–1. The structure was
solved by direct methods using SHELXS-97 and refinement
with all data (309 parameters) by full-matrix least squares on
F2 using SHELXL97; all non-hydrogen atoms were refined an-
isotropically; R1 = 0.0541 for I Ͼ 2σ(I) and wR2 = 0.1651 (all
data); largest peak (0.748 eÅ–3) and hole (–1.226 eÅ–3).[6,7]
9. Yield: 348 mg (32%); m.p. Ͼ250 °C (decomp.). IR (CHBr ): ν =
˜
3
3107, 2920, 1589, 1554, 1504, 1411 cm–1. FAB-MS (m-NBA): m/z
(%) = 1656 (2) [M + Na]+, 1431 (80) [M – OBzBr]+, 1408 (14) [M –
L]+, 1232 (100) [M – 2 OBzBr]+, 1207 (39) [M – L – OBzBr]+, 1032
(51) [M – 3 OBzBr]+, 1008 (49) [M – L – 2 OBzBr]+, 831 (23) [M –
4 OBzBr]+, 808 (63) [M – L – 3 OBzBr]+, 752 (24) [M – Fe – L –
3 OBzBr]+. Complex 10 was characterized by FAB-MS and was
not further purified: FAB-MS (m-NBA): m/z (%) = 1458 (65)
[M + H]+, 1256 (100) [M – OBzBr]+, 1058 (31) [M – OBzBr]+.
[6]
[7]
a) G. M. Sheldrick, C. Krüger, P. Goddard, Crystallographic
Computing 3, Oxford University Press, Oxford 1985, p. 175; b)
G. M. Sheldrick, SHELXL-97, Program for Crystal Structure
Refinement, University of Göttingen 1997.
CCDC-213507 (4), -250374 (9), and -213506 [FeIII3O(L)3-
[9]
(OBz)3]I3 contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
[FeIII3O(L)2(OBzBr)4]OBzBr
(9):
[8]
Crystal
data
for
Acknowledgments
C51H32Br5Fe3N6O13S4·2.5CH2Cl2, M = 1844.48; crystal dimen-
sions 0.25×0.20×0.20 mm; monoclinic, space group P21/c, a
This work was supported by the Deutsche Forschungsgemeinschaft
SA 276/26-1, SFB 583, GK 312, SPP 1137, the Bayerisches Lang-
zeitprogramm “Neue Werkstoffe” and the Fonds der Chemischen
Industrie. The generous allocation of X-ray facilities by Professor
D. Sellmann, Institut für Anorganische Chemie, Universität Er-
langen-Nürnberg, cyclovoltammetric measurements by Professor J.
Daub and Dr. Ch. Trieflinger, Institut für Organische Chemie, Uni-
versität, Regensburg, and Mössbauer measurements by Dipl.-Phys.
L. Böttger, Institut für Physik der Medizinischen Universität
Lübeck, are also gratefully acknowledged.
=
19.506(4) Å,
b
=
16.882(3) Å,
c
=
21.112(4) Å,
β
=
=
105.74(3)°, V = 6691(2) Å3; Z = 4; F(000)= 3624, ρcalcd.
1.831 g/cm3; Nonius KappaCCD diffractometer, Mo-Kα radia-
tion (λ = 0.71073 Å); T = 173(2) K; graphite monochromator;
θ range 2.89° Ͻ θ Ͻ 25.05°; section of the reciprocal lattice:
–23 Յ h Յ 23, –18 Յ k Յ 20, –25 Յ l Յ 25; of 21421 measured
reflections, 11780 were independent and 8118 with I Ͼ 2σ(I);
linear absorption coefficient 4.015 mm–1. The structure was
solved by direct methods using SHELXS-97 and refinement
with all data (842 parameters) by full-matrix least squares on
F2 using SHELXL97; all non-hydrogen atoms were refined an-
isotropically; R1 = 0.0983 for I Ͼ 2σ(I) and wR2 = 0.2856 (all
data); largest peak (2.954 eÅ–3) and hole (–1.966 eÅ–3).[6,7]
[1] R. W. Saalfrank, A. Scheurer, U. Reimann, F. Hampel, C. Trie-
flinger, M. Büschel, J. Daub, A. X. Trautwein, V. Schünemann,
V. Coropceanu, Chem. Eur. J., submitted.
[2] R. W. Saalfrank, U. Reimann, M. Göritz, F. Hampel, A.
Scheurer, F. W. Heinemann, M. Büschel, J. Daub, V. Schüne-
mann, A. X. Trautwein, Chem. Eur. J. 2002, 8, 3614–3619.
[3] Fresh Fe(OAc)2 (Supplier Aldrich 51,793-3; 99.995%); aged
Fe(OAc)2 (kept under nitrogen in a Schlenk tube for 6–9
[9]
When 5 was treated with a fortyfold excess of sodium iodide
in the presence of air after workup some crystals of all-iron(iii)
complex [FeIII3O(L)3(OBz)3]I3 were isolated.[7] Crystal data for
[FeIII3O(L)3(OBz)3]I3: C45H33Fe3I3N9O10S6·3CHCl3,
M
=
1958.52; crystal dimensions 0.38×0.15×0.06 mm; triclinic,
space group P1, a = 14.2184(3) Å, b = 16.2989(3) Å, c =
16.6062(5) Å, α = 97.223(2)°, β = 106.855(2)°, γ = 110.318(2)°,
¯
1386
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Eur. J. Inorg. Chem. 2005, 1383–1387

Trinuclear Oxo-Centered Iron and Iron/Nickel Clusters
FULL PAPER
V = 3342.2(2) Å3; Z = 2; F(000)= 1906, ρcalcd. = 1.946 g/cm3;
Nonius KappaCCD diffractometer, Mo-Kα radiation (λ =
0.71073 Å); T = 100(2) K; graphite monochromator; θ range
3.31° Ͻ θ Ͻ 27.00°; section of the reciprocal lattice: –18 Յ h
Յ 18, –20 Յ k Յ 20, –21 Յ l Յ 21; of 61686 measured reflec-
tions, 14561 were independent and 9683 with I Ͼ 2σ(I); linear
absorption coefficient 2.635 mm–1. A numerical absorption
correction has been performed[11] (Tmin = 0.744, Tmax = 0.916).
The structure was solved by direct methods and refined with
all data (822 parameters) by full-matrix least squares on F2
using SHELXLTL NT 5.10.[12] With the exception of C301
(representing the minor component of a disordered CHCl3
solvate molecule) all non-hydrogen atoms were refined aniso-
tropically; R1 = 0.0574 for I Ͼ 2σ(I) and wR2 = 0.1613 (all
data); largest peak (2.653 eÅ–3) and hole (–2.052 eÅ–3).[6,7] All
significant residual electron density maxima can be found in
close proximity of either the I3 anion positions or the disor-
dered solvate molecule.
[10] C. Benelli, S. Parsons, G. A. Solan, R. E. P. Winpenny, Angew.
Chem. 1996, 108, 1967–1970; Angew. Chem. Int. Ed. Engl. 1996,
35, 1825–1828.
[11] P. Coppens, Crystallographic Computing, Munksgaard, Copen-
hagen, 1970, p. 255.
[12] SHELXTL NT 5.10, Bruker AXS, Inc., Madison WI, USA,
1998.
Received: September 30, 2004
Eur. J. Inorg. Chem. 2005, 1383–1387
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