Cyclopentadienyl/alkoxo ligand exchange in group 4 metallocenes: A convenient route to heterometallic species

Article abstract of DOI:10.1021/ic900498x

A simple and efficient strategy for the synthesis of nonorganometallic heterometallic clusters from cheap organometallic precursors Is reported. This unique synthetic method involves elimination of the cyclopentadienyl ring from Cp₂MCl₂

Full text of DOI:10.1021/ic900498x

6584 Inorg. Chem. 2009, 48, 6584–6593
DOI: 10.1021/ic900498x
Cyclopentadienyl/Alkoxo Ligand Exchange in Group 4 Metallocenes: A Convenient
Route to Heterometallic Species
,†
†
†
†
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‡
ꢀ
Piotr Sobota,* Anna Dra-g-Jarza-bek, yukasz John, Jozef Utko, Lucjan B. Jerzykiewicz, and Marek Duczmal
‡
†Faculty of Chemistry, University of Wroclaw, ul. F. Joliot-Curie 14, 50-383 Wroclaw, Poland, and Faculty of
e
e
·
ꢀ
Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
e
e
Received March 13, 2009
A simple and efficient strategy for the synthesis of nonorganometallic heterometallic clusters from cheap
organometallic precursors is reported. This unique synthetic method involves elimination of the cyclopentadienyl
ring from Cp2MCl2 (M = Ti, Zr, Hf) as CpH in the presence of M0L2 or M0L02 (M0 = Ca, Sr, Mn; CH3OCH2CH2OH = LH or
(CH3)2NCH2CH2OH = L0H) in an alcohol as a source of protons. In the reactions presented, a series of compounds,
[Ca4Ti2(μ6-O)(μ3,η2-L)8(η-L)2Cl4] (1), [Sr4Hf2(μ6-O)(μ3,η2-L)8(η-L)2(η-LH)4Cl4] (2), [Ca4Zr2(μ6-O)(μ-Cl)4(μ,η2-
L)8Cl2] (3), [Sr4Ti2(μ6-O)(μ3,η2-L)8(η-L)2(η-LH)2Cl4] (4), [Ca4Zr2Cp2(μ4-Cl)(μ-Cl)3(μ3,η2-L)4(μ,η2-L)4Cl2] (5),
[CaTiCl2(μ,η2-L0)3(η-L0H)3][L0] (6), [Ca2Ti(μ,η2-L0)6Cl2] (7), [Mn4Ti4(μ-Cl)2(μ3,η2-L)2(μ,η2-L)10Cl6] (8), and
[Mn10Zr10(μ4-O)10(μ3-O)4(μ3,η2-L)2(μ,η2-L)16(μ,η-L)4(η-L)2Cl8] (9), were obtained in good yield. All of the com-
plexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray structural
analysis. Complex 8 belongs to a group of magnetic clusters that consists of Mn4 subunits held together by two μ-Cl
bridges. Compounds 6 and 7 underwent thermal decomposition, yielding an alternative source for some heterometallic
oxides, which were analyzed by X-ray powder diffraction.
Introduction
Mehrotra and Singh,3c and Roesky et al.4 on the synthesis
and the catalytic properties of alkoxo heterometallic com-
plexes is notable. On the other hand, alkoxide complexes are
perfect candidates for sol-gel and metal-organic chemical
vapor-phase deposition conversion to corresponding oxide
products.5a,5b Furthermore, polymetallic clusters of para-
magnetic metal ions have attracted much study since the
discovery that such molecules can display single-molecule
magnetism (SMM).6 Only very few studies have been under-
taken to examine the magnetic properties of heterometallic
clusters, even though SMM will lead to an understanding of
quantum tunneling effects through synergy of metallic spins.7
These are crucial for today’s technology and are utilized
In the area of inorganic chemistry, there is widespread
interest in heterometallic complexes,especially those contain-
ing transition and main group metals.1 Such species possess
fascinating structural chemistry, interesting catalytic proper-
ties, and high potential for industrial applications.2 The
broad applicability of such compounds is a result of a
cooperation between two different metals in a single mole-
cule, which gives rise to properties that are not a simple sum
of the properties of the individual metals and is often crucial
for a system to achieve the desired activity. Thus, it is of
interest to develop a new synthetic strategy to incorporate
alkali metals into M-OR systems to generate compounds
containing the M0-O(R)-M unit (M=transition metals, M0=
main group metals). In this regard, the work of Bradley,3a,3b
(4) Chai, J.; Jancik, V.; Singh, S.; Zhu, H.; He, C.; Roesky, H. W.;
Schmidt, H.-G.; Noltemeyer, M.; Hosmane, N. S. J. Am. Chem. Soc. 2005,
*To whom correspondence should be addressed. Tel.: 048713757306. Fax:
048713282348. E-mail: plas@wchuwr.pl.
127, 7521–7528.
::
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(1) (a) Evans, W. J.; Ansari, M. A.; Ziller, J. W. Polyhedron 1997, 19,
3429-3434 and references therein. (b) Fischbach, A.; Herdtweck, E.;
Anwander, R.; Eickerling, G.; Scherer, W. Organometallics 2003, 22, 499-
509 and references therein. (c) Giesbrecht, G. R.; Gordon, J. C.; Brady, J. T.;
Clark, D. L.; Keogh, D. W.; Michalczyk, R.; Scott, B. L.; Watkin, J. G. Eur.
J. Inorg. Chem. 2002, 723–731.
(2) (a) Boffa, L. S.; Nowak, B. M. Chem. Rev. 2000, 100, 1479–1494.
(b) Angermund, K.; Fink, G.; Jensen, V. R.; Kleinschmidt, R. Chem. Rev.
2000, 100, 1457–1470. (c) Fink, G.; Steinmetz, B.; Zechlin, J.; Przybyla, C.;
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(c) Fernandez-Garcia, M.; Martinez-Arias, A.; Hanson, J. C.; Rodriguez,
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T. C.; Vittal, J. J. Inorg. Chem. 2006, 45, 8258–8263. (e) Labouthee, A.;
Wongkasemjit, S.; Traversa, E.; Laine, R. M. J. Eur. Ceram. Soc. 2000, 20,
91–97. (f) Mathur, S.; Veith, M.; Ruegamer, T.; Hemmer, E.; Shen, H.
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r
pubs.acs.org/IC
Published on Web 06/15/2009
2009 American Chemical Society

Article
Inorganic Chemistry, Vol. 48, No. 14, 2009 6585
for the production of superconductors, microelectronic
circuits, sensors, and ferroelectric materials and ceramic
materials.5c-5g In our research group, we have also synthe-
sized several structurally interesting heterometallic alkoxo-
organometallic compounds using reactions of metal alkox-
ides, which have a protonated hydroxyl group(s) in the
alcohol molecule present in the metal coordination sphere,
with organometallic compounds M0R3 (M0=Al, Ga, In; R=
Me, Et).8-10 These studies encouraged us to look for other
organometallic species as substrates for the synthesis of new
materials. Our studies on group 4 metallocenes showed that
Cp2MCl2 (M=Ti, Zr, Hf) areattractive and cheap precursors
to an extensive range of novel polymetallic molecular and
supramolecular materials.
toluene C6H5CH3 (30 mL). Stirring the dark-red solution
resulted in a slow change of color to blue and then to light
yellow over a period of 3 to 4 h. The mixture was vigorously
stirred at room temperature until all of the metal was consumed
(usually 4-5 h). After that time, the cloudy solution was filtered
off. The filtrate was reduced under vacuum conditions to a
powder. A total of 80 mL of hexanes were added, and the
mixture was stirred for about 30 min. The precipitate was
filtered off, washed with hexanes (3 ꢀ 15 mL), and dried to give
1 as a light-brown powder (1.82 g; 1.56 mmol, 72%). Colorless
crystals of 1 were grown by layering hexanes over a toluene
solution of 1. Anal. calcd for C30H70O21Cl4Ti2Ca4 (MW,
1164.78): C, 30.94; H, 6.06; Cl,12.18; Ca,13.76; Ti, 8.22. Found:
C, 30.74; H, 6.02; Cl,12.23; Ca,13.69; Ti, 8.24. IR (cm-1, Nujol
mull): 1820(w), 1640 (w), 1460 (vs), 1377 (s), 1278 (w), 1242 (m),
1200 (m), 1113 (vs), 1060 (vs), 1019 (s), 966 (w), 908 (s), 837 (s),
720 (m), 676 (s), 585 (s), 460 (s), 422 (m), 386 (m), 318 (vw),
253 (vw), 242 (w). 1H NMR (CDCl3, 298 K): δ 4.35-4.32 (t, 2H
of CH2), 3.73 (s, 3H of CH3), 3.45-3.41 (t, 2H of CH2). GC/MS:
CpH (MW, 66), CpH dimer (traces), 1-methylcyclohexa-1,
4-diene (traces), cyclopentene (traces). Method B. Complex 1
was also obtained during reaction of Cp2TiCl2 and CaL2
(synthesis of calcium 2-methoxyethoxide was carried out ac-
cording to the literature procedure: Goel, S. C.; Matchett, M.
A.; Chiang, M. Y.; Buhro, W. E. J. Am. Chem. Soc. 1991, 113,
1844) using Cp2TiCl2 (0.85 g; 3.41 mmol), CaL2 (1.30 g; 6.82
mmol), 5 mL of LH (4.82 g; 63.00 mmol), and toluene C6H5CH3
(40 mL). A procedure analogous to that for method A gave
colorless block crystals of 1 after 48 h. Elemental analysis and
spectroscopic data confirmed that the obtained compound was
complex 1.
Experimental Section
General. All reactions and operations were performed under
an inert atmosphere of N2 using standard Schlenk techniques.
Reagents were purified by standard methods: toluene, distilled
from Na; CH2Cl2, distilled from P2O5; and hexanes, distilled
from Na. Calcium (turnings, 99%), strontium (granule, 99%),
manganese (powder, 99.99%), 2-methoxyethanol (anhydrous
liquid, 99.8%), and N,N-dimethylethanolamine (anhydrous,
99.5+%) were obtained from Aldrich and used without further
purification unless stated otherwise. Bis(cyclopentadienyl)tita-
nium dichloride (Cp2TiCl2, powder, 97%), bis(cyclopentadie-
nyl)zirconium dichloride dichloride (Cp2ZrCl2, powder, 98+
%), and bis(cyclopentadienyl)hafnium dichloride (Cp2HfCl2,
powder, 98%) were obtained from Aldrich and used without
further purification. Infrared spectra were recorded on a Perkin-
Elmer 180 spectrophotometer in Nujol mulls. Electronic ab-
sorption spectra in solution were recorded on a CARY-50 UV-
vis (Varian) spectrometer at a concentration of 5 ꢀ 10-2 M. The
solvent (2-methoxyethanol) used in absorption was of spectro-
scopic grade and used as purchased (Sigma-Aldrich). NMR
spectra were obtained on a BRUKER ESP 300E spectrometer.
Gas chromatography/mass spectrometry (GC/MS) analyses
were recorded on an HP 5890II (Hewlett-Packard) gas chroma-
tograph with a mass detector. Microanalyses were conducted
with an ARL Model 3410 + ICP spectrometer (Fisons Instru-
ments) and a VarioEL III CHNS (in-house). Magnetic suscept-
ibility studies of complex 8 were performed in a temperature
range from 1.8 to 300 K in a field of 500 mT, and magnetizations
of up to 5 T at 2.0 K were measured with a Quantum De-
sign SQUID magnetometer. Diamagnetic corrections (-995 ꢀ
10-6 emu mol-1) were calculated using Pascal’s constants. The
oxide products were characterized recording X-ray powder
diffraction (XRD) patterns with a DRON-1 diffractometer
using Cu KR radiation (λ = 1.5418 A) filtered with Ni. The
measurements were done for 2θ=10-90ꢀ with a 2θ step=0.1ꢀ.
[Ca4Ti2(μ6-O)(μ3,η2-L)8(η-L)2Cl4] (1). Method A. A Schlenk
flask was charged with Cp2TiCl2 (1.08 g; 4.34 mmol), metallic
Ca (0.69 g; 17.22 mmol), 30 mL of LH (28.92 g; 0.38 mol), and
[Sr4Hf2(μ6-O)(μ3,η2-L)8(η-L)2(η-LH)4Cl4] (2). The proce-
dure was the same as that described for 1 (method A or B) with
Cp2HfCl2 and metallic Sr or SrL2 instead of Cp2TiCl2 and
metallic Ca or CaL2. Yield: 1.66 g; 0.86 mmol; 64%. Colorless
block crystals of 2 were grown by layering hexanes over a
toluene solution of 2. Anal. calcd for C42H102O29Cl4Sr4Hf2
(MW, 1920.50): C, 26.27; H, 5.35; Cl, 7.38; Sr, 18.25. Found:
C, 26.48; H, 5.26; Cl, 7.33; Sr, 18.27. IR (cm-1, Nujol mull):
3410 (w), 2753 (w), 1637 (w), 1458 (vs), 1376 (s), 1280 (w),
1241 (m), 1200 (m), 1116 (vs), 1056 (vs), 1018 (s), 967 (w), 906 (s),
839 (s), 720 (m), 677 (s), 584 (s), 461 (s), 424 (m), 386 (m),
318 (vw), 252 (vw), 242 (w). 1H NMR (CDCl3, 298 K): δ 4.40 (br,
2H of CH2), 3.71 (s, 3H of CH3), 3.40 (br, 2H of CH2). 13C{1H}
NMR (CDCl3, 298 K): δ 76.00 (s, CH2), 68.32 (s, CH2),
60.74 (s, CH3). GC/MS: CpH (MW, 66), CpH dimer (traces),
1-methylcyclohexa-1,4-diene (traces), cyclopentene (traces).
[Ca4Zr2(μ6-O)(μ-Cl)4(μ,η2-L)8Cl2] 2CH2Cl2 (3 2CH2Cl2).
3
3
The procedure was the same as that described for 1 (method A
or B) with Cp2ZrCl2 instead of Cp2TiCl2. The filtrate was
reduced under vacuum conditions to a powder and then dis-
solved in CH2Cl2 (60 mL). The solution was reduced under
vacuum conditions to 20 mL. Colorless crystals of 3 2CH2Cl2
3
were obtained after several weeks (1.47 g; 1.09 mmol; 67%).
Anal. calcd for C26H60O17Cl10Zr2Ca4 (MW, 1342.00): C, 23.27;
H, 4.51; Cl, 26.42; Ca, 11.95; Zr, 13.59. Found: C, 22.98; H, 4.32;
Cl, 25.86; Ca, 11.60; Zr, 13.15. IR (cm-1, Nujol mull): 1460 (vs),
1376 (s), 1244 (m), 1198 (m), 1122 (vs), 1074 (vs), 1018 (s),
914 (m), 838 (m), 780 (vw), 722 (vw), 662 (m), 574 (s), 464 (s),
424 (m), 404 (m), 340 (s), 240 (m), 218 (m). 1H NMR (CDCl3,
298 K): δ 3.76-3.70 (m, 2H of CH2), 3.50 (s, 3H of CH3), 3.42-
3.37 (m, 2H of CH2). GC/MS: CpH (MW, 66), CpH dimer
(traces).
ꢀ
(8) (a) John, y.; Utko, J.; Szafert, S.; Jerzykiewicz, L. B.; Ke-pinski, L.;
Sobota, P. Chem. Mater. 2008, 20, 4231–4239. (b) Szafert, S.; John, y.;
Sobota, P. Dalton Trans. 2008, 6509–6520.
(9) (a) Utko, J.; Ejfler, J.; Szafert, S.; John, y.; Jerzykiewicz, L. B.; Sobota,
P. Inorg. Chem. 2006, 45, 5302–5306. (b) Jerzykiewicz, L. B.; Utko, J.;
Sobota, P. Organometallics 2006, 25, 4924–4926. (c) Utko, J.; Lizurek, A.;
Jerzykiewicz, L. B.; Sobota, P. Organometallics 2004, 23, 296–298. (d) Utko,
J.; Przybylak, S.; Jerzykiewicz, L. B.; Szafert, S.; Sobota, P. Chem. Eur. J.
2003, 9, 181–190. (e) Sobota, P. Coord. Chem. Rev. 2004, 248, 1047–1060.
(f) Sobota, P.; Utko, J.; Sztajnowska, K.; Ejfler, J.; Jerzykiewicz, L. B. Inorg.
Chem. 2000, 39, 235–239. (g) Utko, J.; Szafert, S.; Jerzykiewicz, L. B.;
Sobota, P. Inorg. Chem. 2005, 44, 5194–5196.
[Sr4Ti2(μ6-O)(μ3,η2-L)8(η-L)2(η-LH)2Cl4] (4). The proce-
dure was the same as that described for 1 (method A or B) with
metallic Sr or SrL2 instead Ca or CaL2. Yield: 1.66 g; 1.23 mmol;
69%. Colorless block crystals of 4 were grown by layer-
ing hexanes over a toluene solution of 4. Anal. calcd for
C36H86O25Cl4Sr4Ti2 (MW, 1507.13): C, 28.69; H, 5.75; Cl,
(10) Sobota, P.; Przybylak, K.; Utko, J.; Jerzykiewicz, L. B.;
Armando, J. L.; Pombeiro, A. J. B.; Faatima, M.; Guedes, C.; Szczegot,
K. Chem. Eur. J. 2001, 7, 951–958.

6586 Inorganic Chemistry, Vol. 48, No. 14, 2009
Sobota et al.
9.41; Sr, 23.26; Ti, 6.35. Found: C, 28.60; H, 5.66; Cl, 9.83;
Sr, 23.27; Ti, 6.24. IR (cm-1, Nujol mull): 3420 (w), 2720(w),
1636 (w), 1460 (vs), 1376 (s), 1282 (w), 1244 (m), 1196 (m),
1116 (vs), 1058 (vs), 1018 (s), 966 (w), 906 (s), 836 (s), 722 (m),
676 (s), 584 (s), 458 (s), 424 (m), 386 (m), 320 (vw), 252 (vw),
244 (w). 1H NMR (CDCl3, 298 K): δ 4.42 (br, 2H of CH2), 3.72
(s, 3H of CH3), 3.43 (br, 2H of CH2). 13C{1H} NMR (CDCl3,
298 K): δ 76.07 (s, CH2), 68.32 (s, CH2), 60.66 (s, CH3). GC/MS:
CpH (MW, 66), CpH dimer (traces), 1-methylcyclohexa-1,
4-diene (traces), cyclopentene (traces).
Scheme 1. Synthesis of 1-4
Scheme 2. Synthesis of 5
[Ca4Zr2Cp2(μ4-Cl)(μ-Cl)3(μ3,η2-L)4(μ,η2-L)4Cl2] 1.5CH2Cl2
3
(5 1.5CH2Cl2). A Schlenk flask was charged with Cp2ZrCl2
3
(2.06 g; 7.05 mmol), CaL2 (1.46 g; 9.23 mmol), 30 mL of LH
(28.92 g; 0.38 mol), 30 mL of C6H5CH3, and 40 mL of CH2Cl2.
During the reaction, a white precipitate settled out. The mixture
was stirred at room temperature for 12 h. After that time, the
solution was filtered off. The precipitate was dried and dissolved
in THF (60 mL) at 70 ꢀC. The clear solution was reduced under
Scheme 3. Synthesis of 6 and 7
vacuum conditions to 30 mL. Colorless crystals of 5 1.5CH2Cl2
3
were obtained after 96 h (3.00 g; 2.33 mmol; 66%). Anal. calcd for
C71H136O32Cl18Ca8Zr4 (MW, 2825.42): C, 30.18; H, 4.85; Cl,
22.59; Ca, 11.35; Zr, 12.91. Found: C, 29.90; H, 4.23; Cl, 21.83;
Ca, 11.24; Zr, 12.54. IR (cm-1, Nujol mull): 1831 (vw), 1457 (vs),
1377 (m), 1257 (w), 1242 (w), 1197 (m), 1097 (s), 1078 (s), 1061 (vs),
1014 (s), 960 (w), 893 (m), 841 (s), 760 (m), 597 (s), 499 (m),
435 (m), 429 (m), 418 (m), 305 (w), 277 (w), 254 (m). 1H NMR
(CDCl3, 298 K): δ 6.56-6.09 (m, 5H of Cp), 4.32-4.29 (t, 2H of
CH2), 3.70 (s, 3H of CH3), 3.47-3.43 (m, 2H of CH2). GC/MS:
CpH (MW, 66), CpH dimer (traces), 1-methylcyclohexa-1,4-diene
(traces), cyclopentene (traces).
(2.05 g; 2.82 mmol; 70%). The filtrate was reduced under
vacuum conditions to 20 mL; then hexane (20 mL) was added
and formed a layer over the toluene solution. Colorless crystals
of 7 were obtained after 24 h. Anal. calcd for C24H60N6O6Cl2-
TiCa2 (MW, 727.72): C, 39.61; H, 8.31; N, 11.55; Cl, 9.74; Ca,
11.02; Ti, 6.58. Found: C, 39.34; H, 8.77; N, 11.21; Cl, 9.86;
Ca, 10.61; Ti, 5.97. IR (cm-1, Nujol mull): 2924 (vs), 2775 (s),
2699 (m), 1422 (w), 1403 (vw), 1356 (s), 1278 (s), 1251 (m),
1185 (m), 1170 (w), 1082 (vs), 1066 (vs), 1036 (vs), 1027 (vs),
951 (vs), 889 (vs), 783 (s), 617 (w), 578 (vs), 500 (vs), 463 (vs),
[CaTiCl2(μ,η2-L0)3(η-L0H)3][L0] (6). Method A. A Schlenk
flask was charged with Cp2TiCl2 (0.9 g; 3.61 mmol), metallic Ca
(0.15 g; 3.74 mmol), 20.00 mL of L0H (17.80 g; 0.20 mol), and
toluene C6H5CH3 (40 mL). The mixture was stirred at 80 ꢀC for
2 h. After that time, all of the metal had been consumed. Stirring
the dark-red solution resulted in a slow change of color to blue
and then to light yellow. A light-brown precipitate settled out
during the reaction. The solution was filtered off, and the
precipitate was washed with toluene (2 ꢀ 15 mL) and hexane
(2ꢀ15 mL) and then dried to give 6 as a white powder (1.66 g;
2.13 mmol; 59%). The filtrate was reduced under vacuum
conditions to 20 mL; then hexane (10 mL) was added and
formed a layer over the toluene solution. Colorless crystals of
6 were grown after 24 h. Anal. calcd for C28H73N7O7Cl2CaTi
(MW, 778.80): C, 43.18; H, 9.45; N, 12.59; Cl, 9.10; Ca, 5.15; Ti,
6.15. Found: C, 41.12; H, 9.55; N, 11.99; Cl, 9.36; Ca, 5.28;
Ti, 6.11. IR (cm-1, Nujol mull): 3312 (m), 2944 (vs), 1653 (vw),
1268 (m), 1181 (m), 1165 (m), 1090 (s), 1034 (s), 952 (m), 784 (m),
625 (m), 604 (m), 503 (m), 455 (m), 369 (w), 329 (vw), 222(w). 1H
NMR (CDCl3, 298K): δ 4.06 (s, 1H of OH), 3.63 (s, 2H of CH2),
2.48 (s, 2H of CH2), 2.27 (s, 3H of CH3). GC/MS: CpH (MW,
66), CpH dimer (traces). Method B. Complex 6 was also
obtained during the reaction of Cp2TiCl2 and CaL02, using
Cp2TiCl2 (0.90 g; 3.61 mmol), CaL02 (0.78 g; 3.61 mmol),
5 mL of L0H (4.45 g; 50.00 mmol), and toluene C6H5CH3
(40 mL). A procedure analogous to that for method A gave
colorless crystals of 6 after 24 h. Elemental analysis and spec-
troscopic data confirmed that the obtained compound was
complex 6.
1
437 (vs), 395 (vs), 335 (s), 283 (vs) 207 (s). H NMR (CDCl3,
298 K): δ 3.59 (s, 2H of CH2), 2.44 (s, 2H of CH2), 2.25 (s, 3H of
CH3). GC/MS: CpH (MW, 66), CpH dimer (traces). Method B.
Complex 6 was also obtained during the reaction of Cp2TiCl2
and CaL02 using Cp2TiCl2 (1.00 g; 4.02 mmol), CaL02 (1.74 g;
8.04 mmol), 5 mL of L0H (4.45 g; 50.00 mmol), and toluene
C6H5CH3 (40 mL). An analogous procedure to method A gave
after 24 h colorless crystals of 7. Elemental analysis and spectro-
scopic data confirmed the nature of complex 7.
[Mn4Ti4(μ-Cl)2(μ3,η2-L)2(μ,η2-L)10Cl6] 2C6H5CH3 (8 2C6-
3
3
H5CH3). A Schlenk flask was charged with Cp2TiCl2 (1.29 g;
5.2 mmol), metallic Mn (1.32 g; 24 mmol; Ti : Mn = 1: 4.6),
30 mL of LH (28.92 g; 0.38 mol), and toluene C6H5CH3
(20 mL). The mixture was stirred at 80 ꢀC for 12 h. After that
time, the solution was filtered off. The filtrate was reduced
under vacuum conditions to 30 mL. Green column crystals of
8 2C6H5CH3 were obtained from the toluene solution after 96 h
(1.43 g; 0.80 mmol; 62%). Anal. calcd for C50H100O24Cl8Mn4-
Ti4 2C7H8 (MW, 1780.26): C, 33.73; H, 5.66; Cl, 15.93; Ti,
3
3
10.76; Mn, 12.34. Found: C, 33.60; H, 5.63; Cl, 15.83; Ti, 10.57;
Mn, 12.24. IR (cm-1, Nujol mull): 1828 (vw), 1460 (vs), 1376 (m),
1260 (w), 1240 (w), 1194 (m), 1096 (s), 1078 (s), 1056 (vs),
1016 (s), 964 (w), 894 (m), 836 (s), 762 (m), 596 (s), 500 (m),
432 (m), 428 (m), 420 (m), 304 (w), 276 (w), 252 (m). UV-Vis:
576 nm. GC/MS: CpH (MW, 66), CpH dimer (traces),
1-methylcyclohexa-1,4-diene (traces), cyclopentene (traces).
[Mn10Zr10(μ4-O)10(μ3-O)4(μ3,η2-L)2(μ,η2-L)16(μ,η-L)4(η-L)2-
Cl8] (9). A Schlenk flask was charged with Cp2ZrCl2 (3.02 g;
10.33 mmol), metallic Mn (1.50 g; 27.30 mmol), 50 mL of LH
(48.20 g; 0.63 mol), and toluene (30 mL). The mixture was stirred
at 80 ꢀC for 12 h. After that time, the solution was filtered off.
The filtrate was reduced under vacuum conditions to 30 mL.
Colorless crystals of 9 were obtained after 96 h (2.41 g; 0.64 mmol;
62%). Anal. calcd for C72H168O62Cl8Mn10Zr10 (MW, 3771.26): C,
22.93; H, 4.49; Cl, 7.52; Mn, 14.57; Zr, 24.19. Found: C, 22.13;
H, 4.17; Cl, 7.38; Mn, 14.06; Zr, 24.04. IR (cm-1, Nujol mull):
1727 (w), 1600 (vw), 1496 (m), 1277 (m), 1245 (m), 1200 (m),
1180 (vs), 1102 (vs), 1051 (vs), 1016 (vs), 914 (vs), 842 (s), 736 (vs),
[Ca2Ti(μ,η2-L0)6Cl2] (7). Method A. A Schlenk flask was
charged with Cp2TiCl2 (1.00 g; 4.02 mmol), metallic Ca (0.39 g;
9.73 mmol), 20 mL of L0H (17.80 g; 0.20 mol), and toluene
C6H5CH3 (20 mL). The mixture was stirred at 80 ꢀC for 10 h.
Stirring the dark-red solution resulted in a slow change of color
to blue and then to light yellow over a period of 2 to 3 h. A light-
brown precipitate settled out during the reaction. After that
time, all of the metal had been consumed, and the solution was
filtered off. The precipitate was washed with toluene (2 ꢀ 15 mL)
and hexane (2 ꢀ 15 mL), then dried to give 7 as a white powder

Article
Inorganic Chemistry, Vol. 48, No. 14, 2009 6587
1
Figure 1. H NMR CpH spectra as a plot of the CpH/Cp2TiCl2 ratio against time for the reaction of Cp2TiCl2 with CaL02 and L0H (1: 2: 6) in toluene-d8.
Scheme 4. Synthesis of 8 and 9
698 (vs), 625 (vs), 574 (s), 530 (m), 511 (m), 461 (w), 401 (vw),
339 (m), 258 (m), 241 (m). GC/MS: CpH (MW, 66), CpH dimer
(traces), 1-methylcyclohexa-1,4-diene (traces), cyclopentene (traces).
Scheme 5. The Chloride Dissociation Equilibrium of Cp2MCl2 in LH
Results and Discussion
Synthesis. Reaction of Cp2MCl2 (M=Ti, Zr, Hf) with
2 equiv of M0L2 (M0=Ca, Sr) and an excess of LH (LH=
2-methoxyethanol) in toluene at room temperature gave
the colorless cyclopentadienyl-free heterometallic com-
pounds [Ca4Ti2(μ6-O)(μ3,η2-L)8(η-L)2Cl4] (1), [Sr4Hf2(μ6-O)-
(μ3,η2-L)8(η-L)2(η-LH)4Cl4] (2), [Ca4Zr2(μ6-O)(μ-Cl)4(μ,η2-
L)8Cl2] (3), and [Sr4Ti2(μ6-O)(μ3,η2-L)8(η-L)2(η-LH)2Cl4] (4)
after 12 h in good yield (Scheme 1).
The mild reactivity of the cyclopentadienyl/alkoxo
ligand exchange makes it possible to isolate some of the
intermediates and sheds light on the reaction pathway.
When the reaction of Cp2ZrCl2 with CaL2 in the presence
of LH was carried out in toluene/CH2Cl2 for 6 h, the
intermediate [Ca4Zr2Cp2(μ4-Cl)(μ-Cl)3(μ3,η2-L)4(μ,η2-L)4Cl2]
(5) was isolated (Scheme 2). Methane dichloride was
added to decrease the solubility of the resulting products.
To simplify the reactions, metallic M0 can be added
instead of M0L2 directly to Cp2MCl2 in a toluene/LH
solution. In this case, M0L2 is formed in situ directly from
M0 and LH. Moreover, the reaction pathway and the
composition of the final products may be controlled by
means of the M0/Cp2MCl2 ratio and the kind of alcohol.
The reaction of Cp2TiCl2 with 1 or 2 equiv of CaL02 in N,
N-dimethylethanolamine (L0H) causes the formation
of the complexes [CaTiCl2(μ,η2-L0)3(η-L0)3][L0] (6) and
[Ca2Ti(μ,η2-L0)6Cl2] (7), respectively (Scheme 3).
reacts with an excess of metallic Mn in toluene/LH at
80 ꢀC, a green solution is formed, from which cyclopen-
tadienyl-free paramagnetic blue crystalline [Mn4Ti4-
(μ-Cl)2(μ3,η2-L)2(μ,η2-L)10Cl6] (8) precipitates. Further-
more, the addition of metallic manganese to Cp2ZrCl2 in
toluene/LH results in the formation of a Cp-free hetero-
metallic cluster with the formula [Mn10Zr10(μ4-O)10(μ3-
O)4(μ3,η2-L)2(μ,η2-L)16(μ,η-L)4(η-L)2Cl8](9)(Scheme4).
The excess of manganese, which accelerates the reaction,
is easily removed by filtration, and the complexes can be
crystallized out almost quantitatively from the filtrate.
The appearance of free cyclopentadiene during the
reaction of Cp2TiCl2 with CaL02 in toluene-d8/L0H was
monitored using the 1H NMR technique and recorded at
various time intervals, generally up to 12 h, with the
sample maintained at room temperature. The recorded
CpH spectra make it possible to plot the dependence of
CpH/Cp2TiCl2 as a function of time (Figure 1). For
Cp2TiCl2, the amount of loss of titanium-bound Cp was
calculated by integrating the liberated CpH at δ 6.42-
6.48 ppm (2H of CpH) resonances versus the remaining
metal-bound η5-Cp signals at δ 5.92-5.94 ppm. The half-
life of ring loss for the Cp2TiCl2/CaL02/L0H reaction is ca.
1.0 h, and the chemical shifts of the remaining rings
are shifted toward lower frequencies compared with
Cp2TiCl2 in toluene-d8 at δ 5.89 ppm and are not equiva-
lent (Scheme 5 and Figure S9, Supporting Information).
The conversion was complete within 8 h, as evidenced by
In the meantime, we were also interested in exploring
the reaction of group 4 metallocenes with manganese,
which has interesting magnetic properties. When Cp2TiCl2

6588 Inorganic Chemistry, Vol. 48, No. 14, 2009
Sobota et al.
Table 1. Crystallographic Data for 1-5 and 7-9
compound
1
2
3
4
empirical formula
M
cryst syst
space group
a (A)
b (A)
c (A)
R (deg)
β (deg)
C30H70Ca4Cl4O21Ti2
1164.78
triclinic
P1
10.716(4)
11.923(5)
12.384(5)
107.03(1)
115.23(1)
102.48(1)
1257.8(9)
1
C42H102Cl4Hf2O29Sr4
1920.50
triclinic
C26H60Ca4Cl10O17Zr2
1342.00
triclinic
C36H86Cl4O25Sr4Ti2
1507.13
monoclinic
P21/n
12.167(4)
12.635(4)
19.566(5)
90
94.15(2)
90
P1
P1
12.184(4)
12.833(4)
13.258(5)
64.54(3)
75.31(2)
66.39(3)
1706.7(10)
1
1.865
11.019(5)
11.808(5)
11.829(6)
104.15(4)
115.31(5)
92.92(4)
1327.8(13)
1
1.678
γ (deg)
V (A3)
3000.0(16)
2
1.668
Z
Dcalcd (mg/m3)
cryst size (mm3)
1.538
0.283ꢀ0.148ꢀ0.087
0.244ꢀ0.197ꢀ0.113
0.212ꢀ0.182ꢀ0.036
0.44ꢀ0.20ꢀ0.13
μ (mm-1
θ (deg)
reflns collected
)
1.007
2.86 to 28.00
18313
6.363
2.96 to 27.05
20203
1.338
2.93 to 26.09
10492
4.034
2.60 to 29.11
40705
unique reflns, R(int)
final R1, wR2 [I > 2σ(I)]
final R1, wR2 (all data)
goodness-of-fit (S)
6028, 0.0239
0.0269, 0.0718
0.0340, 0.0740
1.059
7477, 0.0374
0.0237, 0.0504
0.0307, 0.0534
1.053
5230, 0.0189
0.0281, 0.0742
0.0353, 0.0773
1.067
8011, 0.1082
0.0466, 0.0770
0.1053, 0.0938
0.964
compound
5
7
8
9
empirical formula
M
cryst syst
space group
a (A)
b (A)
c (A)
R (deg)
β (deg)
C71H136Ca8Cl18O32Zr4
2825.42
monoclinic
C2/c
31.259(7)
17.216(5)
23.455(6)
90
111.19(4)
90
C24H60Ca2Cl2N6O6Ti
727.74
tetragonal
P42/n
19.723(6)
19.723(6)
9.562(4)
90
90
90
C50H100Cl8Mn4O24Ti4
1780.26
triclinic
C72H168Cl8Mn10O62Zr10
3771.26
triclinic
P1
P1
10.700(5)
10.787(6)
18.960(6)
85.12(3)
74.68(3)
77.63(3)
2060.7(16)
1
1.435
14.285(4)
15.639(5)
17.235(6)
116.46(3)
94.63(2)
100.02(3)
3339(2)
1
1.867
γ (deg)
V (A3)
11769(5)
4
1.595
3720(2)
4
1.300
Z
Dcalcd (mg/m3)
cryst size (mm3)
0.132ꢀ0.082ꢀ0.074
0.212ꢀ0.193ꢀ0.082
0.212ꢀ0.101ꢀ0.092
0.211ꢀ0.182ꢀ0.112
μ (mm-1
)
1.167
2.73to 28.00
49331
0.691
2.92to 25.00
8658
1.279
2.91to 27.50
28065
1.894
2.65to 27.50
48332
θ (o)
reflns collected
unique reflns, R(int)
final R1, wR2 [I > 2σ(I)]
final R1, wR2 (all data)
goodness-of-fit (S)
14064, 0.1334
0.0581, 0.0894
0.1720, 0.1194
0.837
3252, 0.0612
0.0501, 0.1093
0.0999, 0.1266
1.089
9425, 0.0687
0.0390, 0.0745
0.0880, 0.0845
0.860
15322, 0.1086
0.0518, 0.0905
0.1280, 0.1091
0.852
1H NMR. Whether only one or both Cp ligands are
exchanged or whether both processes take place side by
side strongly depends upon the reactants involved, their
stoichiometric ratio, the nature of the alcohol, and to a
great extent the nature of the metals, M and M0. It is
worth noting that the half-life of ring loss for Cp2TiCl2 in
KNO3/D2O solution is 57.0 ( 0.9 h at 37 ꢀC.11 The
dissolution of titanocene dichloride in water produces a
low pH, in which the chloride ligands are replaced by H2O
and OH- ligands, and results in protonation and loss of
the Cp groups and the formation of insoluble Ti oxo
species. It was also discovered that the addition of NEt3 to
the ethanol solution of Cp2ZrCl2 accelerates the hydro-
lysis process and shifts the chloride dissociation equilibria
substantially to the right, and Zr(OEt)4 is formed in good
yield.12
On the basis of the facts discussed above, it is obvious
that, in the first step, Cp2MCl2 undergoes transformation
involving chloride loss and the coordination of LH to the
(11) Toney, J. H.; Marks, T. J. J. Am. Chem. Soc. 1985, 107, 947–953.
(12) Gray, D. R.; Brubaker, C. H. Jr. Inorg. Chem. 1971, 10, 2143–2146.
Figure 2. View of the octahedral cores in compounds 1-4.

Article
Inorganic Chemistry, Vol. 48, No. 14, 2009 6589
Figure 3. (a) Molecular structure of 5. Hydrogen atoms omitted for clarity. (b) μ4-Cl in a [Ca4Zr2(μ-Cl)3(μ3-Oalkoxo)4(μ-Oalkoxo)4] cage.
metal center, followed by partial or total replacement of
the Cp groups by LH, providing in return proton func-
tionalities necessary for CpH liberation (Scheme 5).13 In
the second step, M0L2 binds the Cl- ions, shifts the
chloride dissociation equilibria to the right, and acceler-
ates a multiple-step process that proceeds with intermo-
lecular elimination of CpH from the metal site and leads
to the formation of compounds 1-9. Compounds 1-9
were isolated as crystalline and thermally stable solids,
air- and moisture-sensitive, and soluble in toluene at
room temperature. In the IR spectra of 2, 4, and 6, a
broad absorption band near 3400 cm-1 is assigned to the
stretching frequency of the coordinated alcohol hydro-
xide group.
X-Ray Structural Analyses. Crystals of complexes 1-9
were investigated using the single-crystal X-ray technique
Figure 4. Drawing of 6. Crystal data: monoclinic, P21/n, a=13.285(5),
b=15.846(5), c=22.013(8) A, β=117.48ꢀ, T=100 K.
and nine-coordinated in 2, whereas the axial metal ions
are always six-coordinated. It was observed that, as
the metal coordination number increased, so did the
(Table 1). Selected structures of 1, 5, 7, 8, and 9 are shown
length of the (μ6-Ooxo) bond distances and the defor-
in Figures 2, 3, 5-7, whereas all of the structures and
structural fits of all compounds are depicted in the
Supporting Information. The crystal structures of 1, 2,
mation of the octahedral entities. In all of these struc-
tures, the cores are slightly compressed in the axial
direction with respect to the equatorial plane. Although
and 4 are based on hexanuclear entities of the gene-
the mechanism of μ6-O oxo ligand formation is unknown,
ral formula [M4M02(μ6-Ooxo)(μ3-Oalkoxide)8] (M=Ca, Sr;
M0 =Ti, Hf). The metallic units can be described in two
ways: first, as an octahedron with six metal centers and a
μ6-oxo encapsulated oxygen atom residing at the central
position and each of the triangular faces being capped by
a μ3-oxygen atom of the alkoxide group (Figure 2);
second, as a cube formed by the eight oxygen atoms of
the alkoxide groups, with metal ions protruding out of the
six faces of the cube and an oxo ion occupying the central
position (Figure 2). In contrast to 1, 2, and 4, compound 3
has a [Ca4Zr2(μ6-O)(μ2-Cl)4(μ2-Oalkoxo)8] octahedral
core in which each edge of the polyhedron is alternately
capped by μ2-Oalkoxde groups or μ2-Cl anions (Figure 2).
In all hexanuclear complexes, the central μ6-oxo ion lies
on an inversion center. The equatorial metal centers
are six-coordinated in 3, eight-coordinated in 1 and 4,
the most probable source of the O2- anion is adventitious
hydrolysis or alkene/ether elimination reactions.14 Fur-
thermore, it is well-known that titanoxanes containing
oxo-bridged linkages Ti-O-Ti, for example, in [Ti2-
(μ-O)Cl2(η2-guaiacolato)4] or [Ti4(μ-O)4Cl8(MeCN)8],
are formed in situ by controlled hydrolysis of titanium
species.10,15
The molecular structure of 5 showed a Ca4 calcium
center with two [Ca2ZrCp(μ,η2-L)4Cl3] units joined by
three μ-Cl bridging chloride atoms to form the
[Ca4Zr2Cp2(μ-Cl)3(μ3,η2-L)4(μ,η2-L)4Cl2]+ cation encap-
sulating the μ4-Cl chloride ion in the center of the array
(Figure 3). While a few examples of a μ4-Cl bridging
chloride ion on late metal complexes of Cu, Cd, Ag, and
(14) Turova, N. Yu.; Turevskaya, E. P.; Kessler, V. G.; Yanovsky, A. I.;
Struchkov, Y. T. J. Chem. Soc., Chem. Commun. 1993, 21.
(15) Willey, G. R.; Palin, J.; Drew, M. G. B. J. Chem. Soc., Dalton Trans.
1994, 1799-1804 and references therein.
(13) Sobota, P.; Utko, J.; John, y.; Jerzykiewicz, L. B.; Dra-g-Jarza-bek, A.
Inorg. Chem. 2008, 47, 7939–7941.

6590 Inorganic Chemistry, Vol. 48, No. 14, 2009
Sobota et al.
Figure 5. Molecular structure of 7. Hydrogen atoms omitted for clarity.
Figure 6. Molecular structure of 8. Hydrogen atoms omitted for clarity.
Hg have been reported,16 this is to the best of our knowl-
edge the first unique example of a chloride μ4-Cl ion
located in a Ca4 cage.
The titanium-manganese compound 8 was obtained
as blue crystals and characterized by X-ray structural
analysis. The structural investigation reveals a centro-
symmetric octanuclear dimer with an inversion center
located at the midpoint of the central Mn2Cl2 fragment. It
consists of two equivalent asymmetric [Mn2Ti2(μ-Cl)-
(μ3,η2-L)2(μ,η2-L)10Cl3] (8) moieties linked by two μ-Cl
bridges (Figure 6). Each Mn2Ti2 unit can be described as
two MnTi2 triangular faces held together by the μ3- and
μ2-oxygen atoms of the L ligands. The edges of each
triangular face consist of μ2-oxygen atoms. The intermo-
Compound 6 was obtained in crystalline form and
identified by elemental analysis, spectroscopic data, and
X-ray diffraction studies. Unfortunately, its structure
could not be determined completely due to low-quality
crystals. Nonetheless, the structure is clearly visible
and can be discussed. The dimeric [CaTiCl2(μ,η2-L0)3-
(η-L0H)3]+ cation is composed of Ca(η2-L0)2(η-L0H)Cl2
and Ti(η2-L0)(L0H)2 moieties bridged by two amino-alk-
oxide oxygen atoms of the calcium L0 ligands. The anion
consists of deprotonated amino alcohol. An overall view
of the molecule is presented in Figure 4. Complex 7 is
composed of two calcium and one titanium ion that all,
with terminal chloride atoms, lie in a straight line. The
central Ti atom is located on an inversion center, and its
coordination sphere consists of the six alkoxide atoms
of the L0 anions. The centrosymmetrically related term-
inal calcium atoms are seven-coordinated with N3O3Cl
donors (Figure 5).
lecular Ti Ti distance is 2.967(2) A, which is com-
3 3 3
parable with the Ti Ti distance in R-Ti metal (2.8956 A).17
3 3 3
The intermolecular Mn Ti distances range from 3.315(2)
to 3.707(2) A.
3 3 3
The zirconium-manganese structure of 9 consists of a
Zr10Mn10 core held together by oxo, alkoxo, and chloride
ligands with different coordination modes: μ3, μ4, μ3,η2,
μ,η2, μ,η, η, and μ (Figure 7). The whole complex can
be divided into two guest-host subunits. The external,
host unit (fuchsia) consists of 10 Mn2+ outer-perimeter
ions linked with zirconium atoms by Ooxo and Oalkoxo
The internal, guest zirconium moiety (yellow) is formed
.
::
(16) (a) Muller, J. F. K.; Neuburger, M.; Weber, H.-P. J. Am. Chem. Soc.
1999, 121, 12212–12213. (b) Liaw, B.-J.; Lobana, T. S.; Lin, Y.-W.; Wang,
J.-C.; Liu, C. W. Inorg. Chem. 2005, 44, 9921–9929. (c) Salta, J.; Zubieta, J.
Inorg. Chim. Acta 1996, 252, 435–438. (d) Yang, X.; Knobler, C. B.; Zheng,
Z.; Hawthorne, M. F. J. Am. Chem. Soc. 1994, 116, 7142–7159.
(17) Weast, R. C. Handbook of Chemistry and Physics, 57th ed.; CRC:
Cleveland, OH, 1976; pp F-216.

Article
Inorganic Chemistry, Vol. 48, No. 14, 2009 6591
Figure 7. (a) Structure of 9. Hydrogen atoms omitted for clarity. (b) Metal-oxygen core.
by two fused corner-shared Zr6O8 units, in which six
zirconium ions are arranged at the apexes of an octahe-
dron. The equatorial zirconium centers of fused octahe-
drons are in one plane. In contrast to the structures of
1, 2, and 4, complex 9 does not have a μ6-O encapsu-
lated oxygen atom inside the metallic core. Each fused
Zr6O8 unit is also linked to others by two μ-Oalkoxide
atoms, in such a way that adamantane skeletons can be
identified. The dodecanuclear zirconium core is sur-
rounded by 10 manganese ions, which are joined to the
metallic center by alkoxide and oxo oxygen atoms.
The outer manganese unit is also stabilized by bridg-
ing chloride ions. All zirconium centers are seven-
coordinated, whereas manganese ions are five- and six-
coordinated.
Scheme 6. Possible Mn-Ti Magnetic Interactions

6592 Inorganic Chemistry, Vol. 48, No. 14, 2009
Sobota et al.
Figure 8. Variationofχ-1 (diamonds)andμeff (triangles)perMnII4TiIII
octamer with the temperature. The solid lines represent the fit to the
Kambe model (see text for details).
4
Figure 9. Powder XRD patterns: (a) precursor 6 decomposedat1400 ꢀC
in an air atmosphere, (b) CaTiO3 (ICSD 16688).
Magnetic Properties of 8. The presented synthetic
strategy can easily be envisioned as a convenient route
to the synthesis of paramagnetic complexes which might
have potential as SMMs. There are a number of articles
and reviews that cover the broad range of [Mn]4 chemistry
from synthetic strategies to theoretical investigations.18
In contrast, fewer studies have been undertaken to ex-
amine the magnetic properties of heterometallic sys-
tems.19 The magnetic susceptibility of 8 (Figure 8)
shows Curie-Weiss behavior in the temperature range
160-300 K, with the Weiss constant Θ=-18.3 K and a
magnetic moment of 12.34 μB, which is almost equal to
the 12.33 μB (g = 2.00) value expected for an uncoup-
led MnII4TiIII4 core with local spins SMn=5/2 and STi=
1/2. The effective magnetic moment slowly decreases
from 12.0 μB at 300 K to a broad minimum of 11.6 μB
at 45 K. Below 45 K, the value increases and reaches a
maximum of 12.78 μB at 2.7 K, very close to the value
expected for two isolated MnII2TiIII2 clusters with a total
spin ST=4 (12.65 μB, g=2.00). The magnetostructural
correlation between the MnII-Cl-MnII bond angle and
the exchange constant JMn-Mn is well-established.20,21
Magnetic interactions usually have an antiferromagnetic
character, but there is a narrow angle interval (93-98ꢀ)
where the exchange is very weak or even ferromagnetic.
The Mn-Cl-Mn bond angle in complex 8 is 97.08(5)ꢀ,
and it is assumed that the Mn4Ti4 cluster may be treated
as a Mn2Ti2 dimer containing only weakly interacting
halves. The experimental data were fitted using the
Kambe vector coupling method.22 The exact symmetry
of the Mn2Ti2 cluster is low, but a reasonable simplifying
Figure 10. Powder XRD patterns: (a) precursor 7 decomposed at 1400 ꢀC
in an air atmosphere, (b) CaTiO3 (ICSD 16688), (c) CaO (ICSD 1922).
approximation is possible by neglecting Mn1 Mn2
(6.190(2) A) and taking equal Mn1 Ti1 (3.706(2) A) and
3 3 3
3 3 3
Mn1 Ti2 (3.631(2) A) as well as Mn2 Ti1 (3.315(2) A)
and Mn4 Ti3 (3.350(2) A) magnetic interactions
(Scheme 6).
3 3 3
3 3 3
3 3 3
The magnetization of complex 8 was calculated in a
magnetic field of 500 mT using the method described
by Belorizky.23 Least-squares fitting of the data gave
JTi-Ti=-27.7 cm-1, JTi-Mn=-5.2 cm-1, g=1.98, and
zJ0=0.017 cm-1. Temperature-independent paramagnet-
ism was set at 130ꢀ10-6 emu mole-1 for Ti(III) and 0 for
Mn(II) ions.24 No paramagnetic impurity was needed for
ꢀ
(18) Roubeau, O.; Clerac, R. Eur. J. Inorg. Chem. 2008, 28, 4325–4342.
P
(19) (a) Sokol, J. J.; Hee, A. G.; Long, J. R. J. Am. Chem. Soc. 2002, 124,
7656–7657. (b) Osa, S.; Kido, T.; Matsumoto, N.; Re, N.; Pochaba, A.;
the simulation. The agreement factor R = [(χT )exp
-
P
(χT )calcd]2/ [(χT )exp]2 was 8.7 ꢀ 10-5 (68 points). The
ꢀ
Mrozinski, J. J. Am. Chem. Soc. 2004, 126, 420–421. (c) Zaleski, C. M.;
ground state was found to be |ST, STi, SMnæ = |4, 1, 5æ
Depperman, E. C.; Kampf, J. W.; Kirk, M. L.; Pecoraro, V. L. Angew.
Chem., Int. Ed. 2004, 43, 3912–3914. (d) Mishra, A.; Wernsdorfer, W.;
Abboud, K. A.; Christou, G. J. Am. Chem. Soc. 2004, 126, 15648–15649.
(e) Choi, H. J.; Sokol, J. J.; Long, J. R. Inorg. Chem. 2004, 43, 1606–1608.
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Article
Inorganic Chemistry, Vol. 48, No. 14, 2009 6593
tization are described in detail in the Supporting Infor-
mation.
synthetic route may be of great interest to chemists involved
with high-spin clusters, and more generally molecular mag-
netism. Furthermore, the resulting compounds6 and 7 have a
fixed metal ratio typical for perovskite and spinel materials.
In the case of complex 7, the expected spinel was not for-
med. This may be due to the presence of chlorine atoms
in the compound.25 In the literature, there are some
known examples of heterobimetallic acetate chlorides,
for instance, [Zn7(OAc)10(μ-OH)6Cu5(dmae)4Cl4] (where
dmae = (N,N-dimethylamino)ethanolate), that have been
used in chemical vapor deposition deposition to give the
double-oxide Cu5Zn7O12.27 A very attractive feature of spe-
cies 1-9 is that the metal ions have terminal chloride liga-
nds for substitution reactions to prepare larger molecules
by a building-block approach. These findings provide a
good illustration of the capabilities of the new synthetic
method.
Thermal Decomposition of 6 and 7. The heterobimetallic
complexes 6 and 7 seem to be natural precursors for
ceramic materials. They already have metal ratios typical
for perovskite and spinel materials, respectively. These
compounds were subjected to preliminary tests and ther-
mally decomposed in atmospheric air. The resulting
materials were analyzed by powder XRD analysis. The
diffraction patterns were obtained for 6 and 7, both
thermolyzed at 1400 ꢀC. The XRD pattern for compound
6 is an exact match to those for CaTiO3 perovskite
(Figure 9), and the PXRD spectrum of complex 7 can
be assigned to a mixture of CaTiO3 and CaO, while the
decomposition pathway is typical of SSP-III,25 where
there are both double and mono-oxides (Figure 10).
Conclusions
Acknowledgment. The authors would like to thank the
Polish State Committee for Scientific Research Grants
N205 4036 33 and the Foundation for Polish Science
(START Programme for Young Scientists) for their
support of this research.
In summary, we have developed a simple and efficient
strategy for the synthesis of nonorganometallic, heterome-
tallic clusters from cheap organometallic precursors. We
believe that the new synthetic route will be easily generalized,
making other as yet unknown heteropolymetallic com-
pounds with other d- and f-block metallocenes accessible.
In that case, we are sure that proper selection of the starting
materials as well as reaction conditions can lead to the
preparation of interesting objects with single-molecule mag-
netic properties. Complex 8 belongs to a group of magnetic
clusters that consist of Mn4 subunits held together by two
μ-Cl bridges.26 Although 8 is not a SMM, we believe that the
Supporting Information Available: Full crystallographic data
and molecular structures of 1-9, 1H NMR spectra for reaction
of Cp2TiCl2 with CaL02 and L0H (molar ratio 1:2:6) in toluene-
d8, GC-MS data (CpH/Ti ratio versus time plot for Cp2TiCl2
reactions with metallic Ca and CaL2), and a powder XRD
spectrum for 9 decomposed at 950 ꢀC are provided. This
material is available free of charge via the Internet at http://
pubs.acs.org.
(25) Veith, M. J. Chem. Soc., Dalton Trans. 2002, 2405–2412.
(26) Yoo, J.; Wernsdorfer, W.; Yang, E.-C.; Nakano, M.; Rheingold, A.
L.; Hendrickson, D. N. Inorg. Chem. 2005, 44, 3377–3379.
(27) Hamid, M.; Tahir, A. A.; Mazhar, M.; Zeller, M.; Hunter, A. D.
Inorg. Chem. 2007, 46, 4120–4127.