Synthesis and structures of vinamidine MnII, ZnII, and CdII iodine derivatives

Article abstract of DOI:10.1002/1099-0682(200106)2001:6<1613::AID-EJIC1613>3.0.CO;2-Z

We have focused on the synthesis of monomeric, functionalized starting materials containing manganese(II), zinc(II), and cadmium(II) by taking advantage of the sterically demanding and chelating property of the substituted vinamidine ligand 2-[(2,6-diisopropylphenyl)amino]-4-[(2,6-diisopropylphenyl)imino]pent-2-ene (NacNacH). Metal iodine derivatives containing vinamidines as the bulky ligand can be regarded as interesting precursors for preparing complexes with low-valent metal centers by reduction as long as they are free of coordinated ether. The vinamidine complexes NacNacM(μ-I)₂Li(OEt₂)₂ [M = Mn (3), Zn (4), Cd (5)] are obtained from the corresponding vinamidine lithium complex and MI₂ (M = Mn, Zn, Cd) in good yields. A crystal structure analysis of 3, 4, and 5 shows them to be isostructural. All three structures have the vinamidine backbone in a boat conformation with the tetrahedrally coordinated metal center at the prow and the opposing carbon atom at the stern.

Full text of DOI:10.1002/1099-0682(200106)2001:6<1613::AID-EJIC1613>3.0.CO;2-Z

FULL PAPER
Synthesis and Structures of Vinamidine MnII, ZnII, and CdII Iodine Derivatives
Jörg Prust,[a] Kerstin Most,[a] Ilka Müller,[a] Andreas Stasch,[a] Herbert W. Roesky,*[a] and
[a]
´
Isabel Uson
Dedicated to Professor Glen B. Deacon on the occasion of his 65th birthday
Keywords: Cadmium / Manganese / N ligands / Zinc
We have focused on the synthesis of monomeric, func-
tionalized starting materials containing manganese(II),
zinc(II), and cadmium(II) by taking advantage of the
sterically demanding and chelating property of the substi-
long as they are free of coordinated ether. The vinamidine
complexes NacNacM(µ-I)2Li(OEt2)2 [M = Mn (3), Zn (4), Cd
(5)] are obtained from the corresponding vinamidine lithium
complex and MI2 (M = Mn, Zn, Cd) in good yields. A crystal
tuted vinamidine ligand 2-[(2,6-diisopropylphenyl)amino]-4- structure analysis of 3, 4, and 5 shows them to be isostructu-
[(2,6-diisopropylphenyl)imino]pent-2-ene (NacNacH). Metal
iodine derivatives containing vinamidines as the bulky li-
ral. All three structures have the vinamidine backbone in a
boat conformation with the tetrahedrally coordinated metal
gand can be regarded as interesting precursors for preparing center at the prow and the opposing carbon atom at the stern.
complexes with low-valent metal centers by reduction as
Introduction
We have focused on the synthesis of NacNacMI (M ϭ
Mn, Zn, Cd) as monomeric, functionalized starting mat-
erials due to the sterically demanding and chelating proper-
ties of 1.
Vinamidines were first used in inorganic synthesis by
Holm et al. and McGeachin et al. to synthesize moisture-
stable NiII, CoII, and CuII complexes.[1] In further research
the surprising catalytic activity of vinamidine derivatives of
various transition and main group metals was analyzed.
Feldman et al. synthesized catalytically active aryl-substi-
tuted vinamidine complexes of PdII and NiII, and Theopold
et al. and Gibson et al. tested vinamidine complexes of
TiIII, VII, CrIII for olefin polymerization.[2,3]
In the last few years the interest in the synthesis of mono-
meric and coordinatively unsaturated metal complexes with
bulky vinamidine ligands has increased. In this research
field several new compounds have been reported.[4] The vin-
amidine 2-[(2,6-diisopropylphenyl)amino]-4-[(2,6-diisopro-
pylphenyl)imino]pent-2-ene (1) (NacNacH) is suitable for
the synthesis of derivatives with unusually low coordinate
main group elements. Recently we synthesized a monomeric
AlI compound using 1 as a stable carbene analogue, and
Gibson et al. have prepared a mono-alkylmagnesium com-
plex stabilized by 1.[5,6] Our research focused on the syn-
thesis of complexes with low coordinate Mn, Zn and Cd
atoms.
Results and Discussion
The reaction of MeLi with NacNacH (1) gives the pale
yellow compound NacNacLi·OEt2 (2) in good yield (Ͼ
95%). This ether-soluble lithium compound is a useful re-
agent for metathesis reactions with metal halides. Thus, the
reaction of 2 with MI2 affords the iodide complexes Nac-
NacM(µ-I)2Li(OEt2)2 (M ϭ Mn, Zn, Cd) in reasonable
yields (77Ϫ85%) (Scheme 1).
Preparing the iodine-containing metal complexes of 1 has
two functions: the size of the ligand should have a shielding
effect on the metal center and therefore the nucleophilic at-
tack should be minimized; these systems should also be in-
teresting precursors for the preparation of complexes with
low-valent metal atoms by reduction of the iodine com-
plexes using alkali metals.
Scheme 1
[a]
Institut für Anorganische Chemie der Universität Göttingen,
Tammannstrasse 4, 37077 Göttingen, Germany
Fax: (internat.) ϩ49-551/39-3373
E-mail: hroesky@gwdg.de
Unfortunately compounds 3, 4, and 5 are moisture sensit-
ive and give 1 as the primary hydrolysis product. H NMR
1
Eur. J. Inorg. Chem. 2001, 1613Ϫ1616
WILEY-VCH Verlag GmbH, 69451 Weinheim, 2001
1434Ϫ1948/01/0606Ϫ1613 $ 17.50ϩ.50/0
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´
J. Prust, K. Most, I. Müller, A. Stasch, H. W. Roesky, I. Uson
FULL PAPER
spectroscopic data and the elemental analysis of 4 and 5 are environment of the metal. Thus, deviation from planarity
˚
consistent with the solid state structures, whereas the mass increases with the metal radius. The metal is about 0.30 A
˚
˚
˚
spectra of 3, 4, and 5 show several fragments assignable to (3: 0.33 A, 4: 0.29 A, 5: 0.34 A) out of the plane defined by
the species free of LiI(Et2O)2.[7]
The X-ray structure analysis of 3, 4 (shown in Figure 1),
and 5 shows that these compounds are isostructural. The
crystallographic data are summarized in Table 1. Selected
bond lengths and angles for 3, 4, and 5 are given in Table 2.
Figure 2 shows a superposition of 3, 4, and 5. The only
differences between the three structures are those derived
from the different bond lengths in the coordination of the
various metals. Therefore, we discuss the overall structure.
The central structural element is a NacNacM(µ-I)2Li
unit. The vinamidine ligand NacNac acts as a chelating li-
gand through its two N atoms, forming a six-membered
ring with the metal. The central metal (3: Mn, 4: Zn, 5: Cd)
and the lithium cation are bridged by the two iodine atoms.
The NϪMϪN-angle is about 95° (3: 94.2°, 4: 98.6°, 5:
91.5°) and the IϪMϪI-angle is 101° (3:101°, 4:101°,
5:101°). The tetrahedral coordination of the metal is dis-
torted due to the strain imposed by the six-membered ring
of the chelate, and the four-membered ring of the bridging
halides.
The MϪNϪC(CH3)ϪCHϪC(CH3)ϪN unit is not
planar. The six-membered ring displays a boat conforma-
tion with the metal at the prow and C(2) at the stern. This
deviation from planarity is imposed by the metal, as the
planar situation implies more distortion in the tetrahedral clarity); selected bond lengths [A] and angles [°] are given in Table 2
Figure 1. Molecular structure of 4 (hydrogen atoms are omitted for
˚
Table 1. Crystallographic data for 3, 4 and 5
3
4
5
Empirical formula
Molecular weight
Temperature [K]
C37H61I2LiMnN2O2
881.56
133(2)
C37H61I2LiN2O2Zn
891.99
133(2)
C37H61CdLiI2N2O2
939.02
133(2)
˚
Wavelength [A]
0.71073
0.71073
0.71073
Crystal system
Space group
Unit cell dimensions [A]
triclinic
P1
triclinic
P1
triclinic
P1
¯
¯
¯
˚
a ϭ9.773(2)
b ϭ 10.413(2)
c ϭ 20.699(4)
α ϭ 86.39(3)°
β ϭ 85.01(3)°
γ ϭ 78.89(3)°
2056.9(7)
a ϭ 9.6715(19)
b ϭ 10.374(2)
c ϭ 20.688(4)
α ϭ 86.17(3) °
β ϭ 84.64(3) °
γ ϭ 78.50(3) °
2022.7(7)
a ϭ 9.780(2)
b ϭ 10.410(2)
c ϭ 20.658(4)
α ϭ 86.70(3)°
β ϭ 85.19(3)°
γ ϭ 79.86(3)°
2060.9(7)
3
˚
Volume [A ]
Z
2
2
2
Density (calcd.) [Mg/m3]
Absorption coefficient [mmϪ1
F(000)
1.423
1.852
894
1.465
2.164
904
1.513
2.058
940
]
Crystal size [mm3]
θ range for data collection
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I Ͼ 2σ(I)]
0.30 ϫ 0.30 ϫ 0.20
1.98 to 26.34°
55863
8319 [Rint ϭ0.0495]
8319/69/429
1.161
R1 ϭ 0.0461
wR2 ϭ 0.1180
R1 ϭ 0.0524
wR2 ϭ 0.1217
1.718 and Ϫ1.615
0.40 ϫ 0.40 ϫ 0.30
2.01 to 23.25°
27007
5766 [Rint ϭ0.0531]
5766/69/431
1.144
R1 ϭ 0.0363
wR2 ϭ 0.0911
R1 ϭ 0.0403
wR2 ϭ 0.0941
1.175 and Ϫ1.013
0.40 ϫ 0.30 ϫ 0.20
1.98 to 26.37°
59137
8429[Rint ϭ0.0417]
8429/69/431
1.152
R1 ϭ 0.0308
wR2 ϭ 0.0728
R1 ϭ 0.0339
wR2 ϭ 0.0741
1.408 and Ϫ1.031
R indices (all data)
Largest diff. peak and hole
Ϫ3
˚
[e·A
]
1614
Eur. J. Inorg. Chem. 2001, 1613Ϫ1616

Synthesis and Structures of Vinamidine MnII, ZnII, and CdII Iodine Derivatives
FULL PAPER
˚
Table 2. Comparison of bond length [A] and angles [°] of 3, 4, 5
3 (M ϭ Mn)
4 (M ϭ Zn)
5 (M ϭ Cd)
MϪN(1)
MϪN(2)
MϪI(2)
MϪI(1)
I(1)Li(1)
I(2)ϪLi(1)
N(1)ϪC(1)
N(1)ϪC(11)
N(2)ϪC(3)
N(2)ϪC(21)
C(1)ϪC(2)
C(1)ϪC(10)
C(2)ϪC(3)
C(3)ϪC(30)
Li(1)ϪO(1)
Li(1)ϪO(2)
2.067(4)
2.090(4)
2.7230(9)
2.7354(9)
2.817(8)
2.920(9)
1.347(5)
1.447(5)
1.336(5)
1.445(5)
1.411(6)
1.511(6)
1.407(6)
1.523(6)
1.912(10)
1.982(10)
1.984 (3)
1.991(4)
2.6142(8)
2.6648(8)
2.784(8)
2.919(8)
1.318(6)
1.453(6)
1.332(6)
1.436(6)
1.399(6)
1.515(6)
1.398(6)
1.520(6)
1.930(9)
1.956(9)
2.188(2)
2.196(2)
2.7518(7)
2.7920(7)
2.816(6)
2.975(6)
1.322(4)
1.440(4)
1.332(4)
1.439(3)
1.407(4)
1.519(4)
1.410(4)
1.512(4)
1.899(6)
1.962(6)
N(1)ϪMϪN(2)
N(1)ϪMϪI(2)
N(2)ϪMϪI(2)
N(1)ϪMϪI(1)
N(2)ϪMϪI(1)
I(2)ϪMϪI(1)
MϪI(1)ϪLi(1)
MϪI(2)ϪLi(1)
C(1)ϪN(1)ϪM
C(3)ϪN(2)ϪM
N(1)ϪC(1)ϪC(2)
C(3)ϪC(2)ϪC(1)
N(2)ϪC(3)ϪC(2)
O(1)ϪLi(1)ϪO(2)
O(1)ϪLi(1)ϪI(1)
O(2)ϪLi(1)ϪI(1)
O(1)ϪLi(1)ϪI(2)
O(2)ϪLi(1)ϪI(2)
I(1)ϪLi(1)ϪI(2)
94.38(14)
119.67(10)
117.28(10)
113.04(10)
112.05(11)
101.07(4)
82.13(18)
80.45(16)
120.3(3)
120.3(3)
124.5(4)
131.1(4)
124.4(4)
114.9(5)
118.4(4)
102.9(4)
93.1(3)
98.78(15)
118.13(11)
116.92(11)
111.76(11)
110.38(11)
101.22(3)
83.38(17)
81.67(16)
118.8(3)
117.9(3)
124.6(4)
130.4(4)
124.9(4)
114.2(4)
118.3(4)
105.5(3)
93.2(3)
91.46(9)
121.77(7)
116.92(7)
113.31(7)
112.92(7)
101.13(3)
82.10(12)
79.95(12)
120.13(19)
120.23(19)
125.7(3)
132.7(3)
124.9(3)
116.2(3)
117.6(2)
102.7(2)
92.1(2)
Figure 2. Comparison of the molecular structures of 3, 4, and 5.
(organic substituents have been omitted for clarity)
(Et2O)2 is always found coordinated to the metal centers.
Moreover, the reduction of iodides with sodium or potas-
sium was also not successful. Consequently further research
is directed toward the synthesis of metal complexes free of
LiI(Et2O)2 using hydrocarbons as solvent.
133.1(4)
94.5(3)
133.8(4)
91.3(2)
132.6(3)
95.33(15)
Experimental Section
N(1)ϪC(1)C(10)ϪC(3)C(30)ϪN(2) and C(2) is about 0.19
General: All reactions were performed using standard Schlenk and
dry box techniques. Solvents were appropriately dried and distilled
under dinitrogen prior to use. All NMR spectra were obtained in
5 mm tubes using dry degassed [D6]benzene as a solvent, referenced
to external SiMe4. Elemental analyses were performed by the Ana-
lytisch-Chemisches Laboratorium des Instituts für Anorganische
Chemie, Göttingen.
˚
˚
˚
˚
A (3: 0.18 A, 4: 0.19 A, 5: 0.19 A) out of this plane.
Nevertheless, the π-electrons of the vinamidine are deloc-
alized since the C(1)ϪC(2) and the C(2)ϪC(3) as well as
the C(1)ϪN(1) and the C(3)ϪN(2) bond lengths are equal
within the experimental error and correspond to CϪC and
CϪN distances in aromatic systems. Both NϪM bond
lengths are equal.
Compound 1 was prepared according to the literature method.[3]
Although the bond lengths of the metal center to I(1)
Preparation of 2: MeLi (22.9 mL, 36.6 mmol, 1.6  in Et2O) was
added dropwise with a syringe over 10 min. to a stirred solution of
1 (15.3 g, 36.6 mmol) in Et2O (200 mL) at Ϫ78 °C. The mixture
was stirred at Ϫ78 °C for an additional 10 min. and allowed to
warm to room temperature, stirred overnight, and reduced in vol-
and I(2) are equal within the experimental error (3: 2.73/
˚
˚
˚
2.72 A, 4: 2.66/2.61A, 5: 2.79/2.75 A), the bond lengths of
˚
Li to I(1) and I(2) are significantly different (3: 2.81/2.92 A,
4: 2.78/2.92A, 5: 2.82/2.98 A). We suggest packing effects
˚
˚
to be responsible for these differences. The MϪIϪLiϪI ring ume to approximately 30 mL. Pale yellow solid 2 was isolated by
filtration, washed with pentane (3 ϫ 10 mL), and dried in vacuo.
(16.2 g, 89% yield). M.p.: 142Ϫ144 °C. Ϫ 1H NMR (400 MHz,
C6D6): δ ϭ 1.03 (t, J ϭ 6.8 Hz, 12 H, OCH2CH3), 1.19 [d, J ϭ
6.8 Hz, 12 H, CH(CH3)2], 1.22 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2],
1.93 (s, 6 H, CH3), 3.33 (q, J ϭ 6.8 Hz, 8 H, OCH2CH3), 3.40
[sept., J ϭ 6.8 Hz, 4 H, CH(CH3)2], 5.00 (s, 1 H, CH), 7.17 (m, 6
H, ArH). Ϫ 7Li NMR [155 MHz, C6D6, (LiCl/D2O)]: δ ϭ 1.61 (s).
Ϫ C33H51LiN2O (498.45): C 79.48, H 10.31, N 5.62; found C 80.26,
is not planar (dihedral angle, 3: 15.5°, 4: 17.7°, 5: 14.1°).
The coordination sphere of the Li cation is completed by
two diethyl ether molecules.
Conclusion
Unfortunately, the synthesis of low coordinate mono-
meric metal iodides has so far not been successful as LiI- H 10.21, N 5.63.
Eur. J. Inorg. Chem. 2001, 1613Ϫ1616
1615

´
J. Prust, K. Most, I. Müller, A. Stasch, H. W. Roesky, I. Uson
FULL PAPER
Preparation of 3: Compound 2 (2.50 g, 5.01 mmol) in Et2O (20 mL) The structures were solved by direct methods using SHELXS-97[10]
was added to a suspension of MnI2 (1.54 g, 5.01 mmol) in Et2O
(20 mL) at Ϫ78 °C. The reaction mixture was stirred at Ϫ78 °C for
an additional 10 min. and allowed to warm to room temperature.
After stirring the pink solution overnight the color changed to yel-
low. The yellow solution was filtered and the solvent removed un-
der reduced pressure to a volume of 10 mL. Yellow crystals were
obtained after 1 day at Ϫ24 °C. (3.75 g, 85% yield).[8] Ϫ MS (EI):
and refined against F2 on all data by full-matrix least-squares with
SHELXL-97.[11] All non-hydrogen atoms were refined aniso-
tropically. The hydrogen atoms were included in the model at geo-
metrically calculated positions and refined using a riding model.
The hydrogen atoms on C(10) in the structures of 4 and 5, however,
were refined as an idealized disordered methyl group with two half-
occupied positions related to one another by a rotation of 60°.
m/z (%) ϭ 202 (47) [DippNCCH3], 599 (100) [NacNacMnI]. Ϫ IR These hydrogen atoms were allowed to ride on the carbon atom
(Nujol): ν˜ ϭ 1655 (m), 1625 (m), 1262 (m), 1079 (s), 793 (s), 290 and rotate about the C(10)ϪC(1) bond. In all three structures the
(m) cmϪ1. Ϫ C37H61I2LiMnN2O2 (881.58): C 50.41, H 6.97, N 3.18; disordered methyl group of one of the diethyl ether molecules was
found C 50.43, H 6.89, N 3.23.[7]
modeled with the help of similarity restraints for 1Ϫ2 and 1Ϫ3
distances and displacement parameters. In all three structures there
are residual electron density maxima near the iodine atoms and
Li(1), presumably due to disorder which could not be modeled.
This unmodeled disorder could play a role in the apparently dis-
torted geometry at Li(1).
Preparation of 4: Compound 2 (1.26 g, 2.54 mmol) in Et2O (20 mL)
was added to a suspension of ZnI2 (811 mg, 2.54 mmol) in Et2O
(20 mL) at Ϫ78 °C. The reaction mixture was allowed to warm to
room temperature and stirred for an additional 24 h. The solution
was filtered and the solvent removed under reduced pressure to a
volume of 5 mL. Colorless crystals were obtained after 4 days at 2
Crystallographic data (excluding structure factors) for the struc-
tures included in this paper have been deposited with the Cam-
bridge Crystallographic Data Centre as supplementary publication
nos. CCDC 154416 (3), CCDC 154417 (4), CCDC 154418 (5). Cop-
ies of the data can be obtained free of charge on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax: (internat.)
ϩ 44-1223/336-033; Email: deposit@ccdc.cam.ac.uk].
1
°C. (1.79 g, 79% yield).[8] Ϫ H NMR (500 MHz, C6D6): δ ϭ 1.05
(t, J ϭ 6.8 Hz, 12 H, CH3CH2O), 1.14 [d, J ϭ 6.8 Hz, 12 H,
CH(CH3)2], 1.36 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.68 (s, 6 H,
CH3), 3.20 (t, J ϭ 6.8 Hz, 12 H, CH3CH2O), 3.51 [sept., J ϭ
6.8 Hz, 4 H, CH(CH3)2], 4.86 (s, 1 H, CH), 7.13 (m, 6 H, ArH). Ϫ
13C NMR (125 MHz, C6D6): δ ϭ 23.3 (s), 24.3 (s), 24.5 (s), 27.8
(s), 28.9 (s), 97.0 (s), 123.6 (s), 123.7 (s), 124.7 (s), 125.3 (s), 125.9
(s), 126.9 (s), 143.9 (s), 171.2 (s). Ϫ MS (EI): m/z (%) ϭ 202 (100)
[DippNCCH3], 608 (47) [NacNacZnI]. Ϫ IR (Nujol): ν˜ ϭ 1701 (m),
1615 (s), 1465 (m), 1412 (m), 1255 (s), 1054 (s), 763 (m), 243 (m)
cmϪ1. Ϫ C37H61I2LiN2O2Zn (892.03): C 49.82, H 6.89, N 3.14;
found C 49.60, H 6.61, N 3.59.
Acknowledgments
The financial support of the Deutsche Forschungsgemeinschaft
and Göttinger Akademie der Wissenschaften is gratefully acknow-
ledged.
Preparation of 5: Compound 2 (1.00 g, 2.01 mmol) in Et2O (20 mL)
was added to a suspension of CdI2 (733 mg, 2.01 mmol) in Et2O
(20 mL) at Ϫ78 °C. The reaction mixture was allowed to warm to
room temperature and stirred for an additional 36 h. After filtra-
tion from the residue the solvent was removed under reduced pres-
sure to a volume of 10 mL. Colorless crystals were obtained after
6 days at 2 °C. (1.45 g, 77% yield).[8] Ϫ 1H NMR (500 MHz, C6D6):
δ ϭ 1.02 (t, J ϭ 6.8 Hz, 12 H, CH3CH2O), 1.12 [d, J ϭ 6.8 Hz, 12
H, CH(CH3)2], 1.33 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.63 (s, 6 H,
CH3), 3.21 (t, J ϭ 6.8 Hz, 12 H, CH3CH2O), 3.44 [sept., J ϭ
6.8 Hz, 4 H, CH(CH3)2], 4.81 (s, 1 H, CH), 7.11 (m, 6 H, ArH). Ϫ
13C NMR (125 MHz, C6D6): δ ϭ 23.4 (s), 24.1 (s), 24.4 (s), 27.9
(s), 28.6 (s), 28.9 (s), 96.8 (s), 123.5 (s), 123.7 (s), 124.8 (s), 125.2
(s), 125.8 (s), 127.1 (s), 145.4 (s), 170.0 (s). Ϫ MS (EI): m/z (%) ϭ
202 (100) [DippNCCH3], 417 (52) [NacNac], 658 (58) [Nac-
NacCdI]. Ϫ IR (Nujol): ν˜ ϭ 1732 (m), 1440 (m), 1406 (s), 1268 (s),
1021 (m), 759 (s), 435 (m) cmϪ1. Ϫ C37H61CdI2LiN2O2 (939.05): C
47.32, H 6.55, N 2.98; found C 46.89, H 6.32, N 2.77.
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B. X. Qian, D. L. Ward, M. R. Smith, III, Organometallics
[4c]
1998, 17, 3070Ϫ3076. Ϫ
N. Kuhn, J. Fahl, S. Fuchs, M.
Steinmann, Z. Anorg. Allg. Chem. 1999, 625, 2108Ϫ2114.
C. Cui, H. W. Roesky, H.-G. Schmidt, M. Noltemeyer, H. Hao,
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[5]
[6]
[7]
[8]
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NMR spectroscopic data for 4 were not available due to the
paramagnetism of MnII.
According to the elemental analysis of a sample that was
treated at 180 °C an appreciable decomposition was already
observed at this temperature.
X-ray Crystallography: Crystals of 3 (mol. wt. 881.58), 4 (892.03),
and 5 (939.05) were grown from a concentrated Et2O solution
cooled to Ϫ24 °C (3) or 2 °C (4, 5). They crystallized in the triclinic
[9]
T. Kottke, D. Stalke, J. Appl. Crystallogr. 1993, 26, 615Ϫ619.
G. M. Sheldrick, SHELXS-90/96, Program for Structure Solu-
tion, Acta Crystallogr., Sect. A 1990, 46, 467Ϫ473.
G. M. Sheldrick, SHELXL-93/96, Program for Structure Re-
finement, Universität Göttingen, 1993.
¯
crystal system with space group P1. Relevant details and data stat-
[10]
istics are summarized in Table 1. The crystals were mounted on a
glass fiber in a rapidly cooled perfluoropolyether.[9] Diffraction
data were collected on a StoeϪSiemensϪHuber four-circle dif-
fractometer coupled to a Siemens CCD area detector at 133(2) K,
[11]
Received December 14, 2000
˚
with graphite-monochromated Mo-Kα radiation (λ ϭ 0.71073 A).
[I00472]
1616
Eur. J. Inorg. Chem. 2001, 1613Ϫ1616