Synthesis and Characterization of Five-Coordinate Gallium and Indium
Complexes Stabilized by Tridentate, Substituted Pyrrole Ligands
Pei-Cheng Kuo,
[a]Jui-Hsien Huang,*
[a]Chen-Hsiung Hung,
[a]Gene-Hsiang Lee,
[b]and
Shie-Ming Peng
[b]Keywords: Gallium / Indium / N ligands / Bridging ligands
Five-coordinate gallium and indium complexes stabilized by tridentate, substituted pyrrole ligands have been synthesized and characterized. The reaction of MCl3 with 1 equiv. of
Li[NC4H2(CH2NMe2)2-2,5] in diethyl ether affords
[{NC4H2(CH2NMe2)2-2,5}MCl2] [M = Ga (1), In (2)] in high
yield. Reaction of 1 with 2 equiv. of MeLi in diethyl ether at −78 °C followed by heating to reflux for 30 min affords the alkylated product [{NC4H2(CH2NMe2)2-2,5}GaMe2] (3).
Sim-Introduction
Lewis acids catalyze a wide range of reactions. The
react-ivity and selectreact-ivity of these reactions are often related to
the Lewis acid’s electronic and steric properties.
[1]Among
the Lewis acid catalysts derived from group-13 metals, those
of aluminum are well known for serving as catalysts in
or-ganic synthesis, and more recently for polymerization
reactions.
[2⫺4]The number of metal complexes reported,
however, declines upon descending the group from
alumi-num to indium. Indium-mediated organometallic reactions
have received considerable attention recently, due to their
tolerance of polar solvents, including water.
[5⫺11]Lewis
acidic indium complexes are dominated by a low
coordina-tion number at the metal center (three or four)
[12⫺14]but a
few complexes of higher coordination number (five and six)
have been reported.
[15⫺21]We have been interested in the chemistry of
group-13
[22⫺23]and early transition metal complexes
[24⫺25]stabil-ized by bi- or tridentate substituted pyrrole ligands.
[26⫺27]These complexes are Lewis acids with the potential to serve
as catalysts in organic synthesis or for the polymerization
of olefins. We report here the syntheses, intramolecular
re-arrangement, and X-ray crystal structures of Ga and In
complexes.
[a] Department of Chemistry, National Changhua University of
Education,
Changhua 50058, Taiwan E-mail: [email protected]
[b] Department of Chemistry and Instrumentation Center,
National Taiwan University, Taipei 10764, Taiwan
ilarly, the reaction of 2 with 2 equiv. of MeLi or nBuLi affords the dialkylated complexes 4 and 5, respectively. Complex 2 is a strong Lewis acid which readily absorbs H2O forming
[{[C4H2N(CH2NMe2)2-2,5]InCl2}2(µ-OH2)] (6). Complexes 3,
4, and 6 have been characterized by X-ray crystallography. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Results and Discussion
Synthesis and Characterization
Reaction of Li[NC
4H
2(CH
2NMe
2)
2-2,5] with MCl
3(M
⫽
Ga, In) in diethyl ether affords [{NC
4H
2(CH
2NMe
2)
2-2,5}MCl
2] [M
⫽ Ga (1), In (2)] in yields of 98 and 81%,
respectively (Scheme 1). However, suitable crystals of
com-plexes 1 and 2 could not be obtained. The
1H and
13C
NMR spectra of both 1 and 2 show the signals of one type
of CH
2and NMe
2units at δ
艐 3.6 and 2.5 ppm,
respect-ively, which are consistent with symmetrical structures.
Reaction of complex 1 with 2 equiv. of 1.6
methylli-thium in diethyl ether solution at
⫺78 °C followed by
heat-ing to reflux for 30 min afforded the dimethylgallium
com-plex [{NC
4H
2(CH
2NMe
2)
2-2,5}GaMe
2] (3) in 75% yield.
The
1H NMR spectrum of 3 shows signals of one set of
CH
2, NMe
2, and GaMe units at δ
⫽ 3.47, 2.29, and ⫺0.37
ppm, respectively.
Similarly, treatment of 2 with 2 equiv. of MeLi or nBuLi
in a diethyl ether solution at
⫺78 °C, allowing to warm to
room temperature, and then heating to reflux for 30 min
generated the pure dimethyl complex 4 and the dibutyl
complex 5 in yields of 61 and 65%, respectively. Complexes
3, 4, and 5 are thermally robust and show no decomposition
upon heating in toluene at 100
°C for over 12 h.
Complex 2 is very Lewis acidic and reacts readily with
moisture upon exposure to air. During recrystallization of
2 from a toluene solution at
⫺20 °C, the Schlenk flask was
occasionally opened to air resulting in the deposition
of the water-bridged complex [{[C
4H
2N(CH
2NMe
2)
2-2,5]-InCl
2}
2(µ-OH
2)] (6). The procedure was carried out several
times in both toluene and diethyl ether, and the same result
was obtained. Attempts to let 2 react with 0.5 equiv. of H
2O
Scheme 1
in either toluene or diethyl ether afforded a mixture, from
which only a small amount of 6 was isolated. Similarly,
dif-fusion of H
2O vapor into a toluene solution of 2 yielded
the same results. The
1H NMR spectrum of 6 in CD
2Cl
2Table 1. Selected bond lengths [A˚ ] and angles [°] for compounds 3, 4, and 6 3
Ga⫺N(2) 1.920(2) Ga⫺C(2) 1.953(2) Ga⫺C(1) 1.969(2) Ga⫺N(1) 2.307(2)
Ga⫺N(3) 2.736(2)
N(2)⫺Ga⫺C(2) 121.38(10) N(2)⫺Ga⫺C(1) 114.36(9) C(2)⫺Ga⫺C(1) 123.10(11) N(2)⫺Ga⫺N(1) 77.13(7) C(2)⫺Ga⫺N(1) 102.57(9) C(1)⫺Ga⫺N(1) 99.66(9) N(2)⫺Ga⫺N(3) 69.92(6) C(2)⫺Ga⫺N(3) 90.63(8) C(1)⫺Ga⫺N(3) 98.27(9) N(1)⫺Ga⫺N(3) 146.68(6)
4
In(1)⫺N(2) 2.108(5) In(1)⫺C(2) 2.173(6) In(1)⫺C(1) 2.187 (6) In(1)⫺N(1) 2.519(5)
In(1)⫺N(3) 2.681(6) In(2)⫺N(5) 2.117(5) In(2)⫺C(14) 2.087(7) In(2)⫺C(13) 2.161(6) In(2)⫺N(4) 2.516(6) In(2)⫺N(6) 2.670(6)
N(2)⫺In(1)⫺C(2) 113.1(2) N(2)⫺In(1)⫺C(1) 121.2(2) C(2)⫺In(1)⫺C(1) 124.6(3) N(2)⫺In(1)⫺N(1) 71.9(2) C(2)⫺In(1)⫺N(1) 105.4(2) C(1)⫺In(1)⫺N(1) 101.3(2) N(2)⫺In(1)⫺N(3) 69.5(2) C(2)⫺In(1)⫺N(3) 94.5(3) C(1)⫺In(1)⫺N(3) 94.0(2) N(1)⫺In(1)⫺N(3) 140.96(19) N(5)⫺In(2)⫺C(14) 112.7(3) N(5)⫺In(2)⫺C(13) 119.5(2) C(14)⫺In(2)⫺C(13) 127.0(3) N(5)⫺In(2)⫺N(4) 71.5(2) C(14)⫺In(2)⫺N(4) 106.1(3) C(13)⫺In(2)⫺N(4) 98.4(2) N(5)⫺In(2)⫺N(6) 68.5(2) C(14)⫺In(2)⫺N(6) 95.2(3) C(13)⫺In(2)⫺N(6) 95.6(2) N(4)⫺In(2)⫺N(6) 139.5(2) 6·C7H8
In(1)⫺O(1) 2.136(4) In(1)⫺N(2) 2.167(5) In(1)⫺N(1) 2.334(5) In(1)⫺Cl(1) 2.434(2)
In(1)⫺Cl(1) 2.519(2) In(2)⫺N(5) 2.146(5) In(2)⫺O(1) 2.175(4) In(2)⫺N(4) 2.366(5)
In(2)⫺Cl(3) 2.462(2) In(2)⫺Cl(4) 2.4750(14)
O(1)⫺In(1)⫺N(2) 97.5(2) O(1)⫺In(1)⫺N(1) 156.9(2) N(2)⫺In(1)⫺N(1) 78.7(2) O(1)⫺In(1)⫺Cl(1) 106.64(10) N(2)⫺In(1)⫺Cl(1) 102.8(1) N(1)⫺In(1)⫺Cl(1) 96.4(1) O(1)⫺In(1)⫺Cl(2) 84.7(1) N(2)⫺In(1)⫺Cl(2) 154.2(1) N(1)⫺In(1)⫺Cl(2) 89.2(1) Cl(1)⫺In(1)⫺Cl(2) 101.14(6) N(5)⫺In(2)⫺O(1) 96.9(2) N(5)⫺In(2)⫺N(4) 77.6(2) O(1)⫺In(2)⫺N(4) 161.3(2) N(5)⫺In(2)⫺Cl(3) 98.7(1) O(1)⫺In(2)⫺Cl(3) 98.2(1) N(4)⫺In(2)⫺Cl(3) 100.4(1) N(5)⫺In(2)⫺Cl(4) 163.8(1) O(1)⫺In(2)⫺Cl(4) 84.7(1) N(4)⫺In(2)⫺Cl(4) 95.8(1) Cl(3)⫺In(2)⫺Cl(4) 97.03(6) In(1)⫺O(1)⫺In(2) 108.6(2)
at room temperature indicates an asymmetric arrangement,
which is consistent with the X-ray crystal structure (vide
infra). Complex 6 gives rise to three methyl resonances for
the two NMe
2units at δ
⫽ 2.50, 2.59, and 2.84 ppm in the
ratio of 1:1:2. Four doublets for the two AB systems of the
CH
2N units were observed at δ
⫽ 3.16, 3.70, 4.56, and 4.72
ppm in the ratio of 1:1:1:1. Selective homonuclear
decoup-ling of the
1H NMR spectrum of 6 revealed that one AB
pattern of a CH
2N unit gives rise to the resonances at δ
⫽
3.16 and 4.56 ppm while the other unit can be attributed to
the resonances at δ
⫽ 3.70 and 4.72 ppm.
Solid-State Structures of Complexes 3, 4, and 6
Crystals of 3 suitable for X-ray structure determination
were obtained from a saturated diethyl ether solution stored
at
⫺20 °C. Crystals of 4 were obtained by sublimation from
a flask in the glove box under nitrogen. Details of the data
collections for 3 and 4 are summarized in Table 2 with
se-lected bond lengths and angles listed in Table 1. The
OR-TEP diagram of complex 3 is depicted in Figure 1. The
gal-lium atom is surrounded by two methyl groups and three
nitrogen
atoms
of
the
tridentate
pyrrolyl
ligand,
[NC
4H
2(CH
2NMe
2)
2-2,5], forming a distorted
trigonal-bi-pyramidal structure. The tridentate pyrrolyl ligand is
ar-ranged at the meridional positions, with the pyrrolyl
nitro-gen atom occupying the equatorial position and the two
NMe
2units occupying the axial positions. The axial
Figure 1. ORTEP diagram of complex 3; thermal ellipsoids at the 50% probability level and hydrogen atoms are omitted for clarity
by 33.32
° due to the geometrical constraints of the two
fused five-membered rings. It is noteworthy that the
N(1)
⫺Ga and N(3)⫺Ga bond distances of 2.307(2) and
2.736(2) A
˚ , respectively, are significantly different. The unit
cell of 4 contains two independent molecules and the
struc-ture of one of these is shown in Figure 2. The strucstruc-ture of
4 is very similar to that of complex 3. However, the
differ-ence of 0.14 A
˚ in the metal-to-axial-nitrogen bond lengths
In(1)
⫺N(1) [2.519(5) A˚] and In(1)⫺N(3) [2.661(6) A˚] is
smaller in 4 than in the corresponding gallium species. This
is consistent with the larger atomic radius of indium. The
axial angle, N(1)
⫺In⫺N(3) [140.96(19)°], deviates from
lin-earity by 39.04
° due to the steric constraints imposed by
the two fused five-membered rings.
Crystals of complex 6 were obtained by dissolving 2 in
toluene and cooling to
⫺20 °C. The reaction of 2 with
moisture was effected by slowly exposing the solution to air
occasionally. This caused crystals of 6 to appear in the
flask. The crystals were collected and characterized by
1H
NMR spectroscopy and a single-crystal X-ray diffraction
study. Details of the data collection for complex 6 are
sum-Figure 2. ORTEP diagram of complex 4; thermal ellipsoids are at the 50% probability level and hydrogen atoms are omitted for clarity
marized in Table 2 with selected bond lengths and angles
listed in Table 1. The ORTEP diagram of 6 is shown in
Fig-ure 3. The structFig-ure of 6 can be described as corner-sharing
bis(square-pyramidal), in which the oxygen atom acts as the
corner atom with Cl(1) and Cl(3) occupying the apical
posi-tions. A view of the coordination spheres of the two indium
centers is shown in Figure 4, where the two square planes
are joined by the oxygen atom. The In(1) and In(2) atoms
are
displaced
from
the
planes
defined
by
N(1)
⫺N(2)⫺O(1)⫺Cl(2) and N(4)⫺N(5)⫺O(1)⫺Cl(4) by
0.4717 and 0.3389 A
˚ , respectively. The question has been
raised as to whether the oxygen-containing bridging groups
should be viewed as water molecules or dianionic oxo
groups. Although the hydrogen atoms of the bridging group
were not found either in the
1H NMR spectrum or in the
X-ray crystal structure, three points support the water-bridged
formulation for the dinuclear indium complex: (1) In both
4 and 6, both pyrrolyl groups exist as σ-coordinated ligands
with similar In
⫺N distances [2.108(5) vs. 2.17 A˚].
Further-more, accommodation of the two methyl groups results in
an oxidation state of
⫹3 for the In center. These data
sug-gest that the oxygen atom is coordinated to the indium
Figure 3. ORTEP diagram of complex 6; thermal ellipsoids are at the 50% probability level and hydrogen atoms are omitted for clar-ity
Figure 4. View of the coordination spheres of complex 6 showing only atoms coordinated to the indium atom; thermal ellipsoids are at the 50% probability level
atom via a lone pair of electrons. (2) The bond angle
sub-tended by In(2)
⫺O(1)⫺In(1) in complex 6 is 108.6(2)°,
which is very close to the sp
3bonding angle of 109.28. (3)
Finally, an IR spectrum of 6 supports the existence of the
bridged H
2O molecule, since a broad characteristic OH
stretching peak was observed at 3460 cm
⫺1.
Oxygen-atom-bridged dinuclear indium complexes have been observed
often,
[28⫺30]however, water-bridged diindium complexes
have not been reported.
Experimental Section
General Procedures: All reactions were performed under dry nitro-gen using standard Schlenk techniques or a glove box. Toluene, diethyl ether, and tetrahydrofuran were dried by heating to reflux in the presence of sodium benzophenone ketyl. CH2Cl2was dried
with P2O5. All solvents were distilled and stored under nitrogen in
solvent reservoirs containing 4-A˚ molecular sieves. 1H and 13C
NMR spectra were recorded with a Bruker AC 200 spectrometer. Chemical shifts for1H and13C spectra were recorded in ppm
relat-ive to the residual protons of the solvent or the13C resonances of
the deuterated solvent: CDCl3(δ⫽ 7.24, 77.0 ppm), C6D6(δ⫽
7.15, 128.0 ppm), or CD2Cl2(δ⫽ 5.24, 54.0 ppm). Elemental
ana-lyses were performed with a Heraeus CHN-OS Rapid Elemental Analyzer at the Instrument Center, NCHU. [C4H3N(CH2NMe2)2
-2,5] and Li[C4H2N(CH2NMe2)2-2,5] were prepared according to
previously reported procedures.[23⫺25]InCl3(Strem) and MeLi
(Al-drich) were used as received.
[{C4H2N(CH2NMe2)2-2,5}GaCl2] (1): A 100-mL Schlenk flask was charged with a solution of GaCl3(5.0 g, 28.57 mmol) in diethyl
ether (30 mL). This solution was added dropwise to a suspension of Li[C4H2N(CH2NMe2)-2,5] (5.34 g, 28.57 mmol) in diethyl ether
(20 mL) with stirring at⫺78 °C. The mixture was allowed to warm to room temperature and stirred for 5 h. The resultant suspension was filtered through Celite. The filtrate was concentrated to dryness and the resultant solid was recrystallized from diethyl ether to af-ford 1 (9.0 g, 98%).1H NMR (CDCl 3): δ⫽ 2.52 (s, 12 H, NMe2), 3.63(s, 4 H, CH2N), 5.95 (s, 2 H) ppm.13C NMR (CDCl3): δ ⫽ 47.0 (q, JC,H⫽ 136 Hz, NMe2), 58.8 (t, JC,H⫽ 139 Hz, CH2N), 105.2 (d, JC,H⫽ 167 Hz), 128.0 (s) ppm. C10H18Cl2GaN3(320.90): calcd. C 37.43, H 5.65, N 13.09; found C 36.93, H 5.68, N 12.55. [{C4H2N(CH2NMe2)2-2,5}InCl2] (2): This complex was prepared in a similar way to that described for 1, starting from InCl3(3.0 g,
13.6 mmol) and Li[C4H2N(CH2NMe2)-2,5] (2.53 g, 13.6 mmol).
Yield: 4.03 g (81%).1H NMR (CDCl 3): δ⫽ 2.54 (s, 12 H, NMe2), 3.65 (s, 4 H, CH2N), 5.99 (s, 2 H) ppm.13C NMR (CDCl3): δ⫽ 46.5 (q, JC,H⫽ 137 Hz, NMe2), 59.3 (t, JC,H⫽ 138 Hz, CH2N), 106.4 (d, JC,H⫽ 167 Hz), 129.5 (s) ppm. C10H18Cl2InN3(365.99): calcd. C 32.82, H 4.96, N 11.48; found C 32.26, H 4.54, N 10.92. [{C4H2N(CH2NMe2)2-2,5}GaMe2] (3): A 50-mL Schlenk flask was charged with diethyl ether (20 mL) and 1 (2.0 g, 6.23 mmol) and the resultant solution was cooled to⫺78 °C. To this solution was added MeLi (1.4 in diethyl ether, 4.45 mL, 12.5 mmol) via syr-inge. The mixture was stirred at room temperature for 5 h, and the resultant suspension was heated to reflux for 30 min and filtered through Celite. The filtrate was concentrated to dryness affording 3 in 75% yield (1.30 g).1H NMR (CDCl 3): δ⫽ ⫺0.37 (s, 6 H, GaMe), 2.29 (s, 12 H, NMe2), 3.48 (s, 4 H, CH2N), 5.89 (s, 2 H) ppm.13C NMR (CDCl 3): δ⫽ ⫺9.32 (q, JC,H⫽ 121 Hz), 45.9 (q, JC,H⫽ 137 Hz, NMe2), 58.9 (t, JC,H⫽ 136 Hz, CH2N), 103.0 (d, JC,H⫽ 163 Hz), 131.9 (s) ppm. C12H24GaN3 (280.06): calcd. C 51.46, H 8.64, N 15.00; found C 49.802, H 8.036, N 14.51. The error in the elemental analysis may be due to traces of LiBr in the final product.
[{C4H2N(CH2NMe2)2-2,5}InMe2] (4) and [{C4H2N(CH2NMe2)2 -2,5}InBu2] (5): A similar procedure described for the preparation of complexe 3 was applied for the preparation of 4 and 5. The yield of 4 was 61% (0.54 g, based on 1.0 g of 2).1H NMR (CDCl 3): δ⫽ ⫺0.31 (s, 6 H, InMe), 2.31 (s, 12 H, NMe2), 3.47 (s, 4 H, CH2N), 5.91 (s, 2 H) ppm. 13C NMR (CDCl 3): δ ⫽ ⫺10.6 (q, JC,H ⫽ 126 Hz), 46.1 (q, JC,H⫽ 135 Hz, NMe2), 59.4 (t, JC,H⫽ 135 Hz, CH2N), 103.0 (d, JC,H ⫽ 164 Hz), 131.9 (s) ppm. C12H24InN3 (325.16): calcd. C 44.33, H 7.44, N 12.92; found C 44.92, H 6.96, N 12.65. For 5 the yield was 65% (0.73 g, based on 1.0 g of 2) of a brown viscous liquid after removing all volatiles. Due to the vis-cosity of complex 5, it could not be purified by recrystalli-zation or distillation. 1H NMR (CDCl 3): δ ⫽ 0.66 (t, 4 H, InCH2CH2CH2CH3), 0.89 (t, 6 H, InCH2CH2CH2CH3), 1.31 (m, 4 H, InCH2CH2CH2CH3), 1.57 (m, 4 H, InCH2CH2CH2CH3), 2.34 (s, 12 H, NMe2), 3.45 (s, 4 H, CH2N), 5.91 (s, 2 H) ppm.13C NMR (CDCl3): δ⫽ 13.2 (t, JC,H⫽ 140 Hz), 13.7 (q, JC,H⫽ 123 Hz), 28.8 (t, JC,H⫽ 125 Hz), 30.3 (t, JC,H⫽ 128 Hz), 46.8 (q, JC,H⫽ 137 Hz, NMe2), 60.0 (t, JC,H⫽ 135 Hz, CH2N), 103.0 (d, JC,H⫽
164 Hz), 132.7 (s). No elemental analysis was performed due to a small amount of impurity present in the product.
[{[C4H2N(CH2NMe2)2-2,5]InCl2}2(µ-OH2)] (6): The same proced-ure was applied for the preparation of 6 as that used to synthesize 2, with the exception that during recrystallization of complex 2 from a toluene solution at⫺20 °C the Schlenk flask was periodic-ally opened to air. This resulted in the deposition of 6 on the bot-tom of the flask (1.03 g,13%, based on 5 g of InCl3).1H NMR
(CD2Cl2): δ ⫽ 2.50 (br. s, 6 H, NMe2), 2.59 (br. s, 6 H, NMe2), 2.84 (br. s, 12 H, NMe2), 3.16 (d, 4 H, CH2N), 3.70 (d, 4 H, CH2N), 4.56 (d, 4 H, CH2N), 4.72 (d, 4 H, CH2N), 6.01 (d, 2 H), 6.26 (d, 2 H) ppm. 13C NMR (CD 2Cl2): 47.8 (q, JC,H⫽ 136 Hz, NMe2), 49.6 (q, JC,H⫽ 135 Hz, NMe2), 50.2 (q, JC,H⫽ 135 Hz, NMe2), 60.6 (t, JC,H⫽ 139 Hz, CH2N), 61.3 (t, JC,H⫽ 145 Hz, CH2N), 106.3 (d, JC,H⫽ 167 Hz), 114.9 (d, JC,H⫽ 164 Hz), 122.5 (s), 136.0
(s). A small amount of complex 2 was present in 6 (less than 3% by
1H NMR spectroscopy), which prevented a reasonable elemental
analysis from being obtained.
X-ray Structure Determination of Complexes 3, 4, and 6: Crystals were mounted on a glass fiber using epoxy resin and transferred to the goniostat. Data collections were preformed at 150 K under li-quid nitrogen vapor for complexes 3 and 6 and at 293 K for com-plex 4. Data were collected with a Bruker SMART CCD diffracto-meter with graphite-monochromated Mo-Kαradiation. Structural
determinations were carried out using the SHELXTL package of programs. All refinements were carried out by the full-matrix least-squares method using anisotropic displacement parameters for all non-hydrogen atoms. All the hydrogen atoms were placed in calcu-lated positions. The crystal data are summarized in Table 2. CCDC-185057 and -185059 contain the supplementary crystallo-graphic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cam-bridge CB2 1EZ, UK; Fax: (internat.)⫹ 44-1223/336-033; E-mail: [email protected]].
Acknowledgments
We thank the National Science Council of Taiwan for financial support and the National Center for High Performance Computing
Table 2. Summary of crystallographic data for compounds 3, 4, and 6
3 4 6
Empirical formula C12H24GaN3 C24H48In2N6 C27H46Cl4In2N6O
Formula mass 280.06 650.32 842.14
Temperature [K] 150(1) 293(2) 150(1)
Crystal system orthorhombic monoclinic monoclinic
Space group Pbca C2/c P21/c
a [A˚ ] 12.1751(6) 27.4334(17) 9.3723(1) b [A˚ ] 15.2278(7) 9.1830(6) 17.6586(3) c [A˚ ] 15.6050(7) 27.5320(17) 21.9571(2) β [°] 90 117.23(1) 92.704(1) Volume [A˚3]/Z 2893.2(2)/8 6173.1(7)/8 3629.89(8)/4 Density (calcd.) [Mg/m3] 1.286 1.399 1.541 Absorption coefficient [mm⫺1] 1.884 1.514 1.594 F(000) 1184 2656 1696 Crystal size [mm] 0.50⫻ 0.40 ⫻ 0.10 0.36⫻ 0.31 ⫻ 0.07 0.20⫻ 0.10 ⫻ 0.10 θ range [°] 2.51 to 27.50 1.66 to 27.51 1.48 to 27.50
No. of reflns. collected 16753 19182 20140
No. of indep. reflns. 3318 (Rint⫽ 0.0375) 7066 (Rint⫽ 0.0339) 8096 (Rint⫽ 0.08533)
Max./min. trans. 0.6471/0.4120 0.9486/0.8740 0.8621/0.5674
No. of data/restraints/params. 3318/0/146 7066/0/297 8095/0/362
Goodness of fit on F2 1.094 1.014 1.017
Final R indices [I⬎ 2σ(I)], R1[a] 0.0363 0.0409 0.0581
wR2[b] 0.0754 0.0830 0.1007
R indices (all data), R1[a] 0.0463 0.1177 0.1045
wR2[b] 0.0793 0.1137 0.1169
Largest diff. peak/hole [e·A˚⫺3] 0.674/⫺0.615 0.765/⫺0.739 1.812/⫺1.210
[a]R
1⫽ Σ|Fo|⫺ |Fc|/Σ|Fo|.[b]wR2⫽ {Σ[w(Fo2⫺ Fc2)2]/Σ[w(Fo2)2]1/2}.
for databank searches. We also thank Dr. Darin Tiedtke for helpful discussions and for proofreading this manuscript.
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Received July 17, 2002 [I02392]
![Table 1. Selected bond lengths [A ˚ ] and angles [°] for compounds 3, 4, and 6 3](https://thumb-ap.123doks.com/thumbv2/9libinfo/8680250.197088/2.892.85.416.93.479/table-selected-bond-lengths-angles-compounds.webp)
