Trivalent cerium and praseodymium aromatic Ketone adducts

Article abstract of DOI:10.1002/ejic.201201171

The reactions of the aromatic ketones benzophenone and 9-fluorenone with trivalent [LnL₃] complexes [Ln = Ce, Pr; L = N(SiMe₃) ₂, C₅H₅ (Cp)] produce highly colored solutions in toluene. Characterizati

Full text of DOI:10.1002/ejic.201201171

FULL PAPER
DOI:10.1002/ejic.201201171
Trivalent Cerium and Praseodymium Aromatic Ketone
Adducts
Alan R. Crozier,[a] Karl W. Törnroos,[a] Cäcilia Maichle-Mössmer,[b]
and Reiner Anwander*[b]
Keywords: Cerium / Praseodymium / Cyclopentadienyl ligands / Ketones / Rare earths
The reactions of the aromatic ketones benzophenone and 9-
fluorenone with trivalent [LnL3] complexes [Ln = Ce, Pr; L =
N(SiMe3)2, C5H5 (Cp)] produce highly colored solutions in
toluene. Characterization of these complexes by X-ray dif-
fraction revealed them to be monoadducts of the form
[LnL3(ketone)]. The crystallographically determined C–O
bonds of these complexes are longer than those of the free
ketones. Significant ligand-to-metal charge transfer is also
indicated by the ν(C=O) vibration of the coordinated ketone,
which appears at lower wavelength. Solution-based 1H NMR
spectroscopy showed paramagnetic spectra of complexes
Ln[N(SiMe3)2]3(ketone) and Ln(C5H5)3(ketone), which fur-
ther supports this finding.
Introduction
The large, electropositive, and oxophilic nature of the
rare-earth metal(III) (LnIII) centers is considered responsi-
ble for the outcome of many organic transformations.[1]
Specifically, cerium complexes have been utilized as envi-
ronmentally friendly promoters in organic synthesis.[2] For
cerium complexes, reductive processes including the Luche
protocol[3] and carbon–carbon bond-forming reactions
such as the Grignard/CeCl3 system developed by Imam-
oto[4] and, for praseodymium, the EtPrI-catalyzed Tishch-
enko redox condensation[5] all involve an initial LnIII–carb-
onyl coordination step. Teuben et al. studied the carbon–
carbon bond-forming and -breaking reactions of the CeIII
-
promoted aldol reaction by use of the well-defined organol-
anthanide complex (C5Me5)2Ce[CH(SiMe3)2].[6] It was
found that its reactivity toward aliphatic ketones is domi-
nated by hydrogen transfer reactions (C–H bond activation/
deprotonation), which produce enolate/ketone complex A
and (C–C coupled) aldolate species (C5Me5)2Ce[OC-
Me2CH2C(=O)Me] (B), depending on the steric bulk of the
carbonylic substrate.
these reactions and shed light on some aspects of the some-
what unpredictable oxidation behavior of trivalent cerium
complexes.[7] The most remarkable CeIII/IV–ketone redox as-
sembly was reported by Sen et al. in 1992 and features the
hydroquinolato-bridged CeIV alkoxide complex C, which is
accessible by the oxidation of Ce(OtBu3)3 with p-benzo-
quinone.[8] Such distinct reactivity is in sharp contrast with
the known oxidatively inert, solution-based chemistry of
praseodymium complexes [E0(LnIII/IV) = +1.74 (Ce), +2.86
to +3.4 (Pr, estimated) V].[9] Herein, we describe the synthe-
sis and characterization of the benzophenone (Ph2CO) and
9-fluorenone (C13H8O) adducts of two common cerium and
praseodymium complexes, namely, tris(hexamethylsilyl-
amido)- and tris(cyclopentadienyl)cerium and -praseo-
dymium.
A detailed understanding of the LnIII–oxygen bond in
these systems can help rationalize the transition states of
[a] Department of Chemistry, University of Bergen,
Allégaten 41, 5007 Bergen, Norway
[b] Institut für Anorganische Chemie, Eberhard Karls Universität
Tübingen,
Auf der Morgenstelle 18, 72076 Tübingen, Germany
Fax: +49-7071-29-2436
E-mail: reiner.anwander@uni-tuebingen.de
Homepage: http://www.mnf.uni-tuebingen.de/fachbereiche/
chemie/institute/anorganische-chemie/institut/
ag-anwander.html
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201201171.
Results and Discussion
The addition of Ph2CO or C13H8O to toluene solutions
of yellow CeL3 [L = N(SiMe3)2, C5H5] produced the
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Scheme 1. Synthesis of compounds 1–4 by reaction of Ln[N(SiMe3)2]3 and LnCp3 with ketone in toluene (a: Ln = Ce; b: Ln = Pr; route a:
Ph2CO; route b: C13H8O).
monoaddition complexes Ce[N(SiMe3)2]3(Ph2CO) (1a), angles in the range 154.8(1)–172.2(1)°, and praseodymium
Ce[N(SiMe3)2]3(C13H8O) (2a), CeCp3(Ph2CO) (3a), and complex 4b shows the least deviation from linearity. No-
CeCp3(C13H8O) (4a). Green solutions of PrL3 gave the tably, the corresponding cerium complex 4a revealed a
analogous praseodymium adduct complexes 1b–4b. All re- much more acute Ce–O–C(carbonyl) bond angle of 154.7°.
actions proceeded instantaneously upon addition of the The C–O bond lengths of the donating ketones average
ketone and gave deeply colored yellow, red, or green solu- 1.235 Å and are all in good accordance with those of other
tions (Scheme 1).
lanthanide–ketoneadductcomplexessuchasTb[N(SiMe3)2]3-
Cooled toluene solutions of these compounds produced (Ph2CO),[10] DyCp3(Ph2CO),[11] and the urea complex
colored crystals suitable for X-ray crystallography. The 4- CeCp3(NMe2CO).[12] The rare-earth metal complexes
and 10-coordinate complexes of cerium (Figure 1) and [Y(OC14H11)2(OC14H11)]2(C13H8O),[13] YCp3(Ph2CO),[14]
praseodymium (Supporting Information, Figures S1–S4) and other X=OǞLn adducts[15] also compare well. The C–
show a datively bonded ketone unit. The Ln–O(carbonyl) and O bond lengths of the donor adduct complexes 1–4 are in
C=O bond lengths are shown in Table 1. The silylamide contrast with known lanthanide[16] and uranium[17] ketyl
complexes 1 and 2 adopt slightly distorted pyramidal geo- radical complexes, where this bond elongates to ca. 1.3 Å.
metries. The average N–Ln–N bond angles for both Ln = A selection of literature (X–O)–M bond lengths is shown in
Ce and Pr are ca. 113 and 118° for the Ph2CO and C13H8O Table 2. The retention of the trivalent state of the cerium
complexes, respectively. The cyclopentadienyl complexes 3 complexes was confirmed by the Ce–O(carbonyl) bond length,
and 4 exhibit Cp(centroid)–Ln–Cp(centroid) bond angles of ca. which is in good agreement with other CeIII–O[6,18] dis-
117°. The donating ketones display Ln–O–C(carbonyl) bond tances. As expected, the CeIII–ketone adducts display
Figure 1. Perspective ORTEP views of the molecular structures of 1a–4a (left to right) with 50% probability ellipsoids; hydrogen atoms
are omitted for clarity. ORTEP drawings of complexes 1b–4b can be found in the Supporting Information, Figures S1–S4.
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slightly longer Ce–O donor bonds (av. 2.476 Å) than the
Conclusions
corresponding praseodymium adducts (av. 2.461 Å).[19]
The commonly used trivalent hexamethylsilylamide and
cyclopentadienyl complexes of cerium and praseodymium
rapidly produce donor complexes with the aromatic ketones
benzophenone or 9-fluorenone. The cerium complexes re-
sist oxidation in the presence of these ketones, which are
capable of forming stable ketyls at ambient temperature.
Aromatic ketones remain unsuitable as oxidants despite the
known oxophilicity of trivalent cerium. Electron-with-
drawing fluorinated derivatives of the ketones used within
this study are currently under investigation as alternatives.
The reactions with the donor ketones produced intense
color changes, which gives an indication of significant
charge transfer; this is supported by the infrared spectro-
Table 1. Summary of selected bond lengths [Å] for 1–4.
Compound C–O(carbonyl) Ln–O(carbonyl)
Ln–L[a]
Ph2CO[20]
1.223(2)
–
–
–
–
C13H8O[21] 1.219(2)
1a
2a
3a
4a
1b
2b
3b
4b
1.242(2)
1.235(2)
1.234(5)
1.230(2)
1.244(2)
1.238(2)
1.234(3)
1.223(2)
2.475(1)
2.465(1)
2.481(3)
2.484(1)
2.4566(9)
2.4446(9)
2.472(2)
2.471(1)
2.358–2.367 (2.363)
2.345–2.375 (2.365)
2.549–2.565 (2.558)
2.545–2.561 (2.555)
2.341–2.347 (2.344)
2.329–2.356 (2.346)
2.528–2.542 (2.537)
2.511–2.544 (2.527)
[a] L = N (1, 2) and Cp(centroid) (3, 4), Ln–L average values in paren-
theses.
1
scopic data. The H NMR spectra of the praseodymium
donor complexes exhibit strong paramagnetic shifts, espe-
cially those of the cyclopentadienyl complexes.
Table 2. Bond lengths [Å] of selected literature (X–O)–M com-
plexes.
Experimental Section
Compound[a]
X–O(carbonyl) M–O(carbonyl)
General Procedures: All operations were performed with rigorous
exclusion of air and water by using glovebox techniques (MB Braun
MB150B-G glovebox; Ͻ 1 ppm O2, Ͻ 1 ppm H2O). Toluene was
purchased from Sigma–Aldrich (reagent grade) and passed through
Grubbs columns (MBraun SPS, solvent purification system). Sol-
vents were degassed by performing three freeze-pump-thaw cycles.
Benzophenone and 9-fluorenone were purchased from Fluka (GC
grade Ն 99% purity). Both were heated to 60 °C, dried under vac-
Tb[N(SiMe3)2]3(C=O)[10]
1.264(14)
1.219(2)
1.222(4)
1.256(10)
1.52(2)
1.401(4)
1.317(11)
1.334(6)
1.39(6)
2.305(9)
2.384(3)
2.342(3)
2.459(7)
2.40(2)
2.335(3)
2.234(7)
2.178(4)
2.11(3)
DyCp3(C=O)[11]
YCp3(C=O)[14]
CeCp3(C=O)[12]
La[N(SiMe3)2]3(P=O)[15a]
[25]
Na(C–O)ketyl
[16d]
[17]
Sm(C5Me5)2(thf)(C–O)ketyl
U[(tBuArO)3tacn](C–O)ketyl
[26]
uum for several hours, and admitted to the glovebox. Ce[N-
[Yb(hmpa)2(C–O)dianion 2
]
[27]
[29]
(SiMe3)2]3, Pr[N(SiMe3)2]3,[28] CeCp3, and PrCp3
were synthe-
[Li2(thf)(tmeda)(C–O)dianion 2
]
1.406
1.867(8)
sized according to literature procedures. NMR spectra were re-
corded with a Bruker Avance DMX400 spectrometer (5 mm BB,
1H: 400.13 MHz) in [D6]benzene at 25 °C. Deuterated benzene was
purchased from Deutero GmbH (99.5% purity) and was dried with
sodium metal. 1H NMR shifts are referenced to internal solvent
resonances and are reported relative to tetramethylsilane (TMS).
IR spectra were recorded with a Nicolet Impact 410 FTIR or a
Nicolet 6700 FTIR spectrometer equipped with a DRIFT chamber
with dry KBr/sample mixtures and KBr windows; the collected
data were converted by using the Kubelka–Munk refinement. Ele-
mental analyses were performed with an Elementar Vario Micro
Cube elemental analyzer.
[a] tacn = trianion of 1,4,7-tris(3,5-di-tert-butyl-2-hydroxybenzyl)-
1,4,7-triazacyclononane; hmpa hexamethylphosphoramide;
tmeda = tetramethylethylenediamine; thf = tetrahydrofuran.
=
The overall structural motif displayed by CeIII[N-
(SiMe3)2]3(ketone) and CeIII(C5H5)3(ketone) is also found
in the tetravalent derivatives CeIV[N(SiMe3)2]3(R) (R = Cl,
Br)[20] and CeIV(C5H5)3(R) (R = OtBu, Cl).[19b,21] Table 3
summarizes further crystallographic data for compounds 1–
4. FTIR spectroscopy for all complexes showed a general
decrease in the ν(C=O) vibration of the coordinated ketone
associated with the lengthening of the carbonyl bond. The
ν(C=O) of free Ph2CO[22] is found at 1649 cm–1, and that
of uncoordinated C13H8O[23] is found at 1712 cm–1. The co-
ordinated benzophenone complexes 1 and 3 show ν(C=O)
decreases of ca. 13 cm–1; however, the fluorenone complexes
2 and 4 show larger decreases (ca. 35 cm–1) upon rare-earth
metal coordination [for diffuse reflectance infrared Fourier
transform (DRIFT) spectra, see Supporting Information,
Figures S5 and S6]. As a general trend, the silylamide com-
plexes show a greater decrease in wavelength than the cyclo-
pentadienyl complexes (see Supporting Information). 1H
NMR spectroscopy was performed on all complexes despite
their paramagnetic nature. The proton signals found in
these complexes were sufficiently distant to allow for tenta-
tive assignments; however, all peaks were broad with signifi-
cant paramagnetic shifting, especially for the praseodym-
ium-based complexes.[24]
Ce[N(SiMe3)2]3·(Ph2C=O) (1a): Bright yellow Ce[N(SiMe3)2]3
(0.2000 g, 0.3219 mmol) was dissolved in toluene (5 mL), to which
a solution of benzophenone (0.0580 g, 0.3219 mmol) in toluene
(5 mL) was added in one portion with rapid stirring at ambient
temperature. Immediately, a color change from yellow to dark red
occurred. This solution was stirred for 0.5 h. A small amount of
precipitate was observed when the solution was filtered through a
glass frit. All volatiles were removed in vacuo to leave a red solid
(yield 90%). A concentrated toluene solution at –35 °C produced
red crystals suitable for X-ray diffraction measurement. IR
(DRIFT): ν
= 2952 (m), 2898 (w), 2120 (m, sh), 2066 (m),1997
˜
max
(m, sh), 1951 (m, sh), 1905 (m, sh), 1415 (w), 1251 (s), 956 (s), 889
1
(vs), 843 (s), 794 (m), 768 (m), 688 (w), 591 (w), 561 (w) cm–1. H
NMR (400 MHz, C6D6):
δ = –2.9, 6.8, 6.9, 8.2 ppm.
C31H64CeN3Si6 (787.50): calcd. C 46.34, H 8.03, N 5.23; found C
46.08, H 7.59, N 5.08.
Ce[N(SiMe3)2]3·(C13H8O) (2a): Bright yellow Ce[N(SiMe3)2]3
(0.2000 g, 0.3219 mmol) was dissolved in toluene (5 mL), to which
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a solution of 9-fluorenone (0.0580 g, 0.3219 mmol) in toluene
(5 mL) was added in one portion with rapid stirring at ambient
temperature. Immediately, a color change from yellow to dark
green occurred. This solution was stirred for 0.5 h. A small amount
of precipitate was observed when the solution was filtered. All vola-
tiles were removed in vacuo to leave a green solid (yield 90%). A
concentrated toluene solution at –35 °C produced green crystals
Pr[N(SiMe3)2]3·(C13H8O) (2b): Green Pr[N(SiMe3)2]3 (0.2000 g,
0.3219 mmol) was dissolved in toluene (5 mL), to which a solution
of 9-fluorenone (0.0570 g, 0.3210 mmol) in toluene (5 mL) was
added in one portion with rapid stirring at ambient temperature.
Immediately a color change from green to orange-red occurred.
This solution was stirred for 0.5 h. All volatiles were removed in
vacuo to leave an orange-red solid (yield 85%). A concentrated
toluene solution at –35 °C produced red crystals suitable for X-ray
suitable for X-ray diffraction measurement. IR (DRIFT): ν
=
˜
max
2947 (m), 2895 (m), 2134 (w), 1937 (w), 1845 (w), 1664 (s), 1609
(m), 1591(s), 1540 (w), 1245 (s), 1200 (m), 1157 (w), 1101 (m), 971
(vs), 923 (s), 860 (s), 832 (vs), 766 (m), 735 (m), 664 (m), 597 (s),
diffraction measurement. IR (DRIFT): ν
= 3065 (w), 2951 (m),
˜
max
2894 (m), 1712 (m, sh), 1698 (m, sh), 1681 (m, sh), 1662 (m), 1606
(m, sh), 1599 (m, sh), 1590 (m, sh), 1452 (m), 1302 (w), 1246 (s),
1198 (w), 1154 (w), 1098 (w), 994 (s), 969 (m), 920 (m), 861 (s, sh),
831 (vs, sh), 765 (m), 733 (m, sh), 667 (m), 599 (m) cm–1. 1H NMR
(400 MHz, C6D6): δ = –7.6, 0.2, 0.5, 2.2 ppm. C31H62N3OPrSi6
(802.27): calcd. C 47.41, H 7.79, N 5.24; found C 47.86, H 7.45, N
4.82.
1
506 (w), 442 (w) cm–1. H NMR (400 MHz, C6D6): δ = –3.0, 6.8,
7.8 ppm. C31H62CeN3OSi6 (801.49): calcd. C 46.46, H 7.80, N 5.24;
found C 42.56, H 7.53, N 4.75.
CeCp3·(Ph2C=O)
(3a):
Yellow-orange
CeCp3
(0.0627 g,
0.1869 mmol) was dissolved in toluene (5 mL), to which a solution
of benzophenone (0.0341 g, 0.1869 mmol) in toluene (5 mL) was
added in one portion with rapid stirring at ambient temperature.
Immediately, a color change from yellow to green occurred. This
solution was stirred for 0.5 h. A small amount of precipitate was
observed when the solution was filtered through a glass frit. All
volatiles were removed in vacuo to leave a green solid (yield 70%).
A concentrated toluene solution at –35 °C produced dark green
crystals suitable for X-ray diffraction measurement. IR (DRIFT):
PrCp3·(Ph2C=O) (3b): Green PrCp3 (0.0796 g, 0.1949 mmol) was
dissolved in toluene (5 mL), to which a solution of benzophenone
(0.0353 g, 0.1937 mmol) in toluene (5 mL) was added in one por-
tion with rapid stirring at ambient temperature. Immediately, a
color change from green to orange-red occurred. This solution was
stirred for 0.5 h. All volatiles were removed in vacuo to leave an
orange-red solid (yield 70%). A concentrated toluene solution pro-
duced orange-red crystals at –35 °C suitable for X-ray diffraction
ν
= 3057 (m), 2924 (s), 2854 (m), 1653 (s), 1634 (m), 1594 (m),
˜
max
measurement. IR (DRIFT): ν
= 3927 (w), 3085 (m), 3063 (m),
˜
max
1576 (m), 1490 (w), 1448 (s), 1278 (vs), 1176 (w), 1160 (m), 1076
(w), 1011 (m), 1000 (m), 945 (m), 919 (m), 866 (w), 812 (m), 766
3031 (w), 2952 (m), 2920 (m), 2854 (m), 2708 (w), 2411 (w), 2322
(w), 1657 (m), 1635 (s), 1600 (m), 1578 (m), 1492 (w), 1445 (m),
1325 (m), 1290 (m), 1280 (m), 1179 (w), 1160 (m), 1081 (m), 1014
(m), 948 (w), 916 (w), 846 (w), 815 (w, sh), 783 (vs), 761 (vs), 717
(s), 637 (m), 615 (vw), 451 (vw) cm–1. 1H NMR (400 MHz, C6D6):
δ = –10.9, 3.0, 4.4, 14.3 ppm. C28H25OPr (518.41): calcd. C 64.87,
H 4.86; found C 65.92, H 5.21.
1
(s), 707 (vs), 638 (m), 436 (w) cm–1. H NMR (400 MHz, C6D6): δ
= –0.28, 0.11, 0.27, 2.14, 2.22 ppm. C28H25CeO (517.62): calcd. C
65.23, H 4.50; found C 64.97, H 4.87.
CeCp3·(C13H8O)
(4a):
Yellow-orange
CeCp3
(0.0627 g,
0.1869 mmol) was dissolved in toluene (5 mL), to which a solution
of 9-fluorenone (0.0336 g, 0.1869 mmol) in toluene (5 mL) was
added in one portion with rapid stirring at ambient temperature.
Immediately, a color change from yellow to dark red occurred. This
solution was stirred for 0.5 h. A small amount of precipitate was
observed when the solution was filtered through a glass frit. All
volatiles were removed in vacuo to leave a red solid (yield 70%). A
concentrated toluene solution at –35 °C produced red crystals suit-
PrCp3·(C13H8O) (4b): Green PrCp3 (0.588 g, 1.4401 mmol) was dis-
solved in toluene (20 mL), to which a solution of 9-fluorenone
(0.2590 g, 1.4373 mmol) in toluene (10 mL) was added in one por-
tion with rapid stirring at ambient temperature. Immediately, a
color change from green to dark red occurred. This solution was
stirred for 0.5 h. A small amount of green precipitate was observed
when the solution was filtered through a glass frit. All volatiles
were removed in vacuo to leave a dark red solid (yield 82%). A
concentrated toluene solution at –35 °C produced dark red crystals
able for X-ray diffraction measurement. IR (DRIFT): ν
= 3065
˜
max
(m), 2924 (m), 2853 (m), 2125 (m), 1715 (s), 1688 (m), 1610 (m),
1599 (m), 1452 (w), 1302 (m), 1195 (w), 1152 (w), 1099 (w), 1015
(m), 919 (m), 879 (w), 813 (w, sh), 759 (m, sh), 735 (s), 671 (m),
650 (w), 442 (w) cm–1. 1H NMR (400 MHz, C6D6): δ = 0.7, 3.1,
6.7, 8.1 ppm. C28H23CeO (515.61): calcd. C 65.10, H 4.68; found
C 65.23, H 4.50.
suitable for X-ray diffraction measurement. IR (DRIFT): ν
=
˜
max
3925 (w), 3370 (w), 3082 (m, sh), 3068 (m, sh), 3016 (w, sh) 1838
(w), 1691 (vs), 1606 (m, sh), 1599 (m, sh), 1452 (m), 1304 (m), 1199
(m), 1157 (w), 1100 (m, sh), 1091 (m, sh), 1016 (m), 920 (m), 815
(m, sh), 789 (s, sh), 765 (s, sh), 742 (s, sh), 733 (vs, sh), 674 (m),
651 (w), 578 (w), 445 (w) cm–1. 1H NMR (400 Hz, C6D6): δ = –8.6,
–0.8, 2.6, 2.7, 14.7 ppm. C28H23OPr (516.40): calcd. C 65.13, H
4.49; found C 64.26, H 4.15.
Pr[N(SiMe3)2]3·(Ph2C=O) (1b): Green Pr[N(SiMe3)2]3 (0.2000 g,
0.3219 mmol) was dissolved in toluene (5 mL), to which a solution
of benzophenone (0.0580 g, 0.3219 mmol) in toluene (5 mL) was
added in one portion with rapid stirring at ambient temperature.
Immediately, a color change from green to yellow occurred. This
solution was stirred for 0.5 h. All volatiles were removed in vacuo
to leave a yellow solid (yield 86%). A concentrated toluene solution
at –35 °C produced yellow crystals suitable for X-ray diffraction
Crystal Data Collection, Structure Solution, and Refinement: All in-
tensity data, except for compound 4b, were collected with a Bruker
APEXII Ultra rotating anode CCD diffractometer. Data for com-
pound 4b were collected with a Bruker APEXII sealed-tube CCD
diffractometer. All data sets were collected with Mo-Kα radiation.
measurement. IR (DRIFT): νmax = 3082 (w, sh), 3065 (w), 3026 (w,
˜
sh), 2943 (m), 2892 (m), 1657 (m, sh), 1646 (m, sh), 1621 (m, sh), Raw data were reduced and scaled with the program SAINT,[30]
1609 (m, sh), 1592 (m, sh), 1568 (m, sh), 1492 (w), 1450 (m), 1331 and corrections for absorption effects were applied by using SAD-
(m, sh), 1319 (m, sh), 1291 (m), 1243 (m), 1182 (m), 1162 (w), 1074
(w, sh), 997 (m, sh) 972 (s, sh), 960 (s, sh), 860 (s, sh), 830 (vs, sh),
ABS.[30] The structures were solved by direct methods
(SHELXS[31]) and refined by full-matrix least-squares methods on
706 (s), 665 (m), 635 (m), 599 (m), 443 (w) cm–1. 1H NMR F2 using SHELXL-97.[31] The data collection parameters are given
(400 MHz, C6D6): δ = –7.5, 0.21, 0.25 ppm. C31H64N3PrSi6
(788.29): calcd. C 46.29, H 8.02, N 5.22; found C 46.48, H 7.79, N
4.50.
in Table 3. CCDC-903009 (for 1a), -903010 (for 1b), -903011 for
(2a), -903012 (for 2b), -903013 (for 3a), -903014 (for 3b), -903015
(for 4b), and -903016 (for 4a) contain the supplementary crystallo-
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Table 3. Crystallographic data for 1–4.
1a 2a
3a
4a
1b
2b
3b
4b
Empirical formula
Formula mass
Space group
a [Å]
b [Å]
c [Å]
C31H64CeN3OSi6 C31H62CeN3OSi6 C28H25CeO C28H23CeO C31H64PrN3OSi6 C31H62PrN3OSi6 C28H25PrO C28H23PrO
803.51
P21/n
801.50
P21/n
517.60
P1
515.58
P21/n
804.30
P21/n
802.29
P21/n
518.39
P1
516.37
P21/c
¯
¯
11.6507(4)
18.4720(6)
19.9659(7)
90
18.0565(5)
12.6307(4)
18.7501(5)
90
8.4777(4)
12.0338(6)
12.8471(7)
8.3038(3)
15.0119(6)
17.1369(6)
11.6145(5)
18.4997(8)
19.9616(9)
90
18.0810(9)
12.5950(6)
18.7413(9)
90
8.4463(7)
12.0405(9)
12.8056(15) 29.3633(10)
114.392(10) 90
8.7024(10)
8.3633(10)
α [°]
114.640(10) 90
β [°]
92.9991(4)
90
4291.0(3)
4
91.4728(4)
90
4274.9(2)
4
102.237(10) 90.36(1)
92.731(10)
90
91.436(10)
90
4266.6(4)
4
102.191(10) 98.17(10)
γ [°]
99.132(10)
1118.3(10)
2
90
99.194(10)
1113.8(18)
2
90
V [Å3]
2136.17(14) 4284.2(3)
4
2129.14(5)
4
Z
4
F(000)
T [K]
1684
113
1.244
1.254
0.0216
0.0592
1.069
1676
123
1.245
1.258
0.0241
0.0639
1.065
518
123
1028
123
1688
123
1680
123
1.249
1.336
0.0210
0.0559
1.042
520
123
1032
120
ρcalcd. [gcm–3]
μ [mm–1]
R1[a] (obsd.)
1.537
2.051
0.0288
0.0783
1.256
1.603
2.148
0.0216
0.0576
1.054
1.247
1.330
0.0231
0.0617
1.049
1.546
2.203
0.0225
0.0614
1.104
1.611
2.305
0.0196
0.0429
1.156
[b]
wR2 (all)
S[c]
[a] R1 = Σ(|Fo| – |Fc|)/Σ|Fo|, Fo Ͼ 2σ(Fo). [b] wR2 = {Σ[w(Fo – Fc ) ]/Σ[w(Fo2)2]}1/2. [c] S = [Σw(Fo – Fc ) /(no – np)]1/2
.
2
2 2
2
2 2
[12]
[13]
[14]
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Received: September 27, 2012
Published Online: November 26, 2012
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© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim