Multimetallic synergic sedation of a labile sodium atrane: Synthesis and characterization of a tetranuclear sodium atrane cation complex

Article abstract of DOI:10.1021/ic2013123

A series of sodium and aluminum atrane complexes of Na₃L(THF) ₅ (1), [AlLMe][Na₄L(THF)₆] (2), AlL(THF) (3), AlNaLMe(THF)₂ (4), and AlNaLOBn(THF)₂ (5), wherein L = tris(2-oxy-4,6-di-tert-butyl-benzyl)amine, were synthesized and characterized by NMR, X-ray crystallography, and elemental analysis. The trinuclear sodium atrane complex of Na₃L(THF)₅ (1) is labile at room temperature; however, the tetranuclear sodium atrane cation in complex 2 can be stabilized by a multimetallic synergetic effect due to a firm interaction ring of -[Na-O-benzene]₃-. Complex 2 is also the first example of a sodatrane and alumatrane ion-paired complex in which both the cationic and anionic moieties contain an atrane ligand.

Full text of DOI:10.1021/ic2013123

ARTICLE
pubs.acs.org/IC
Multimetallic Synergic Sedation of a Labile Sodium Atrane: Synthesis
and Characterization of a Tetranuclear Sodium Atrane Cation
Complex
Jinfeng Zhang,† Ai Liu,† XiaoBo Pan, Lihui Yao, Lei Wang, Jianguo Fang, and Jincai Wu*
Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic
Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, People’s Republic of China
S Supporting Information
b
ABSTRACT: A series of sodium and aluminum atrane complexes of Na3L(THF)5 (1),
[AlLMe][Na4L(THF)6] (2), AlL(THF) (3), AlNaLMe(THF)2 (4), and AlNaLOBn-
(THF)2 (5), wherein L = tris(2-oxy-4,6-di-tert-butyl-benzyl)amine, were synthesized and
characterized by NMR, X-ray crystallography, and elemental analysis. The trinuclear
sodium atrane complex of Na3L(THF)5 (1) is labile at room temperature; however, the
tetranuclear sodium atrane cation in complex 2 can be stabilized by a multimetallic
synergetic effect due to a firm interaction ring of À[NaÀOÀbenzene]3À. Complex 2 is
also the first example of a sodatrane and alumatrane ion-paired complex in which both the
cationic and anionic moieties contain an atrane ligand.
cyclic esters. Thus, some multimetallic complexes have been
synthesized, and some interesting synergic effects were observed.8
Here, we report a new synergic effect in the stabilization of a
special tetrasodium atrane cation with tripodal aminetris(phenol)
as the ligand.
1. INTRODUCTION
Multimetallic coordination chemistry has attracted consider-
able interest due to some special synergic effects. The enzyme
of nitrogenase, for example, includes heterometallic complexes
(e.g., Fe, Mo, and Co) at the active site in which the multimetallic
synergic effect plays a key role in the fixation of atmospheric
nitrogen gas.1 Some heterobimetallic complexes applied as
asymmetric catalysts can efficiently promote many reactions
through a synergetic cooperation between two different metals,2
and the heterobimetallic complex of “iBu3Al(TMP)Li”(TMP(H) =
2,2,6,6-tetramethylpiperidine) exhibits high chemo- and regios-
electivity in proton abstraction reactions of functionalized aro-
matic substrates because of alkali-metalÀaluminum synergic
effects.3 Recently, Mulvey et al. published extensive and excellent
work on the applications of mixed-metal molecular synergy, such
as the extraordinary synergic sedation of sensitive cyclic ether and
ethene anions by alkali-mediated zincation4 and the quantitative
regioselective tetramagnesiation of ferrocene, ruthenocene, and
osmocene (which cannot be directly magnesiated by any known
conventional organomagnesium reagent by an alkali-metal-mediated
magnesiation approach).5 They have also reported the activation
of arene by multimetallic inverse crown complexes6 and the self-
deprotonation/metalation of the TMP anion in a KÀAl hetero-
bimetallic complex, which is unlikely to be reproduced in a
homometallic system under a controlled manner.7
An atrane is tricyclic molecule with three five- or six-mem-
bered rings and a transannular bond. Atranes have attracted
the interest of many chemists because they can be used to stabi-
lize unusual metal coordination geometries,9 unusual inorganic
functionalities,10 and catalytically active species.11 The tripodal
aminetris(phenol), when acting as an atrane ligand with one
nitrogen and three oxygen coordination atoms, usually binds to a
metal in a tetradentate manner to give the settled coordinating
environment; five-coordinate trigonal bipyramidal complexes are
most commonly observed with another simple coordinated
ligand at the apical position. Because of the ease with which
steric and electronic modulation are induced by changes in the
substituents on the aryl rings, tripodal aminetris(phenol) ligands
have been widely used to synthesize many kinds of atranes such
as silicon,12 phosphorus,13 titanium,14 tantalum,15 indium,16
vanadium,17 iron,18 and germanium19 atranes. Among the known
atranes, sodatrane remains relatively unexplored. To the best of
our knowledge, the sodium complexes of aminetriethanol re-
ported by Verkade et al. are the only examples of sodatranes,20
Recently, our research has focused on the development of
multimetallic catalysts for the ring-opening polymerization of
Received: June 17, 2011
Published: September 08, 2011
r
2011 American Chemical Society
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Scheme 1. Synthesis of Complexes 1À5
and aminetris(phenol)-supported sodium atrane has not been
previously reported.
approximately 8% of compound 6 as the side product, as
evidenced by the analysis of the NMR spectrum. The experiment
also shows that H2O can accelerate the decomposition because
the reaction of NaOH and aminetris(phenol) gives compound 6
in 1 h with a conversion of approximately 50% at room
temperature. As other researches have previously reported, this
aminetris(phenol) ligand is stable after coordination to highly
charged metals, such as those in Al3+, Ti4+, or Fe3+ complexes.
Therefore, the lability of the sodium atrane complex 1 is
attributed to the weak coordination interaction between the
sodium cation and the aminetris(phenol) ligand. The geometry
of the atrane cannot be fixed like other highly Lewis-acidic metal
complexes; thus, the aminetris(phenol) ligand decomposes to
compound 6, possibly via an approach similar to that in Scheme 2.
During the synthesis of the heterometallic aluminum sodium
alkoxide of complex 5 as a potential initiator for the ring-opening
polymerization of lactides,22 an interesting complex (2) was
found as a first example of a sodatrane and alumatrane ion-paired
complex (Scheme 1). This complex also contains the first example
2. RESULTS AND DISCUSSION
The trinuclear sodium atrane of complex 1 was designed as a
precursor (Scheme 1) for the synthesis of new catalysts for the
ring-opening polymerization of lactides. The tripodal aminetris-
(phenol) (tris(4,6-di-tert-butyl-2-hydroxybenzyl)amine) ligand,
however, is not stable under basic conditions: the reaction of
aminetris(phenol) and sodium metal/NaH/NaOH gives a mix-
ture of complex 1 and the side product of compound 6 (6,8-di-
tert-butyl-3-(3,5-di-tert-butyl-2-hydroxybenzyl)-2H-3,4-dihydro-
benz-1,3-oxazine) at room temperature, which can usually be
obtained by the reaction of phenol and urotropine under Duff
reaction conditions.21 The purification of complex 1 for sequent
decomposition at room temperature is difficult. Low-purity
complex 1 can only be obtained by a cooling reaction of NaH
and aminetris(phenol) in dry THF at À20 °C, together with
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Scheme 2. Possible Decomposition Mechanism of Aminetris(phenol) under Basic Conditions
Complex 2 was obtained by stirring a mixture of 4 equivalents
of sodium, 1 equivalent of AlMe3, and 2 equivalents of tris(4,6-di-
tert-butyl-2-hydroxybenzyl)amine in THF at 50 °C. Fine crystals
of complex 2 were obtained from a saturated solution in THF/
hexane at room temperature with 53% yield. Complex 2 contains
one sodatrane cation and one alumatrane anion. The structure of
the tetrasodium cation in complex 2, depicted in Figure 1, reveals
a well-defined sodatrane composed of a center Na+ and aminetri-
sphenoxy. The geometry around the center Na+ is an unprece-
dented trigonal pyramid, and the opposite position of N is
unoccupied, which is different from the prevalent five-coordinate
trigonal bipyramidal metal atrane complex. Intriguingly, this
sodatrane can attract three Na+ ions. Each Na+ ion is stabilized
by the coordination of two THF molecules, one oxygen atom
of phenol, and the pÀπ interaction between the Na+ and
benzene ring of the ligand with an average distance of 2.743(7) Å.
The latter two interactions for Na+ form another ring, À
[NaÀOÀbenzene]3À, depicted in Figure 1 as the green ring. As
the anion component (Figure 2), the alumatrane apparently
binds one methyl group at the apical position of a trigonal
bipyramid with a CÀAl bond distance of 1.984(7) Å. Compared
to the aluminatrane complex 3 (Figure 3), which was synthesized
by the reaction of AlMe3 and aminetris(phenol) ligand in THF at
80 °C, the long N1ÀAl1 bond with a distance of 2.289(7) Å in
the anion of complex 2 consists of an electron-rich methyl group
anchored on the aluminum center.
Although complex 1 is very labile to moisture, several crystals
of complex 1 were picked up from the reaction mixture, which
indicated the slight stability of complex 1 in the solid state. The
structure of complex 1 drawn in Figure 4 shows that the center
Na+ ion and the ligand form a three-bladed turbine that features
sodatrane. The structure also shows that the other two Na+ ions
occupy the two vacancies of the three-bladed turbine with
coordination of two oxygen atoms from the ligand and two
oxygen atoms from two THF molecules. No pÀπ interactions
occur between the benzene ring and the Na+ ion, which is
differentfromthe tetrasodiumatranecation incomplex 2. Another
difference is that the center Na+ is normally five-coordinate,
Figure 1. The tetranuclear sodium atrane cation of complex 2 (methyl
carbons of the tert-butyl groups and all of the hydrogen atoms omitted
for clarity). The coordination of the oxygen atoms of phenol to Na1/
Na2/Na3 and the pÀπ interaction between the Na+ and benzene ring of
the ligand form a À[NaÀOÀbenzene]3 interaction ring that is colored
in green. Selected bond lengths (Å): Na1ÀO4, 2.222(5); Na1ÀO8,
2.323(6); Na1ÀO7, 2.380(6); Na2ÀO5, 2.216(6); Na2ÀO10, 2.376(6);
Na2ÀO9, 2.400(7);Na3ÀO6, 2.197(6);Na3ÀO11, 2.363(7); Na3ÀO12,
2.381(6); Na4ÀO4, 2.222(5); Na4ÀO6, 2.235(6); Na4ÀO5, 2.247(7);
Na4ÀN2, 2.447(7).
of a tetranuclear monomeric sodium atrane cation. As far as we
know, no other separated ion-paired atrane complexes are known
in which both the cationic and anionic moieties contain an atrane
ligand. Because of the lability of the trinuclear sodium atrane of
complex 1, the presence of the stable tetrasodium atrane of
aminetrisphenoxide attracted our attention, and we assumed that
an interesting synergetic effect stabilized the tetranuclear sodium
atrane cation in complex 2.
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Figure 4. Molecular structure of complex 1 as 30% ellipsoids (methyl
carbons of the tert-butyl groups and all of the hydrogen atoms omitted
for clarity). Selected bond lengths (Å): Na1ÀO1, 2.222(11); Na1ÀO2,
2.133(11); Na1ÀN1, 2.367(5); Na1ÀO3, 2.442(5); Na1ÀO5, 2.281(7).
Figure 2. The aluminum atrane anion of complex 2 (methyl carbons of
the tert-butyl groups and all of the hydrogen atoms omitted for clarity).
Selected bond lengths (Å): Al1ÀO1, 1.775(5); Al1ÀO2, 1.790(6);
Al1ÀO3, 1.801(5); Al1ÀC46, 1.984(7); Al1ÀN1, 2.289(7).
after recrystallization. Therefore, a synergetic effect stabilizes the
tetrasodium atrane cation in complex 2, which we attribute primarily
to the firm interaction ring of À[NaÀOÀbenzene]3À that resulted
from the pÀπ interaction and the coordination of oxygen. Com-
pared to complex 1, the additional pÀπ interactions between the
Na+ and benzene ring of the ligand in complex 2 can fix the position
of phenol and decrease the nucleophilicity of oxygen and nitrogen
atoms; the tetrasodium atrane can therefore be stabilized.
To check this synergetic effect in the tetranuclear sodium
cation, the reaction of aminetris(phenol) ligand with 1 equivalent
of NaB(Ph)4 and 3 equivalents of NaH was conducted at 0 °C in
a mixed solvent of CH3OH and THF for 0.5 h. The mixture was
then warmed to room temperature under a moist air atmosphere.
The results show that the ligand is stable and that no compound 6
can be found by analysis of the NMR and mass spectra of the
reaction mixture. One mass peak at 1047.8 was observed, which is
attributed to the tetrasodium cation [Na4L(THF)4]+ (Figure S1,
Supporting Information).
We also attempted to use complex 2 to synthesize a catalyst.
The reaction between complex 2 and BnOH was conducted and
gave complex 5. Understandably, the benzyloxy that is substi-
tuted for the methyl group is so basic that one Na+ is attracted
back to the alumatrane anion from the tetrasodium atrane cation
to form the neutral complex 5. Complex 5 can also be obtained
by reflux of a mixture of BnOH and complex 4 in THF. The
structure of complex 5 shows that the benzyloxy bridges sodium
and aluminum atoms. The benzyloxy also locates at the apical
position of a trigonal bipyramid (Figure 5). Complex 5 can work
as an initiator for the ring-opening polymerization of lactide/
lactone, which will be reported in a forthcoming paper.
In conclusion, the first example of a sodatrane and alumatrane
ion-paired complex 2 is reported. The trinuclear sodium atrane of
complex 1 is very labile; however, the tetranuclear sodium atrane
cation in complex 2 is stable, possibly because of the multi-
metallic synergetic effect.
Figure 3. Molecular structure of complex 3 as 30% ellipsoids (methyl
carbons of the tert-butyl groups and all of the hydrogen atoms omitted
for clarity). Selected bond lengths (Å): Al1ÀO1, 1.752(5); Al1ÀO3,
1.753(4); Al1ÀO2, 1.760(4); Al1ÀO4, 1.976(4); Al1ÀN1, 2.026(5).
as are the other atrane metal complexes, whereas the center Na+
in complex 2 is unwontedly four-coordinate.
Complex 1 can be considered the precursor of complex 2
despite its lability. As another precursor of complex 2, complex 4
can be obtained by heating a mixed solution of 1 equivalent of
sodium, 1 equivalent of AlMe3, and the ligand. Therefore, we
propose that the formation mechanism of complex 2 involves the
extraction of Na+ from complex 4 to complex 1. A stable
tetranuclear sodium cation then forms; i.e., alumatrane binds
Na+ loosely. The driving force for the formation of the ion-paired
complex 2 is possibly the greater stability of the tetrasodium
atrane cation relative to the trisodium atrane. The tetrasodium
atrane cation is stable even in hot THF solution, whereas pure
complex 1 cannot be obtained in hot THF solution. A greater
amount of compound 6 appears under the same conditions, even
3. EXPERIMENTAL SECTION
General Procedures. All solvents were dried before use. Com-
mercial chemicals were purchased and used without further purification.
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Synthesis of Complex 3. A solution of tris(4,6-di-tert-butyl-2-hydro-
xybenzyl)amine (0.671 g, 1.0 mmol) and 1.2 mmol Al(Me)3 (1.0 mol/L
in hexane) was stirred in toluene (10 mL) at 80 °C under a N2
atmosphere for 12 h. The solvent was removed under vacuum condi-
tions to afford a white solid. Colorless crystals were obtained by cooling a
hot THF solution of complex 3. Yield: 0.62 g (81%). Anal. Calcd for
C49H74NAlO4: C, 76.62; H, 9.71; N 1.82. Found: C, 76.34; H, 9.53; N,
1.60. 1H NMR (CDCl3, 200 MHz): δ (ppm) 7.22 (s, Ph, 3H), 6.83 (s,
Ph, 3H), 4.50(b, OCH2CH2, 4H), 4.16À4.18(b, NCH2, 3H), 3.58À3.60
(b, NCH2, 3H), 2.09 (b, OCH2CH2, 4H), 1.41 (s, t-Bu, 27H), 1.26 (s,
t-Bu, 27H). 13C NMR (CDCl3, 50 MHz): 154.95, 139.07, 137.11, 123.76,
123.59, 121.56, 71.60, 58.69, 34.91, 34.00, 31.69, 29.75, 25.30.
Synthesis of Complex 4. A solution of tris(4,6-di-tert-butyl-2-hydro-
xybenzyl)amine (0.671 g, 1.0 mmol) and sodium (0.025 g, 1.2 mmol)
was stirred in THF (10 mL) at 50 °C under a N2 atmosphere until the
sodium dissolved completely. Then, Al(Me)3 (1.2 mL, 1 mol/L in
hexane) was slowly added to the solution. After the mixture was stirred
for 12 h, the solvent was removed under vacuum conditions to afford a
white solid. The white solid was dissolved in hexane. The hexane
solution was then filtered through Celite, and the filtrate was stored
for several days at room temperature. Colorless crystals were obtained.
Yield: 0.53 g (61%). Anal. Calcd for C54H85NAlNaO5: C, 73.85; H, 9.76;
N 1.59. Found: C, 74.01; H, 9.83; N, 1.80. 1H NMR (CDCl3, 400 MHz):
δ (ppm) 7.14À7.13 (d, J = 4.0 Hz, Ar-H, 3H), 6.79À6.78 (d, J = 4 Hz,
Ar-H, 3H), 4.16À4.13(d, J = 12.0 Hz, NCH2,3H), 3.53 (b, OCH2CH2,
12H), 2.71À2.68 (d, J = 12.0 Hz, NCH2, 3H), 1.75 (b, OCH2CH2,
12H), 1.40 (s, t-Bu, 27H), 1.25 (s, t-Bu,27H), À0.703 (s, AlCH3, 3H).
13C NMR (CDCl3, 100 MHz): 155.8, 137.8, 136.7, 123.3, 122.9, 122.5,
68.1, 59.9, 34.7, 33.9, 31.7, 29.6, 25.4.
Synthesis of Complex 5. Method A. To a rapidly stirred solution of
complex 4 (0.53 g, 0.61 mmol) in toluene (25 mL) was added BnOH
(1 mL, 1 M in toluene) at 50 °C. Stirring was continued for 12 h, and the
solvent was removed under vacuum conditions to afford a white solid.
The white solid was dissolved in a mixture of 5 mol of THF and 20 mL of
hexane. The mixture solution was then filtered through Celite, and the
filtrate was stored for several days at room temperature. Colorless
crystals were obtained. Yield: 0.42 g (71%).
Figure 5. Molecular structure of complex 5 as 30% ellipsoids (methyl
carbons of the tert-butyl groups and all of the hydrogen atoms omitted
for clarity). Selected bond lengths (Å): Al1ÀO2, 1.773(3); Al1ÀO1,
1.794(3); Al1ÀO6, 1.822(3); Al1ÀO3, 1.835(3); Al1ÀN1, 2.130(3);
Al1ÀNa1, 3.077(3); Na1ÀO6, 2.267(3); Na1ÀO4, 2.299(4);
Na1ÀO5, 2.300(4); Na1ÀO3, 2.410(3).
Tris(4,6-di-tert-butyl-2-hydroxybenzyl)amine was prepared according
to the method reported in the literature.23 Mass spectroscopic data were
obtained from a Bruker APEX II (FT-ICR MS), and NMR spectra were
recorded using spectrometers of the Varian Mercury Plus family.
Synthesis of Complex 1. A solution of tris(4,6-di-tert-butyl-2-hydro-
xybenzyl)amine (0.671 g, 1.0 mmol) and NaH (0.076 g, 3.15 mmol) was
stirred in THF (15 mL) at À20 °C under a N2 atmosphere for 12 h. The
solvent was then removed under vacuum conditions to afford a white
solid. For the subsequent decomposition of complex 1 at room
temperature, only mixtures of complex 1 and compound 6 (about
8%) were obtained. 1H NMR (CDCl3, 200 MHz) for the mixture of
1 and 6: δ (ppm) 7.27À7.19 (b, ArÀH), 6.89 (s, Ar-H), 6.85(s, Ar-H),
6.81(s, Ar-H), 4.84 (s, OCH2N), 4.05(s, NCH2, 4H), 3.64(s, NCH2),
1.44 (s, t-Bu), 1.40 (s, t-Bu), 1.35 (s, t-Bu), 1.27 (s, t-Bu) 1.25(s, t-Bu).
Method B. A solution of tris(4,6-di-tert-butyl-2-hydroxybenzyl)amine
(0.671 g, 1.0 mmol) and sodium (0.050 g, 2.2 mmol) was stirred in THF
(15 mL) at 50 °C under a N2 atmosphere until the sodium dissolved
completely. Then, Al(Me)3 (0.6 mL, 1 mol/L in hexane) was slowly
added to the solution. After the mixture was stirred for 12 h, the solvent
was removed under vacuum conditions to afford a white solid. The white
solid was dissolved in 15 mol of toluene, and BnOH (1 mL, 1 M in
toluene) was added. After the mixture was stirred for 24 h, the solvent
was removed under vacuum conditions to afford a white solid. The white
solid was dissolved in 5 mol of THF and 20 mL of hexane. The mixture
was then filtered through Celite, and the filtrate was stored for several
days at room temperature. Colorless crystals were obtained. Yield: 0.51 g
(52%). Anal. Calcd for C60H89NAlNaO6: C, 74.27; H, 9.25; N 1.44.
1
NMR data for compound 6, H NMR (CDCl3, 300 MHz): δ (ppm)
9.81 (s, O-H, 1H), 7.27 (d, J = 1.8 Hz, Ar-H, 1H), 7.21 (d, J = 1.8 Hz, Ar-
H, 1H), 6.85 (d, J = 2.1 Hz, ArÀH, 1H), 6.81 (d, J = 2.4 Hz, Ar-H, 1H),
4.84 (s, OCH2N, 2H), 4.05(S, NCH2, 4H), 1.44 (s, t-Bu, 9H), 1.40 (s,
t-Bu, 9H), 1.28 (s, t-Bu, 9H), 1.26 (s, t-Bu, 9H). 13C NMR (CDCl3, 300
MHz): 154.10, 149.92, 142.89, 141.06, 136.89, 135.88, 124.33, 123.42,
122.30, 120.48, 117.89, 79.64, 55.49, 49.99, 34.91, 34.30, 34.17, 31.64,
31.53, 29.69, 29.62.
Synthesis of Complex 2. A solution of tris(4,6-di-tert-butyl-2-hydro-
xybenzyl)amine (0.671 g, 1.0 mmol) and sodium (0.050 g, 2.2 mmol)
was stirred in THF (15 mL) at 50 °C under a N2 atmosphere until the
sodium dissolved completely. Then, Al(Me)3 (0.6 mL, 1 mol/L in
hexane) was slowly added to the solution. After the mixture was stirred
for 12 h, the solvent was removed under vacuum conditions to afford a
white solid. The white solid was dissolved in a mixture solvent of 5 mL
THF and 10 mL hexane. The solution was then filtered through Celite,
and the filtrate was stored for several days at room temperature.
Colorless crystals were obtained. Yield: 0.52 g (53%). Anal. Calcd for
C115H183N2AlNa4O12: C, 72.48; H, 9.73; N 1.47. Found: C, 72.01; H,
9.33; N, 1.20. 1H NMR (CDCl3, 300 Hz): δ (ppm) 7.18(s, Ph, 3H), 7.07
(s, Ph, 6H), 6.75À6.74 (m, Ph, 3H), 4.19À4.15 (d, J = 12 Hz, NCH2,
6H), 3.60 (b, OCH2CH2, 8H), 2.59À2.55 (d, J = 12 Hz, NCH2, 6H),
1.84 (b, OCH2CH2, 24H), 1.40 (s, t-Bu, 27H), 1.33 (s, t-Bu, 27H), 1.26
(s, t-Bu, 54H), À0.737 (s, AlCH3, 3H). 13C NMR (CDCl3, 75 MHz):
136.9, 136.6, 130.88, 127.0, 123.4, 122.1, 121.7, 68.1, 59.9, 35.1, 34.8,
33.8, 31.9, 29.5, 25.3.
1
Found: C, 74.60; H, 9.73; N, 1.21. H NMR (CDCl3, 200 MHz):
δ (ppm) 7.57, 7.54(d, PhCH2, 2H), 7.36À7.33 (m, PhCH2, 3H), 7.17
(s, Ph, 3H), 6.8 (s, Ph, 3H), 5.39À5.33 (d, J = 12.8 Hz, PhÀCH2, 1H),
5.10À5.03 (d, J = 12.8 Hz, PhÀCH2, 1H), 4.21À4.14 (d, J = 13.2 Hz,
NCH2, 3H), 3.48 (b, OCH2CH2, 8H), 2.75À2.69 (d, J = 13.2 Hz,
NCH2, 3H), 1.73 (b, OCH2CH2, 8H), 1.42 (s, t-Bu, 27H), 1.25 (s,
t-Bu,27H). 13C NMR (CDCl3, 50 MHz): 156.1, 148.58, 137.8, 136.5,
128.5, 127.8, 127.3,126.9, 125.5, 123.3, 122.9, 122.5, 68.1, 65.4, 59.9,
34.7, 34.5, 33.9, 31.7, 29.8, 25.3.
Crystallographic Studies. The X-ray single-crystal data collec-
tions were performed at room temperature on a Bruker SMART APEX
CCD diffractometer using graphite-monochromated Mo Kα (λ =
0.71073 Å) radiation. Semiempirical absorption corrections were
applied using the SADABS program. The structures were solved by
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Table 1. Crystal Data and Structure Refinements for Complexes of 1, 2, 3, and 5
1
2
3
5
formula
fw
C
65H106NNa3O8
C119H191AlNNa4O13
1968.61
C49H74AlNO4
768.07
C60H89AlNNaO6
970.29
1098.48
temp
cryst syst
space group
a, Å
296(2)
296(2)
296(2)
296(2)
monoclinic
P2(1)
triclinic
monoclinic
P2(1)/n
14.368(5)
19.641(7)
16.530(6)
90.00
monoclinic
P2(1)/n
P1
11.073(6)
26.684(15)
11.873(7)
90.00
16.87(4)
20.35(5)
21.04(5)
73.39(3)
87.13(3)
70.489(2)
6413(27)
2
17.507(13)
16.057(12)
22.567(17)
90.00
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Å3
Z
104.451(7)
90.00
92.672(4)
90.00
102.29(3)
90.00
3397(3)
2
4660(3)
4
6198(8)
4
density (calcd) g cmÀ3
absorb. coeff. mmÀ1
1.074
1.020
1.095
1.040
3
0.085
0.082
0.085
0.084
F(000)
1200
2144
1680
2112
θ range
2.25À27.93
À14 e h e 14
À35 e k e 34
À15 e l e 14
13424/324/628
0.782
3.16À25.00
À20 e h e 19
À19 e k e 24
À25 e l e 25
19794/0/1240
0.718
2.11À22.65
À14 e h e 15
À21 e k e 18
À17 e l e 17
6147/0/484
1.026
1.57À26.10
À21 e h e 21
À19 e k e 16
À26 e l e 27
12107/0/622
0.842
index ranges
data/restr./params
GOF
final R indices
0.0742
0.0788
0.0843
0.0700
[I > 2σ(I)]
0.1663
0.1361
0.2224
0.1887
peak and hole e.ÅÀ3
CCDC number
0.176À0.176
824606
0.299À0.160
824607
0.896 À0.605
824605
0.892À0.240
824608
direct methods and refined by full-matrix least-squares on F2 using the
SHELXS-97 and SHELXL-97 programs.24 Anisotropic thermal para-
meters were assigned to all non-hydrogen atoms. The hydrogen atoms
were set in calculated positions and refined as riding atoms with a
common fixed isotropic thermal parameter. The crystal data and
refinement results are summarized in Table 1.
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’ ACKNOWLEDGMENT
Financial support from the National Natural Science Founda-
tion of China (No. 21071069 and 21002047) is gratefully
acknowledged.
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