Amido phosphine complexes of zinc: Synthesis, structure, and catalytic ring-opening polymerization of ε-caprolactone

Article abstract of DOI:10.1039/c0dt00327a

A series of diarylamido phosphine ligands of the type N-(2- dihydrocarbylphosphinophenyl)-2,6-dialkylanilide 1a-d have been prepared and employed to investigate the coordination chemistry of zinc. Protonolysis of ZnMe₂ with one equivalent of N-(2-diphenylphosphinophenyl)-2,6- dimethylaniline (H[1a]) produced a mixture of [1a]ZnMe (2a) and Zn[1a] ₂ (4a), whereas that involving ZnEt₂ gave exclusively the three-coordinate [1a]ZnEt (3a). In contrast, treatment of ZnR₂ (R = Me, Et) with N-(2-diphenylphosphinophenyl)-2,6-diisopropylaniline (H[1b]), N-(2-diisopropylphosphinophenyl)-2,6-dimethylaniline (H[1c]), or N-(2-diisopropylphosphinophenyl)-2,6-diisopropylaniline (H[1d]) under similar conditions generated quantitatively the corresponding three-coordinate zinc methyl 2b-d and zinc ethyl 3b-d. The bis-ligand complexes 4a,b,d were isolated by either protonolysis of alkyls 2-3 with one equivalent of H[1] or metathesis of ZnX₂ (X = Cl, OAc) with the corresponding lithium derivatives 5. Attempts to prepare [1a-d]ZnX (X = Cl, OAc) were not successful regardless of stoichiometry of the starting materials employed. Alcoholysis of zinc alkyls 2-3 led undesirably to protonation on the amido nitrogen donor of 1, highlighting perhaps its higher basicity than alkyls. The reaction of ZnCl₂ with H[1c] generated the phosphorus-bound adduct {H[1c]ZnCl(μ-Cl)}₂ (6c). Interestingly, attempts to deprotonate 6c with n-BuLi produced unexpectedly the alkylated product [1c]Zn(n-Bu) (7c) instead of [1c]ZnCl; analogous reactions employing NEt₃ led to Lewis base substitution to give H[1c] and [ZnCl₂(NEt₃)]₂. Structural characterization of all new compounds was achieved by multi-nuclear NMR spectroscopy (¹H, ¹³C, ³¹P, and ⁷Li) and X-ray crystallography (2c-d, 3c, 4d, 5c-d, and 6c) where appropriate. On the basis of the NMR and X-ray data, in combination with the synthetic investigations, the steric nature of these amido phosphine ligands is recognized to follow the order of 1a < 1b < 1c < 1d. Interestingly, zinc alkyls 2-3 are all active initiators for catalytic ring-opening polymerization of ε-caprolactone whereas the bis-ligand complexes 4 are not.

Full text of DOI:10.1039/c0dt00327a

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Amido phosphine complexes of zinc: synthesis, structure, and catalytic
ring-opening polymerization of e-caprolactone†
Lan-Chang Liang,*a Wei-Ying Lee,a Tzung-Ling Tsai,a Yu-Lin Hsua and Ting-Yu Leeb
Received 19th April 2010, Accepted 10th June 2010
DOI: 10.1039/c0dt00327a
A series of diarylamido phosphine ligands of the type N-(2-dihydrocarbylphosphinophenyl)-2,6-
dialkylanilide 1a–d have been prepared and employed to investigate the coordination chemistry of zinc.
Protonolysis of ZnMe2 with one equivalent of N-(2-diphenylphosphinophenyl)-2,6-dimethylaniline
(H[1a]) produced a mixture of [1a]ZnMe (2a) and Zn[1a]2 (4a), whereas that involving ZnEt2 gave
exclusively the three-coordinate [1a]ZnEt (3a). In contrast, treatment of ZnR2 (R = Me, Et) with
N-(2-diphenylphosphinophenyl)-2,6-diisopropylaniline (H[1b]), N-(2-diisopropylphosphinophenyl)-
2,6-dimethylaniline (H[1c]), or N-(2-diisopropylphosphinophenyl)-2,6-diisopropylaniline (H[1d]) under
similar conditions generated quantitatively the corresponding three-coordinate zinc methyl 2b–d and
zinc ethyl 3b–d. The bis-ligand complexes 4a,b,d were isolated by either protonolysis of alkyls 2–3 with
one equivalent of H[1] or metathesis of ZnX2 (X = Cl, OAc) with the corresponding lithium derivatives
5. Attempts to prepare [1a–d]ZnX (X = Cl, OAc) were not successful regardless of stoichiometry of the
starting materials employed. Alcoholysis of zinc alkyls 2–3 led undesirably to protonation on the amido
nitrogen donor of 1, highlighting perhaps its higher basicity than alkyls. The reaction of ZnCl2 with
H[1c] generated the phosphorus-bound adduct {H[1c]ZnCl(m-Cl)}2 (6c). Interestingly, attempts to
deprotonate 6c with n-BuLi produced unexpectedly the alkylated product [1c]Zn(n-Bu) (7c) instead of
[1c]ZnCl; analogous reactions employing NEt3 led to Lewis base substitution to give H[1c] and
[ZnCl2(NEt3)]2. Structural characterization of all new compounds was achieved by multi-nuclear NMR
spectroscopy (1H, 13C, 31P, and 7Li) and X-ray crystallography (2c–d, 3c, 4d, 5c–d, and 6c) where
appropriate. On the basis of the NMR and X-ray data, in combination with the synthetic investigations,
the steric nature of these amido phosphine ligands is recognized to follow the order of 1a < 1b < 1c <
1d. Interestingly, zinc alkyls 2–3 are all active initiators for catalytic ring-opening polymerization of
e-caprolactone whereas the bis-ligand complexes 4 are not.
istry with zinc, aiming at the development of active initiators for
Introduction
catalytic polymerization of heterocycles. In this contribution, we
Organozinc complexes and their derivatives have long been recog-
describe the preparation and structural characterization of these
nized as useful reagents for stoichiometric and catalytic chemical
transformations.1 The non-toxic, inexpensive, and biocompatible
molecules and demonstrate their reactivity with respect to catalytic
ring-opening polymerization (ROP) of e-caprolactone (e-CL).
nature of zinc2 makes it an attractive candidate as initiators for
Solution NMR spectroscopic and X-ray crystallographic data
biocompatible polymer synthesis.3,4 With sterically demanding
concerning the electronic and steric properties of these molecules
ligands, zinc complexes have shown remarkable activities to
are also discussed. A preliminary result of synthetic investigations
catalytically polymerize a number of heterocyclic substrates,5–9 and
in some cases, in a controlled manner, e.g., those supported by
tris(pyrazolyl)hydroborate5 or b-diketiminate ligands.6
was communicated previously.14 Catalytic examinations of these
molecules are unprecedented.
We are interested in coordination chemistry involving com-
plexes of hybrid chelating ligands.10,11 In particular, a number of
diarylamido phosphine complexes10,12,13 have been prepared and
structurally characterized. In an effort to expand the territory
of this particular ligand set, we have set out to prepare a series
of bidentate chelates bearing variable substituents at both donor
atoms and apply these ligands to explore the coordination chem-
Results and discussion
Ligand synthesis
Scheme 1 illustrates the synthetic protocols to prepare the desired
protio ligand precursors. Such strategies have been successfully
employed for the synthesis of a number of tridentate amido
diphosphine ligands.15 Preparation of H[1a] and H[1b] via the
fluorinated precursors has been described previously,14,16 with the
employment of nucleophilic phosphide reagents. Alternatively,
these molecules may be accessible by bromide intermediates,
which, upon lithiation, serve as nucleophiles to react with
electrophilic chlorodiphenylphosphine or chlorodiisopropylphos-
phine to give H[1a–b] and H[1c–d], respectively. Compounds H[1a]
aDepartment of Chemistry and Center for Nanoscience & Nanotechnology,
National Sun Yat-sen University, Kaohsiung, 80424, Taiwan. E-mail:
lcliang@mail.nsysu.edu.tw
bDepartment of Applied Chemistry, National University of Kaohsiung,
Kaohsiung, 81148, Taiwan
† CCDC reference numbers 773056–773062. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c0dt00327a
8748 | Dalton Trans., 2010, 39, 8748–8758
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Scheme 1 Ligand synthesis.
and H[1b] are colorless crystalline solids whereas H[1c] and H[1d]
are yellow viscous oil. In general, these molecules exhibit solution
Cs symmetry on the NMR timescale. The 31P chemical shifts
of the isopropyl substituted H[1c] and H[1d] (ca. -17 ppm) are
comparatively downfield from those of their phenyl counterparts
H[1a] and H[1b] (ca. -20 ppm). Derivatives similar to H[1c] and
H[1d] appeared recently.17
are thermally stable at elevated temperatures (> 120 ◦C) under an
inert atmosphere. The formation of bis-ligand 4b may be accessed
by treating 2b or 3b with H[1b] upon prolonged heating (100 ◦C),
a reaction rate that is notably slower than that of 3a with H[1a].
In contrast, analogous reactions involving H[1c–d] in attempts
to prepare 4c–d did not proceed at all, even after a prolonged
reaction time (e.g., 120 ◦C, > 4 days), likely reflecting the steric
nature of these ligands be more significant than that of phenyl
substituted 1a–b. Nevertheless, 4d may be isolated by metathetical
route (vide infra).
Given the fact that lithium amides are useful starting materials
for metathetical reactions with metal halides, we turned our
attention to prepare lithium complexes of 1. The preparation of
5a–b was reported previously.14,19 Analogously, deprotonation of
H[1c–d] with n-BuLi in ethereal solutions at -35 ◦C produced 5c–d.
Both 5c and 5d were isolated as pale yellow crystals; the former
contains two equivalents of coordinated THF whereas the latter is
a DME adduct. We note that, after multiple attempts, crystalliza-
tion of lithium complex of 1d from THF was not successful; the
involvement of DME facilitates crystallization and purification.
In addition to zinc alkyls, zinc alkoxides are also intriguing
as both are potential initiators for catalytic polymerization of
heterocycles. Our initial plans to prepare zinc alkoxides of 1 involve
alcoholysis of zinc alkyls 2–3. Unfortunately, these reactions led
undesirably to protonation on the amido nitrogen donor of 1,
highlighting perhaps its higher basicity than alkyl ligands in
2–3. These results, however, are consistent with their moisture
sensitivity as aforementioned.
Synthesis of zinc complexes
Scheme 2 summarizes the preparation of corresponding zinc
complexes. Treatment of H[1a] with one equivalent of ZnMe2 in
diethyl ether at -35 ◦C led to the formation of a mixture containing
[1a]ZnMe (2a) and [1a]2Zn (4a) in a 7 : 3 ratio as evidenced by
1
1H and 31P{ H} NMR. Analogous reactions employing ZnEt2,
however, produced cleanly [1a]ZnEt (3a); no 4a was found in
the reaction aliquots. These results are phenomenal as 3a is an
adjacent higher homologue of 2a. The concomitant formation
of homoleptic 4a in attempts to prepare 2a thus highlights the
insufficient steric size of the alkyl ligand in 2a as compared to that
in 3a. Complex 4a may be alternatively prepared in quantitative
yield from reactions of ZnMe2 with two equivalents of H[1a] at
-35 ◦C or 3a with H[1a] upon mild heating (60 ◦C).
With lithium complexes 5a–d at hand, we attempted to prepare
zinc chloride or zinc acetate complexes of 1; the former may in
turn lead to zinc alkoxides by metathetical reactions. Unsatisfac-
torily, the bis-ligand complexes 4 were the only spectroscopically
decipherable or isolable products, regardless of the stoichiometry
of 5 and ZnX2 (X = Cl, OAc) employed (Scheme 2); no presumed
[1]ZnCl or [1]ZnOAc (or their corresponding dimers) was found.
Though less sterically congested than 4d, complex 4c has thus far
been elusive as several approaches that we had examined gave a
mixture of products (31P NMR evidence), from which isolation or
purification was not successful. It is interesting to note that the
facile formation of 4 by metathetical reactions is in sharp contrast
to what is found for slow alcoholysis rates involving H[1] and
2–3, particularly H[1b] and H[1d]. Such discrepancy in reaction
rates thus implies higher reactivity of [1]ZnX (X = Cl, OAc) than
[1]ZnR (R = Me, Et) under the conditions investigated.
Scheme 2 Synthesis of zinc complexes.
In contrast to H[1a], H[1b–d] reacts with one equivalent
of ZnMe2 to generate cleanly the corresponding zinc methyl
complexes 2b–d, highlighting the sufficient steric protection from
the latter ligands. Analogous reactions involving ZnEt2 gave
3b–d quantitatively. Remarkably, these monomeric, three-
coordinate zinc alkyls 2–3 are not associated with coordinating
solvents such as THF or Et2O (NMR evidence), in spite of their
coordinatively unsaturated nature. It should be noted that three-
coordinate zinc complexes that do not bind coordinating solvent
molecules are extremely rare,18 particularly for those bearing
small alkyls. Compounds 2–3 are extremely sensitive to moisture,
It has been shown that metal complexes of anionic ligands may
be synthesized by in situ preparation of protio ligand adducts
of metal halides followed by deprotonation with appropriate
bases.20–22 We attempted to prepare [1]ZnCl based on this strategy.
Treatment of ZnCl2 with one equivalent of H[1c] in THF at room
temperature produced high yield of phosphorus-bound adduct
1
producing exclusively H[1] as evidenced by 31P{ H} NMR, but
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Scheme 3 Alternative strategy for the synthesis of zinc complexes.
˚
{H[1c]ZnCl(m-Cl)}2 (6c, Scheme 3). This compound is thermally
stable; attempts to eliminate hydrochloride by thermolysis were
not successful (80 ◦C, 3 days). Surprisingly, addition of two
equivalents of n-BuLi to a THF solution of the dimeric 6c at
-35 ◦C did not lead to deprotonation to eliminate butane. Instead,
alkylation occurred to afford [1c]Zn(n-Bu) (7c) in high yield and
presumably produce LiCl and HCl concurrently. Employment of
non-alkylating bases such as NEt3 gave H[1c] and [ZnCl2(NEt3)]2
via Lewis base substitution (NMR evidence). The presumed
[1c]ZnCl remains elusive from these reactions.
Table 1 Selected bond distances (A) for 2c–d, 3b–c, 4b, and 4d–e
Com-
pound Zn–N
Zn–P
Zn–C
Reference
2c
2d
3b
3c
4b
4d
4ea
1.951(3)
2.4036(11)
2.3897(14)
2.4450(14)
2.3956(7)
1.963(4) This work
1.941(5) This work
1.956(5) 14
1.962(3) This work
14
1.954(4)
1.911(4)
1.953(2)
1.971(5), 1.974(5) 2.4545(19), 2.4387(19)
2.015(4), 2.014(3) 2.4333(11), 2.4319(12)
This work
27
1.9685(15),
1.9685(15)
2.3720(13), 2.3720(13)
a Bis(N-(2-diisopropylphosphinophenyl)anilide)zinc.
NMR studies
All NMR spectroscopic data of alkyls 2–3 and 7c are consistent
with solution Cs symmetry. Though 2a was not isolable due to
concomitant formation of 4a, its identity was deduced by 1H and
1
quartet resonance whereas 7Li{ H} NMR shows a doublet signal
(Fig. S1, see ESI†), consistent with the coordination of the
phosphorus donor in 1 to a quadrupolar 7Li atom (I = 3/2, natural
1
31P{ H} NMR spectra of product mixtures in comparison with
1
those of 2b–d and 4a, respectively. Interestingly, the 31P chemical
shifts of ca. -28 ppm for 2a–b and 3a–b are relatively upfield from
those of H[1a–b] whereas the signals for 2c–d, 3c–d, and 7c (ca.
-14 ppm) are downfield shifted in comparison with H[1c–d]. This
discrepancy likely reflects electronic identities of the substituents
abundance 92.6%). The JPLi values range from 34 (5a) to 49 Hz
(5d). In the cases of 5a and 5c, lowering temperature to ≤ -20 ◦C is
necessary for P–Li coupling observation whereas the multiplicity
for 5b and 5d is detected at room temperature. In contrast to those
observed for zinc complexes 2–4 and 7c, the 31P chemical shifts
of 5 are all relatively downfield from their corresponding protio
ligands regardless of the substituents at the phosphorus donors.
at the phosphorus donors in 1. A similar upfield change in the 31
P
chemical shift was also observed for (2,6-tBu2C6H3O)2Zn(PCy3)
(-2.1 ppm)23 and [(m-Cl)(ZnLCl)2][ClO4] (-3.2 ppm, L = N-
(diphenylphosphinopropyl)-1,4,7-triazacyclononane)24 as com-
pared to their corresponding free phosphines. Consistent with the
coordination of the phosphorus donors, the Ha and Ca atoms in
these alkyl complexes exhibit a diagnostic coupling where resolved,
e.g., 3JPHa = 4.2 Hz for 2c and 2JPCa = 37 Hz for 3d, in the 1H and
The identity of coordinating solvents in 5 appears to affect the 31
P
chemical shifts more significantly (5a–c: ca. -11 ppm; 5d: -7 ppm)
than that of the phosphorus substituents. The H and 13C{ H}
NMR data are consistent with solution Cs symmetry for these
molecules.
1
1
The 31P{ H} NMR spectrum of complex 6c exhibits a diagnostic
1
1
13C{ H} NMR spectra. The isopropylmethyl groups in 2–3 and
downfield shift from that of its protio ligand 1c. This signal,
detected at -8 ppm, is relatively broad (Dv1/2 = 65 Hz) as compared
to the others reported in this study. Such broadening is ascribable
to a dynamic equilibrium involving association/dissociation of the
bridging chloride atoms. The absolute structure was elucidated by
a single-crystal diffraction study.
7c, where appropriate, are all diastereotopic as evidenced by the
1
1H and 13C{ H} NMR spectra, implying steric congestion of these
molecules.
The homoleptic 4a, 4b, and 4d display solution C2 symmetry
on the NMR timescale; no internal symmetry is found within
each amido phosphine ligand. Similar to what has been described
for alkyls 2–3, the phosphorus donors in 4a–b resonate relatively
upfield from their protio ligands whereas those in 4d resonate
downfield from H[1d]. Coincidentally, the 31P chemical shifts of
4a and 4d are comparable to those of their corresponding alkyl
X-Ray crystallographic studies†
Three-coordinate zinc complexes of phosphine are extremely
rare.23,25,26 Yellow crystals of alkyls 2c and 3c suitable for X-
ray diffraction analysis were grown from a concentrated diethyl
ether solution at -35 ◦C whereas those of 2d from n-hexane. The
homoleptic 4d crystallizes from n-pentane solutions. Molecular
structures are depicted in Fig. 1; selected bond distances and angles
are summarized in Tables 1 and 2, respectively, in comparison with
corresponding values of previously established 3b,14 4b,14 and a
closely related bis(N-(2-diisopropylphosphinophenyl)anilide)zinc
(4e).27
1
counterparts 2–3. In the H NMR spectrum of 4d, one of the
isopropylmethyl groups associated with the phosphorus donors
resonates unusually upfield (0.34 ppm, doublet of doublets) as
compared to other derivatives of 1d. We ascribe this phenomenon
to ring current effect arising from adjacent N-aryl substituents
(X-ray evidence, vide infra).
The most diagnostic NMR data for lithium complexes 5 concern
1
perhaps the P–Li bonding; 31P{ H} NMR exhibits a 1 : 1 : 1 : 1
8750 | Dalton Trans., 2010, 39, 8748–8758
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Fig. 1 Molecular structures of 2c–d, 3b–c, and 4d with thermal ellipsoids drawn at the 35% probability level. All hydrogen atoms in 2c–d, 3b–c, 4d and
methyl groups in 4d are omitted for clarity.
Table 2 Selected bond angles (◦) for 2c–d, 3b–c, 4b, and 4d–e
Compound N–Zn–Pa
Reference
N–aryl ring (dihedral angle of 79.24◦ with mean coordination
plane), the Cb atom in 3c is displaced from the mean coordination
N–Zn–C
P–Zn–C
˚
plane by 0.794 A.
The core geometry for bis-ligated 4b and 4d is best described
as distorted tetrahedral. Consistent with the increased steric
repulsion between the substituents at all donor atoms, the N–Zn–
P bite angles in these homoleptic complexes are generally sharper
than those of three-coordinate alkyls, particularly 4d (average
82.8◦), which is apparently the most sterically congested molecule
in this study. In agreement with this steric argument, these bite
angles are even smaller than those of bis-ligated Zn[2-(Ph2P)-
6-(Me3Si)C6H3S]2 (average 87.6◦)28 though the Zn–S distances
2c
2d
3b
3c
4b
4d
4eb
85.46(9)
85.73(12)
85.04(12)
84.96(6)
84.24(15), 83.15(15)
82.78(10), 82.85(10)
85.72(4), 85.72(4)
135.70(17) 138.69(14) This work
130.1(2) 143.9(2) This work
140.55(19) 134.22(16) 14
131.03(10) 143.81(9) This work
14
This work
27
a Bite angles. b Bis(N-(2-diisopropylphosphinophenyl)anilide)zinc.
˚
(average 2.279 A) are significantly longer. In 4d, two methyl groups
The Zn–N, Zn–P, and Zn–C distances are all unexceptional. The
Zn–N distances in three-coordinate 2c–d and 3b–c do not change
much with different aryl substituents, nor do Zn–P lengths, though
that associated with phenyl substituted phosphine (3b) is slightly
longer than those of isopropyl counterparts (2c–d and 3c), likely
reflecting their distinct electronic nature. A similar phenomenon
is also found for four-coordinate bis-ligand derivatives (4b versus
4d and 4e).
(C2 and C26 in Fig. S2, see ESI†) in PiPr2 lie right above the
i
N-C6H3 Pr2-2,6 rings, leading to the usually upfield resonance
observed in the 1H NMR spectrum.
Yellow crystals of 5c and 5d were grown from a concentrated
pentane and diethyl ether solution, respectively, at -35 ◦C. Molec-
ular structures are depicted in Fig. 2; selected bond distances
and angles are summarized in Table 3, in comparison with those
of 5a.19 The geometry at lithium is distorted tetrahedral; the
N–Li–P/O–Li–O dihedral angle decreases following the order
of 5a < 5c < 5d. The Li–N, Li–P, and Li–O distances are all
unexceptional. Reminiscent of what is found for zinc derivatives
(vide supra), the Li–E (E = N, P, O) distances do not change
The zinc atom in 2c–d and 3b–c lies virtually on the mean N–
phenylene–P plane with a slight deviation whereas that in 4b and 4d
˚
is displaced significantly by 0.69 and 0.88 A (average), respectively.
With relatively smaller sterics, the corresponding deviation of
27
˚
0.32 A (average) for 4e is much less.
In three-coordinate 2c–d and 3b–c, the N–Zn–P bite angles
are all similar; the sum of the angles about Zn is close to 360◦,
indicating a trigonal planar geometry at zinc for these molecules.
Interestingly, the P–Zn–C angles associated with isopropyl sub-
stituted phosphines (i.e., 2c–d and 3c) are all wider than N–
Zn–C whereas that with phenyl substituents (i.e., 3b) is sharper.
These results likely reflect the steric demand of substituents at
i
these heteroatoms following the order of PiPr2 > N(C6H3 Pr2-
2,6) > PPh2. Consistently, the Cb atom in both 3b and 3c, though
tilted in different directions, is disposed towards the less sterically
congested side with the Zn–Ca–Cb angle of 3b (115.4(4)◦) and 3c
(113.8(2)◦) being both larger than what is anticipated for an sp3
carbon atom. To accommodate the steric repulsion with the tilted
Fig. 2 Molecular structures of 5c–d with thermal ellipsoids drawn at the
35% probability level. All hydrogen atoms in 5c–d and isopropylmethyl
groups in 5d are omitted for clarity.
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◦
˚
Table 3 Selected bond distances (A), bond angles ( ), and dihedral angles
(◦) for 5a, 5c, and 5d
Compound 5aa
5c
5d
Li–N
Li–P
1.990(5)
2.620(5)
1.957(9)
2.573(8)
1.958(10)
2.547(9)
Li–O
1.921(5), 1.942(5) 2.003(9), 1.959(8) 2.026(10), 1.957(10)
N–Li–P
O–Li–O
N–Li–
P/O–Li–O
76.63(17)
99.8(2)
86.89
81.6(3)
97.6(4)
85.93
82.6(3)
82.1(4)
75.10
a Reference 19.
much with different substituents, though Li–PiPr2 lengths (5c–d)
are slightly shorter than Li–PPh2 (5a), a result ascribable to
different electronic properties of these phosphorus substituents.
A similar phenomenon is also found for tridentate PNP analogues
that carry distinct aliphatic and aromatic groups at phosphorus
donors.15,29,30 Consistent with the trend in Li–P distances, the N–
Li–P bite angles of 5c–d are wider than that of 5a. The O–Li–O
angle of 5d is notably sharper than those of 5a and 5c due to
chelation of the bidentate DME.
Fig. 3 Molecular structure of 6c with thermal ellipsoids drawn at the
35% probability level. All hydrogen atoms are omitted for clarity. Selected
◦
˚
bond distances (A) and angles ( ): Zn(1)–Cl(2) 2.190(2), Zn(1)–Cl(1)
2.304(2), Zn(1)–P(1) 2.356(2), Zn(1)–Cl(1A) 2.573(2), Cl(2)–Zn(1)–Cl(1)
114.32(9), Cl(2)–Zn(1)–P(1) 125.27(9), Cl(1)–Zn(1)–P(1) 116.16(9),
Cl(2)–Zn(1)–Cl(1A) 105.28(9), Cl(1)–Zn(1)–Cl(1A) 88.51(7), P(1)–Zn(1)–
Cl(1A) 95.83(8), Zn(1)–Cl(1)–Zn(1A) 91.49(7).
(Ha at 1.86 ppm) to hydroxyl methylene group (Hf, 3.75 ppm)
equals 1.5, consistent with the initiation step occurring with
insertion of the coordinated monomer into the Zn–Me bond.
Subsequent cleavage of the acyl–oxygen bond then ring-opens
the monomer and generates a reactive zinc alkoxide intermediate
for chain propagation. A coordination–insertion mechanism is
thus likely operating in this system. Upon acidic work-up, the
zinc alkoxide chain end is protonated to give the hydroxyl group.
Gel permeation chromatography (GPC) analyses show that the
(corrected)33,34 number averaged molecular weights (Mn) of PCLs
are consistently higher than the corresponding theoretical values,
implying possibly only a portion of zinc complexes participates
in catalysis. The relatively low polydispersity index (PDI) of ca.
1.5 indicates reasonably narrow molecular weight distributions,
suggesting the identity of catalytically active species be nearly
uniform, though not single-site.5,6 The PDIs of ca. 2 found for
3a–b (entries 1 and 3), however, reflect that transesterification
processes are likely taking place. Interestingly, the found Mn of
PCLs is approximately proportional to the monomer-to-catalyst
ratio or the anticipated Mn (entries 5–8, Fig. S4 and S5, see ESI†),
indicating propagating chains grow in a reasonably controlled
manner.
Pale yellow prisms of 6c were grown from a concentrated
diethyl ether solution at -35 ◦C. This chloride bridged dimer is Ci
31
symmetric (Fig. 3); its core is isostructural to {[Et3P]ZnI(m-I)}2
and {[(Me3Si)3P]ZnI(m-I)}2.32 The Zn–Cl and Zn–P distances are
unexceptional.
Catalysis
ROP of e-CL by the derived zinc complexes was examined. The
homoleptic complexes 4 are virtually inactive; only a negligible
amount of products was obtained. In contrast, alkyls 2–3 are all
active. The high propensity of amide protonation for 2–3 (vide
supra) precludes catalysis investigation of these molecules in the
presence of alcohols. Table 4 summarizes polymerization results
and characterization data of the derived poly(e-caprolactone)
(PCL). In general, these zinc catalysts are quite active (ca. 90% to
quantitative conversion) under the conditions employed, except
3a due likely to relatively insufficient steric protection imposed
by 1a. Fig. S3 (see ESI†) depicts a representative 1H NMR
spectrum of PCL prepared by ROP with catalytic 2c. End group
analysis shows that the integral ratio of keto methyl group
Table 4 Polymerization of e-CL by catalysts 2 and 3a
Entry
[e-CL]0/[Zn]0
Zn
Conv (%)b
Mn (calc, kg mol-1)c
Mn (exp, kg mol-1)d
Corrected Mn (exp, kg mol-1)e
PDId
1
2
3
4
5
6
7
8
152
150
152
150
25
3a
2b
3b
2c
3c
3c
3c
3c
2d
3d
69
92
100
97
95
97
95
87
95
98
12.0
15.8
17.3
16.6
2.7
47.2
44.1
57.2
70.1
34.4
58.7
78.5
88.5
77.5
53.1
26.4
24.7
32.0
39.3
19.3
32.9
44.0
49.6
43.4
29.7
1.79
1.21
1.95
1.52
1.45
1.55
1.65
1.53
1.41
1.53
75
8.3
100
150
150
150
10.8
14.9
16.3
16.8
9
10
a Conditions: [Zn]0 = 2.0 mM, toluene, 80 ◦C, 2 h; these parameters were not optimized. b Determined by H NMR analysis. c Calculated from fw of
e-CL ¥ ([e-CL]0/[Zn]0) ¥ conversion, assuming one propagation chain per zinc atom. d Measured by GPC in THF, calibrated with polystyrene standards.
e Multiplied by a factor of 0.56.33,34
1
8752 | Dalton Trans., 2010, 39, 8748–8758
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hydrogen atoms were refined anisotropically. Hydrogen atoms
were placed in calculated positions. The structure of 4d contains
disordered pentane molecules. Attempts to obtain a suitable
disorder model failed. The SQUEEZE procedure of Platon
program36 was used to obtain a new set of F2 (hkl) values without
the contribution of solvent molecules, leading to the presence of
significant voids in this structure. The refinement reduced R1 value
to 0.0599.
Conclusions
We have prepared a series of zinc and lithium complexes supported
by bidentate diarylamido phosphine ligands and characterized
their solution and solid-state structures by means of NMR spec-
troscopy and X-ray crystallography. Of interest is the successful
isolation of monomeric, coordinatively unsaturated alkyls 2–3 and
7c that do not adopt strong coordinating solvents. Attempts to
prepare the corresponding zinc alkoxide derivatives with numerous
approaches, however, were not successful. Zinc chlorides and
alkoxides supported by these amido phosphine ligands remain
elusive in this study. In contrast, the homoleptic complexes 4
appears to be more thermally stable, even with substantial steric
pressure intramolecularly (particularly 4d) as evidenced by X-ray
crystallographic data. On the basis of the NMR and X-ray studies,
in combination with the synthetic results, the steric size of these
amido phosphine ligands thus follows the order of 1a < 1b <
1c < 1d. Interestingly, zinc alkyls 2–3 are all active initiators for
catalytic ROP of e-CL, producing PCLs with molecular weights
and molecular weight distributions in a reasonably controlled
manner.
Materials
Compounds N-(2-fluorophenyl)-2,6-dimethylaniline,16 N-(2-
fluorophenyl)-2,6-diisopropylaniline,14 2b,14 3b,14 4b,14 5a,19 and
5b14 were prepared according to literature procedures.
Synthesis of N-(2-bromophenyl)-2,6-dimethylaniline
A Schlenk flask was charged with 1-bromo-2-iodobenzene
(10.08 g, 35.64 mmol), 2,6-dimethylaniline (4.32 g, 35.64 mmol),
Pd(OAc)2 (40 mg, 0.18 mmol, 0.5% equiv.), bis[2-(diphenyl-
phosphino)phenyl]ether (DPEphos, 144 mg, 0.27 mmol,
0.75% equiv.), sodium tert-butoxide (4.80 g, 49.9 mmol, 1.4 equiv.),
and toluene (70 mL) under nitrogen. The flask was sealed with
a rubber septum and heated to 95 ◦C with stirring for 3 d.
After being cooled to room temperature, the reaction mixture was
evaporated to dryness under reduced pressure. The solid residue
was dissolved in deionized water (70 mL) and CH2Cl2 (100 mL).
The organic portion was separated from the aqueous layer, which
was further extracted with dichloromethane (40 mL ¥ 2). The
combined organic solution was dried over MgSO4 and filtered. The
solvent was removed in vacuo to yield brown viscous oil, which was
subjected to flash column chromatography on Al2O3 using Et2O as
the eluant. The first band (pale yellow) was collected and solvent
was removed in vacuo, affording the product as pale yellow oil,
which solidified upon standing at room temperature; yield 9.72 g
(99%). 1H NMR (CDCl3, 500 MHz) d 7.53 (dd, 1H, Ar), 7.18 (m,
3H, Ar), 7.06 (t, 1H, Ar), 6.64 (td, 1H, Ar), 6.21 (dd, 1H, Ar),
Experimental
General procedures
Unless otherwise specified, all experiments were performed under
nitrogen using standard Schlenk or glovebox techniques. All
solvents were reagent grade or better and purified by standard
methods. All other chemicals were obtained from commercial
vendors and used as received. The NMR spectra were recorded
on Varian or Bruker instruments. Chemical shifts (d) are listed as
parts per million downfield from tetramethylsilane, and coupling
constants (J) are in hertz. 1H NMR spectra are referenced using the
residual solvent peak at d 7.16 for C6D6 and d 7.27 for CDCl3. 13
C
NMR spectra are referenced using the internal solvent peak at d
128.4 for C6D6 and d 77.2 for CDCl3. The assignment of the carbon
atoms for all new compounds is based on the DEPT 13C NMR
spectroscopy. 31P and 7Li NMR spectra are referenced externally
using 85% H3PO4 at d 0 and LiCl in D2O at d 0, respectively.
Routine coupling constants are not listed. All NMR spectra were
recorded at room temperature in specified solvents. Elemental
analysis was performed on a Heraeus CHN-O Rapid analyzer.
With multiple attempts, we were unable to obtain satisfactory
analysis for some metal complexes due to their extreme moisture-
sensitivity.
GPC analyses were carried out on a Waters instrument equipped
with two Styragel HR columns in series and a 2414 RI detector.
HPLC grade THF was supplied at a constant flow rate of
1.0 mL min-1 with a 1515 Isocratic HPLC Pump. Molecular
weights (Mn and Mw) were determined by interpolation from
calibration plots established with polystyrene standards.
1
5.75 (br s, 1H, NH), 2.25 (d, 6H, CH3). 13C{ H} NMR (CDCl3,
125.5 MHz) d 143.3 (s, C), 137.5 (s, C), 136.5 (s, C), 132.4 (s, CH),
128.5 (s, CH), 128.3 (s, CH), 126.5 (s, CH), 118.6 (s, CH), 112.5
(s, CH), 109.5 (s, C), 18.1 (s, CH3). Anal. Calcd for C14H14BrN: C,
60.89; H, 5.11; N, 5.07. Found: C, 61.19; H, 5.47; N, 5.15.
Synthesis of N-(2-bromophenyl)-2,6-diisopropylaniline
A Schlenk flask was charged with 1-bromo-2-iodobenzene
(1.00 g, 3.54 mmol), 2,6-diisopropylaniline (627 mg, 3.54 mmol),
Pd(OAc)2 (4 mg, 0.018 mmol, 0.5% equiv.), bis[2-(diphenyl-
phosphino)phenyl]ether (DPEphos, 14 mg, 0.027 mmol,
0.75% equiv.), sodium tert-butoxide (475 mg, 4.95 mmol,
1.4 equiv.), and toluene (25 mL) under nitrogen. The flask was
sealed with a rubber septum and heated to 95 ◦C with stirring
for 7 d. After being cooled to room temperature, the reaction
mixture was evaporated to dryness under reduced pressure. The
solid residue was dissolved in deionized water (25 mL) and CH2Cl2
(25 mL). The organic portion was separated from the aqueous
layer, which was further extracted with dichloromethane (10 mL ¥
2). The combined organic solution was dried over MgSO4 and
filtered. The solvent was removed in vacuo to yield brown viscous
oil, which was subjected to flash column chromatography on Al2O3
X-Ray crystallography.35
Data were collected on a Bruker-Nonius Kappa CCD diffrac-
tometer with graphite monochromated Mo-Ka radiation (l =
˚
0.7107 A). Structures were solved by direct methods and refined
by full matrix least squares procedures against F2 using maXus or
WinGX crystallographic software package. All full-weight non-
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using Et2O as the eluent. The first band (pale yellow) was collected
and solvent was removed in vacuo, affording the product as pale
yellow oil; yield 1.10 g (94%). 1H NMR (CDCl3, 500 MHz) d 7.39
(dd, 1H, Ar), 7.24 (m, 1H, Ar), 7.16 (m, 2H, Ar), 6.91 (td, 1H,
Ar), 6.48 (td, 1H, Ar), 6.07 (dd, 1H, Ar), 5.61 (s, 1H, NH), 3.02
(septet, 2H, CHMe2), 1.10 (d, 6H, CHMe2), 1.03 (d, 6H, CHMe2).
mixture was cooled to -35 ◦C and chlorodiisopropylphosphine
(1.11 g, 7.24 mmol) was added. The reaction solution was stirred
at room temperature overnight and quenched with degassed deion-
ized water (10 mL). The product was extracted with deoxygenated
dichloromethane (50 mL). The organic solution was separated
from the aqueous portion, from which the product was further
extracted with dichloromethane (15 mL ¥ 2). The combined
organic solution was dried over MgSO4 and filtered. All volatiles
were removed in vacuo, affording the product as yellow viscous oil;
1
13C{ H} NMR (CDCl3, 125.5 MHz) d 147.7 (s, C), 144.9 (s, C),
134.6 (s, C), 132.3 (s, CH), 128.2 (s, CH), 127.8 (s, CH), 123.9 (s,
CH), 118.3 (s, CH), 112.6 (s, CH), 108.8 (s, C), 28.3 (s, CHMe2),
24.6 (s, CHMe2), 23.0 (s, CHMe2).
1
yield 2.17 g (96%). H NMR (C6D6, 500 MHz) d 7.22 (ddd, 1H,
Ar), 7.07 (d, 1H, JHP = 12, NH), 7.01 (s, 3H, Ar), 6.96 (td, 1H,
Ar), 6.70 (td, 1H, Ar), 6.26 (dd, 1H, Ar), 2.17 (s, 6H, CH3), 2.01
(septet of doublets, 2H, PCHMe2), 1.14 (dd, 6H, PCHMe2), 0.98
Synthesis of H[1a]
To a solution of N-(2-bromophenyl)-2,6-dimethylaniline (100 mg,
0.36 mmol) in diethyl ether (6 mL) at -35 ◦C was added dropwise
n-BuLi (0.29 mL, 2.5 M in hexane, 0.72 mmol, 2 equiv.). The
reaction solution was naturally warmed to room temperature and
stirred for 1 h, providing a pale yellow solution along with a
significant amount of off-white precipitate. The reaction mixture
was cooled to -35 ◦C again and chlorodiphenylphosphine (80 mg,
0.36 mmol) was added. The reaction mixture was stirred at room
temperature for 12 h. Degassed deionized water (6 mL) and diethyl
ether (6 mL) were added sequentially. The diethyl ether portion was
separated from the aqueous solution, which was further extracted
with diethyl ether (3 mL ¥ 2). The diethyl ether solutions were
combined, dried over MgSO4, and evaporated to dryness under
reduced pressure. The yellow oil thus obtained was dissolved in
degassed methanol (4 mL) and cooled to -40 ◦C to give the
product as an off-white crystalline solid; yield 103 mg (74%).
The NMR spectroscopic data are all identical to those reported
previously.16
1
(dd, 6H, PCHMe2). 31P{ H} NMR (C6D6, 202.31 MHz) d -17.41.
1
13C{ H} NMR (C6D6, 125.5 MHz) d 152.9 (d, JCP = 19.2, C),
139.8 (d, JCP = 2.4, C), 137.2 (s, C), 133.8 (d, JCP = 2.8, CH), 131.0
(s, CH), 129.2 (s, CH), 126.6 (s, CH), 117.9 (s, CH), 117.3 (d, JCP
=
1
13.7, C), 111.6 (d, JCP = 2.8, CH), 24.1 (d, JCP = 9.7, CHMe2),
20.8 (d, 2JCP = 18.7, CHMe2), 19.5 (d, 2JCP = 8.7, CHMe2), 18.9
(s, ArMe). Anal. Calcd for C20H28NP: C, 76.63; H, 9.01; N, 4.47.
Found: C, 76.66; H, 9.28; N, 4.18.
Synthesis of H[1d]
To
a solution of N-(2-bromophenyl)-2,6-diisopropylaniline
(208 mg, 0.63 mmol) in diethyl ether (6 mL) at -35 ◦C was
added n-BuLi (0.8 mL, 1.6 M in hexane, 1.28 mmol, 2 equiv.).
The reaction solution was naturally warmed to room temperature
with stirring. After being stirred at room temperature for 1 h,
the reaction mixture was cooled to -35 ◦C and chlorodiisopropy-
lphosphine (0.1 mL, 0.63 mmol) was added. The reaction solution
was stirred at room temperature overnight and quenched with
degassed deionized water (10 mL). The product was extracted with
deoxygenated dichloromethane (10 mL). The organic solution was
separated from the aqueous portion, from which the product was
further extracted with dichloromethane (5 mL ¥ 2). The combined
organic solution was dried over MgSO4 and filtered. All volatiles
were removed in vacuo, affording the product as yellow viscous
Synthesis of H[1b]
To
a solution of N-(2-bromophenyl)-2,6-diisopropylaniline
(100 mg, 0.30 mmol) in diethyl ether (6 mL) at -35 ◦C was added
dropwise n-BuLi (0.24 mL, 2.5 M in hexane, 0.60 mmol, 2 equiv.).
The reaction solution was naturally warmed to room temperature
and stirred for 1 h, providing a pale yellow solution along with a
significant amount of off-white precipitate. The reaction mixture
was cooled to -35 ◦C again and chlorodiphenylphosphine (66 mg,
0.30 mmol) was added. The reaction mixture was stirred at room
temperature for 12 h. Degassed deionized water (6 mL) and diethyl
ether (6 mL) were added sequentially. The diethyl ether portion was
separated from the aqueous solution, which was further extracted
with diethyl ether (3 mL ¥ 2). The diethyl ether solutions were
combined, dried over MgSO4, and evaporated to dryness under
reduced pressure. The yellow oil thus obtained was dissolved
in degassed ethanol (6 mL) and cooled to -40 ◦C to give the
product as an off-white crystalline solid; yield 115 mg (87%).
The NMR spectroscopic data are all identical to those reported
previously.14
1
oil; yield 210 mg (91%). H NMR (C6D6, 500 MHz) d 7.24 (d,
1H, JHP = 8.5, NH), 7.20 (m, 3H, Ar), 7.15 (t, 1H, Ar), 6.96 (td,
1H, Ar), 6.67 (td, 1H, Ar), 6.30 (ddd, 1H, Ar), 3.36 (septet, 2H,
ArCHMe2), 2.02 (septet of doublets, 2H, PCHMe2), 1.19 (d, 6H,
ArCHMe2), 1.16 (dd, 6H, PCHMe2), 1.13 (d, 6H, ArCHMe2),
1
1.10 (dd, 6H, PCHMe2). 31P{ H} NMR (C6D6, 202.31 MHz) d
1
-17.15. 13C{ H} NMR (C6D6, 125.5 MHz) d 154.7 (d, JCP = 19.2,
C), 148.2 (s, C), 137.3 (d, JCP = 2.8, C), 133.7 (d, JCP = 3.3, CH),
131.0 (s, CH), 128.0 (s, CH), 124.6 (s, CH), 117.8 (s, CH), 116.7 (d,
JCP = 12.8, C), 111.9 (d, JCP = 2.8, CH), 29.3 (s, ArCHMe2), 25.3
(s, ArCHMe2), 24.1 (d, 1JCP = 9.2, PCHMe2), 23.4 (s, ArCHMe2),
20.7 (d, 2JCP = 18.7, PCHMe2), 19.4 (d, 2JCP = 8.7, PCHMe2).
Synthesis of 2a
Synthesis of H[1c]
To a diethyl ether solution (3 mL) of ZnCl2 (68 mg, 0.5 mmol) at
-35 ◦C was added MeMgCl (0.33 mL, 3.0 M in THF, 0.99 mmol).
The reaction mixture was naturally warmed and stirred at room
temperature overnight. The solution was chilled to -35 ◦C again
and a pre-chilled solution of H[1a] (191 mg, 0.5 mmol) in
diethyl ether (5 mL) at -35 ◦C was added. After being stirred
To a solution of N-(2-bromophenyl)-2,6-dimethylaniline (2.00 g,
7.24 mmol) in diethyl ether (40 mL) at -35 ◦C was added n-BuLi
(9.05 mL, 1.6 M in hexane, 14.48 mmol, 2 equiv.). The reaction
solution was naturally warmed to room temperature with stirring.
After being stirred at room temperature for 1 h, the reaction
8754 | Dalton Trans., 2010, 39, 8748–8758
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at room temperature overnight, the reaction mixture was stripped
to dryness in vacuo. Benzene (16 mL) was added. The benzene
solution was filtered through a pad of Celite which was further
washed with benzene (2 mL ¥ 2) until the washings became
colorless. The filtrates were combined and evaporated to dryness
under reduced pressure to afford a yellow solid that contained 2a
Synthesis of 3a
Solid H[1a] (200 mg, 0.52 mmol) was dissolved in diethyl ether
(5 mL) and cooled to -35 ◦C. To this was added a solution
of ZnEt2 (0.52 mL, 1.0 M in hexane, 0.52 mmol). The reaction
solution was naturally warmed to room temperature and stirred
overnight. After being filtered through a pad of Celite, the solution
1
and 4a in a ratio of 7 : 3; yield 131 mg (57%). H NMR (C6D6,
◦
was concentrated to ca. 3 mL and cooled to -35 C to afford a
200 NMR) d 7.42 (m, 5H, Ar), 7.20 (m, 3H, Ar), 7.05 (m, 7H,
Ar), 6.41 (t, 1H, Ar), 6.25 (t, 1H, Ar), 2.27 (s, 6H, ArCH3),
colorless, crystalline solid, which was isolated from the solution
and dried in vacuo; yield 172 mg (69%). 1H NMR (C6D6, 500 MHz)
d 7.36–7.40 (m, 4H, Ar), 7.14 (m, 2H, Ar), 6.94–7.08 (m, 9H, Ar),
6.40 (t, 1H, Ar), 6.27 (t, 1H, Ar), 2.23 (s, 6H, Me), 1.35 (t, 3H,
1
-0.27 (br s, 3H, ZnCH3). 31P{ H} NMR (C6D6, 202.5 MHz)
d -29.50.
ZnCH2CH3), 0.70 (q, 2H, ZnCH2CH3). 31P{ H} NMR (C6D6,
1
202.5 Hz) d -28.93. 13C NMR (C6D6, 125.5 MHz) d 161.6 (JCP
=
Synthesis of 2c
18.3), 148.9 (JCP = 6.9), 135.2 (JCP = 11.4, CH), 134.4 (CH),
133.9 (JCP = 15.1, CH), 130.8 (JCP = 1.8, CH), 130.8 (JCP = 29.7),
To a solution of H[1c] (100 mg, 0.32 mmol) in diethyl ether
(6 mL) at -35 ◦C was added ZnMe2 (0.16 mL, 2 M in toluene,
0.32 mmol). The reaction mixture was naturally warmed to room
temperature and stirred overnight. The diethyl ether solution was
filtered through a pad of Celite, which was further washed with
diethyl ether (2 mL ¥ 2). The diethyl ether filtrate and washings
were combined and evaporated to dryness under reduced pressure.
The yellow solid thus obtained was washed with pentane (1 mL x 2)
and dried in vacuo; yield 119 mg (95%). Yellow crystals suitable for
X-ray diffraction analysis were grown from a concentrated diethyl
129.7 (JCP = 9.7, CH), 129.6 (CH), 124.4 (CH), 114.9 (JCP
=
5.4, CH), 113.1 (JCP = 5.0, CH), 110.3, 109.9, 19.2 (C6H3Me2),
13.0 (ZnCH2CH3), 2.0 (ZnCH2). Anal. Calcd. for C28H28NPZn:
C, 70.80; H, 5.95; N, 2.95. Found: C, 68.19; H, 5.67; N, 2.94.
Synthesis of 3c
To a solution ◦of H[1c] (100 mg, 0.32 mmol) in diethyl ether
(6 mL) at -35 C was added ZnEt2 (0.32 mL, 1.0 M in hexanes,
0.32 mmol). The reaction mixture was naturally warmed to room
temperature and stirred overnight. A reaction aliquot was taken
◦
1
ether solution at -35 C; yield 74.6 mg (60%). H NMR (C6D6,
200 MHz) d 7.22 (d, 1H, Ar), 7.05 (m, 2H, Ar), 6.91 (m, 2H, Ar),
6.42 (t, 1H, Ar), 6.23 (t, 1H, Ar), 2.31 (s, 6H, ArMe), 1.80 (m, 2H,
CHMe2), 0.89 (dd, 6H, CHMe2), 0.80 (dd, 6H, CHMe2), -0.15
and examined by 31P{ H} NMR spectroscopy which showed the
1
quantitative formation of 3c. The diethyl ether solution was filtered
through a pad of Celite, which was further washed with diethyl
ether (2 mL ¥ 2) until the washings became colorless. The diethyl
ether filtrate and washings were combined, concentrated under
(d, 3H, JHP = 4.2, ZnCH3). 31P{ H} NMR (C6D6, 202.3 MHz)
3
1
d -14.04. 31P{ H} NMR (diethyl ether, 80.95 MHz) d -13.53.
1
13C{ H} NMR (C6D6, 125.5 MHz) d 163.2 (d, JCP = 15.6, C),
1
149.7 (d, JCP = 6.9, C), 135.0 (s, C), 134.0 (s, CH), 133.7 (s, CH),
129.5 (s, CH), 124.1 (s, CH), 113.4 (d, JCP = 5.5, CH), 112.4 (d,
JCP = 4.5, CH), 106.7 (d, JCP = 37.5, C), 22.9 (d, JCP = 16.9,
CHMe2), 19.8 (d, JCP = 9.5, PCHMe2), 19.4 (s, ArCH3), 18.4
(d, JCP = 2.3, PCHMe2), -12.6 (br s, ZnCH3). Anal. Calcd for
C21H30NPZn: C, 64.18; H, 7.70; N, 3.57. Found: C, 64.48; H, 7.63;
N, 3.20.
◦
reduced pressure, and cooled to -35 C to afford the product as
yellow crystals suitable for X-ray diffraction analysis; yield 86 mg
1
(66%). H NMR (C6D6, 500 MHz) d 7.21 (d, 2H, Ar), 7.06 (t,
1H, Ar), 6.96 (t, 1H, Ar), 6.90 (t, 1H, Ar), 6.42 (t, 1H, Ar), 6.22
(dd, 1H, Ar), 2.30 (s, 6H, ArCH3), 1.84 (m, 2H, CHMe2), 1.40 (t,
3H, ZnCH2CH3), 0.91 (dd, 6H, CHMe2), 0.82 (dd, 6H, CHMe2),
0.66 (q, 2H, ZnCH2). 31P{ H} NMR (C6D6, 202.3 MHz) d -12.94.
1
1
1
31P{ H} NMR (diethyl ether, 80.95 MHz) d -12.58. 13C{ H} NMR
(C6D6, 125.5 MHz) d 163.2 (d, JCP = 15.6, C), 149.5 (d, JCP = 6.4,
C), 134.9 (s, C), 134.0 (s, CH), 133.7 (s, CH), 129.5 (s, CH), 124.1
(s, CH), 113.4 (d, JCP = 5.0, CH), 112.6 (d, JCP = 5.0, CH), 106.9
Synthesis of 2d
To a solution of H[1d] (141 mg, 0.38 mmol) in diethyl ether
(2 mL) at -35 ◦C was added ZnMe2 (0.32 mL, 1.2 M in toluene,
0.38 mmol). The reaction mixture was naturally warmed to room
temperature and stirred for 2 h. Removal of all volatiles under
reduced pressure afforded the product as yellow oil in quantitative
yield. Crystallization of the product in hexane at -35 ◦C gave
(d, JCP = 36.7, C), 23.0 (d, JCP = 16.1, CHMe2), 19.9 (d, JCP
=
9.7, CHMe2), 19.3 (s, ArCH3), 18.5 (d, JCP = 2.3, CHMe2), 13.1
(s, ZnCH2CH3), 1.5 (d, 2JCP = 36.7, ZnCH2CH3). Anal. Calcd for
C22H32NPZn: C, 64.92; H, 7.93; N, 3.44. Found: C, 65.05; H, 7.94;
N, 2.99.
1
yellow crystals; yield 64 mg (45%). H NMR (C6D6, 300 MHz)
d 7.33 (m, 3H, Ar), 6.96 (t, 1H, Ar), 6.88 (td, 1H, Ar), 6.38 (t,
1H, Ar), 6.19 (dd, 1H, Ar), 3.43 (septet, 2H, ArCHMe2), 1.85 (m,
2H, PCHMe2), 1.30 (d, 6H, ArCHMe2), 1.23 (d, 6H, ArCHMe2),
0.93 (dd, 6H, PCHMe2), 0.85 (dd, 6H, PCHMe2), -0.16 (s, 3H,
Synthesis of 3d
To a solution of H[1d] (118 mg, 0.32 mmol) in diethyl ether (2 mL)
at -35 ◦C was added ZnEt2 (0.32 mL, 1 M in toluene, 0.32 mmol).
The reaction mixture was naturally warmed to room temperature
and stirred for 2 h. Removal of all volatiles under reduced pressure
afforded the product as yellow oil; yield 144 mg (98%). 1H NMR
(C6D6, 300 MHz) d 7.29 (m, 3H, Ar), 6.96 (td, 1H, Ar), 6.90 (td,
1H, Ar), 6.39 (t, 1H, Ar), 6.19 (dd, 1H, Ar), 3.42 (septet, 2H,
ArCHMe2), 1.85 (m, 2H, PCHMe2), 1.41 (td, 3H, ZnCH2CH3),
1.30 (d, 6H, ArCHMe2), 1.23 (d, 6H, ArCHMe2), 0.96 (dd, 6H,
ZnCH3). 31P{ H} NMR (C6D6, 121.5 MHz) d -13.82. 13C{ H}
NMR (C6D6, 75.5 MHz) d 164.9 (d, JCP = 7.6, C), 146.8 (s, C),
145.6 (s, C), 133.8 (s, CH), 133.6 (s, CH), 125.3 (s, CH), 124.6 (s,
CH), 113.9 (d, JCP = 4.4, CH), 113.3 (d, JCP = 5.3, CH), 106.5
(d, JCP = 38.5, C), 28.9 (s, ArCHMe2), 25.4 (s, ArCHMe2), 24.2
(s, ArCHMe2), 23.0 (d, JCP = 17.4, PCHMe2), 19.7 (d, JCP = 9.1,
PCHMe2), 18.4 (s, PCHMe2), -12.6 (br s, ZnMe).
1
1
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PCHMe2), 0.86 (dd, 6H, PCHMe2), 0.66 (q, 2H, ZnCH2CH3).
Synthesis of 5c
1
1
31P{ H} NMR (C6D6, 121.5 MHz) d -13.23. 13C{ H} NMR
To a solution of H[1c] (500 mg, 1.6 mmol) in THF (5 mL) at -35 ◦C
was added n-BuLi (1.00 mL, 1.6 M in hexane, 1.6 mmol). The
reaction mixture was naturally warmed to room temperature and
stirred for 3 h. All volatiles were removed in vacuo. The red viscous
residue was triturated with pentane (10 mL) to yield a yellow solid.
The yellow solid was isolated from the orange solution, washed
with pentane (5 mL ¥ 2), and dried in vacuo; yield 718 mg (99%).
Yellow crystals suitable for X-ray diffraction◦analysis were grown
from a concentrated pentane solution at -35 C. 1H NMR (C6D6,
500 MHz) d 7.27 (d, 2H, Ar), 7.19 (t, 1H, Ar), 7.09 (t, 1H, Ar),
6.99 (t, 1H, Ar), 6.44 (t, 1H, Ar), 6.25 (t, 1H, Ar), 3.37 (br s, 8H,
OCH2CH2), 2.39 (s, 6H, ArCH3), 2.13 (m, 2H, CHMe2), 1.27 (br s,
8H, OCH2CH2), 1.21 (m, 6H, CHMe2), 1.17 (m, 6H, CHMe2).
(C6D6, 75.5 MHz) d 164.8 (d, JCP = 15.1, C), 147.0 (d, JCP
=
6.8, C), 145.5 (s, C), 133.8 (s, CH), 133.6 (s, CH), 125.3 (s, CH),
124.5 (s, CH), 113.8 (d, JCP = 4.5, CH), 113.4 (d, JCP = 5.3, CH),
106.6 (d, JCP = 36.2, C), 28.9 (s, CHMe2), 25.2 (s, CHMe2), 24.2
(s, CHMe2), 23.1 (d, JCP = 16.6, PCHMe2), 19.8 (d, JCP = 9.8,
PCHMe2), 18.5 (s, PCHMe2), 13.2 (s, ZnCH2CH3), 1.5 (d, JCP
37.0, ZnCH2CH3).
=
Synthesis of 4a
To a diethyl ether solution (3 mL) of H[1a] (100 mg, 0.26 mmol) at
-35 ◦C was added ZnMe2 (0.065 mL, 2.0 M in toluene, 0.13 mmol).
The solution was stirred at room temperature overnight and
filtered through a pad of Celite, which was further washed with
diethyl ether (2 mL ¥ 2) until the washings became colorless. The
filtrates were combined, concentrated under reduced pressure to
ca. 4 mL, and cooled to -35 ◦C to afford the product as a yellow
1
7
1
7Li{ H} NMR (C6D6, 194 MHz) d 1.41 (Dv1/2 = 29.4). Li{ H}
◦
1
NMR (toluene-d8, -30 C, 194 MHz) d -3.65 (d, JLiP = 45.6).
1
1
31P{ H} NMR (C6D6, 202 MHz) d -7.90 (Dv1/2 = 29). 31P{ H}
◦
NMR (THF, 81 MHz) d -8.84. 31P{ H} NMR (toluene-d8, -30 C,
1
202 MHz) d -10.89 (1 : 1 : 1 : 1 q, JLiP = 45.6). 13C{ H} NMR
(C6D6, 125.5 MHz) d 165.2 (d, JCP = 21.4, C), 155.6 (s, C), 134.1
(s, C), 133.6 (d, JCP = 2.5, CH), 131.9 (s, CH), 128.9 (s, CH), 120.2
(s, CH), 112.6 (s, CH), 112.1 (d, JCP = 11.3, C), 108.8 (s, CH), 68.5
(s, OCH2CH2), 25.8 (s, OCH2CH2), 24.0 (br s, CHMe2), 21.0 (d,
JCP = 14.3, CHMe2), 20.3 (d, JCP = 9.2, CHMe2), 19.9 (s, ArCH3).
Anal. Calcd for C28H43LiNO2P: C, 72.52; H, 9.35; N, 3.02. Found:
C, 72.01; H, 9.27; N, 3.19.
1
1
1
solid; yield 91 mg (84%). H NMR (C6D6, 500 MHz) d 7.32 (m,
8H, Ar), 7.06 (m, 2H, Ar), 6.95–7.00 (m, 12H, Ar), 6.72–6.87 (m,
4H, Ar), 6.71 (m, 4H, Ar), 6.27 (t, 2H, Ar), 6.21 (m, 2H, Ar), 1.96
1
(s, 6H, CH3), 1.82 (s, 6H, CH3). 31P{ H} NMR (C6D6, 202.5 MHz)
1
d -28.63. 31P{ H} NMR (THF, 202.5 MHz) d -29.39. 13C NMR
(C6D6, 125.7 MHz) d 163.1 (JCP = 19.9), 163.1, 137.3, 136.1 (CH),
135.7, 134.1 (CH), 133.9 (CH), 133.8 (CH), 130.3 (CH), 129.7
(CH), 129.0 (CH), 128.9 (CH), 114.2 (CH, JCP = 19.9), 109.5
(JCP = 44.5), 109.5, 19.5 (Me), 19.0 (Me).
Synthesis of 5d
Synthesis of 4d
Method 1: To a solution of N-(2-bromophenyl)-2,6-diisopropyl-
aniline (1.00 g, 3.01 mmol) in diethyl ether (20 mL) at -35 ◦C
was added n-BuLi (3.8 mL, 1.6 M in hexane, 6.02 mmol,
2 equiv.). The reaction solution was naturally warmed to room
temperature with stirring. After being stirred at room temperature
for 1 h, the reaction mixture was cooled to -35 ◦C again and
chlorodiisopropylphosphine (459 mg, 3.01 mmol) was added.
The reaction solution was stirred at room temperature overnight
and filtered through a pad of Celite, which was further washed
with diethyl ether (5 mL ¥ 2). The filtrate and washings were
combined and dimethoxyethane (271 mg, 3.01 mmol) was added.
The solution was concentrated under reduced pressure to ca. 2 mL
and cooled to -35 ◦C to afford the product as pale yellow crystals
suitable for X-ray diffraction analysis; yield 711 mg (51%). Method
2: Direct deprotonation of H[1d] with 1 equiv. of n-BuLi in DME
Solid Zn(OAc)2 (18 mg, 0.2 mmol) was suspended in THF (1 mL)
and cooled to -35 ◦C. To this was added a pre-chilled solution
of 5d (93 mg, 0.2 mmol) in THF (4 mL) at -35 ◦C. The reaction
mixture was stirred at room temperature for 6 h and evaporated to
dryness under reduced pressure. The solid residue was triturated
with pentane (2 mL ¥ 2) and diethyl ether (6 mL) was added. The
ether solution was filtered through a pad of Celite and evaporated
to dryness under reduced pressure. Pentane (1 mL) was added.
The pentane solution was cooled to -35 ◦C to afford the product
as pale yellow crystals suitable for X-ray diffraction analysis; yield
68 mg (69%). 1H NMR (C6D6, 500 MHz) d 7.18 (m, 6H, Ar), 6.86
(t, 2H, Ar), 6.78 (t, 2H, Ar), 6.34 (t, 2H, Ar), 6.16 (t, 2H, Ar),
3.94 (septet, 2H, ArCHMe2), 3.51 (septet, 2H, ArCHMe2), 2.32
(septet of doublets, 2H, PCHMe2), 1.93 (septet of doublets, 2H,
PCHMe2), 1.34 (d, 6H, CHMe2), 1.25 (m, 12H, CHMe2), 1.05
(dd, 6H, CHMe2), 0.97 (d, 6H, CHMe2), 0.94 (d, 6H, CHMe2),
◦
1
at -35 C gave quantitative formation of 5d as indicated by 31P{ H}
1
NMR. H NMR (C6D6, 500 MHz) d 7.34 (d, 2H, Ar), 7.18 (m,
0.86 (m, 6H, CHMe2), 0.34 (dd, 6H, PCHMe2). 31P{ H} NMR
2H, Ar), 7.11 (td, 1H, Ar), 7.03 (td, 1H, Ar), 6.38 (t, 1H, Ar), 6.13
(dd, 1H, Ar), 3.64 (septet, 2H, ArCHMe2), 2.87 (s, 6H, OMe), 2.69
(s, 4H, OCH2), 2.09 (m, 2H, PCHMe2), 1.34 (d, 6H, ArCHMe2),
1.27 (d, 6H, ArCHMe2), 1.21 (dd, 6H, PCHMe2), 1.14 (dd, 6H,
1
(C6D6, 202.5 MHz) d -12.55. 13C{ H} NMR (C6D6, 125.5 MHz)
1
d 165.5 (t, JCP = 17.4, C), 150.3 (s, C), 148.4 (s, C), 145.6 (s, C),
132.4 (d, JCP = 22.9, CH), 128.7 (s, CH), 125.2 (s, CH), 125.1
1
1
(s, CH), 124.6 (s, CH), 120.8 (d, JCP = 102.9, C), 118.5 (t, JCP
=
PCHMe2). 31P{ H} NMR (C6D6, 203 MHz) d -7.29 (q, JPLi
=
1
1
3.0, CH), 113.2 (t, JCP = 4.5, CH), 28.7 (s, ArCHMe2), 28.39 (s,
49). 31P{ H} NMR (Et2O, 81 MHz) d -8.15. 7Li{ H} NMR (C6D6,
1
ArCHMe2), 28.37 (s, CHMe2), 25.6 (s, CHMe2), 25.34 (t, JCP
11.7, PCHMe2), 25.33 (s, CHMe2), 23.3 (s, CHMe2), 21.8 (t, JCP
=
=
194 MHz) d 1.63 (d, 1JPLi = 49). 13C{ H} NMR (C6D6, 125.5 MHz)
d 167.2 (d, JCP = 21, C), 153.0 (d, JCP = 2.3, C), 144.9 (s, C), 133.4
(d, JCP = 2.8, CH), 131.4 (s, CH), 124.1 (s, CH), 121.6 (s, CH),
6.9, PCHMe2), 20.2 (t, JCP = 7.3, PCHMe2), 19.9 (t, JCP = 15.6,
PCHMe2), 18.4 (br s, CHMe2), 17.8 (br s, CHMe2). Anal. Calcd for
C48H70N2P2Zn: C, 71.83; H, 8.80; N, 3.49. Found: C, 71.52; H, 8.71;
N, 3.35.
114.1 (d, JCP = 5.0, CH), 111.7 (d, JCP = 12.4, C), 108.7 (d, JCP
=
2.8, CH), 70.3 (s, OCH2), 59.3 (s, OCH3), 28.3 (s, CH), 25.9 (s,
CH3), 25.0 (s, CH3), 24.1 (s, CH), 21.1 (d, JCP = 15.2, CH3), 20.4
8756 | Dalton Trans., 2010, 39, 8748–8758
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©

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(d, JCP = 8.7, CH3). Anal. Calcd for C28H45LiNO2P: C, 72.21; H,
001, and 96-2918-I-110-011), Mr Ting-Shen Kuo (NTNU) for
assistance with X-ray crystallography, Ms Ching-Wei Lu (NTU),
Ms I-Chuan Chen (NCHU) and Ms Chia-Chen Tsai (NCKU) for
elemental analysis, Ms Chao-Lien Ho (NSYSU), Ms Mei-Yueh
Chien (NCHU) and Ms Ru-Rong Wu (NCKU) for assistance with
NMR, and the National Center for High-performance Computing
(NCHC) for accesses to chemical databases.
9.75; N, 3.01. Found: C, 67.51; H, 8.25; N, 2.15.
Synthesis of 6c
To a solution of H[1c] (200 mg, 0.64 mmol) in THF (6 mL)
was added ZnCl2 (1.28 mL, 0.5 M in THF, 0.64 mmol) at
room temperature. The reaction solution was stirred at room
temperature for 2 h and evaporated to dryness under reduced
pressure. The solid residue was gently washed with diethyl ether
(2 mL ¥ 2) and dried in vacuo to afford the product as an off-
References
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1
white solid; yield 205 mg (71%). H NMR (C6D6, 500 MHz) d
6.99 (m, 3H, Ar and NH), 6.89 (t, 1H, Ar), 6.80 (t, 1H, Ar), 6.54
(m, 2H, Ar), 6.38 (dd, 1H, Ar), 2.30 (s, 6H, ArCH3), 2.25 (m, 2H,
1
CHMe2), 1.31 (dd, 6H, CHMe2), 0.93 (dd, 6H, CHMe2). 31P{ H}
1
NMR (C6D6, 202.5 MHz) d -7.73 (Dv1/2 = 65). 13C{ H} NMR
(C6D6, 125.5 MHz) d 151.9 (d, JCP = 9.2, C), 138.7 (s, C), 135.6
(s, C), 134.4 (s, CH), 133.3 (s, CH), 129.7 (s, CH), 126.4 (s, CH),
120.2 (d, JCP = 6.4, CH), 117.2 (d, JCP = 5.5, CH), 110.6 (d, JCP
=
5.4, C), 24.2 (d, 1JCP = 22.0, CHMe2), 19.38 (s, CHMe2), 19.35 (s,
CHMe2), 17.8 (s, ArCH3).
Synthesis of 7c
9 C. K. Williams, L. E. Breyfogle, S. K. Choi, W. Nam, V. G. Young,
M. A. Hillmyer and W. B. Tolman, J. Am. Chem. Soc., 2003, 125,
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2666–2673.
To a solution of 6c (112 mg, 0.25 mmol) in THF (6 mL) was added
n-BuLi (0.1 mL, 2.5 M in hexane, 0.25 mmol) at -35 ◦C. The
reaction solution was stirred at room temperature for 2 h and
evaporated to dryness under reduced pressure. Pentane (8 mL)
was added. The pentane solution was filtered through a pad of
Celite and evaporated to dryness under reduced pressure to afford
the product as pale yellow oil; yield 80 mg (73%). 1H NMR (C6D6,
300 MHz) d 7.20 (m, 2H, Ar), 7.05 (t, 1H, Ar), 6.93 (m, 2H, Ar),
6.40 (t, 1H, Ar), 6.15 (t, 1H, Ar), 2.27 (s, 6H, ArCH3), 1.87 (m,
2H, CHMe2), 1.69 (m, 2H, CH2), 1.32 (m, 2H, CH2), 0.94 (m, 9H,
CHMe2 mixed with CH3), 0.82 (dd, 6H, CHMe2), 0.73 (m, 2H,
12 L.-C. Liang, P.-S. Chien and Y.-L. Huang, J. Am. Chem. Soc., 2006,
128, 15562–15563.
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16 L.-C. Liang, M.-H. Huang and C.-H. Hung, Inorg. Chem., 2004, 43,
2166–2174.
ZnCH2). 31P{ H} NMR (C6D6, 121.5 MHz) d -14.43. 13C{ H}
NMR (C6D6, 125.5 MHz) d 163.1 (d, JCP = 14.71, C), 149.7 (s,
C), 135.1 (br s, C), 134.0 (s, CH), 133.7 (s, CH), 129.3 (s, CH),
124.1 (s, CH), 113.3 (br s, C), 112.7 (s, CH), 112.6 (s, CH), 30.1
(s, CH2), 23.1 (d, JCP = 18.4, PCH), 19.8 (d, JCP = 7.4, PCHMe2),
19.3 (s, CH3), 18.4 (s, CH3), 15.2 (br s, CH2), 14.7 (s, CH3), 1.8
(br s, ZnCH2).
1
1
17 B. L. Tran, M. Pink and D. J. Mindiola, Organometallics, 2009, 28,
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Catalytic ROP of e-CL
23 D. J. Darensbourg, M. S. Zimmer, P. Rainey and D. L. Larkins, Inorg.
A toluene solution of 2 or 3 (2.0 mM) was added to a toluene
solution of e-CL (with prescribed concentration based on [e-
CL]0/[Zn]0 rations shown in Table 4). Toluene was added, if
necessary, to make the total volume of the reaction solution
become 4 mL. The solution was transferred to a Teflon-sealed
reaction vessel and heated to 80 ◦C for 2 h. After being cooled
to room temperature, the reaction solution was quenched with a
methanol solution of HCl. The solid thus precipitated was washed
with hexane, isolated, and dried under reduced pressure until
constant weights.
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Acknowledgements
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We thank the National Science Council of Taiwan for finan-
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31 N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, A. G. Mackie and
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This journal is
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Dalton Trans., 2010, 39, 8748–8758 | 8757
©

View Article Online
◦
-1
˚
˚
˚
32 A. Eichhofer, D. Fenske and O. Fuhr, Z. Anorg. Allg. Chem., 1997, 623,
762–768.
14.6308(2) A, b = 21.8029(4) A, c = 15.9501(3) A, b = 90.8220(10) ,
3
˚
V = 5087.46(15) A , T = 200(2) K, Z = 4, m(Mo-Ka) = 0.575 mm ,
30 751 reflections measured, 8884 unique (Rint = 0.0771) which were
used in all calculations. Final R1 [I > 2s(I)] = 0.0599, wR2 [I >
2s(I)] = 0.1766, R1 (all data) = 0.0982, wR2 (all data) = 0.2112,
GOF (on F2) = 0.758, CCDC 773059. 5c: C28H43LiNO2P, M = 463.54,
33 M. Save, M. Schappacher and A. Soum, Macromol. Chem. Phys., 2002,
203, 889–899.
34 M. Haddad, M. Laghzaoui, R. Welter and S. Dagorne,
Organometallics, 2009, 28, 4584–4592.
35 Crystal data for 2c: C21H30NPZn, M = 392.62, monoclinic, space group
˚
˚
triclinic, space group P1, a = 9.2124(3) A, b◦= 9.3766(3) A, c =
◦
◦
˚
˚
˚
˚
˚
18.2449(7) A, a = 77.7120(10) , b = 78.2640(10) , g = 67.232(2) , V =
P21/c, a = 14.6479(5) A, b = 8.9972(3) A, c = 15.6842(6) A, b =
◦
3
3
-1
˚
94.579(2) , V = 2060.42(13) A , T = 200(2) K, Z = 4,m(Mo-Ka) =
1407.04(8) A , T = 200(2) K, Z = 2, m(Mo-Ka) = 0.120 mm , 18 628
reflections measured, 5025 unique (Rint = 0.0964) which were used in all
calculations. Final R1 [I > 2s(I)] = 0.0937, wR2 [I > 2s(I)] = 0.2116,
R1 (all data) = 0.1706, wR2 (all data) = 0.2776, GOF (on F2) = 1.081,
CCDC 773060. 5d: C28H45LiNO2P, M = 465.56, orthorhombic, space
1.272 mm-1, 11 371 reflections measured, 3730 unique (Rint = 0.0662)
which were used in all calculations. Final R1 [I > 2s(I)] = 0.0556, wR2
[I > 2s(I)] = 0.1508, R1 (all data) = 0.0713, wR2 (all data) = 0.1725,
GOF (on F2) = 1.142, CCDC 773056. 2d: C25H38NPZn, M = 448.90,
˚
˚
˚
˚
˚
monoclinic, space group P21/n,◦a = 12.5895(3) A, b = 13.6322(4) A, c =
group Pbn21, a = 10.7145(3) A, b = 15.3867(5) A, c = 17.6868(6) A, V =
3 -1
˚
3
˚
˚
12.7248(4) A, b = 90.0190(10) , V = 2527.11(12) A , T = 200(2) K,
Z = 4, m(Mo-Ka) = 1.045 mm-1, 13 704 reflections measured, 4207
unique (Rint = 0.0740) which were used in all calculations. Final R1
[I > 2s(I)] = 0.0583, wR2 [I > 2s(I)] = 0.1461, R1 (all data) =
0.0979, wR2 (all data) = 0.1910, GOF (on F2) = 1.203, CCDC
2915.86(16) A , T = 200(2) K, Z = 4, m(Mo-Ka) = 0.116 mm , 13 751
reflections measured, 4376 unique (Rint = 0.0533) which were used in
allcalculations. Final R1 [I > 2s(I)] = 0.0837, wR2 [I > 2s(I)] = 0.1914,
R1 (all data) = 0.1159, wR2 (all data) = 0.2194, GOF (on F2) = 1.163,
CCDC 773061. 6c: C40H56Cl4N2P2Zn2, M = 899.35, monoclinic, space
˚
˚
˚
773057. 3c: C22H32NPZn, M = 406.83, triclinic, space group P1, a =
group P21/c, a = 9.2599(4) A, b = 12.7189(7) A, c = 17.0867(9) A, b =
◦
◦
3
˚
˚
˚
˚
8.6210(2) A, b = 9.1959(2) A, c = 14.8726(4) A, a = 106.0720(10) , b =
90.465(2) ,V = 2170.55(18) A , T = 200(2) K, Z = 2, m(Mo-Ka) =
◦
◦
3
˚
91.3470(10) , g = 106.9420(10) , V = 1076.83(4) A , T = 200(2) K,
Z = 2, m(Mo-Ka) = 1.219 mm-1, 13 672 reflections measured, 3796
unique (Rint = 0.0469) which were used in all calculations. Final R1
[I > 2s(I)] = 0.0344, wR2 [I > 2s(I)] = 0.0887, R1 (all data) =
0.0437, wR2 (all data) = 0.0949, GOF (on F2) = 1.099, CCDC 773058.
4d: C48H70N2P2Zn, M = 802.37, monoclinic, space group P21/c, a =
1.455 mm-1, 13 719 reflections measured, 3792 unique (Rint = 0.1073)
which were used in all calculations. Final R1 [I > 2s(I)] = 0.0895, wR2
[I > 2s(I)] = 0.2023, R1 (all data) = 0.1543, wR2 (all data) = 0.2427,
GOF (on F2) = 1.146, CCDC 773062.
36 A. L. Spek, PLATON - A Multipurpose Crystallographic Tool, Utrecht
University, The Netherlands, 2003.
8758 | Dalton Trans., 2010, 39, 8748–8758
This journal is
The Royal Society of Chemistry 2010
©