Synthesis, structure, and ring-opening polymerization catalysis of zinc complexes containing amido phosphinimine ligands

Article abstract of DOI:10.1002/ejic.201001362

A series of amido phosphinimine ligands of the type [(NAr ¹)-o-(Ph₂P=NAr²)C₆H ₄]^- (2a: Ar¹ = 2,6-C₆H ₃iPr₂, Ar² = 2,6-C₆H ₃iPr₂; 2b: Ar¹ = 2,6-C₆H ₃iPr₂, Ar² = 2,4,6-C₆H ₂Me₃; 2c: Ar¹ = 2,6-C₆H ₃Me₂, Ar² = 2,4,6-C₆H ₂Me₃), which are electronic variations of monoanionic β-diketiminates, have been employed to examine the coordination chemistry of zinc. Alkane elimination reactions of ZnR₂ (R = Me, Et) with H[2a-c] in toluene or ethereal solutions at -35 °C afforded cleanly the corresponding organozinc complexes [2a-c]ZnMe (3a-c) and [2a-c]ZnEt (4a-c). Deprotonation of H[2a-c] with nBuLi at -35 °C generated [2a-c]Li (5a-c), which may be isolated as either solvent-free complexes or solvated adducts depending on the reaction solvents employed (toluene, OEt2, or THF). Metathetical reactions of 5a·OEt₂ with Zn(OAc)₂ in THF at -35 °C produced [2a]Zn(OAc) (6a). These amido phosphinimine derivatives all display solution C_s symmetry on the NMR timescale. The mononuclear nature of the three-coordinate alkyls 3-4 and four-coordinate acetate 6a was confirmed by single-crystal X-ray diffraction analyses. Interestingly, the alkyl complexes 3a-c and 4a-c are all active initiators for the catalytic ring-opening polymerization of Iμ-caprolactone, whereas the acetate 6a is comparatively inactive. Copyright

Full text of DOI:10.1002/ejic.201001362

FULL PAPER
DOI: 10.1002/ejic.201001362
Synthesis, Structure, and Ring-Opening Polymerization Catalysis of Zinc
Complexes Containing Amido Phosphinimine Ligands
Lan-Chang Liang,*[a] Tzung-Ling Tsai,[a] Chun-Wei Li,[a] Yu-Lin Hsu,[a] and Ting-Yu Lee[b]
Keywords: Zinc / N,P ligands / Ring-opening polymerization
A series of amido phosphinimine ligands of the type [(NAr1)-
o-(Ph2P=NAr2)C6H4]– (2a: Ar1 = 2,6-C6H3iPr2, Ar2 = 2,6-
C6H3iPr2; 2b: Ar1 = 2,6-C6H3iPr2, Ar2 = 2,4,6-C6H2Me3; 2c:
as either solvent-free complexes or solvated adducts de-
pending on the reaction solvents employed (toluene, OEt2,
or THF). Metathetical reactions of 5a·OEt2 with Zn(OAc)2 in
Ar1 = 2,6-C6H3Me2, Ar2 = 2,4,6-C6H2Me3), which are elec- THF at –35 °C produced [2a]Zn(OAc) (6a). These amido pho-
tronic variations of monoanionic β-diketiminates, have been
employed to examine the coordination chemistry of zinc. Al-
kane elimination reactions of ZnR2 (R = Me, Et) with H[2a–
c] in toluene or ethereal solutions at –35 °C afforded cleanly
the corresponding organozinc complexes [2a–c]ZnMe (3a–c)
and [2a–c]ZnEt (4a–c). Deprotonation of H[2a–c] with nBuLi
at –35 °C generated [2a–c]Li (5a–c), which may be isolated
sphinimine derivatives all display solution Cs symmetry on
the NMR timescale. The mononuclear nature of the three-
coordinate alkyls 3–4 and four-coordinate acetate 6a was
confirmed by single-crystal X-ray diffraction analyses. Inter-
estingly, the alkyl complexes 3a–c and 4a–c are all active ini-
tiators for the catalytic ring-opening polymerization of ε-cap-
rolactone, whereas the acetate 6a is comparatively inactive.
have recently been demonstrated.[42] Herein, we describe the
synthesis, structural characterization, and ROP activities of
zinc amido phosphinimine complexes. Differences in the
structure and reactivity of these compounds relative to
those of their parent amido phosphane[42,43] and β-diket-
iminate derivatives[12,13] are discussed.
Introduction
The search for controlled methods to prepare biocompat-
ible and biodegradable polymers such as poly(ε-capro-
lactone) (PCL) and polylactide is of current interest in view
of their potential applications in drug delivery, absorbable
stitches, and environmentally friendly thermoplastics,
etc.[1,2] Significant recent advances in this respect have been
made with the metal-mediated ring-opening polymerization
(ROP) of lactones.[3–6] The active catalysts involved are usu-
ally alkoxide complexes of main group metals (e.g. Li,[7–9] Results and Discussion
Mg,[10–13] Zn,[11–23] Al,[24,25] Sn,[26] etc.), group 3 and lan-
thanides (e.g. Y,[27] La,[28] etc.), and transition metals (e.g.
Ligand Synthesis
group 4,[29] Fe,[30] etc.). Of particular note are zinc com-
plexes of tris(pyrazolyl)hydroborates[11] and β-diketimin-
Following established protocols,[31] the protio ligand pre-
ates,[12,13] which have shown remarkable catalytic activities
in a controlled manner. We are currently exploring the reac-
tion chemistry with metal complexes of amido phosphin-
imine ligands,[31] which may be regarded as an electronic
modification of β-diketiminates. The amido phosphinimine
ligands are oxidative derivatives of amido phosphanes,[32–41]
and the catalytic activities of zinc alkyl complexes of these
ligands with respect to the ROP of ε-caprolactone (ε-CL)
cursors H[2] were readily prepared by Staudinger reac-
tions[44] of N-(2-diphenylphosphanylphenyl)-2,6-dialkyl-
aniline (H[1])[36,43] with appropriate organoazides[45–47] in
toluene or DME solutions at 80 °C (Scheme 1). Piers et al.
recently described a distinct strategy to prepare H[2a][48]
and H[2b].[49] Compounds H[2a–c] were all isolated as
1
colorless crystalline materials. Solution H and 13C NMR
spectroscopic data of these compounds are consistent with
a time-averaged Cs symmetry. For instance, the two o-alkyl
groups in each N-aryl moiety are all chemically equivalent,
so are the two phosphorus-bound phenyl rings. Consistent
with the more oxidized nature of the phosphinimine func-
tionality, the 31P chemical shifts of H[2a–c] (Table 1) are all
comparatively downfield from those of H[1] (ca.
–20 ppm).[36,43] The acidic NH proton of H[2a–c] resonates
at 9–10 ppm.
[a] Department of Chemistry and Center for Nanoscience &
Nanotechnology,
National Sun Yat-sen University,
Kaohsiung 80424, Taiwan
E-mail: lcliang@mail.nsysu.edu.tw
[b] Department of Applied Chemistry,
National University of Kaohsiung,
Kaohsiung 81148, Taiwan
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201001362.
2948
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 2948–2957

ROP Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands
(NMR spectroscopy evidence) even at elevated tempera-
tures (e.g. 100 °C), a result that is markedly different from
that found with 1,[42,43] but ascribable to the increased steric
hindrance for the amido phosphinimine ligands because of
the larger chelating rings. The formation rates of 3–4 appear
to increase in the order a Ͻ b Ͻc, consistent with that ex-
pected from a steric standpoint. Prior to the formation of
the zinc alkyls 3–4, no intermediate was detected by
31P{1H} NMR spectroscopy, in contrast to that found for
the corresponding aluminum chemistry.[31] Interestingly,
these three-coordinate zinc alkyls do not bind strong coor-
dinating solvents such as THF or diethyl ether in spite of
their coordinatively unsaturated nature, which highlights
the sufficient steric crowdedness imposed by these amido
phosphinimine ligands. The preparation of three-coordinate
zinc complexes that are free of coordinating solvents is of
current interest.[14,42,43,52–57] The successful isolation of 3c
and 4c from THF solutions is noteworthy in view of the
relatively small steric size of 2c. In general, these alkyls are
thermally stable under an inert atmosphere, even at elevated
temperatures (100 °C, Ͼ24 h), but extremely sensitive to
moisture, producing exclusively H[2] as indicated by
31P{1H} NMR spectroscopy.
Solution NMR spectroscopic data of 3–4 are all consis-
tent with a time-averaged Cs symmetry for these molecules.
In all cases, the o-alkyl moieties in each N-aryl group are
chemically equivalent. The 31P chemical shifts all move sig-
nificantly downfield from those of their corresponding pro-
tio ligands (Table 1). This phenomenon is notably different
from the parent amido phosphane chemistry.[42,43] Where
resolved, the Hα or Cα atom exhibits a doublet resonance,
e.g. in 3c, 4b, and 4c, consistent with the coordination of
phosphinimine functionality to the zinc center.
Scheme 1. Synthesis of ligands and zinc alkyl complexes.
Table 1. Selected NMR spectroscopic data.[a]
Compound
δHα
δCα
δP
H[2a]
H[2b]
H[2c]
3a
0.7
0.9
1.6
–0.42
–0.50
–0.46[b]
0.52
0.40
0.44
–17.2
–16.0
–16.5
–0.8
28.5
24.4
23.9
27.4
24.0
23.3
19.0
19.9
19.4
13.3
14.7
32.3[e]
3b
3c
4a
4b
–0.8[c]
–1.2[d]
4c
5a·OEt2
5a·THF
5a
5b
5c·OEt2
6a
The solid-state structures of 3a–c and 4a–c were all deter-
mined by X-ray crystallography (Figures 1 and 2). Selected
bond lengths and angles are summarized in Tables 2 and 3,
respectively. Consistent with the solution NMR studies,
these complexes are monomeric, three-coordinate species
that do not bind any ethereal ligands, even though these
compounds were prepared in ethereal solutions. The geom-
etry of the coordination core is best described as trigonal
planar as indicated by the sum (360°) of the bond angles
about the zinc atom in all cases. The N=P distances are
somewhat elongated relative to those of protio H[2a]
[1.5582(13) Å],[48] H[2b] [1.5634(19) Å],[49] and H[2c]. The
Zn–N distances are slightly longer for the phosphinimine
nitrogen than for the amido nitrogen, likely reflective of the
anionic nature of the latter and the mismatch involving the
comparatively soft phosphinimine and the hard ZnII center.
In comparison, the two Zn–N distances in [BDI-iPr]ZnMe
are virtually identical [1.9480(18) Å and 1.9429(18) Å].[52]
[a] All spectra were recorded in C6D6 at room temperature unless
otherwise noted, chemical shifts in ppm. [b] 4JHP = 1.5 Hz. [c] 3JCP
3
= 1.9 Hz. [d] JCP = 1.4 Hz. [e] Recorded in CDCl3.
Figure S1 depicts the molecular structure of H[2c]. Bond
lengths and angles are unexceptional. The N-phenylene-P
atoms are essentially co-planar; the phosphinimine nitrogen
atom, however, is notably displaced from the mean N-phen-
ylene-P plane by 0.641 Å. A similar phenomenon is also
found for H[2a][48] and H[2b].[49] These results are in sharp
contrast to the coplanarity of the N2C3 backbone in β-
diketimine derivatives such as [{(2,6-R2C6H3)NCMe}2-
CH]H ([BDI-R]H, R = iPr),[50] which indicates an inferior
π-delocalization nature for H[2a–c].
Synthesis and Characterization of the Zinc Complexes
Alkane elimination reactions of dialkylzinc with H[2a– As a result, the steric pressure imposed by the amido arm
c] in toluene or ethereal solutions at –35 °C produced the in 3a–c and 4a–c appears to be more significant than that
corresponding complexes [2a–c]ZnR {R = Me (3a–c), Et of the phosphinimine side, which leads to larger C–Zn–N
(4a–c)} in high isolated yields. Conversely, relatively harsh angles for the former. The alkyl group is thus tilted toward
conditions (Ն80 °C, overnight to 3 d) appear to be neces- the phosphinimine side. In 3a–c and 4a–c, the N–Zn–N bite
sary for similar reactions involving β-diketimines.[51,52] No angles of ca. 101° are notably sharper than the two C–Zn–
sign of the formation of the bis-2 complex was detected N angles, but nevertheless wider than the corresponding
Eur. J. Inorg. Chem. 2011, 2948–2957
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2949

L.-C. Liang, T.-L. Tsai, C.-W. Li, Y.-L. Hsu, T.-Y. Lee
FULL PAPER
Figure 1. Molecular structures of 3a (left), 3b (middle), and 3c (right) with thermal ellipsoids drawn at the 35% probability level. All
hydrogen atoms are omitted for clarity.
Figure 2. Molecular structures of 4a (left), 4b (middle), and 4c (right) with thermal ellipsoids drawn at the 35% probability level. All
hydrogen atoms are omitted for clarity.
values in derivatives of 1 (ca. 85°)[42,43] and β-diketiminate
In addition to zinc alkyls, zinc alkoxides and carboxyl-
[e.g. 97.00(8)° in (BDI-iPr)ZnMe[52] and 97.07(12)° in (BDI- ates are both intriguing as they are also potential initiators
iPr)ZnEt].[51] Similarly to that of their protio ligands, the for catalytic ROP of heterocycles.[13–15,51,58–63] Our initial
phosphinimine nitrogen atom in 3–4 is significantly dis- plans to prepare zinc alkoxides of 2 involve alcoholysis of
placed from the mean N-phenylene-P plane, so are the zinc zinc alkyls 3–4 with a variety of alcohols. Unfortunately,
center and the associated Cα atom. The π delocalization in these reactions undesirably led to protonation on the amido
the six-membered chelating rings of 3–4 is thus likely poor nitrogen donor in 2, consistent with the moisture sensitivity
and insignificant.
of 3–4 as mentioned before. Similar phenomena, however,
have also been reported for systems employing 1[42] or bis-
(phosphinimine)methyl ligands.[53]
Table 2. Selected bond lengths [Å] for 3a–c and 4a–c.
Scheme 2 illustrates a second strategy involving a lithium
intermediate. The lithium complexes 5a–c were readily pre-
pared by treating H[2a–c] with nBuLi in toluene or ethereal
solutions at –35 °C. Depending on the reaction solvents em-
ployed, 5 may be isolated as solvent-free derivatives or ethe-
real adducts. Piers et al. recently reported the preparation
of solvent-free 5a,b;[48,49] however, the NMR spectroscopic
data of those solvent-free compounds appear not to differ
much from those of ethereal adducts prepared in this study.
For instance, the phosphorus atom in 5a, 5a·OEt2, and
5a·THF consistently resonates at ca. 19.5 ppm in the
Compound Zn–C
Zn–Namide Zn–Nphosphinimine N=P
3a
1.949(5)
1.960(3)
1.963(7)
1.959(3)
1.964(3)
1.953(3)
1.942(5)
2.017(3)
2.006(7)
2.007(3)
2.009(3)
2.005(3)
2.007(4)
1.601(3)
1.585(7)
1.599(3)
1.607(3)
1.604(3)
1.603(4)
3b[a]
3c
1.948(9)
1.939(5)
1.962(4)
1.944(4)
1.963(6)
4a
4b
4c[a]
[a] Data represent one of two independent molecules found in the
asymmetric unit.
Table 3. Selected bond angles [°] for 3a–c and 4a–c.
1
31P{1H} NMR spectra. The H and 13C{1H} NMR spec-
Compound
N–Zn–N
C–Zn–Namide
C–Zn–Nphosphinimine
troscopic data are consistent with a Cs symmetry on the
NMR timescale.
3a
101.84(13)
101.1(3)
101.51(14)
101.51(10)
100.78(11)
100.80(19)
136.73(19)
130.0(4)
132.8(2)
130.94(14)
132.29(17)
136.5(2)
121.41(19)
128.9(4)
125.7(2)
127.29(14)
126.86(17)
122.7(2)
3b[a]
3c
Treatment of Zn(OAc)2 with 5a·OEt2 in THF at –35 °C
led to slow dissolution of Zn(OAc)2 and generated cleanly
[2a]Zn(OAc) (6a) as evidenced by 31P{1H} NMR spec-
troscopy. Conversely, similar reactions involving 5b, 5c, or
their corresponding ethereal adducts gave a mixture of
products; attempts to isolate the desired acetate complexes
4a
4b
4c[a]
[a] Data represent one of two independent molecules found in the
asymmetric unit.
2950
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 2948–2957

ROP Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands
hybrid orbitals of zinc to bind the amido phosphinimine
ligand. The four-membered Zn(η2-acetate) ring is essen-
tially coplanar. The Zn–O distance is slightly shorter for O1
than for O2 and the C1–O1 length is a bit longer than C1–
O2, which indicates a somewhat stronger π character for
the C1–O2 bond.
Figure 3. Molecular structure of 6a with thermal ellipsoids drawn
at the 35% probability level. All hydrogen atoms are omitted for
clarity. Selected bond lengths [Å] and angles [°]: N1–Zn1 1.951(8),
N2–P1 1.616(8), N2–Zn1 1.977(8), O1–Zn1 2.022(7), O2–Zn1
2.100(7), C1–O2 1.230(13), C1–O1 1.284(13), N1–Zn1–N2
106.6(3), O1–Zn1–O2 63.5(3).
Scheme 2. Synthesis of lithium and zinc acetate complexes.
from these reaction mixtures were not successful. Reactions
of 5a–c with ZnCl2 led undesirably to intractable materials.
In comparison, analogous experiments employing 1 and
ZnX2 (X=OAc, Cl), regardless of stoichiometry employed,
produced exclusively bis-ligated Zn[1]2 without any detec-
tion of the desired [1]ZnX complexes.[42,43] The successful
Catalysis
Catalytic ROP of ε-CL by the derived zinc complexes
isolation of 6a thus highlights the advantage of 2 relative to was examined. Table 4 summarizes the polymerization re-
1 in view of the synthesis of zinc acetate derivatives. Simi- sults and characterization data. Interestingly, the alkyl de-
larly to 3 and 4, 6a is thermally stable at elevated tempera- rivatives 3a–c and 4a–c are all quite active (93% to quanti-
tures (100 °C, Ͼ24 h).
tative conversion) under the conditions investigated. In ge-
Complex 6a was isolated as colorless crystals in high neral, the (corrected)[64,65] number-averaged molecular
yield from a concentrated diethyl ether solution at –35 °C. weights (Mn) of PCL measured by gel permeation
All NMR spectroscopic data are consistent with a time- chromatography (GPC) are comparatively higher than
averaged Cs symmetry. The acetate ligand exhibits a singlet those expected (Entries 1–11). Nevertheless, they are ap-
1
at δ = 1.79 ppm in the H NMR spectrum and a diagnostic proximately proportional to the theoretical values or to the
C=O signal at δ = 184.7 ppm in the 13C NMR spectrum. monomer-to-catalyst ratios (Entries 6–11, Figures S2 and
Coates et al. previously reported a monomer/dimer equilib- S3), which indicates that the propagating chains grow in a
rium in solution for {[BDI-iPr]Zn(μ-OAc)}2 and the exclus- reasonably controlled manner. Similar phenomena were
ive dimer for sterically less-demanding {[BDI-Et]Zn(μ- also found for zinc alkyl complexes of 1.[42] The relatively
OAc)}2 and {[BDI-Me]Zn(μ-OAc)}2.[51,58] The solution low polydispersity index (PDI) of ca. 1.6 for these PCLs
structure of these species is apparently a function of the indicates reasonably narrow molecular weight distributions,
steric size of the β-diketiminate ligands. Nevertheless, they which suggests that the catalytically active species are con-
all exist as a dimer in the solid state.[51,58] In contrast, we formationally similar, though not single-site.[11,13] The com-
found no evidence for such an equilibrium mixture in solu- paratively higher PDI found for reactions conducted with
1
tion in the H and 31P{1H} NMR spectra of 6a. An X- lower monomer-to-catalyst ratios (e.g. Entries 6 and 8) indi-
ray diffraction analysis confirms a monomeric core for this cates that transesterification is more significant. In sharp
molecule (Figure 3). The coordination geometry around the contrast, polymerization initiated by acetate 6a under sim-
zinc atom is best described as distorted tetrahedral. The ilar conditions is rather unsatisfactory (48% conversion),
Zn–Namide, Zn–Nphosphinimine, and N=P distances are all which produces only low molecular weight oligomers (En-
similar to those of 3–4. The N–Zn–N bite angle of 6a, how- try 13). This result is surprising as {[BDI-iPr]Zn(μ-OAc)}2
ever, is notably wider than the corresponding values of 3– is a highly active ROP catalyst for a number of cyclic mole-
4. In comparison, the N–Zn–N bite angles of mononuclear cules.[13,51,58] It has been shown that the steric hindrance
(BDI)ZnR are comparable to those of dinuclear [(BDI)- imposed by the β-diketiminate ligands in {[BDI]Zn(μ-
Zn(μ-OAc)]2.[51] The wider N–Zn–N bite angle in 6a than OAc)}2 is essential to encourage the formation of catalyti-
in 3–4 is thus ascribed to the coordination mode (chelating cally active [BDI]Zn(μ-OAc) in solution.[51] Given that 6a
instead of bridging) of the acetate ligand, wherein the sharp is mononuclear, even in the solid state, its low activity in
O–Zn–O angle implies a more s character is involved in the ROP catalysis thus reflects intrinsic discrepancy between
Eur. J. Inorg. Chem. 2011, 2948–2957
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2951

L.-C. Liang, T.-L. Tsai, C.-W. Li, Y.-L. Hsu, T.-Y. Lee
FULL PAPER
Table 4. Catalytic ROP of ε-CL by 3a–c, 4a–c, and 6a.[a]
Entry [ε-CL]0/[Zn]0
Catalyst
Conv. [%][b]
10–3Mn (calcd.)[c] 10–3Mn (GPC)[d] Corrected 10–3Mn (GPC)[e] PDI[d]
1
2
3
4
5
6
7
8
125
125
125
125
125
25
50
75
100
125
150
150
100
3a
4a
3b
4b
3c
4c
4c
4c
4c
4c
4c
4c
6a
100
100
100
94
100
100
93
100
95
100
100
100
48
14.3
14.3
14.3
13.3
14.3
2.9
5.3
8.6
10.8
14.3
17.1
17.1
5.5
60.0
50.6
64.3
55.6
67.3
12.2
27.9
45.8
57.1
75.8
98.3
23.2
1.7[b]
33.6
28.3
36.0
31.1
37.7
6.8
15.6
25.7
32.0
42.4
55.0
13.0
1.31
1.63
1.68
1.43
1.52
2.52
1.80
2.95
1.57
1.50
1.47
1.20
9
10
11
12[f]
13
[a] Conditions: [Zn]0 = 2.0 mm, toluene, 80 °C, 1.5 h;[66] Mn values are reported in g/mol. [b] Determined by 1H NMR analysis. [c]
Calculated from (Fw of ε-CL) ϫ ([ε-CL]0/[Zn]0) ϫ conversion, by 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.[64,65] [f] Conducted in the presence of 2-propanol
(2.0 mm).
amido phosphinimines and β-diketiminates, particularly in result that is in contrast to those established by β-diketimin-
view of the observed larger N–Zn–N bite angle for the for- ate complexes. Interestingly, 3a–c and 4a–c are all quite
mer, which allows η2-acetate coordination. End group active, producing PCLs with molecular weights and molec-
1
analysis by H NMR spectroscopy on PCL prepared with ular weight distributions in a reasonably controlled manner.
3c reveals the presence of keto methyl and hydroxy methyl-
ene signals with an integral ratio of 3:2, which suggests that
the Zn–Me bond in 3c participates in the initial ring open-
ing of the coordinated ε-CL. The zinc alkoxide intermediate
thus generated then undergoes successive ring opening for
Experimental Section
General Procedures: Unless otherwise specified, all experiments
were performed under nitrogen by using standard Schlenk or
chain propagation. Upon acidic workup, the zinc alkoxide
glovebox techniques. All solvents were reagent grade or better and
chain end is protonated to produce the hydroxy end group.
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 (δ)
are listed as parts per million downfield from tetramethylsilane,
A coordination–insertion mechanism is thus likely to be in
operation in this system. In reactions conducted in [D8]tolu-
ene with 1 equiv. of monomer, PCL is produced upon com-
plete monomer consumption, while the majority of the zinc
and coupling constants (J) and peak widths at half-height (Δv1/2
)
alkyl remains intact (Ͼ70%), as indicated by 1H NMR are in Hertz. 1H NMR spectra are referenced by using the residual
solvent peak at δ = 7.16 for C6D6 and δ = 7.27 for CDCl3. 13C
NMR spectra are referenced to the internal solvent peak at δ =
studies. This result strongly suggests that the zinc alkyl initi-
ation rates are significantly slower than the zinc alkoxide
propagation rates. This also explains, at least in part, why
the measured Mn value is larger than the expected value.
Accordingly, when the catalysis was conducted in the pres-
ence of alcohol (1 equiv. with respect to zinc), the experi-
mental and theoretical Mn values are much closer (Entry
12) with a slightly lower PDI.
128.39 for C6D6 and δ = 77.23 for CDCl3. The assignment of the
carbon atoms for all new compounds is based on DEPT 13C NMR
spectroscopy. 31P and 7Li NMR spectra are referenced externally
by using 85% H3PO4 at δ = 0 and LiCl in D2O at δ = 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. Af-
ter multiple attempts, we were not able to obtain satisfactory analy-
sis for some complexes reported herein likely because of incomplete
combustion of the samples examined. Gel permeation chromatog-
raphy (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 with a 1515 Isocratic HPLC Pump. Molecular
weights (Mn and Mw) were determined by interpolation from cali-
bration plots established with polystyrene standards.
Conclusions
We have prepared a series of amido phosphinimine com-
plexes of zinc and established their solution and solid-state
structures by means of NMR spectroscopy and X-ray crys-
tallography. Of particular note is the successful isolation of
monomeric, coordinatively unsaturated alkyls 3a–c and 4a–
c that do not adopt strong coordinating solvents. Attempts
to prepare the corresponding zinc chloride and alkoxide de-
rivatives, however, were not successful. The successful isola-
tion of the mononuclear acetate 6a highlights the unique
coordination property of 2a in comparison with those of 1
and β-diketiminates. Surprisingly, though 6a is mononu-
Materials: Compounds N-(2-diphenylphosphanylphenyl)-2,6-di-
methylaniline,[36]
N-(2-diphenylphosphanylphenyl)-2,6-diisopro-
pylaniline,[43] 2,6-diisopropylphenylazide,[45,46] 2,4,6-trimethylphen-
ylazide,[47] H[2a],[31] 5a,[48] and 5b[49] were prepared according to
literature procedures.
Synthesis of H[2b]: To a toluene solution (4 mL) of N-(2-diphenyl-
clear, it is a rather poor catalyst for the ROP of ε-CL, a phosphanylphenyl)-2,6-diisopropylaniline (107.8 mg, 0.25 mmol)
2952 Eur. J. Inorg. Chem. 2011, 2948–2957
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ROP Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands
was added 2,4,6-trimethylphenylazide (39.7 mg, 0.25 mmol) at
room temperature. The solution was transferred to a Teflon-sealed
reaction vessel and heated to 80 °C overnight. After being cooled
to room temperature, the solution was filtered through a pad of
Celite, and the solvents evaporated to dryness under reduced pres-
sure. Acetonitrile (3 mL) and diethyl ether (2 mL) were added. Slow
evaporation of the solution at room temperature afforded the prod-
uct as pale yellow crystals. Yield: 112.5 mg (80%). Spectroscopic
data are identical to those reported by Piers et al. by a different
synthetic strategy.[49]
(691.79): calcd. C 74.59, H 7.43, N 4.05; found C 70.69, H 7.98, N
3.78.
Synthesis of 3b: Solid H[2b] (109.4 mg, 0.19 mmol) was dissolved
in diethyl ether (4 mL) and cooled to –35 °C. To this was added
ZnMe2 (0.16 mL, 1.2 m in toluene, 0.19 mmol). The reaction solu-
tion was naturally warmed to room temperature and stirred for 7 h.
All volatiles were removed. The solid residue was triturated with
pentane (4 mL) and dissolved in diethyl ether (2 mL). Cooling of
the ether solution to –35 °C afforded the product as pale yellow
crystals. Yield: 96 mg (77%). 1H NMR (C6D6, 500 MHz): δ = 7.63
(m, 4, Ar), 7.25 (m, 3, Ar), 6.98 (m, 4, Ar), 6.90 (m, 4, Ar), 6.67
(s, 2, Ar), 6.38 (t, 1, Ar), 6.21 (td, 1, Ar), 2.96 (septet, 2, CHMe2),
2.40 (s, 6, o-C6H2Me3), 2.07 (s, 3, p-C6H2Me3), 1.11 (d, 6, CHMe2),
1.09 (d, 6, CHMe2), –0.50 (s, 3 ZnCH3) ppm. 31P{1H} NMR
Synthesis of H[2c]: To a DME solution (4 mL) of N-(2-diphenyl-
phosphanylphenyl)-2,6-dimethylaniline (200 mg, 0.52 mmol) was
added 2,4,6-trimethylphenylazide (101 mg, 0.63 mmol, 1.2 equiv.)
at room temperature. The solution was transferred to a Teflon-
sealed reaction vessel and heated to 80 °C for 2 d. After being co-
oled to room temperature, the solution was filtered through a pad
of Celite, and the solvents evaporated to dryness under reduced
pressure. The orange solid thus obtained was washed with pentane
(2 mL ϫ2) and triturated with acetonitrile (4 mL) to give the prod-
uct as an off-white solid. Yield: 210 mg (78%). 1H NMR (C6D6,
500 MHz): δ = 9.60 (s, 1, NH), 7.76 (m, 4, Ar), 7.09 (dd, 1, Ar),
7.00 (m, 2, Ar), 6.95 (m, 5, Ar), 6.92 (m, 3, Ar), 6.88 (s, 2, Ar),
6.43 (t, 1, Ar), 6.36 (dd, 1, Ar), 2.34 (s, 6, o-C6H2Me3), 2.22 (s, 3,
p-C6H2Me3), 1.96 (s, 6, o-C6H3Me2) ppm. 31P{1H} NMR (C6D6,
202.5 MHz): δ = 1.61 ppm. 13C{1H} NMR (C6D6, 125.5 MHz): δ
= 152.00 (d, JCP = 4.14 Hz, 1 C), 145.37 (d, JCP = 4.51 Hz, C),
138.62 (s, C), 136.46 (s, C), 133.37 (d, JCP = 3.63 Hz,CH), 133.34
(s, C), 133.32 (d, JCP = 5.14 Hz, CH), 133.19 (s, C), 133.18 (d, JCP
= 9.16 Hz, CH), 132.58 (s, C), 131.60 (d, JCP = 2.63 Hz, CH),
(C6D6, 202.5 MHz):
δ =
24.39 ppm. 13C{1H} NMR (C6D6,
125.5 MHz): δ = 161.08 (d, JCP = 4.39 Hz, C), 146.41 (s, C), 145.67
(s, C), 142.41 (d, JCP = 7.61 Hz, 1 C), 135.30 (d, JCP = 5.90 Hz, 1
C), 134.36 (s, CH), 133.77 (d, JCP = 9.29 Hz, CH), 133.08 (d, JCP
= 11.80 Hz, CH), 132.79 (d, JCP = 2.38 Hz, CH), 132.61 (d, JCP
3.39 Hz, C), 130.06 (d, JCP = 3.01 Hz, CH), 129.02 (d, JCP
=
=
11.78 Hz, CH), 128.83 (d, JCP = 36.40 Hz, C), 125.54 (s, CH),
124.64 (s, CH), 117.18 (d, JCP = 8.28 Hz, CH), 111.80 (d, JCP
=
13.80 Hz, CH), 109.22 (d, JCP = 103.63 Hz, C), 28.20 (s, CHMe2),
25.33 (s, CHMe2), 25.30 (s, CHMe2), 21.10 (s, p-C6H2Me3), 21.04
(s, o-C6H2Me3), –15.99 (s, ZnCH3) ppm. C40H45N2PZn (649.74):
calcd. C 73.88, H 6.98, N 4.31; found C 74.05, H 7.16, N 4.04.
Synthesis of 3c: Solid H[2c] (100 mg, 0.19 mmol) was dissolved in
THF (3 mL) and cooled to –35 °C. To this was added ZnMe2
(0.16 mL, 1.2 m in toluene, 0.19 mmol). The reaction solution was
naturally warmed to room temperature and stirred for 1 h. After
being filtered through a pad of Celite, the solution was evaporated
to dryness under reduced pressure. The solid was then triturated
with pentane (4 mL) and dissolved in diethyl ether (2 mL). Cooling
of the ether solution to –35 °C afforded the product as colorless
crystals. Yield: 84 mg (74%). 1H NMR (C6D6, 500 MHz): δ = 7.63
(dd, 4, Ar), 7.13 (m, 2, Ar), 6.97 (m, 5, Ar), 6.88 (m, 4, Ar), 6.66
(s, 2, Ar), 6.41 (t, 1, Ar), 6.27 (td, 1, Ar), 2.33 (s, 6, o-ArMe), 2.06
129.79 (d, JCP = 2.79 Hz, CH), 129.28 (s, CH), 128.79 (d, JCP
=
11.9 Hz, CH), 126.29. (s, CH), 116.52 (d, JCP = 13.3 Hz, CH),
115.46 (d, JCP = 107.42 Hz, C), 113.93 (d, JCP = 8.15 Hz, CH),
21.88 (s, o-C6H2Me3), 21.23 (s, p-C6H2Me3), 18.95 (s, o-C6H3Me2)
ppm. C35H35N2P (514.25): calcd. C 81.67, H 6.86, N 5.45; found
C 82.04, H 6.86, N 5.08.
Synthesis of 3a: Solid H[2a] (102.9 mg, 0.17 mmol) was dissolved
in toluene (2 mL) and cooled to –35 °C. To this was added ZnMe2
(0.14 mL, 1.2 m in toluene, 0.17 mmol). The reaction solution was
naturally warmed to room temperature and stirred for 12 h. After
being filtered through a pad of Celite, the solution was concen-
trated to ca. 1 mL and cooled to –35 °C to afford the product as
pale yellow crystals suitable for X-ray diffraction analysis. Yield:
97 mg (84%). 1H NMR (C6D6, 200 MHz): δ = 7.57 (dd, 4, Ar),
7.27 (m, 3, Ar), 7.00 (m, 11, Ar), 6.35 (m, 1, Ar), 6.20 (m, 1, Ar),
3.60 (septet, 2, CHMe2), 2.87 (septet, 2, CHMe2), 1.40 (d, 6,
CHMe2), 1.08 (dd, 12, CHMe2), 0.93 (d, 6, CHMe2), –0.42 (s, 1,
ZnCH3) ppm. 31P{1H} NMR (C6D6, 80.95 MHz): δ = 27.76 ppm.
1H NMR (CDCl3, 500 MHz): δ = 7.58 (m, 2, Ar), 7.50 (m, 4, Ar),
7.42 (m, 4, Ar), 7.11 (m, 3, Ar), 6.97 (m, 2, Ar), 6.95 (m, 2, Ar),
6.78 (dd, 1, Ar), 6.23 (m, 1, Ar), 6.00 (t, 1, Ar), 3.36 (septet, 2,
CHMe2), 2.64 (septet, 2, CHMe2), 1.23 (d, 6, CHMe2), 0.88 (d, 6,
CHMe2), 0.85 (d, 6, CHMe2), 0.80 (d, 6, CHMe2), –0.99 (d, 3,
4
(s, 3, p-C6H2Me3), 1.90 (s, 6, o-ArMe), –0.46 (d, 3, JPH = 1.5 Hz,
ZnCH3) ppm. 31P{1H} NMR (C6D6, 202.5 MHz): δ = 23.87 ppm.
13C{1H} NMR (C6D6, 125.5 MHz): δ = 159.64 (d, JCP = 4.64 Hz,
C), 150.60 (s, C), 142.50 (d, JCP = 7.28 Hz, C), 135.33 (s, C), 135.27
(s, C), 134.96 (d, JCP = 1.88 Hz, CH), 133.86 (d, JCP = 9.16 Hz,
CH), 133.04 (d, JCP = 11.42 Hz, CH), 132.76 (d, JCP = 2.76 Hz,
CH), 132.60 (d, JCP = 3.64 Hz, C), 130.01 (d, JCP = 2.76 Hz, CH),
129.47 (s, CH), 128.95 (d, JCP = 11.92 Hz, CH), 127.75 (s, C),
124.36 (s, CH), 115.61 (d, JCP = 8.28 Hz, CH), 112.03 (d, JCP
13.68 Hz, CH), 109.94 (d, JCP = 104.29 Hz, C), 21.18 (d, JCP
=
=
1.38 Hz, o-C6H2Me3), 21.11 (d, JCP = 1.38 Hz, p-C6H2Me3), 18.91
(s, o-C6H3Me2), –16.49 (s, ZnCH3) ppm. C36H37N2PZn (593.68):
calcd. C 72.77, H 6.28, N 4.72; found C 72.17, H 6.84, N 4.33.
Synthesis of 4a: Solid H[2a] (110.5 mg, 0.18 mmol) was dissolved
ZnCH3) ppm. 31P{1H} NMR (CDCl3, 202.5 MHz): δ = 28.49 ppm. in diethyl ether (2 mL) and cooled to –35 °C. To this was added
13C{1H} NMR (CDCl3, 125.5 MHz): δ = 160.36 (d, JCP = 4.64 Hz,
C), 145.81 (s, C), 145.42 (s, C), 145.37 (s, C), 141.24 (d, JCP
ZnEt2 (0.18 mL, 1 m in hexene, 0.18 mmol). The reaction solution
was naturally warmed to room temperature and stirred for 2 d. All
volatiles were removed. The solid residue was triturated with pen-
tane (4 mL) and dissolved in diethyl ether (2 mL). Cooling of the
=
8.28 Hz, C), 133.21 (d, JCP = 9.04 Hz, CH), 133.11 (s, CH), 132.48
(d, JCP = 11.92 Hz, CH), 132.34 (d, JCP = 2.76 Hz, CH), 128.46
(d, JCP = 11.92 Hz, CH), 127.07 (d, JCP = 98.77 Hz, C), 124.25 (s, ether solution to –35 °C afforded the product as colorless crystals.
1
CH), 123.74 (s, CH), 123.62 (d, JCP = 3.64 Hz, CH), 123.16 (d, JCP
= 2.76 Hz, CH), 116.92 (d, JCP = 8.16 Hz, CH), 110.92 (d, JCP
13.68 Hz, CH), 108.44 (d, JCP = 105.17 Hz, C), 29.16 (s, CHMe2),
Yield: 104 mg (82%). H NMR (C6D6, 500 MHz): δ = 7.56 (dd, 4,
Ar), 7.25 (m, 3, Ar), 6.99 (m, 4, Ar), 6.93 (m, 6, Ar), 6.87 (m, 1,
Ar), 6.28 (dd, 1, Ar), 6.18 (dt, 1, Ar), 3.60 (septet, 2, CHMe2), 2.87
=
27.31 (s, CHMe2), 25.11 (s, CHMe2), 24.92 (s, CHMe2), 24.76 (s, (septet, 2, CHMe2), 1.40 (d, 6, CHMe2), 1.20 (t, 3, ZnCH2CH3),
CHMe2), 22.71 (s, CHMe2), –17.15 (s, ZnCH3) ppm. C43H51N2PZn 1.08 (m, 12, CHMe2), 0.87 (d, 6, CHMe2), 0.52 (q, 2, ZnCH2CH3)
Eur. J. Inorg. Chem. 2011, 2948–2957
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2953

L.-C. Liang, T.-L. Tsai, C.-W. Li, Y.-L. Hsu, T.-Y. Lee
FULL PAPER
ppm. 31P{1H} NMR (C6D6, 202.5 MHz): δ = 27.38 ppm. 13C{1H}
Synthesis of 5a·OEt2: To a diethyl ether solution (5 mL) of H[2a]
NMR (C6D6, 125.5 MHz): δ = 161.29 (d, JCP = 4.52 Hz, C), 146.75 (214.4 mg, 0.35 mmol) at –35 °C was added nBuLi (0.14 mL, 2.5 m
(s, C), 145.94 (s, C), 145.91 (s, C), 142.15 (d, JCP = 8.28 Hz, C),
in hexane, 0.35 mmol). The solution was stirred at room tempera-
ture for 3 h and concentrated under reduced pressure until a vol-
ume of ca. 2 mL. The precipitate thus formed was collected and
134.11 (s, CH), 133.83 (d, JCP = 8.28 Hz, CH), 133.06 (d, JCP
11.92 Hz, CH), 132.80 (d, JCP = 1.88 Hz, CH), 129.00 (d, JCP
=
=
11.80 Hz, CH), 127.62 (s, C), 125.64 (s, CH), 124.82 (s, CH), 124.74 dried in vacuo to give the product as a yellow solid. Yield: 216 mg
(d, JCP = 3.64 Hz, CH), 124.17 (d, JCP = 3.77 Hz, CH), 117.86 (d, (89%). 1H NMR (C6D6, 500 MHz): δ = 7.65 (br. s, 4, Ar), 7.22 (m,
JCP = 8.16 Hz, CH), 111.95 (d, JCP = 13.68 Hz, CH), 109.23 (d,
JCP = 105.17 Hz, C), 29.98 (s, CHMe2), 28.18 (s, CHMe2), 26.20
(s, CHMe2), 25.96 (s, CHMe2), 25.48 (s, CHMe2), 23.58 (s,
2, Ar), 7.15 (m, 2, Ar), 7.08 (t, 2, Ar), 7.05 (m, 2, Ar), 7.02 (m, 4,
Ar), 6.93 (t, 1, Ar), 6.89 (td, 1, Ar), 6.17 (dd, 1, Ar), 6.07 (td,1,
Ar), 3.65 (septet, 2, CHMe2), 2.92 (q, 4, OCH2CH3), 2.85 (br. s, 2,
CHMe2), 13.19 (s, ZnCH2CH3), –0.81 (s, ZnCH2CH3) ppm. CHMe2), 1.32 (d, 6 CHMe2), 1.19 (d, 6, CHMe2), 0.98 (d, 6
C44H53N2PZn (705.80): calcd. C 74.81, H 7.57, N 3.97; found C
75.09, H 8.04, N 3.63.
CHMe2), 0.91 (br. d, 6, CHMe2), 0.58 (t, 6, OCH2CH3) ppm.
7Li{1H} NMR (C6D6, 194 MHz): δ = 1.75 (Δv1/2 = 12.19) ppm.
31P{1H} NMR (C6D6, 202.5 MHz): δ = 19.04 (Δv1/2 = 5.72) ppm.
13C{1H} NMR (C6D6, 125.5 MHz): δ = 163.21 (d, JCP = 5.89 Hz,
C), 150.93 (s, CH), 146.32 (d, JCP = 8.78 Hz, C), 145.17 (s, C),
Synthesis of 4b: Solid H[2b] (100.3 mg, 0.18 mmol) was dissolved
in THF (4 mL) and cooled to –35 °C. To this was added ZnEt2
(0.18 mL, 1 m in hexene, 0.18 mmol). The reaction solution was
naturally warmed to room temperature and stirred for 7 h. All vola-
tiles were removed. The solid residue was triturated with pentane
(4 mL) and dissolved in diethyl ether (2 mL). Cooling of the ether
solution to –35 °C afforded the product as pale yellow crystals.
145.14 (s, CH), 134.42 (d, JCP = 12.82 Hz, CH), 133.68 (d, JCP
8.65 Hz, CH), 133.36 (d, JCP = 1.75 Hz, CH), 131.70 (d, JCP
2.76 Hz, CH), 131.54 (d, JCP = 95.63 Hz, C), 128.52 (d, JCP
=
=
=
15.5 Hz, CH), 124.36. (s, CH), 123.98 (d, JCP = 3.2 Hz, CH),
123.12. (s, CH), 122.55 (d, JCP = 4.1 Hz, CH), 117.12. (d, JCP
8.65 Hz, CH), 110.47 (d, JCP = 108.93 Hz, C), 107.83 (d, JCP
=
=
1
Yield: 87 mg (74%). H NMR (C6D6, 500 MHz): δ = 7.64 (m, 4,
Ar), 7.24 (m, 3, Ar), 6.99 (m, 2, Ar), 6.92 (m, 6, Ar), 6.68 (s, 2,
Ar), 6.37 (dd, 1, Ar), 6.21 (td, 1, Ar), 2.95 (septet, 2, CHMe2), 2.41
(s, 6, o-C6H2Me3), 2.06 (d, 3, p-C6H2Me3), 1.19 (t, 3, ZnCH2CH3),
1.12 (d, 6, CHMe2), 1.08 (d, 6, CHMe2), 0.40 (q, 2, ZnCH2CH3)
ppm. 31P{1H} NMR (C6D6, 202.5 MHz): δ = 23.99 ppm. 13C{1H}
NMR (C6D6, 125.5 MHz): δ = 160.94 (d, JCP = 4.64 Hz, C), 146.56
14.1 Hz, CH), 65.51 (s, OCH2CH3), 29.32 (s, CHMe2), 27.84 (s,
CHMe2), 26.58 (s, CHMe2), 25.71 (s, CHMe2), 24.91 (s, CHMe2),
24.15 (s, CHMe2), 14.36 (s, OCH2CH3) ppm. C46H58LiN2OP
(692.44): calcd. C 79.72, H 8.44, N 4.04; found C 77.43, H 7.78, N
4.04.
(s, C), 145.64 (s, C), 142.56 (d, JCP = 7.28, C), 135.23 (d, JCP
=
Synthesis of 5a·THF: To a THF solution (3 mL) of H[2a] (91.9 mg,
5.52, C), 134.33 (d, JCP = 1.88, CH), 133.76 (d, JCP = 9.16, CH), 0.15 mmol) at –35 °C was added nBuLi (0.06 mL, 2.5 m in hexane,
133.08 (d, JCP = 11.92, CH), 132.79 (d, JCP = 2.64, CH), 132.56
(d, JCP = 3.64, C), 130.02 (d, JCP = 2.76, CH), 129.02 (d, JCP
11.92, CH), 128.82 (d, JCP = 33.76, C), 125.54 (s, CH), 124.63 (s,
CH), 117.02 (d, JCP = 8.28, CH), 111.81 (d, JCP = 13.81, CH),
0.15 mmol). The solution was stirred at room temperature for 1.5 h,
filtered through a pad of Celite, and concentrated under reduced
pressure until a volume of ca. 1 mL. Layering of pentane (2 mL)
on top of the concentrated solution followed by cooling of the solu-
=
109.40 (d, JCP = 104.29, C), 28.20 (s, CHMe2), 25.38 (s, CHMe2), tion to –35 °C afforded the product as a yellow crystalline solid.
1
25.24 (s, CHMe2), 21.11(s, p-C6H2Me3), 21.02 (s, o-C6H2Me3),
13.00 (s, ZnCH2CH3), –0.77 (d, JCP 1.88, ZnCH2CH3).
C41H47N2PZn (663.76): calcd. C 74.12, H 7.14, N 4.22; found C
74.59, H 7.56, N 4.31.
Yield 75 mg (72%). H NMR (C6D6, 500 MHz): δ = 7.66 (dd, 4,
Ar), 7.20 (m, 1, Ar), 7.17 (m, 1, Ar), 7.10 (m, 1, Ar), 7.05 (m, 9,
Ar), 6.97 (m, 1, Ar), 6.92 (m, 1, Ar), 6.21 (dd, 1, Ar), 6.08 (dt, 1,
Ar), 3.68 (septet, 2, CHMe2), 3.03 (t, 4, OCH2CH2), 2.93 (septet,
2, CHMe2), 1.34 (d, 6, CHMe2), 1.20 (d, 6, CHMe2), 1.02 (q, 4,
OCH2CH2), 1.00 (d, 6, CHMe2), 0.97 (d, 6, CHMe2) ppm. 31P{1H}
=
Synthesis of 4c: Solid H[2c] (104 mg, 0.20 mmol) was dissolved in
THF (3 mL) and cooled to –35 °C. To this was added ZnEt2
(0.20 mL, 1 m in toluene, 0.20 mmol). The reaction solution was
naturally warmed to room temperature and stirred for 1 h. After
being filtered through a pad of Celite, the solution was evaporated
to dryness under reduced pressure. The solid was then triturated
with pentane (4 mL) and dissolved in diethyl ether (2 mL). Cooling
of the ether solution to –35 °C afforded the product as colorless
crystals. Yield: 93 mg (76%). 1H NMR (C6D6, 500 MHz): δ = 7.64
(dd, 4, Ar), 7.12 (m, 2, Ar), 6.99 (m, 5, Ar), 6.89 (m, 4, Ar), 6.67
(s, 2, Ar), 6.40 (dd, 1, Ar), 6.27 (td, 1, Ar), 2.36 (s, 6, o-ArMe),
2.06 (d, 3, p-C6H2Me3), 1.91 (s, 6, o-ArMe), 1.20 (t, 3, ZnCH2CH3),
0.44 (q, 2, ZnCH2CH3) ppm. 31P{1H} NMR (C6D6, 202.5 MHz):
δ = 23.29 ppm. 13C{1H} NMR (C6D6, 125.5 MHz): δ = 159.50 (d,
JCP = 4.64 Hz, C), 150.18 (s, C), 142.61 (d, JCP = 7.28 Hz, C),
135.28 (s, C), 135.22 (s, C), 134.95 (d, JCP = 1.75 Hz, CH), 133.83
(d, JCP = 9.66 Hz, CH), 133.06 (d, JCP = 11.42 Hz, CH), 132.76
(d, JCP = 2.76 Hz, CH), 132.56 (d, JCP = 3.64 Hz, C), 129.97 (d,
JCP = 3.26 Hz, CH), 129.43 (s, CH), 128.96 (d, JCP = 11.92 Hz,
NMR (C6D6, 202.31 MHz): δ = 19.88 (Δν1/2 = 5.0) ppm. Li{1H}
7
NMR (C6D6, 194 MHz): δ = 2.63 (Δν1/2 = 11.4) ppm. 13C{1H}
NMR (C6D6, 125.70 MHz): δ = 163.06 (d, JCP = 5.53 Hz, C),
150.46 (s, C), 146.21 (d, JCP = 7.79 Hz, C), 145.18 (s, C), 145.10
(d, JCP = 6.91 Hz, C), 134.63 (d, JCP = 12.82 Hz, CH), 133.68 (d,
JCP = 8.80 Hz, CH), 133.52 (d, JCP = 1.76 Hz, CH), 131.79 (d, JCP
= 96.66 Hz, C), 131.61 (d, JCP = 2.77 Hz, CH), 128.57 (d, JCP
11.44 Hz, CH), 124.26 (s, CH), 123.95 (d, JCP = 3.65 Hz, CH),
123.05 (s, CH), 122.46 (d, JCP = 3.77 Hz, CH), 116.39 (d, JCP
8.30 Hz, CH), 110.98 (d, JCP = 109.11 Hz, C), 107.71 (d, JCP
14.71 Hz, CH), 68.59 (s, OCH2CH2), 29.40 (s, CHMe2), 27.81 (s,
CHMe2), 26.26 (s, CHMe2), 26.12 (s, CHMe2), 25.57 (s, CHMe2),
25.43 (s, OCH2CH2), 23.96 (s, CHMe2) ppm. C46H56LiN2OP
(690.43): calcd. C 79.95, H 8.18, N 4.06; found C 80.07, H 8.21, N
3.76.
=
=
=
Synthesis of 5c·OEt2: To a diethyl ether solution (3 mL) of H[2c]
(102.9 mg, 0.20 mmol) at –35 °C was added nBuLi (0.08 mL, 2.5 m
CH), 127.76 (s, C), 124.38 (s, CH), 115.44 (d, JCP = 8.79 Hz, CH), in hexane, 0.20 mmol). The solution was stirred at room tempera-
112.01 (d, JCP = 13.67 Hz, CH), 110.04 (d, JCP = 104.29 Hz, C), ture for 3 h, filtered through a pad of Celite, and concentrated un-
21.15 (d, JCP = 1.38 Hz, o-C6H2Me3), 21.14 (s, p-C6H2Me3), 18.83 der reduced pressure until a volume of ca. 2 mL. Cooling of the
(s, o-C6H3Me2), 13.00 (s, ZnCH2CH3), –1.15 (d, JCP = 1.38 Hz, solution to –35 °C afforded the product as a yellow solid. Yield:
ZnCH2CH3) ppm. C37H39N2PZn (607.69): calcd. C 73.06, H 6.47,
102 mg (85%). 1H NMR (C6D6, 500 MHz): δ = 7.73 (dd, 4, Ar),
N 4.61; found C 72.75, H 7.08, N 4.31.
7.13 (d, 2, Ar), 7.05 (m, 4, Ar), 6.98 (m, 3, Ar), 6.94 (t, 2, Ar), 6.80
2954
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 2948–2957

ROP Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands
(s, 2, Ar), 6.32 (dd, 1, Ar), 6.18 (tdd, 1, Ar), 2.84 (q, 4, OCH2CH3), ethyl ether molecules. Attempts to obtain a suitable disorder model
2.39 (d, 6, o-C6H2Me3), 2.19 (d, 3, p-C6H2Me3), 1.92 (s, 6, o-
failed. The SQUEEZE procedure of the program Platon[67] was
C6H3Me2), 0.60 (t, 6, OCH2CH3) ppm. 7Li{1H} NMR (C6D6, used to obtain a new set of F2 (hkl) values without the contribution
194 MHz): δ = 1.85 (Δv1/2 = 15.21) ppm. 31P{1H} NMR (C6D6, of solvent molecules, which leads to the presence of significant vo-
202.5 MHz): δ = 14.70 ppm. 13C{1H} NMR (C6D6, 125.5 MHz): δ
ids in these structures. The refinement reduced the R1 value to
0.0659 and 0.1131 for 3c and 6a, respectively. In 4a, the methyl
group in the ethyl ligand is disordered over two conformations in a
ratio of 50:50. In 4c, the ethyl ligand in one of the two independent
= 160.92 (d, JCP = 4.64 Hz, C), 153.61 (s, C), 146.20 (d, JCP
6.77 Hz, C), 134.75 (d, JCP = 6.40 Hz, C), 134.61 (d, JCP
=
=
12.42 Hz, CH), 134.74 (s, C), 134.29 (d, JCP = 1.88 Hz, CH), 133.50
(d, JCP = 8.65 Hz, CH), 132.74 (s, C), 131.95 (s, C), 131.54 (d, JCP molecules present in the asymmetric unit cell is disordered over two
= 2.76 Hz, CH), 129.63 (d, JCP = 3.26 Hz, CH), 128.91 (s, CH), conformations in a ratio of 50:50.
128.63 (d, JCP = 11.9 Hz, CH), 121.75 (s, CH), 114.24 (d, JCP
8.20 Hz, CH), 110.96 (d, JCP = 105.16 Hz, C), 107.96 (d, JCP
14.18 Hz, CH), 65.51 (s, OCH2CH3), 21.30 (s, o-C6H2Me3), 21.23
(s, p-C6H2Me3), 19.27 (s, o-C6H3Me2), 14.65 (s, OCH2CH3) ppm.
C39H44LiN2OP (594.33): calcd. C 78.74, H 7.46, N 4.71; found C
79.16, H 7.23, N 4.38.
=
=
Crystal Data for H[2c]: C35H35N2P, M = 514.62, monoclinic, space
group P21/c, a = 13.4638(2) Å, b = 16.6891(3) Å, c = 14.0599(3) Å,
β = 115.1710(10)°, V = 2859.25(9) Å3, T = 200(2) K, Z = 4, μ(Mo-
Kα) = 0.122 mm–1, 16780 reflections measured, 5021 unique (Rint
= 0.0510), which were used in all calculations. Final R1 [IϾ2σ(I)]
= 0.0539, wR2 [IϾ2σ(I)] = 0.1514, R1 (all data) = 0.0706, wR2 (all
data) = 0.1673, GOF (on F2) = 1.054, CCDC-787868.
Synthesis of 6a: Solid Zn(OAc)2 (35.5 mg, 0.19 mmol) was sus-
pended in THF (2 mL) and cooled to –35 °C. To this was added a
prechilled THF solution (3 mL) of 5a·OEt2 (122 mg, 0.18 mmol)
at –35 °C. The reaction mixture was naturally warmed to room
temperature and stirred for 3 h. All volatiles were removed. The
solid residue was triturated with pentane (4 mL). Diethyl ether
(6 mL) was added. The ether solution was filtered through a pad
of Celite and concentrated to ca. 4 mL. Cooling of the ether solu-
tion to –35 °C afforded the product as colorless crystals. Yield:
Crystal Data for 3a: C57H67N2PZn, M = 876.47, triclinic, space
¯
group P1, a = 9.855(2) Å, b = 13.685(3) Å, c = 19.478(4) Å, α =
87.787(4)°, β = 75.946(4)°, γ = 73.728(4)°, V = 2444.9 Å3, T =
200(2) K, Z = 2, μ(Mo-Kα) = 0.573 mm–1, 21413 reflections mea-
sured, 8554 unique (Rint = 0.0427), which were used in all calcula-
tions. Final R1 [IϾ2σ(I)] = 0.0595, wR2 [IϾ2σ(I)] = 0.1767, R1
(all data) = 0.0828, wR2 (all data) = 0.1949, GOF (on F2) = 1.092,
CCDC-787869.
1
99 mg (76%). H NMR (CDCl3, 500 MHz): δ = 7.68 (dd, 1, Ar),
7.58 (m, 1, Ar), 7.50 (m, 5, Ar), 7.44 (m, 3, Ar), 7.09 (m, 4, Ar),
6.99 (m, 2, Ar), 6.94 (m, 1, Ar), 6.82 (qd, 1, Ar), 6.25 (td, 1, Ar),
6.04 (t, 1, Ar), 3.38 (br. m, 2, CHMe2), 2.67 (br. m, 2, CHMe2),
1.79 (s, 3, OAc), 1.23 (d, 6,CHMe2), 0.87 (m, 12, CHMe2), 0.81 (d,
6, CHMe2) ppm. 31P{1H} NMR (CDCl3, 202.5 MHz): δ =
32.25 ppm. 13C{1H} NMR (CDCl3, 125.5 MHz): δ = 184.67 (s,
CH3CO2), 161.01 (d, JCP = 5.27 Hz, C), 145.89 (s, C), 145.72 (d,
JCP = 5.27 Hz, C), 144.16 (s, C), 140.21 (d, JCP = 8.28 Hz, C),
Crystal Data for 3b: C40H45N2PZn, M = 650.12, triclinic, space
group P1, a = 9.668(2) Å, b = 14.919(4) Å, c = 24.480(5) Å, α =
¯
88.825(4)°, β = 80.313(6)°, γ = 83.774(3)°, V = 3460.2(14) Å3, T =
200(2) K, Z = 4, μ(Mo-Kα) = 0.786 mm–1, 21269 reflections mea-
sured, 10506 unique (Rint = 0.1495), which were used in all calcula-
tions. Final R1 [IϾ2σ(I)] = 0.0770, wR2 [IϾ2σ(I)] = 0.1618, R1
(all data) = 0.2160, wR2 (all data) = 0.2211, GOF (on F2) = 0.924,
CCDC-787870.
133.51 (d, JCP = 9.28 Hz, CH), 133.26 (s, CH), 132.82 (d, JCP
11.92 Hz, CH), 132.60 (d, JCP = 2.63 Hz, CH), 128.56 (d, JCP
12.05 Hz, CH), 124.60 (s, CH), 124.27 (d, JCP = 3.63 Hz, CH),
123.86. (s, CH), 123.33 (d, JCP = 3.13 Hz, CH), 117.22 (d, JCP
8.40 Hz, CH), 111.30 (d, JCP = 14.06 Hz, CH), 108.03 (d, JCP
101.53 Hz, C), 29.17 (s, CHMe2), 27.27 (s, CHMe2), 25.07 (s,
CHMe2), 24.48 (s, CHMe2), 23.78 (s, CHMe2), 22.86 (s, CHMe2),
20.03 (s, CH3CO2) ppm. C44H51N2O2PZn (735.78): calcd. C 71.76,
H 6.99, N 3.81; found C 71.70, H 7.17, N 3.52.
=
=
Crystal Data for 3c: C36H37N2PZn, M = 594.02, monoclinic, space
group P21/n, a = 16.2190(4) Å, b = 13.1028(3) Å, c = 17.1130(5) Å,
β = 95.1530(10)°, V = 3622.06(16) Å3, T = 200(2) K, Z = 4, μ(Mo-
Kα) = 0.745 mm–1, 21372 reflections measured, 6380 unique (Rint
= 0.0761), which were used in all calculations. Final R1 [IϾ2σ(I)]
= 0.0659, wR2 [IϾ2σ(I)] = 0.1994, R1 (all data) = 0.0989, wR2 (all
data) = 0.2264, GOF (on F2) = 0.807, CCDC-787871.
=
=
Crystal Data for 4a: C95H114N4P2Zn2, M = 1504.58, triclinic, space
¯
group P1, a = 9.7042(2) Å, b = 13.2444(3) Å, c = 18.4008(5) Å, α
Catalytic Ring-Opening Polymerization of ε-CL: A toluene solution
of 3 or 4 (2.0 mm) was added to a toluene solution of ε-CL (with
a prescribed concentration based on the [ε-CL]0/[Zn]0 ratios shown
in Table 4). Toluene was added, if necessary, to a total volume of
4 mL for the reaction solution. The solution was transferred to a
Teflon-sealed reaction vessel and heated to 80 °C for 2 h. After the
solution was cooled to room temperature, the reaction was
quenched with a methanol solution of HCl. The solid thus precipi-
tated was washed with hexane, isolated, and dried under reduced
pressure until a constant weight was achieved.
= 103.0690(10)°, β = 105.4110(10)°, γ = 103.8160(10)°, V =
2105.40(9) Å3, T = 200(2) K, Z = 1, μ(Mo-Kα) = 0.655 mm–1,
24306 reflections measured, 7425 unique (Rint = 0.0559), which
were used in all calculations. Final R1 [IϾ2σ(I)] = 0.0504, wR2
[IϾ2σ(I)] = 0.1460, R1 (all data) = 0.0677, wR2 (all data) = 0.1684,
GOF (on F2) = 1.136, CCDC-787872.
Crystal Data for 4b: C41H47N2PZn, M = 664.15, orthorhombic,
space group Pcab, a = 15.73250(10) Å, b = 21.1429(2) Å, c =
21.7675(2) Å, V = 7240.54(11) Å3, T = 200(2) K, Z = 8, μ(Mo-
Kα) = 0.752 mm–1, 50691 reflections measured, 6388 unique (Rint
= 0.0695), which were used in all calculations. Final R1 [IϾ2σ(I)]
= 0.0512, wR2 [IϾ2σ(I)] = 0.1407, R1 (all data) = 0.0756, wR2 (all
data) = 0.1644, GOF (on F2) = 1.181, CCDC-787873.
X-ray Crystallography: Data were collected on a Bruker-Nonius
Kappa CCD diffractometer with graphite monochromated Mo-Kα
radiation (λ = 0.7107 Å). Structures were solved by direct methods
and refined by full-matrix least-squares procedures against F2 by
using the maXus or WinGX crystallographic software package. All Crystal Data for 4c: C37H39N2PZn, M = 608.04, orthorhombic,
full-weight non-hydrogen atoms were refined anisotropically. Hy-
drogen atoms were placed in calculated positions. The crystals of
6a were of poor quality but sufficient to establish the identity of
this molecule. The structures of 3c and 6a contain disordered di-
space group Pca21, a = 15.3108(2) Å, b = 16.6247(3) Å, c =
25.3025(5) Å, V = 6440.43(19) Å3, T = 200(2) K, Z = 8, μ(Mo-Kα)
= 0.840 mm–1, 26869 reflections measured, 10249 unique (Rint
=
0.0660), which were used in all calculations. Final R1 [IϾ2σ(I)] =
Eur. J. Inorg. Chem. 2011, 2948–2957
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2955

L.-C. Liang, T.-L. Tsai, C.-W. Li, Y.-L. Hsu, T.-Y. Lee
FULL PAPER
[17]
C. K. Williams, L. E. Breyfogle, S. K. Choi, W. Nam, V. G.
Young, M. A. Hillmyer, W. B. Tolman, J. Am. Chem. Soc. 2003,
125, 11350–11359.
0.0501, wR2 [IϾ2σ(I)] = 0.1296, R1 (all data) = 0.0776, wR2 (all
data) = 0.1548, GOF (on F2) = 1.064, CCDC-787874.
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
Crystal Data for 6a: C44H51N2O2PZn, M = 736.21, triclinic, space
group P1, a = 9.8702(6) Å, b = 13.3515(9) Å, c = 18.3945(14) Å, α
G. Labourdette, D. J. Lee, B. O. Patrick, M. B. Ezhova, P.
Mehrkhodavandi, Organometallics 2009, 28, 1309–1319.
C.-T. Chen, C.-Y. Chan, C.-A. Huang, M.-T. Chen, K.-F. Peng,
Dalton Trans. 2007, 4073–4078.
I. Barakat, P. Dubois, R. Jérôme, P. Teyssié, Macromolecules
1991, 24, 6542–6545.
Y. Hwang, J. Jung, M. Ree, H. Kim, Macromolecules 2003, 36,
8210–8212.
M. D. Jones, M. G. Davidson, C. G. Keir, L. M. Hughes, M. F.
Mahon, D. C. Apperley, Eur. J. Inorg. Chem. 2009, 635–642.
C. Di Iulio, M. D. Jones, M. F. Mahon, D. C. Apperley, Inorg.
Chem. 2010, 49, 10232–10234.
P. Dubois, C. Jacobs, R. Jérôme, P. Teyssié, Macromolecules
1991, 24, 2266–2270.
Y.-C. Liu, B.-T. Ko, C.-C. Lin, Macromolecules 2001, 34, 6196–
6201.
H. R. Kricheldorf, I. Kreiser-Saunders, C. Boettcher, Polymer
1995, 36, 1253–1259.
B. M. Chamberlain, Y. P. Sun, J. R. Hagadorn, E. W. Hem-
mesch, V. G. Young, R. Pink, M. A. Hillmyer, W. B. Tolman,
Macromolecules 1999, 32, 2400–2402.
¯
= 70.536(3)°, β = 89.745(3)°, γ = 75.842(2)°, V = 2208.2(3) Å3, T
= 200(2) K, Z = 2, μ(Mo-Kα) = 0.626 mm–1, 20930 reflections
measured, 7544 unique (Rint = 0.1141), which were used in all cal-
culations. Final R1 [IϾ2σ(I)] = 0.1131, wR2 [IϾ2σ(I)] = 0.3024,
R1 (all data) = 0.2231, wR2 (all data) = 0.3683, GOF (on F2) =
1.075, CCDC-787875.
Crystallographic data for this paper can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Supporting Information (see footnote on the first page of this arti-
cle): Molecular structure of H[2c] and plots of found Mn (cor-
rected) vs. calculated Mn and monomer-to-catalyst ratios are pre-
sented.
Acknowledgments
[28]
[29]
[30]
[31]
G. R. Giesbrecht, G. D. Whitener, J. Arnold, J. Chem. Soc.,
Dalton Trans. 2001, 923–927.
S. Gendler, S. Segal, I. Goldberg, Z. Goldschmidt, M. Kol,
Inorg. Chem. 2006, 45, 4783–4790.
B. J. O’Keefe, L. E. Breyfogle, M. A. Hillmyer, W. B. Tolman,
J. Am. Chem. Soc. 2002, 124, 4384–4393.
L.-C. Liang, F.-Y. Chen, M.-H. Huang, L.-C. Cheng, C.-W. Li,
H. M. Lee, Dalton Trans. 2010, 39, 9941–9951.
L.-C. Liang, Coord. Chem. Rev. 2006, 250, 1152–1177.
L.-C. Liang, W.-Y. Lee, C.-C. Yin, Organometallics 2004, 23,
3538–3547.
We thank the National Science Council of Taiwan for financial
support (NSC 99–2113-M-110–003-MY3 and 99–2119-M-110–
002), Mr. Ting-Shen Kuo (NTNU) for assistance with X-ray crys-
tallography, Ms. Ching-Wei Lu (NTU), Ms. I-Chuan Chen
(NCHU), and Ms. Chia-Chen Tsai (NCKU) for the elemental
analysis, Ms. Chao-Lien Ho (NSYSU), Ms. Mei-Yueh Chien
(NCHU), and Ms. Ru-Rong Wu (NCKU) for assistance with
NMR spectrosocpy, and the National Center for High-perform-
ance Computing (NCHC) for access to chemical databases. We are
also grateful to the reviewers for insightful comments.
[32]
[33]
[34]
L.-C. Liang, P.-S. Chien, M.-H. Huang, Organometallics 2005,
24, 353–357.
[35]
[36]
P.-S. Chien, L.-C. Liang, Inorg. Chem. 2005, 44, 5147–5151.
L.-C. Liang, M.-H. Huang, C.-H. Hung, Inorg. Chem. 2004,
43, 2166–2174.
L.-C. Liang, P.-S. Chien, Y.-L. Huang, J. Am. Chem. Soc. 2006,
128, 15562–15563.
L.-C. Liang, J.-M. Lin, W.-Y. Lee, Chem. Commun. 2005, 2462–
2464.
L.-C. Liang, J.-M. Lin, C.-H. Hung, Organometallics 2003, 22,
3007–3009.
M.-H. Huang, L.-C. Liang, Organometallics 2004, 23, 2813–
2816.
L.-C. Liang, P.-S. Chien, J.-M. Lin, M.-H. Huang, Y.-L. Hu-
ang, J.-H. Liao, Organometallics 2006, 25, 1399–1411.
L.-C. Liang, W.-Y. Lee, T.-L. Tsai, Y.-L. Hsu, T.-Y. Lee, Dalton
Trans. 2010, 39, 8748–8758.
[1] M. Vert, Macromol. Symp. 2000, 153, 333–342.
[2] R. E. Drumright, P. R. Gruber, D. E. Henton, Adv. Mater.
2000, 12, 1841–1846.
[3] B. J. O’Keefe, M. A. Hillmyer, W. B. Tolman, J. Chem. Soc.,
Dalton Trans. 2001, 2215–2224.
[4] O. Dechy-Cabaret, B. Martin-Vaca, D. Bourissou, Chem. Rev.
2004, 104, 6147–6176.
[37]
[38]
[39]
[40]
[41]
[42]
[43]
[5] J.-C. Wu, T.-L. Yu, C.-T. Chen, C.-C. Lin, Coord. Chem. Rev.
2006, 250, 602–626.
[6] C. A. Wheaton, P. G. Hayes, B. J. Ireland, Dalton Trans. 2009,
4832–4846.
[7] A. K. Sutar, T. Maharana, S. Dutta, C.-T. Chen, C.-C. Lin,
Chem. Soc. Rev. 2010, 39, 1724–1746.
[8] Y.-L. Hsu, L.-C. Liang, Organometallics 2010, 29, 6201–6208.
[9] Y.-N. Chang, L.-C. Liang, Inorg. Chim. Acta 2007, 360, 136–
142.
L.-C. Liang, W.-Y. Lee, C.-H. Hung, Inorg. Chem. 2003, 42,
5471–5473.
[10] M. H. Chisholm, N. W. Eilerts, Chem. Commun. 1996, 853–
854.
[44]
[45]
H. Staudinger, J. Meyer, Helv. Chim. Acta 1919, 2, 635–646.
T. S. Pilyugina, R. R. Schrock, A. S. Hock, P. Muller, Organo-
metallics 2005, 24, 1929–1937.
S. Al-Benna, M. J. Sarsfield, M. Thornton-Pett, D. L. Ormsby,
P. J. Maddox, P. Bres, M. Bochmann, J. Chem. Soc., Dalton
Trans. 2000, 4247–4257.
S. Murata, S. Abe, H. Tomioka, J. Org. Chem. 1997, 62, 3055–
3061.
K. D. Conroy, W. E. Piers, M. Parvez, J. Organomet. Chem.
2008, 693, 834–846.
G. C. Welch, W. E. Piers, M. Parvez, R. McDonald, Organome-
tallics 2004, 23, 1811–1818.
[11] M. H. Chisholm, N. W. Eilerts, J. C. Huffman, S. S. Iyer, M.
Pacold, K. Phomphrai, J. Am. Chem. Soc. 2000, 122, 11845–
11854.
[12] M. H. Chisholm, J. Gallucci, K. Phomphrai, Inorg. Chem.
2002, 41, 2785–2794.
[13] B. M. Chamberlain, M. Cheng, D. R. Moore, T. M. Ovitt,
E. B. Lobkovsky, G. W. Coates, J. Am. Chem. Soc. 2001, 123,
3229–3238.
[46]
[47]
[48]
[49]
[50]
[14] M. Cheng, A. B. Attygalle, E. B. Lobkovsky, G. W. Coates, J.
Am. Chem. Soc. 1999, 121, 11583–11584.
[15] H.-Y. Chen, B.-H. Huang, C.-C. Lin, Macromolecules 2005, 38,
5400–5405.
[16] C. M. Silvernail, L. J. Yao, L. M. R. Hill, M. A. Hillmyer, W. B.
Tolman, Inorg. Chem. 2007, 46, 6565–6574.
L. Bourget-Merle, M. F. Lappert, J. R. Severn, Chem. Rev.
2002, 102, 3031–3066.
2956
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 2948–2957

ROP Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands
[51] M. Cheng, D. R. Moore, J. J. Reczek, B. M. Chamberlain, E. B.
Lobkovsky, G. W. Coates, J. Am. Chem. Soc. 2001, 123, 8738–
8749.
[52] J. Prust, A. Stasch, W. J. Zheng, H. W. Roesky, E. Alexopoulos,
I. Uson, D. Bohler, T. Schuchardt, Organometallics 2001, 20,
3825–3828.
[60] M. H. Chisholm, J. C. Gallucci, K. Phomphrai, Inorg. Chem.
2005, 44, 8004–8010.
[61] A. P. Dove, V. C. Gibson, E. L. Marshall, A. J. P. White, D. J.
Williams, Dalton Trans. 2004, 570–578.
[62] D. R. Moore, M. Cheng, E. B. Lobkovsky, G. W. Coates, J.
Am. Chem. Soc. 2003, 125, 11911–11924.
[63] Y. Sarazin, M. Schormann, M. Bochmann, Organometallics
2004, 23, 3296–3302.
[53] M. S. Hill, P. B. Hitchcock, J. Chem. Soc., Dalton Trans. 2002,
4694–4702.
[54] M. D. Hannant, M. Schormann, M. Bochmann, J. Chem. Soc.,
Dalton Trans. 2002, 4071–4073.
[64] M. Save, M. Schappacher, A. Soum, Macromol. Chem. Phys.
2002, 203, 889–899.
[65] M. Haddad, M. Laghzaoui, R. Welter, S. Dagorne, Organome-
tallics 2009, 28, 4584–4592.
[66] Conversion of ca. 90% in 1 h for Entry 11.
[67] A. L. Spek, PLATON – A Multipurpose Crystallographic Tool,
Utrecht University, The Netherlands, 2003.
Received: December 29, 2010
[55] M. D. Hannant, M. Schormann, D. L. Hughes, M. Bochmann,
Inorg. Chim. Acta 2005, 358, 1683–1691.
[56] C. A. Wheaton, P. G. Hayes, Dalton Trans. 2010, 39, 3861–
3869.
[57] M. H. Chisholm, J. C. Huffman, K. Phomphrai, J. Chem. Soc.,
Dalton Trans. 2001, 222–224.
[58] M. Cheng, E. B. Lobkovsky, G. W. Coates, J. Am. Chem. Soc.
1998, 120, 11018–11019.
Published Online: May 25, 2011
[59] L. R. Rieth, D. R. Moore, E. B. Lobkovsky, G. W. Coates, J.
Am. Chem. Soc. 2002, 124, 15239–15248.
Eur. J. Inorg. Chem. 2011, 2948–2957
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2957