Reactivity of (3-Iminophosphine)palladium(II) complexes: evidence of hemilability

Article abstract of DOI:10.1021/om900066t

palladium(II) 3-iminophosphine complexes were synthesized in moderate to high yield. With relevance to many palladium-catalyzed coupling reactions, these complexes incorporate a wide variety of ligands, including amines, alkyls, allyls, and triflates. The

Full text of DOI:10.1021/om900066t

2494
Organometallics 2009, 28, 2494–2504
Reactivity of (3-Iminophosphine)palladium(II) Complexes: Evidence
of Hemilability
Andrew R. Shaffer and Joseph A. R. Schmidt*
Department of Chemistry, The UniVersity of Toledo, 2801 W. Bancroft St. MS 602,
Toledo, Ohio 43606-3390
ReceiVed January 28, 2009
Several palladium(II) 3-iminophosphine complexes were synthesized in moderate to high yield. With
relevance to many palladium-catalyzed coupling reactions, these complexes incorporate a wide variety
of ligands, including amines, alkyls, allyls, and triflates. The presence of both η1- and η2-coordination
modes demonstrates the hemilability of the 3-iminophosphine ligand class, as determined by X-ray
crystallography and NMR spectroscopy.
In an effort to couple the stability and reactivity of palladium
complexes with the benefits of a robust hemilabile ligand
framework, we recently reported the development of a new class
of chelating ligands known as 3-iminophosphines (3IP).9 These
ligands have significant electronic asymmetry, utilizing a soft
tertiary phosphine that exhibits a high affinity for palladium in
tandem with a much more weakly coordinating aldimine. The
difference in binding strength of these donor atoms makes these
ligands likely candidates to display hemilability within their
reaction manifolds. Palladium complexes have been shown to
be effective catalysts for the hydroamination of alkenes, alkynes,
and dienes.9-29 Despite the significant work done in this field,
a general mechanism for hydroamination via a group 10 catalyst
Introduction
In the last century, research involving palladium has revealed
an amazingly diverse reactivity for this metal. With access to
reaction pathways involving oxidative addition, reductive
elimination, insertion, transmetalation, and ꢀ-elimination (hy-
dride, carbon, or other heteroatoms), palladium proves to be
among the most versatile of transition metals.1 Furthermore,
palladium complexes have shown broad utility in catalytic
coupling reactions and are often tolerant to a wide range of
substrate functional groups.1 This balance of stability and
reactivity is ideal for building a catalyst system. Thus far, a
wide variety of palladium catalysts have been developed and
commercialized.2 The primary limitations of currently available
palladium catalysts involve electronic factors, often reducing
substrate scope. This difficulty is not due to catalyst instability,
but is a result of both catalytic activity (kinetics) and selectivity.
In an effort to improve existing catalyst technology while
broadening substrate applicability, our research has focused on
the development of new palladium-based catalyst systems.
For over a decade, it has been recognized that ligands capable
of hemilability play a special role in catalysis.3-8 The term
hemilability refers to a chelating ligand’s ability to partially
decoordinate from a metal center, freeing binding sites for
further reactivity while remaining attached to the transition
metal. This can be especially useful in stabilizing catalytic
intermediates, as the proximity of the ligand’s unutilized donor
atoms can help to prevent decomposition of highly reactive
intermediates within a catalytic cycle. Key aspects in the design
of hemilabile ligands include reduced ligand symmetry and steric
or electronic factors that favor one donor atom over another
within the ligand framework.
(9) Shaffer, A. R.; Schmidt, J. A. R. Organometallics 2008, 27, 1259–
1266.
(10) Kadota, I.; Shibuya, A.; Lutete, L. M.; Yamamoto, Y. J. Org. Chem.
1999, 64, 4570–4571.
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207.
(12) Kawatsura, M.; Hartwig, J. F. J. Am. Chem. Soc. 2000, 122, 9546–
9547.
(13) Muller, T. E.; Grosche, M.; Herdtweck, E.; Pleier, A. K.; Walter,
E.; Yan, Y. K. Organometallics 2000, 19, 170–183.
(14) Pohlki, F.; Doye, S. Chem. Soc. ReV. 2003, 32, 104–114.
(15) Lutete, L. M.; Kadota, I.; Yamamoto, Y. J. Am. Chem. Soc. 2004,
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(16) Jimenez, O.; Muller, T. E.; Sievers, C.; Spirkl, A.; Lercher, J. A.
Chem. Commun. 2006, 2974–2976.
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Soc. 2006, 128, 9306–9307.
(18) Johns, A. M.; Utsunomiya, M.; Incarvito, C. D.; Hartwig, J. F.
J. Am. Chem. Soc. 2006, 128, 1828–1839.
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4247.
(20) Sakai, N.; Ridder, A.; Hartwig, J. F. J. Am. Chem. Soc. 2006, 128,
8134–8135.
(21) Fustero, S.; Fernandez, B.; Bello, P.; del Pozo, C.; Arimitsu, S.;
Hammond, G. B. Org. Lett. 2007, 9, 4251–4253.
(22) Houghton, J.; Dyson, G.; Douthwaite, R. E.; Whitwood, A. C.;
Kariuki, B. M. Dalton Trans. 2007, 3065–3073.
(23) Johns, A. M.; Liu, Z. J.; Hartwig, J. F. Angew. Chem., Int. Ed.
2007, 46, 7259–7261.
* Corresponding author. E-mail: Joseph.Schmidt@utoledo.edu.
(1) Tsuji, J. Palladium Reagents and Catalysts; John Wiley & Sons:
Chichester, West Sussex, England, 2004.
(2) Elschenbroich, C. In Organometallics, 3rd ed.; Wiley-VCH: Wein-
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10.1021/om900066t CCC: $40.75
2009 American Chemical Society
Publication on Web 04/02/2009

(3-Iminophosphine)palladium(II) Complexes
Organometallics, Vol. 28, No. 8, 2009 2495
Scheme 1. Metal Complexationa
remains ambiguous. One plausible mechanism entails the
presence of a palladium-amido intermediate, with a rate-
determiningsteplikelyinvolvingthebreakageofanitrogen-hydrogen
bond. Alternatively, Hartwig and co-workers have suggested a
catalytic cycle utilizing a metal-hydride intermediate with
nucleophilic attack of an allylic species by an amine as the rate-
limiting step.30,31 Intriguingly, in our initial report, we note that
the hydroamination catalysis observed displays reactivity trends
that are orthogonal to those observed in Hartwig’s study.9
Specifically, the correlation between amine basicity and catalytic
activity observed was inverse to what had been previously
reported. Given the uniqueness of our system, we set out to
produce a series of target palladium complexes relevant to the
study of this hydroamination mechanism and, moreover, to
investigate the stoichiometric reactivity of these new 3-imino-
phosphine palladium complexes.
a
(i) PdX2 (X ) Cl (2), Br (3)), CH3CN, 14 h. (ii) 0.5 [(allyl)PdCl]2,
CH2Cl2, 14 h. (iii) AgOTf, CH2Cl2, 2 h; or Li[B(C6F5)4], Et2O, 14 h;
or NH4PF6, CH2Cl2, 14 h; Y ) OTf (5a), B(C6F5) (5b), PF6 (5c).
(4) was found to contain an η1-3IP ligand coordinated through
its phosphorus donor atom, with the remainder of the pal-
ladium’s coordination sphere fulfilled by chloro and η3-allyl
ligands.9 Treatment of 4 with silver triflate readily produced
[(3IP)Pd(allyl)][OTf] (5a), containing an η2-3IP ligand and an
outer-sphere triflate ligand.9 In a similar fashion, the reaction
of 4 with Li[B(C6F5)4] also results in salt elimination and the
formation of [(3IP)Pd(allyl)][B(C6F5)4] (5b). On the basis of
the strong similarities in the NMR spectra, we postulate an
analogous coordination environment at the palladium center in
this complex. We have recently found a more attractive route
to similar complexes through the treatment of 4 with ammonium
salts.32,33 The reaction of 4 with ammonium hexafluorophos-
phate yielded the ionic species [(3IP)Pd(allyl)][PF6] (5c)
(Scheme 1). Again, similar NMR shifts were observed for 5c;
however, two isomers were present in a 10:3 ratio. These
isomers were a result of the geometric arrangement of the allylic
substituent with respect to the cyclopentenyl ring. The allyl
group can be considered to point in a certain direction, as
indicated by the CfH vector of its central carbon atom. In
addition, the five-membered chelate ring of the 3IP ligand is
not planar, but rather puckered with the cyclopentenyl ring
centered above or below the palladium coordination plane. Thus,
two distinct isomers exist, denoted cis and trans, indicating that
the CfH vector and the cyclopentenyl ring are on the same or
opposite sides of the square plane of palladium coordination.
The isomer assignment was supported by 2D NMR experiments.
The solid state structure of 5c was obtained and revealed that
the two distinctive isomers cocrystallized, confirming these
conclusions (Figure 1).
Results and Discussion
As a means to initiate a detailed study into the mechanism
of hydroamination using 3-iminophosphine palladium species,
we first set out to synthesize and isolate several discrete
complexes bearing substituents that were plausible intermediates
in its catalytic cycles. Additionally, due to the reasonably weak
bonding of imines to palladium, we hypothesized that hemilabile
characteristics in this ligand set could play a very important
role in its chemistry. Thus, we investigated relevant reactions
targeted at establishing the hemilabile nature of the 3-imino-
phosphine ligand set. Herein, the synthesis of several palla-
dium(II) complexes using classical organometallic routes from
commercially available palladium(II) sources is presented. In
general, these complexes were produced in moderate yields by
first coordination of a 3-iminophosphine ligand to a palla-
dium(II) precursor, followed by an alkylation and/or salt
metathesis reaction to yield the functionalized palladium
complexes. The resulting species are potentially useful as
precatalysts for a variety of palladium-catalyzed coupling
reactions, including the intermolecular hydroamination of
unsaturated carbon-carbon bonds. In this contribution, we focus
exclusively on the synthesis and isolation of a wide variety of
functionalized 3-iminophosphine palladium(II) complexes.
We presented the synthesis of the 3-iminophosphine ligand
(1) used throughout this work previously.9 The coordination
complexes (3IP)PdX2 (2 and 3) were readily produced by
reacting 1 equiv of anhydrous PdX2, where X ) Cl (2) or Br
(3), with an equimolar amount of 1 (Scheme 1). The chloro
complex (2) displayed η2-ligand coordination, as evident by the
upfield shift of the imine proton and downfield shift of the
phosphorus resonance and was confirmed by X-ray crystal-
lography.9 The related bromo complex (3) showed similar NMR
resonances to that of 2, consistent with η2 ligation. An alternate
route to 3 involved the reaction of 2 with 2 equiv of lithium
bromide. This reaction proceeded rapidly with quantitative
conversion of 2 to 3. The driving force for this reaction likely
derives from the high lattice energy of the byproduct, lithium
chloride, as well as improved orbital overlap between the
palladium and the bromide ligands compared to that observed
with chloride ligands.
Given that 5a was previously shown to be active for the
catalytic hydroamination of dienes and alkynes,9 we were
curious about the affinity of 3IP complexes for amine ligands.
Specifically, we sought to establish a positive correlation
between amine coordination to the palladium center and catalytic
activity. As a means to probe this, we investigated the reactions
of complex 2 with a wide variety of primary and secondary
amines. Also, this amine coordination could be an important
step in the mechanism for catalytic aryl amination.34 Therefore,
a variety of amines were reacted with 2 to yield the correspond-
ing (3IP)PdCl2(amine) complexes (6a-l) (Scheme 2). The
reaction proceeded readily in almost any solvent, including
The 3IP ligand also readily coordinates to palladium supplied
as the (allyl)palladium chloride dimer.9 The resulting complex
(32) Nama, D.; Butti, P.; Pregosin, P. S. Organometallics 2007, 26,
4942–4954.
(30) Pawlas, J.; Nakao, Y.; Kawatsura, M.; Hartwig, J. F. J. Am. Chem.
Soc. 2002, 124, 3669–3679.
(31) Nettekoven, U.; Hartwig, J. F. J. Am. Chem. Soc. 2002, 124, 1166–
1167.
(33) Aznar, R.; Muller, G.; Sainz, D.; Font-Bardia, M.; Solans, X.
Organometallics 2008, 27, 1967–1969.
(34) Strieter, E. R.; Blackmond, D. G.; Buchwald, S. L. J. Am. Chem.
Soc. 2003, 125, 13978–13980.

2496 Organometallics, Vol. 28, No. 8, 2009
Shaffer and Schmidt
Figure 2. ORTEP diagram (50% thermal ellipsoids) of 6a. Other
than the amine, hydrogen atoms have been omitted for clarity. Bond
lengths (in Å): Pd1-P1 ) 2.246(1), Pd1-Cl1 ) 2.298(1), Pd1-Cl2
) 2.306(1), Pd1-N2 ) 2.211(2), N1-C1 ) 1.267(3), C1-C2 )
1.460(3), C2-C3 ) 1.338(3), N2-C24 ) 1.479(3), N2-C25 )
1.476(3). Bond angles (in deg): P1-Pd1-N2 ) 177.0(1),
P1-Pd1-Cl1 ) 95.3(1), P1-Pd1-Cl2 ) 86.6(1), Cl1-Pd1-Cl2
) 177.4(1), N1-C1-C2 ) 121.3(2), C1-C2-C3 ) 126.8(2),
C2-C3-P1 ) 124.1(2), C23-C24-N2 ) 111.9(2), C24-N2-C25
) 111.2(2), N2-C25-C26 ) 111.9(2).
Figure 1. ORTEP diagram (50% thermal ellipsoids) of the cationic
portions of 5c. The central carbon of the allyl group bound to Pd1
is disordered over two positions in a 1:1 ratio, giving a 1:1 ratio of
cis/trans isomers in this half of the asymmetric unit. Hydrogen
atoms and hexafluorophosphate ions have been omitted for clarity.
Bond lengths (in Å): Pd1-P1 ) 2.267(2), Pd1-N1 ) 2.160(5),
Pd2-P2 ) 2.262(2), Pd2-N2 ) 2.144(6). Bond angles (in deg):
P1-Pd1-N1 ) 90.2(1), P2-Pd2-N2 ) 87.7(2).
Scheme 2. Amine Coordinationa
Scheme 3. Salt Metathesis of 2a
a
a
HNRR′ ) diethylamine (6a), morpholine (6b), piperidine (6c),
X ) Cl (2, 7), Br (3, 8).
N-methylbutylamine (6d), di-n-butylamine (6e), dibenzylamine (6f),
pyrrolidine (6g), diisopropylamine (6h), cyclohexylamine (6i), tert-
butylamine (6j), p-toluidine (6k), or benzylamine (6l).
diethylaniline, the lower basicity, coupled to its extensive steric
bulk, completely prohibits its coordination.
chloroform, dichloromethane, tetrahydrofuran, diethyl ether, and
toluene; however, the reaction rate is correlated to the solubility
of the initial palladium complex in the reaction solvent. The
observed NMR spectra were suggestive of η1 coordination by
the 3IP ligand in the product complexes, as evidenced by the
significant downfield shift of the imine proton, while the
phosphorus shift moved only slightly upfield. The solid state
structure of 6a confirmed the suspected coordination environ-
ment of the palladium, revealing trans chloride ligands, a
coordinated diethylamine, and the η1-3IP ligand bound only
through the phosphorus donor atom (Figure 2). Ultimately, it
was found that this reaction was general to virtually every amine
tested, and so a series of these complexes with differing
electronic and steric properties were synthesized, all displaying
similar NMR shifts. In general, for aliphatic amines, coordina-
tion appeared to be independent of amine basicity and steric
bulk. It is perhaps most revealing to discuss those amines that
did not undergo this reaction readily, specifically aryl amines.
Two representative aryl amines, p-toluidine and 2,6-diethyla-
niline, were used to investigate this coordination reaction. The
coordination of p-toluidine proceeded very slowly, only achiev-
ing 51% completion, even after extensive heating at 100 °C.
No reaction at all was observed for 2,6-diethylaniline even when
the reaction was heated to 60 °C for several days. The reduced
basicity of these aryl amines clearly hampers their ability to
coordinate to the palladium center. In the case of the 2,6-
Next, we set out to produce a set of highly electrophilic
(3IP)Pd(II) complexes for future catalytic screening. The
synthesis of a monochloro, monotriflato palladium complex (7)
was achieved by the reaction of 2 with 1 equiv of silver triflate
(Scheme 3). This reaction proceeds through a standard salt
metathesis reaction pathway, where the silver cation removes a
chloride from the palladium. There are significant downfield
1
shifts in the H NMR spectrum for all the protons except for
those associated with the methylene bridge of the cyclopentenyl
ring. Moreover, the phosphorus resonance is also shifted
downfield significantly. The solid state structure of 7 revealed
a dimer with two chlorides bridging two palladium centers, along
with two outer-sphere triflate anions (Figure 3).35 The analogous
monobromo, monotriflato palladium complex (8) was synthe-
sized in a similar fashion and displayed very similar spectro-
scopic data to that of 7, consistent with a similar dimeric
structure. To further enhance the electrophilicity of these
complexes, we replaced the remaining halide ligand with another
triflate counterion. Amazingly, the resultant complex proved to
(35) Dicationic palladium dimers bridged by chloride ligands with outer-
sphere triflate anions have been observed previously: (a) Devic, T.; Batail,
P.; Fourmigue, M.; Avarvari, N. Inorg. Chem. 2004, 43, 3136–3141. (b)
Fairlamb, I. J. S.; Grant, S.; Tommasi, S.; Lynam, J. M.; Bandini, M.; Dong,
H.; Lin, Z. Y.; Whitwood, A. C. AdV. Synth. Catal. 2006, 348, 2515–2530.
(c) Leone, A.; Gischig, S.; Consiglio, G. J. Organomet. Chem. 2006, 691,
4816–4828.

(3-Iminophosphine)palladium(II) Complexes
Organometallics, Vol. 28, No. 8, 2009 2497
Figure 3. ORTEP diagram (50% thermal ellipsoids) of the cationic
portion of 7. Hydrogen atoms, disordered tBu carbon atoms, CH2Cl2
molecule, and triflate ions have been omitted for clarity. Bond
lengths (in Å): Pd1-P1 ) 2.215(2), Pd1-N1 ) 2.080(5), Pd-Cl1
) 2.326(2), Pd1-Cl2 ) 2.468(2), Pd2-P2 ) 2.020(2), Pd2-N2
) 2.045(5), Pd2-Cl1 ) 2.446(2), Pd2-Cl2 ) 2.327(2). Bond
angles (in deg): P1-Pd1-N1 ) 89.4(1), P1-Pd1-Cl1 ) 89.9(1),
P1-Pd1-Cl2 ) 165.6(1), N1-Pd1-Cl1 ) 172.7(1), N1-Pd1-Cl2
) 99.4(1), P2-Pd2-N2 ) 88.3(2), P2-Pd2-Cl1 ) 166.1(1),
P2-Pd2-Cl2 ) 93.0 (1), N2-Pd2-Cl1 ) 97.1(2), N2-Pd2-Cl2
) 172.7(2).
Figure 4. ORTEP diagram (50% thermal ellipsoids) of 9. Hydrogen
atoms have been omitted for clarity. Bond lengths (in Å): Pd1-P1
) 2.194(1), Pd1-N1 ) 2.016(2), Pd1-O1 ) 2.155(2), Pd1-O4
) 2.064(2), N1-C1 ) 1.288(3), C1-C2 ) 1.452(3), C2-C3 )
1.341(3).Bondangles(indeg):P1-Pd1-N1)86.1(1),P1-Pd1-O1
) 174.4(1), P1-Pd1-O4 ) 92.4(1), O1-Pd1-O4 ) 86.9(1),
O1-Pd1-N1 ) 94.7(1), N1-C1-C2 ) 125.7(2), C1-C2-C3 )
125.0(2), C2-C3-P1) 120.2(2).
Scheme 4. Alkylation of 2a
be isolable, with no evidence of decomposition to palladium
black or other likely byproducts. The product, (3IP)Pd(OTf)2
(9), can be synthesized by either adding 1 equiv of silver triflate
to 7 or adding 2 equiv to 2. Initially, we noted that 9 had very
similar NMR resonances to 2, which was suggestive of a similar
coordination environment. To confirm this assertion, X-ray
quality crystals were grown and the solid state structure
confirmed the η2 coordination of the 3-iminophosphine ligand
as well as two inner-sphere triflate anions (Figure 4).36
The versatility and stability of halogenated palladium(II)
compounds are excellent attributes for their synthesis and
isolation. However, we expect that the incorporation of triflate
anion(s) will enhance the reactivity of the 3IP-palladium
complexes because of the increased electrophilicity of the metal,
which allows for stronger binding to substrates. Moreover, we
suspect that compound 9 will display similar amine coordination
chemistry to that of compound 2, although it is unclear how
the amine binding will affect the coordination environment of
the palladium. The investigation of this amine coordination
chemistry remains a topic of current pursuit in our laboratory.
One final class of compounds of interest herein are those in
which palladium-alkyl bonds are present. Palladium-alkyl
complexes are relevant to a wide variety of cross-coupling
reactions commonly catalyzed by palladium species.1,37-40 In
addition, palladium-alkyls often undergo insertion reactions,
leading to the production of alternative functional groups such
asacylsandcarboxylates.1Moreover,theweakerpalladium-carbon
bond is more susceptible to cleavage than the corresponding
palladium-chloride bond. Alkylation of 2 was readily achieved
using two different synthetic routes (Scheme 4). (3IP)Pd(CH3)Cl
a
(i) Sn(CH3)4, CH2Cl2, 30 h or CH3Li, THF, -78°C f 22°C, 14 h.
(10) was synthesized by reacting 2 with either methyllithium
or tetramethyltin. The appearance of a doublet in the 1H NMR
spectrum, as well as a significant shift in the phosphorus
resonance, was indicative of alkylation. Also, the imine proton
displayed a chemical shift less than 8.00 ppm, suggestive of η2
coordination. The solid state structure of 10 confirmed the η2
coordination of the 3-iminophosphine ligand and showed that
the methyl group was located trans to the nitrogen donor atom
(Figure 5). In contrast, when the methylating agent used was
methyllithium complexed with lithium bromide, an anion
exchange was observed, ultimately leading to the isolation of
(3IP)Pd(CH3)Br (11). A more straightforward synthesis of 11
was achieved similarly by reacting 3 with either methyllithium
or tetramethyltin (Scheme 5). Furthermore, 11 was also produced
by the reaction of 10 with 1 equiv of lithium bromide, which is
believed to be the reaction that occurs if methylation of 2 is
attempted with methyllithium complexed with lithium bromide.
These reaction pathways are very similar to the alternative
synthesis of 3 from 2 using lithium bromide. With these
alkylated species isolated, our final goal was to combine the
traits of the alkyl complexes with weakly coordinating coun-
terions to produce a highly electrophilic palladium-alkyl
(37) Wolfe, J. P.; Wagaw, S.; Marcoux, J. F.; Buchwald, S. L. Acc.
Chem. Res. 1998, 31, 805–818.
(38) Penn, L.; Shpruhman, A.; Gelman, D. J. Org. Chem. 2007, 72,
3875–3879.
(39) Scrivanti, A.; Bertoldini, M.; Matteoli, U.; Beghetto, V.; Antonaroli,
S.; Marini, A.; Crociani, B. J. Mol. Catal. A: Chem. 2005, 235, 12–16.
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Cadierno, V.; Donnadieu, B.; Igau, A.; Caminade, A. M.; Majoral, J. P.
Organometallics 2002, 21, 4680–4687.
(36) Similar structural motifs have been observed in reports employing
diphosphine ligands: (a) Anandhi, U.; Holbert, T.; Lueng, D.; Sharp, P. R.
Inorg. Chem. 2003, 42, 1282–1295. (b) Corkey, B. K.; Toste, F. D. J. Am.
Chem. Soc. 2005, 127, 17168–17169. (c) Monguchi, D.; Beemelmanns, C.;
Hashizume, D.; Hamashima, Y.; Sodeoka, M. J. Organomet. Chem. 2008,
693, 867–873.

2498 Organometallics, Vol. 28, No. 8, 2009
Shaffer and Schmidt
Figure 5. ORTEP diagram (50% thermal ellipsoids) of 10.
Hydrogen atoms have been omitted for clarity. Bond lengths (in
Å): Pd1-P1 ) 2.196(1), Pd1-N1 ) 2.212(2), Pd1-Cl1 )
2.389(1), Pd1-C23 ) 2.034(2), N1-C1 ) 1.274(3), C1-C2 )
1.463(3), C2-C3 ) 1.346(3). Bond angles (in deg): P1-Pd1-N1
) 84.9(1), P1-Pd1-C23 ) 93.3(1), C23-Pd1-Cl1 ) 87.3(1),
Cl1-Pd1-N1 ) 95.1(1), N1-C1-C2 ) 124.8(2), C1-C2-C3
) 126.4(2), C2-C3-P1 ) 121.3(2).
Figure 6. ORTEP diagram (50% thermal ellipsoids) of 12.
Hydrogen atoms have been omitted for clarity. Bond lengths (in
Å): Pd1-P1 ) 2.173(1), Pd1-N1 ) 2.188(2), Pd1-O1 ) 2.182(2),
Pd1-C23 ) 2.022(3), N1-C1 ) 1.281(4), C1-C2 ) 1.461(4),
C2-C3 ) 1.336(4). Bond angles (in deg): P1-Pd1-N1 ) 87.9(1),
P1-Pd1-C23 ) 91.3(1), P1-Pd1-O1 ) 172.5(1), C23-Pd1-O1
) 86.9(1), O1-Pd1-N1 ) 94.3(91), N1-C1-C2 ) 125.3(3),
C1-C2-C3 )126.7(2), C2-C3-P1 ) 123.6(2).
Scheme 5. Synthesis of 11
complex. Substitution of the chloride for a weakly coordinating
triflate anion was accomplished by reacting 10 with 1 equiv of
silver triflate in a standard salt metathesis reaction to produce
(3IP)Pd(Me)OTf (12) (Scheme 4). The NMR assignment of the
observed resonances was consistent with η2 coordination of the
ligand and showed very little shift in the resonance associated
with the methyl bound to the palladium center. Therefore, it
was determined that the triflate was coordinated to the palladium
center, and the solid state crystal structure confirmed that
assessment (Figure 6).41
As shown above, 3IP ligands adopt η1 or η2 coordination
dependent on the coordinative requirements of the palladium
center. Clearly, the imine is a much weaker donor atom than
the phosphorus in this type of ligand. We hypothesize that the
hemilabile nature of this ligand plays a key role in the catalytic
activity previously displayed by its palladium complexes.9
Interestingly, we found that the solid state structure of compound
11 depends on the recrystallization solvents used, where two
distinct structures were observed. Crystals that yielded a
monomeric solid state structure with an η2-3IP ligand (Figure
7) were produced from a layered solution of CH2Cl2 and Et2O.
This monomeric structure is completely isomorphous to that
observed for 10, its chloro counterpart. However, when the solid
state structure was obtained from crystals produced from a
Figure 7. ORTEP diagram (50% thermal ellipsoids) of 11a.
Hydrogen atoms have been omitted for clarity. Bond lengths (in
Å): Pd1-P1 ) 2.208(1), Pd1-N1 ) 2.154(4), Pd1-Br1 )
2.530(1), Pd1-C23 ) 2.087(6), N1-C1 ) 1.275(6), C1-C2 )
1.463(6), C2-C3 ) 1.344(7). Bond angles (in deg): P1-Pd1-N1
) 85.8(1), P1-Pd1-C23 ) 93.9(2), P1-Pd1-Br1 ) 164.4(1),
Br1-Pd1-C23 ) 87.9(2), Br1-Pd1-N1 ) 94.7(1), N1-C1-C2
) 125.2(4), C1-C2-C3 ) 125.6(5), C2-C3-P1 ) 122.2(4).
layered solution of THF and pentane, the 3-iminophosphine
adopted an η1 coordination mode, binding to the palladium
through only the phosphorus atom, resulting in a dimeric
structure (Figure 8). The NMR spectra for each set of crystals
were identical, supporting that the hemilability of the 3-imino-
phosphine ligand is entirely solvent dependent. These results
represent the first evidence of hemilabile structural isomers in
3-iminophosphine palladium complexes and suggest that a
complex solution behavior is operable.
(41) Methylpalladium(II) complexes with inner-sphere triflate ligands
have been observed in several reports: (a) Burger, P.; Baumeister, J. M. J.
Organomet. Chem. 1999, 575, 214–222. (b) Burrows, A. D.; Mahon, M. F.;
Varrone, M. Dalton Trans. 2003, 4718–4730. (c) Scarel, A.; Durand, J.;
Franchi, D.; Zangrando, E.; Mestroni, G.; Carfagna, C.; Mosca, L.; Seraglia,
R.; Consiglio, G.; Milani, B. Chem.-Eur. J. 2005, 11, 6014–6023. (d)
Grotjahn, D. B.; Gong, Y.; Zakharov, L.; Golen, J. A.; Rheingold, A. L.
J. Am. Chem. Soc. 2006, 128, 438–453. (e) Yamashita, M.; Takamiya, I.;
Jin, K.; Nozaki, K J. Organomet. Chem. 2006, 691, 3189–3195. (f)
Yamashita, M.; Takamiya, I.; Jin, K.; Nozaki, K. Organometallics 2006,
25, 4588–4595. (g) Agostinho, M.; Braunstein, P. Chem. Commun. 2007,
58–60. (h) Agostinho, M.; Braunstein, P.; Welter, R. Dalton Trans. 2007,
759–770.
Conclusions
In this article, we described the synthesis and isolation of a
wide variety of 3-iminophosphine palladium complexes. Specif-
ically, we focused on compounds most relevant to catalytic
hydroamination and similar cross-coupling reactions. The

(3-Iminophosphine)palladium(II) Complexes
Organometallics, Vol. 28, No. 8, 2009 2499
1
and used without further purification. All H and 13C NMR data
were obtained on a 600 MHz Inova NMR spectrometer at ambient
temperature at 599.9 and 150.2 MHz, respectively. 31P and 19F NMR
data were obtained on a 400 MHz Varian NMR spectrometer at
1
ambient temperature at 161.9 and 376.3 MHz, respectively. H
NMR shifts are given relative to CHCl3 (7.26 ppm), and 13C NMR
shifts are given relative to CDCl3 (77.3 ppm). Phosphorus and
fluorine NMR were externally referenced to 0.00 ppm with 5%
H3PO4 in D2O and CFCl3, respectively. IR samples were prepared
as Nujol mulls and taken between KBr plates on a Perkin-Elmer
XTL FTIR spectrophotometer. Melting points were observed on a
capillary Mel-Temp apparatus in sealed capillary tubes under
nitrogen for compounds 5-12 and are uncorrected. Elemental
analyses were determined by Columbia Analytics, Tucson, AZ, and
Galbraith Laboratories, Knoxville, TN. Single-crystal X-ray struc-
ture determinations were performed at The University of Toledo.
Compounds 1, 2, 4, and 5a were prepared as described previously.9
Li[B(C6F5)4] was prepared according to literature.42,43
(3IP)PdBr2 (3). Method A: To a slurry of PdBr2 (0.442 g, 1.66
mmol) in acetonitrile (30 mL), a solution of 1 (0.613 g, 1.83 mmol)
in an acetonitrile/dichloromethane mixture (20 mL:5 mL) was
added, and the reaction was stirred at ambient temperature for 14 h.
Solvent was removed, and the red solid was washed with diethyl
ether (3 × 30 mL) to remove excess 1. The solid was dissolved in
dichloromethane and precipitated with diethyl ether (0.913 g,
91.3%); Method B: Lithium bromide (0.009 g, 0.1 mmol) and 2
(0.017 g, 0.033 mmol) were added to two vials in a drybox, CDCl3
was added to each, and the contents of the vials were mixed.
Quantitative formation of 3 was observed by 1H, 13C, and 31P NMR
Figure 8. ORTEP diagram (50% thermal ellipsoids) of 11b.
Hydrogen atoms have been omitted for clarity. Bond lengths (in
Å): Pd1-P1 ) 2.372(1), Pd1-Br1 ) 2.584(1), Pd1-Br1a )
2.656(1), Pd1-C23 ) 2.031(3), N1-C1 ) 1.225(4), C1-C2 )
1.585(4), C2-C3 ) 1.304(4). Bond angles (in deg): P1-Pd1-C23
) 94.0(1), P1-Pd1-Br1 ) 88.2(1), P1-Pd1-Br1a ) 178.2(1),
Br1-Pd1-Br1a ) 90.0(1), Br1-Pd1-C23 ) 177.7(1), N1-C1-C2
) 127.9(2), C1-C2-C3 ) 131.4(2), C2-C3-P1 ) 115.1(2).
Atoms labeled with an “a” are generated by an inversion symmetry
operator: -x, -y+1, -z+1.
1
spectroscopy; mp 185 °C (dec); H NMR δ 7.53-7.57 (m, 6H),
halogenated and alkylated palladium complexes synthesized
were readily converted to highly electrophilic complexes through
the use of weakly coordinating counterions. Additionally, we
demonstrated that these halide species have a strong affinity
for amine ligands. Numerous examples of both η1- and
η2-coordinated 3IP ligands support that hemilabile traits are quite
common in this ligand set. With these results, we continue to
investigate the catalytic mechanism involved in hydroamination
using our 3IP palladium complexes while applying these unique
catalysts to a wide variety of other cross-coupling reactions.
7.45-7.48 (m, 4H), 7.41 (s, 1H), 2.87-2.91 (m, 2H), 2.46-2.52
3
(m, 2H), 2.14 (pent, JHH ) 7.8 Hz, 2H), 1.43 (s, 9H); 13C{1H}
NMR δ 163.2 (d, 1JPC ) 73.5 Hz), 159.9 (d, 3JPC ) 9.5 Hz), 156.1
2
3
4
(d, JPC ) 15.3 Hz), 133.7 (d, JPC ) 11.0 Hz), 132.5 (d, JPC
)
2
1
2.9 Hz), 129.1 (d, JPC ) 11.9 Hz), 126.4 (d, JPC ) 56.5 Hz),
67.2, 37.1 (d, 3JPC ) 2.6 Hz), 36.6 (d, 2JPC ) 11.6 Hz), 32.2, 23.5
3
(d, JPC ) 6.4 Hz); 31P{1H} NMR δ 23.7; IR 2923 (s), 2850 (s),
2722 (w), 2676 (w), 1614 (w), 1578 (w), 1458 (m), 1371 (m), 1307
(w), 1271 (w), 1220 (w), 1183 (w), 1156 (w), 1097 (w), 1028 (w),
1000 (w), 987 (w), 890 (w), 744 (w), 689 (w). Anal. Calcd for
C22H26Br2NPPd · CH2Cl2: C, 40.24; H, 4.11; N, 2.04. Found: C,
39.85; H, 4.05; N, 1.90.
Experimental Section
[(3IP)Pd(allyl)][B(C6F5)4] (5b). To a stirring slurry of lithium
tetrakis(pentafluorophenyl)borate (0.354 g, 0.516 mmol) in diethyl
ether (20 mL) was added a solution of 4 (0.223 g, 0.430 mmol) in
diethyl ether (20 mL), and the mixture was stirred for 14 h. Solvent
was removed, resulting in a yellow powder, which was washed
with pentane (3 × 20 mL), dissolved in diethyl ether, and
General Considerations. Compounds 5-12 were prepared using
standard Schlenk and drybox techniques. Palladium(II) chloride,
palladium(II) bromide, (allyl)palladium(II) chloride dimer, meth-
yllithium complexed with lithium bromide (1.5 M in diethyl ether),
and silver triflate were purchased from Strem and used without
further purification. CDCl3 was purchased from Cambridge Isotope
Laboratories and for air-sensitive applications, was dried over
calcium hydride, freeze-pump-thawed three times, vacuum
transferred, and stored in a nitrogen atmosphere. All other solvents
were purchased from either VWR or Fisher. Pentane, toluene,
tetrahydrofuran, and dichloromethane were purified by passage
through a column of activated 4 Å molecular sieves and degassed
prior to use. Diethyl ether was purified by passage through a column
of activated alumina and degassed prior to use. Acetonitrile was
dried over calcium hydride at reflux, distilled and degassed with
nitrogen prior to use. NH4PF6 was purchased from Acros and used
without further purification. Diethylamine, dibenzylamine, mor-
pholine, piperidine, N-methyl-n-butylamine, di-n-butylamine, p-
toluidine, cyclohexylamine, tert-butylamine, pyrrolidine, di-
isopropylamine, benzylamine, and 2,6-diethylaniline used for
coordination reactions were purchased from Acros and dried over
by calcium hydride, freeze-pump-thawed three times, distilled,
and stored under nitrogen. Methyllithium (3.0 M in hexanes) and
tetramethyltin were purchased from Aldrich and used without
further purification. Lithium bromide was purchased from Fisher
1
precipitated with pentane (0.234 g, 46.8%); mp 147-148 °C; H
3
NMR δ 8.02 (s, 1H), 7.54 (t, JHH ) 7.8 Hz, 2H), 7.47 (pseudo t,
3JHH ) 8.4 Hz, 3JHH ) 7.8 Hz, 4H), 7.41 (dd, 3JPH ) 12.0 Hz, 3JHH
) 8.4 Hz, 4H), 5.57-5.64 (m, 1H), 4.93-4.96 (m, 1H), 3.77-3.81
(m, 1H), 2.82-2.96 (m, 4H), 2.51-2.55 (m, 2H), 2.01 (pseudo
3
3
pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.25 (s, 9H); 13C{1H}
NMR δ 154.3 (d, 3JPC ) 15.9 Hz), 151.6 (d, 2JPC ) 9.2 Hz), 149.2
1
(br s), 147.6 (br s), 137.3 (br s), 136.1 (d, JPC ) 34.0 Hz), 135.7
(br s), 134.0 (d, 1JPC ) 26.2 Hz), 132.9 (d, 2JPC ) 12.2 Hz), 132.2,
3
3
2
129.7 (d, JPC ) 11.0 Hz), 120.1 (d, JPC ) 6.0 Hz), 83.1 (d, JPC
2
) 27.9 Hz), 66.5, 57.4, 37.6 (d, JPC ) 9.9 Hz), 37.3, 29.8, 22.6
(d, 3JPC ) 6.2 Hz); 31P{1H} NMR δ 16.0; 19F{1H} NMR δ -133.0
3
3
(br s, 8F), -163.6 (t, JFF ) 18.4 Hz, 4F), -167.2 (br t, JFF
)
18.4 Hz, 8F); IR 2955 (s), 2914 (s), 2853 (s), 2731 (w), 2344 (w),
1760 (w), 1638 (w), 1582 (w), 1505 (m), 1454 (s), 1372 (m), 1300
(42) Lambert, J. B.; Zhang, S. Z.; Ciro, S. M. Organometallics 1994,
13, 2430–2443.
(43) Massay, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2, 245–
250.

2500 Organometallics, Vol. 28, No. 8, 2009
Shaffer and Schmidt
(w), 1259 (w), 1223 (w), 1187 (w), 1151 (w), 1084 (m), 1023 (w),
977 (m), 864 (w), 797 (w), 771 (w), 740 (w), 720 (w), 689 (w),
663 (w). Anal. Calcd for C49H31BF20NPPd: C, 50.64; H, 2.69; N,
1.21. Found: C, 50.97; H, 2.81; N, 1.18.
mmol). The solutions were allowed to stand for 10 min before the
spectra were obtained.
(3IP)PdCl2(HN(C2H4)2O) (6b). 1H NMR δ 8.89 (s, 1H),
7.72-7.76 (m, 4H), 7.44-7.46 (m, 2H), 7.36-7.39 (m, 4H), 3.86
(d, 3JHH ) 10.8 Hz, 4H), 3.33 (d, 3JPH ) 7.2 Hz, 1H), 3.01 (d, 3JHH
) 10.8 Hz, 4H), 2.90-2.93 (m, 2H), 2.52-2.55 (m, 2H), 1.90
[(3IP)Pd(allyl)][PF6] (5c). To a stirring slurry of ammonium
hexafluorophosphate (0.136 g, 0.833 mmol) in dichloromethane (20
mL), 4 (0.360 g, 0.694 mmol) in dichloromethane (20 mL) was
added, and the mixture was allowed to stir at ambient temperature
for 14 h. Solvent was removed, and the solid was washed with
diethyl ether to remove any unreacted 4, to yield a mixture of cis
and trans isomers in a 3:10 ratio as a yellow solid (0.436 g, 87.2%);
3
3
(pseudo pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.10 (s, 9H);
13C{1H} NMR δ 154.1 (d, JPC ) 6.9 Hz), 153.5 (d, JPC ) 9.4
2
3
1
3
Hz), 136.1 (d, JPC ) 46.8 Hz), 135.1 (d, JPC ) 10.6 Hz), 131.3
4
1
2
(d, JPC ) 2.8 Hz), 129.2 (d, JPC ) 57.2 Hz), 128.3 (d, JPC
)
4
3
11.4 Hz), 68.2 (d, JHH ) 3.2 Hz), 58.4, 48.2 (d, JPC ) 3.2 Hz),
1
4
3
2
mp 169-174 °C; cis isomer: H NMR δ 8.50 (d, JPH ) 3.0 Hz,
1H), 7.48-7.56 (m, 6H), 7.35-7.43 (m, 4H), 5.62-5.68 (m, 1H),
5.18-5.21 (m, 1H), 3.83-3.87 (m, 1H), 3.56-3.58 (m, 1H),
2.88-3.03 (m, 2H), 2.57-2.64 (m, 2H), 2.44-2.49 (m, 1H),
40.6 (d, JPC ) 5.8 Hz), 35.0 (d, JPC ) 12.3 Hz), 30.1, 22.8 (d,
3JPC ) 8.7 Hz); 31P{1H} NMR δ 16.7.
(3IP)PdCl2(HN(C5H10)) (6c). 1H NMR δ 8.90 (s, 1H), 7.72-7.76
(m, 4H), 7.42-7.45 (m, 2H), 7.35-7.38 (m, 4H), 3.22-3.24 (m,
2H), 3.12-3.16 (m, 2H), 3.04-3.10 (m, 1H), 2.89-2.92 (m, 2H),
2.50-2.54 (m, 2H), 1.89 (pseudo pent, 3JHH ) 7.8 Hz, 3JHH ) 7.2
Hz, 2H), 1.68-1.74 (m, 3H), 1.50-1.55 (m, 3H), 1.11 (s, 9H);
3
1.99-2.11 (m, 2H), 1.30 (s, 9H); 13C{1H} NMR δ 164.9 (d, JPC
2
1
) 9.2 Hz), 153.6 (d, JPC ) 16.2 Hz), 136.3 (d, JPC ) 31.6 Hz),
2
2
133.2 (d, JPC ) 13.2 Hz), 132.6 (d, JPC ) 12.6 Hz), 132.3 (d,
4JPC ) 2.7 Hz), 132.0 (d, JPC ) 2.7 Hz), 129.9 (d, JPC ) 10.5
4
3
13C{1H} NMR δ 153.8 (d, JPC ) 7.2 Hz), 153.6 (d, JPC ) 9.4
2
3
3
1
1
2
Hz), 129.8 (d, JPC ) 10.0 Hz), 128.4 (d, JPC ) 47.8 Hz, 2C),
Hz), 136.3 (d, JPC ) 45.9 Hz), 135.1 (d, JPC ) 10.5 Hz), 131.1
3
2
122.7 (d, JPC ) 5.6 Hz), 81.9 (d, JPC ) 27.9 Hz), 68.3, 56.1 (d,
4
1
3
(d, JPC ) 3.0 Hz), 129.4 (d, JPC ) 56.0 Hz), 128.2 (d, JPC
)
2JPC ) 3.2 Hz), 38.6 (d, JPC ) 11.4 Hz), 35.8 (bs), 30.0, 22.3 (d,
3
3
2
11.2 Hz), 58.3, 49.3 (d, JPC ) 3.4 Hz), 40.6 (d, JPC ) 5.7 Hz),
3JPC ) 5.4 Hz); 31P{1H} NMR δ 11.0, -143.2 (sept, 1JPF ) 713.4
35.0 (d, 2JPC ) 12.0 Hz), 30.0, 27.4 (d, 4JPC ) 3.4 Hz), 24.0, 22.8
Hz); 19F{1H} NMR δ -73.2 (d, JPF ) 713.4 Hz); trans isomer:
1
(d, JPC ) 8.6 Hz); 31P{1H} NMR δ 16.2.
3
1H NMR δ 7.88 (d, JPH ) 3.6 Hz, 1H), 7.48-7.56 (m, 6H),
4
(3IP)PdCl2(HN(Me)nBu) (6d). 1H NMR δ 8.74 (s, 1H),
7.76-7.79 (m, 4H), 7.43-7.46 (m, 2H), 7.37-7.40 (m, 4H),
3.27-3.32 (m, 1H), 3.13-3.20 (m, 1H), 2.89-2.92 (m, 2H), 2.64
7.35-7.43 (m, 4H), 5.67-5.74 (m, 1H), 4.99-5.01 (m, 1H),
3.94-3.98 (m, 1H), 3.25-3.26 (m, 1H), 2.88-3.03 (m, 2H),
2.57-2.64 (m, 2H), 2.44-2.49 (m, 1H), 1.99-2.11 (m, 2H), 1.30
3
3
(dd, JHH ) 6.6 Hz, JPH ) 4.2 Hz, 3H), 2.52-2.56 (m, 2H),
3
2
(s, 9H); 13C{1H} NMR δ 159.8 (d, JPC ) 7.6 Hz), 155.3 (d, JPC
) 17.4 Hz), 134.5 (d, 1JPC ) 34.2 Hz), 133.3 (d, 2JPC ) 13.4 Hz),
132.4 (d, 2JPC ) 12.6 Hz), 132.3 (d, 4JPC ) 2.7 Hz), 131.8 (d, 4JPC
3
2.38-2.45 (m, 1H), 2.04-2.10 (m, 1H), 1.90 (pseudo pent, JHH
) 7.8 Hz, 3JHH ) 7.2 Hz, 2H), 1.79-1.86 (m, 1H), 1.44-1.50 (m,
1H), 1.37-1.42 (m, 1H), 1.08 (s, 9H), 0.97 (t, 3JHH ) 7.2 Hz, 3H);
3
3
) 2.7 Hz), 129.9 (d, JPC ) 11.1 Hz), 129.7 (d, JPC ) 11.6 Hz),
13C{1H} NMR δ 153.7 (d, JPC ) 6.9 Hz), 153.6 (d, JPC ) 9.2
2
3
1
3
128.8 (d, JPC ) 49.8 Hz, 2C), 120.7 (d, JPC ) 6.3 Hz), 84.0 (d,
1
2
Hz), 136.3 (d, JPC ) 45.9 Hz), 135.1 (d, JPC ) 10.5 Hz), 131.2
2JPC ) 30.0 Hz), 68.3, 56.0 (d, JPC ) 3.9 Hz), 38.2 (d, JPC
)
2
2
4
1
3
(d, JPC ) 2.7 Hz), 129.6 (d, JPC ) 56.0 Hz), 128.5 (d, JPC
)
11.7 Hz), 36.9 (bs), 30.0, 22.8 (d, JPC ) 6.0 Hz); 31P{1H} NMR
3
3
3
11.4 Hz), 58.3, 53.4 (d, JPC ) 2.8 Hz), 40.6 (d, JPC ) 6.0 Hz),
δ 17.5, -143.2 (sept, JPF ) 713.4 Hz); 19F{1H} NMR δ -73.2
1
39.1 (d, 3JPC ) 3.6 Hz), 36.0 (d, 2JPC ) 12.2 Hz), 31.7, 30.0, 22.8
1
(d, JPF ) 713.4 Hz); IR 3319 (w), 2962 (s), 2927 (s), 2847 (s),
(d, JPC ) 8.6 Hz), 20.5, 14.3; 31P{1H} NMR δ 16.0.
3
2731 (w), 2678 (w), 1619 (w), 1579 (w), 1437 (m), 1403 (m), 1374
(w), 1307 (w), 1259 (w), 1192 (w), 1152 (w), 1094 (w), 1076 (w),
1023 (w), 996 (w), 974 (w), 921 (w), 836 (s), 801 (w), 743 (w),
721 (w), 694 (w), 552 (s). Anal. Calcd for C25H31F6NP2Pd: C, 47.82;
H, 4.98; N, 2.23. Found: C, 48.29; H, 5.07; N, 2.33.
(3IP)PdCl2(HNnBu2) (6e). 1H NMR δ 8.43 (s, 1H), 7.80-7.84
(m, 4H), 7.42-7.46 (m, 2H), 7.37-7.40 (m, 4H), 3.26-3.31 (m,
1H), 3.10-3.17 (m, 2H), 2.86-2.89 (m, 2H), 2.55-2.58 (m, 2H),
3
2.46-2.53 (m, 2H), 2.14-2.22 (m, 2H), 1.90 (pseudo pent, JHH
) 7.8 Hz, 3JHH ) 7.2 Hz, 2H), 1.82-1.88 (m, 2H), 1.43-1.51 (m,
2H), 1.34-1.41 (m, 2H), 1.02 (s, 9H), 0.97 (t, 3JHH ) 7.2 Hz, 6H);
(3IP)PdCl2(HN(C2H6)2) (6a). To a stirring solution of 2 (0.438
g, 0.853 mmol) in dichloromethane (25 mL) was added diethy-
lamine (0.062 g, 0.85 mmol) in dichloromethane (10 mL), and the
mixture was allowed to stir at ambient temperature for 4 h. Solvent
was removed, and the solid was triturated with diethyl ether. The
red solid was recrystallized from diethyl ether at -25 °C (0.321 g,
64%); mp 124-126 °C; 1H NMR44 δ 8.50 (s, 1H), 7.80-7.81 (m,
4H), 7.42-7.45 (m, 2H), 7.37-7.40 (m, 4H), 3.15-3.17 (m, 2H),
13C{1H} NMR δ 153.5 (d, JPC ) 8.6 Hz), 153.4 (d, JPC ) 6.2
3
2
1
2
Hz), 136.4 (d, JPC ) 45.4 Hz), 135.0 (d, JPC ) 10.8 Hz), 131.1
4
1
3
(d, JPC ) 2.8 Hz), 129.8 (d, JPC ) 55.8 Hz), 128.4 (d, JPC
)
3
3
11.1 Hz), 58.2, 52.3 (d, JPC ) 3.0 Hz), 40.7 (d, JPC ) 6.9 Hz),
34.9 (d, 2JPC ) 12.2 Hz), 32.2, 29.8, 22.8 (d, 3JPC ) 8.6 Hz), 20.6,
14.3; 31P{1H} NMR δ 15.8.
(3IP)PdCl2(HN(CH2C6H5)2) (6f). 1H NMR δ 8.22 (s, 1H),
7.52-7.58 (m, 8H), 7.39-7.43 (m, 8H), 7.30-7.33 (m, 4H),
3
3
2.88-2.91 (m, 2H), 2.60 (q, JHH ) 6.6 Hz, 4H), 2.09 (pent, JHH
) 7.2 Hz, 2H), 1.54 (t, 3JHH ) 6.6 Hz, 6H), 1.03 (s, 9H); 13C{1H}
2
3
4.36-4.41 (m, 2H), 3.86-3.94 (m, 1H), 3.76-3.80 (m, 2H),
NMR δ 153.5 (d, JPC ) 4.9 Hz), 153.4 (d, JPC ) 8.6 Hz), 136.4
3
1
3
4
2.84-2.87 (m, 2H), 2.42-2.45 (m, 2H), 1.86 (pseudo t, JHH
)
(d, JPC ) 45.7 Hz), 135.0 (d, JPC ) 10.8 Hz), 131.1 (d, JPC
)
7.8 Hz, JHH ) 7.2 Hz, 2H), 0.98 (s, 9H); 13C{1H} NMR δ 153.8
3
1
2
2.9 Hz), 129.8 (d, JPC ) 56.4 Hz), 128.4 (d, JPC ) 11.2 Hz),
58.3, 46.9 (d, 3JPC ) 2.8 Hz), 40.8 (d, 3JPC ) 6.6 Hz), 35.0 (d, 2JPC
(d, 3JPC ) 8.1 Hz), 153.4 (d, 2JPC ) 5.2 Hz), 136.4, 135.7 (d, 1JPC
2
4
) 12.1 Hz), 29.8, 22.9 (d, JPC ) 8.6 Hz), 15.6; 31P{1H} NMR δ
3
) 46.2 Hz), 135.1 (d, JPC ) 11.0 Hz), 131.1 (d, JPC ) 2.7 Hz),
1
3
130.3, 129.7 (d, JPC ) 56.6 Hz), 129.1, 128.4, 128.3 (d, JPC
)
15.6; IR 3236 (w), 2957 (s), 2920 (s), 2847 (s), 2728 (w), 2673
(w), 1617 (w), 1576 (w), 1457 (m), 1374 (m), 1306 (w), 1260 (w),
1181 (w), 1150 (w), 1090 (w), 1068 (w), 1022 (w), 948 (w), 893
(w), 825 (w), 802 (w), 742 (w), 719 (w), 692 (w). Anal. Calcd for
C26H37Cl2N2PPd: C, 53.30; H, 6.37; N, 4.78. Found: C, 53.52; H,
6.48; N, 4.56.
General Procedure for NMR Scale Imine Displacement
Reactions. In a drybox, a solution of amine (0.039 mmol) in 0.6
mL of CDCl3 was added to a vial containing 2 (0.020 g, 0.039
3
3
11.2 Hz), 58.1, 54.7 (d, JPC ) 2.7 Hz), 40.4 (d, JPC ) 7.8 Hz),
35.0 (d, JPC ) 12.2 Hz), 29.8, 22.7 (d, JPC ) 8.7 Hz); 31P{1H}
2
3
NMR δ 17.2.
(3IP)PdCl2(HN(C4H8)) (6g). 1H NMR δ 9.08 (s, 1H), 7.72-7.76
(m, 4H), 7.42-7.45 (m, 2H), 7.36-7.38 (m, 4H), 3.34-3.37 (m,
1H), 3.14-3.17 (m, 4H), 2.90-2.93 (m, 2H), 2.49-2.52 (m, 2H),
1.89 (pseudo pent, 3JHH ) 7.8 Hz, 3JHH ) 7.2 Hz, 2H), 1.83-1.88
(m, 2H), 1.62-1.64 (m, 2H), 1.14 (s, 9H); 13C{1H} NMR δ 153.9
(d, 3JPC ) 7.0 Hz), 153.7 (d, 2JPC ) 9.6 Hz), 136.3 (d, 1JPC ) 46.0
Hz), 135.2 (d, 2JPC ) 10.5 Hz), 131.2 (d, 4JPC ) 2.8 Hz), 129.3 (d,
(44) The 1H NMR signal for the N-H proton was not observed.

(3-Iminophosphine)palladium(II) Complexes
Organometallics, Vol. 28, No. 8, 2009 2501
3
3
1JPC ) 56.2 Hz), 128.2 (d, JPC ) 11.2 Hz), 58.4, 49.1 (d, JPC
)
and precipitated with pentane at -25 °C (0.621 g, 62.1%); mp
156-158 °C; 1H NMR δ 10.36 (d, 4JPH ) 16.8 Hz, 1H), 7.64-7.69
(m, 6H), 7.56-7.59 (m, 4H), 3.19-3.22 (m, 2H), 2.63-2.66 (m,
2H), 2.13 (pent, 3JHH ) 7.8 Hz, 2H), 1.61 (s, 9H); 13C{1H} NMR45
3
2
2.2 Hz), 40.5 (d, JPC ) 5.2 Hz), 35.0 (d, JPC ) 12.0 Hz), 30.1,
24.6 (d, JPC ) 4.2 Hz), 22.8 (d, JPC ) 8.2 Hz); 31P{1H} NMR δ
4
3
15.7.
1
3
(3IP)PdCl2(HNiPr2) (6h). H NMR δ 8.36 (s, 1H), 7.77-7.81
1
δ 163.4 (d, JPC ) 81.8 Hz), 161.6 (d, JPC ) 2.0 Hz), 150.0 (d,
4
3
2JPC ) 5.0 Hz), 133.7 (d, JPC ) 2.8 Hz), 132.0 (d, JPC ) 10.5
(m, 4H), 7.41-7.43 (m, 2H), 7.35-7.38 (m, 4H), 3.28-3.34 (m,
2H), 3.23-3.27 (m, 1H), 2.84-2.88 (m, 2H), 2.57-2.60 (m, 2H),
2
1
Hz), 129.6 (d, JPC ) 12.6 Hz), 129.6 (d, JPC ) 107.4 Hz), 63.0,
3
2
3
3
39.8 (d, JPC ) 9.6 Hz), 34.0 (d, JPC ) 10.6 Hz), 28.2, 23.5 (d,
3JPC ) 8.8 Hz); 31P{1H} NMR δ 27.5; 19F{1H} NMR δ -78.7; IR
3152 (w), 2960 (s), 2923 (s), 2850 (s), 2731 (w), 1651 (w), 1586
(w), 1458 (m), 1375 (m), 1288 (m), 1261 (m), 1224 (w), 1188 (w),
1151 (w), 1114 (w), 1096 (w), 1064 (w), 1032 (m), 958 (w), 798
(w), 752 (w), 720 (w), 697 (w), 633 (m). Anal. Calcd for
C44H52Cl2N2P2Pd2:46 C, 55.35; H, 5.50; N, 2.93. Found: C, 55.31;
H, 5.20; N, 2.82.
1.88 (pseudo pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.58 (d,
3JHH ) 6.0 Hz, 6H), 1.40 (d, JHH ) 6.6 Hz, 6H), 0.99 (s, 9H);
3
2
3
13C{1H} NMR δ 153.4 (d, JPC ) 8.4 Hz), 153.1 (d, JPC ) 5.8
1
2
Hz), 136.6 (d, JPC ) 46.0 Hz), 135.0 (d, JPC ) 10.6 Hz), 131.0
4
1
3
(d, JPC ) 2.7 Hz), 130.0 (d, JPC ) 56.1 Hz), 128.3 (d, JPC
)
3
3
11.2 Hz), 58.1, 49.2 (d, JPC ) 2.7 Hz), 41.0 (d, JPC ) 5.2 Hz),
2
4
34.9 (d, JPC ) 12.2 Hz), 29.7, 23.6 (bs), 23.4 (d, JPC ) 2.7 Hz),
22.8 (d, JPC ) 8.8 Hz); 31P{1H} NMR δ 15.4.
3
1
[(3IP)Pd(Br)]2[OTf]2 (8). To a stirring slurry of silver triflate
(0.192 g, 0.745 mmol) in dichloromethane (20 mL) was added 3
(0.448 g, 0.745 mmol) in dichloromethane (20 mL), and the mixture
was stirred at ambient temperature for 14 h in the absence of light.
Solvent was removed, and the orange solid was dissolved in THF
and precipitated with pentane at -25 °C (0.273 g, 54.6%); mp
159-160 °C; 1H NMR δ 10.35 (d, 4JPH ) 17.4 Hz, 1H), 7.64-7.68
(m, 6H), 7.56-7.59 (m, 4H), 3.18-3.21 (m, 2H), 2.64-2.67 (m,
(3IP)PdCl2(H2NCy) (6i). H NMR δ 8.78 (s, 1H), 7.76-7.80
(m, 4H), 7.43-7.46 (m, 2H), 7.37-7.40 (m, 4H), 3.06-3.11 (m,
3
3
1H), 2.89-2.92 (m, 2H), 2.66 (pseudo t, JHH ) 6.6 Hz, JPH
)
6.0 Hz, 2H), 2.53-2.56 (m, 2H), 2.26-2.28 (m, 2H), 1.90 (pseudo
3
3
pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.74-1.78 (m, 2H),
1.60-1.63 (m, 1H), 1.29-1.34 (m, 2H), 1.21-1.27 (m, 2H),
1.10-1.15 (m, 1H), 1.08 (s, 9H); 13C{1H} NMR δ 153.9 (d, JPC
2
3
1
) 6.8 Hz), 153.5 (d, JPC ) 9.2 Hz), 136.0 (d, JPC ) 46.2 Hz),
3
3
2H), 2.12 (pseudo pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.61
135.1 (d, 2JPC ) 10.6 Hz), 131.2 (d, 4JPC ) 2.8 Hz), 129.4 (d, 1JPC
(s, 9H); 13C{1H} NMR45 δ 163.5 (d, 1JPC ) 56.1 Hz), 161.6, 150.1
(d, JPC ) 15.4 Hz), 133.7 (d, JPC ) 2.7 Hz), 133.0 (d, JPC
3
3
) 56.6 Hz), 128.4 (d, JPC ) 11.4 Hz), 58.3, 52.8 (d, JPC ) 2.2
Hz), 40.6 (d, 3JPC ) 6.2 Hz), 36.1 (d, 4JPC ) 2.4 Hz), 35.0 (d, 2JPC
2
4
3
)
2
1
10.5 Hz), 129.6 (d, JPC ) 12.4 Hz), 129.4 (d, JPC ) 60.3 Hz),
63.0, 39.8 (d, 3JPC ) 9.8 Hz), 34.0 (d, 2JPC ) 11.0 Hz), 28.2, 23.5
(d, 3JPC ) 8.7 Hz); 31P{1H} NMR δ 27.9; 19F{1H} NMR δ -78.7;
IR 3155 (w), 3120 (w), 3041 (w), 2916 (s), 2854 (s), 2729 (w),
1649 (m), 1586 (w), 1457 (m), 1436 (m), 1400 (w), 1379 (m), 1332
(w), 1285 (m), 1259 (m), 1223 (m), 1192 (m), 1156 (m), 1114
(m), 1099 (w), 1062 (w), 1031 (m), 995 (w), 953 (w), 901 (w),
824 (w), 792 (w), 751 (m), 720 (m), 694 (m), 632 (m). Anal. Calcd
for C44H52Br2N2P2Pd2:46 C, 50.65; H, 5.02; N, 2.68. Found: C,
50.78; H, 5.12; N, 2.55.
) 12.3 Hz), 29.9, 25.5, 25.2, 22.7 (d, JPC ) 8.4 Hz); 31P{1H}
3
NMR δ 15.5.
(3IP)PdCl2(H2NtBu) (6j). H NMR δ 8.67 (s, 1H), 7.78-7.82
1
(m, 4H), 7.43-7.44 (m, 2H), 7.37-7.40 (m, 4H), 2.87-2.90 (m,
2H), 2.86 (d, 3JPH ) 6.0 Hz, 2H), 2.55-2.58 (m, 2H), 1.89 (pseudo
3
3
pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.45 (s, 9H), 1.05 (s,
9H); 13C{1H} NMR δ 153.8 (d, JPC ) 6.6 Hz), 153.5 (d, JPC
)
2
3
1
2
8.8 Hz), 136.0 (d, JPC ) 47.1 Hz), 135.1 (d, JPC ) 10.5 Hz),
131.2 (d, 4JPC ) 2.8 Hz), 129.5 (d, 1JPC ) 57.0 Hz), 128.4 (d, 3JPC
) 11.2 Hz), 58.3, 53.7 (d, 3JPC ) 1.4 Hz), 40.7 (d, 3JPC ) 6.4 Hz),
(3IP)Pd(OTf)2 (9). Method A: To a stirring slurry of silver
triflate (0.365 g, 1.42 mmol) in dichloromethane (20 mL) was added
2 (0.346 g, 0.676 mmol) in dichloromethane (20 mL), and the
mixture was stirred at ambient temperature for 14 h in the absence
of light. Solvent was removed, and the orange solid was dissolved
in THF and precipitated with pentane at -25 °C (0.287 g, 57.4%).
Method B: To a stirring slurry of silver triflate (0.038 g, 0.15 mmol)
in dichloromethane (10 mL) was added 7 (0.085 g, 0.14 mmol) in
dichloromethane (10 mL), and the mixture was stirred at ambient
temperature for 14 h in the absence of light. Solvent was removed,
and the orange solid was dissolved in THF and precipitated with
2
4
35.0 (d, JPC ) 12.2 Hz), 32.5 (d, JPC ) 2.2 Hz), 29.9, 22.8 (d,
3JPC ) 8.6 Hz); 31P{1H} NMR δ 15.8.
(3IP)PdCl2(H2N-p-CH3C6H4) (6k). Reaction time was 120 h at
ambient temperature, 24 h at 50 °C, then 24 h at 100 °C (51%
conversion based on 1H NMR); 1H NMR δ 8.68 (s, 1H), 7.79-7.82
(m, 4H), 7.43-7.44 (m, 2H), 7.37-7.40 (m, 4H), 7.21 (d, 3JHH
)
3
7.8 Hz, 2H), 7.01 (d, JHH ) 7.8 Hz, 2H), 2.94-2.96 (m, 2H),
2.88-2.90 (m, 2H), 2.55-2.58 (m, 2H), 2.31 (s, 3H), 1.89 (pseudo
pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.06 (s, 9H); 13C{1H}
3
3
NMR δ 153.6 (d, 2JPC ) 8.6 Hz), 153.5 (d, 3JPC ) 5.8 Hz), 143.9,
2
1
135.1 (d, JPC ) 10.5 Hz), 135.0 (d, JPC ) 47.2 Hz), 131.2 (d,
4JPC ) 2.8 Hz), 129.2, 129.1, 128.6 (d, 3JPC ) 11.4 Hz), 125.3 (d,
1JPC ) 57.4 Hz), 123.1, 58.3, 40.7 (d, 3JPC ) 6.4 Hz), 36.6 (d, 2JPC
1
pentane at -25 °C (0.073 g, 73%); mp 160-161 °C; H NMR δ
7.68-7.70 (m, 6H), 7.56-7.59 (m, 4H), 7.23 (bs, 1H), 3.02-3.05
(m, 2H), 2.69-2.72 (m, 2H), 2.31 (pent, 3JHH ) 7.8 Hz, 2H), 1.45
) 11.6 Hz), 32.5, 29.9, 22.8 (d, JPC ) 8.6 Hz); 31P{1H} NMR δ
3
45
2
(s, 9H); 13C{1H} NMR δ 164.1 (d, JPC ) 14.4 Hz), 160.9 (d,
1JPC ) 62.4 Hz), 159.6 (d, JPC ) 9.4 Hz), 134.1 (bs), 133.6 (d,
3
17.3.
(3IP)PdCl2(H2NCH2C6H5) (6l). 1H NMR δ 8.87 (s, 1H),
7.76-7.80 (m, 4H), 7.45-7.48 (m, 2H), 7.38-7.41 (m, 4H),
7.36-7.38 (m, 2H), 7.33-7.35 (m, 3H), 4.10-4.13 (m, 2H),
2.95-2.98 (m, 2H), 2.91-2.94 (m, 2H), 2.54-2.56 (m, 2H), 1.91
3JPC ) 9.0 Hz), 130.1 (d, JPC ) 13.2 Hz), 121.4 (d, JPC ) 65.1
2
1
2
3
Hz), 53.7, 39.8 (d, JPC ) 10.5 Hz), 36.1 (bs), 31.0, 23.8 (d, JPC
) 9.2 Hz); 31P{1H} NMR δ 22.3; 19F{1H} NMR δ -77.8; IR 3051
(w), 2958 (s), 2916 (s), 2843 (s), 1618 (w), 1581 (w), 1457 (m),
1435 (m), 1389 (w), 1368 (m), 1301 (s), 1228 (s), 1207 (s), 1166
(s), 1099 (m), 1068 (w), 1021 (s), 964 (w), 891 (w), 751 (m), 694
(m), 632 (m). Anal. Calcd for C24H26F6NO6PPdS2: C, 38.96; H,
3.54; N, 1.89. Found: C, 38.93; H, 3.01; N, 1.81.
3
3
(pseudo pent, JHH ) 7.8 Hz, JHH ) 7.2 Hz, 2H), 1.10 (s, 9H);
3
2
13C{1H} NMR δ 154.2 (d, JPC ) 6.8 Hz), 153.6 (d, JPC ) 9.0
Hz), 139.1 (d, 4JPC ) 3.4 Hz), 135.7 (d, 1JPC ) 47.0 Hz), 135.1 (d,
2JPC ) 10.8 Hz), 131.3 (d, 4JPC ) 2.8 Hz), 129.4, 129.1 (d, 1JPC
)
57.2 Hz), 128.5, 128.45, 128.39 (d, 3JPC ) 11.4 Hz), 58.5, 48.1 (d,
3JPC ) 2.6 Hz), 40.4 (d, 3JPC ) 6.3 Hz), 35.1 (d, 2JPC ) 12.3 Hz),
(3IP)Pd(CH3)Cl (10). Method A: To a stirring solution of 2
(0.521 g, 1.02 mmol) in THF (40 mL) at 0 °C was added
methyllithium (0.37 mL, 1.1 mmol) via syringe. The reaction was
30.0, 22.8 (d, JPC ) 8.6 Hz); 31P{1H} NMR δ 16.4.
3
[(3IP)Pd(Cl)]2[OTf]2 (7). To a stirring slurry of silver triflate
(0.410 g, 1.60 mmol) in dichloromethane (20 mL) was added 2
(0.819 g, 1.60 mmol) in dichloromethane (20 mL), and the mixture
was stirred at ambient temperature for 14 h in the absence of light.
Solvent was removed, and the orange solid was dissolved in THF
(45) The 13C{1H} NMR signal for the carbon atom of the triflate anion
was unobserved.
(46) Compounds 7 and 8 undergo loss of the triflate anions and a two-
electron reduction, resulting in palladium(I), prior to analysis.

2502 Organometallics, Vol. 28, No. 8, 2009
Shaffer and Schmidt

(3-Iminophosphine)palladium(II) Complexes
Organometallics, Vol. 28, No. 8, 2009 2503
warmed to ambient temperature over 14 h. Solvent was removed,
and the yellow solid was washed with diethyl ether. The solid was
dissolved in dichloromethane and precipitated with diethyl ether
(0.241 g, 48.2%). Method B: To a stirring solution of 2 (0.521 g,
1.02 mmol) in dichloromethane (40 mL) was added tetramethyltin
(0.28 mL, 2.03 mmol) via syringe. The reaction was stirred at
ambient temperature for 40 h. Solvent was removed, and the yellow
solid was washed with pentane (3 × 30 mL) to remove any leftover
tetramethyltin. The solid was dissolved in dichloromethane and
precipitated with diethyl ether (0.363 g, 72.6%); mp 139-141 °C;
4 h in the absence of light. Solvent was removed, and the yellow
solid was dissolved in dichloromethane and precipitated with
1
pentane (0.343 g, 68.6%); mp 153-154 °C; H NMR δ 7.75 (d,
4JPH ) 2.4 Hz, 1H), 7.51-7.53 (m, 2H), 7.42-7.48 (m, 8H),
3
2.82-2.84 (m, 2H), 2.39-2.42 (m, 2H), 2.03 (pent, JHH ) 7.2
Hz, 2H), 1.37 (s, 9H), 0.70 (bs, 3H); 13C{1H} NMR45 δ 157.2 (d,
2
1
3JPC ) 5.7 Hz), 152.9 (d, JPC ) 14.1 Hz), 134.4 (d, JPC ) 6.3
Hz), 133.2 (d, 2JPC ) 12.0 Hz), 131.9 (d, 4JPC ) 2.6 Hz), 129.2 (d,
1
3
3JPC ) 11.7 Hz), 128.0 (d, JPC ) 57.8 Hz), 64.0, 38.0 (d, JPC
)
2
3
2.6 Hz), 37.7 (d, JPC ) 12.3 Hz), 30.3, 23.1 (d, JPC ) 6.2 Hz),
6.6; 31P{1H} NMR δ 30.0; 19F{1H} NMR δ -78.2; IR 3053 (w),
2956 (s), 2920 (s), 2849 (s), 2724 (w), 2687 (w), 2314 (w), 1680
(w), 1622 (w), 1584 (m), 1530 (w), 1463 (s), 1438 (s), 1375 (m),
1337 (w), 1300 (s), 1258 (m), 1233 (s), 1208 (s), 1170 (s), 1103
(m), 1070 (m), 1019 (s), 994 (m), 961 (m), 894 (w), 798 (m), 748
(m), 697 (m), 635 (s). Anal. Calcd for C24H29F3NO3PPdS · 0.3
CH2Cl2: C, 46.22; H, 4.73; N, 2.22. Found: C, 46.38; H, 4.30; N,
2.60.
4
1H NMR δ 7.70 (d, JPH ) 3.0 Hz, 1H), 7.47-7.50 (m, 2H),
7.39-7.44 (m, 8H), 2.75-2.79 (m, 2H), 2.40-2.44 (m, 2H), 2.01
3
3
(pent, JHH ) 7.8 Hz, 2H), 1.43 (s, 9H), 0.64 (d, JPH ) 3.0 Hz,
3H); 13C{1H} NMR δ 157.5 (d, JPC ) 6.0 Hz), 152.2 (d, JPC
)
3
2
1
2
15.2 Hz), 135.8 (d, JPC ) 38.8 Hz), 133.5 (d, JPC ) 12.0 Hz),
131.3 (d, 4JPC ) 2.6 Hz), 129.0 (d, 3JPC ) 11.0 Hz), 128.9 (d, 1JPC
3
2
) 51.0 Hz), 63.6, 38.1 (d, JPC ) 1.8 Hz), 37.3 (d, JPC ) 11.3
Hz), 31.3, 23.2 (d, 3JPC ) 6.0 Hz), 3.6 (d, 2JPC ) 0.4 Hz); 31P{1H}
NMR δ 28.2; IR 3051 (w), 2926 (s), 2852 (s), 2724 (w), 2678 (w),
1620 (w), 1574 (w), 1460 (m), 1437 (m), 1377 (m), 1308 (w), 1231
(w), 1198 (w), 1157 (w), 1098 (w), 1070 (w), 1024 (w), 1000 (w),
992 (w), 942 (w), 892 (w), 791 (w), 759 (w), 735 (w), 717 (w),
690 (m). Anal. Calcd for C23H29ClNPPd: C, 56.11; H, 5.94; N,
2.84. Found: C, 56.13; H, 5.62; N, 2.78.
Crystallography. Summaries of crystal data and collection
parameters for crystal structures of 5, 6a, 7, and 9-12 are provided
in Table 1. Detailed descriptions of data collection, as well as data
solution, are provided below. ORTEP diagrams were generated with
the ORTEP-3 software package.47 For each sample, a suitable
crystal was mounted on a pulled glass fiber using Paratone-N
hydrocarbon oil. The crystal was transferred to a Siemens SMART48
diffractometer with a CCD area detector, centered in the X-ray
beam, and cooled to 140 K using a nitrogen-flow low-temperature
apparatus that had been previously calibrated by a thermocouple
placed at the same position as the crystal. An arbitrary hemisphere
of data was collected using 0.3° ω scans, and the data were
integrated by the program SAINT.49 The final unit cell parameters
were determined by a least-squares refinement of the reflections
with I > 10σ(I). Data analysis using Siemens XPREP50 and the
successful solution and refinement of the structure determined the
space group. An empirical absorption correction was applied using
SADABS.51 Equivalent reflections were averaged, and the structures
were solved by direct methods using the SHELXTL software
package.52 Unless otherwise noted, all non-hydrogen atoms were
refined anisotropically, and hydrogen atoms were included as fixed
atoms but not refined.
(3IP)Pd(CH3)Br (11). Method A: To a stirring solution of 2
(0.478 g, 0.931 mmol) in THF (40 mL) at 0 °C was added slowly
via syringe methyllithium complexed with lithium bromide (0.68
mL, 1.0 mmol). The reaction was allowed to warm to ambient
temperature over the course of 1 h. Solvent was removed to afford
a red-orange powder. The powder was dissolved in dichloromethane
and precipitated with diethyl ether (0.278 g, 55.6%). Method B:
To a stirring solution of 3 (0.560 g, 0.931 mmol) in dichloromethane
(40 mL) was added tetramethyltin (0.26 mL, 2.0 mmol) via syringe.
The reaction was stirred at ambient temperature for 40 h. Solvent
was removed, and the yellow solid was washed with pentane (3 ×
30 mL) to remove any leftover tetramethyltin. The solid was
dissolved in dichloromethane and precipitated with diethyl ether
(0.314 g, 62.8%). Method C: Lithium bromide (0.011 g, 0.12
mmol) and 10 (0.020 g, 0.041 mmol) were added to vials in the
drybox, followed by the addition of CDCl3 (0.5 mL) to each vial.
The contents of the vials were mixed and placed into a NMR tube.
Quantitative formation of 11 was observed by 1H, 13C, and 31P NMR
spectroscopy; mp 155-157 °C; 1H NMR δ 7.66 (d, 4JPH ) 3.0 Hz,
1H), 7.48-7.50 (m, 2H), 7.39-7.45 (m, 8H), 2.76-2.78 (m, 2H),
5: X-ray quality crystals were grown from a layered solution of
THF and pentane at ambient temperature. The asymmetric unit
contains two independent [(3IP)Pd(allyl)]+ cations. One is fully
ordered as the trans isomer, while the second has an allyl group
with a disordered central carbon atom, giving a 1:1 cis/trans ratio.
Thus, the overall crystal structure contains a 3:1 trans:cis ratio of
3
2.41-2.43 (m, 2H), 2.01 (pent, JHH ) 7.8 Hz, 2H), 1.40 (s, 9H),
0.71 (d, 3JPH ) 3.0 Hz, 3H); 13C{1H} NMR δ 158.0 (d, 3JPC ) 6.3
-
isomers. Additionally, the 2 equiv of PF6 necessary for charge
2
1
Hz), 152.2 (d, JPC ) 14.6 Hz), 136.0 (d, JPC ) 38.7 Hz), 133.4
balance are present as one fully occupied PF6- (with one disordered
fluorine) and two P0.5F3 units located at special positions: 0, 0, z
and 1/2, 0, z. The final cycle of full-matrix least-squares refinement
was based on 13 318 observed reflections and 653 variable
parameters and converged yielding final residuals: R ) 0.0494, Rall
) 0.0844, and GOF ) 0.867.
2
4
3
(d, JPC ) 12.0 Hz), 131.3 (d, JPC ) 2.4 Hz), 129.0 (d, JPC
10.8 Hz), 128.9 (d, JPC ) 67.5 Hz), 63.6, 38.1 (bs), 37.3 (d, JPC
)
1
2
3
2
) 11.1 Hz), 31.3, 23.1 (d, JPC ) 6.0 Hz), 2.0 (d, JPC ) 0.4 Hz);
31P{1H} NMR δ 28.5; IR 3050 (w), 2960 (s), 2923 (s), 2850 (s),
2722 (w), 2676 (w), 2199 (w), 1957 (w), 1884 (w), 1811 (w), 1699
(w), 1582 (w), 1463 (m), 1436 (m), 1380 (m), 1371 (m), 1307 (w),
1257 (w), 1225 (w), 1197 (w), 1161 (m), 1097 (m), 1023 (w), 987
(w), 964 (w), 913 (m), 890 (w), 845 (w), 794 (w), 730 (m), 693
(m), 643 (m). Anal. Calcd for C23H29BrNPPd: C, 51.46; H, 5.45;
N, 2.61. Found: C, 51.70; H, 5.51; N, 2.29.
6a: X-ray quality crystals were grown from a saturated solution
of diethyl ether at -25 °C. The final cycle of full-matrix least-
squares refinement was based on 6902 observed reflections and 293
variable parameters and converged, yielding final residuals: R )
0.0296, Rall ) 0.0436, and GOF ) 0.995.
(3IP)Pd(CH3)OTf (12). Method A: To a stirring slurry of silver
triflate (0.233 g, 0.908 mmol) in dichloromethane (20 mL) was
added a solution of 10 (0.406 g, 0.825 mmol) in dichloromethane
(20 mL), and the mixture was stirred at ambient temperature for
4 h in the absence of light. Solvent was removed, and the yellow
solid was dissolved in dichloromethane and precipitated with
pentane (0.378 g, 75.6%). Method B: To a stirring slurry of silver
triflate (0.233 g, 0.908 mmol) in dichloromethane (20 mL) was
added a solution of 11 (0.443 g, 0.825 mmol) in dichloromethane
(20 mL), and the mixture was stirred at ambient temperature for
(47) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
(48) SMART: Area-Detector Software Package, v5.625; Bruker AXS,
Inc.: Madison, WI, 1997-2001.
(49) SAINT: SAX Area-Detector Integration Program, V6.22; Bruker
AXS, Inc.: Madison, WI, 1997-2001.
(50) XPREP: Reciprocal Space Exploration Program, V6.12; Bruker
AXS, Inc.: Madison, WI, 2001.
(51) SADABS: Bruker/Siemens Area Detector Absorption Program,
V2.03; Bruker AXS, Inc.: Madison, WI, 2001.
(52) SHELXL-97: Structure Solution Program, V6.10; Bruker AXS, Inc.:
Madison, WI, 2000.

2504 Organometallics, Vol. 28, No. 8, 2009
Shaffer and Schmidt
7: X-ray quality crystals were grown from a layered solution of
THF and pentane at ambient temperature. The asymmetric unit
contained 1 equiv of CH2Cl2 in addition to dimeric 7. One tBu group
was disordered over two rotational positions. The final cycle of
full-matrix least-squares refinement was based on 13 270 observed
reflections and 623 variable parameters and converged, yielding
final residuals: R ) 0.0576, Rall ) 0.0594, and GOF ) 1.152.
11b: X-ray quality crystals were grown from a layered solution
of THF and pentane at ambient temperature. The final cycle of
full-matrix least-squares refinement was based on 5504 observed
reflections and 244 variable parameters and converged, yielding
final residuals: R ) 0.0367, Rall ) 0.0464, and GOF ) 0.960.
12: X-ray quality crystals were grown from a layered solution
of dichloromethane and diethyl ether at ambient temperature. The
final cycle of full-matrix least-squares refinement was based on 6343
observed reflections and 307 variable parameters and converged,
yielding final residuals: R ) 0.0319, Rall ) 0.0335, and GOF )
1.091.
9: X-ray quality crystals were grown from a layered solution of
THF and pentane at ambient temperature. The final cycle of full-
matrix least-squares refinement was based on 6933 observed
reflections and 370 variable parameters and converged, yielding
final residuals: R ) 0.0322, Rall ) 0.0394, and GOF 1.021.
Acknowledgment. This material is based upon work
supported by the National Science Foundation under CHE-
0841611. Additionally, we gratefully acknowledge the
University of Toledo for generous startup funding, as well
as a University of Toledo Interdisciplinary Research Initiation
Award.
10: X-ray quality crystals were grown from a saturated solution
of diethyl ether at ambient temperature. The final cycle of full-
matrix least-squares refinement was based on 5629 observed
reflections and 244 variable parameters and converged, yielding
final residuals: R ) 0.0306, Rall ) 0.0328, and GOF ) 1.108.
11a: X-ray quality crystals were grown from a layered solution
of dichloromethane and diethyl ether at ambient temperature. The
final cycle of full-matrix least-squares refinement was based on 5838
observed reflections and 244 variable parameters and converged,
yielding final residuals: R ) 0.0516, Rall ) 0.0677, and GOF )
1.067.
Supporting Information Available: CIF files providing ad-
ditional crystallographic data, including bond lengths and angles,
for compounds 5, 6a, 7, and 9-12. This material is available free
of charge via the Internet at http://pubs.acs.org.
OM900066T