A cyclodiphosphazane based pincer ligand, [2,6-{μ-(tBuN)2P(tBuHN)PO}2C6H3I]: NiII, PdII, PtII and CuI complexes and catalytic studies

Article abstract of DOI:10.1039/c4dt02810d

Synthesis and late-transition metal complexes of pincer capable cyclodiphosphazane, 2,6-{μ-(^tBuN)₂P(^tBuHN)PO}₂C₆H₃I (1) are described. The condensation of 2-iodoresorcinol with cis-{ClP(μ-N^tBu)₂PN(H)^tBu} produced a difunctional derivative 1 in good yield. The treatment of Ni(COD)₂, Pd₂(dba)₃·CHCl₃ or Pt(PPh₃)₄ with 1 afforded pincer complexes [2,6-{μ-(^tBuN)₂P(^tBuHN)PO}₂C₆H₃MI] (2 M = Ni; 3 M = Pd and 4 M = Pt). The reaction of complex 3 with copper halides resulted in the formation of heterobimetallic complexes bridged by rhombic {Cu(μ-X)}₂ units, [{{Cu(μ-X)}₂}{μ-(^tBuN)₂P(^tBuHN)PO}₂C₆H₃PdI] (5 X = I and 6 X = Br). The crystal structures of 1-3, 5 and 6 were established by single X-ray diffraction studies. The palladium complex 3 was tested for catalytic P-arylation of diphenylphosphine oxide (Ph₂P(O)H) under microwave irradiation. Moderate to good catalytic activity was observed with aryl bromides. This journal is

Full text of DOI:10.1039/c4dt02810d

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Cyclodiphosphazane based pincer ligand, [2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3I]: NiII,
PdII, PtII and CuI complexes and catalytic studies
Guddekoppa S. Ananthnaga, Joel T. Magueb and Maravanji S. Balakrishna∗,a
aPhosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay,
Powai, Mumbai 400 076, India.
bDepartment of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA.
Abstract. Synthesis and lateꢀtransition metal complexes of pincer capable
cyclodiphosphazane, 2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3I (1) is described. The condensation
of 2ꢀiodoresorcinol with cisꢀ{ClP(µꢀNtBu)2PN(H)tBu} produced a difunctional derivative 1
in good yield. The treatment of Ni(COD)2, Pd2(dba)3·CHCl3 or Pt(PPh3)4 with 1 afforded
pincer complexes [2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3MI] (2 M = Ni; 3 M = Pd and 4 M =
Pt). The reaction of complex 3 with copper halides resulted in the formation of
heterobimetallic complexes bridged by rhombic {Cu(µꢀX)}2 units, [{{Cu(µꢀX)}2{µꢀ
(tBuN)P(tBuHN)PO}2C6H3PdI] (5 X = I and 6 X = Br). The crystal structures of 1 − 3, 5 and
6 were established by single Xꢀray diffraction studies. The palladium complex 3 was tested
for catalytic Pꢀarylation of diphenylphosphine oxide (Ph2P(O)H) under microwave
irradiation. Moderate to good catalytic activity was observed with aryl bromides.
∗ Author to whom correspondence should be addressed. Eꢀmail: krishna@chem.iitb.ac.in,
msb_krishna@iitb.ac.in (M. S. Balakrishna); Fax: +91ꢀ22ꢀ5172ꢀ3480/2576ꢀ7152.
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Introduction
The family of pincer ligands attracted much attention in recent years1 mainly because of
their applications in homogenous catalysis,2ꢀ5 sensors,6 and supramolecular chemistry.7ꢀ9 The
pincer skeleton generally consists of two mutually trans chelating neutral donor groups and a
central aromatic backbone. The neutral donors are typically phosphines (PR2),7, 8, 10 arsines,11
amines (NR2),8, 12ꢀ15 thioethers (SR),13, 16ꢀ20 selenoethers (SeR)21 and Nꢀheterocyclic carbenes
25, 26
(NHCs)22ꢀ24 or a pair of donor groups among these functionalities.18,
The pincer
complexes of phosphorus donor ligands have been studied extensively.27ꢀ35 The steric and
electronic properties of pincer ligands can be controlled by carefully modifying the
substituents on donor groups and aromatic backbone.34, 36 However, modification of stereoꢀ
chemical parameters often require tedious multistep synthesis. In this context, pincer
complexes bearing bis(phosphinite) POCOP backbone are of special interest due to their
relatively easy synthetic access.37
Functionalized pincer complexes with multiple coordination sites are used to construct
heterobimetallic complexes with monoꢀ or polynuclear pincer fragments. Incorporation of
second metal center to a pincer framework can enhance their catalytic activity by synergic
interactions. η6ꢀCoordination of the organometallic fragments such as [Ru(η5ꢀC5R5)]+, to the
central arene ring of pincer complex to afford heterobimetallic products have been reported
by Gebbink and coꢀworkers and others.38ꢀ42 Spectroscopic and electrochemical data have
shown that the electrophilic organometallic fragments act as powerful electronꢀwithdrawing
groups. van Koten and coworkers recently reported the synthesis of heterobimetallic and
43
trimetallic complexes using a ditopic pincer terpyridine hybrid ligand.
Peripherally
metallated porphyrin pincer hybrids are successfully utilized as catalysts in Michael addition
reaction,44 Heck reaction45 and allylation reactions.46 Although they provide robust platform
2

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for multiꢀpincer assemblies, the role of porphyrin backbone in catalytic cycle is not clearly
understood.
The oxidative addition of low valent metal precursors to prefunctionalized ligands has
been used as an alternate method when direct cyclometalation is unsuccessful.2, 3, 47 The
method becomes more important when acidꢀlabile, thermally unstable or sterically bulky
substituents are present in the pincer ligand, since direct cyclometalation by C–H activation
normally requires high temperature and longer reaction time and formally releases acid
(HX).9, 27
In our quest for new type of phosphorus based ligand systems for catalytic and biological
applications, we have synthesized several functionalized phosphorus based ligands including
various cyclodiphosphazane derivatives and studied their complexation behavior, catalytic
applications and antitumor properties.48, 49 Slight modifications of the phosphorus substituents
of cyclodiphosphazanes have brought significant changes in their coordination behavior
resulting in the formation of several mononuclear complexes to metalloꢀmacrocycles and
coordination polymers.50, 51 We, herein report the synthesis of pincer complexes based on
acyclic dimer of cyclodiphosphazane. The preliminary investigations on the catalytic activity
of palladium complex in Pꢀarylation of diphenylphosphine oxide (Ph2P(O)H) is also reported.
Results and discussion
Ligand synthesis and oxidative addition reactions. An iodoꢀsubstituted acyclic dimer of
cyclodiphosphazane, 2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3I (1) having a rigid aromatic scaffold
was synthesized by the reaction of cisꢀ{ClP(µꢀNtBu)2PN(H)tBu} with 2ꢀiodoresorcinol. The
compound 1 is a white crystalline solid moderately stable towards air and moisture. The
31P{1H} NMR spectrum of 1 exhibits two doublets centered at 112.7 and 144.1 ppm, for
2
aminoꢀP and aryloxoꢀP atoms, respectively, with a JPP coupling of 12 Hz. The reaction of
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2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3I (1) with Ni(COD)2, Pd2(dba)3·CHCl3 or Pt(PPh3)4 in
THF under refluxing conditions resulted in the formation of corresponding pincer complexes,
[2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3MI] (2 M = Ni; 3 M = Pd and 4 M = Pt) as shown in
Scheme 1. The 31P{1H} NMR spectra of 2, 3 and 4 follow similar pattern. For example, the
31P{1H} NMR spectrum of platinum complex 4 consists of two signals at 121.6 and 99.2 ppm
for coordinated and uncoordinated phosphorus centers, respectively, with former showing a
2
1JPtP coupling of 3925 Hz. No JPP coupling was observed in any of the metal complexes.52
From the 31P{1H} NMR spectral data it is clear that the aryloxoꢀP atoms are coordinating to
the metal centers. The EI mass spectra of complexes 2 and 3 showed [M+H] ion peaks at m/z
845.10 and 892.71, respectively. The structures of 1 – 3 have been confirmed by single
crystal Xꢀray diffraction studies.
Molecular structures of 2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3I (1), and [2,6-{µ-
(tBuN)P(tBuHN)PO}2C6H3MI] (2 M = Ni and 3 M = Pd). The perspective views of
molecular structures 1 – 3 along with the atom labeling schemes are shown in Figures 1 – 3.
The selected bond lengths [Å] and bond angles [°] are listed in Table 1, while the
crystallographic data and the details of the structure determination are given in Table 2.
The crystals suitable for single crystal Xꢀray diffraction study were obtained from toluene
solution of 1 at −20 °C. The average P–O bond distance [1.700 Å] in 1 is longer than the
4

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same in analogous compounds, 1,3ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H4 [1.6705(13) Å],53
{CH2OP(ꢀꢀNtBu)2PN(H)tBu}2 [1.6383(14) Å],54 Et2C(CH2OP(ꢀꢀNtBu)2PN(H)tBu)2 [1.629(2)
Å],55 and {tBu(H)NP(ꢀꢀNtBu)2POC6H4PPh2ꢀo} [1.6881(11) Å].52 The average endocyclic
P−N bond distance of phosphorus bearing an aryloxo substituent is 1.684 Å, whereas the
average P−N bond distance, where phosphorus is bound to exocyclic nitrogen is 1.743 Å.
Generally, the longer P−N bonds are associated with phosphorus atom having an exocyclic
nitrogen substituent, whereas phosphorus bearing oxoꢀ, alkoxoꢀ, aryloxoꢀ, or haloꢀ
substituents show shorter P−N bond distances.56, 57 The exocyclic P3−N5 [1.666(3) Å] and
P4−N6 [1.659(3) Å] bond distances are shorter than the average endocyclic P−N [1.715(3) Å]
bond distances. The P2N2 rings in 1 are slightly puckered with a folding along N···N axis, as
indicated by the dihedral angle between the corresponding N–P–N planes (P1N1P3N2 =
6.13° and P2N3P4N4 = 1.24°).
Figure 1. The molecular structure of 2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3I (1). All hydrogen
atoms are omitted for clarity. Thermal ellipsoids are drawn at 50% probability level.
Symmetry operation i = ꢀx, ꢀy, z+1/2.
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The crystal structures of 2 and 3 confirm the oxidative addition of C—I bond to metal
centre along with the coordination of two aryloxoꢀphosphorus atoms. The geometry around
the metal center in both the complexes 2 and 3 is distorted square planar. A slight distortion
primarily arises from the relatively small P–M–P angles in 2 [166.28(6)°] and 3 [162.20(4)°].
The average P–O bond distances in 2 [1.652 Å] and 3 [1.648 Å] are shorter than the same in
ligand 1 [1.700 Å]. The Ni1–P1 and Ni1–P2 bond distances are 2.1668(13) Å and 2.1621(11)
Å, respectively. The Ni–P bond distances are similar to those observed in [NiCl{2,6ꢀ
C6H3(OPPh2)2}] [2.157 Å] and [NiI{2,6ꢀC6H3(OPPh2)2}] [2.158 Å].58ꢀ60 The P1–O1 and P2–
O2 bond distances in 3 are essentially the same [1.648(3) Å] and are slightly shorter than
those of free ligand 1 [P1–O1 = 1.694(3) Å and P2–O2 = 1.708(3) Å]. The Pd1–C25
(1.980(3) Å) and Pd1–I1 (2.6608 Å) bond distances in 3 are similar to those reported for
analogous pincer complexes of the type [PdI{2,6ꢀC6H3(OPR2)2}] (Pd–C, 1.98 to 2.02 Å and
Pd–I, 2.40 to 2.66 Å).47 The Pd1–P1 and Pd1–P2 bond distances are 2.2758(9) Å and
2.2910(9) Å, respectively. The M–P bond distances in nickel complex 2 are slightly shorter
than the same in palladium complex 3 which is expected due to the larger atomic radius of
palladium. The C–M–I bonds are almost linear in both 2 (176.92°) and 3 (174.79(9)°). The
metallocycles and the benzene rings are coplanar; two P2N2 rings are pointed outwards from
metal centre in both the complexes.
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Figure 2. Molecular structure of [2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3NiI] (2). All hydrogen
atoms and lattice solvents are omitted for clarity. Thermal ellipsoids are drawn at 50%
probability level. Symmetry operation i = ꢀx+1/2, y+1/2, ꢀz+1/2.
Figure 4. The molecular structure of [2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3PdI] (3). All
hydrogen atoms and lattice solvents are omitted for clarity. Thermal ellipsoids are drawn at
50% probability level. Symmetry operation i = ꢀx, y+1/2, ꢀz+1/2.
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Synthesis of multi-metallic copper(I)-palladium(II) complexes. The multiꢀmetallic
complexes and were obtained by reacting the metalloꢀligand 2,6ꢀ{µꢀ
5
6
(tBuN)P(tBuHN)PO}2C6H3PdI (3) with two equiv of CuI or CuBr. The dimeric complexes
bridged by rhombic {Cu(µꢀX)}2 units were precipitated out from the reaction mixture as
insoluble off white solids. However, partial solubility of compound 5 in DMSO allowed
spectral characterization. The 31P{1H} NMR spectrum of 5 showed two resonances; a sharp
singlet at 122 ppm was assigned to palladium bound phosphorus centers, whereas the broad
resonance at 75.0 ppm was due to the phosphorus centers coordinated to copper atoms. The
molecular structures of 5 and 6 were established by single crystal Xꢀray analysis.
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Figure 5. The molecular structure of [{{Cu(µꢀI)}2}2,6ꢀ{µꢀ(tBuN)P(tBuHN)PO}2C6H3PdI]
(5). All hydrogen atoms are omitted for clarity. Thermal ellipsoids are drawn at 50%
probability level. Symmetry operation i = ꢀx+1/2, y+1/2, ꢀz+1/2.
Molecular structures of complexes 5 and 6. The Xꢀray quality crystals of complexes 5 and
6 were obtained by slow diffusion of copper halide solution in acetonitrile into a
dichloromethane solution of 3 at room temperature. The pincer units in 5 and 6 are bridged
by rhombic {Cu(µꢀX)}2 units to form pincer dimers. The rhombic {Cu(µꢀX)}2 units present
in 5 and 6 consists of both tricoordinated and tetracoordinated copper centers (Figures 5 and
6). The tricoordinated copper centers adopt trigonal planar geometry, whereas the
tetracoordinated copper centers assume distorted tetrahedral geometry. The Cu1–I1Pd bond
distance in 5 is 2.9302(12) Å. The average Cu–I bond distance [2.557 Å] for tricoordinated
copper centers is less than the same in the tetracoordinated centers [2.654 Å]. The increase in
the bond lengths are due to the increase in coordination number from three to four. Similar
trend is also observed in complex 6. The tricoordinated copper centers in 5 and 6 adopt planer
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geometry (Σ∠Cu = 359.9°). In 6, one of the copper atoms of {Cu(µꢀBr)}2 units is coordinated
by a water molecule. The water molecule shows weak interactions with palladium bound
iodine atom with a H—I distance of 2.239 Å and O—H—I bond angle of 171.8o. The average
Cu–P bond distance in 5 (2.209 Å) is marginally greater than the same in 6 (2.196 Å). The
Pd1–I1 [2.6724(9) Å] and Pd1–C [1.993(5) Å] bonds in 5 are slightly elongated compared to
that of 3 [Pd1–I1 (2.6608(4) Å and Pd1–C 1.980(3) Å] due to the interaction of palladium
bound iodine with copper center. Similar elongations of bond lengths are not observed in 6.
The fourꢀmembered {Cu2(µꢀX)2} and P2N2 rings are slightly puckered as indicated by their
torsion angles.
Figure
6.
The
molecular
structure
of
[{{Cu(µꢀBr)}2(OH2)}2,6ꢀ{µꢀ
(tBuN)P(tBuHN)PO}2C6H3PdI] (6). All hydrogen atoms and lattice solvents are omitted for
clarity. Thermal ellipsoids are drawn at 50% probability level. Symmetry operation i = ꢀ
x+1/2, y+1/2, ꢀz+1/2.
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Catalytic P-arylation reactions. The aryl phosphine oxides are of importance due to their
applications in polymer chemistry,61 and photoelectric materials.62 Also, many of them are
used as ligands or ligand precursors in organoꢀ and transition metal catalysis.63 Synthesis of
arylphosphine oxides generally involves Li or Mg reagents; however, they lack functional
groups tolerance. Metal catalyzed C–P bond forming reactions offer a versatile alternative
method.61, 64 Several Palladium,65, 66 nickel67 and copper68 based catalytic systems have been
employed for the preparation of aryl phosphonates and phosphine oxides by Pꢀarylation of Hꢀ
phosphine oxides. Recently, palladacycles were effectively utilized in C–P bond forming
reactions.65, 69 In order to evaluate the catalytic efficiency of palladium pincer complex 3, Pꢀ
arylation reactions were performed under microwave irradiation conditions.
3 (3 mol%), Cs2CO3
ArP(O)Ph2
Ph2P(O)H
ArBr
MeCN, MW, 10 min
100 °C
Scheme 2. Pꢀarylation reactions
Initially, the coupling of bromobenzene with diphenylphosphine oxide was performed to
test the catalytic ability of palladium complex 3 under microwave irradiation. An excellent
yield of triphenylphosphine oxide was obtained when Cs2CO3 was used as a base in
acetonitrile at 100 °C. The coupling reaction was strongly influenced by the base. Replacing
Cs2CO3 with K2CO3 or K3PO4 gave only moderate conversions. Several aryl halides were
tested for Pꢀarylation reaction and moderate to good yields of arylphosphine oxides are
obtained (Scheme 2). For example, bromobenzene or bromotoluenes underwent Pꢀarylation
reaction with good yield in acetonitrile (Chart 1, entries a – c). Both the electron donating and
electron withdrawing substituents showed good conversions (Chart 1, entries d – i). In
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contrast, the coupling reaction of 2ꢀbromopyridine or 4ꢀchloroacetophenone with
diphenylphosphine oxide was not successful and resulted in negligible conversions.
O
O
O
O
O
O
PPh2
CN
PPh2
PPh2
PPh2
PPh2
PPh2
OMe
OMe
f
b
d
a
e
c
91%
95%
92%
82%
94%
69%
O
O
O
PPh2
PPh2
PPh2
OH
O
O
i
g
h
89%
79%
43%
Substrate scope in Pꢀarylation reaction
Chart 1.
Conclusions
The present study has shown that the cyclodiphosphazane based ligand 1 can serve as an
attractive template for the synthesis of monoꢀ and multiꢀmetallic complexes. The oxidative
addition of lowꢀvalent metal precursors to 1 produced pincer complexes in good yield. The
uncoordinated phosphorus centers in palladium complex were utilized to make mixed copperꢀ
palladium complexes. Interestingly, in the complex 6, two of the copper centers are
coordinated by water molecules. The palladium bound iodine atoms show bonding
interactions with copper atoms which can be exploited in catalytic reactions as this
interaction can polarize the Pd–I bond. These features not seen in conventional pincer ligands
may come handy in tuning the catalytic activity of such complexes for various organic
transformations. The catalytic activity of palladium complex 3 was tested for Pꢀarylation
reaction of diphenylphosphine oxide. Good yields were observed with aryl bromide
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substrates. Current investigations are directed towards the study of cooperative effect of two
metal centers in CuꢀꢀPd heterometalic complexes for various catalytic transformations.
Experimental section
General procedures. All manipulations were performed using standard vacuum line and
Schlenk techniques under nitrogen atmosphere unless otherwise stated. All the solvents were
purified by conventional procedures and distilled prior to use.70 The compounds 2ꢀ
iodoresorcinol,71 cisꢀ{ClP(µꢀNtBu)2PN(H)tBu},72 Pd2(dba)3·CHCl3,73 Pt(PPh3)4 and CuBr75
74
were prepared according to the published procedures. CuI and Ni(COD)2 were purchased
from Aldrich chemicals and used as such without further purification. Other chemicals were
obtained from commercial sources and purified prior to use.
Instrumentation. The NMR spectra were recorded at the following frequencies: 400 MHz
(1H), 100 MHz (13C), 162 or 202 MHz (31P) using either Varian VXR 400, Bruker AV 400 or
AV 500 spectrometers. 13C and 31P NMR spectra were acquired using broad band decoupling.
The spectra were recorded in CDCl3 (or DMSOꢀd6) solutions with CDCl3 (or DMSOꢀd6) as
internal lock; chemical shifts of 1H and 13C NMR spectra are reported in ppm downfield from
31
TMS, used as internal standard. The chemical shifts of P NMR spectra are referred to 85%
H3PO4 (in D2O) as external standard. The signals are quoted as s (singlet), d (doublet), t
(triplet), m (multiplet) and br (broad). The microanalyses were performed using a Carlo Erba
Model 1112 elemental analyzer. The mass spectra were recorded using Waters QꢀTof micro
(YAꢀ105). The melting points were observed in capillary tubes and are uncorrected.
Synthesis of 2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3I (1). To a mixture of 2ꢀiodoresorcinol
(0.7 g, 2.97 mmol) and triethylamine (1.1 g, 1.5 mL, 11.6 mmol) in diethyl ether (25 mL) was
added dropwise a solution of cisꢀ{ClP(µꢀNtBu)2PN(H)tBu} (1.85 g, 5.94 mmol) in diethyl
ether (30 mL) at 0 °C. The reaction mixture was warmed to room temperature and stirred
overnight. Triethyl amine hydrochloride formed was filtered through a frit layered with
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activated Celite. The solvent was evaporated under reduced pressure to obtain 1 as white
solid. Analytically pure product of 1 was obtained by recrystalizing the crude product in
toluene. Yield: 73% (1.7 g). Mp: 126–130 °C. Anal. Calcd. for C30H59IN6O2P4: C, 45.81; H,
7.56; N, 10.68. Found: C, 45.48; H, 7.43; N, 10.74. 1H NMR (400 MHz, CDCl3): δ 7.12ꢀ7.05
2
t
(m, 3H, Ar), 3.41 (d, JPH = 8.0 Hz, 2H, NH), 1.37–1.30 (m, br, 54H, Bu). 13C{1H} NMR
(100 MHz, CDCl3): δ 156.3, 128.3, 112.5, 112.3, 51.7, 51.6, 32.8, 31.4. 31P{1H} NMR (162
MHz, CDCl3): δ 144.1 (d, 2JPP = 12 Hz), 112.7 (d). MS (EI): m/z 661.1 [M–I]+.
Synthesis of [2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3NiI] (2). A mixture of 1 (0.04 g, 0.051
mmol) and Ni(COD)2 (0.014 g, 0.051 mmol) in THF (20 mL) was refluxed for 6 h. The
reaction mixture was allowed cool to room temperature. The solution was filtered and the
solvent was removed under vacuum to obtain a yellow solid. The yellow solid was washed
twice with hot petroleum ether to obtain yellow crystalline material of 2. Analytically pure 2
was obtained by recrystallizing the crude product in a 1:1 mixture of dichloromethaneꢀ
petroleum ether. Yield: 72% (0.031 g). Mp: >254 °C (dec). Anal. Calcd. for
1
C30H59IN6O2P4Ni·CH2Cl2: C, 40.02; H, 6.61; N, 9.03. Found: C, 39.79; H, 7.32; N, 8.75. H
NMR (400 MHz, CDCl3): δ 7.07 (t, 3JHH = 7.6 Hz, Ar, 1H), 6.47 (d, 3JHH = 7.6 Hz, Ar, 2H),
3
t
t
13
3.29 (d, JPH = 6.8 Hz, NH, 2H), 1.46 (s, Bu, 36H), 1.36 (s, Bu, 18H). C{1H} NMR (100
31
MHz, CDCl3): δ 160.3, 135.5, 128.9, 105.1, 52.5, 32.2. P{1H} NMR (162 MHz, CDCl3): δ
133.6 (s), 101.7 (s). MS (EI): m/z 845.1 [M+H]+.
Synthesis of [2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3PdI] (3). This compound was prepared
analogously to 2 by refluxing a mixture of Pd2(dba)3·CHCl3 (0.078 g, 0.075 mmol) and 1
(0.12 g, 0.153 mmol) in THF (20 mL). Yield: 71% (0.11 g). Mp: 265–268 °C. Anal. Calcd.
for C30H59IN6O2P4Pd: C, 40.35; H, 6.66; N, 9.41. Found: C, 40.77; H, 6.60; N, 9.05. 1H NMR
(400 MHz, CDCl3): δ 7.10 (tt, 3JHH = 8.0 Hz, 5JPH = 1.6 Hz, 1H, Ar), 7.00 (d, 3JHH = 8.0 Hz,
2
t
4
t
2H, Ar), 3.31 (d, JPH = 7.2 Hz, 2H, NH), 1.42 (s, Bu, 36H), 1.36 (d, JPH = 1.3 Hz, Bu,
14

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18H). 13C{1H} NMR (100 MHz, CDCl3): δ 157.1, 129.1, 128.7, 106.0, 52.7, 33.0, 32.2.
31P{1H} NMR (162 MHz, CDCl3): δ 126.7 (s), 100.8 (s). MS (EI): m/z 892.7 [M]+.
Synthesis of [2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3PtI] (4). This compound was prepared
analogously to 2 by refluxing a mixture of Pt(PPh3)4 (0.064 g, 0.051 mmol) and 1 (0.04 g,
0.051 mmol) in THF (20 mL). Yield: 79% (0.039 g). Mp: >270 °C. Anal. Calcd. for
1
C30H59IN6O2P4Pt: C, 36.70; H, 6.06; N, 8.56. Found: C, 36.36; H, 5.89; N, 8.85. H NMR
3
t
(400 MHz, CDCl3): δ 7.30–7.08 (m, Ar, 3H), 3.29 (d, JPH = 7 Hz, NH, 2H), 1.36 (s, Bu,
t
36H), 1.30 (s, Bu, 18H). 13C{1H} NMR (100 MHz, CDCl3): δ 157.2, 133.6, 128.5, 105.4,
52.5, 32.8. 31P{1H} NMR (162 MHz, CDCl3): δ 121.6 (s, 1JPtP = 3925 Hz), 99.2 (s).
Synthesis of [{{Cu(µ-I)}2}2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3PdI] (5). An acetonitrile (5
mL) solution of CuI (0.0145 g, 0.0761 mmol) was added dropwise over a well stirred solution
of 3 (0.034 g, 0.0387 mmol) in dichloromethane (5 mL) and stirring was continued for
another 4 h at room temperature. The solvent was evaporated, and the residue was washed
with petroleum ether (5 mL) and dried under reduced pressure to form the analytically pure
product 5 as off white solid. Yield: 93% (0.045 g). Mp: >270°C. Anal. Calcd. for
1
C60H118I6N12O4P8Cu4Pd2: C, 28.28; H, 4.67; N, 6.60. Found: C, 28.20; H, 4.40; N, 6.85. H
3
3
NMR (400 MHz, DMSOꢀd6): δ 7.16 (t, JHH = 7.8 Hz, Ar, 2H), 6.65 (d, JHH = 7.8 Hz, Ar,
t
t
4H), 5.50 (br, s, NH, 4H), 1.41 (s, Bu, 72H), 1.40 (s, Bu, 36H). 31P{1H} NMR (162 MHz,
DMSOꢀd6): δ 122.0 (s), 75.0 (br, s).
Synthesis of [{{Cu(µ-Br)}2}2,6-{µ-(tBuN)P(tBuHN)PO}2C6H3PdI] (6). This compound
was prepared analogously to 5 by adding a solution of CuBr (0.0081 g, 0.0562 mmol) in
acetonitrile (5 mL) to the solution of 3 (0.0251 g, 0.0281 mmol) in dichloromethane (5 mL).
Yield: 90% (0.029 g). Mp: >270°C. Anal. Calcd. for C60H118N12O4P8I2Br4Cu4Pd2: C, 30.54;
H, 5.04; N, 7.12. Found: C, 30.55; H, 5.01; N, 7.31.
15

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DOI: 10.1039/C4DT02810D
General procedure for the catalytic P-arylation reactions. The reactions were
performed in a sealed tube containing a mixture of aryl halide (1.0 equiv), diphenylphosphine
oxide (1.0 equiv), Cs2CO3 (1.2 equiv), catalyst 3 (3 mol%) and acetonitrile (4 mL). An initial
microwave power of 150 W was applied to reach 100 °C temperature. After specified
reaction time, the reaction mixture was filtered through Celite and diluted with H2O (5 mL)
and Et2O (5 mL) followed by extraction with diethylether (2 × 5 mL). The combined organic
fractions were dried over Na2SO4 and the solvent was removed under reduced pressure. The
crude products were purified by silica gel column chromatography using ethyl acetate as the
eluent. Yields were calculated versus diphenylphosphine oxide.
X-Ray crystallography. Crystal of each of the compounds 1 – 3, 5 and 6 suitable for Xꢀray
crystal analysis were mounted on a Cryoloop with a drop of Paratone oil and placed in the
cold nitrogen stream of the Kryoflex attachment of the Bruker APEX CCD diffractometer. A
full sphere of data was collected using 606 scans in ω (0.3º per scan) at φ = 0, 120 and 240º
using the SMART76 software package, or the APEX277 program suite. The raw data were
reduced to F2 values using the SAINT+ software. Multiple measurements of equivalent
reflections provided the basis for an empirical absorption correction as well as a correction
for any crystal deterioration during the data collection (SADABS78). The structures 2 and 5
were solved by heavy atom method, while remaining structures were solved by direct method
and refined by fullꢀmatrix leastꢀsquares procedures using the SHELXTL program package.78
Multiple measurements of equivalent reflections provided the basis for empirical absorption
corrections as well as corrections for any crystal deterioration during the data collection
(SADABS). Hydrogen atoms attached to carbon were placed in calculated positions and
included as riding contributions with isotropic displacement parameters tied to those of the
attached nonꢀhydrogen atoms. Those attached to nitrogen were placed in locations derived
from a difference map and also included as riding contributions as for the others. The
16

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isotropic thermal parameters of the hydrogen atoms were fixed at 1.2 times that of the
corresponding carbon for phenyl hydrogen and 1.5 times for C(CH3)3. In the final refinement,
the hydrogen atoms were riding with the carbon atom to which they were bonded. The details
of Xꢀray structural determinations are given in Table 2. Crystallographic data for the
structures reported in this paper have been deposited with the Cambridge Crystallographic
Data Centre as supplementary publication no. CCDC 1023326 (compound 1), 1023322
(compound 2), 1023323 (compound 3), 1023324 (compound 5) and 1023325 (compound 6).
Acknowledgment
The work is supported by a grant No.SB/S1/ICꢀ08/2014 from Science & Engineering
Research Board, New Delhi, India. GSA thanks CSIR, New Delhi for Research Fellowship
(SRF). We also thank the Department of Chemistry Instrumentation Facilities, IIT Bombay,
for spectral and analytical data. JTM thanks the Louisiana Board of Regents for the purchase
of the CCD diffractometer and the Chemistry Department of Tulane University for support of
the Xꢀray laboratory.
Supporting Information
Xꢀray crystallographic files in CIF format for the structure determinations of 1 – 3, 5 and
6 and copies of 31P{1H} NMR spectra of the compounds.
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DOI: 10.1039/C4DT02810D
References
1.
D. MoralesꢀMorales and C. M. Jensen (Eds.), The Chemistry of Pincer Compounds,
Elsevier, Amsterdam, The Netherlands, 2007.
2.
3.
N. Selander and K. J. Szabo, Chem. Rev., 2011, 111, 2048ꢀ2076.
J. Aydin, K. S. Kumar, M. J. Sayah, O. A. Wallner and K. J. Szabo, J. Org. Chem.,
2007, 72, 4689ꢀ4697.
4.
R. Ahuja, B. Punji, M. Findlater, C. Supplee, W. Schinski, M. Brookhart and A. S.
Goldman, Nat. Chem., 2011, 3, 167ꢀ171.
5.
6.
G. van Koten, J. Organomet. Chem., 2013, 730, 156ꢀ164.
N. Ashkenazi, A. Vigalok, S. Parthiban, Y. BenꢀDavid, L. J. W. Shimon, J. M. L.
Martin and D. Milstein, J. Am. Chem. Soc., 2000, 122, 8797ꢀ8798.
M. E. van der Boom and D. Milstein, Chem. Rev., 2003, 103, 1759ꢀ1792.
M. Albrecht and G. van Koten, Angew. Chem. Int. Ed., 2001, 40, 3750ꢀ3781.
D. BenitoꢀGaragorri and K. Kirchner, Acc. Chem. Res., 2008, 41, 201ꢀ213.
F. EstudianteꢀNegrete, S. HernándezꢀOrtega and D. MoralesꢀMorales, Inorg. Chim.
Acta, 2012, 387, 58ꢀ63.
7.
8.
9.
10.
11.
12.
13.
14.
15.
D. F. Brayton, P. R. Beaumont, E. Y. Fukushima, H. T. Sartain, D. MoralesꢀMorales
and C. M. Jensen, Organometallics, 2014, 33, 5198ꢀ5202.
A. Boudier, P.ꢀA. R. Breuil, L. Magna, H. OlivierꢀBourbigou and P. Braunstein,
Chem. Commun., 2014, 50, 1398ꢀ1407.
C. CrisóstomoꢀLucas, R. A. Toscano and D. MoralesꢀMorales, Tetrahedron Lett.,
2013, 54, 3116ꢀ3119.
O. BaldovinoꢀPantaleo´n, S. Herna´ndezꢀOrtega and D. MoralesꢀMorales, Adv. Synth.
Catal., 2006, 348, 236ꢀ242.
O. BaldovinoꢀPantaleo´n, S. Herna´ndezꢀOrtega and D. MoralesꢀMorales, Inorg.
Chem. Commun., 2005, 8, 955–959.
16.
17.
R. A. Begum, D. Powell and K. BowmanꢀJames, Inorg. Chem., 2006, 45, 964ꢀ966.
R. Cervantes, S. Castillejos, S. J. Loeb, L. OrtizꢀFrade, J. Tiburcio and H. Torrens,
Eur. J. Inorg. Chem., 2006, 2006, 1076ꢀ1083.
18.
19.
M. BasauriꢀMolina, S. HernándezꢀOrtega and D. MoralesꢀMorales, Eur. J. Inorg.
Chem., 2014, 4619ꢀ4625.
E. PazꢀMorales, S. Herna´ndezꢀOrtega and D. MoralesꢀMorales, Acta
Crystallographica Section E, 2013, E69, m139–m140.
18

Page 19 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C4DT02810D
20.
V. Go´mezꢀBenı´tez, S. n. Herna´ndezꢀOrtega, R. n. A. Toscano and D. Moralesꢀ
Morales, Inorg. Chim. Acta, 2007, 360, 2128ꢀ2138.
21.
22.
D. Das, P. Singh, M. Singh and A. K. Singh, Dalton Trans., 2010, 39, 10876ꢀ10882.
M. Raynal, C. S. J. Cazin, C. Vallee, H. OlivierꢀBourbigou and P. Braunstein, Chem.
Commun., 2008, 3983ꢀ3985.
23.
24.
A. A. Danopoulos, A. A. D. Tulloch, S. Winston, G. Eastham and M. B. Hursthouse,
Dalton Trans., 2003, 1009ꢀ1015.
F. E. Hahn, M. C. Jahnke, V. GomezꢀBenitez, D. MoralesꢀMorales and T. Pape,
Organometallics, 2005, 24, 6458ꢀ6463.
25.
26.
X. Liu and P. Braunstein, Inorg. Chem., 2013, 52, 7367ꢀ7379.
V. Go´mezꢀBenı´tez, R. n. A. Toscano and D. MoralesꢀMorales, Inorg. Chem.
Commun., 2007, 8, 1ꢀ6.
27.
28.
29.
30.
31.
32.
D. BenitoꢀGaragorri, V. Bocoke, K. Mereiter and K. Kirchner, Organometallics,
2006, 25, 3817ꢀ3823.
J.ꢀL. Niu, Q.ꢀT. Chen, X.ꢀQ. Hao, Q.ꢀX. Zhao, J.ꢀF. Gong and M.ꢀP. Song,
Organometallics, 2010, 29, 2148ꢀ2156.
M. A. SolanoꢀPrado, F. EstudianteꢀNegrete and D. MoralesꢀMorales, Polyhedron,
2010, 29, 592ꢀ600.
J. M. SerranoꢀBecerra, S. HernandezꢀOrtega and D. MoralesꢀMorales, Inorg. Chim.
Acta, 2010, 363, 1306ꢀ1310.
O. V. Ozerov, C. Guo and B. M. Foxman, J. Organomet. Chem., 2006, 691, 4802ꢀ
4806.
P. Kumar, M. M. Siddiqui, Y. Reddi, J. T. Mague, R. B. Sunoj and M. S. Balakrishna,
Dalton Trans., 2013, 42, 11385ꢀ11399.
33.
34.
35.
36.
37.
D. E. Herbert and O. V. Ozerov, Organometallics, 2011, 30, 6641ꢀ6654.
V. Pandarus and D. Zargarian, Organometallics, 2007, 26, 4321ꢀ4334.
D. M. Spasyuk and D. Zargarian, Inorg. Chem., 2010, 49, 6203ꢀ6213.
D. Gelman and S. Musa, ACS Catal., 2012, 2, 2456ꢀ2466.
M. Gagliardo, C. H. M. Amijs, M. Lutz, A. L. Spek, R. W. A. Havenith, F. Hartl, G.
P. M. van Klink and G. van Koten, Inorg. Chem., 2007, 46, 11133ꢀ11144.
N. a. EspinosaꢀJalapa, S. HernandezꢀOrtega, D. MoralesꢀMorales and R. Le Lagadec,
J. Organomet. Chem., 2012, 716, 103ꢀ109.
38.
39.
N. A. EspinosaꢀJalapa, S. HernandezꢀOrtega, X.ꢀF. Le Goff, D. MoralesꢀMorales, J.ꢀ
P. Djukic and R. Le Lagadec, Organometallics, 2013, 32, 2661ꢀ2673.
19

Dalton Transactions
Page 20 of 24
View Article Online
DOI: 10.1039/C4DT02810D
40.
41.
42.
43.
S. Bonnet, J. H. van Lenthe, M. A. Siegler, A. L. Spek, G. van Koten and R. J. M. K.
Gebbink, Organometallics, 2009, 28, 2325ꢀ2333.
S. Bonnet, M. Lutz, A. L. Spek, G. van Koten and R. J. M. K. Gebbink,
Organometallics, 2010, 29, 1157ꢀ1167.
S. Bonnet, M. Lutz, A. L. Spek, G. van Koten and R. J. M. K. Gebbink,
Organometallics, 2007, 27, 159ꢀ162.
M. Gagliardo, G. Rodriguez, H. H. Dam, M. Lutz, A. L. Spek, R. W. A. Havenith, P.
Coppo, L. De Cola, F. Hartl, G. P. M. van Klink and G. van Koten, Inorg. Chem.,
2006, 45, 2143ꢀ2155.
44.
45.
46.
B. M. J. M. Suijkerbuijk, D. J. Schamhart, H. Kooijman, A. L. Spek, G. van Koten
and R. J. M. K. Gebbink, Dalton Trans., 2010, 39, 6198ꢀ6216.
B. M. J. M. Suijkerbuijk, S. D. Herreras Martinez, G. van Koten and R. J. M. K.
Gebbink, Organometallics, 2008, 27, 534ꢀ542.
K. Fujimoto, T. Yoneda, H. Yorimitsu and A. Osuka, Angew. Chem. Int. Ed., 2014,
53, 1127ꢀ1130.
47.
48.
T. Kimura and Y. Uozumi, Organometallics, 2006, 25, 4883ꢀ4887.
M. S. Balakrishna, D. Suresh, A. Rai, J. T. Mague and D. Panda, Inorg. Chem., 2010,
49, 8790ꢀ8801.
49.
50.
D. Suresh, M. S. Balakrishna, K. Rathinasamy, D. Panda and S. M. Mobin, Dalton
Trans., 2008, 2812ꢀ2814.
P. Chandrasekaran, J. T. Mague and M. S. Balakrishna, Organometallics, 2005, 24,
3780ꢀ3783.
51.
52.
D. Suresh, M. S. Balakrishna and J. T. Mague, Dalton Trans., 2008, 3272ꢀ3274.
M. S. Balakrishna, R. Venkateswaran and J. T. Mague, Dalton Trans., 2010, 39,
11149ꢀ11162.
53.
54.
G. S. Ananthnag, S. Kuntavalli, J. T. Mague and M. S. Balakrishna, Inorg. Chem.,
2012, 51, 5919ꢀ5930.
M. S. Balakrishna, R. Venkateswaran and J. T. Mague, Inorg. Chem., 2009, 48, 1398ꢀ
1406.
55.
56.
P. Kommana and K. C. Kumara Swamy, Inorg. Chem., 2000, 39, 4384ꢀ4385.
D. Suresh, M. S. Balakrishna and J. T. Mague, Tetrahedron Lett., 2007, 48, 2283ꢀ
2285.
57.
G. R. Lief, D. F. Moser, L. Stahl and R. J. Staples, J. Organomet. Chem., 2004, 689,
1110–1121.
20

Page 21 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C4DT02810D
58.
59.
60.
61.
62.
63.
V. GomezꢀBenitez, O. BaldovinoꢀPantaleon, C. Herrera Alvarez, R. A. Toscano and
D. MoralesꢀMorales, Tetrahedron Lett., 2006, 47, 5059ꢀ5062.
A. Salah and D. Zargarian, Acta Crystallogr., Sect. E: Struct. Rep. Online, 2011, 67,
m437ꢀm439.
J. Zhang, C. M. Medley, J. A. Krause and H. Guan, Organometallics, 2010, 29, 6393ꢀ
6401.
K. A. Watson, F. L. Palmieri and J. W. Connell, Macromolecules, 2002, 35, 4968ꢀ
4974.
C.ꢀH. Chien, C.ꢀK. Chen, F.ꢀM. Hsu, C.ꢀF. Shu, P.ꢀT. Chou and C.ꢀH. Lai, Adv.
Funct. Mater., 2009, 19, 560ꢀ566.
H. Morimoto, T. Yoshino, T. Yukawa, G. Lu, S. Matsunaga and M. Shibasaki,
Angew. Chem. Int. Ed., 2008, 47, 9125ꢀ9129.
64.
65.
66.
A. L. Schwan, Chem. Soc. Rev., 2004, 33, 218ꢀ224.
K. Xu, F. Yang, G. Zhang and Y. Wu, Green Chem., 2013, 15, 1055ꢀ1060.
S. M. Rummelt, M. Ranocchiari and J. A. van Bokhoven, Org. Lett., 2012, 14, 2188ꢀ
2190.
67.
Y.ꢀL. Zhao, G.ꢀJ. Wu, Y. Li, L.ꢀX. Gao and F.ꢀS. Han, Chem. Eur. J., 2012, 18, 9622ꢀ
9627.
68.
69.
70.
M. Stankevic and A. Wlodarczyk, Tetrahedron, 2013, 69, 73ꢀ81.
K. Xu, H. Hu, F. Yang and Y. Wu, Eur J. Org. Chem., 2013, 2013, 319ꢀ325.
W. L. Armarego and D. D. Perrin, Purification of Laboratory Chemicals, 4th ed,
ButterworthꢁHeinemann Linacre House, Jordan Hill, Oxford, U. K., 1996.
T. Hamura, T. Hosoya, H. Yamaguchi, Y. Kuriyama, M. Tanabe, M. Miyamoto, Y.
Yasui, T. Matsumoto and K. Suzuki, Helv. Chim. Acta, 2002, 85, 3589ꢀ3604.
A. Bashall, E. L. Doyle, C. Tubb, S. J. Kidd, M. McPartlin, A. D. Woods and D. S.
Wright, Chem. Commun., 2001, 2542–2543.
71.
72.
73.
74.
75.
K. Moseley and P. M. Maitlis, J. Chem. Soc., Chem. Commun., 1971, 982ꢀ983.
L. Malatesta and C. Cariello, J. Chem. Soc., 1958, 2323ꢀ2328.
B. S. Furniss, A. J. Hannaford, P. W. G. Smith and A. R. Tatchell, Vogel's Textbook
of Practical Organic Chemistry, Fifth Edition, ELBS, England, 1989, 428ꢀ429.
BrukerꢁAXS, SMART, Version 5.625, Madison, WI,, 2000.
APEX2, version 2.1ꢁ0, BrukerꢁAXS, Madison, WI,, 2006.
G. W. Sheldrick, SADABS, versions 2.05 and 2007/2, University of Göttingen,
Germany, 2002.
76.
77.
78.
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Table 1. Selected bond lengths [Å] and bond angles [°] for 1 – 3, 5 and 6
bond lengths [Å]
bond angles [°]
1
2
3
5
6
1
2
3
5
6
P1–O1
P2–O2
P1–N1
P3–N2
P3–N5
C–I
1.694(3) 1.650(4)
1.708(3) 1.653(4)
1.686(3) 1.664(4)
1.740(3) 1.744(4)
1.666(3) 1.604(7)
2.091(3)
1.648(3) 1.647(3)
1.648(3) 1.657(3)
1.658(3) 1.670(4)
1.758(3) 1.650(4)
1.655(3) 1.650(4)
1.642(5)
1.652(5)
1.662(6)
1.725(7)
1.639(6)
N1–P1–N2 82.87(14) 84.4(2)
N1–P3–N2 79.67(14) 79.4(2)
N1–P3–N5 105.23(14) 103.8(3)
P1–N1–P3 98.36(15) 97.4(2)
84.97(14) 84.6(2)
84.2(3)
79.39(14) 80.34(19) 80.6(3)
103.85(16) 107.5(2)
97.83(15) 95.4(2)
106.6(3)
96.5(3)
P1–M–P2
I1–M–C
166.28(6) 162.20(4) 161.35(5) 162.01(6)
176.92(12) 174.79(9) 171.31(11) 170.64(18)
104.53(13) 103.97(9) 105.57(12) 104.88(18)
P1–M
2.1668(13) 2.2758(9) 2.2570(13) 2.2607(16
2.1621(12) 2.2910(9) 2.2901(12) 2.2826(15)
M–P1–O1
P1–M–C
P2–M
83.21(12) 81.12(9)
80.44(11) 80.68(19)
91.17(4) 90.43(5)
M–I1
2.5027(7)
1.868(4)
2.6608(4) 2.6724(9)
1.980(3) 1.993(5)
2.6123(10)
1.989(7)
P1–M1–I1
P2–M1–I1
M–I1–Cu1
P3–Cu1–I1
P3–Cu1–X
P4–Cu2–X
X–Cu1–X
X–Cu2–X
98.31(4)
95.37(4)
93.90(3)
M–C
103.88(3) 107.40(3) 107.52(5)
112.49(2)
Cu1–P3
Cu2–P4
Cu1–I1
Cu1–X2
Cu2–X2
Cu2–O3
2.2223(16) 2.218(2)
2.1958(14) 2.1738(18)
2.9303(12)
98.63(4)
122.49(5) 127.03(9)
126.98(4) 125.55(7)
103.42(3) 105.6(2)
109.15(3) 101.10(18)
2.6426(12) 2.461(7)
2.5595(10) 2.549(7)
2.212(12)
22

Page 23 of 24
Dalton Transactions
Table 2. Crystallographic Information for Compounds 1 – 3, 5 and 6.
1
2
3
5
6
Formula
C30H59IN6O2P4 C30H59IN6NiO2P4· C30H59IN6O2P4Pd· C60H118Cu4I6N12O4P8Pd2 C60H120Br4Cu4I2N12O5P8Pd2·
2CHCl3
1084.06
monoclinic
P121/n1 (No. 14)
16.6214(16)
15.2055(15)
19.0941(19)
90
2CHCl3
1131.75
monoclinic
CH2Cl2
2462.77
monoclinic
P121/n 1 (No. 14)
15.4735(8)
19.4221(10)
17.5182(9)
90
Formula Weight
Crystal System
Space group
a [Å]
b [Å]
c [Å]
786.61
Orthorhombic
Pca21 (No. 29)
28.754(3)
8.4632(8)
16.4274(15)
90
2547.78
monoclinic
P121/c1 (No. 14) P121/n 1 (No. 14)
15.3398(15)
16.6898(17)
18.9655(19)
90
15.390(4)
19.203(5)
18.045(5)
90
α [°]
β [°]
γ [°]
V [Å3]
90
90
3997.6(7)
4
1.307
91.530(1)
90
4824.1(8)
4
1.493
1.542
94.375(2)
90
4841.4(8)
4
1.553
1.519
111.990(4)
90
4945(2)
2
1.711
3.245
113.460(1)
90
4829.5(4)
2
1.694
3.757
Z
ρcalc [gcmꢀ3]
µ (MoꢀKα) [mmꢀ1]
F(000)
0.994
1640
2216
2288
2480
2440
T (K)
100
100
100
100
100
2θ range [°]
Total no. of reflns
No. of indep reflns 9838
Rint
R
wR
S
2.4ꢀ29.0
10480
1.8ꢀ27.9
102296
19001
2.0ꢀ28.3
106851
19796
0.052
0.0459
0.1020
1.17
1.8ꢀ28.2
84469
10524
0.054
0.0434
0.1037
1.03
1.8ꢀ27.9
82607
9073
0.0413
0.095
0.068
0.0382
0.0929
1.131
0.0563
0.1020
1.06
0.0627
0.1949
1.05
2
2
Where w = 1/[σ2(Fo ) + (0.0241P)2 + 1.2733P], where P = (Fo + 2Fc2)/3
23

Dalton Transactions
Page 24 of 24
View Article Online
DOI: 10.1039/C4DT02810D
Synopsis and graphics for the contents page
Cyclodiphosphazane
based
pincer
ligand,
2,6-{µ-
(tBuN)P(tBuHN)PO}2C6H3: NiII, PdII, PtII and CuI complexes, and catalytic
studies
Guddekoppa S. Ananthnaga, Joel T. Magueb and Maravanji S. Balakrishna∗,a
Pincer complexes derived from difunctional cyclodiphosphazanes and their multimetallic
macrocycles and catalytic studies have been described.
∗ Author to whom correspondence should be addressed. Eꢀmail: krishna@chem.iitb.ac.in,
msb_krishna@iitb.ac.in (M. S. Balakrishna); Fax: +91ꢀ22ꢀ5172ꢀ3480/2576ꢀ7152.
24