Copper(I) coordination polymers [{Cu(μ-X)}2{RP(μ-N tBu)}2]n (R = OC6H4OMe-o; X = Cl, Br, and I) and their reversible conversion into mononuclear complexes [CuX{(RP(μ-NtBu))2}2]: Synthesis and structural characterization

Article abstract of DOI:10.1021/ic060464j

The reactions of cyclodiphosphazane cis-[^tBuNP(OC ₆H₄OMe-o)]₂ (1) with 2 equiv of CuX in acetonitrile afforded one-dimensional Cu^I coordination polymers [Cu₂X₂{^tBuNP(OC₆H ₄OMe-o)}₂]_n (2, X = Cl; 3, X = Br; 4, X = I). The crystal structures of 2 and 4 reveal a zigzag arrangement of [P(μ-N) ₂P] and [Cu(μ-X)₂Cu] units in an alternating manner to form one-dimensional Cu^I coordination polymers. The reaction between 1 and CuX in a 2:1 ratio afforded mononuclear tricoordinated copper(I) complexes of the type [CuX{(^tBuNP(OC₆H₄OMe-o)) ₂}₂] (5, X = Cl; 6, X = Br; 7, X = I). The single-crystal structures were established for the mononuclear copper(I) complexes 5 and 6. When the reactant ratios are 1:1, the formation of a mixture of polymeric and mononuclear products was observed. The Cu^I polymers (2-4) were converted into the mononuclear complexes (5-7) by reacting with 3 equiv of 1 in dimethyl sulfoxide. Similarly, the mononuclear complexes (5-7) were converted into the corresponding polymeric complexes (2-4) by reacting with 3 equiv of copper(I) halide under mild reaction conditions.

Full text of DOI:10.1021/ic060464j

Inorg. Chem. 2006, 45, 6678−6683
Copper(I) Coordination Polymers [
OC6H4OMe-o; X Cl, Br, and I) and Their Reversible Conversion into
{Cu(µ-X)}2{RP(µ }2]n (R )
-NtBu)
)
Mononuclear Complexes [CuX
Structural Characterization
{(RP(µ }2]: Synthesis and
-NtBu))2
P. Chandrasekaran,† Joel T. Mague,†,‡ and Maravanji S. Balakrishna*,†
Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai 400 076, India, and
Department of Chemistry, Tulane UniVersity, New Orleans, Louisiana 70118
Received March 18, 2006
The reactions of cyclodiphosphazane cis-[tBuNP(OC6H4OMe-o)]2 (1) with 2 equiv of CuX in acetonitrile afforded
one-dimensional CuI coordination polymers [Cu2X2 tBuNP(OC6H4OMe-o)
2]n (2, X Cl; 3, X Br; 4, X I). The
crystal structures of 2 and 4 reveal a zigzag arrangement of [P( -N)2P] and [Cu( -X)2Cu] units in an alternating
manner to form one-dimensional CuI coordination polymers. The reaction between 1 and CuX in a 2:1 ratio afforded
mononuclear tricoordinated copper(I) complexes of the type [CuX 2] (5, X Cl; 6, X
(tBuNP(OC6H4OMe-o))2
Br; 7, X I). The single-crystal structures were established for the mononuclear copper(I) complexes 5 and 6.
When the reactant ratios are 1:1, the formation of a mixture of polymeric and mononuclear products was observed.
The CuI polymers (2
4) were converted into the mononuclear complexes (5 7) by reacting with 3 equiv of 1 in
dimethyl sulfoxide. Similarly, the mononuclear complexes (5 7) were converted into the corresponding polymeric
complexes (2 4) by reacting with 3 equiv of copper(I) halide under mild reaction conditions.
{
}
)
)
)
µ
µ
{
}
)
)
)
−
−
−
−
Introduction
the linear propagation of a P2N2 chain that would have led
to the formation of very interesting poly(phosph(III)azanes)
of the type VI (see Chart 1). Although the relationship
between the monomer/dimer of P-N compounds (RNd
PR′t[RP(µ-NR′)]2) with bulky R groups is compared to that
between ethene/cyclobutane,8 cyclodiphosphazanes forming
the polymers (type VII) similar to polyethenes or polyphos-
phazenes (VIII) are unlikely because coordinatively unsatur-
While the chemistry of cyclodiphosphazanes or diaza-
diphosphetidines has been an active field of research for the
last 3 decades,1 this saturated P2N2 ring system has attracted
increased attention in recent years because of its excellent
synthetic utility in the design of macrocyles, in coordination
chemistry as neutral2 and anionic ligands,3 and also as
catalysts in ethene polymerization reactions.4 Because of
the preferential cis orientation of the substituents on the P
atoms of the cyclodiphosphazane ring, treatment with ap-
propriate linkers (Q) facilitates the formation of simple
monomeric (I) derivatives5 or dimeric6 to pentameric mac-
rocycles (II-V)7 through a “coiling process”, thus preventing
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* To whom correspondence should be addressed. E-mail: krishna@
chem.iitb.ac.in. Phone: (91) 22-2576-7181. Fax: (91) 22 2572-3480.
† Indian Institute of Technology.
‡ Tulane University.
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Academic Press: London, 1987; Vol. II, pp 467-496. (b) Keat, R.
Top. Curr. Chem. 1982, 102, 89-126. (c) Balakrishna, M. S.; Reddy,
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6678 Inorganic Chemistry, Vol. 45, No. 17, 2006
10.1021/ic060464j CCC: $33.50
© 2006 American Chemical Society
Published on Web 07/29/2006

Poly(cyclodiphosph(III)azanes)
Chart 1
Scheme 1
rigid P-donor ligands have been utilized for constructing
polynuclear metal complexes because of the lack of avail-
ability of the latter.10 Among the transition metals, CuI
exhibits many interesting coordination architectures ranging
from simple complexes to multinuclear cages and coordi-
nation polymers by the formation of dimeric and trimeric
[Cu(µ-X)]n units.
Recently, we have exploited the cis conformation of
these saturated P2N2 rings to make di-, tri-, or tetranuclear
metallomacrocycles with cyclodiphosphazanes exhibiting
monodentate, bridged bidentate, and chelating tetradentate
coordination modes.11,12 In this paper, we report the first
examples of coordination polymers of cyclodiphosphazanes
(type IX) using [Cu(µ-X)]2 as a template. We also describe
the formation of mononuclear CuI complexes containing two
monodentate cyclodiphosphazanes and their reversible trans-
formation into the corresponding coordination polymers.
ated p-block elements require bulky substituents to stabilize
π bonds. In the absence of π bonding, they prefer to form
cyclic oligomers (Scheme 1).8 However, the rigid cis isomers
can form coordination polymers of the type IX when treated
with the appropriate transition metals.
The main advantage of using such rigid units is their ability
to form macrocyclic and polymeric structures with metal
centers.9 Many more rigid N-donor ligands such as bis-
(pyridines) and S-donor ligands such as poly(thiophenes) than
Results and Discussion
Synthesis. Treatment of cis-[tBuNP(OC6H4OMe-o)]2 (1)
with 2 equiv of CuX (X ) Cl, Br, and I) in acetonitrile leads
to the formation of CuI coordination polymers 2-4, respec-
tively, in good yield (Scheme 2). The chloro and bromo
derivatives are precipitated from the reaction mixture as
insoluble white solids, whereas the corresponding iodo
complex 4 is soluble in acetonitrile and crystallizes from the
(7) (a) Bashall, A.; Doyle, E. L.; Tubb, C.; Kidd, S. J.; McPartlin, M.;
Woods, A. D.; Wright, D. S. Chem. Commun. 2001, 2542-2543. (b)
Bashall, A.; Bond, A. D.; Doyle, E. L.; Garcia, F.; Kidd, S.; Lawson,
G. T.; Parry, M. C.; McPartlin, M.; Woods, A. D.; Wright, D. S.
Chem.sEur. J. 2002, 3377-3385. (c) P. Kommana, P.; Kumara
Swamy, K. C. Inorg. Chem. 2000, 39, 4384-4385. (d) Garcia, F.;
Goodman, J. M.; Kowenicki, R. A.; Kuzu, I.; McPartlin, M.; Silva,
M. A.; Riera, L.; Woods, A. D.; Wright, D. S. Chem.sEur. J. 2004,
10, 6066-6072. (e) Garc´ıa, F.; Kowenicki, R. A.; Kuzu, I.; Riera, L.;
McPartlin, M.; Wright, D. S. Dalton. Trans. 2004, 2904-2909. (f)
Garcia, F.; Goodman, J. M.; Kowenicki, R. A.; McPartlin, M.; Riera,
L.; Silva, M. A.; Wirsing, A.; Wright, D. S. Dalton Trans. 2005,
1764-1773. (g) Kommana, P.; Vittal, J. J.; Kumara Swamy, K. C.
Polyhedron 2003, 22, 843-847.
(8) (a) Burford, N.; Cameron, T. S.; Conroy, K. D.; Ellis, B.; Lumsden,
M.; Macdonald, C. L. B.; McDonald, R.; Phillips, A. D.; Ragogna, P.
J.; Schurko, R. W.; Walsh, D.; Wasylishen, R. E. J. Am. Chem. Soc.
2002, 124, 14012-14013. (b) Burford, N.; Dyker, C. A.; Phillips, A.
D.; Spinney, H. A.; Deckon, A.; McDonald, R.; Ragogna, P. J.;
Rheingold, A. L. Inorg. Chem. 2004, 43, 7502-7507. (c) Garcia, F.;
Kowenicki, R. A.; Wright, D. S. Dalton Trans. 2005, 2495-2496.
(9) (a) Schubert, U. S.; Eschbaumer, C. Angew. Chem., Int. Ed. 2002,
41, 2892-2926. (b) Nguyen, P.; Gomez-Elipe, P.; Manners, I. Chem.
ReV. 1999, 99, 1515-1548. (c) Holliday, B. J.; Mirkin, C. A. Angew.
Chem., Int. Ed. 2001, 40, 2022-2043.
(10) (a) Kitagawa, S.; Kitaura, R.; Noro, S. Angew. Chem., Int. Ed. 2004,
43, 2334-2375. (b) Brandys, C. M.; Jennings, C. M.; Puddephatt, R.
J. J. Chem. Soc., Dalton Trans. 2000, 4601-4610. (c) Myrex, R. D.;
Colbert, C. S.; Gray, G. M.; Duffey, C. H. Organometallics 2004, 23,
409-415.
(11) Chandrasekaran, P.; Mague, J. T.; Balakrishna, M. S. Organometallics
2005, 24, 3780-3783.
(12) Chandrasekaran, P.; Mague, J. T.; Balakrishna, M. S. Inorg. Chem.
2005, 44, 7925-7932.
Inorganic Chemistry, Vol. 45, No. 17, 2006 6679

Chandrasekaran et al.
Scheme 2
Figure 1. Molecular structure of 2. Thermal ellipsoids are drawn at the
50% probability level. Uncoordinated solvent molecules, H atoms, and
substituents on P and N have been omitted for clarity.
Figure 2. Molecular structure of 4. Thermal ellipsoids are drawn at the
50% probability level. Uncoordinated solvent molecules, H atoms, and
substituents on P and N have been omitted for clarity.
mother liquor at room temperature. However, these com-
plexes are soluble in hot dimethyl sulfoxide (DMSO), which
allowed us to record their NMR spectra. The 31P NMR
spectra of complexes 2-4 show single resonances at 119.1,
115.4, and 114.2 ppm, respectively.
The interaction of 1 with CuX in a 2:1 ratio in acetonitrile
affords highly soluble tricoordinated CuI complexes 5 (X )
Cl), 6 (X ) Br), and 7 (X ) I), with cyclodiphosphazane
showing a monodentate mode of coordination. The 31P NMR
spectra of complexes 5-7 consist of two broad signals due
to the presence of both coordinated and uncoordinated P
centers. The signals due to the coordinated P appear at 110.3,
108.6, and 107.2 ppm, whereas the uncoordinated P centers
resonate at 134.9, 139.6, and 142.5 ppm, respectively.
2
Surprisingly, in all of these complexes (5-7), no JPP was
observed even at -50 °C and only two sharp singlets were
observed. Similar results were also observed in the previously
reported PdII and RhI complexes of the same ligand.12 The
1H NMR spectra of 5-7 recorded at room temperature show
a single resonance for the OMe groups around 3.80 ppm,
Figure 3. Molecular structure of 5. Thermal ellipsoids are drawn at the
50% probability level. H atoms have been omitted for clarity.
1
while at low temperature (-50 °C), the H NMR spectrum
of 7 shows two different signals at 3.84 and 3.79 ppm for
the OMe groups. The mass spectral data show a peak at m/z
963.33 for all three complexes as a base peak, which
corresponds to a M-X ion (X ) Cl, Br, and I). Single-crystal
X-ray structure determinations established the structures of
complexes 2 and 4-6.
The reaction of 1 with 1 equiv of CuX afforded a mixture
of both polymeric and tricoordinated complexes in all cases
(X ) Cl, Br, and I), as indicated by their 31P NMR spectral
data. Wright and co-workers have reported13 an exo-
metalated tetranuclear CuI complex obtained in a reaction
of CuCl with in situ generated dimer [(2-C5H4N)NP}2O}]2,
in the presence of an excess of pyridine, which by blocking
the two coordination sites on the CuI centers probably would
have terminated the possibility of the formation of similar
polymeric products.
Figure 4. Molecular structure of 6. Thermal ellipsoids are drawn at the
50% probability level. H atoms have been omitted for clarity.
The crystallographic data and the details of structure deter-
mination are given in Table 1. The selected bond distances
and bond angles are listed in Tables 2 and 3.
The colorless crystals of 2 were obtained from a DMSO
solution at room temperature. The core structure of 2 consists
of four-membered [RP(µ-NtBu)]2 and [Cu(µ-Cl)2Cu] units
Crystal Structures of Complexes 2 and 4-6. Molecular
structures of CuI complexes 2 and 4-6 with their atom
numbering schemes are shown in Figures 1-4, respectively.
(13) Bond, A. D.; Doyle, E. L.; Garc´ıa, F.; Kowenicki, R. A.; McPartlin,
M.; Riera, L.; Wright, D. S. Chem. Commun. 2003, 2990-2991.
6680 Inorganic Chemistry, Vol. 45, No. 17, 2006

Poly(cyclodiphosph(III)azanes)
Table 1. Crystallographic Data for 2 and 4-6
2‚DMSO
4‚CH3CN
5
6
formula
fw
cryst syst
space group
a, Å
C24H38Cl2Cu2N2O5P2S
804.71
triclinic
P1h
10.3726(8)
12.2730(10)
15.4980(10)
68.3010(10)
85.1400(10)
77.5260(10)
1789.8(2)
2
C24H35Cu2I2N3O4P2
913.44
monoclinic
Cc
13.4780(10)
18.1040(10)
15.015(10)
90
108.4950(10)
90
3474.5(4)
4
1.746
3.128
1792
C44H64ClCuN4O8P4
999.87
monoclinic
P21
9.5024(7)
18.7330(10)
14.0920(10)
90
96.2170(10)
90
2493.7(3)
2
1.332
0.672
1052
C44H64BrCuN4O8P4
1044.32
monoclinic
P21
9.6070(10)
18.694(2)
14.084(2)
90
96.547(2)
90
2512.9(5)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
F
calc, g cm-3
1.493
1.582
832
1.380
1.409
1088
µ(Mo Ka), mm-1
F(000)
cryst size (mm3)
T (K)
0.12 × 0.14 × 0.26
0.16 × 0.16 × 0.26
0.13 × 0.15 × 0.16
0.06 × 0.12 × 0.14
293
100
100
100
2θ range, deg
total no. of reflns
no. of indep reflns
GOF (F 2)
1.4-27.8
15 924
8159 [Rint ) 0.017]
1.05
0.0307
0.0840
2.0-28.3
15 345
7781 [Rint ) 0.021]
1.04
0.0311
0.0752
1.5-28.3
22 382
11 579 [Rint ) 0.028]
1.00
0.0351
0.0793
1.5-28.3
22 523
11 429 [Rint ) 0.038]
0.98
0.0418
0.0844
R1a
wR2b
2
2
2
2
2
2
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. b wR2 ) {[∑w(Fo - Fc )/∑w(Fo )2]}1/2; w ) 1/[σ2(Fo ) + (xP)2], where P ) (Fo + 2Fc )/3.
Table 2. Selected Bond Distances (Å) and Bond Angles (deg) for 2
and 4
Table 3. Selected Bond Distances (Å) and Bond Angles (deg) for 5
and 6
bond distance (Å)
bond angle (deg)
bond distance (Å)
bond angle (deg)
Complex 5
P1-Cu-Cl
Complex 2
P1-Cu1-Cl1
Cu-P1
2.197(1)
2.244(1)
2.216(1)
1.627(2)
1.667(2)
1.629(2)
1.667(2)
1.692(2)
1.692(2)
1.703(2)
1.729(2)
1.690(2)
1.684(2)
1.704(3)
1.720(2)
1.391(3)
1.394(3)
1.404(3)
1.385(3)
125.58(3)
104.16(3)
130.11(2)
104.38(6)
114.58(6)
126.43(15)
117.94(14)
125.55(16)
117.96(14)
97.79(10)
96.80(10)
82.92(9)
Cu1-P1
2.141(1)
2.192(1)
2.279(1)
2.294(1)
2.363(2)
2.376(5)
2.358(1)
1.486(2)
1.698(2)
1.691(2)
1.696(2)
1.699(2)
2.947
130.37(2)
129.63(2)
99.73(2)
80.27(2)
122.31(2)
98.54(2)
93.74(2)
117.32(2)
119.30(2)
119.97(7)
86.26(2)
96.32(8)
96.50(8)
82.69(8)
82.52(8)
Cu-P3
Cu-Cl
P1-O1
P2-O3
P3-O5
P4-O7
P1-N1
P1-N2
P2-N1
P2-N2
P3-N3
P3-N4
P4-N3
P4-N4
O1-C9
O3-C16
O5-C31
O7-C38
P3-Cu-Cl
P1-Cu-P3
Cu-P1-O1
Cu-P3-O5
P1-O1-C9
P2-O3-C16
P3-O5-C31
P4-O7-C38
P1-N1-P2
P1-N2-P2
N1-P1-N2
N1-P2-N2
P3-N3-P4
P3-N4-P4
N3-P3-N4
N3-P4-N4
Cu2-P2
Cu1-Cl1
Cu1-Cl1i
Cu2-Cl2
Cu2-Cl2i
Cu2-S1
S1-O5
P1-Cu1-Cl1i
Cl1-Cu1-Cl1i
Cu1-Cl1-Cu1i
P2-Cu2-S1
S1-Cu2-Cl2
Cl2-Cu2-Cl2i
P(2)-Cu2-Cl2i
Cl2-Cu2-P2
Cu2-S1-O5
Cu2-Cl2-Cu2i
P1-N1-P2
P1-N1
P1-N2
P2-N1
P2-N2
81.49(9)
Cu1‚‚‚Cu1i
Cu2‚‚‚Cu2i
P1-N2-P2
97.23(10)
96.85(10)
83.01(9)
3.240
N1-P1-N2
N1-P2-N2
Complex 4
81.50(9)
Cu1-P1
Cu2-P2i
Cu1-I1
Cu1-I2
Cu2-I1
Cu2-I2
Cu1-N3
P1-N1
2.206(1)
2.198(2)
2.643(1)
2.669(2)
2.552(1)
2.555(1)
2.041(4)
1.705(3)
1.706(4)
1.687(4)
1.690(3)
3.118
P1-Cu1-N3
P1-Cu1-I2
P1-Cu1-I1
I1-Cu1-I2
I1-Cu2-I2
N3-Cu1-I1
Cu1-I1-Cu2
Cu1-I2-Cu2
Cu1-N3-C23
P2i-Cu2-I1
P2i-Cu2-I2
P1-N1-P2
P1-N2-P2
N1-P1-N2
N1-P2-N2
106.13(11)
115.32(4)
117.31(4)
102.54(2)
108.47(2)
113.85(12)
73.74(2)
Complex 6
Cu-P1
Cu-P3
Cu-Br
P1-O1
P2-O3
P3-O5
P4-O7
P1-N1
P1-N2
P2-N1
P2-N2
P3-N3
P3-N4
P4-N3
P4-N4
O1-C9
O3-C16
O5-C31
O7-C38
2.241(1)
2.203(2)
2.350(1)
1.628(2)
1.668(2)
1.623(2)
1.667(2)
1.687(3)
1.688(3)
1.708(3)
1.720(3)
1.685(3)
1.684(3)
1.707(3)
1.727(3)
1.399(4)
1.388(4)
1.397(4)
1.385(4)
P1-Cu-Br
P3-Cu-Br
P1-Cu-P3
Cu-P1-O1
Cu-P3-O5
P1-O1-C9
P2-O3-C16
P3-O5-C31
P4-O7-C38
P1-N1-P2
P1-N2-P2
N1-P1-N2
N1-P2-N2
P3-N3-P4
P3-N4-P4
N3-P3-N4
N3-P4-N4
104.81(3)
125.56(3)
129.44(4)
113.62(9)
104.05(9)
126.66(19)
118.61(19)
126.55(20)
117.78(18)
97.32(14)
96.79(14)
82.98(13)
81.42(13)
97.50(15)
96.77(15)
82.69(14)
80.84(14)
73.25(2)
P1-N2
162.17(43)
127.61(4)
123.75(4)
96.5(2)
96.3(2)
81.76(18)
82.74(18)
P2-N1
P2-N2
Cu1‚‚‚Cu2
arranged alternately in a zigzag fashion to form a one-
dimensional coordination polymer. The molecule is made
up of two different kinds of [Cu(µ-Cl)2Cu] units, which dif-
fer in their coordination number at the CuI centers. In the
[Cu1(µ-Cl1)2Cu1i] dimeric unit, the Cu is tricoordinated with
the coordination sites occupied by a P atom of the cyclo-
diphosphazane and two bridging Cl atoms. The geometry
around the metal center is trigonal planar. The bond angle
P1-Cu1-Cl1 [130.37(2)°] is larger than Cl1-Cu1-Cl1i
[99.73(2)°]. The P1-Cu1-Cl1i bond angle is almost identi-
cal with P1-Cu1-Cl1. In the [Cu2(µ-Cl2)2Cu2i] dimeric
Inorganic Chemistry, Vol. 45, No. 17, 2006 6681

Chandrasekaran et al.
unit, the geometry around the Cu center is distorted
tetrahedral, with DMSO occupying the fourth coordination
site and the angles about Cu varying from 122.31(2)° for
S1-Cu2-P2 to 98.54(2)° for Cl2-Cu2-S1. The nonbond-
ing Cu1‚‚‚Cu1i distance is 2.947 Å, whereas the Cu2‚‚‚Cu2i
distance is 3.240 Å. This difference arises as a result of the
increase in the coordination number from 3 to 4. In both
cases, the Cu‚‚‚Cu distances are noticeably greater than the
sum of the van der Waals radii for the CuI ion, which
confirms the nonexistence of metallophilic interactions in
polymer 2. The Cu1-P1 and Cu1-Cl1 bond distances are
shorter than Cu2-P2 and Cu2-Cl2, and this difference is
again due to the tri- and tetracoordinated nature of the two
CuI centers. The Cu2-S1 bond distance is 2.358(1) Å, which
indicates the coordination of DMSO to the CuI center.14 The
weak interaction between Cu1 and O2 atoms was observed
for compound 2, which is evident from the bond distance of
2.677 Å. The [Cu(µ-Cl)2Cu] units are planar, whereas the
P2N2 ring is slightly puckered (æ2 ) 0.157 Å)15 in order to
form a strain-free zigzag polymeric structure. Because of the
puckering of the P2N2 ring, the sum of the angles around N
is 354.33(10)°.
The crystals of 4 suitable for X-ray diffraction studies were
grown from an acetonitrile solution at room temperature. The
core structure of 4 is similar to that of its chloro analogue 2.
The polymer 2 contains two different [Cu(µ-Cl)2Cu] dimeric
units, with the Cu centers in a given unit having identical
geometry. In the case of 4, only one type of [Cu(µ-I)2Cu]
dimeric unit exists and the two Cu centers have different
geometries. In the molecular structure of 4, Cu1 is in a
distorted tetrahedral environment consisting of two bridging
I atoms, a P atom from cyclodiphosphazane, and a N atom
from the coordinated acetonitrile molecule. The geometry
around the Cu2 center is distorted trigonal planar. The
nonbonded Cu‚‚‚Cu distance is 3.118 Å. The four-mem-
bered [Cu(µ-I)2Cu] unit in 4 is slightly puckered (æ2 ) 0.238
Å),15 whereas in the case of 2, both of the four-membered
[Cu(µ-Cl)2Cu] rings are planar. The presence of two different
geometries in one dimeric unit in 4 may be responsible for
the puckering. The diazadiphosphetidine ring is also puckered
(æ2 ) -0.186 Å).15 The Cu-P bond distances in 4 are
slightly longer as compared to the same in the chloro
derivative.
the similar angles reported16 for tricoordinated complexes
of a less bulkier phosphine ligand like PPh3 [125.48(7)°] and
bulkier ligands such as PCy3 [134.44(8)°] and PBn3 [136.53-
(2)°]. The P1-Cu-P3 bond angles are larger than the
P1-Cu-Cl and P3-Cl-Cu bond angles in the same
molecule. The P-Cu and Cu-X bond distances are in good
agreement with the literature values for tricoordinated copper-
(I) phosphine complexes.17 In 5, the puckering parameters
(æ2)15 for the P1N1P2N2 and P3N3P4N4 rings are respectively
-0.112 and +0.132 Å, while in 6, the corresponding values
are +0.137 and -0.166 Å.
The interesting feature of these metal-containing polymers
is that they undergo depolymerization (reversible coordina-
tion) in the presence of added ligands to give simple
complexes, a process that is not facile with covalently bonded
polymers.18 This led to our study of the interconversion
between poly- and mononuclear complexes in NMR tube
reactions using appropriate reactants. Polymer 4 was dis-
solved in hot DMSO-d6 in an NMR tube, 3 equiv of 1 was
added, and the reaction was monitored through 31P NMR
spectroscopy. Within 1 h, the peak at 114.2 ppm disappeared
and two new peaks appeared at 142.5 and 107.2 ppm,
indicating the complete conversion of polymer 4 into the
mononuclear complex [CuI{(tBuNP(OC6H4OMe-o))2}2] (7).
Similarly, the complete conversion of the mononuclear
complex 7 into polymer 2 was also observed upon the
addition of 3 equiv of CuI in DMSO-d6.
Conclusions
We have reported the first examples of CuI coordination
polymers of cyclodiphosphazanes, which undergo rare
reversible transformations into the corresponding mono-
nuclear complexes. Although cis conformers are not kineti-
cally suited for extending the linear propagation to give the
coordination polymers, the formation of rhombic [Cu(µ-Cl)]2
units during the reaction and their flexible orientations and
variable coordination numbers of CuI centers facilitated the
formation of coordination polymers.
Experimental Section
General Procedures. All manipulations were performed under
rigorously anaerobic conditions using high vacuum manifolds and
Schlenk techniques. All of the solvents were purified by conven-
tional procedures and distilled prior to use.19 The compounds cis-
[tBuNP(OC6H4OMe-o)]2 (1),11 copper(I) chloride, and copper(I)
bromide20 were prepared according to the published procedure.
Copper(I) iodide was purchased from commercial sources and used
as received.
The single crystals of 5 and 6 were grown from an
acetonitrile solution at -30 °C. In both complexes, the
CuI atom occupies the center of a distorted trigonal plane,
the corners are occupied by two P atoms from two dif-
ferent cyclodiphosphazane units, the Cl atom in complex
5, and the Br atom in complex 6. Of the two different kinds
of geometrical arrangements possible for planar tricoordi-
nated CuI (T- and Y-shaped), complexes 5 and 6 prefer the
latter. The P1-Cu-P3 angles are 130.11(2)° for 5 and
129.44(4)° for 6, which indicates that the identity of the
halogen atom does not have a great influence on the geometry
of the molecule. The P1-Cu-P3 bond angles lie between
(16) Bowmaker, G. A.; Boyd, S. E.; Hanna, J. V.; Hart, R. D.; Healy, P.
C.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 2002,
2722-2730.
(17) Bowmaker, G. A.; Engelhardt, L. M.; Healy, P. C.; Kildea, J. D.;
Papasergio, R. I.; White, A. H. Inorg. Chem. 1987, 26, 3533-3538.
(18) Dobrawa, R.; Wurthner, F. J. Polym. Sci., Part A: Polym. Chem. 2005,
43, 4981-4995.
(19) Armarego, W. L. F.; Perrin, D. D. Purification of Laboratory
Chemicals, 4th ed.; Butterworth-Heinemann Linacre House: Jordan
Hill, Oxford, England, 1996.
(14) Tiethof, J. A.; Stalick, J. K.; Corfield, P. W. R.; Meek, D. W. Chem.
Commun. 1972, 1141-1142.
(15) Cremer, D.; Pople, J. A. J. Am. Chem. Soc. 1975, 97, 1354-1358.
(20) Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A. R.
Vogel’s Textbook of Practical Organic Chemistry, 5th ed.; ELBS:
London, England, 1989; pp 428-429.
6682 Inorganic Chemistry, Vol. 45, No. 17, 2006

Poly(cyclodiphosph(III)azanes)
1
Spectroscopy. The H and 31P{1H} NMR (δ in ppm) spectra
C44H64N4O8P4CuBr: C, 50.60; H, 6.17; N, 5.36. Found: C, 50.62;
were recorded using a Varian Mercury Plus spectrometer operating
at the appropriate frequencies using tetramethylsilane and 85%
H3PO4 as internal and external references, respectively. Microanaly-
ses were performed on a Carlo Erba model 1112 elemental analyzer.
Mass spectrometry experiments were carried out using a Waters
Q-Tof micro-YA-105. Melting points were recorded in capillary
tubes and are uncorrected.
H, 6.32; N, 5.52. MS (EI): m/z 963.33 (M - Br).
Synthesis of [CuI{(tBuNP(OC6H4OMe-o))2}2] (7). The syn-
thesis was the same as that for 5, except using CuI (34 mg, 0.181
mmol) and 1 (163 mg, 0.363 mmol). Yield: 165 mg (84%). Mp:
1
156-158 °C. H NMR (400 MHz, CDCl3, 25 °C): δ 7.25-6.82
(m, Ph, 16H), 3.81 (s, OMe, 12H), 2.00 (s, CH3CN, 3H), 1.45 (s,
1
tBu, 36H). H NMR (300 MHz, CDCl3, -50 °C): δ 7.86-6.81
Synthesis of [Cu2Cl2{tBuNP(OC6H4OMe-o)}2]n (2). An aceto-
nitrile solution (10 mL) of CuCl (34 mg, 0.35 mmol) was added
dropwise to an acetonitrile (10 mL) solution of 1 (79 mg, 0.175
mmol) at room temperature with stirring. A white precipitate was
separated out from the reaction mixture immediately after the
addition. Then the stirring was continued for a further 4 h, and the
precipitate was isolated by filtration. The solid was washed with 2
× 5 mL of diethyl ether and dried under reduced pressure. Yield:
98 mg (87%). Mp: 260-262 °C (dec). 1H NMR (400 MHz,
DMSO-d6): δ 7.33-6.86 (m, Ph, 8H), 3.78 (s, OMe, 6H), 1.39 (s,
tBu, 18H). 31P{1H} NMR (121 MHz, DMSO-d6): δ 119.1 (br s).
Anal. Calcd for C22H32N2O4P2Cu2Cl2: C, 40.74; H, 4.97; N, 4.32.
Found: C, 40.83; H, 4.80; N, 4.19.
(m, Ph, 16H), 3.84 (s, OMe, 6H), 3.79 (s, OMe, 6H), 2.09 (s,
CH3CN, 3H), 1.48 (s, tBu, 36H). 31P{1H} NMR (161 MHz, CDCl3,
25 °C): δ 142.5 (br s), 107.2 (br s). 31P{1H} NMR (121 MHz,
CDCl3, -50 °C): δ 138.8 (s), 101.9 (s). Anal. Calcd for
C44H64N4O8P4CuICH3CN: C, 48.78; H, 5.96; N, 6.18. Found: C,
48.55; H, 6.19; N, 6.08. MS (EI): m/z 963.4 (M - I).
X-ray Crystallography. Crystals of 2 and 4-6 were mounted
in a CryoLoop with a drop of Paratone oil and placed in the cold
N2 stream of the Kryoflex attachment of the Bruker APEX CCD
diffractometer. For each, a full sphere of data were collected using
606 scans in ω (0.3° per scan) at æ ) 0, 120, and 240° using the
SMART software package.21 The raw data were reduced to F2 values
using the SAINT+ software,22 and global refinements of unit cell
parameters employing 5931-7305 reflections chosen from the full
data sets were performed. Multiple measurements of equivalent
reflections provided the basis for empirical absorption corrections
as well as corrections for any crystal deterioration during the data
collection (SADABS23). The structures were solved by direct
methods and refined by full-matrix least-squares procedures using
the SHELXTL program package.24 H atoms were placed in
calculated positions [C-H ) 0.95 Å (aromatic rings) or 0.98 Å
(methyl groups)] and included as riding contributions with isotropic
displacement parameters 1.2 (aromatic rings) or 1.5 (methyl groups)
times those of the attached non-H atoms.
Synthesis of [Cu2Br2{tBuNP(OC6H4OMe-o)}2]n (3). The syn-
thesis was the same as that for 2, except using CuBr (80 mg,
0.559 mmol) and 1 (120 mg, 0.278 mmol). Yield: 180 mg (90%).
Mp: 254-256 °C (dec). 1H NMR (400 MHz, DMSO-d6): δ 7.37-
t
6.87 (m, Ph, 8H), 3.78 (s, OMe, 6H), 1.41 (s, Bu, 18H). 31P{1H}
NMR (DMSO-d6, 161 MHz): δ 115.4 (br s). Anal. Calcd for
C22H32N2O4P2Cu2Br2: C, 35.83; H, 4.37; N, 3.79. Found: C, 35.92;
H, 4.48; N, 3.83.
Synthesis of [Cu2I2{tBuNP(OC6H4OMe-o)}2]n (4). An aceto-
nitrile solution (10 mL) of CuI (283 mg, 1.49 mmol) was added
dropwise to a 10-mL acetonitrile solution of 1 (335 mg, 0.74 mmol)
at room temperature. The reaction mixture was stirred for 6 h and
then concentrated to 10 mL. Allowing the mixture to set at room
temperature for a day afforded the product as colorless crystals.
Acknowledgment. We are grateful to the Department of
Science and Technology, New Delhi, India, for funding
through Grant SR/S1/IC-05/2003. P.C. thanks CSIR for
Research Fellowship (JRF & SRF). We also thank RSIC,
Mumbai, India, and Department of Chemistry Instrumenta-
tion Facilities, Bombay, India, for spectral and analytical data,
and J.T.M. thanks the Louisiana Board of Regents through
Grant LEQSF(2002-03)-ENH-TR-67 for the purchase of the
Bruker APEX CCD diffractometer and the Chemistry
Department of Tulane University for support of the X-ray
laboratory.
1
Yield: 550 mg (89%). Mp: 242-244 °C (dec). H NMR (400
MHz, DMSO-d6): δ 7.43-6.86 (m, Ph, 8H), 3.80 (s, OMe, 6H),
2.03 (s, CH3CN, 3H), 1.45 (s, tBu, 18H). 31P{1H} NMR (161 MHz,
DMSO-d6): δ 114.2 (br s). Anal. Calcd for C24H35N3O4P2Cu2I2:
C, 33.04; H, 4.04; N, 4.81. Found: C, 33.18; H, 3.97; N, 4.67.
Synthesis of [CuCl{(tBuNP(OC6H4OMe-o))2}2] (5). An aceto-
nitrile solution (10 mL) of CuCl (12 mg, 0.123 mmol) was
added to 1 (111 mg, 0.246 mmol) in 10 mL of acetonitrile with
stirring. After 4 h of stirring, the solution was concentrated to 8
mL under reduced pressure and stored at -30 °C for 2 days to
obtain the product as colorless crystals. Yield: 103 mg (83%).
Mp: 140-142 °C. 1H NMR (400 MHz, CDCl3): δ 7.37-6.83 (m,
Supporting Information Available: X-ray crystallographic data
in CIF format. This material is available free of charge via the
Internet at http://pubs.acs.org.
t
Ph, 16H), 3.82 (s, OMe, 12H), 1.43 (s, Bu, 36H). 31P{1H} NMR
(161 MHz, CDCl3): δ 134.9 (br s), 110.3 (br s). Anal. Calcd for
C44H64N4O8P4CuCl: C, 52.85; H, 6.45; N, 5.60. Found: C, 52.84;
H, 6.35; N, 5.91. MS (EI): m/z 963.43 (M - Cl).
IC060464J
Synthesis of [CuBr{(tBuNP(OC6H4OMe-o))2}2] (6). The syn-
thesis was the same as that for 5, except using CuBr (10 mg,
0.075 mmol) and 1 (67 mg, 0.15 mmol). Yield: 61 mg (79%).
Mp: 151-153 °C. 1H NMR (400 MHz, CDCl3): δ 7.37-6.83 (m,
(21) SMART, version 5.625; Bruker-AXS: Madison, WI, 2000.
(22) SAINT+, version 6.35A; Bruker-AXS: Madison, WI, 2002.
(23) Sheldrick, G. M. SADABS, version 2.05; University of Go¨ttingen:
Go¨ttingen, Germany, 2002.
(24) (a) SHELXTL, version 6.10; Bruker-AXS: Madison, WI, 2000. (b)
Sheldrick, G. M. SHELXS97 and SHELXL97; University of Go¨ttin-
gen: Go¨ttingen, Germany, 1997.
t
Ph, 16H), 3.81 (s, OMe, 12H), 1.44 (s, Bu, 36H). 31P{1H} NMR
(161 MHz, CDCl3): δ 139.6 (br s), 108.6 (br s). Anal. Calcd for
Inorganic Chemistry, Vol. 45, No. 17, 2006 6683