Polymeric complexes of silver(I) with diphosphine ligands: Self-assembly of a puckered sheet network structure

Article abstract of DOI:10.1021/ja0113293

The syntheses and structures of polymeric silver(I)-diphosphine complexes are reported, in which the silver(I) center is surrounded by 1, 2, or 3 phosphorus atoms. When rigid diphosphine ligands are used in combination with weakly coordinating anions, linear polymers are obtained that contain both diphosphine and anion bridges. However, with excess of a diphosphine with a long, flexible, spacer group, a remarkable puckered sheet structure, comprised of fused giant 54-membered rings, is obtained that is a coordination polymer analogue of laminated materials such as micas and clays. The polymeric chain and sheet structures may be considered to be formed by ring-opening polymerization of cyclic precursors.

Full text of DOI:10.1021/ja0113293

Published on Web 03/21/2002
Polymeric Complexes of Silver(I) with Diphosphine Ligands:
Self-Assembly of a Puckered Sheet Network Structure
Marie-Claude Brandys and Richard J. Puddephatt*
Contribution from the Department of Chemistry, UniVersity of Western Ontario,
London, Canada N6A 5B7
Received May 31, 2001
Abstract: The syntheses and structures of polymeric silver(I)-diphosphine complexes are reported, in
which the silver(I) center is surrounded by 1, 2, or 3 phosphorus atoms. When rigid diphosphine ligands
are used in combination with weakly coordinating anions, linear polymers are obtained that contain both
diphosphine and anion bridges. However, with excess of a diphosphine with a long, flexible, spacer group,
a remarkable puckered sheet structure, comprised of fused giant 54-membered rings, is obtained that is
a coordination polymer analogue of laminated materials such as micas and clays. The polymeric chain
and sheet structures may be considered to be formed by ring-opening polymerization of cyclic precursors.
Chart 1. The Honeycomb and Puckered Network Structures
Introduction
The self-assembly of polymers and nanostructures through
coordination chemistry has become a very topical field, since
the metal centers can act as nodes to control the self-assembly
process, often using bidentate spacer ligands as connecting units,
and the metals offer a natural functional group in the resulting
material. For polymer synthesis, metals having two (linear), three
(T-shaped or trigonal planar), or four (tetrahedral) or more
available sites tend to give 1D, 2D, or 3D polymers, respec-
tively.1 In designing these structures it is often useful to compare
the overall architecture to that of a known material. For example,
two-dimensional networks based on trigonal planar coordination
have been characterized and they exist as planar sheets, such
as the honeycomb or chickenwire structure that is a structural
analogue of graphite [Chart 1a].1 Another possible 2D structure
is the puckered sheet network, which exists in the elemental
structures of arsenic, antimony, and bismuth, as well as in some
metal silicides and related materials, and which is based on
trigonal pyramidal nodes [Chart 1b].2 Related but more complex
structures exist with edge bridging groups E and capping groups
X, based on tetrahedral nodes as shown in Chart 1c, and these
are important in many laminated materials such as micas and
clays that contain [Si2O5]2- repeating units [Chart 1c, M ) Si,
E ) X ) O].2 This article reports the simple self-assembly of
a puckered sheet material [Chart 1c, M ) Ag, E ) bridging
diphosphine, X ) trifluoroacetate] prepared through the coor-
dination chemistry approach. It also reports two one-dimensional
polymers that demonstrate the versatility of the combination of
silver(I) and diphosphine units in forming different types of
coordination polymer. Previous related work on silver(I)
coordination polymers has concentrated on the use of nitrogen-
donor ligands,3 but the use of phosphine ligands either alone or
in combination with oxygen- and nitrogen-donor ligands has
much promise in the synthesis of robust polymers and
networks.4-6 Silver(I) complexes have potential as emissive or
medicinally active materials.4,7 In some cases, the polymers
reported here may be considered to be formed by ring-opening
polymerization of cyclic precursors.
(3) (a) Munakata, M.; Wu, L. P.; Kuroda-Sowa, T. AdV. Inorg. Chem. 1999,
46, 173. (b) Blake, A. J.; Champness, N. R.; Hubberstey, P.; Li, W.-S.;
Schroder, M.; Withersby, M. A. Coord. Chem. ReV. 1999, 183, 117.
(4) (a) Caruso, F.; Camalli, M.; Rimml, H.; Venanzi, L. M. Inorg. Chem. 1995,
34, 673. (b) Kitagawa, S.; Kondo, M.; Kawata, S.; Wada, S.; Maekawa,
M.; Munataka, M. Inorg. Chem. 1995, 34, 1455. (c) Crabtree, S. P.;
Batsanov, A. S.; Howard, J. A. K.; Kilner, M. Polyhedron 1998, 17, 367.
(d) Berners-Price, S. J.; Bowen, R. J.; Galettis, P.; Healy, P. C.; McKeage,
M. J. Coord. Chem. ReV. 1999, 186, 823. (e) Affandi, D.; Berner-Price, S.
J.; Effendy; Harvey, P. J.; Healy, P. C.; Ruch, B. E.; White, A. H. J. Chem.
Soc., Dalton, Trans. 1997, 1411. (f) Che, C.-M.; Tse, M.-C.; Chan, M. C.
W.; Cheung, K.-K.; Phillips, D. L.; Leung, K.-H. J. Am. Chem. Soc. 2000,
122, 2464. (g) Bessel, C. A.; Aggarwal, P.; Marschilok, A. C.; Takeuchi,
K. J. Chem. ReV. 2001, 101, 1031. (h) Cassel, A. Acta Crystallogr. 1976,
B32, 2521. (i) Hor, T. S. A.; Neo, S. P.; Tan, C. S.; Mak, T. C. W.; Leung,
K.-P.; Wang, R.-J. Inorg. Chem. 1992, 31, 4510.
(1) (a) Zaworotko, M. J. J. Chem. Soc., Chem. Commun. 2001, 1. (b) Blake,
A. J.; Champness, N. R.; Hubberstey, P.; Li, W.-S.; Withersby, M. A.;
Schro¨der, M. Coord. Chem. ReV., 1999, 183, 117. (c) Batten, S. R.; Robson,
R. Angew. Chem., Int. Ed. Engl. 1998, 37, 1460. (d) Brandys, M.-C.;
Jennings, M. C.; Puddephatt, R. J J. Chem. Soc., Dalton Trans. 2000, 4601.
(2) Wells, A. F. Structural Inorganic Chemistry; Oxford University Press:
Oxford, 1975.
(5) Lozano, E.; Nieuwenhuyzen, M.; James, S. L. Chem. Eur. J. 2001, 7, 2644.
(6) Brandys, M.-C.; Puddephatt, R. J. Chem. Commun. 2001, 1508.
(7) (a) Kitagawa, S.; Munataka, M.; Tanimura, T. Inorg. Chem. 1992, 31, 1714.
(b) Munataka, M.; Kuroda-Sowa, T.; Maekawa, M.; Nakamura, M.;
Akiyama, S.-I.; Kitagawa, S. Inorg. Chem., 1994, 33, 1284. (c) Otieno, T.;
Rettig, S. J.; Thompson, R. C.; Trotter, J. Inorg. Chem. 1993, 32, 1607.
(d) Janiak, C.; Uehlin, L.; Wu, H. P.; Klufers, P.; Piotrowski, H.;
9
3946
J. AM. CHEM. SOC. 2002, 124, 3946-3950
10.1021/ja0113293 CCC: $22.00 © 2002 American Chemical Society

Polymeric Complexes of Ag(I) with Diphosphine Ligands
A R T I C L E S
Chart 2
Silver(I) can have a coordination number ranging from 2 to
4, and diphosphine ligands may bind in several different ways
(chelate vs bridge, syn Vs anti conformation when bridging)
depending on the length and rigidity of the spacer group, so
there is potential for many structural types in silver diphosphine
complexes.4 Many of the binuclear structures shown in Chart 2
(in this chart, the group PP is a diphosphine with unspecified
spacer group) are known. For example, the complex [Ag2(µ-
O2CCF3)2(µ-bis(diphenylphosphino)methane)] adopts the struc-
ture A.4f Structure C is found with the diphosphine ligand 1,2-
bis[(diphenylphosphino)methyl]benzene,4a while structure D is
found with the ligands 1,5-bis(diphenylphosphino)pentane and
1,6-bis(diphenylphosphino)hexane.4b,h Structures F and G are
known with the diphosphines 1,1′-bis(diphenylphosphino)-
ferrocene or bis(diphenylphosphino)acetylene.4i,5 However, the
isomeric polymeric or network structures B, E, and H are now
reported for the first time.4-6 The polymeric complexes are very
sparingly soluble, probably with fragmentation to smaller units.
Characterization therefore relies primarily on X-ray structure
determinations though spectroscopic and analytical data were
also obtained.
Figure 1. The structure of complex 1: (a) an individual disilver unit, with
thermal ellipsoids for phenyl group carbons omitted for clarity and (b) the
“dimer of dimers” structure, with phenyl groups and fluorine atoms omitted
for clarity. Thermal ellipsoids are shown at 30% probability.
Figure 2. A view of the polymeric chain structure of complex 2. Thermal
ellipsoids are not shown for phenyl carbons, and fluorine atoms of the
disordered trifluoroacetate ligands are omitted for clarity. Thermal ellipsoids
are shown at 30% probability.
Table 1. Selected Bond Lengths (Å) and Angles (deg) for
Complex 1
Results and Discussion
Complexes with AgPO2 or AgPO3 Coordination and the
Effect of the Diphosphine Ligand. The complexes [Ag2(µ-
O2CCF3)2(µ- cis-Ph2PCHdCHPPh2)] [1; structure A, Chart 2,
PP ) cis-Ph2PCHdCHPPh2, X ) CF3CO2] and [{Ag2(µ-O2-
CCF3)2(µ- trans-Ph2PCHdCHPPh2)}x] [2; structure B, Chart
2, PP ) trans-Ph2PCHdCHPPh2, X ) CF3CO2] were prepared
simply from the corresponding silver salt and diphosphine ligand
in the required ratio, and were isolated as colorless crystalline
solids. The structures are shown in Figures 1 and 2, while
selected bond lengths and angles are listed in Tables 1 and 2.
The structure of complex 1 (Figure 1) is that of a dimer of
binuclear silver(I) complexes of structure A (Chart 2). Formation
of each binuclear unit occurs by coordination of the silver atoms
by one phosphorus atom from the bridging diphosphine ligand
and by two oxygen atoms from the bridging bidentate trifluo-
roacetate groups as shown in Figure 1a. The distance Ag(1)-
Ag(2) ) 2.8757(3) Å between the two silver centers is indicative
Ag(1)-O(4)
2.479(2)
Ag(1)-O(4A) 2.411(2)
P(1)-Ag(1)-O(1)
P(1)-Ag(1)-O(4A)
P(1)-Ag(1)-O(4)
P(2)-Ag(2)-O(2)
P(2)-Ag(2)-O(3)
O(4A)-Ag(1)-O(4)
O(1)-Ag(1)-O(4)
O(3)-Ag(2)-O(2)
142.29(7)
119.83(6)
125.39(5)
115.52(7)
134.71(6)
79.58(6)
Ag(1)-O(1)
Ag(2)-O(2)
Ag(2)-O(3)
Ag(1)-P(1)
Ag(2)-P(2)
Ag(1)-Ag(2)
2.258(2)
2.329(2)
2.242(2)
2.3597(7)
2.3587(7)
2.8757(3)
81.72(8)
109.68(9)
Ag(1A)-O(4)-Ag(1) 100.42(6)
of a weak attractive interaction. The structure of this unit is
similar to that of [Ag2)(µ-O2CCF3)2(µ-dppm)], dppm ) Ph2-
PCH2PPh2, which has a similar value of Ag‚‚‚Ag ) 2.8892(9)
Å.4f The diphosphine bridges the pair of silver(I) centers and
adopts the syn conformation, and this is a key feature that allows
formation of the binuclear unit (Figure 1a). The “dimer of
dimers” is formed by additional bridging of the oxygen atom
O(4) of a trifluoroacetate ligand to a silver atom Ag(1A) of a
neighboring dimer and the complementary bridging Ag(1)-
O(4A), as shown in Figure 1b. The overall result is that Ag(1)
has AgPO3 coordination (distorted tetrahedral) while Ag(2) has
AgPO2 coordination (distorted trigonal planar). The distances
Scharmann, T. G. J. Chem. Soc., Dalton 1999, 3121. (e) Janiak, C.;
Scharmann, T. G.; Albrecht, P.; Marlow, F.; MacDonald, R. J. Am. Chem.
Soc. 1996, 118, 6307. (f) Wu, H. P.; Janiak, C.; Rheinwald, G.; Lang, H.
J. Chem. Soc., Dalton 1999, 183.
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A R T I C L E S
Brandys and Puddephatt
Table 3. Selected Bond Lengths (Å) and Angles (deg) for
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
Complex 2
Complex 3
Ag(1)-O(1)
Ag(2)-O(3)
Ag(2)-O(1)
Ag(1)-O(3)
Ag(1)-P(1)
Ag(2)-P(2)
2.292(10)
2.281(9)
2.433(10)
2.402(9)
2.362(4)
2.364(4)
P(1)-Ag(1)-O(1)
P(1)-Ag(1)-O(3)
P(2)-Ag(2)-O(1)
P(2)-Ag(2)-O(3)
O(1)-Ag(1)-O(3)
O(1)-Ag(2)-O(3)
Ag(1)-O(1)-Ag(2)
Ag(1)-O(3)-Ag(2)
149.4(3)
137.8(2)
137.8(2)
150.1(2)
72.2(3)
71.8(3)
107.3(4)
108.7(4)
Ag(1)-O(1)
Ag(1)-O(1A)
Ag(1)-P(2)
Ag(1)-P(3)
2.323(3)
2.443(3)
2.458(1)
2.462(1)
O(1)-Ag(1)-P(2)
O(1)-Ag(1)-P(3)
O(1A)-Ag(1)-P(2)
O(1A)-Ag(1)-P(3)
O(1)-Ag(1)-O(1A)
Ag(1)-O(1)-Ag(1A)
P(2)-Ag(1)-P(3)
123.42(9)
123.18(9)
118.68(9)
109.93(8)
68.1(1)
111.9(1)
107.32(4)
Figure 3. A view of the polymeric chain structure of complex 3. Thermal
ellipsoids are not shown for phenyl carbons for clarity. Thermal ellipsoids
are shown at 30% probability.
Ag(1)-O(4) and Ag(1)-O(4A) are 2.479(2) and 2.411(2) Å,
respectively; they are longer than the other Ag-O bonds present
in this structure (see Table 1). The Ag-P bond distances are
Ag(1)-P(1) ) 2.3597(7) Å and Ag(2)-P(2) ) 2.3587(7) Å,
which are not significantly different despite the different
coordination numbers of Ag(1) and Ag(2).
As seen in Figure 2, the complex [{Ag2(µ-O2CCF3)2(µ-trans-
Ph2PCHdCHPPh2)}x], 2, forms a polymeric chain structure in
the solid state. The major difference in comparison to 1 is that
the diphosphine ligand trans-Ph2PCHdCHPPh2 adopts the anti
conformation in bridging between silver(I) centers and this
favors polymer rather than ring formation. The chains are
continued through bridging of the trifluoroacetate ligands, which
bridge as µ-η1 ligands (Figure 2) rather than the µ-η2 bridging
mode observed in 1 (Figure 1). All silver(I) centers in complex
2 are three-coordinate with distorted trigonal planar AgPO2
coordination. Clearly, the different structures of 1 and 2 arise
as a result of the different geometries and conformations of the
diphosphine ligands cis- or trans-Ph2PCHdCHPPh2, respec-
tively. Complex 2 is the first known example of structure B
(Chart 2).
It is noteworthy in the structures of both 1 and 2 that the
trifluoroacetate anion bridges between silver atoms either
through one or two oxygen donors, rather than chelating through
both oxygen donors. An important factor in this respect is the
relatively low coordination numbers of 3 and 4 involved, with
natural trigonal or tetrahedral bond angles, respectively, such
that the small OAgO bond angle in a chelate complex is
relatively unfavorable compared to metal centers having higher
coordination numbers.
Figure 4. Views of the structure of complex 4: (a) a single giant ring and
(b) the puckered sheet network structure. The phenyl substituents on
phosphorus and the fluorine atoms of the trifluoroacetate ligands are omitted
for clarity. Thermal ellipsoids are shown at 30% probability.
Table 4. Selected Bond Lengths (Å) and Angles (deg) for
Complex 4
Ag(1)-O(1)
Ag(1)-P(1)
Ag(1)-P(2)
Ag(1)-P(3)
2.464(2)
P(1)-Ag(1)-O(1)
P(2)-Ag(1)-O(1)
P(3)-Ag(1)-O(1)
P(2)-Ag(1)-P(1)
P(2)-Ag(1)-P(3)
P(3)-Ag(1)-P(1)
84.19(5)
111.91(5)
108.50(5)
124.83(2)
116.55(2)
105.77(2)
2.5089(7)
2.4371(7)
2.4813(7)
(I) center is four-coordinate with distorted tetrahedral AgP2O2
coordination. The diphosphines bridge between silver(I) centers
to give 10-membered Ag2(PCCP)2 rings that are connected by
bridging nitrate groups. The nitrate groups bridge through a
single oxygen donor, similar to the trifluoroacetate bridges in
the polymeric complex 2 (Figure 2). In both 2 and 3, the
alternate structures A and C or D, respectively (Chart 2), are
disfavored by the geometrical constraints of the diphosphine
ligands and so the self-assembly naturally gives the observed
polymeric forms B or E. Attempts were made to crystallize the
corresponding trifluoroacetate complex so as to study the anion
effect on the self-assembly, but without success. The silver(I)
centers in 3 are more sterically hindered than in 2, and it is
possible that the low steric effects of the nitrate anion are
important in allowing the structure to form.
A Polymeric Complex with AgP2O2 Coordination. The
complex [{Ag2(µ-NO3)2(µ-Ph2PCtCPPh2)2}x], 3, was prepared
simply by reaction of silver nitrate with the diphosphine ligand
in the required ratio. The structure of complex 3 is shown in
Figure 3 and selected bond parameters are given in Table 3. It
is the first known example of the polymeric structure E (Chart
2, X ) NO3, PP ) Ph2PCtCPPh2). In complex 3 each silver-
A Puckered Sheet Structure with AgP3O Coordination.
The reaction of silver(I) trifluoroacetate with an excess of the
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Polymeric Complexes of Ag(I) with Diphosphine Ligands
A R T I C L E S
Table 5. Crystal Data and Structure Refinements for Complexes 1, 2, 3, and 4
1
2
3‚2CH Cl2
4
C47H48AgF3O2P3
2
formula
fw
C30H22Ag2F6O4P2
838.16
C30H22Ag2F6O4P2
838.16
C54H44Ag2Cl4N2O6P4
1298.33
902.63
T (K)
200(2)
200(2)
150(2)
150(2)
cryst syst
space group
a (Å)
b (Å)
c (Å)
monoclinic
P2(1)/n
13.2240(3)
10.7446(3)
21.7756(6)
90
93.8560(10)
90
3087.02(14)
4
triclinic
P1
triclinic
P1h
monoclinic
P2(1)/n
12.4871(3)
18.5027(4)
19.7472(3)
90
107.3960(10)
90
4353.81(16)
4
8.4040(4)
10.1275(6)
10.4449(6)
114.040(2)
97.505(3)
104.681(3)
757.35(7)
1
10.5392(7)
11.7291(7)
12.1754(10)
110.701(3)
98.828(3)
96.685(4)
1367.30(17)
1
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
µ (mm-1
F(000)
)
1.443
1648
1.471
412
1.079
652
0.623
1860
θ range (deg)
no. of reflcns coll../ind.
Goof
2.58-30.02
16808/8986
0.926
2.60 to 27.49
4882/4882
1.095
2.85 to 27.54
9233/6274
1.105
2.57 to 30.05
23962/12725
0.734
R [I > 2σ(I)]
R1 ) 0.0354
wR2 ) 0.0823
R1 ) 0.0651
wR2 ) 0.0893
R1 ) 0.0295
wR2 ) 0.0698
R1 ) 0.0.369
wR2 ) 0.0724
R1 ) 0.0525
wR2 ) 0.1486
R1 ) 0.0722
wR2 ) 0.1578
R1 ) 0.0414
wR2 ) 0.1124
R1 ) 0.0770
wR2 ) 0.1306
R (all data)
flexible, long-chain diphosphine ligand 1,6-bis(diphenylphos-
phino)hexane gave the complex [{Ag(O2CCF3)(µ-Ph2P(CH2)6-
PPh2)1.5}x] [4; structure H, Chart 2, PP ) Ph2P(CH2)6PPh2, X
) CF3CO2], whose remarkable structure is shown in Figure 4,
with selected bond parameters in Table 4.
complex [{Au(µ-Ph2P(CH2)4PPh2)1.5}x]x+ forms a honeycomb
sheet structure (Chart 1) containing fused 42-membered [Au6-
(µ-PP)6] rings; since gold(I) prefers a lower coordination number
compared to silver(I), the anions are not coordinated in this
case.9 There appear to be no significant intersheet secondary
bonding interactions in complex 4 and so it might be expected
to easily accommodate intercalated guests, but none are present
in the solid-state structure.
In complex 4 each silver(I) center is four-coordinate with
distorted tetrahedral AgP3O coordination. A given silver atom
is connected to three others by bridging diphosphine ligands,
and the trifluoroacetate ligands are terminally coordinated
(Figure 4a). The presence of monodentate trifluoroacetate,
compared to the bridging forms seen in complexes 1 and 2, is
expected since the silver(I) centers have the 18-electron con-
figuration with AgP3O coordination. All silver atoms are
crystallographically equivalent and each is a node in three giant
54-membered [AgPC6P]6 rings, one of which is illustrated in
Figure 4a. The angles around the Ag center are distorted from
tetrahedral geometry, with the P-Ag-P angles ranging from
105.77(2) to 124.83(2)°. Each giant ring in complex 4 adopts
an extended chair conformation, with each ring edge trans-fused
to an adjacent ring. The resulting extended structure, illustrated
in Figure 4b, is a clear example of the puckered sheet structure
[Chart 1c, M ) Ag, X ) CF3CO2, E ) diphosphine]. It is likely
that the preference for the anti conformation of a diphosphine
ligand Ph2P(CH2)nPPh2 when n is an even integer is a factor in
favoring the extended structure rather than the isomeric forms
such as F and G (Chart 2), though such flexible long-chain
ligands are also capable of adopting the syn conformation.1,4
The puckered sheet structure has been observed in copper(I)
chemistry in the complex cation [{Cu(µ-NC4H4N)1.5(MeCN)}x]x+,
with rigid bridging pyrazine ligands, and there is one precedent
in silver(I) chemistry using tripyrazolylborate ligands.3,7 Another
analogue is the complex [{Ag2(µ-NO3)2(µ-phenazine)}x], which
has a 3-dimensional network structure comprised of sheets
connected by nitrate bridges. Within each sheet, there are
distorted hexagons of silver(I) atoms with edges bridged by
either phenazine or nitrate ions.3,8 In gold chemistry a related
In summary, it has been possible to design polymers
incorporating silver(I) centers with AgP, AgP2, and AgP3
coordination arising from bridging diphosphine ligands by
considering the rigidity, bite distance, and conformational
preference of the diphosphine ligands. The use of the “node +
spacer” concept in the synthesis of a silver(I) coordination
polymer having the important puckered sheet structure is
reported. Finally, it is noted that the polymer or network
structures B, E, and H (Chart 2) are related to the binuclear
structures A, C, D, F, and G by formal ring-opening polym-
erization. Conversion of A to B or D to E requires conversion
of intradimer to interdimer Ag2(µ-X) links and is expected to
be favorable if the relatively close Ag‚‚‚Ag separation that is
necessary in structures A and D causes strain in the Ag2(µ-PP)
unit. The structure of complex 1 (Figure 1b) is particularly
interesting since it contains both types of Ag2(µ-X) links
(Figures 1a and 2), and so could be regarded as an intermediate
between the binuclear and polymeric forms. It also highlights
the importance of the anion in the self-assembly process.
Conversion of C to E or F to H requires opening of chelating
Ag(PP) to bridging Ag2(µ-PP) units and will be favored when
the chelate is strained, while conversion of G to H requires
double ring-opening polymerization and will be favored when
the diphosphine has a preference for the anti rather than syn
conformation.5,9 Self-assembly is a complex process and it is
difficult to eliminate other factors that might play a role in
determining selectivity. The only case in which other bonding
forces might be significant is in complex 4, for which intralayer
phenyl-phenyl face-to-face π-stacking is present (centroids
separated by less than 4 Å) and may serve to stabilize the large
(8) (a) Munataka, M.; Kitagawa, S.; Ujimaru, N.; Nakamura, M.; Maekawa,
M.; Matsuda, H. Inorg. Chem. 1993, 32, 826. (b) Carlucci, L.; Ciani, G.;
Proserpio, D. M.; Sironi, A. J. Am. Chem. Soc. 1995, 117, 4562.
(9) Brandys, M.-C.; Puddephatt, R. J. J. Am. Chem. Soc. 2001, 123, 4839.
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A R T I C L E S
Brandys and Puddephatt
solution layered with pentane. NMR in CD2Cl2/CD3OD: δ1(H) 7.39
[m, broad, 40H, Ph]. δ31(P) (CP-MAS solid state) -21.5 (broad).
[{Ag(O2CCF3)(Ph2P(CH2)6PPh2)1.5}x], 4. 1,6-Bis(diphenylphosphi-
no)hexane (0.211 g, 0.464 mmol) was added to a solution of silver
trifluoroacetate (0.68 g, 0.310 mmol) in THF (10 mL). After the mixture
was stirred for 2 h, a white precipitate of was collected by filtration,
and washed with THF, ether, and pentane. Yield: 0.20 g (70%). Crystals
were obtained from a CH2Cl2 solution layered with pentane. NMR in
CD2Cl2/CD3OD: δ1(H) 7.34 [m, 12H, o-H Ph]; 7.18 [m, 18H, m,p-H
Ph]; 2.16 [m, 6H, CH2-P]; 1.33 [m, 12H, CH2CH2-P]. δ31(P) (CP-
MAS solid state) -1.5 (broad).
X-ray Structure Determinations. Data were collected on a Nonius
Kappa-CCD diffractometer with use of COLLECT (Nonius, 1998)
software. The unit cell parameters were calculated and refined from
the full data set. Crystal cell refinement and data reduction was carried
out with the Nonius DENZO package. The data were scaled by using
SCALEPACK (Nonius, 1998) and no other absorption corrections were
applied. The SHELXTL 5.1 (Sheldrick, G. M., Madison, WI) program
package was used to solve the structure by direct methods, followed
by refinements with successive difference Fouriers. The hydrogen atoms
were calculated geometrically, riding on their respective carbon atoms.
For complex 2, all non-hydrogen atoms were refined anisotropically
except for C5 and the F atoms, which were restrained so that their Uij
component approximates isotropic behavior (ISOR). The phenyl rings
were constrained to be regular hexagons (AFIX 66). There was disorder
in the positions of the fluorine atoms of the CF3 group and two sets of
fluorine atoms were refined to 71/29% occupation. For complexes 1,
3, and 4, all non-hydrogen atoms were refined with anisotropic thermal
parameters.
rings. No significant interchain or interlayer secondary bonding
interactions were identified. The principles outlined above can
clearly be applied to the design and synthesis of other coordina-
tion polymers and networks with the convenient diphosphine
ligands used in the present work. Many silver(I) phosphine
complexes show emissive properties in the solid state1,3,4 but
those described above do not, and this may be a result of the
polymeric structures.
Experimental Section
Solution 1H and 31P NMR spectra were recorded on a Varian Inova
400 MHz spectrometer and chemical shifts are reported relative to TMS
or 85% H3PO4(aq). 31P CP-MAS solid-state NMR spectra were collected
on a Varian Infinity Plus WB 9.4 T spectrometer, with a 31P operating
frequency of 161.72 MHz, and using a ramp and tppm decoupling at
a spinning rate of 15 kHz, with zirconium oxide rotors. 31P CP-MAS
chemical shifts were referenced to NH4H2PO4 at 0.81 ppm (wrt H3PO4).
Syntheses were carried out at room temperature and crystals were grown
at 4 °C.
[{Ag2(µ-O2CCF3)2(µ-cis-Ph2PCHdCHPPh2)}2], 1. A mixture of
cis-1,2-bis(diphenylphosphino)ethylene (0.071 g, 0.179 mmol) and
silver trifluoroacetate (0.079 g, 0.358 mmol) in THF (10 mL) was
allowed to stir for 2 h. Pentane was then added dropwise, to yield the
product as a white precipitate. Yield: 0.11 g, 73%. Crystals were
obtained from a CH2Cl2 solution layered with pentane. NMR in CD2-
Cl2: δ1(H) 7.56 [m, 10H, Ph]; 7.44 [m, 10H, Ph]; 7.06 [t, Jobs(PH) )
18 Hz, 2H, CHdCH). δ31(P) 1.9 (broad).
[{(Ag2(µ-O2CCF3)2(µ-trans-Ph2PCHdCHPPh2)}x], 2. 2 was pre-
pared similarly from trans-1,2-bis(diphenylphosphino)ethylene (0.060
g, 0.151 mmol) with silver trifluoroacetate (0.067 g, 0.303 mmol) in
THF (10 mL). Yield: 0.10 g (79%). Crystals were obtained from a
CH2Cl2 solution layered with pentane. NMR in CD2Cl2/CD3OD: δ1(H)
7.40 [m, 20H, Ph]; 7.02 [t, Jobs(PH) ) 18 Hz, 2H, CHdCH]. δ(31P)
(CP-MAS solid state) 8.5 [broad].
[{Ag2(µ-NO3)2(µ-Ph2PCtCPPh2)2}x], 3. This complex was pre-
pared in a similar fashion from bis(diphenylphosphino)acetylene (0.143
g, 0.363 mmol) and silver nitrate (0.063 g, 0.371 mmol) in THF (10
mL). Yield: 0.18 g (86%). Crystals were obtained from a CH2Cl2
Acknowledgment. We thank the NSERC (Canada) for
financial support to R.J.P. and for a scholarship to M.-C.B.,
and Dr. M. C. Jennings for X-ray data collection. R.J.P. thanks
the Government of Canada for a Canada Research Chair.
Supporting Information Available: Tables of X-ray data for
complexes 1-4 (PDF). This material is available free of charge
via the Internet at http://pubs.acs.org.
JA0113293
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3950 J. AM. CHEM. SOC. VOL. 124, NO. 15, 2002