1,1′-Bis(diphenyloxophosphoryl)ferrocene (dpopf) as ligand in silver(I) complexes. Crystal structure of [Ag(dpopf)(PPh3)2]ClO4

Article abstract of DOI:10.1016/S0020-1693(01)00379-6

The ligand 1,1′-bis(diphenyloxophosphoryl)ferrocene, dpopf, reacted with silver derivatives to afford mononuclear complexes, [Ag(OClO₃)(dpopf)] (1), [Ag(dpopf)₂]ClO₄, [Ag(dpopf)(PPh₃)]ClO₄, or the dinuclear complex, [{(Ag(PPh₃)})₂(dpopf)](ClO₄)₂. From 1, other three-, [Ag(dpopf)(SPPh₃)]ClO₄, and four-coordinated derivatives, [Ag(dpopf)(PPh₃)₂]ClO₄ (6) [Ag(dpopf)(L-L)]ClO₄ [L-L = bipy, (SPPh₂)₂CH₂] were obtained by substitution reactions. The crystal structure of 6 was solved and revealed the expected distorted tetrahedral coordination at silver, with a ligand bite angle of 96.10(13)°.

Full text of DOI:10.1016/S0020-1693(01)00379-6

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Inorganica Chimica Acta 316 (2001) 89–93
1,1%-Bis(diphenyloxophosphoryl)ferrocene (dpopf) as ligand in
silver(I) complexes. Crystal structure of [Ag(dpopf)(PPh3)2]ClO4
M. Concepcio´n Gimeno a, Peter G. Jones b, Antonio Laguna a,*, Cristina Sarroca a,
M. Dolores Villacampa a
a Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Uni6ersidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
b Institut fu¨r Anorganische und Analytische Chemie der Technischen Uni6ersita¨t, Postfach 3329, D-38023 Braunschweig, Germany
Received 2 January 2001; accepted 31 January 2001
Abstract
The ligand 1,1%-bis(diphenyloxophosphoryl)ferrocene, dpopf, reacted with silver derivatives to afford mononuclear complexes,
[Ag(OClO3)(dpopf)] (1), [Ag(dpopf)2]ClO4, [Ag(dpopf)(PPh3)]ClO4, or the dinuclear complex, [{Ag(PPh3)}2(dpopf)](ClO4)2. From
1, other three-, [Ag(dpopf)(SPPh3)]ClO4, and four-coordinated derivatives, [Ag(dpopf)(PPh3)2]ClO4 (6) [Ag(dpopf)(LꢀL)]ClO4
[LꢀL=bipy, (SPPh2)2CH2] were obtained by substitution reactions. The crystal structure of 6 was solved and revealed the
expected distorted tetrahedral coordination at silver, with a ligand bite angle of 96.10(13)°. © 2001 Elsevier Science B.V. All rights
reserved.
Keywords: Silver complexes; Ferrocene complexes; Diphosphine complexes; Crystal structures
1. Introduction
Here we report on the coordination chemistry of dpopf
with silver centres. Mono and dinuclear derivatives are
reported in which the oxygen donor ligand acts as
bridging or chelating ligand.
The chemistry of 1,1%-bis(diphenylphosphine)-
ferrocene (dppf) is currently receiving much attention
associated with its increasing applications [1]. It has a
strong bonding ability based on the two PPh2 groups
and it is a very flexible ligand that can modify its steric
bite in order to adapt to different geometric require-
ments of various metal centres. This has facilitated the
synthesis of a great number of mono or polynuclear
gold or silver derivatives with different geometries [2,3].
The oxidation of dppf to give bis(diphenyloxophos-
phoryl)ferrocene (dpopf), provides a new ligand with a
longer and more flexible backbone. The presence of
O-donor atoms could favour the coordination to cop-
per or silver centres, rather than gold. Some copper
complexes, such as [Cu(dppf)(dpopf)]BF4 [4], [Cu-
(dpopf)2](BF4)2, or [Cu(dpopf)2(EtOH)](BF4)2 [5], with
dpopf as chelating ligand, have been recently reported.
2. Results and discussion
The reaction of dpopf with AgClO4, in a molar ratio
1:1 or 2:1, gives the mononuclear complexes
[Ag(OClO3)(dpopf)] (1) or [Ag(dpopf)2]ClO4 (2), respec-
tively (See Scheme 1). They are yellow, air- and mois-
ture-stable solids and behave as 1:1 electrolytes in
acetone solution. Their IR spectrum shows, apart from
the bands arising from the dpopf ligand, those of the
perchlorate at 1097(vs, br), 1073(s), 919(w) and 623(m)
cm−1 (1) or 1096(vs, br) and 625(m) cm−1 (2). The
positive-ion LSI MS exhibits a peak corresponding to
the cation [Ag(dpopf)]+ or [Ag(dpopf)2]+ at m/z=693
1
(25%, 1) or 1279 (2%, 2), respectively. The H NMR
spectra show, apart from the multiplet from the phenyl
protons, two multiplets for the a and b protons of the
substituted cyclopentadienyl rings at approximately 4.2
and 4.6 ppm. The 31P{1H} NMR spectra at room
temperature show a singlet at 28.7 (1) or 34.4 ppm (2).
* Corresponding author. Tel.: +34-976-761185; fax: +34-976-
761187.
E-mail address: alaguna@posta.unizar.es (A. Laguna).
0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0020-1693(01)00379-6

90
M.C. Gimeno et al. / Inorganica Chimica Acta 316 (2001) 89–93
Scheme 1. (i) AgClO4; (ii) 1/2 AgClO4 (LꢀL=dpopf); (iii) [Ag(OClO3)(PPh3)] (L=PPh3); (iv) 2 [Ag(OClO3)(PPh3)]; (v) 2 PPh3; (vi) PPh3 or
SPPh3; (vii) bipy or (SPPh2)2CH2 or NaS2CNEt2.
The treatment of dpopf with [Ag(OClO3)(PPh3)], in
the molar ratio 1:1 or 1:2, gives the ionic mononuclear
two ligands (31.0 and 46.3 ppm (5) or 29.5 and 38.5
ppm (8)) or a singlet and a doublet of doublets for
complex 6 [−55°C, 36.6 and 11.4 ppm, J(PAg) 368.0
[Ag(dpopf)(PPh3)]ClO4
(3)
or
the
dinuclear
1
[{Ag(PPh3)}2(dpopf)](ClO4)2 (4) derivative as a yellow
solid. Complexes 3 and 4 behave as 1:1 or 2:1 elec-
trolytes, respectively. The positive-ion LSI MS exhibit a
peak corresponding to the cation [Ag(PPh3)(dpopf)]+
at m/z=957 (10%, 3; 22%, 4). The 31P{1H} NMR
spectrum of 3, at −55°, shows a broad singlet at 36.6
ppm (dpopf) and a poorly resolved doublet of doublets
(PPh3) at 11.4 ppm. Complex 4 shows, at room temper-
ature, a singlet at 38.4 (dpopf) and two doublets at 15.1
ppm [PPh3, J(PAg) 714.2 and 823.9 Hz].
Complex 1 reacts readily with further ligands. The
reaction with monodentate ligands leads to the three-
coordinate [Ag(dpopf)L]ClO4 [L=PPh3 (3), SPPh3 (5)]
or to the four-coordinate [Ag(dpopf)(PPh3)2]ClO4 (6)
complexes (Scheme 1). The reaction with bidentate
ligands leads to the four-coordinate [Ag(dpopf)(LꢀL))]-
ClO4 [LꢀL=bipy (7), (SPPh2)2CH2 (8)]. These are air-
and moisture-stable yellow solids that behave as 1:1
electrolytes in acetone solutions. The positive-ion LSI
MS show the cation molecular peak, [M−ClO4]+,
except for complex 7 [m/z=989 (5, 1%), 1219 (6, 1%),
1143 (8, 4%)]. The cation [Ag(dpopf)]+ is observed in
all the complexes (m/z=693). The vibration w(PꢁS)
appears in the IR spectra at 591(m) (5) or 568(m) cm−1
(8). The 31P{1H} NMR spectra present only a singlet
for complex 7 (32.4 ppm), two singlets for complexes 5
or 8, corresponding to the different phosphorus of the
and 318.7 Hz]. The H NMR spectra are in agreement
with the proposed structures (see Section 3). A complex
similar to 6, but with copper, [Cu(dpopf)(PPh3)2]NO3
(9), can be obtained by reaction of dpopf and
[Cu(NO3)(PPh3)2]. (31P{1H} NMR spectrum: two sin-
glets at 28.4 and−0.02 ppm).
The yellow, neutral complex [Ag(dpopf)(S2CNEt2)]
(10) can be obtained by reaction of complex 1 and
1
Na(S2CNEt2). The H NMR spectrum shows a multi-
plet at 4.37 (8H, C5H4), a quartet at 4.01 (4H, CH2),
and a triplet at 1.31 ppm (6H, CH3). The 31P{1H}
NMR spectrum presents only a singlet at 29.2 ppm.
The structure of complex 6 has been confirmed by an
X-ray crystal diffraction study. A selection of bond
Table 1
,
Selected bond lengths [A] and angles [°] for derivative 6
AgꢀO(2)
AgꢀO(1)
AgꢀP(2)
AgꢀP(1)
2.397(4)
2.410(4)
2.437(2)
2.443(2)
O(2)ꢀAgꢀO(1)
O(2)ꢀAgꢀP(2)
O(1)ꢀAgꢀP(2)
O(2)ꢀAgꢀP(1)
O(1)ꢀAgꢀP(1)
P(2)ꢀAgꢀP(1)
96.10(13)
97.13(10)
120.49(10)
115.68(11)
91.24(10)
131.93(6)

M.C. Gimeno et al. / Inorganica Chimica Acta 316 (2001) 89–93
91
tions (kept with Na2CO3), if no other solvent is stated;
chemical shifts are quoted relative to SiMe4 (external,
1H) and 85% H3PO4 (external, 31P).
The starting materials [Ag(OClO3)(PPh3)] [12], dpopf
[13] and (SPPh2)2CH2 [14] were prepared by published
procedures. Caution: perchlorate salts with organic
cations may be explosive.
3.1. Syntheses
3.1.1. [Ag(OClO3)(dpopf )] (1) or [Ag(dpopf )2]ClO4 (2)
To a solution of AgClO4 (0.021 g, 0.1 mmol) in
dichloromethane (20 cm3) was added dpopf (0.058 g,
0.1 mmol or 0.029 g, 0.05 mmol) and the mixture
stirred for 1 h. Concentration of the solution to approx-
imately 5 cm3 and addition of diethyl ether (10 cm3)
gave complex 1 or 2 as a yellow solid. Complex 1: Yield
89%. \M 121 ohm−1 cm2 mol−1. Elemental analysis:
Anal. Found: C, 51.2; H, 3.35. Calc. for
C34H28AgClFeO6P2: C, 51.45; H, 3.55%. Complex 2:
Yield 65%. \M 140 ohm−1 cm2 mol−1. Elemental
analysis: Anal. Found: C, 59.3; H, 3.9. Calc. for
C68H56AgClFe2O8P4: C, 59.2; H, 4.05%.
Fig. 1. The cation of compound 6 with the atom numbering scheme.
Hydrogen atoms have been omitted for clarity. Radii are arbitrary.
lengths and angles are collected in Table 1. Complex 6
crystallises with one molecule of dichloromethane. The
silver centre displays a highly distorted tetrahedral ge-
ometry; the angles around Ag range from 91.24(10)
[O(1)ꢀAgꢀP(1)] to 131.93(6) [P(2)ꢀAgꢀP(1)]. The
PꢀAgꢀP angle is appreciably larger than the ideal tetra-
hedral angle, possibly reflecting a tendency towards
strong linear bonding between silver(I) centres and
phosphine ligands. The metalꢀmetal distance Ag···Fe is
3.1.2. [Ag(dpopf )(PPh3)]ClO4 (3) or
[{Ag(PPh3)}2(dpopf )](ClO4)2 (4)
,
4.905 A. (Fig. 1)
To a solution of dpopf (0.059 g, 0.1 mmol) in
dichloromethane (20 cm3) was added [Ag(OClO3)-
(PPh3)] (0.047 g, 0.1 mmol or 0.094 g, 0.2 mmol) and
the mixture stirred for 90 min. Concentration of the
solution to approximately 5 cm3 and addition of diethyl
ether (10 cm3) gave complex 3 or 4 as a yellow solid.
,
The AgꢀP bond distances, 2.437(2) and 2.443(2) A,
are in line with those found in other tetrahedral silver
complexes such as [Ag(dppe)2]NO3 [6] (range 2.488(3)–
,
2.527(3) A), [Ag(phen){(PPh2)2C2B10H10}]ClO4 [7]
,
(2.463(2), 2.479(2) A) or [Ag{C5(CO2Me)5}(PPh3)2] [8]
,
(2.428(2), 2.414(2) A). The AgꢀO bond lengths
(2.397(4), 2.410(4) A) compare well with literature val-
ues for four-coordinated silver complexes [8–11].
Complex 3: Yield 80%. \M 130 ohm−1 cm2 mol−1
.
,
Elemental analysis: Anal. Found: C, 59.3; H, 3.85. Calc.
for C52H43AgClFeO6P3: C, 59.15; H, 4.05%. Complex
4: Yield 82%. \M 189 ohm−1 cm2 mol−1. Elemental
analysis: Anal. Found: C, 55.25; H, 3.75. Calc. for
C70H58Ag2Cl2FeO10P4: C, 55.15; H, 3.85%.
The perchlorate oxygens, which are well-defined (U
2
,
values approximately 0.07 A ), act as acceptors in
non-classical hydrogen bonds C199ꢀH199···O3 [H···O
,
,
2.24 A, CꢀH···O 156°], C43ꢀH43···O5 [2.48 A, 144°],
,
C73ꢀH73···O5 [2.44 A, 163°] and C14ꢀH14···O6 [2.40
3.1.3. [Ag(dpopf )L]ClO4 (L=PPh3, (3); SPPh3, (5)),
[Ag(dpopf )(PPh3)2]ClO4 (6) or [Ag(dpopf )(LꢀL)]ClO4
(LꢀL=bipy, (7); (SPPh2)2CH2, (8))
,
A, 142°].
To a solution of complex 1 (0.079 g, 0.1 mmol) in
dichloromethane (20 cm3) was added the neutral ligand
[PPh3, 0.026 g, 0.1 mmol or 0.052, 0.2 mmol; SPPh3,
0.029 g, 0.1 mmol; bipy, 0.011 g, 0.1 mmol or
(SPPh2)2CH2, 0.045 g, 0.1 mmol] and the mixture
stirred for 90 min. Concentration of the solution to
approximately 5 cm3 and addition of diethyl ether (10
cm3) gave complexes 3, or 5–8 as yellow solids. Com-
plex 3: Yield 60%. Complex 5: Yield 50%. \M 114
ohm−1 cm2 mol−1. Elemental analysis: Anal. Found:
C, 57.3; H, 3.85; S, 2.95. Calc. for C52H43AgClFeO6P3S:
C, 57.45; H, 4.05; S, 3.4%. Complex 6: Yield 70%. \M
138 ohm−1 cm2 mol−1. Elemental analysis: Anal.
Found: C, 63.7; H, 4.45. Calc. for C70H58AgClFeO6P4:
3. Experimental
Infrared spectra were recorded on a Perkin–Elmer
883 spectrophotometer, over the range 4000–200 cm−1
,
using Nujol mulls between polyethylene sheets. Con-
ductivities were measured in approximately 5×10−4
mol dm−3 solutions with a Philips 9509 conductimeter.
C, H, N and S analyses were carried out with a
Perkin–Elmer 2400 microanalyser. Mass spectra were
recorded on a VG Autospec, with the Liquid sec-
ondary-ion mass spectra (LSI MS) technique, using
nitrobenzyl alcohol as matrix. H and 31P{1H} NMR
spectra were recorded on a Varian UNITY 300, Bruker
ARX300 or GEMINI 2000 apparatus in CDCl3 solu-
1

92
M.C. Gimeno et al. / Inorganica Chimica Acta 316 (2001) 89–93
C, 63.8; H, 4.4%. Complex 7: Yield 82%. \M 122
ohm−1 cm2 mol−1. Elemental analysis: Anal. Found:
C, 55.4; H, 3.7; N, 3.45. Calc. for C44H36AgCl-
FeN2O6P2: C, 55.65; H, 3.8; N, 2.95%. Complex 8:
Yield 85%. \M 122 ohm−1 cm2 mol−1. Elemental
analysis: Anal. Found: C, 57.3; H, 4.1; S, 5.6. Calc. for
C59H50AgClFeO6P4S2: C, 57.05; H, 4.0; S, 5.15%.
(0.023 g, 0.1 mmol) and the mixture stirred for 3 h. The
suspension was filtered to remove the NaClO4 formed.
Concentration of the solution to approximately 5 cm3
and addition of diethyl ether (10 cm3) gave complex 10
as a yellow solid. Yield 75%. Elemental analysis: Anal.
Found: C, 56.1; H, 4.95; N, 1.7; S, 8.25. Calc. for
C39H38AgFeNO2P2S2: C, 55.6; H, 4.5; N, 1.65; S, 7.6%.
3.2. Crystallography
3.1.4. [Cu(dpopf )(PPh3)2]NO3 (9)
To a solution of dpopf (0.059 g, 0.1 mmol) in
dichloromethane (20 cm3) was added [Cu(NO3)(PPh3)2]
(0.065 g, 0.1 mmol) and the mixture stirred for 45 min.
Concentration of the solution to approximately 5 cm3
and addition of diethyl ether (10 cm3) gave complex 9
The crystal was mounted in inert oil on a glass fibre
and transferred to the cold gas stream of a Siemens P4
diffractometer equipped with an LT-2 low temperature
attachment. Data were collected using monochromated
as a yellow solid. Yield 69%. \M 26 ohm−1 cm2 mol−1
.
,
Mo Ka radiation (u=0.71073 A). Scan type ꢀ. An
absorption correction was based on c-scans. The struc-
ture was solved by the heavy-atom method, and refined
on F2 using the program SHELXL-93 [15]. All non-hy-
drogen atoms were refined anisotropically. Hydrogen
atoms were included using a riding model. Further
details are given in Table 2.
Elemental analysis: Anal. Found: C, 67.5; H, 4.4; N,
1.25. Calc. for C70H58CuFeNO5P4: C, 68.05; H, 4.75;
N, 1.15%.
3.1.5. [Ag(dpopf )(S2CNEt2)] (10)
To a solution of complex 1 (0.079 g, 0.1 mmol) in
dichloromethane (20 cm3) was added NaS2CNEt2
3.2.1. Special refinement details
A system of restraints to light-atom displacement-
factor components and local ring symmetry was used.
The absolute structure (polar axis direction) was deter-
mined by the method of Flack [16]; the x parameter
refined to −0.01(2).
Table 2
Details of data collection and structure refinement for complex 6
Compound
6·CH2Cl2
Chemical formula
C71H60AgCl3FeO6P4
Crystal habit
yellow tablet
0.6×0.6×0.2
orthorhombic
Pca21
34.026(4)
12.169(2)
15.674(3)
6490(2)
4
1.436
1403.14
2872
−100
50
4. Supplementary material
Crystal size (mm)
Crystal system
Space group
Complete crystallographic data (excluding structure
factors) have been deposited at the Cambridge Crystal-
lographic Data Centre under the number CCDC
155759. Copies can be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK. Fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk
,
a (A)
,
b (A)
,
c (A)
3
,
U (A )
Z
Dcalc (Mg m−3
M
)
F(000)
T (°C)
2qmax (°)
Acknowledgements
v(Mo Ka) (mm−1
)
0.800
0.740–0.849
10855
Transmission
We thank the Direccio´n General de Ensen˜anza Supe-
rior (No. PB97-1010-C02-01) and the Fonds der
Chemischen Industrie for financial support.
Number of reflections measured
Number of unique reflections
Rint
9524
0.0408
0.0439
0.0797
775
683
0.83
R
a(F, F\4|(F))
wR b(F2, all reflections)
Number of parameters
Number of restraints
References
c
S
−3
,
Maximum Dz (eA
)
0.53
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a R(F)=SꢀꢀFoꢀ−ꢀFcꢀꢀ/SꢀFoꢀ.
b wR(F2)=[S{w(Fo2−Fc2)2}/S{w(Fo2)2}]0.5
;
w
−1=|2(Fo2)+
(aP)2+bP, where P=[Fo2+2Fc2]/3 and a and b are constants ad-
justed by the program.
c S=[S{w(Fo2−Fc2)2}/(n−p)]0.5, where n is the number of data
points and p the number of parameters.

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