Copper(I) and silver(I) tertiary phosphines complexes: Synthesis, X-ray structures and spectroscopic characterization

Article abstract of DOI:10.1016/j.ica.2010.04.031

Six new complexes, [ Cu₄I₄(PPh₂Cy ) ₄]2H₂O (1), [Cul(PPhCy₂)₂] (2), [CuCl(PPhCy₂J₂] (3), and [CuBr(PPh₃) ₃]. CH₃CN (4), [Ag(PPhCy₂)₂(NO ₃)] (5), [Ag(PCy₃)(NO₃)]₂ (6) [where Ph - phenyl, Cy - cyclohexyl], have been synthesized and structurally characterized by X-ray diffraction, IR absorption spectra and NMR spectroscopic studies (except complex 4). The X-ray diffraction analysis of complex (1), pseudo polymorph of complex [Cu₄I₄(PPh₂Cy) ₄], reveals a stella quadrangula structure. The four corners of the cube are occupied by copper(I) atoms and four I atoms are present at the alternative corners of the cube, further more the copper(I) atoms are coordinated to a monodentate tertiary phosphine. Complexes (2) and (3) are isostructural with trigonal planar geometry around the copper(I) atom. The crystal structure of complex (4) is a pseudo polymorph of complex [CuBr(PPh ₃)₃] and the geometrical environment around the copper(I) centre is distorted tetrahedral. In the Ag^I complexes (5) and (6), the central metal atoms have pseudo tetrahedral and trigonal planar geometry, respectively. Spectroscopic and microanalysis results are consistent with the single crystal X-ray diffraction studies.

Full text of DOI:10.1016/j.ica.2010.04.031

Inorganica Chimica Acta 363 (2010) 2567–2573
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Copper(I) and silver(I) tertiary phosphines complexes: Synthesis, X-ray structures
and spectroscopic characterization
*
Muhammad Altaf , Helen Stoeckli-Evans
Institute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland
a r t i c l e i n f o
a b s t r a c t
Article history:
Six new complexes, [Cu4I4(PPh2Cy)4]Á2H2O (1), [CuI(PPhCy2)2] (2), [CuCl(PPhCy2)2] (3), and [CuBr(PPh3)3]Á
CH3CN (4), [Ag(PPhCy2)2(NO3)] (5), [Ag(PCy3)(NO3)]2 (6) [where Ph = phenyl, Cy = cyclohexyl], have been
synthesized and structurally characterized by X-ray diffraction, IR absorption spectra and NMR spectro-
scopic studies (except complex 4). The X-ray diffraction analysis of complex (1), pseudo polymorph of
complex [Cu4I4(PPh2Cy)4], reveals a stella quadrangula structure. The four corners of the cube are occu-
pied by copper(I) atoms and four I atoms are present at the alternative corners of the cube, further more
the copper(I) atoms are coordinated to a monodentate tertiary phosphine. Complexes (2) and (3) are iso-
structural with trigonal planar geometry around the copper(I) atom. The crystal structure of complex (4)
is a pseudo polymorph of complex [CuBr(PPh3)3] and the geometrical environment around the copper(I)
centre is distorted tetrahedral. In the AgI complexes (5) and (6), the central metal atoms have pseudo tet-
rahedral and trigonal planar geometry, respectively. Spectroscopic and microanalysis results are consis-
tent with the single crystal X-ray diffraction studies.
Received 24 October 2009
Received in revised form 6 April 2010
Accepted 18 April 2010
Available online 28 April 2010
Keywords:
Tertiary phosphines
Copper(I) and silver(I) complexes
NMR spectroscopy
X-ray structure
Phosphorous donor ligand
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
compounds with stoichiometry 1:2 and 1:3 are monomers and
dimers with tetrahedral and trigonal planar geometries, respec-
Our interest in the CuI and AgI compounds with monodentate
tertiary phosphine ligands; is to explore the structural chemistry
of these complexes and their mixed ligand multi-dimensional
complexes of versatile architectures. Reaction of coin metal(I) salts
with monodentate tertiary phosphine bases yielded an array of
two, three, and four coordinated complexes with diverse structural
properties that are determined by the specific choice of the phos-
phine ligand and to a lesser extent, by the choice of counter ions
[1]. Neutral phosphine and amine ligands form mono- or multi-nu-
clear complexes with copper(I) and copper(II) salts, in which the
coordination number ranges from two to four [2–10]. The greatest
range of structural types has been found for the case of tertiary
phosphines, of which the most extensively studied is triphenyl
phosphine and to a lesser extent tricyclohexyl phosphine [11–16].
The geometry around the copper(I) atom in complexes with ter-
tiary phosphine ligands depends on the stoichiometric ratio of the
metal salt and ligand used, as well as the solvent of crystallization.
Thus for a compound of 1:1 stoichiometry monomer, dimer and
tetramer complexes are possible with general formulae of
[MX(PR3)], [M2X2(PR3)2] and [M4X4(PR3)4] (where M = Ag and Cu.
R = phenyl, alkyl, aryl or cyclohexyl groups) [1,17–20]. Whereas,
the compounds with stoichiometry 1:1.5 are dimers [15,16], and
tively, around the metal centre [11,22–24]. The complexes of gen-
eral formula [M4X4(PR3)4] (X = Cl, Br or I) have pseudo cubane-like
structures [10,25,26]. These types of structures can be described as
two interpenetrating tetrahedra of four metals (M) and four triply
bridging halides (anions) situated on alternative corners of a dis-
torted cube with each metal atom being further coordinated to
one terminal monodentate ligand [17]. Frequently a non-system-
atic deviation of the cubane core from the idealized tetrahedral
geometry is observed for cubane-like metal clusters [27–29].
Tertiary phosphine complexes of silver(I) of the type [AgXLn],
where L = tertiary phosphine; n = 1–4; X = coordinating or non-
coordinating anion, were first prepared as early as 1937 [30–38].
The reaction of silver(I) salts with monodentate tertiary phosphines
in a 1:2 stoichiometric ratio generally results in the formation of
either monomeric [AgX(PR3)2]/[Ag(PR3)2]ÁX [39–51], or dimeric
complexes [AgX(PR3)2]2 [51–54], depending on the donor proper-
ties of the phosphine ligand, the bulkiness of this ligand, and the do-
nor properties of the anion. These complexes show a diversity of
structural types and several reviews on this topic have been pub-
lished [31–38]. The metal centre in the majority of the neutral
[AgX(PR3)2] and [AgX(PR3)2]2 complexes are predominantly four
coordinate, with the anion acting as either a bi-dentate chelating li-
gand or as a bridging ligand. Two or three coordination have been
found only in circumstances where the anion is a weak donor or
the substituents on the phosphine ligand are bulky [43,46–51].
* Corresponding author. Tel.: +41 32 718 24 00; fax: +41 32 718 25 11.
E-mail address: muhammad.altaf@unine.ch (M. Altaf).
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.04.031

2568
M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
Although a large number of copper(I) complexes with mono-
20 ml of MeOH/H2O (3:1), 10 ml of MeCN was added to the above
reaction mixture to get a transparent solution. The clear solution
obtained was filtered to avoid any impurity and kept at room tem-
perature for slow evaporation. After five days plate-like crystals
were obtained. The crystalline product was collected by filtration
and air dried. During this reaction Cu(II) is reduced to Cu(I) in
the presence of strong reducing agents like tertiary phosphines. A
suitable crystal was chosen for X-ray diffraction analysis (Yield:
78%). Anal. Calc. for C36H54ClCuP2: C, 66.70; H, 8.34. Found: C,
dentate tertiary phosphine have been reported [1,11–15], such
complexes with neutral phosphines are consider as good starting
materials for the crystal synthesis of metal organic frameworks
of pre-designed architectures and properties [6–8,14,55,56]. Here-
in, we report the synthesis and structural characterization of six
metal(I) complexes with tertiary phosphines. The X-ray structures,
IR absorption spectra and NMR spectral data are also described
herein.
66.62; H, 8.28%. IR (m
, cmÀ1): 3413m, 3053w, 2929vs, 2837s,
1613vw, 1471m, 1410vs, 1343m, 1259m, 1165m, 1008m, 873m,
755vs, 499s. 1H NMR (CD2Cl2; ppm): 1.2–2.4 (m, 22H, cyclohexyl
protons), and 7.1–7.4 (m, 5H, phenyl protons). 13C NMR (CD2Cl2;
ppm): 26.2–32.4 (cyclohexyl carbons), and 127.9–134.5 (phenyl
carbons). 31P NMR (CD2Cl2; ppm): 6.3 (s, sharp).
2. Experimental
2.1. Material and physical measurements
All chemical and solvents were of analytical grade (purchased
from Aldrich and ACROS) and were used without further purifica-
tion. Microanalysis was done by Mr. D. Mooser (Ecole d’ingénieurs
de Fribourg, Filière de chimie). The IR spectra were recorded as KBr
pellets on a PerkinElmer Spectrum One FTIR instrument. 1H, 13C,
and 31P NMR spectra were recorded on a Bruker AMX 400 MHz
using CD2Cl2 as solvent. TMS was used as the internal standard.
We have experienced for the synthesis of the silver(I) complexes
in the presence of phosphines that a discoloration or the formation
of silver particles is very slow and takes a number of weeks. Hence,
these reactions were carried out under normal laboratory
conditions.
2.5. Synthesis of [CuBr(PPh3)3].CH3CN (4)
CuBr2 (0.224 g, 0.1 mmol) and PPh3 (0.525 g, 0.2 mmol) in 15 ml
CH2Cl2 were dissolved by continuous heating and mechanical stir-
ring at 30 °C for 20 min. The resultant reaction mixture was further
treated with thiosemicarbazide (0.091 g, 0.1 mmol) in 10 ml of
MeCN/MeOH (1:1) solution. The reaction mixture was stirred for
20 min again. The resultant clear solution was filtered to avoid
any impurity and kept undisturbed at room temperature for slow
evaporation. During this reaction process, according to expecta-
tions, Cu(II) was reduced to Cu(I) in the presence of the strong
reducing agent, triphenyl phosphine. After seven days colourless
block crystals of unexpected product were obtained. A suitable
crystal was chosen for X-ray diffraction analysis. (Yield: 70%). Anal.
Calc. for C56H48NBrCuP3: C, 69.18; H, 4.94; N, 1.44. Found: C, 69.13;
2.2. Synthesis of [Cu4I4(PPh2Cy)4].2H2O (1)
For the synthesis of complex (1) CuI (0.19 g, 0.1 mmol) and
PPh2Cy (0.268 g, 0.1 mmol) were dissolved in 20 ml of CH2Cl2/
MeOH (2:1). The reaction mixture was stirred for 10 min at room
temperature. The clear solution obtained was filtered to avoid
any impurity and kept at room temperature for slow evaporation.
After two days colourless block crystals were obtained. A suitable
crystal was chosen for X-ray diffraction analysis (Yield: 75%). Anal.
Calc. for C72H88Cu4I4P4O2: C, 46.18; H, 4.70. Found: C, 46.07; H,
H, 4.98; N, 1.47%. IR (m
, cmÀ1): 3413m, 3049s, 2223w, 1616w,
1584m, 1478vs, 1308m, 1154s, 997m, 741vs, 693s, 507vs. No
NMR spectroscopic characterization was done due to the poor sol-
ubility of the complex in the available solvents.
2.6. Synthesis of [Ag(PPhCy2)2(NO3)] (5)
4.68%. IR
(m,
cmÀ1): 3523b, 3414m, 3051w, 2924vs, 2847s,
To a solution of AgNO3 (0.017 g, 0.1 mmol) in distilled water
(5 mL) was added dicyclohexylphenyl phosphine (0.055 g,
0.2 mmol) in acetone/acetonitrile (1:1) (20 mL). The reaction mix-
ture was stirred for 2 h at rt. The clear solution obtained was fil-
tered and left at rt for slow evaporation. After a few days
colourless plate-like crystals were obtained (Yield: 68%). Anal. Calc.
for C36H54AgNO3P2: C, 60.11; H, 7.51; N, 1.95. Found: C, 60.43; H,
1618vw, 1480m, 1432vs, 1331m, 1271m, 1169m, 1000m, 887m,
742vs, 527s. 1H NMR (CD2Cl2; ppm): 1.6–2.0, 2.5 (m, 11H, cyclo-
hexyl protons), and 7.3–7.7 (m, 10H, phenyl protons). 13C NMR
(CD2Cl2; ppm): 26.0–36.0 (cyclohexyl carbons), and 128.2–134.0
(phenyl carbons). 31P NMR (CD2Cl2; ppm): À9.3 (s, sharp).
(m,
cmÀ1): 3551m, 3478s, 3412s, 3075w,
2.3. Synthesis of [CuI(PPhCy2)2] (2)
7.62; N, 2.28%. IR
3052w, 2928vs, 2858s, 1638m, 1617s, 1447vs, 1277m, 1175s,
1003s, 847m, 658vs, 533m. 1H NMR (CD2Cl2-d2; ppm): 1–2.6 (m,
22H, cyclohexyl protons), and 7–8 (m, 5H, phenyl protons). 13C
NMR (CD2Cl2-d2; ppm): 26.1–32.8 (cyclohexyl carbons), and
128.6–135.0 (phenyl carbons). 31P NMR (CD2Cl2-d2; ppm): 24.1–
27.1 (d. one peak for phosphorous atom of tertiary phosphine).
CuI (0.19 g, 0.1 mmol) and PPhCy2 (0.55 g, 0.2 mmol) in 20 ml of
MeCN were dissolved by continuous stirring with moderate heat-
ing. A small amount of CHCl3 was added as solvent of crystalliza-
tion. The colourless clear solution obtained was filtered to avoid
any impurity and kept undisturbed for crystallization. After three
days colourless plate-like crystals were obtained. A suitable crystal
was chosen for X-ray diffraction studies (Yield: 67%). Anal. Calc. for
2.7. Synthesis of [Ag(PCy3)(NO3)]2 (6)
C
36H54CuIP2: C, 58.44; H, 7.30. Found: C, 58.35; H, 7.28%. IR (m,
cmÀ1): 3417m, 3045w, 2922vs, 2842s, 1619vw, 1483m, 1412vs,
1323m, 1275m, 1173m, 997m, 883m, 752vs, 526s. 1H NMR
(CD2Cl2; ppm): 1.2–2.4 (m, 22H, cyclohexyl protons), and 7.3–7.6
(m, 5H, phenyl protons). 13C NMR (CD2Cl2; ppm): 26.1–32.5 (cyclo-
hexyl carbons), and 127.9–134.7 (phenyl carbons). 31P NMR
(CD2Cl2; ppm): 6.3 (s, sharp).
To a solution of AgNO3 (0.017 g, 0.1 mmol) in distilled water
(5 mL) was added tricyclohexyl phosphine (0.028 g, 0.1 mmol) in
acetone (15 mL). After the reaction mixture was stirred for 1 h at
rt. The colourless solution obtained was filtered to avoid any impu-
rity and left undisturbed for slow evaporation. After three days col-
ourless block-like crystals were obtained (Yield: 78%). Anal. Calc.
for C36H66Ag2N2O6P2: C, 47.96; H, 7.32; N, 3.10. Found: C, 48.67;
2.4. Synthesis of [CuCl(PPhCy2)2] (3)
H, 7.46; N, 3.13%. IR (m
, cmÀ1): 3551m, 3412m, 2918s, 2828s,
1638m, 1616s, 1446vs, 1297m, 1174s, 1005s, 839vs, 557s. 1H
NMR (CD2Cl2-d2; ppm): 1.2–2.0 (m, 22H, cyclohexyl protons). 13C
NMR (CD2Cl2-d2; ppm): 26.2–32.3 (cyclohexyl carbons). 31P NMR
CuCl2 (0.135 g, 0.1 mmol) and PPhCy2 (0.55 g, 0.2 mmol) were
dissolved by gentle heating and continuous stirring for 20 min in

M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
2569
(CD2Cl2-d2; ppm): 42.3 (d. single peak for phosphorous atom of tri-
cyclohexyl phosphine).
2.8. X-ray crystallography
The intensity data were collected at 173 K on either, a one circle
(/ scans) [57], or a two circle (
Diffraction System, using Mo K
x
a
and / scans) [58] Stoe Image Plate
graphite monochromated radia-
tion. The structures were solved by Direct methods using the pro-
gram SHELXS-97 [59]. The refinement and all further calculations
were carried out using SHELXL-97 [59]. The H-atoms were either lo-
cated from Fourier difference maps and freely refined or included
in calculated positions and treated as riding atoms using SHELXL de-
fault parameters. The non-H atoms were refined anisotropically,
using weighted full-matrix least-squares on F2. Empirical or mul-
ti-scan absorption corrections were applied using the REFdelABS
and MULscanABS routines in [60]. For compound 1 a region of dif-
fuse electron density was treated with the SQUEEZE routine in PLA-
TON [60]. The electron density was estimated to be equivalent to 4
water molecules of crystallization per unit cell, or two water mol-
Fig. 2. View of the crystal structure of complex 2, with a partial atom labelling
scheme and the displacement ellipsoids drawn at the 30% probability level
[H-atoms have been omitted for clarity].
ꢀ
ecules per molecule of complex (space group P1, Z = 2). Figs. 1–6
were drawn using the program Mercury [61]. A summary of crystal
data and refinement details for compounds 1–6 are given in Table
1, and selected bond lengths and angles are listed in Table 2.
3. Results and discussion
3.1. Structural descriptions
3.1.1. [Cu4I4(PPh2Cy)4]Á2H2O (1)
The crystal structure of [Cu4I4(PPh2Cy)4]Á2H2O (1) has been
determined at low temperature and the molecular structure is gi-
ven in Fig. 1. Selected bond lengths and angles are tabulated in
Table 2. The asymmetric unit of complex 1 consists of one mole-
cule of [Cu4I4(PPh2Cy)4] and two water molecules of crystalliza-
tion. It is
[Cu4I4(PPh2Cy)4], which crystallized in the monoclinic space group
2/c [21], compared to 1 which crystallises in the triclinic space
a pseudo polymorph of the non-hydrated form,
C
Fig. 3. View of the molecular structure of complex 3 with selected atom labelling
scheme and the displacement ellipsoids drawn at the 30% probability level [H-
atoms have been omitted for clarity].
ꢀ
group P1 (Table 1). It is also isostructural with the molecular
complexes of general formula [Cu4X4(PPh3)4] [27–29].
The central unit of complex 1 can be described as a strongly dis-
torted cube in which four corners are occupied by four I atoms and
on alternative corners of the cube there are four CuI atoms, which
are coordinated with a monodentate tertiary phosphine as a termi-
nal ligand. The molecular structure of the complex adopts a cub-
ane-like configuration with two interpenetrating tetrahedra of
complex; the copper and iodine atoms form a markedly distorted
cube (as shown in Fig. 1), each copper atom being further coordi-
nated to a diphenylcyclohexyl phosphine ligand.
The most notable structural feature of complex 1 is that both
the bonding and nonbonding distances of the Cu4I4 core deviate
greatly from the idealized cubic tetrahedral geometry expected
from bonding considerations. In this distorted cubane-like struc-
ture the average CuÁÁÁCu distance is ca. 2.966 Å; the IÁÁÁI interatomic
distances vary from ca. 4.18 to 4.30 Å. The Cu–I distances range
from 2.6402(8) to 2.7252(7) Å. These inter-cubane distances indi-
cate that there is no metal–metal interaction (d10–d10 interaction)
in the solid state structure of 1. Interatomic distances found in
complex 1 are comparable with those in similar reported struc-
tures [10,21,27–29].
Fig. 1. View of the molecular structure of complex 1, with selected atom labelling
scheme and the displacement ellipsoids drawn at the 30% probability level
[H-atoms have been omitted for clarity].

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M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
show considerable deviation from the ideal trigonal planar angle
of 120°.
3.1.3. [CuCl(PPhCy2)2] (3)
The molecular structure of complex 3 is isostructural and iso-
morphous to complex 2. A perspective view of the molecular struc-
ture of complex 3 is shown in Fig. 3, with selective atom labelling
Scheme. The geometrical environment around the copper(I) centre
is distorted trigonal planar. The Cu–Cl bond distance 2.241(2) Å is
shorter than Cu–I bond distance found in complex 2 and this differ-
ence is attributed to the different atomic sizes of chlorine and io-
dine atoms coordinated with same type of metal centre. The Cu–
P bond distances 2.250(2) and 2.257(2) Å; are longer than in com-
plex 2. The P–Cu–Cl bond angles are 113.33(9)° and 116.51(8)°,
whereas the P–Cu–P bond angle is 130.10(9)°. Again these bond
angles values show considerable deviation from the ideal trigonal
planar angle of 120°.
3.1.4. [CuBr(PPh3)3]ÁCH3CN (4)
A view of molecular structure of complex 4 is shown in Fig. 4,
with selected atom labelling Scheme. The molecular structure of
Fig. 4. A view of the molecular structure of complex 4ÁCH3CN, with partial atom
labelling and displacement ellipsoids drawn at the 30% probability level [H-atoms
have been omitted for clarity].
the complex is
a
pseudo polymorph of the complexes
[CuBr(PPh3)3], [CuBr(PPh3)3]ÁTHF, and [CuBr(PPh3)3]Á(CH3)2CO
[22,62], which were all measured at room temperature. The crys-
tallographic environment around the copper(I) atom is distorted
tetrahedral, as found in the other polymorphic forms. The asym-
metric unit contains one acetonitrile molecule of crystallization.
The solvent molecule does not show any coordination with the me-
tal centre and is well separated. This observation is similar to that
in the other pseudo-polymorphic forms of the complex. The cop-
per(I) centre is coordinated with three monodentate triphenyl
phosphine ligand molecules and one bromine atom. The Cu–P bond
distances range from 2.305(1) to 2.314(1) Å, and the Cu–Br bond
distance is 2.483(1) Å. The Cu–P bond distances are slightly shorter
than those found in the polymorphic forms, where these distances
vary from 2.329 to 2.369 Å. The Cu–Br bond distance is longer than
that found in [CuBr(PPh3)3]ÁTHF [62], that is 2.439 Å, but shorter
than that found in [CuBr(PPh3)3] and [CuBr(PPh3)3]Á(CH3)2CO
[22], that is, 2.503 and 2.506 Å, respectively. These differences
may in part be due to the fact that the X-ray diffraction data for
complex 4 were measured at 173 K, while for the pseudo poly-
morphs the data were in general measured at 293 K. The bond an-
gles values around the copper(I) atom vary from 99.05(3)° to
Fig. 5. A view of the molecular structure of compound 5, with displacement
ellipsoids drawn at the 30% probability level [H-atoms have been omitted for
clarity].
120.08(3)°, which indicates
a distorted tetrahedral geometry
around the copper(I) atom. The deviation from ideal tetrahedral
geometry around the central metal atom is similar to that found
in its polymorphic forms.
The evidence concerning the large deformation of the Cu4I4 core
is given by the Cu–I–Cu angles, which range from 67.19(3)° to
73.72(2)°, and the I–Cu–I angles, which vary from 100.90(2)° to
111.30(3)°. These bond angles describe well the deviation from
ideal cubane-like structures.
3.1.5. [Ag(PPhCy2)2(NO3)] (5)
Complex 5 crystallized in the chiral monoclinic space group P21.
The geometrical environment around the silver(I) atom can be con-
sidered to be pseudo trigonal planar, with the silver(I) atom coor-
dinated with two phosphorous atoms of the monodentate tertiary
phosphine and one oxygen atom of the nitrate counter ion (Fig. 5).
The Ag–P1 and Ag–P2 bond distances are 2.4043(8) and
2.4260(8) Å, respectively, and the Ag–O1 and Ag–O3 bond dis-
tances are 2.606(4) and 2.687(3) Å, respectively. The rather long
Ag–O3 bond distance indicates the presence of a weak Ag–O coor-
dination bond, hence the metal centre in this neutral complex can
be considered to be four coordinate, with the anion acting as a bi-
dentate chelating ligand. The two phosphine ligands are present in
a partially eclipsed conformation with O–Ag–P bond angles of
3.1.2. [CuI(PPhCy2)2] (2)
A perspective view of the molecular structure of complex 2 is
shown in Fig. 2, with selective atom labelling Scheme. The crystal
structure of complex 2 is isostructural to the complexes with gen-
eral formula [CuX(PCy3)2] (X = Cl, Br, I) [1]. The geometry around
the copper(I) centre is trigonal planar. The average Cu–P distance
is 2.2395(8) Å, this is shorter than that found in other CuI com-
plexes [1]. Whereas, the Cu–I distance 2.536(4) Å is also shorter
than that found in complex [CuI(PCy3)2] [1]. The bond angles
around the copper(I) centre are 133.04(3)° for P–Cu–P and
111.55(3)° and 115.37(2)° for I–Cu–P. These bond angles values
89.74(9)° and 115.46(9)°, and
a P1–Ag1–P2 bond angle of
154.25(3)°. These bond angles around the silver(I) atom show con-
siderable deviation from the ideal trigonal planar angle of 120°.

M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
2571
Fig. 6. A view of the molecular structure of complex with displacement ellipsoids drawn at the 30% probability level [H-atoms have been omitted for clarity].
Table 1
Summary of crystal data and structure refinement details for compounds 1–6.
1.2H2O
72H84Cu4I4P4
1871.06
2
3
4ÁCH3CN
C54H45BrCuP3
971.31
5
6
Empirical formula
Formula weight
Crystal size (mm)
Wavelength (Å)
Temperature (K)
Crystal symmetry
Space group
a (Å)
C
C36H54CuIP2
739.17
C36H54ClCuP2
647.72
C36H54AgNO3P2
718.61
C36H66Ag2N2O6P2
900.59
0.38 Â 0.34 Â 0.30 0.45 Â 0.45 Â 0.40 0.30 Â 0.19 Â 0.08 0.30 Â 0.19 Â 0.11 0.37 Â 0.37 Â 0.16 0.50 Â 0.50 Â 0.29
0.71073
173
0.71073
173
Monoclinic
P21/n
10.4500(3)
23.4853(10)
14.6356(5)
90
9.586(3)
90
3541.7(2)
4
1.386
1.601
1528
1.65–29.55
68 504
9593(0.0734)
8361
1.186
0.0438
0.099
0.71073
173
Monoclinic
P21/n
10.2513(9)
24.433(2)
13.9602(12)
90
99.929(10)
90
3444.2(5)
4
1.249
0.828
1384
0.71073
173
0.71073
173
Monoclinic
P21
10.9551(7)
13.7042(6)
12.2536(8)
90
107.158(5)
90
1757.77(18)
2
1.358
0.699
756
0.71073
173
Triclinic
Triclinic
Triclinic
ꢀ
ꢀ
ꢀ
P1
P1
P1
13.6424(13)
14.1754(14)
21.583(2)
101.305(12)
96.666(12)
111.047(11)
3739.7(6)
2
1.662
2.9
1848
2.07–26.04
29 409
11.5329(10)
13.0973(11)
15.7012(14)
88.859(10)
83.677(10)
84.956(10)
2348.0(4)
2
1.374
1.457
1000
1.90–25.90
18 563
9.1676(7)
9.1338(7)
13.3139(10)
91.077(6)
97.359(6)
116.098(6)
989.39(13)
1
1.512
1.115
468
1.55–29.72
14 354
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dc (Mg mÀ3
)
l
(Mo K
F(0 0 0)
h Limits (°)
a
) (mmÀ1
)
2.1–22.80
25 811
6761(0.2323)
1925
1.73–29.43
27 426
9005(0.0669)
7682
1.022
0.0374
Measured reflections
Unique reflections (Rint
Observed reflections
)
13 628(0.0459)
8896
0.824
0.0327
0.0684
8580(0.0606)
4743
0.76
0.0319
0.0516
5332(0.0229)
5057
1.084
0.0234
0.0593
Goodness-of-fit (GOF) on F2
0.71
R1(F),a [I > 2
r
(I)]
r
0.0661
0.1506
0.585, À1.108
wR2 (F2),b [I > 2
(I)]
0.0844
0.513, À0.975
Largest differences in peak and hole
0.956, À0.922
0.813, À0.749
0.466, À0.521
0.409, À0.860
(e ÅÀ3
)
P
P
a
R1
=
||Fo| À |Fc||/ |Fo|.
P
P
wR2 = [ w(F2o À Fc2)2/ wFo4]1/2
.
b
3.1.6. [Ag(PCy3)2(NO3)]2 (6)
accommodated by dislocation of the two Cy3PAgO fragments with-
in the [PAg(O)2AgP] plane.
Compound 6 is a centrosymmetric binuclear complex and its
molecular structure is illustrated in Fig. 6. The metal centres are
three coÀordinate with distorted trigonal planar geometry, and with
the NO3 anion acting as an asymmetric monodentate bridging li-
gand. The [PAg(O)2AgP] unit is planar within experimental error;
the oxygen atoms bonded to the silver atoms are in-plane, while
atoms N1/O2/O3 are out-of-plane. The two phosphine ligand mol-
ecules coordinated to the silver(I) atom are staggered and adopt a
disposition of opposite chirality. The P–C7 bond rotates out of the
[PAg(O)2AgP] plane and this rotation results in an unsymmetrical
interaction between the oxygen atom of the nitrate anion and
the neighbouring cyclohexyl group hydrogen atoms, such that
bond Ag–O1 is shorter than bond Ag–O1i, and bond angle P–Ag–
O1 is larger than angle P–Ag–O1i (Table 2). This distortion is
In compound 7 the Ag–P bond length is 2.3374(4) Å and the
Ag–O bond distances are 2.2475(13) and 2.4210(15) Å. The
O1–Ag1–P1 and O1i–Ag1–P1 bond angles are 155.78(4)° and
133.59(3)°, respectively. The O1–Ag–O1i bond angle is 70.55(5)°
and the bridging Ag1–O1–Ag1i angle is 109.45(6)°, with a AgÁÁÁAg
distance of 3.8126(3) Å; shows no metal–metal interaction.
In the crystal structures of the copper(I) complexes, 1–4, there
are no classical hydrogen bonding interactions. Only in complexes
2, 3 and 4 are there C–HÁÁÁhalogen interactions. In complex 1 the
halogens are embedded in a cavity surrounded by the phosphine
substituents. In complexes 2 and 4 two-dimensional sheet-like
networks are formed, while in complex 3 a one-dimensional chain
is formed. In the silver(I) complexes, 5 and 6, there are a number of

2572
M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
Table 2
characteristic bands for aromatic and non-aromatic hydrogen
2900–3100 cmÀ1 for all complexes. For complexes 1 and 4, several
stretching bands are also observed in the spectra.
Selected bond distances (Å) and bond angles (°) for complex 1–6.
Bond lengths (Å)
Bond angles (°)
In the 1H and 13C NMR spectra of complexes 1–3 no classical
variation has been observed. The pattern of cyclohexyl and phenyl
resonances is similar to those reported for a silver(1) and gold(I)
complex [63,64,39].
1
I1–Cu2
I1–Cu3
I2–Cu1
I2–Cu2
I2–Cu4
I3–Cu2
I3–Cu3
I3–Cu4
I4–Cu1
I4–Cu3
I4–Cu4
Cu1–P1
Cu2–P2
Cu3–P3
Cu4–P4
2.6750(8)
2.7135(7)
2.6631(8)
2.6646(8)
2.7251(7)
2.7006(7)
2.7125(8)
2.7064(8)
2.7182(7)
2.6399(8)
2.6977(8)
2.2413(15)
2.2439(14)
2.2416(15)
2.2510(16)
Cu1–I1–Cu2
Cu1–I1–Cu3
Cu2–I1–Cu3
Cu1–I2–Cu2
Cu1–I2–Cu4
Cu2–I2–Cu4
Cu2–I3–Cu3
Cu2–I3–Cu4
Cu3–I3–Cu4
Cu1–I4–Cu3
Cu1–I4–Cu4
Cu3–I4–Cu4
I1–Cu1–I2
I1–Cu1–I4
I1–Cu1–P1
I2–Cu1–I4
I2–Cu1–P1
I4–Cu1–P1
I1–Cu2–I2
I1–Cu2–I3
I1–Cu2–P2
I2–Cu2–I3
I2–Cu2–P2
I3–Cu2–P2
I1–Cu3–I3
I1–Cu3–I4
I1–Cu3–P3
I3–Cu3–I4
I3–Cu3–P3
I4–Cu3–P3
I2–Cu4–I3
I2–Cu4–I4
I2–Cu4–P4
I3–Cu4–I4
I3–Cu4–P4
I4–Cu4–P4
67.19(3)
71.63(2)
73.73(2)
67.67(3)
73.41(2)
71.64(2)
73.35(2)
71.38(2)
70.36(3)
In 31P NMR of compound 1, a sharp singlet was observed for
diphenylcyclohexyl phosphine at À9.3 ppm, which is 3 ppm down
field compared to the free phosphine (ꢀÀ6.12 ppm). In 31P NMR of
compound 2 and 3, sharp single peaks were observed at 6.3 ppm
for dicyclohexylphenyl phosphine, those are about ꢀ37 ppm
downfield compared to free phosphine (ꢀ43.1 ppm). This type of
behaviour of 31P NMR is well documented [39]. The 31P NMR spec-
tra of complexes of silver(I) with phosphorous-donor ligands may
show splitting due to 1J(P–Ag) coupling. In the 31P NMR spectra of
complex 5 two well defined doublet peaks were observed at 24.1
and 27.1 ppm, about 23, and 26 ppm, respectively, downfield com-
pared to the uncomplexed dicyclohexylphenyl phosphine
(ꢀ1 ppm). In the 31P NMR of compound 6, the resonance for the
coordinated tricyclohexyl phosphine appear as an intense doublet
peak at 42.3 ppm, about 34 ppm, downfield compared to the
uncomplexed tricyclohexyl phosphine (ꢀ8 ppm). Silver(I) com-
plexes with (1:2, and 1:1 stoichiometric ratio) show well resolved
pairs of doublets, the resolution of signals for 1:2 and 1:1 species is
due to 1J(P–Ag) coupling (1J(P–Ag) = 1200 and 1J(P–Ag) = 1040 MHz
respectively for compounds 5 and 6). The 31P NMR spectral results
are in agreement with the previously reported silver(I) phosphine
complexes [22,30–54,63,65].
72.25(2)
72.98(2)
71.58(3)
111.04(3)
104.49(3)
113.35(5)
103.21(3)
115.60(5)
107.96(4)
111.32(3)
102.20(3)
117.53(5)
106.57(3)
108.86(4)
109.68(4)
100.90(3)
105.89(3)
114.37(5)
108.63(3)
112.07(5)
113.98(4)
104.72(3)
102.11(3)
114.21(4)
107.13(3)
112.27(5)
115.35(4)
4. Conclusions
X-ay diffraction studies of complexes 1–6 suggest that the geo-
metrical environment around the CuI and AgI centres is highly
dependent on the stoichiometric ratio of the reactants, the type
of phosphines used (cyclohexyl or phenyl groups), the counter
ions, and the solvent of crystallization. The use of cyclohexyl type
phosphines resulted in trigonal planar geometry around the metal
centre in compounds 2, 3, 5, and 6. For compounds 2 and 3 the sum
of the halide–Cu–P angles, while deviating from the standard angle
of 120°, add up to ca. 360°. In compound 5 the P–Ag–O and O–Ag–P
angles also add up to ca. 360° and in compound 6 the P–Ag–O and
O–Ag–O angles also add up to ca. 360°.
The use of phenyl type phosphines resulted in distorted tetrahe-
dral geometry in compounds 1 and 4. Here the sum of the halide–
Cu–P angles varies from ca. 336.0–341.8° in compound 1, while in
compound 4 this sum is only ca. 296.2°, indicating considerable
deformation of the copper(I) coordination sphere in both com-
pounds. In the 31P NMR spectra of compounds 1–3, 5–6, a down
field shift was observed. In the 31P NMR spectra of the silver(I)
complexes, 5 and 6, doublet peaks were observed due to 1J(P–Ag)
coupling, while for the copper(I) complexes only sharp singlet
peaks were present. The silver(I) and copper(I) complexes, 1–6,
were synthesized as precursors to explore the mixed ligand chem-
istry of coin metal(I) coordination compounds [66].
2
I1–Cu1
Cu1–P1
Cu1–P2
3
Cu1–Cl1
Cu1–P1
Cu1–P2
4
Br1–Cu1
Cu1–P1
Cu1–P2
Cu1–P3
2.5360(5)
2.2392(9)
2.2399(8)
I1–Cu1–P1
I1–Cu1–P2
P1–Cu1–P2
115.37(2)
111.55(3)
133.04(3)
2.241(2)
2.250(2)
2.257(2)
Cl1–Cu1–P1
Cl1–Cu1–P2
P1–Cu1–P2
113.33(9)
116.51(8)
130.10(9)
2.4826(5)
2.3112(9)
2.3045(9)
2.3138(10)
Br1–Cu1–P1
Br1–Cu1–P2
Br1–Cu1–P3
P1–Cu1–P2
P1–Cu1–P3
P2–Cu1–P3
105.53(3)
99.05(3)
101.63(3)
112.70(4)
114.56(4)
120.08(3)
5
Ag1–P1
Ag1–P2
Ag1–O1
Ag1–O3
6
2.4043(8)
2.4261(9)
2.606(4)
2.687(3)
P1–Ag1–P2
P1–Ag1–O1
P2–Ag1–O1
154.25(3)
115.47(9)
89.74(9)
Ag1ÁÁÁAg1i
Ag1–P1
Ag1–O1
Ag1–O1i
3.8126(3)
2.3374(4)
2.2475(13)
2.4210(15)
Ag1–O1–Ag1i
P1–Ag1–O1
P1–Ag1–O1i
O1–Ag1–O1i
109.45(6)
155.78(4)
133.60(3)
70.55(5)
Symmetry codes: (i) 2 À x, 1 À y, 1 À z.
Acknowledgements
C–HÁÁÁO interactions involving the nitrate O-atoms, which lead to
This work was partially supported by the Swiss National Sci-
ence Foundation.
the formation of one-dimensional chains.
3.2. 1H, 13C and 31P NMR Spectroscopic studies
Appendix A. Supplementary material
The IR spectra of compounds 1–6 have been recorded in the
range of 4000–450 cmÀ1 and are characterized by many absorption
bands of the coordinated tertiary phosphine ligands, apart from the
Supplementary crystallographic data of compounds 1–6 (CCDC
No. 739417–739419, 739421, 751728–751729) can be obtained

M. Altaf, H. Stoeckli-Evans / Inorganica Chimica Acta 363 (2010) 2567–2573
2573
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