Synthesis and reactivity of the unsaturated trinuclear phosphanido complex [(C6F5)2Pt(μ-PPh2) 2Pt(μ-PPh2)2Pt(PPh3)]

Article abstract of DOI:10.1021/ic3021639

The reaction of [NBu₄][(C₆F₅) ₂Pt(μ-PPh₂)₂Pt(μ-PPh₂) ₂Pt(O,O-acac)] (48 VEC) with [HPPh₃][ClO₄] gives the 46 VEC unsaturated [(C₆F₅)₂Pt ¹(μ-PPh₂)₂Pt²(μ-PPh ₂)₂Pt³(PPh₃)](Pt²-Pt ³) (1), a trinuclear compound endowed with a Pt-Pt bond. This compound displays amphiphilic behavior and reacts easily with nucleophiles L, yielding the saturated complexes [(C₆F₅) ₂Pt^II(μ-PPh₂)₂Pt ^II(μ-PPh₂)₂Pt^II(PPh ₃)L] [L = PPh₃ (2), py (3)]. The reaction with the electrophile [Ag(OClO₃)PPh₃] affords the adduct 1·AgPPh₃, which evolves, even at low temperature, to a mixture in which [(C₆F₅)₂Pt^III(μ- PPh₂)₂Pt^III(μ-PPh₂) ₂Pt^II(PPh₃)₂]²⁺(Pt ^III-Pt^III) and 2 (plus silver metal) are present. The nucleophilic nature of 1 is also demonstrated through its reaction with cis-[Pt(C₆F₅)₂(THF)₂], which results in the formation of [Pt₄(μ-PPh₂)₄(C ₆F₅)₄(PPh₃)] (4). The structure and NMR features indicate that 1 can be better considered as a Pt ^II-Pt^III-Pt^I complex instead of a Pt ^II-Pt^II-Pt^II derivative. Theoretical calculations (density functional theory) on similar model compounds are in agreement with the assigned oxidation states of the metal centers. The strong intermetallic interactions resulting in a Pt²-Pt³ metal-metal bond and the respective bonding mechanism were verified by employing a multitude of computational techniques (natural bond order analysis, the Laplacian of the electron density, and localized orbital locator profiles).

Full text of DOI:10.1021/ic3021639

Article
pubs.acs.org/IC
Synthesis and Reactivity of the Unsaturated Trinuclear Phosphanido
Complex [(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(PPh3)]
Juan Fornies,‡ Consuelo Fortuno,*,‡ Susana Ibanez,‡ Antonio Martín,‡ Piero Mastrorilli,*,§ Vito Gallo,§
́
́
̃
̃
and Athanassios Tsipis*,⊥
‡Departamento de Química Inorgan
Zaragoza, Spain
́ ́ ́
ica, Instituto de Síntesis Química y Catalisis Homogenea, Universidad de Zaragoza, CSIC, 50009
§Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (DICATECh), Politecnico di Bari, via Orabona 4,
I-70125 Bari, Italy
⊥Laboratory of Inorganic and General Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
S
* Supporting Information
ABSTRACT: The reaction of [NBu4][(C6F5)2Pt(μ-PPh2)2Pt(μ-
PPh2)2Pt(O,O-acac)] (48 VEC) with [HPPh3][ClO4] gives the
46 VEC unsaturated [(C6 F5 )2 Pt1 (μ-PPh2 )2 Pt2 (μ-
PPh2)2Pt3(PPh3)](Pt2−Pt3) (1), a trinuclear compound en-
dowed with a Pt−Pt bond. This compound displays amphiphilic
behavior and reacts easily with nucleophiles L, yielding the
saturated complexes [(C6 F5 )2 PtI I (μ-PPh2 )2 PtI I (μ-
PPh2)2PtII(PPh3)L] [L = PPh3 (2), py (3)]. The reaction with
the electrophile [Ag(OClO3)PPh3] affords the adduct 1·AgPPh3,
which evolves, even at low temperature, to a mixture in which
[(C6F5)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtII(PPh3)2]2+(PtIII−PtIII)
and 2 (plus silver metal) are present. The nucleophilic nature of
1 is also demonstrated through its reaction with cis-[Pt-
(C6F5)2(THF)2], which results in the formation of [Pt4(μ-PPh2)4(C6F5)4(PPh3)] (4). The structure and NMR features
indicate that 1 can be better considered as a PtII−PtIII−PtI complex instead of a PtII−PtII−PtII derivative. Theoretical calculations
(density functional theory) on similar model compounds are in agreement with the assigned oxidation states of the metal centers.
The strong intermetallic interactions resulting in a Pt2−Pt3 metal−metal bond and the respective bonding mechanism were
verified by employing a multitude of computational techniques (natural bond order analysis, the Laplacian of the electron
density, and localized orbital locator profiles).
one ligand, results in both cases in the formation of a Pt−Pt
bond.10,13,29,30 When a ligand is eliminated in the resulting
binuclear complex, one of the Pt centers is only three-
coordinated.
In this paper, we report a combined experimental and
theoretical study on the unsaturated trinuclear complex
[(C6F5)2Pt1(μ-PPh2)2Pt2(μ-PPh2)2Pt3(PPh3)](Pt2−Pt3) (1),
from which we concluded that 1 should be better considered
a PtII−PtIII−PtI complex instead of a PtII−PtII−PtII one. The
reactivity of 1 toward representative nucleophiles and electro-
philes is also reported.
INTRODUCTION
■
The ability of the phosphanido ligands to stabilize polynuclear
complexes because of their ability to form very stable M−P
bonds is well-known. The PR2 groups usually act as bridging
ligands and display a great geometrical flexibility, which allows
diorganophosphanides to bridge metal centers across a wide
range of M−M distances.2−9
We are engaged in the synthesis of polynuclear platinum
and/or palladium phosphanido complexes, and the judicious
choice of the starting materials and reaction processes has
allowed the rational synthesis of phosphanido complexes of
different nuclearity with or without a metal−metal bond, with
the latter depending on the total valence electron count
(VEC).10−29 Typically, polynuclear platinum or palladium
complexes that contain 16 electrons per metal center, i.e., a
VEC of 16n (n = number of metal centers), are considered to
be saturated and do not require the presence of any metal−
metal bond. For instance, in binuclear phosphanido complexes
studied by us, the elimination of a pair of electrons, either via
one-electron oxidation of each metal center or by elimination of
RESULTS AND DISCUSSION
■
We have recently reported that the trinuclear saturated (48
VEC) acetylacetonato complex [NBu4][(C6F5)2Pt(μ-PPh2)2Pt-
(μ-PPh2)2Pt(O,O-acac)] (A) reacts with HClO4(aq) in
acetonitrile, forming the trinuclear saturated [(C6F5)2Pt(μ-
Received: October 4, 2012
Published: January 28, 2013
© 2013 American Chemical Society
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Scheme 1
PPh2)2Pt(μ-PPh2)2Pt(NCCH3)2] (B) as a result of the
protonation of acetylacetonate, elimination of Hacac, and
coordination of two molecules of acetonitrile (Scheme 1).31
When protonation of A was carried out with [PPh3H][ClO4] in
a noncoordinating solvent, the pale-yellow color of the solution
turned instantaneously red, and from the reaction mixture, the
unsaturated trinuclear complex (46 VEC) 1 could be
crystallized. The unsaturated nature of this complex requires
that a Pt−Pt bond be formed.32
Pt(2)−P(2) and P(3)−Pt(2)−P(4) planes is 31.60(6)°, and
the P−Pt(2)−P angles deviate significantly from the ideal
values of 90 or 180° (see Table 1). As expected, on the basis of
the number of skeletal electrons (46 VEC), Pt(2) is bonded to
Pt(3) with a bond distance of 2.6985(4) Å, a value in the range
expected for a Pt−Pt bond.28,32,33 The smaller values of the
Pt(2)−P(3)−Pt(3) and Pt(2)−P(4)−Pt(3) angles compared
to the analogues involving P(1) and P(2) (see Table 1) are in
agreement with the presence of the intermetallic Pt−Pt bond. It
is worth noting that the environment of Pt(3) is formally three-
coordinated and lies in the center of an almost equilateral
triangle formed by the three P atoms bonded to it. The P(5)
atom of the triphenylphosphane ligand is located practically in
the same line formed by the three Pt atoms, with a Pt(2)−
Pt(3)−P(5) angle of 173.05(5)°. The geometry around Pt(3)
is identical with that found for phosphanidoplatinum(I)
complexes bonded to terminal phosphanes (or phosphinites)
and bridged by diorganophosphanides of the general formula
[(PR1 R2)Pt(μ-PR3 )2Pt(PR4 R5)](Pt−Pt) (R1 = R2 = R4 = R5
The structure of 1 was determined by X-ray diffraction
methods and is reported in Figure 1, with the most relevant
= Me, R3 = tBu; R1 2= R2 = R4 = R5 = Ph, R3 = tBu;34 R1 = R4 =
Me, R2 = R5 = OMe, R3 = cyclo-C6H11;5 R1 = R2 = R3 = R4 = R5
= Ph).35 Considering that the geometry of Pt(2) is reminiscent
of that of the known phosphanido-bridged PtIII atoms, i.e., Pt1/2
in [(C6F5)2Pt1(μ-PPh2)2Pt2(C6F5)2](Pt−Pt),10 [(C6F5)2Pt1(μ-
PPh2)2Pt2(μ-PPh2)2Pt3(O,O-acac)](Pt1−Pt2)+,31 and
[(C6F5)2Pt1(μ-PPh2)2Pt2(μ-PPh2)2Pt3(C6F5)2](Pt1−Pt2),36 the
following hypothesis can be put forward: complex 1 should be
better regarded as a PtII−PtIII−PtI species rather than a PtII−
PtII−PtII complex. Given that such a hypothesis might be
substantiated by analysis of the 195Pt NMR features, we decided
to compare the 195Pt data for 1 with those of the known PtI and
PtIII systems.
2
2
Figure 1. View of the molecular structure of 1.
bond distances and angles listed in Table 1. Complex 1 is a
trinuclear species, with the three Pt atoms forming an almost
linear array [the value of the Pt(1)−Pt(2)−Pt(3) angle is
178.14(1)°]. The coordination environment of Pt(1) is square-
planar, with two pentafluorophenyl ligands mutually cis and
two phosphanido ligands bridging Pt(1) and Pt(2). The
Pt(1)···Pt(2) distance is 3.6760(4) Å, excluding any
intermetallic interaction. Accordingly, the Pt(1)−P(1)−Pt(2)
and Pt(1)−P(2)−Pt(2) angles are broad (ca. 105°; Table 1).
The Pt(2) environment is more distorted, with a coordination
sphere that can be described as intermediate between square-
planar and tetrahedral. The dihedral angle between the P(1)−
Because of the low sensitivity of the 195Pt nucleus and the
37
195
Pt
very large range of values for δ
,
detection of all 195Pt
signals of a polynuclear compound requires the particularly
time-consuming process of registering several spectra, to span
all spectral windows where the 195Pt signals are thought to fall.
In addition, the broadness of some signals lowers their S/N
ratio, thus hampering their detection. To overcome this
drawback, the 195Pt resonances of 1 were recorded by means
of 19F−195Pt and 1H−195Pt heteronuclear multiple-quantum
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Table 1. Selected Bond Lengths (Å) and Angles (deg) for [(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(PPh3)]·0.25CHCl3·0.25C6H14
(1·0.25CHCl3·0.25C6H14)
Pt(1)−C(7)
Pt(1)−P(2)
Pt(2)−P(3)
Pt(3)−P(3)
2.052(6)
Pt(1)−C(1)
Pt(2)−P(2)
Pt(2)−P(4)
Pt(3)−P(5)
2.064(7)
Pt(1)−P(1)
Pt(2)−P(1)
Pt(2)−Pt(3)
Pt(3)−P(4)
2.2706(18)
2.3624(18)
2.6985(4)
2.2306(17)
2.2747(18)
2.3677(17)
2.2181(19)
2.3605(18)
2.3918(19)
2.2254(18)
C(7)−Pt(1)−C(1)
C(1)−Pt(1)−P(1)
C(1)−Pt(1)−P(2)
P(2)−Pt(2)−P(1)
P(1)−Pt(2)−P(3)
P(1)−Pt(2)−P(4)
P(2)−Pt(2)−Pt(3)
P(3)−Pt(2)−Pt(3)
91.3(2)
P(3)−Pt(3)−P(5)
P(5)−Pt(3)−P(4)
Pt(1)−P(2)−Pt(2)
Pt(3)−P(4)−Pt(2)
C(7)−Pt(1)−P(1)
C(7)−Pt(1)−P(2)
P(1)−Pt(1)−P(2)
P(2)−Pt(2)−P(3)
122.50(6)
123.55(7)
104.93(7)
71.34(5)
P(2)−Pt(2)−P(4)
P(3)−Pt(2)−P(4)
P(1)−Pt(2)−Pt(3)
P(4)−Pt(2)−Pt(3)
P(3)−Pt(3)−P(4)
Pt(1)−P(1)−Pt(2)
Pt(3)−P(3)−Pt(2)
95.94(6)
102.95(6)
143.50(4)
51.55(4)
113.64(7)
105.00(7)
72.01(5)
95.38(18)
167.87(18)
73.27(6)
95.76(6)
153.10(6)
143.23(4)
51.42(5)
169.17(19)
97.97(18)
76.64(6)
154.56(7)
coherence (HMQC) NMR experiments, which are faster than
1D 195Pt{1H} NMR experiments because of the higher
the scalar coupling between the o-H of the phenyl rings and Pt
atoms. Once the chemical shifts of each of the three 195Pt
signals were located, their fine structures were obtained by
recording a 1D 195Pt{1H} NMR spectrum (Figure S1 in the
Supporting Information), which showed inter alia a coupling
constant between Pt2 and Pt3 of 515 Hz.
1
sensitivity and abundance of the 19F and H nuclei.
Thus, the 195Pt resonance of Pt1 for 1 (δ −3712) was
revealed by recording a 19F−195Pt HMQC NMR spectrum
(Figure 2), exploiting the strong scalar coupling (3JF,Pt = 312
The chemical shift values observed for 1 substantiate our
hypothesis on the PtII−PtIII−PtI oxidation states of the Pt
atoms in 1. In fact, while the chemical shift of Pt1 is not greatly
affected on passing from [(C6F5)2Pt1(μ-PPh2)2Pt2(μ-
PPh2)2Pt3(O,O-acac)]− (δPt −3793) to the unsaturated 1
1
(δPt −3712), the Pt2 atom experienced a high shielding (from
1
2
2
δPt −3894 to δPt −4720), which has already been observed
upon PtII to PtIII oxidation of phosphanido-bridged polynuclear
complexes,31 and the chemical shift of Pt3 for 1 (δPt −5228) is
3
perfectly in the −5000 to −6000 ppm range of the known
phosphanido-bridged PtI complexes2 (the chemical shift of Pt3
3
in the precursor is δPt −3159).
The same argument (i.e., the occurrence of a PtI−PtIII system
instead of a PtII−PtII one) might be thought to apply to
complex [(C6F5)2Pt1(μ-PPh2)2Pt2PPh3](Pt1−Pt2) (C), for
which the geometric parameters of Pt1 and Pt2 perfectly fit
those of PtIII and PtI phosphanido-bridged atoms, respectively.
Figure 2. Portions of the 19F−195Pt HMQC NMR spectrum of 1
(CDCl3, 298 K).
The 195Pt NMR signals of C were found at δPt −5369 and δPt
1
2
1
−5354, with a JPt,Pt of 407 Hz, while the corresponding data
for its precursor [(C6F5)2Pt1(μ-PPh2)2Pt2(O,O-acac)] are δPt
Hz) between the o-F of the pentafluorophenyl rings and Pt1.
On the other hand, the Pt2 and Pt3 signals of 1 (δ −4720 and
1
2
−3236 and δPt −3934. This confirms our previous
observation31 that 195Pt chemical shifts of phosphanido-bridged
polynuclear complexes are strongly dependent on the geometry
1
−5228, respectively) were obtained by recording a H−195Pt
HMQC NMR spectrum (Figure 3), which was set to exploit
1
Figure 3. Portions of the H−195Pt HMQC NMR spectrum of 1 (CDCl3, 298 K).
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195Pt) using as starting chemical shifts and coupling constants
those extractable directly from the experimental 31P{1H} and
31P{1H} COSY NMR spectra.
around the Pt atom, with the presence of the Pt2P2 ring
endowed with a Pt−Pt bond resulting in 195Pt NMR signals
high-field-shifted with respect to their analogues for a Pt2P2 ring
not endowed with a Pt−Pt bond. As can be seen below, the
195Pt chemical shifts of 1 show the same tendency as the 195Pt
chemical shifts calculated for the model complexes.
The comparison between the calculated and experimental
31P{1H} NMR spectra is shown in Figure S2 in the Supporting
Information. The value of 45 Hz calculated for the coupling
constant between P1 and P3 (or P2 and P4), which is higher
than those expected for cis-P ligands in a square-planar
geometry (Jcis < 20 Hz),38 indicates that the geometry of Pt2
found in the solid state (which we have described as
intermediate between square-planar and tetrahedral) is
maintained in solution.
Reactivity of 1 toward Nucleophiles or Electrophiles.
Unsaturated complexes analogous to 1 were shown to be able
to react with nucleophiles, producing saturated derivatives (16n
VEC, where n is the number of Pt, or Pd, atoms present in the
molecule; Scheme 2).30 Thus, the reaction of 1 with PPh3 or
The 31P{1H} NMR spectrum of 1 in deuterochloroform
showed three signals according to the presence of three
different types of P atoms. The spectrum shows a low-field
signal centered at δ 236.7 due to the P atoms of the PPh2
groups (P3 and P4) bridging two Pt atoms (Pt2 and Pt3)
subtending a metal−metal bond, a signal centered at δ 42.5
assigned to the PPh3 ligand (P5), and a high-field signal at δ
−158.9 due to the P atoms of the other two PPh2 groups (P1
and P2). The 31P{1H} correlation spectroscopy (COSY) NMR
Scheme 2
pyridine in CH2Cl2 resulted in a sudden red-to-yellow color
change of the solution from which a yellow solid formulated as
[(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(PPh3)L] [L = PPh3 (2),28
py (3); Scheme 1] was isolated. Unfortunately, 2 and 3 are very
insoluble in all common organic solvents, precluding a
complete characterization. In all likelihood, the saturated
complexes 2 and 3 do not display M−M bonds as for
[NBu4][(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(acac)].31
Figure 4. Portions of the 31P{1H} COSY NMR spectrum of 1 (CDCl3,
298 K).
spectrum (Figure 4) allowed us to unequivocally determine the
31P−195Pt coupling constants that were not directly extractable
from 1D 31P{1H} NMR spectra because of overlapping of the
195Pt satellites. All signals appear as complex multiplets because
of the second-order spin systems to which this molecule
belongs at a field of 161 MHz. The 31P features of 1 (Table 2)
were determined by computer simulation of the AA′XX′M
(29.0%), AA′XX′MZ (14.8% for each of the three iso-
topomers), and AA′XX′MZY (7.6% for each of the three
isotopomers) spin systems (A, X, and M = 31P; Y and Z =
On the other hand, we have shown that in complex
[(C6F5)2Pt1(μ-PPh2)2Pt2(PPh3)] (C) the μ-P−Pt2 bond is
+
electron-rich and reacts with electrophiles such as AgPPh3 ,
giving trinuclear complexes with the Pt−Ag bond.39 This
behavior is in full agreement with the hypothesis of the different
oxidation states of Pt1(III) and Pt2(I), thus more electron-rich.
We have carried out the reaction of 1 with [Ag(OClO3)PPh3]
(1:1 molar ratio, room temperature) in dichloromethane, which
resulted in the formation of a mixture of compounds and of a
silver mirror. Multinuclear NMR spectroscopy revealed signals
due to the previously reported28 complex [(C6F5)2PtIII(μ-
PPh2)2PtIII(μ-PPh2)2PtII(PPh3)2]2+ along with signals belonging
to unidentified species. These findings indicate that the
a
Table 2. NMR Parameters for 1 (CDCl3, 298 K)
+
b
c
P1
P3
P5
8
Pt1
Pt2
Pt3
15
treatment of 1 with AgPPh3 does not result in the formation
of the 1:1 adduct 1·AgPPh3 displaying a Pt−P−Ag (three-
center two-electron, 3c-2e) bond such as occurs in the case of
the analogous dinuclear complex C (Scheme 2)28,39 but in a
redox process. When 1 was mixed with [Ag(OClO3)PPh3] (1:1
molar ratio, dichloromethane) at 273 K and the resulting
solution was immediately evaporated to dryness, a red solid was
obtained, which was analyzed by 31P and 19F NMR spectros-
copy. In the 31P{1H} NMR spectrum of the solid redissolved in
CD2Cl2 at 193 K, beside the signals of [(C6F5)2PtIII(μ-
PPh2)2PtIII(μ-PPh2)2PtII(PPh3)2]2+ and other unidentified
P1
−158.9
45
1860
1738
1111
32
P3
236.7
72
42.5
2789
5440
P5
Pt1
Pt2
Pt3
−3712
−4720
515
−5228
a
Chemical shifts (bold typeface) are in parts per million; coupling
b
c
2
2
constants (normal type) are in hertz. JP(1),P(2) = 150 Hz. JP(3),P(4)
55 Hz; JP(1),P(4) = 125 Hz.
=
2
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Scheme 3
Scheme 4
Figure 5. Equilibrium structures of the model compounds M1−M5 computed at the PBE0/Def2-TZVP(Pt)U6-31+G(d,p)(X) level of theory.
species, two signals at δ 281 and δ 191 were assigned to P3 and
P4, respectively, of the fragment of the type “Pt(μ-PPh2)2Pt-
{Ag(PPh3)}” (Scheme 3), in which a μ-P4−Pt bond donates
electron density to the Ag center (possibly the adduct
[1·Ag(PPh3)]+. This indicates that, even though a 1:1 adduct
1·AgPPh3 could be initially formed, it evolves through a redox
process to form the trinuclear [PtIII−PtIII−PtII]2+ cation along
with the saturated and insoluble complex 2.
The electron-rich character of the Pt−P bond in 1 is clearly
demonstrated by the reaction of 1 with cis-[Pt(C6F5)2(THF)2],
a well-known Pt(C6F5)2 synthon.40,41 This reaction (1:1 molar
ratio) in CH2Cl2 yielded [Pt4(μ-PPh2)4(C6F5)4(PPh3)] (4),
which had already been synthesized in our laboratories through
a different process.42 A plausible mechanism for the formation
of 4 is shown in Scheme 4, in which the donor behavior of a μ-
P−Pt bond is considered.16,43,44
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Figure 6. 3D contour plots of the HOMOs, LUMOs, and most relevant to the Pt−Pt bonding mode MOs in compounds M1−M3.
Electronic Properties and the Nature of the Inter-
metallic Pt−Pt Bond. In order to obtain a computationally
convenient size for the compounds, we used models resulting
upon substitution of the phenyl groups of the phosphanido
ligands by methyl groups. To unveil the nature of the
intermetallic Pt−Pt bond, we performed density functional
theory (DFT) calculations on the dinuclear complexes
[(Cl2Pt(μ-PMe2)2Pt(PMe3)] (M1) and [(C6F5)2Pt(μ-
PMe2)2Pt(PMe3)] (M2), which exhibit strong intermetallic
Pt···Pt interactions, and on the trinuclear model compounds
[(C6F5)2Pt(μ-PMe2)2Pt(μ-PMe2)2Pt(PMe3)] (M3),
[(C6F5)2Pt(μ-PMe2)2Pt(μ-PMe2)2Pt(O,O-acac)]− (M4), and
[(C6F5)2Pt(μ-PMe2)2Pt(μ-PMe2)2Pt(PMe3)(py)] (M5) at the
PBE0/Def2-TZVP(Pt)U6-31+G(d,p)(X) level. The optimized
geometries of M1−M5 are shown in Figure 5.
The equilibrium structures of the model systems M3 and M4
resemble those of the “real” complexes 1 and A, respectively,
with the expected small structural variations due to the
electronic and steric effects of the respective ligands. In general,
the computed bond lengths of M3 and M4 model systems
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2
▽
Scheme 5. Laplacian of the Electron Density,
M1−M5
ρ(r), Map on the xy Plane (Contour Value = 0.1) of the Model Compounds
a
a
Brown, blue, and orange circles denote (3, −3), (3, −1), and (3, +1) critical points, respectively.
exhibit elongation, in the ranges 0−0.036 and 0−0.045 Å,
respectively, upon comparison to those obtained from X-ray
structural analysis of 1 and A. On the other hand, deviations of
the computed bond angles of M3 and M4 upon comparison
with the respective X-ray analysis structural parameters fall
within the ranges 0−3.5° and 0.3−2.4°, respectively. In the
optimized geometries of all model compounds, the coordina-
tion environments of the central as well as terminal Pt atoms
are planar. However, only in M3, the Pt metal centers are in an
almost perfect linear alignment (∠Pt1−Pt2−Pt3 = 179.7°),
while in the other two model compounds M4 and M5, the
∠Pt1−Pt2−Pt3 bond angles of the Pt1−Pt2−Pt3 nuclear
framework are estimated to be 174.1° and 170.3°.
Accordingly, in M4 and M5, the coordination environments
of the Pt metal centers adopt a “chair”-like conformation, while
in M3, an almost coplanar orientation could be observed. It is
worth noting that in the model compounds M4 and M5 the
two Pt2P2 rhombuses are not planar, in contrast to those found
for M3. In the latter, the planes of the two rhombuses form an
angle equal to 49.8° with Pt−μ-P−Pt bridges in syn positions.
The computed Pt−Pt distances are found to be well above the
sum of the van der Waals radii of two Pt atoms (3.5 Å) with the
exception of the Pt2−Pt3 distance in M3, which is estimated to
be equal to 2.713 Å, in line with the X-ray structure analysis.
This is indicative of a strong intermetallic interaction resulting
in a Pt2−Pt3 metal−metal bond in 1 and in its model
compound M3. Strong intermetallic interactions also exist in
the compounds M1 and M2 exhibiting short Pt−Pt distances of
2.670 and 2.686 Å, respectively.
compounds M1 and M2 are localized on the coordination
environment of Pt2 and are constructed from bonding
2
2
combinations of Pt dx −y atomic orbitals (AOs) with ligand
group orbitals of the phosphanido bridging and phosphane
ligands. On the other hand, the HOMO in M3 is localized on
the coordination environment of Pt1 constructed from bonding
2
2
combinations of Pt dx −y AOs with ligand group orbitals of the
phosphanido bridging and C6F5 ligands. The LUMOs are
located on the Pt1(μ2-PMe2)Pt2 framework in M1 and M2 and
on Pt2(μ2-PMe2)Pt3 framework in M3 involving overlap of
PMe3 p-type orbitals with 5d AOs of Pt centers. The Pt1−Pt2
bonding mechanism in M1−M3 is reflected in the occupied
MOs (Figure 6), which are of both σ- and π-type bonding
MOs.
The Pt1−Pt2 bonding mode was further corroborated from
the Laplacian of the electron density, ▽2ρ(r), obtained from
topological analysis performed by the atoms-in-molecules
calculations (Scheme 5) introduced by Bader.45
Topological analysis involves the search for critical points,
which are extremes in the 3D function ρ(r), that is, points
where ▽ρ(r) = (0, 0, 0). A set of trajectories of ρ(r)
terminating in the bond critical point (bcp) defines an
interatomic surface that separates the basins of neighboring
atoms. Trajectories connecting two atoms via the bcp describe
the line of maximum density, which corresponds to bond paths
in equilibrium geometry. The Laplacian of the electron density,
▽2ρ(r), indicates relative charge concentrations [▽2ρ(r) < 0]
and charge depletion [▽2ρ(r) > 0] in a molecule.
It is clear from Scheme 5 that there is charge concentration
only between two out of the three Pt metal atoms. A bcp with
(3, −1) signature was found in the midpoint between the two
interacting Pt metal centers of the model compounds M1−M3
(blue circles in Scheme 5). The Laplacian of the electron
The highest occupied molecular orbital (HOMO) and the
lowest unoccupied molecular orbital (LUMO) along with
molecular orbitals (MOs) that are most relevant to the Pt−Pt
bonding mode are shown in Figure 6. The HOMOs in the
1948
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Scheme 6. Cut-Plane LOL Profiles of the Model Compounds M1−M5
Figure 7. Data from NBO analysis along with the calculated 195Pt chemical shifts for compounds M1−M5.
1949
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Inorganic Chemistry
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Figure 8. Natural charge transferred from the ligands to the metal centers in M1−M5.
density, ▽2ρ(r)bcp, calculated for this bcp is small and negative
(e.g., −0.0046 e Å−5 for M3), indicating a covalent interaction
(also referred to as an “open-shell” or sharing interaction).46 In
contrast, between the central Pt metal atom paired with the Pt
metal atom on the opposite site, only a ring critical point with
(3, +1) signature could be observed (orange circle in Scheme
5).
The spatial organization of the bonding mechanism in the
model compounds M1−M5 can easily be recognized by the
cut-plane localized orbital locator (LOL) profiles depicted in
Scheme 6.
Identification of LOL basins such as atomic shells, bonds,
and lone electron pairs is reflective47,48 of the nature of the
electronic structure of the investigated systems. The LOL
function relies on consideration of the electron kinetic energy
density and reveals slow electron regions compared to the
uniform electron gas (LOL > 0.5). The slowest electron regions
are located between the bonded atoms that correspond to a
typical 2c-2e bonding situation (shown in yellow-red). The
green LOL basins located between the interacting Pt−Pt atoms
(LOL ≥ 0.5) are typical of weak Pt−Pt and multicenter
bonding. Lone pairs are visible as deep-red sickles on the atoms.
The remaining colors (lighter blue, blue, and deep blue)
corresponding to 0.0 < LOL < 0.5 represent regions in space
that are increasingly avoided by electrons, such as the space far
away from nuclei and the space between the shells of the atoms.
Natural Bond Orbital (NBO) Analysis and Oxidation
States of the Pt Metal Centers. 195Pt NMR Chemical
Shifts. To shed more light on the Pt−Pt bonding situation in
compounds M1−M3, a bonding analysis was carried out within
the framework of the NBO analysis method.49 The estimated
natural atomic charges, natural electron configurations (Nec) of
the Pt metal centers, Wiberg bond orders (WBOs) for the Pt−
Pt bonds, along with the 195Pt chemical shifts calculated at the
GIAO/PBE0/SARCZORA(Pt)∪6-31G**(E) level, are col-
lected in Figure 7.
The WBO values for the Pt1−Pt2 bonds in compounds M1
and M2 and for the Pt2−Pt3 bond in compound M3 found in
the range of 0.164−0.307 confirm the existence of strong Pt−Pt
interactions. It should be noted that a WBO(Pt−Pt) value of
around 1 corresponds to a single bond. On the other hand, the
Nec of the Pt metal centers indicated participation of the 6s, 5d,
and 6p AOs of the Pt centers in the bonding in all complexes
M1−M5. The participation of 6s orbitals accounts for the direct
1JPt,Pt observed for such complexes. The calculated 195Pt
chemical shifts were found in the range of −6560 to −6701
ppm for the Pt2(I) metal centers in complexes M1 and M2 and
the Pt3(I) metal center in complex M3, −5893 to −6243 ppm
for the Pt1(III) centers in complexes M1 and M2 and the
Pt2(III) center in complex M3, and −4385 to −5047 ppm for
the Pt1(II) centers in M3 and in all PtII centers in complexes
M4 and M5.
To estimate the oxidation states of the Pt centers in
complexes M1−M5, we calculated the natural charge trans-
ferred from the ligands to the metal centers, and the results are
compiled in Figure 8.
The charge transferred from the ligands toward the metal
centers was estimated as the difference between the total
natural charges on the “free-standing” and coordinated ligands.
The natural charge transferred combined with the natural
atomic charges on the Pt centers allowed us to assign the
oxidation states of the Pt centers in complexes M1−M5. For
complexes M1−M3, according to the LOL profiles, the
bonding electron pairs of the dative coordination bonds are
closer to the more electrophilic PtIII centers than the less
electrophilic PtI centers. Therefore, the charge transferred from
the bridging PMe2 moieties toward the more electrophilic
Pt1(III) centers in M1 and M2 and Pt2(III) in M3 should be
higher than that toward the less electrophilic Pt2(I) centers in
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Inorganic Chemistry
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M1 and M2 and the Pt3(I) center in M3. Moreover, according
to the electroneutrality principle, the dative coordination P−
PtIII bonds exhibit higher ionic character than the P−PtI ones,
thus rendering the PtIII centers better acceptors of electron
density from the bridging electron-donor phosphanido ligands
than the PtI centers. Accordingly, the charges transferred from
the ligands toward the Pt metal centers mapped in Figure 8
allowed the assignment of the respective oxidation states on the
Pt metal centers.
0.500 g, 0.250 mmol) in CH2Cl2 (30 mL). The solution, which
instantaneously turned red, was stirred for 30 min at room
temperature. The red solution was passed through silica (ca. 15 cm
× 2 cm2) and evaporated to ca. 2 mL. The addition of n-hexane (ca. 2
mL) caused the precipitation of 1 as red crystals, which were filtered
and washed with n-hexane (3 × 0.5 mL). Yield: 0.317 g, 66%. Anal.
Found (calcd for C78F10H55P5Pt3): C, 48.71 (48.73); H, 2.86 (2.88).
IR (cm−1): 785 and 778 (X-sensitive C6F5).53,54 19F NMR (CDCl3,
3
195
298 K, 282.4 MHz): −119.0 (o-F, J Pt,F = 312 Hz), −168.1 (m-F + p-
F). 31P{1H} NMR (CDCl3, 298 K, 161.9 MHz): δ 236.7 (P3,4, 1JPt ,P
=
3
1
1
2789, JPt ,P = 1111 Hz), 42.5 (P5, JPt ,P = 5440 Hz), −158.9 (P1,2,
2
3
JPt ,P = 1860, JPt ,P = 1738 Hz). 195Pt NMR (CDCl3, 298 K, 85.6
1
1
1
2
CONCLUDING REMARKS
■
MHz): δ −3712 (Pt1, m), −4720 (Pt2, tt), −5228 (Pt3, dt, JPt ,Pt
=
1
2
3
The trinuclear 48 VEC A, having a linear skeleton, phosphanido
groups as bridging ligands, and four-coordinated metal centers
(without any Pt−Pt bond), is transformed into the unsaturated
1 (46 VEC) by substitution of the acac ligand by PPh3. In
complex 1, two Pt centers are four-coordinated and one is
three-coordinated. Such unsaturation of the skeleton entails the
formation of a Pt−Pt bond.11,15,50 The process is reversible
because the addition of a ligand (PPh3 or pyridine) to the red
and unsaturated 1 forms the yellow and saturated complexes 2
and 3, respectively. The trinuclear 1 reacts also with
electrophiles. Although 1 reacts with [AgPPh3]+, in a 1:1
molar ratio, we were not able to isolate the adduct [1·AgPPh3]+,
which should be expected to be formed through a 3c-2e P4−
Pt3−Ag bond. On the contrary, we have obtained a mixture of
complexes [(C6F5)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtII(PPh3)2]2+
and [(C6F5)2PtII(μ-PPh2)2PtII(μ-PPh2)2PtII(PPh3)2], which are
the final result of the coordination of PPh3 and the oxidation by
Ag+. The electron-rich character of the Pt3−μ-P4 bond, i.e., the
nucleophilic character of 1, is demonstrated by its reaction with
[Pt(C6F5)2(THF)2], which yields the tetranuclear 4. Formation
of the adduct [1·Pt(C6F5)2], followed by some ligand
rearrangement,42−44,51 can safely explain the isolation of 4.
The strong intermetallic interactions resulting in a Pt2−Pt3
metal−metal bond along with the respective bonding
mechanism were verified by employing a multitude of
computational techniques (NBO analysis, Laplacian of the
electron density, and LOL profiles). The oxidation states of the
Pt centers in the complexes under investigation were estimated
by calculation of the natural charges transferred from the
ligands toward the Pt metal centers combined with the natural
atomic charges acquired by the Pt centers.
515 Hz).
Synthesis of [(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(PPh3)(L)] [L = PPh3
(2), py (3)]. PPh3 (0.050 g, 0.190 mmol) or py (0.1 mL, 1.2 mmol) was
added to a red solution of 1 (0.200 g, 0.104 mmol) in CH2Cl2 (10
mL). The color of the solution instantaneously turned yellow, and a
yellow solid precipitated, 2 or 3. The solid was filtered and washed
with cold CH2Cl2 (3 × 0.5 mL). Yield of 2:28 0.197 g, 87%. Yield of 3:
0.175 g, 84%. Anal. Found (calcd for C83F10H60NP5Pt3): C, 49.60
(49.81); H, 2.81 (3.02); N, 0.63 (0.70). IR (cm−1): 1603 (pyridine);
780 and 771 (X-sensitive C6F5).
Reaction of 1 with cis-[Pt(C6F5)2(THF)2]. cis-[Pt(C6F5)2(THF)2]
(0.035 g, 0.052 mmol) was added to a red solution of 1 (0.100 g, 0.052
mmol) in CH2Cl2 (15 mL). The solution was stirred for 24 h and
evaporated to ca. 0.5 mL. CHCl3 (2 mL) and n-hexane (10 mL) were
added with stirring. An orange solid precipitated and was filtered and
washed with n-hexane (3 × 1 mL, 0.085 g). The 31P{1H} NMR
(CDCl3, 298 K) spectrum of the solid is mainly 4,42 together with 1
(ca. 20%).
X-ray Structure Determination of 1·0.25CHCl3·0.25C6H14.
Crystal data and other details of structure analysis are presented in
Table 3. Suitable crystals for X-ray diffraction studies were obtained by
slow diffusion of n-hexane into a concentrated solution of complex 1 in
3 mL of CHCl3. The crystal was mounted at the end of a quartz fiber.
The radiation used in all cases was graphite-monochromated Mo Kα
(α = 0.71073 Å). X-ray intensity data were collected on a Bruker Smart
Table 3. Crystal Data and Structure Refinement for Complex
1·0.25CHCl3·0.25C6H14
formula
Mt [g mol−1
T [K]
C78H55F10P5Pt3·0.25CHCl3·0.25C6H14
1973.73
]
100(1)
λ [Å]
0.71073
From 195Pt NMR spectra and theoretical calculations, it can
be inferred that the oxidation states of the Pt atoms in the
trinuclear metal core are [PtII, PtII, PtII] in [(C6F5)2Pt(μ-
PPh2)2Pt(μ-PPh2)2Pt(O,O-acac)]− but should be considered
[PtII, PtIII, PtI] in 1.
cryst syst
space group
a [Å]
monoclinic
P21/n
16.0336(11)
b [Å]
19.2639(13)
c [Å]
19.2639(13)
β [deg]
V [Å3]
Z
101.592(1)
EXPERIMENTAL SECTION
7035.1(8)
■
4
General Comments. C, H, and N analyses were performed with a
Perkin-Elmer 240B microanalyzer. IR spectra were recorded on a
Perkin-Elmer Spectrum One spectrophotometer (Nujol mulls between
polyethylene plates in the range 4000−350 cm−1). NMR spectra were
recorded on a Bruker Avance 400 spectrometer with CFCl3, 85%
H3PO4, and H2PtCl6 as external references for 19F, 31P, and 195Pt,
respectively. Literature methods were used to prepare the starting
materials [NBu4][(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(acac)]31 and cis-
[Pt(C6F5)2(THF)2].40
Safety Note. Caution! Perchlorate salts of metal complexes with
organic ligands are potentially explosive. Only small amounts of materials
should be prepared, and these should be handled with great caution.
Synthesis of [(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(PPh3)] (1). Solid
[PPh3H][ClO4]52 (0.090 g, 0.250 mmol) was added to a yellow
solution of [NBu4][(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(O,O-acac)] (A;
ρ [g cm−3
]
1.863
μ [mm−1
]
6.165
F(000)
3796
2θ range [deg]
2.8−50.1
37505
no. of reflns collected
no. of unique reflns
R(int)
12373
0.0593
a
final R indices [I > 2σ(I)]
R indices (all data)
GOF on F2
R1 = 0.0360, wR2 = 0.0568
R1 = 0.0529, wR2 = 0.0588
0.991
b
a
R1 = ∑(|Fo| − |Fc|)/∑|Fo|. wR2 = [∑w(Fo − Fc2)2/∑w(Fo )2]1/2
.
2
2
b
GOF = [∑w(Fo − Fc2)2/(nobs − nparam)]1/2
.
2
1951
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Article
Apex diffractometer. The diffraction frames were integrated using the
SAINT program55 and the reflections corrected from absorption with
SADABS.56
a sabbatical leave and all colleagues at the Departamento de
́
́ ́
́ ́
ica, Instituto de Sintesis Quimica y Catalisis
Quimica Inorgan
Homogenea, Facultad de Ciencias, Universidad de Zaragoza,
́
The structures were solved by Patterson and Fourier methods and
refined by full-matrix least squares on F2 with SHELXL-97.57 All non-
H atoms were assigned anisotropic displacement parameters and
refined without positional constraints, except as noted below. All H
atoms were constrained to idealized geometries and assigned isotropic
displacement parameters equal to 1.2 times the Uiso values of their
attached parent atoms (1.5 times for the methyl H atoms). Molecules
of chloroform and n-hexane solvents were found, located in the same
area of the cell, near an inversion center and modeled with a partial
occupancy of 0.25. For these solvent molecules, the interatomic
distances were restrained to sensible values and a common thermal
anisotropic set of parameters was used for the C atoms of n-hexane.
Full-matrix least-squares refinement of these models against F2
converged to the final residual indices given in Table 3.
CSIC, Zaragoza (Spain), for their generous hospitality. Italian
MIUR (PRIN Project 2009LR88XR) and COST Phosphorus
Science Network (PhoSciNet, Project CM0802) are also
gratefully acknowledged.
REFERENCES
(1) Arias, A.; Fornies
Mastrorilli, P.; Todisco, S.; Gallo, V. Inorg. Chem. 2012, 51, 12628−
12696.
■
́
, F.; Fortuno, C.; Martín, A.; Latronico, M.;
̃
(2) Mastrorilli, P. Eur. J. Inorg. Chem. 2008, 4835−4850.
(3) Bender, R.; Okio, C.; Welter, R.; Braunstein, P. Dalton Trans.
2009, 4901−4907.
(4) Cavazza, C.; Fabrizi de Biani, F.; Funaioli, T.; Leoni, P.;
Marchetti, F.; Marchetti, L.; Zanello, P. Inorg. Chem. 2009, 48, 1385−
1397.
(5) Gallo, V.; Latronico, M.; Mastrorilli, P.; Nobile, C. F.; Suranna, G.
P.; Ciccarella, G.; Englert, U. Eur. J. Inorg. Chem. 2005, 4607−4616.
(6) Latronico, M.; Polini, F.; Gallo, V.; Mastrorilli, P.; Calmuschi-
COMPUTATIONAL DETAILS
■
The geometries of all stationary points were fully optimized, without
symmetry constraints, employing the 1997 hybrid functional of
Perdew, Burke, and Ernzerhof,58 as implemented in the Gaussian03
program suite.59 This functional uses 25% exchange and 75%
correlation weighting and is denoted as PBE0. The selection of the
PBE0 functional was based on the fact that PBE0 generally gives the
best results for various properties of transition-metal, lanthanide,
actinide, and main-group-element compounds.60−63 For the geometry
optimizations, we used the Def2-TZVP basis set for Pt and 6-
31G**(E) for all other nonmetal atoms E. Hereafter the method used
in DFT calculations is abbreviated as PBE0/Def2-TZVP(Pt)U6-
31**G(E) (E = nonmetal element). All stationary points have been
identified as minima (number of imaginary frequencies NImag = 0).
NBO population analysis was performed using Weinhold’s
methodology.49,64 Magnetic shielding tensors have been computed
with the gauge-including atomic orbitals (GIAO) DFT method,65,66 as
implemented in the Gaussian03 series of programs59 employing the
PBE0 level of theory combined with the SARCZORA basis set67,68 for
Pt and 6-31**(E) for all other nonmetal elements E. The Laplacian of
electron density and the LOL plots were obtained by employing the
Multiwfn software version 2.2.1.69
Cula, B.; Englert, U.; Re, N.; Repo, T.; Raisanen, M. Inorg. Chem.
̈
̈
2008, 47, 9779−9796.
(7) Archambault, C.; Bender, R.; Braunstein, P.; Dusausoy, Y. J.
Chem. Soc., Dalton Trans. 2002, 4084−4090.
(8) Albinati, A.; Balzanot, F.; Fabrizi de Biani, F.; Leoni, P.; Manca,
G.; Marchetti, L.; Rizzato, S.; Barretta, U. G. Inorg. Chem. 2010, 49,
3714−3720.
(9) Gallo, V.; Latronico, M.; Mastrorilli, P.; Nobile, C. F.; Polini, F.;
Re, N.; Englert, U. Inorg. Chem. 2008, 47, 4785−4795.
́
(10) Alonso, E.; Casas, J. M.; Cotton, F. A.; Feng, X. J.; Fornies, J.;
Fortuno, C.; Tomas
́
, M. Inorg. Chem. 1999, 38, 5034−5040.
(11) Falvello, L. R.; Fornies, J.; Fortuno, C.; Duran, F.; Martín, A.
Organometallics 2002, 21, 2226−2234.
(12) Alonso, E.; Fornies, J.; Fortuno, C.; Martín, A.; Orpen, A. G.
Organometallics 2003, 22, 5011−5019.
(13) Ara, I.; Chaouche, N.; Fornies, J.; Fortuno, C.; Kribii, A.; Tsipis,
̃
́
́
̃
́
̃
́
̃
A. C. Organometallics 2006, 25, 1084−1091.
́
(14) Berenguer, J. R.; Chaouche, N.; Fornies, J.; Fortuno, C.; Martín,
̃
A. New J. Chem. 2006, 30, 473−478.
ASSOCIATED CONTENT
* Supporting Information
■
(15) Fornies, J.; Fortuno, C.; Gil, R.; Martín, A. Inorg. Chem. 2005,
́
̃
S
44, 9534−9541.
́ ́
(16) Fornies, J.; Fortuno, C.; Ibanez, S.; Martín, A. Inorg. Chem.
̃ ̃
Crystallographic data of 1·0.25CHCl3·0.25C6H14) in CIF
format, some NMR spectra, and Cartessian coordinates and
energies of M1−M5. This material is available free of charge via
the Internet at http://pubs.acs.org.
2006, 45, 4850−4858.
(17) Fornies, J.; Fortuno, C.; Iban
Tsipis, C. A. Angew. Chem., Int. Ed. 2005, 44, 2407−2410.
(18) Fornies, J.; Fortuno, C.; Ibanez, S.; Martín, A.; Romero, P.;
́
́
ez, S.; Martín, A.; Tsipis, A. C.;
̃
̃
́
́
̃
̃
Mastrorilli, P.; Gallo, V. Inorg. Chem. 2011, 50, 285−298.
(19) Latronico, M.; Mastrorilli, P.; Gallo, V.; Dell’Anna, M. M.;
Creati, F.; Re, N.; Englert, U. Inorg. Chem. 2011, 50, 3539−3558.
(20) Mastrorilli, P.; Latronico, M.; Gallo, V.; Polini, F.; Re, N.;
Marrone, A.; Gobetto, R.; Ellena, S. J. Am. Chem. Soc. 2010, 132,
4752−4765.
AUTHOR INFORMATION
Corresponding Author
*E-mail: cfortuno@unizar.es (C.F.), p.mastrorilli@poliba.it
(P.M.), attsipis@uoi.gr (A.T.).
Notes
■
́
(21) Dell’Anna, M. M.; Giardina-Papa, D.; Ibanez, S.; Martín, A.;
̃
The authors declare no competing financial interest.
Mastrorilli, P.; Nobile, C. F.; Peruzzini, M. Eur. J. Inorg. Chem. 2009,
4454−4463.
Polynuclear Homo- or Heterometallic Palladium(II)−
Platinum(II) Pentafluorophenyl Complexes Containing Bridg-
ing Diphenylphosphido Ligands. 30. For part 29, see ref 1.
(22) Mastrorilli, P. Dalton Trans. 2008, 4555−4557.
(23) Dell’Anna, M. M.; Mastrorilli, P.; Nobile, C. F.; Calmuschi-Cula,
B.; Englert, U.; Peruzzini, M. Dalton Trans. 2008, 6005−6013.
(24) Dell’Anna, M. M.; Englert, U.; Latronico, M.; Luis, P. L.;
Mastrorilli, P.; Giardina-Papa, D.; Nobile, C. F.; Peruzzini, M. Inorg.
Chem. 2006, 45, 6892−6900.
ACKNOWLEDGMENTS
This work was supported by the Spanish MICINN (DGI)/
FEDER (Project CTQ2008-06669-C02-01/BQU) and the
■
(25) Mastrorilli, P.; Nobile, C. F.; Fanizzi, F. P.; Latronico, M.; Hu,
C.; Englert, U. Eur. J. Inorg. Chem. 2002, 1210−1218.
(26) Mastrorilli, P.; Palma, M.; Nobile, C. F.; Fanizzi, F. P. J. Chem.
Soc., Dalton Trans. 2000, 4272−4276.
(27) Giannandrea, R.; Mastrorilli, P.; Nobile, C. F.; Englert, U. J.
Chem. Soc., Dalton Trans. 1997, 1355−1358.
́
Gobierno de Arago
Inorganica y de los Compuestos Organometal
gratefully acknowledges a grant provided by the Ministerio de
Educacion y Ciencia. A.T. thanks the University of Ioannina for
́
n (Grupo de Excelencia: Quimica
́
́
icos). S.I.
́
1952
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Article
(28) Fornies
́
, F.; Fortuno, C.; Iban
́
ez, S.; Martín, A.; Mastrorilli, P.;
(63) Vlaisavljevich, B.; Mir, P.; Cramer, C. J.; Gagliardi, L.; Infante, I.;
Liddle, S. T. Chem.Eur. J. 2011, 17, 8424−8433.
(64) Weinhold, F. In The Encyclopedia of Computational Chemistry;
Schleyer, P. v. R., Ed.; John Wiley & Sons: Chichester, U.K., 1998.
(65) Ditchfield, R. Mol. Phys. 1974, 27, 789−809.
̃
̃
Gallo, V. Inorg. Chem. 2011, 50, 10798−10809.
́
(29) Aullon
478, 75−82.
(30) Falvello, L. R.; Fornies
1994, 33, 6242−6246.
(31) Ara, I.; Fornies
́
, G.; Alemany, P.; Alvarez, S. J. Organomet. Chem. 1994,
́
, J.; Fortuno, C.; Martínez, F. Inorg. Chem.
̃
(66) Gauss, J. Chem. Phys. 1993, 99, 3629−3643.
(67) Pantazis, D. A.; Chen, X.-Y.; Landis, C. R.; Neese, F. J. Chem.
Theory Comput. 2008, 4, 908−919.
(68) EMSL basis set exchange, https://bse.pnl.gov/bse/portal,
accessed April 28, 2011.
́
́
, J.; Fortuno, C.; Ibanez, S.; Martín, A.;
̃ ̃
Mastrorilli, P.; Gallo, V. Inorg. Chem. 2008, 47, 9069−9080.
(32) Palacios, A. A.; Alemany, P.; Alvarez, S. J. Chem. Soc., Dalton
Trans. 2002, 2235−2243.
(33) Mealli, C.; Ienco, A.; Galindo, A.; Per
1999, 38, 4620−4625.
(69) Lu, T.; Chen, F. J. Comput. Chem. 2012, 33, 580−592.
́
ez-Carreno, E. Inorg. Chem.
̃
(34) Albinati, A.; Leoni, P.; Marchetti, F.; Marchetti, L.; Pasquali, M.;
Rizzato, S. Eur. J. Inorg. Chem. 2008, 4092−4100.
(35) Taylor, N. J.; Chieh, P. C.; Carty, A. J. J. Chem. Soc., Chem.
Commun. 1975, 448−449.
(36) Alonso, E.; Casas, J. M.; Fornies, J.; Fortuno, C.; Martín, A.;
́
̃
Orpen, A. G.; Tsipis, C. A.; Tsipis, A. C. Organometallics 2001, 20,
5571−5582.
(37) Still, B. M.; Kumar, P. G. A.; Aldrich-Wright, J. R.; Price, W. S.
Chem. Soc. Rev. 2007, 36, 665−686 and references cited therein.
(38) Pregosin, P.; Kunz, R. W. 31P and 13C NMR of Transition Metal
Phosphine Complexes; Springer-Verlag: Berlin, 1979.
(39) Alonso, E.; Fornies
Nova, A. Inorg. Chem. 2009, 48, 7679−7690.
(40) Uson, R.; Fornies, F.; Tomas, M.; Menjon
1985, 4, 1912−1914.
(41) Ara, I.; Chaouche, N.; Fornies
A. Eur. J. Inorg. Chem. 2005, 3894−3901.
(42) Alonso, E.; Fornies, J.; Fortuno, C.; Martín, A.; Orpen, A. G.
Organometallics 2003, 22, 2723−2728.
(43) Alonso, E.; Fornies, J.; Fortuno, C.; Martín, A.; Orpen, A. G.
Chem. Commun. 1996, 231−232.
(44) Alonso, E.; Fornies, J.; Fortuno, C.; Martín, A.; Orpen, A. G.
́
, F.; Fortuno, C.; Lledos
́
, A.; Martín, A.;
̃
́
́
́
́
, B. Organometallics
́
, J.; Fortuno, C.; Kribii, A.; Martín,
̃
́
̃
́
̃
́
̃
Organometallics 2000, 19, 2690−2697.
(45) Bader, R. F. W. Chem. Rev. 1991, 91, 893−928.
(46) Popov, A. A.; Dunsch, L. Chem.Eur. J. 2009, 15, 9707−9729.
(47) Schmider, H. L.; Becke, A. D. J. Mol. Struct. (THEOCHEM)
2000, 527, 51−61.
(48) Schmider, H. L.; Becke, A. D. J. Chem. Phys. 2002, 116, 3184−
3193.
(49) Reed, A. E.; Curtiss, L. A.; Weinhold, F. Chem. Rev. 1988, 88,
899−926.
(50) Fornies
2008, 47, 5978−5987.
(51) Chaouche, N.; Fornies
́
, J.; Fortuno, C.; Ibanez, S.; Martín, A. Inorg. Chem.
́
̃
̃
́
, J.; Fortuno, C.; Kribii, A.; Martín, A. J.
̃
Organomet. Chem. 2007, 692, 1168−1172.
(52) Zhu, J.; Dai, J.-X.; Zhang, Q.-F. Acta Crystallogr. 2007, E63,
o363−o364.
́ ́
(53) Uson, R.; Fornies, J. Adv. Organomet. Chem. 1988, 28, 219−297.
(54) Maslowsky, E. J. Vibrational Spectra of Organometallic
Compounds; Wiley: New York, 1997.
(55) SAINT, version 5.0; Bruker Analytical X-ray Systems: Madison,
WI, 1997.
(56) Sheldrick, G. M. SADABS: empirical absorption program;
University of Gottingen: Gottingen, Germany, 1996.
̈
̈
(57) Sheldrick, G. M. SHELXL-97: a program for crystal structure
determination; University of Gottingen: Gottingen, Germany, 1997.
̈
̈
(58) Perdew, J. P.; Burke, K.; Ernzerhof, M. Phys. Rev. Lett. 1996, 77,
3865−3868.
(59) Frisch, M. J.et al. Gaussian03, revision B.03; Gaussian, Inc.:
Pittsburgh, PA, 2003. See the Supporting Information for the full
reference.
(60) Vetere, V.; Adamo, C.; Maldivi, P. Chem. Phys. Lett. 2000, 325,
99−105.
́
(61) Graciani, J.; Marquez, A. M.; Plata, J. J.; Ortega, Y.; Hernandez,
N. C.; Meyer, A.; Zicovich-Wilson, C. M.; Sanz, J. F. J. Chem. Theory
Comput. 2011, 7, 56−65.
(62) Zahn, S.; Kirchner, B. J. Phys. Chem. A 2008, 112, 8430−8435.
1953
dx.doi.org/10.1021/ic3021639 | Inorg. Chem. 2013, 52, 1942−1953