Cyclometalated organoplatinum(ii) complexes: First example of a monodentate benzo[h]quinolyl ligand and a complex with bridging bis(diphenylphosphino) ethane

Article abstract of DOI:10.1039/c0dt00855a

The cyclometalated complexes [Pt(ppy)R(SMe₂)] or [Pt(bhq)R(SMe₂)], where ppyH = 2-phenylpyridine, bhqH = benzo[h]quinoline and R = methyl or p-tolyl, react with bis(diphenylphosphino) ethane, dppe, in a 1:1 ratio to give the corresponding complexes [Pt(κ¹-C-ppy)R(dppe)] or [Pt(κ¹-C-bhq)R(dppe)] , in which the ppy or bhq ligands are monodentate and dppe is chelating. The similar reaction in a 2:1 ratio gives the binuclear complexes [{Pt(ppy)R} ₂(μ-dppe)] or [{Pt(bhq)R}₂(μ-dppe)], in which the dppe ligands are in the unusual bridging bidentate bonding mode.

Full text of DOI:10.1039/c0dt00855a

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Cyclometalated organoplatinum(II) complexes: first example of a
monodentate benzo[h]quinolyl ligand and a complex with bridging
bis(diphenylphosphino)ethane†
Mohsen Golbon Haghighi,a Mehdi Rashidi,‡a,c S. Masoud Nabavizadeh,a Sirous Jamalib and
Richard J. Puddephatt*c
Received 16th July 2010, Accepted 21st September 2010
DOI: 10.1039/c0dt00855a
The cyclometalated complexes [Pt(ppy)R(SMe2)] or [Pt(bhq)R(SMe2)], where ppyH = 2-phenylpyridine,
bhqH = benzo[h]quinoline and R = methyl or p-tolyl, react with bis(diphenylphosphino)ethane, dppe, in
1
1
a 1 : 1 ratio to give the corresponding complexes [Pt(k -C-ppy)R(dppe)] or [Pt(k -C-bhq)R(dppe)], in
which the ppy or bhq ligands are monodentate and dppe is chelating. The similar reaction in a 2 : 1 ratio
gives the binuclear complexes [{Pt(ppy)R}2(m-dppe)] or [{Pt(bhq)R}2(m-dppe)], in which the dppe
ligands are in the unusual bridging bidentate bonding mode.
Introduction
We and many others have been interested in the assembly of cy-
clometalated organoplatinum(II) complexes to form more complex
structures for potential applications in molecular materials.1–3 In
particular, the reaction of the complexes A (Scheme 1, R = methyl
or aryl)1,4 with diphosphine ligands in a 1 : 1 molar ratio can give
either B (PP = Ph2PCH2PPh2, dppm) or C (PP = [(Ph2PC5H4)2Fe],
dppf).1 In these complexes, the platinum(II) center remains 4-
coordinate with square planar stereochemistry, but there is a
competition between chelation by the diphosphine ligand or the
C,N-donor ligand derived from 2-phenylpyridine. Complex B has
a free phosphine donor while C has a free pyridyl group. In either
case, reaction in a 2 : 1 molar ratio gives the bridged binuclear
complexes D (Scheme 1).1
Based on the above observations, it was not obvious if complexes
of type C would be formed irreversibly by fast ring closing
on reaction of A with strongly chelating diphosphines such as
bis(diphenylphosphino)ethane, dppe,5 or if it might still be possible
to prepare the bridged binuclear complexes of type D (Scheme 1).1
The ligand dppe may often act as a bridging ligand with coinage
metals having linear or trigonal stereochemistry, or in transition
metal complexes, especially those containing metal-metal bonds.6–9
However, the tendency for chelation of dppe is very strong in
square planar complexes and there are few examples of bridging
dppe (Scheme 2).10,11 It is noteworthy that all contain strongly
bound tridentate pincer ligands which leave only one potential
coordination site for the diphosphine ligand, so that chelation of
dppe is not possible.
Scheme 1 Cyclometalated complexes with diphosphine ligands.
of derivatives of type C and D. The complexes of type D are
unusual examples of square planar complexes with bridging dppe
ligands.
This article reports reactions of cyclometalated complexes of
type A (Scheme 1) with the ligand dppe, including characterization
Results and discussion
The new chemistry is shown in Scheme 3. The com-
plexes [PtMe(ppy)(SMe2)], ppyH = 2-phenylpyridine, 1a, and
[PtMe(bhq)(SMe2)], 2a, bhqH = benzo[h]quinoline, have been
prepared previously by reaction of [Pt2Me4(m-SMe2)2] with ppyH
or bhqH and used in situ for further synthesis.1a,4 In the
present study these compounds, and the known precursors
[Pt(p-MeC6H4)(ppy)(SMe2)], 1b, [Pt(p-MeC6H4)(bhq)(SMe2)], 2b,
were isolated as pure solids.1,4,12 They are air-stable solids and
complex 1b was structurally characterized (Fig. 1).
aDepartment of Chemistry, Faculty of Sciences, Shiraz University, Shiraz,
71454, Iran
bDepartment of Chemistry, Persian Gulf University, Bushehr, 75169, Iran
cDepartment of Chemistry, University of Western Ontario, London, Ontario,
Canada, N6A 5B7. E-mail: pudd@uwo.ca; Fax: +1 519 661 302298; Tel: +1
519 661 2111/679 2111
† CCDC reference numbers 784480–784482. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c0dt00855a
‡ On sabbatical leave from Shiraz University, Iran.
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Scheme 3 Synthesis of complexes 1–6.
Scheme 2 Platinum complexes with bridging dppe ligands.
The complex [Pt(p-MeC6H4)(ppy)(SMe2)], 1b, has square pla-
nar stereochemistry at platinum, with the greatest distortion
associated with the constraints of the chelate Pt(ppy) ring. The
p-tolyl group lies roughly orthogonal to the square plane and to
the ppy ligand, but the two Pt–C distances are approximately equal
(Fig. 1).
Fig. 1 A view of the structure of complex 1b. Selected bond parameters
The complex 3a was prepared by reaction of complex 1a with
dppe in a 1 : 1 ratio. It was isolated as a stable colorless solid
(A, ◦): Pt1–C14 2.000(2); Pt1–C3 2.006(2); Pt1–N1 2.118(2); Pt1–S1
˚
2.3572(7); C14–Pt1–C3 93.56(10); C3–Pt1–N1 80.48(9); C14–Pt1–S1
90.66(7); N1–Pt1–S1 95.30(6).
1
which was characterized by its H and 31P NMR spectra. The
methylplatinum resonance appeared in the 1H NMR spectrum as
a triplet, evidently because the cis and trans coupling constants
3
to phosphorus are equal with JPH = 7 Hz (Fig. 2a). The non-
appropriate precursor complex 1b and 2b (Scheme 3). Attempts to
prepare the complex [PtMe(h -bhq)(dppe)], 4a, in an analogous
1
equivalence of the two phosphorus donors was indicated by the
observation of two resonances in the 31P NMR spectrum at d(31P) =
41.4 [1JPtP = 1811 Hz] and 44.1 [1JPtP = 1821 Hz], and the similar
way were unsuccessful. Also, complex 4b was considerably less
stable in solution than 3b and these observations indicate that the
rigid ligand bhq is less favored than the more flexible ppy when
1
magnitudes of the coupling constants JPtP indicates that both
1
are trans to the carbon donor of an aryl group. The phosphorus-
phosphorus coupling constant 2JPP = 2 Hz, is very small and clearly
shows that the phosphorus donors are mutually cis. Finally, the
non-coordination of the pyridyl group is shown by the absence of
coupling 3JPtH to the H6 proton of the pyridyl group. Complexes 3b
and 4b were prepared and characterized in a similar way from the
bound in the h form.
The complexes 5 and 6 were prepared as yellow solids by
reaction of the appropriate precursor complex 1 or 2 with dppe in
a 2 : 1 ratio (Scheme 3). They were characterized by their 1H and
31P NMR spectra, and complexes 5b and 6b were also structurally
1
characterized. The methylplatinum resonance in the H NMR
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Fig. 2 1H NMR spectra (Pt–Me region, CD2Cl2) of: (a) [PtMe(ppy)-
(dppe)], 3a; (b) [Pt2Me2(bhq)2(m-dppe)], 6a.
spectrum of [Pt2Me2(bhq)2(m-dppe)], 6a, is shown in Fig. 2b.
The main resonance appears as a second order A3A¢3XX¢ spin
1
system through coupling between the H and 31P atoms in each
H3CPtPCCPPtCH3 unit. The apparent doublet is separated by
6
3
3J(PH) + J(PH) and is equal to J(PH) because the long range
coupling is zero. There is a broad central peak, typical of cases with
an intermediate value of 3J(PP).13 The central resonance in the 31
P
NMR spectrum (Fig. 3b) appears as a singlet but the satellite
resonances display the coupling 3J(PP) = 47 Hz.
Fig. 4 Views of the structure of complex 5b: (a) the non-centrosymmetric
molecule; (b) the centrosymmetric molecule; (c) two adjacent molecules
showing some aryl-aryl interactions and a dichloromethane solvate
molecule. Selected bond parameters (A, ◦): Pt1–C1 2.012(3); Pt1–C62
˚
2.041(3); Pt1–N2 2.110(2); Pt1–P1 2.3206(7); Pt2–C33 2.009(3); Pt2–C22
2.033(3); Pt2–N1 2.122(2); Pt2–P2 2.3190(7); Pt3–C70 2.015(3); Pt3–C83
2.045(3); Pt3–N3 2.124(2); Pt3–P3 2.3106(7); C62–Pt1–N2 79.83(10);
C22–Pt2–N1 79.70(11); C83–Pt3–N3 79.47(10).
31P NMR spectra of: (a) [PtMe(ppy)(dppe)], 3a; (b)
the ppy ligands perfectly parallel to one another. However, the
unsymmetrical molecule has PCCP = 175◦ and the angle between
the mean planes of the ppy ligands is 143◦. Fig. 4c shows two
adjacent molecules, in which secondary bonding occurs through a
series of edge-to-face and vertex-to-face aryl ◊ ◊ ◊ aryl attractions.
The structure of complex 6b is shown in Fig. 5. The molecule is
centrosymmetric (Fig. 5a) and is similar to the centrosymmetric
conformer of complex 5b (Fig. 4b). The main difference between
Fig.
3
[Pt2(p-MeC6H4)2(bhq)2(m-dppe)], 6b, in CD2Cl2.
The structure of complex 6a is shown in Fig. 4. There are
two independent molecules in the unit cell, one less symmetrical
conformer (Fig. 4a) and one having a center of symmetry (Fig.
4b). In the centrosymmetric molecule the dppe ligand has the
ideal anti conformation with dihedral angle PCCP = 180◦ and
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It is well known that the 4-membered Pt(dppm) chelate ring is
strained whereas the 5-membered Pt(dppe) chelate ring is not,14
and so this can rationalize the observation of isomer I when
P–P = dppm, even though platinum(II) is a soft metal center
which normally favors phosphorus over nitrogen coordination.15
It should also be noted that the chelate Pt(bhq) is expected to be
relatively favoured compared to the chelate Pt(ppy) ring, based on
the fact that bhq is more rigid. Several monodentate ppy complexes
are known, including I (Scheme 4, C–N = ppy, P–P = dppf, R =
Me),1a but we are not aware of any precedents for the monodentate
form of bhq which is established for complex 4b (Scheme 3).1–3
There is a strong analogy to the coordination chemistry of 2,2¢-
bipyridine (bipy) and 1,10-phenanthroline (phen), for which bipy
forms more monodentate complexes than the more rigid ligand
phen.16
1
The lowest energy structures of the complexes [PtPh(k -C-
1
bhq)(dppe)] and [PtPh(k -C-ppy)(dppe)], as calculated by Density
Functional Theory (DFT), are shown in Fig. 6.17 In the complex
1
[PtPh(k -C-bhq)(dppe)], the nitrogen donor is held close to the
˚
platinum centre (Pt..N = 2.70 A, Fig. 6a), very close to the distances
observed in monodentate phen complexes,16 as required by the
rigid bhq skeleton. The Pt..N interaction appears to be weakly
antibonding in nature, with the HOMO having the character of the
antibonding combination of filled platinum 5dz2 and nitrogen lone
Fig. 5 Views of the structure of complex 6b: (a) the centrosymmetric
molecule; (b) the packing of molecules through p-stacking of bhq groups.
Selected bond parameters (A, ◦): Pt1–C1 2.010(2); Pt1–C8 2.046(2);
˚
Pt1–N1 2.1318(17); Pt1–P1 2.3106(5); C1–Pt1–C8 88.81(8); C8–Pt1–N1
80.60(7); C1–Pt1–P1 91.79(6); N1–Pt1–P1 98.91(5).
1
pair orbitals (Fig. 6c). In the complex [PtPh(k -C-ppy)(dppe)], the
nitrogen donor is anti to platinum and rotation about the pyridyl-
phenyl bond allows the ortho-CH group to twist away from the
platinum centre (Fig. 6b) and the HOMO has weakly antibonding
character with contributions from Pt 5dz2, r (CH) and nitrogen
lone pair orbitals (Fig. 6d).
6b and 5b is in the packing of the molecules. Molecules of complex
6b assemble to give a supramolecular polymer structure through p-
stacking between parallel bhq groups, as shown in Fig. 5b, while
complex 5b does not give p-stacking between the smaller ppy
groups (Fig. 4c).
Conclusions
The cyclometalated platinum(II) complexes derived from 2-
phenylpyridine or benzo[h]quinoline have already given a wide
range of interesting compounds.1–4 The range is now extended to
give rare examples of square planar complexes containing bridging
dppe ligands,10,11 as illustrated by the structures of complexes 5b
and 6b (Scheme 3, Figs. 4 and 5). It is now also possible to
discuss the relative stabilities of the isomers H and I (Scheme
4) as a function of the diphosphine and C,N-donor ligand. For
the complexes studied so far, there is no dependence on whether
R = methyl or aryl or whether C–N = ppy or bhq, but there
is a dependence on the ligand P–P = Ph2PCH2PPh2 (dppm),
(Ph2PC5H4)2Fe (dppf), or Ph2P(CH2)2PPh2 (dppe).1 Only with
dppm is the isomer I favoured, while both dppf and dppe favour
isomer H.
Fig. 6 Views of the DFT calculated structure and the HOMO of (a), (c)
1
1
[PtPh(k -C-bhq)(dppe)] and (b), (d) [PtPh(k -C-ppy)(dppe)].
2
1
1
The calculated structure of [PtPh(k -C,N-ppy)(k -P-dppe)] and
Scheme 4 The potential conversion between isomers [Pt(k -C–N)-
(k -P–P)], H, and [Pt(k -C–N)(k -P–P)], I.
2
2
1
the HOMO, which has mostly platinum 5dz2 character, are shown
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in Fig. 7. The calculated energy is 62 kJ mol-1 higher than for
its isomer shown in Fig. 6b, while the corresponding energy for
spectrometer (in CD2Cl2), with TMS as reference. The 31P NMR
spectra were recorded using either a Bruker Avance DRX 500
spectrometer (in CDCl3), or a Varian Mercury 400 spectrometer
(in CD2Cl2), with 85% H3PO4 as reference. The microanalyses
were performed using a Thermofinigan Flash EA-1112 CHNSO
rapid elemental analyzer. The complexes [PtMe(ppy)(SMe2)],
ppy = 2-phenylpyridine, 1a,4a and [PtMe(bhq)(SMe2)], 1b, bhq =
benzo[h]quinoline,1a,4a have been prepared and used in situ.
However in the present study they were prepared as pure solids
and characterized as described below. Other precursor complexes
[Pt(p-MeC6H4)(ppy)(SMe2)], 1c,1b [Pt(p-MeC6H4)(bhq)(SMe2)],
1d,1b and [PtMe2(m-SMe2)]2,12a were made by the known methods.
2
1
[PtPh(k -C,N-bhq)(k -P-dppe)] is calculated to be 26 kJ mol-1
1
2
higher than for its isomer [PtPh(k -C-bhq)(k -dppe)] shown in
Fig. 6a. Thus, the theory correctly predicts the preferred isomer
1
and also predicts a greater preference for the k -C-isomer for the
pph compared to the bhq complex.
[PtMe(ppy)(SMe2)], 1a
Pure 2-phenylpyridine (100 mL, 0.7 mmol) was added dropwise via
syringe to a solution of [PtMe2(m-SMe2)]2 (200 mg, 0.35 mmol) in
acetone (20 mL) at room temperature. The solution immediately
turned yellow, and small bubbles formed. The solution was stirred
for 20 h and then the solvent was evaporated from the resulting
solution to give a solid that was washed with cold ether and
acetone and dried under vacuum. Yield 110 mg; 75%, mp = 176 ◦C
2
(decomp). NMR in CDCl3: d(1H) = 1.07 [s, 3H, JPtH = 83 Hz,
MePt]; 2.45 (s, 6H, 3JPtH = 25 Hz, MeS]; 8.90 [d, 1H, 3JPtH = 15 Hz,
6
2
1
Fig. 7 The calculated structure of [PtPh(k -C,N-ppy)(k -P-dppe)] (left,
3JH = 6 Hz, H6 of ppy].
6
5
H
H-atoms omitted for clarity) and the HOMO (right).
[PtMe(bhq)(SMe2)], 2a
Similar calculations for the dppm complexes give the predicted
2
structures shown in Fig. 8, and predict that the complex [PtPh(k -
This was prepared similarly using benzo[h]quinoline. Yield 183
mg; 58%, mp = 185 ◦C (decomp). Anal. Calcd d. for C16H17NPtS:
C, 42.7; H, 3.8; N, 3.1; Found: C, 42.4; H, 3.7; N, 2.9. NMR in
1
C,N-bhq)(k -P-dppm)] (Fig. 8a) is more stable than its isomer
1
2
[PtPh(k -C-bhq)(k -P,P-dppm)] (Fig. 8b) by 46 kJ mol-1, in accord
with experiment.1b
CDCl3: d(1H) = 1.25 [s, 3H, JPtH = 83 Hz, MePt]; 2.56 [s, 6H,
2
6
6
5
3JPtH = 26 Hz, MeS]; 9.14 [d, 1H, 3JPtH = 18 Hz, 3JH = 6 Hz, H6
H
of bhq].
[PtMe(ppy)(dppe)], 3a
Dppe (40 mg, 0.1 mmol) was added to
a solution of
[Pt(Me)(ppy)(SMe2)], 1a, (42 mg, 0.1 mmol) in acetone (20 ml).
The mixture was stirred at room temperature for 20 h. After
removal of the solvent by evaporation, a residue was obtained
which was further purified by repeated washing with ether. The
product, as a white solid, was dried under vacuum. Yield 49 mg;
64%, mp = 195 ◦C (decomp). Anal. Calcd. for C35H35NP2Pt: C,
59.8; H, 4.6; N, 1.8; Found: C, 59.3; H, 4.6; N, 2.1. NMR in
2
1
Fig. 8 The calculated structures of (a) [PtPh(k -C,N-bhq)(k -P-dppm)]
1
2
and (b) [PtPh(k -C-bhq)(k -P,P-dppm)] (H-atoms omitted for clarity).
2
3
CD2Cl2: d(1H) = 0.11 [t, 3H, JPtH = 72 Hz, JPH = 7 Hz, MePt];
3
6
5
1.70 [br, 2H, CH2P]; 2.11 [br, 2H, CH2P]; 8.02 [d, 1H, JH
=
Thus, in these monomeric complexes, there are two potentially
bidentate ligands and one of them must be monodentate because
the platinum(II) centre prefers square-planar stereochemistry.
There is a fine balance such that the complexes with P–P = dppe
and dppf prefer the isomeric form H whereas the complexes with
P–P = dppm prefer the form I.1 Both isomers can react with more
platinum complex precursor to give the unusual diphosphine-
bridged binuclear complexes, even when P–P = dppe.
H
4 Hz, H6 of ppy]; d(31P) = 41.4 [d, 1P, 2JPP = 2 Hz, 1JptP = 1811 Hz,
PtP]; 44.1 [d, 1P, 2JpP = 2 Hz, 1JptP = 1821 Hz, PtP].
The following complexes were made similarly by using the
appropriate starting complex 1b or 2b and dppe:
[Pt(p-MeC6H4)(ppy)(dppe)], 3b
Yield 60%, mp = 224 ◦C (decomp). Anal. Calcd for C44H39NP2Pt:
C, 63.0; H, 4.7; N, 1.7. Found: C, 62.7; H, 4.5; N, 1.5. NMR in
CDCl3: d(1H) = 2.34 [s, 3H, MeC]; 2.58 [br, 2H, CH2P]; 2.68 [br,
Experimental
The 1H NMR spectra were recorded using either a Bruker Avance
DPX 250 spectrometer (in CDCl3), or a Varian Mercury 400
2H, CH2P]; 8.28 [d, 1H, 3JH = 4 Hz, H6 of ppy]; d(31P) = 39.6 [s,
6
5
H
1P, 1JptP = 1786 Hz, PtP]; 40.7 [s, 1P, 1JptP = 1726 Hz, PtP].
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Table 1 Crystal and refinement data for the complexes
Complex
1b
5b·2/3CH2Cl2
6b·2CH2Cl2
Formula
fw
C20H21NPtS
502.53
150(2)
0.71073
Monoclinic
P21/n
9.9851(5)
9.4255(5)
18.8056(11)
90
97.461(3)
90
1754.9(2)
4
1.902
8.113
C62.67H55.33Cl1.33N2P2Pt2
1335.81
150(2)
0.71073
Monoclinic
P21/n
14.4438(5)
33.6884(12)
17.0228(6)
90
105.626(2)
90
7977.0(5)
6
1.668
5.425
22381/0/949
0.0250
C68H58Cl4N2P2Pt2
1497.08
150(2)
0.71073
Monoclinic
P21/n
13.5252(9)
14.6944(10)
15.0201(10)
90
100.079(3)
90
2939.1(3)
2
1.692
5.035
6751/0/353
0.0161
T/K
˚
l/A
cryst. syst.
Space gp.
˚
a/A
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
3
˚
V/A
Z
d(c)/Mg m-3
m/mm-1
data/restr./param
R1 [I > 2s(I)]
wR2 [all data]
4908/0/211
0.0202
0.0386
0.0484
0.0359
[Pt(p-MeC6H4)(bhq)(dppe)], 4b
[Pt2(p-MeC6H4)2(bhq)2(l-dppe)], 6b
Yield 62%, mp = 230 ◦C (decomp). Anal. Calcd for C45H37NP2Pt:
C, 57.4; H, 4.2; N, 1.4; Found: C, 57.5; H, 4.3; N, 1.5. NMR in
CDCl3: d(1H) = 2.14 [s, 3H, MeC]; 2.35 [br, 2H, CH2P]; 2.74 [br,
Yield 47%, mp = 285 ◦C (decomp). Anal. Calcd for C66H54N2P2Pt2:
C, 59.7; H, 4.1; N, 2.1; Found: C, 59.3; H, 3.8; N, 2.0. NMR in
CDCl3: d(1H) = 2.31 [s, 3H, MeC]; 1.79 [br, 4H, CH2P]; 8.08 [d,
3JHH = 2 Hz,3JPtH = 8 Hz, H6 of bhq]; d(31P) = 21.8 [s,3JPP = 21 Hz,
1JPtP = 2059 Hz, 4JptP ª 0 Hz, PtP].
3
2H, CH2P]; 6.02 [br. s, 1H, JPtH = 8 Hz, H1 of bhq]; 8.50 [br. s,
1H,3JPtH = 7.4 Hz, H6 of bhq]; d(31P) = 39.2 [s, 1P, 1JPtP = 1946 Hz,
PtP]; 41.3 [d, 1P, 1JPtP = 1964 Hz, PtP].
X-ray structure determinations
[Pt2Me2(ppy)2(l-dppe)], 5a
Data were collected using a Bruker diffractometer. The frames
were integrated with the Bruker SAINT software package using
a narrow-frame algorithm. Data were corrected for absorption
effects using the multi-scan method (SADABS). The structures
were solved by direct methods and refined using the Bruker
SHELXTL Software Package. Details are given in Table 1.
CCDC-784480–784482 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Dppe (20 mg, 0.05 mmol) was added to a solution of
[Pt(Me)(ppy)(SMe2)], 1a, (43 mg, 0.1 mmol) in acetone (20 ml).
The mixture was stirred at room temperature for 24 h. After
removal of the solvent by evaporation, a yellow residue was
obtained which was further purified by repeated washing with
ether and cold acetone. Yield 34 mg; 30%, mp = 220 ◦C (decomp).
Anal. Calcd. for C50H46N2P2Pt2: C, 53.3; H, 4.1; N, 2.5; Found:
C, 53.6; H, 4.0; N, 2.2. NMR in CDCl3: d(1H) = 0.80 [m, 6H,
3
2JPtH = 79 Hz, JPH = 5 Hz, MePt]; 2.81 [br, 4H, CH2P]; 6.50 [br.
s, 2H,3JPtH = 6 Hz, H1 of ppy]; 7.94 [br. s, 2H, H6 of ppy]; d(31P) =
24.5 [s, 1JptP = 2085 Hz, 3JPP = 44 Hz, 4JptP = 2 Hz, PtP].
The following complexes were made similarly by using the
appropriate precursor complexes 2a, 1b or 2b and dppe:
DFT calculations
Calculations were made using the Amsterdam Density Functional
program based on the Becke–Perdew functional, with first-order
scalar relativistic corrections.17
[Pt2Me2(bhq)2(l-dppe)], 6a
Acknowledgements
Yield 21%, mp = 285 ◦C (decomp). Anal. Calcd. for C54H46N2P2Pt2:
C, 55.2; H, 3.9; N, 2.4; Found: C, 55.5; H, 3.9; N, 2.2. NMR data
in CD2Cl2: d(1H) = 0.85 [m, 6H, 3JPH = 8 Hz, 2JPtH = 83 Hz, MePt];
2.92 [br, 4H, CH2P]; 6.75 [dd, 3JHH = 8 Hz, 4JHH = 5 Hz, H1 of ppy];
d(31P) = 24.4 [s, 3JPP = 47 Hz, 1JptP = 2084 Hz, 4JptP ª 0 Hz, PtP].
RJP thanks the NSERC (Canada) for financial support. MR
thanks the Iran National Science Foundation (Grant No.
87041279) for financial support and Shiraz University for granting
sabbatical leave. We thank Dr G. Popov for expert assistance with
the X-ray structure determinations.
[Pt2(p-MeC6H4)2(ppy)2(l-dppe)], 5b
Notes and references
Yield 35%, mp = 230 ◦C (decomp). Anal. Calcd for C64H54N2P2Pt2:
C, 58.2; H, 4.3; N, 2.2; Found: C, 58.8; H, 4.7; N, 2.6. NMR in
CDCl3: d(1H) = 2.30 [s, 3H, MeC]; 1.60 [br, 4H, CH2P]; 6.47 [br. s,
1 (a) S. Jamali, S. M. Nabavizadeh and M. Rashidi, Inorg. Chem.,
2008, 47, 5441; (b) S. M. Nabavizadeh, M. Golbon Haghighi, A. R.
Esmaeilbeig, F. Raoof, Z. Mandegani, S. Jamali, M. Rashidi and R.
J. Puddephatt, Organometallics, 2010, DOI: 10.1021/om100295q in
press.
2H,3JPtH = 6 Hz, H1 of ppy]; d(31P) = 22.1 [s, 1JPtP = 2000 Hz, 3JPP
20 Hz, 4JptP ª 0 Hz, PtP).
=
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2 (a) M. Albrecht, Chem. Rev., 2010, 110, 576; (b) I. Omae, Coord. Chem.
Rev., 2004, 248, 995; (c) A. J. Canty and G. van Koten, Acc. Chem. Res.,
1995, 28, 406; (d) A. D. Ryabov, Chem. Rev., 1990, 90, 403.
Inorg. Chem., 1992, 31, 3067; (d) J.-L. Xiao and M. Cowie, Can. J.
Chem., 1993, 71, 726; (e) P. W. M. Low, Y. L. Yong, Y. K. Yan, T. S. A.
Hor, S. L. Lam, K. K. Chan, C. Wu, S. C. F. Au-Yeung, Y. S. Wen and
L. K. Liu, Organometallics, 1996, 15, 1369; (f) J. P. Blitz, N. T. Lucas
and M. G. Humphrey, J. Organomet. Chem., 2002, 650, 133; (g) H. V.
Huynh, R. Frohlich and F. E. Hahn, Z. Naturforsch. B, 2003, 58, 359;
(h) A. B. Chaplin, R. Scopelliti and P. J. Dyson, Eur. J. Inorg. Chem.,
2005, 4762; (i) W. Gao, J. Ekstrom, J. Liu, C. Chen, L. Eriksson, L.
Weng, B. Akermark and L. Sun, Inorg. Chem., 2007, 46, 1981; (j) F. I.
Adam, G. Hogarth, S. E. Kabir and D. Richards, C. R. Chim., 2008,
11, 890; (k) J.-J. Li, T. Duan, Q.-F. Zhang and W. H. Leung, Chem.
Lett., 2009, 38, 506.
3 (a) S. K. Yen, D. J. Young, H. V. Huynh, L. L. Koh and T. S. A. Hor,
Chem. Commun., 2009, 6831; (b) A. A. Rachford and F. N. Castellano,
Inorg. Chem., 2009, 48, 10865; (c) M. Ghedini, T. Pugliese, M. La
Deda, N. Godbert, I. Aiello, M. Amati, S. Belviso, L. Lelj, G. Accorsi
and F. Barigelletti, Dalton Trans., 2008, 4303; (d) C.-K. Koo, K.-L.
Wong, K.-C. Lau, W.-Y. Wong and M. H.-W. Lam, Chem.–Eur. J.,
2009, 15, 7689; (e) N. Ghavale, A. Wadawale, S. Dey and V. K. Jain,
J. Organomet. Chem., 2010, 695, 1237; (f) T. Yagyu, T.; J. Ohashi
and M. Maeda, Organometallics, 2007, 26, 2383; (g) T. Calvet, M.
Crespo, M. Font-Bardia, K. Gomez, G. Gonzalez and M. Martinez,
Organometallics, 2009, 28, 5096; (h) S.-Y. Chang, Y.-M. Cheng, Y. Chi,
Y.-C. Lin, C.-M. Jiang, G.-H. Lee and P.-T. Chou, Dalton Trans., 2008,
6901.
4 (a) J. S. Owen, J. A. Labinger and J. E. Bercaw, J. Am. Chem. Soc., 2004,
126, 8247; (b) C. Anderson, M. Crespo, J. Morris and J. M. Tanski, J.
Organomet. Chem., 2006, 691, 5635.
5 R. Romeo, L. M. Scolaro, M. R. Plutino and A. Del Zotto, Transition
Met. Chem., 1998, 23, 789.
6 (a) R. Castro, J. Romero, J. A. Garcia-Vasquez, A. Sousa, Y. D. Chang
and J. Zubieta, Inorg. Chim. Acta, 1996, 245, 119; (b) L. Song, P. Lin,
Z.-H. Li, J.-R. Li, S.-W. Du and X.-T. Wu, Polyhedron, 2007, 26, 1199.
7 (a) C. W. Liu, B. Sarkar, B.-J. Liaw, Y.-W. Lin, T. S. Lobana and J.-C.
Wang, J. Organomet. Chem., 2009, 694, 2134; (b) Effendy, F. Marchetti,
C. Pettinari, R. Pettinari, B. W. Skelton and A. H. White, Inorg. Chim.
Acta, 2007, 360, 1388.
10 (a) A. Zucca, G. L. Petretto, S. Stoccoro, M. A. Cinellu, G.
Minghetti, M. Manassero, C. Manassero, L. Male and A. Albinati,
Organometallics, 2006, 25, 2253; (b) L. Adrio, J. M. Antelo, J. M.
Ortigueira, D. Lata, M. T. Pereira, M. Lopez-Torres and J. M. Vila,
Z. Anorg. Allg. Chem., 2007, 633, 1875; (c) W. Sun, H. Zhu and P. M.
Barron, Chem. Mater., 2006, 18, 2602.
11 (a) M. A. Zhuravel, D. S. Glueck, C. D. Incarvito and A. L. Rheingold,
Organometallics, 1999, 18, 4673; (b) J. Martinez, L. Adrio, J. M. Antelo,
J. M. Ortigueira, M. T. Pereira, J. J. Fernandez, A. Fernandez and J. M.
Vila, J. Organomet. Chem., 2006, 691, 2721.
12 (a) J. D. Scott and R. J. Puddephatt, Organometallics, 1983, 2, 1643;
(b) C. Anderson, M. Crespo, G. Ferguson, M. C. Jennings and R. J.
Puddephatt, Organometallics, 1991, 10, 2672; (c) D. Song and S. Wang,
J. Organomet. Chem., 2002, 648, 302.
13 (a) H. Gunther, Angew. Chem., Int. Ed. Engl., 1972, 11, 861; (b) E. W.
Garbisch, J. Chem. Educ., 1968, 45, 480.
8 (a) A. Battisti, O. Bellina, P. Diversi, S. Losi, F. Marchetti and P. Zanello,
Eur. J. Inorg. Chem., 2007, 865; (b) M. M. Artigas, O. Crespo, M. C.
Gimeno, P. G. Jones, A. Laguna and M. D. Villacampa, J. Organomet.
Chem., 1998, 561, 1; (c) S. S. Tang, C. P. Chang, I. J. B. Lin, L. S. Liou
and J. C. Wang, Inorg. Chem., 1997, 36, 2294; (d) M. J. Irwin, J. J. Vittal,
G. P. A. Yap and R. J. Puddephatt, J. Am. Chem. Soc., 1996, 118, 13101.
9 (a) E. M. Moura, M. H. Dickman, H. G. L. Siebald and G. J. Gama,
Polyhedron, 1999, 18, 2899; (b) C. Diaz and E. Araya, Polyhedron, 1997,
16, 1775; (c) K. E. Meyer, D. R. Root, P. E. Fanwick and R. A. Walton,
14 (a) B. Chaudret, B. Delavaux and R. Poilblanc, Coord. Chem. Rev.,
1988, 86, 191; (b) R. J. Puddephatt, Chem. Soc. Rev., 1983, 12, 99.
15 R. G. Pearson, J. Am. Chem. Soc., 1963, 85, 3533.
16 (a) M. Calligaris, E. Zangrando, B. Milani and A. Marson, Eur. J. Inorg.
Chem., 2005, 704; (b) B. Milani, G. Corso, E. Zangrando, L. Randaccio
and G. Mestroni, Eur. J. Inorg. Chem., 1999, 2085.
17 (a) G. Te Velde, F. M. Bickelhaupt, E. J. Baerends, S. van Gisbergen,
C. F. Guerra, J. G. Snijders and T. Ziegler, J. Comput. Chem., 2001, 22,
931; (b) A. Becke, Phys. Rev. A: At., Mol., Opt. Phys., 1988, 38, 3098.
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