Syntheses and characterization of novel bis(phosphoranido)platinum(II) complexes: Reactions of lithium bis(naphth-l,8-diyl-8-oxy)phosphoranide with cis-PtCl2(PRs)2 (R = OPh, OMe, Me)

Article abstract of DOI:10.1002/ejic.200900834

The reactions of cis-PtCl₂(PR₃J₂ (R = OPh, OMe) with 1 equiv. of lithium, phosphoranide generated from, a bis(naphth-1,8diyl-8-oxy)phosphorane lead to the formation of cis-monophosphoranido complexes with high stereospecificity. The reaction of cis-PtCl₂(PMe₃)₂ with 1 equiv. of the lithium, phosphoranide afforded a trans-monophosphoranido complex, exclusively. Hitherto unknown trans-bis(phosphoranido)platinum.(II) complexes were obtained as major products in the reactions of cis-PtCl₂(PR₃)₂ (R = OPh, OMe, Me) with an excess of the lithium phosphoranide. The stereochemistry was confirmed by X-ray structural analysis of the bis(phosphoranido) complex bearing triphenyl phosphites.

Full text of DOI:10.1002/ejic.200900834

FULL PAPER
DOI: 10.1002/ejic.200900834
Syntheses and Characterization of Novel trans-Bis(phosphoranido)platinum(II)
Complexes: Reactions of Lithium Bis(naphth-1,8-diyl-8-oxy)phosphoranide with
cis-PtCl2(PR3)2 (R = OPh, OMe, Me)
Kazumasa Kajiyama,*[a] Issei Sato,[a] Satoru Yamashita,[a] and Takeshi K. Miyamoto[a]
Keywords: Hypervalent compounds / Platinum / Phosphane ligands / Ligand effects
The reactions of cis-PtCl2(PR3)2 (R = OPh, OMe) with 1 equiv.
of lithium phosphoranide generated from a bis(naphth-1,8-
diyl-8-oxy)phosphorane lead to the formation of cis-mono-
phosphoranido complexes with high stereospecificity. The
reaction of cis-PtCl2(PMe3)2 with 1 equiv. of the lithium phos-
phoranide afforded a trans-monophosphoranido complex,
exclusively. Hitherto unknown trans-bis(phosphoranido)-
platinum(II) complexes were obtained as major products in
the reactions of cis-PtCl2(PR3)2 (R = OPh, OMe, Me) with an
excess of the lithium phosphoranide. The stereochemistry
was confirmed by X-ray structural analysis of the bis(phos-
phoranido) complex bearing triphenyl phosphites.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
planar complexes bearing two phosphoranide ligands
(Scheme 1).[8] Consequently, the reactions of phosphoran-
ide 2 with cis-PtCl2(PR3)2 (4) (R = OPh, OMe, Me), in
which the phosphane ligands are monodentate and not
fixed cis, were examined. As a result, not only cis- and/
or trans-monophosphoranidoplatinum(II) complexes 5, but
also unprecedented trans-bis(phosphoranido)platinum(II)
complexes 6 were obtained. Herein, we report on the syn-
theses and characterization of complexes 5 and 6. Also pre-
sented is the X-ray structure of triphenyl phosphite complex
6a.
Introduction
A wide variety of ligand-substitution reactions of square-
planar complexes have been investigated and mechanistic
aspects have been well established.[1] Although hyperval-
ent[2] 10–P–4[3] phosphoranides are capable of behaving as
nucleophiles,[4] the stereochemical course of these reactions
with square-planar complexes has been investigated to a
lesser extent. Among reports on phosphoranido com-
plexes,[5,6] there have only been a few on reactions with
square-planar d8 group 10 metal dihalides of which the
phosphoranides remained intact.[6] The geometry of the re-
sulting monophosphoranido complex was the same as that
of the metal dihalide starting material. Furthermore, the
formation of bis(phosphoranido) complexes was sup-
pressed, although an unstable bis(phosphoranido)palladi-
um(II) complex speculated from 31P NMR analysis had
been reported.[7] A significant factor in the synthesis and
stereochemistry of phosphoranido complexes has been the
steric demand of the phosphoranide ligand. From this as-
pect, it could be anticipated that the compact lithium
bis(naphth-1,8-diyl-8-oxy)phosphoranide 2 generated from
P–H phosphorane 1 would be suitable for the synthesis of
these complexes.[8,9]
Scheme 1. Syntheses of cis-bis(phosphoranido) complexes 3.
Results and Discussion
Recently, we reported that the reaction of one or two
equiv. of phosphoranide 2 with MCl2(dmpe) (M = Pd, Pt)
gave rise to cis-bis(phosphoranido)palladium(II) and -plati-
num(II) complexes 3, the first fully characterized square-
Syntheses and Spectroscopic Properties
Addition of 1 equiv. of lithium phosphoranide 2 to a sus-
pension of cis-PtCl2(PR3)2 (4) in THF resulted in the ex-
clusive formation of monophosphoranido complexes 5,
which could be purified with silica gel chromatography
(Scheme 2, Table 1). While this result is expected in light of
the reaction stoichiometry, it is in contrast with the direct
and exclusive formation of the bis(phosphoranido) com-
[a] Department of Chemistry, School of Science, Kitasato Univer-
sity,
1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan
Fax: +81-42-778-9953
E-mail: kajiyama@sci.kitasato-u.ac.jp
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200900834.
5516
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 5516–5521

Novel trans-Bis(phosphoranido)platinum(II) Complexes
plexes 3.[8] The reaction of the phosphoranide 2 with the
phosphite complexes 4a,b afforded cis-5a,b with high
stereospecificity. By contrast, the reaction with the PMe3
complex 4c gave trans-5c, exclusively.
Scheme 2. Syntheses of monophosphoranido complexes 5.
Table 1. The yields and cis/trans ratio of the complexes 5, and cone
angle of PR3.
[b]
Complex
R
Yield [%]
cis/trans[a]
Cone angle of PR3
5a
5b
5c
OPh
OMe
Me
64
71
61
91:9
91:9
Ͻ1:Ͼ99
128°
107°
118°
[a] Determined by 1H NMR (CDCl3) spectroscopic analysis. [b]
Determined for Ni(CO)3PR3.
Figure 1. 31P{1H} NMR spectrum (162 MHz) of 5a in CDCl3. (a)
Phosphane region. (b) Phosphoranide region for cis-5a.
In the 31P NMR spectra, the resonances for cis-5 ap-
peared as three doublets of doublets due to low symmetry
(Figure 1), while A2X and A2B spin systems could be as-
signed to the signals for the C2 symmetric trans-5a,b and 5c
(Figure 2), respectively. The 1JP,Pt value for the phosphoran-
ide P atom in trans-5 decreases as the π-acidity of the phos-
phane increases (or the σ donor ability of the phosphane
decreases), where the order is P(OAr)3 Ͼ P(OR)3 Ͼ PR3
(Table 2). The reverse trend in the case of cis-5 may be
caused by the distortion of the structure of cis-5a in which
the triphenyl phosphite ligand is also a bulky ligand. The
1JP,Pt value for the phosphoranide P atom in cis-5 is lower
than that in trans-5, which must be a consequence reflecting
the larger trans influence of the phosphite ligand compared
with that of the chloride.[10]
Figure 2. 31P{1H} NMR spectrum (162 MHz) of trans-5c in
CDCl3.
One might expect that the geometry of complex 5 would gen atoms of the phosphite ligands can be excluded since
be partially dependent on the steric demands of the phos- the cis/trans ratio of 5a did not change by the addition of
phane ligands, whose cone angles have been determined in 12-crown-4. The cis and trans-5a,b could not be separated
the case of Ni(CO)3PR3 (Table 1).[11] However, the cis/trans with silica gel chromatography or recrystallization. These
ratio of complex 5 is inconsistent with the trend in steric results might infer that the cis/trans ratio of complexes 5
bulk. The ratio did not significantly vary with reaction time, is dependent on their thermodynamic stabilities although
and the possible effect of a lithium bridge between the oxy- kinetic control can not be denied.
Table 2. 31P{1H} NMR spectroscopic data of the complexes 5 in CDCl3.
Phosphane(t)[a]
δp [ppm] JP,P [Hz]
Phosphane(c)[b]
δp [ppm]
Phosphoranide
δp [ppm]
2
Complex
1JP,Pt [Hz]
2JP,P [Hz] 1JP,Pt [Hz]
51.3, 9.8 6592
43.9, 17.1 6262
2JP,P [Hz]
1JP,Pt [Hz]
cis-5a
cis-5b
83.3
102.8
1047, 51.3 3396
981, 44.0
67.4
83.4
–8.5
–2.2
1045, 9.8
981, 17.1
3508
3374
3552
trans-5a
trans-5b
trans-5c
80.8
100.6
–15.7
24.4
29.3
31.7
4962
4539
2563
–45.2
–44.5
–43.5
24.4
29.3
31.7
4756
4988
5378
[a] The phosphane(t) coordinating trans to the phosphoranide ligand. [b] Phosphane(c) coordinating cis to the phosphoranide ligand.
Eur. J. Inorg. Chem. 2009, 5516–5521
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5517

K. Kajiyama, I. Sato, S. Yamashita, T. K. Miyamoto
Table 3. 31P{1H} NMR spectroscopic data of trans-bis(phosphoranido) complexes 6 in CDCl3.
FULL PAPER
Major isomer
Phosphane
Minor isomer
Phosphane
Phosphoranide[a]
Phosphoranide[a]
2JP,P [Hz] 1JP,Pt [Hz] δp [ppm] 1JP,Pt [Hz]
Complex δp [ppm]
2JP,P [Hz] 1JP,Pt [Hz] δp [ppm] 1JP,Pt [Hz]
δp [ppm]
6a
6b
6c
80.1
101.1
–27.3
51.3
51.3
48.8
5012
4888
2827
–29.7
–25.4
–35.5
2932
3005
3318
100.8
–28.0
51.3
48.8
4810
2822
–24.4
–35.0
3040
3323
2
[a] The JP,P values for the phosphoranide are omitted.
The reactions of 4 with three equiv. of 2 afforded the
corresponding trans-bis(phosphoranido)platinum(II) com-
plexes 6 as the major products (Scheme 3, Table 3). The ex-
tremely high stereoselectivity in the formation of complex
6a probably reflects the bulkiness of the phosphoranide li-
gand. Thus, when the phosphane ligand was the large PPh3
(with a cone angle of 145°[11]), the generation of the corre-
sponding bis(phosphoranido) complex 6 could not be ob-
served.[12] The 31P NMR spectra of the diastereomeric mix-
tures showed two pairs of triplets in contrast with the
AAЈXXЈ spin system for cis-disposed bis(phosphoranido)
complex 3.[8] The 31P NMR spectrum of meso-6a, in which
the relative stereochemistry at the two pentacoordinate
phosphorus atoms is RS(SR),[13] is shown in Figure 3. Sim-
1
ilar to the case of trans-5, the JP,Pt value for the phos-
phoranide diminishes as the π-acidity of the phosphane li-
gand increases (Table 3).
Figure 3. 31P{1H} NMR spectrum (162 MHz) of meso-6a in
CDCl3. (a) Phosphane region. (b) Phosphoranide region.
Scheme 3. Syntheses of trans-bis(phosphoranido) complexes 6.
Crystal Structure
The isolation of meso isomer of 6a and the dia-
stereomeric mixtures of 6b could be achieved by silica gel
The crystal structure of complex 6a could be elucidated
chromatography (CH2Cl2/acetone, 20:1) in 64% and 75% by X-ray structural analysis (Figure 4). The geometry
(de 50%) yield, respectively. On the other hand, the dia- around the platinum atom is an ideal square-planar struc-
stereomeric mixtures of 6c was isolated by purification with ture. The P–Pt bond length of 2.398(2) Å for the phos-
recrystallization in 46% yield (de 40%), since the complex phoranide P atom is slightly longer than that [2.382(2),
6c decomposed on silica gel. The complexes 6 are stable 2.371(2) Å] of cis complex 3B.[8] This implies that the strong
in the air or even in refluxing toluene. However, they are π-acidity of the phosphoranide ligand weakens the trans
consumed entirely in xylene at 150 °C within 8 h to give bond in 6a. The geometry around the hypervalent phospho-
several unidentified products, while the cis-bis(phosphoran- rus atom is a trigonal bipyramidal (TBP) structure with two
ido) complex 3 was stable under the same conditions. The oxygen atoms in the apical positions. Similarly to complex
relative instability of trans complex 6 compared to cis-3 can 3, the equatorial C–P–C angle of 105.3° is much smaller
be explained by the simultaneous interaction of one dπ or- than the ideal value (120°), while the sum of the equatorial
bital on platinum with the σ*orbital on phosphorus of two angles is 360° and the apical O–P–O angle is 180°, which
phosphoranide ligands in addition to the absence of sta- are ideal values for TBP structures. Distortion of the TBP
bility gained by chelation. It has been indicated that the geometry of most phosphoranes is along the Berry pseudo-
electron density on the central atom of pentacoordinate het- rotation coordinate or the turnstile coordinate.[5a,9b,14]
eroatom compounds is lessened since it bears a hypervalent However, this rule is not necessarily applied to the met-
bond, in which the electrons are delocalized into the apical alated phosphoranes.[6a,8] The TBP geometry of complex 6a
substituents.[2] This is consistent with the phosphoranide li- does not distort along either permutation mechanism. The
gand acting as π acid.[5a,5c]
equatorial C–P–C angle of complex 6a is slightly larger
5518
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 5516–5521

Novel trans-Bis(phosphoranido)platinum(II) Complexes
Me4Si or from residual chloroform (δ = 7.26). 31P NMR chemical
shifts (δ) are given in ppm downfield from external 85% H3PO4.
Elemental analyses were performed with a Perkin–Elmer 2400
CHN elemental analyzer.
than that of complex 3B (101.0°, 103.9°),[8] probably due
to the trans arrangement of the two bulky phosphoranide
ligands.
General Procedure for the Preparation of cis-PtCl2(PR3)2 (4): To a
solution of PtCl2(COD) (1.00 g, 2.67 mmol) in benzene (10 mL)
was added 2 equiv. of phosphane. After the reaction mixture was
stirred for 1 h at room temperature, the resulting white crystals
were filtered and washed with benzene. 4a: yield 2.32 g, 98%. 4b:
yield 1.18 g, 86%. 4c: yield 1.07 g, 96%. The 31P NMR spectro-
scopic data of the complexes 4 [R = OPh (4a),[16] OMe (4b),[17] Me
(4c)][18] agreed with the literature data.
General Procedure for the Syntheses of PtCl{P(C10H6O)2}(PR3)2
(5): To a solution of 1 (200 mg, 0.632 mmol) in THF (30 mL) was
added tBuLi (1.50  n-pentane solution, 0.43 mL, 0.65 mmol) at
–78 °C. After removal of the cooling bath, the solution was stirred
at room temperature for 10 min and then transferred to a suspen-
sion of 1 equiv. of cis-PtCl2(PR3)2 (4) in THF (100 mL) at –78 °C.
The reaction mixture was stirred at room temperature for 2 h and
then the solvents were removed under reduced pressure. Purifica-
tion of the residue was carried out by silica gel column chromatog-
raphy with CH2Cl2/acetone (20:1) as eluent. 1H NMR spectro-
scopic data of trans-5a,b could not be assigned entirely due to the
presence of these impurities.
Figure 4. The ORTEP drawing of 6a showing the thermal ellipsoids
at the 30% probability level. All hydrogen atoms are omitted for
clarity. Selected bond lengths [Å] and angles [°]: P1–O1 1.813(2),
P1–O2 1.815(2), P1–Pt1 2.398(2), P1–C1 1.829(3), P1–C11
1.832(4), P2–Pt1 2.275(2); O1–P1–O2 179.58(12), Pt1–P1–C1
129.35(13), C1–P1–C11 105.30(17), C11–P1–Pt1 125.35(10), O1–
P1–Pt1 90.16(8), O1–P1–C1 87.58(14), O1–P1–C11 92.16(15), O2–
P1–Pt1 90.24(9), O2–P1–C1 92.09(14), O2–P1–C11 87.69(16), P1–
Pt1–P2 86.53(3).
5a: (R = OPh, cis:trans, 91:9): Yellow powder; yield 470 mg, 64%;
m.p. 133 °C (dec.). C56H42ClO8P3Pt (1166.43): calcd. C 57.66, H
1
3.64; found C 57.82, H 3.73. H NMR (CDCl3, 400 MHz): cis iso-
mer δ = 7.99–7.92 (m, 2 H, Naph), 7.67 (dd, JH,H = 8.1, 2.7 Hz, 1
H, Naph), 7.41–7.33 (m, 4 H, Naph), 7.17–7.01 (m, 25 H, Naph
and Ph), 6.98 (d, JH,H = 8.1 Hz, 1 H, Naph), 6.88–6.84 (m, 8 H,
Naph and Ph), 6.73 (d, JH,H = 7.6 Hz, 1 H, Naph) ppm; trans iso-
mer: δ = 7.85 (dd, JH,H = 7.3, JH,P = 11.5 Hz, 2 H, Naph), 7.52
(dd, JH,H = 8.1, 2.7 Hz, 2 H, Naph), 7.41–7.33 (m, 4 H, Naph),
7.17–6.84 (m, 32 H, Naph and Ph), 6.48 (d, JH,H = 7.6 Hz, 2 H,
Naph) ppm. 31P{1H} NMR (CDCl3, 162 MHz): cis isomer: δ =
83.3 [dd, JP,P = 1047, 51.3, JP,Pt = 3396 Hz, P(OPh)3], 67.4 [dd, JP,P
= 51.3, 9.8, JP,Pt = 6592 Hz, P(OPh)3], –8.5 [dd, JP,P = 1045, 9.8,
Conclusions
The reaction of 1 equiv. of lithium phosphoranide 2 with
cis-PtCl2(PR3)2 (4) (R = OPh, OMe, Me) gave cis and trans-
monophosphoranido complexes 5, and it is in contrast with
the formation of the cis-bis(phosphoranido) complexes 3.
We were able to synthesize trans-bis(phosphoranido)plati-
num(II) complexes 6, the first square-planar complex with
two phosphoranide ligands in a trans arrangement, from
cis-PtCl2(PR3)2 (4) (R = OPh, OMe, Me) and an excess of
the lithium phosphoranide 2. These structural features
could be verified by the X-ray structural analysis of com-
plex 6a bearing triphenyl phosphites. The trans complexes
6 were thermally unstable relative to the cis complexes 3.
Mechanistic examinations are currently underway and the
results will be described in due course.
JP,Pt = 3508 Hz, P(C10H6O)2] ppm; trans isomer: δ = 80.8 [d, JP,P
24.4, JP,Pt = 4962 Hz, P(OPh)3], –45.2 [t, JP,P = 24.4, JP,Pt
=
=
1
4756 Hz, P(C10H6O)2] ppm.
5b: (R = OMe, cis:trans, 91:9): Yellow powder; yield 356 mg, 71%;
m.p. 164 °C (dec.). C26H30ClO8P3Pt (794.00): calcd. C 39.33, H
1
3.81; found C 39.25, H 3.84. H NMR (CDCl3, 400 MHz): cis iso-
mer: δ = 7.95 (dd, JH,H = 6.8, JH,P = 10.7 Hz, 1 H, Naph), 7.89
(dd, JH,H = 7.8, JH,P = 10.7 Hz, 1 H, Naph), 7.67–7.63 (m, 2 H,
Naph), 7.42–7.29 (m, 4 H, Naph), 7.09 (d, JH,H = 7.8 Hz, 2 H,
Naph), 6.80 (d, JH,H = 6.8 Hz, 1 H, Naph), 6.69 (d, JH,H = 7.8 Hz,
1 H, Naph), 3.76 (d, JH,P = 12.7 Hz, 9 H, Me), 3.39 (d, JH,P
=
Experimental Section
13.7 Hz, 9 H, Me) ppm; trans isomer: δ = 7.85–7.82 (m, 2 H,
Naph), 7.61–7.58 (m, 2 H, Naph), 7.42–7.08 (m, 6 H, Naph), 6.73
(d, JH,H = 7.8 Hz, 2 H, Naph), 3.43 (d, JH,P = 6.7 Hz, 18 H,
Me) ppm. 31P{1H} NMR (CDCl3, 162 MHz): cis isomer: δ = 102.8
[dd, JP,P = 981, 44.0, JP,Pt = 3552 Hz, P(OMe)3], 83.4 [dd, JP,P
43.9, 17.1, JP,Pt = 6262 Hz, P(OMe)3], –2.2 [dd, JP,P = 981, 17.1,
JP,Pt = 3374 Hz, P(C10H6O)2] ppm; trans isomer: δ = 100.6 [d, JP,P
General: All reagents and solvents were of standard reagent grade
and were used in the syntheses without further purification except
for benzene and THF. All reactions were carried out under a nitro-
gen atmosphere. Benzene and THF used in the syntheses were
freshly distilled from CaH2 and Na-benzophenone, respectively,
and transferred under the positive pressure of nitrogen via a sy-
ringe. Phosphorane 1[8a,9b] and PtCl2(COD)[15] were prepared ac-
cording to published procedures. Column chromatography was per-
formed using Silica Gel 60N (Kanto Chemical Co., Inc., 0.063–
0.210 mm particle size). Melting points were measured with a Yan-
=
= 29.3, JP,Pt = 4539 Hz, P(OMe)3], –44.5 [t, JP,P = 29.3, JP,Pt
4988 Hz, P(C10H6O)2] ppm.
=
trans-5c: (R = Me): Yellow powder; yield 267 mg, 61%; m.p. 255 °C
(dec.). C26H30ClO2P3Pt (698.00): calcd. C 44.74, H 4.34; found C
aco micro melting-point apparatus and are uncorrected. 1H and 31
P
44.43, H 4.32. 1H NMR (CDCl3, 400 MHz): δ = 7.85 (ddd, JH,H
=
NMR spectra were recorded with a JEOL EX-400 spectrometer. 1H
7.1, 3.7, JH.P = 11.0 Hz, 2 H, Naph), 7.67 (dd, JH,H = 8.1, 2.7 Hz,
2 H, Naph), 7.40 (t, JH,H = 8.1 Hz, 2 H, Naph), 7.36–7.32 (m, 2
NMR chemical shifts (δ) are given in ppm downfield from internal
Eur. J. Inorg. Chem. 2009, 5516–5521
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5519

K. Kajiyama, I. Sato, S. Yamashita, T. K. Miyamoto
FULL PAPER
H, Naph), 7.09 (dd, JH,H = 8.3, 1.7 Hz, 2 H, Naph), 6.77 (d, JH,H
= 7.6 Hz, 2 H, Naph), 1.25 (virtual t, JH,P = 3.9 Hz, 18 H,
7.32–7.24 (m, 4 H, Naph), 7.11 (d, JH,H = 8.3 Hz, 4 H, Naph), 6.85
(d, JH,H = 7.3 Hz, 4 H, Naph), 1.06–0.98 (m, 18 H, Me) ppm;
Me) ppm. 31P{1H} NMR (CDCl3, 162 MHz): δ = –15.7 (d, JP,P
=
minor isomer: δ = 7.88–7.84 (m, 4 H, Naph), 7.61 (d, JH,H
8.3 Hz, 4 H, Naph), 7.37 (t, JH,H = 7.8 Hz, 4 H, Naph), 7.32–7.24
(m, 4 H, Naph), 7.03 (d, JH,H = 8.3 Hz, 4 H, Naph), 6.84 (d, JH,H
7.3 Hz, 4 H, Naph), 1.06–0.98 (m, 18 H, Me) ppm. 31P{1H} NMR
(CDCl3, 162 MHz): major isomer: δ = –27.3 (t, JP,P = 48.8, JP,Pt
=
31.7, JP,Pt = 2563 Hz, PMe3), –43.5 [t, JP,P = 31.7, JP,Pt = 5378 Hz,
P(C10H6O)2] ppm.
=
meso-trans-Pt{P(C10H6O)2}2{P(OPh)3}2 (meso-6a): To a solution
of 1 (500 mg, 1.58 mmol) in THF (30 mL) was added tBuLi (1.50 
n-pentane solution, 1.05 mL, 1.58 mmol) at –78 °C. After removal
of the cooling bath, the solution was stirred at room temperature
for 10 min and then transferred to a suspension of 1/3 equiv. of cis-
PtCl2{P(OPh)3}2 (4a) (460 mg, 0.519 mmol) in THF (100 mL) at
–78 °C. The reaction mixture was stirred at room temperature for
2 h and then the solvents were removed under reduced pressure.
Purification of the residue was carried out by silica gel column
chromatography with CH2Cl2 as eluent to give meso-6a as a yellow
powder; yield 480 mg, 64%; m.p. 245 °C (dec.). C76H54O10P4Pt
(1446.27): calcd. C 63.11, H 3.77; found C 63.27, H 3.92. 1H NMR
(CDCl3, 400 MHz): δ = 7.67 (dd, JH,H = 6.6, JH,P = 11.7 Hz, 4 H,
Naph), 7.29 (d, JH,H = 7.6 Hz, 4 H, Naph), 7.08–6.99 (m, 26 H,
Naph and Ph), 6.85 (d, JH,H = 8.3 Hz, 4 H, Naph), 6.75 (d, JH,H
= 7.3 Hz, 12 H, Ph), 6.01 (d, JH,H = 7.6 Hz, 4 H, Naph) ppm.
=
2827 Hz, PMe3), –35.5 [t, JP,P = 48.8, JP,Pt = 3318 Hz, P(C10H6-
O)2] ppm; minor isomer: δ –28.0 (t, JP,P = 48.8, JP,Pt = 2822 Hz,
PMe3), –35.0 [t, JP,P = 48.8, JP,Pt = 3323 Hz, P(C10H6O)2] ppm.
X-ray Structure Determination: The diffraction data for the com-
plex meso-6a were measured with a Rigaku AFC-7R diffractometer
using graphite-monochromated Mo-Kα radiation (λ = 0.71069).
The data were collected at 296 K using MSC/AFC diffractometer
control software. The structure was solved by direct methods using
SIR92.[19] All non-hydrogen atoms were refined anisotropically. All
hydrogen atoms were refined using a riding model. Crystal data
and structure refinement are summarized in Table 4.
Table 4. Crystal data and structure refinement for meso-6a.
meso-6a
31P{1H} NMR (CDCl3, 162 MHz): δ = 80.1 [t, JP,P = 51.3, JP,Pt
=
Empirical formula
Mr
Crystal system
Space group
C76H54O10P4Pt
1446.24
monoclinic
P21/n
5012 Hz, P(OPh)3], –29.7 [t, JP,P = 51.3, JP,Pt = 2932 Hz, P(C10H6-
O)2] ppm.
trans-Pt{P(C10H6O)2}2{P(OMe)3}2 (6b): To a solution of 1 (1.53 g,
4.84 mmol) in THF (60 mL) was added tBuLi (1.50  n-pentane
solution, 3.30 mL, 4.95 mmol) at –78 °C. After removal of the cool-
ing bath, the solution was stirred at room temperature for 10 min
and then added to a suspension of 1/3 equiv. of cis-PtCl2-
[P(OMe)3]2 (4b) (834 mg, 1.62 mmol) in THF (100 mL) at –78 °C.
The reaction mixture was stirred at room temperature for 2 h and
the solvents were removed under reduced pressure. Purification of
the residue was carried out by silica gel column chromatography
(CH2Cl2/acetone, 20:1) to give the diastereomeric mixture (75:25)
of 6b as a yellow powder; yield 1.31 g, 75%; m.p. 245 °C (dec.).
C46H42O10P4Pt (1073.84): calcd. C 51.45, H 3.95; found C 51.44,
H 3.87. 1H NMR (CDCl3, 400 MHz): major isomer: δ = 7.77–7.73
(m, 4 H, Naph), 7.59 (d, JH,H = 8.3 Hz, 4 H, Naph), 7.38 (t, JH,H
a [Å]
b [Å]
c [Å]
11.530(9)
22.048(7)
12.735(6)
101.75(4)
3169.6(29)
2
β [°]
V [Å3]
Z
Dc [gcm–3]
1.515
23.682
µ(Mo-Kα) [cm–1]
Number of reflections collected
Number of independent reflections (Rint
Number of parameters
R1 [I Ͼ 2σ(I)]
7618
7268 (0.057)
468
0.0318
0.0930
)
wR2 (all data)
GOF
0.953
= 8.1 Hz, 4 H, Naph), 7.34–7.27 (m, 4 H, Naph), 7.10 (d, JH,H
=
8.1 Hz, 4 H, Naph), 6.74 (d, JH,H = 7.3 Hz, 4 H, Naph), 3.01 (t,
JH,P = 6.3 Hz, 18 H, Me) ppm; minor isomer: δ = 7.82–7.78 (m, 4
H, Naph), 7.57 (d, JH,H = 8.3 Hz, 4 H, Naph), 7.34–7.27 (m, 8 H,
Naph), 7.04 (d, JH,H = 8.1 Hz, 4 H, Naph), 6.70 (d, JH,H = 7.6 Hz,
4 H, Naph), 3.03 (t, JH,P = 6.3 Hz, 18 H, Me) ppm. 31P{1H} NMR
CCDC-743272 (for meso-6a) 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.
Supporting Information (see also the footnote on the first page of
this article): NMR spectra of complexes 5, 6, and 3B.
(CDCl3, 162 MHz): major isomer: δ = 101.1 (t, JP,P = 51.3, JP,Pt
=
4888 Hz, PMe3), –25.4 [t, JP,P = 51.3, JP,Pt = 3005 Hz, P(C10H6-
O)2] ppm; minor isomer: δ 100.8 (t, JP,P = 51.3, JP,Pt = 4810 Hz,
PMe3), –24.4 [t, JP,P = 51.3, JP,Pt = 3040 Hz, P(C10H6O)2] ppm.
[1] a) R. J. Cross, Adv. Inorg. Chem. 1989, 34, 219–292; b) M. L.
Tobe, J. Burgess, Inorganic Reaction Mechanisms, Longman,
Essex, UK, 1999; c) J. Cooper, T. Ziegler, Inorg. Chem. 2002,
41, 6614–6622.
[2] K.-y. Akiba, Chemistry of Hypervalent Compounds, Wiley-
VCH, New York, 1999.
[3] C. W. Perkins, J. C. Martin, A. J. Arduengo III, W. Lau, A. Ale-
gria, J. K. Kochi, J. Am. Chem. Soc. 1980, 102, 7753–7759.
[4] The 10–P–4 phosphoranides are also capable of functioning
as electrophiles, see: a) K. Kajiyama, S. Kojima, K.-y. Akiba,
Tetrahedron Lett. 1996, 37, 8409–8412; b) K. Kajiyama, M.
Yoshimune, M. Nakamoto, S. Matsukawa, S. Kojima, K.-y.
Akiba, Org. Lett. 2001, 3, 1873–1875; c) S. Matsukawa, S. Ko-
jima, K. Kajiyama, Y. Yamamoto, K.-y. Akiba, S. Re, S. Na-
gase, J. Am. Chem. Soc. 2002, 124, 13154–13170; d) K. Kaji-
yama, M. Yoshimune, S. Kojima, K.-y. Akiba, Eur. J. Org.
Chem. 2006, 2739–2746.
trans-Pt{P(C10H6O)2}2(PMe3)2 (6c): To a solution of 1 (909 mg,
2.87 mmol) in THF (30 mL) was added tBuLi (1.50  n-pentane
solution, 1.90 mL, 2.85 mmol) at –78 °C. After removal of the cool-
ing bath, the solution was stirred at room temperature for 10 min
and then added to a suspension of 1/3 equiv. of cis-PtCl2(PMe3)2
(4c) (400 mg, 0.957 mmol) in THF (100 mL) at –78 °C. The reac-
tion mixture was stirred at room temperature for 2 h and then the
solvents were removed under reduced pressure. Purification of the
residue was carried out by recrystallization from CH2Cl2/hexane to
give the diastereomeric mixture (70:30) of 6c as an orange powder;
yield 435 mg, 46%; m.p. 228 °C (dec.). C46H42O4P4Pt (977.84):
1
calcd. C 56.50, H 4.34; found C 56.52, H 4.38. H NMR (CDCl3,
400 MHz): major isomer: δ = 7.77–7.73 (m, 4 H, Naph), 7.65 (d,
JH,H = 8.1 Hz, 4 H, Naph), 7.47 (t, JH,H = 7.8 Hz, 4 H, Naph),
5520
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 5516–5521

Novel trans-Bis(phosphoranido)platinum(II) Complexes
[5]
or recrystallization and were obtained as a mixture containing
unidentified products.
Review or accounts: a) C. D. Montgomery, Phosphorus Sulfur
Silicon 1993, 84, 23–34; b) K. B. Dillon, Chem. Rev. 1994, 94,
1441–1456; c) H. Nakazawa, K. Kubo, K. Miyoshi, Bull.
Chem. Soc. Jpn. 2001, 74, 2255–2267.
a) R. Faw, C. D. Montgomery, S. J. Rettig, B. Shurmer, Inorg.
Chem. 1998, 37, 4136–4138; b) K. Toyota, Y. Yamamoto, K.-
y. Akiba, J. Chem. Res. (S) 1999, 386–387.
[13] J. C. Martin, T. M. Balthazor, J. Am. Chem. Soc. 1977, 99, 152–
162.
[14] R. R. Holmes, J. A. Deiters, J. Am. Chem. Soc. 1977, 99, 3318–
3326.
[15] J. X. McDermott, J. F. White, G. M. Whitesides, J. Am. Chem.
Soc. 1976, 98, 6521–6528.
[16] N. Ahmad, E. W. Ainscough, T. A. James, S. D. Robinson, J.
Chem. Soc., Dalton Trans. 1973, 1148–1150.
[17] Q.-B. Bao, T. B. Brill, Inorg. Chem. 1987, 26, 3447–3452.
[18] L. Goggin, P. R. J. Goodfellow, S. R. Haddock, J. R. Knight,
F. J. S. Reed, B. F. Taylor, J. Chem. Soc., Dalton Trans. 1974,
523–533.
[6]
[7]
[8]
I. Tkatchenko, Phosphorus Sulfur Silicon 1983, 18, 311–314.
a) K. Kajiyama, Y. Hirai, T. Otsuka, H. Yuge, T. K. Miyamoto,
Chem. Lett. 2000, 29, 784–785; b) K. Kajiyama, H. Yuge, T. K.
Miyamoto, Phosphorus Sulfur Silicon 2002, 177, 1433–1436.
[9] a) K. Kajiyama, A. Nakamoto, S. Miyazawa, T. K. Miyamoto,
Chem. Lett. 2003, 32, 332–333; b) K. Kajiyama, T. K. Miyam-
oto, K. Sawano, Inorg. Chem. 2006, 45, 502–504.
[10] T. G. Appleton, H. C. Clark, L. E. Manzer, Coord. Chem. Rev.
1973, 10, 335–422.
[11] C. A. Tolman, Chem. Rev. 1977, 77, 313.
[12] The formation of a 1:1 mixture of cis and trans-5 was specu-
lated from 31P NMR analysis. However, the complexes decom-
posed slowly during purification by silica gel chromatography
[19] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi,
M. C. Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr.
1994, 27, 435.
Received: August 24, 2009
Published Online: November 17, 2009
After publication in Early View, a small error in Scheme 1 has
been corrected.
Eur. J. Inorg. Chem. 2009, 5516–5521
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5521