(Diphosphine)platinum(II) Diolate Complexes
Inorganic Chemistry, Vol. 36, No. 25, 1997 5841
probe temperatures were calibrated with methanol as described in the
literature.65 Unless otherwise noted, weighings were accurate to (0.2
mg and volumetric flask measurements to (1%, and syringe measure-
ments to (1-2%. The density of CH2Cl2 at 295 K was taken to be
1.325 g/mL, that of CD2Cl2 to be 1.362 g/mL.66 The latter’s temperature
dependence was assumed to have the same percentage variation as that
of CH2Cl2, which is given by the formula (molar density d for T in
K):67
0.2902
)
d ) 1.3897/(0.25678(1+(1-T/510)
Synthesis of (dppp)Pt(4-methoxy-1,2-butanediolate). The com-
plex was prepared analogously to other (dppp)Pt(diolate) complexes;1
thus, (dppp)Pt(CO3) (179 mg, 269 µmol) and 4-methoxy-1,2-butanediol
(50.9 mg, 420 µmol, 1.56 equiv) were dissolved in CH2Cl2 (15 mL) in
a 25 mL Schlenk flask. The solution was stirred for 2 h under argon,
during which time the solution was bubbled with argon for 1 min every
15 min. At this time, a 31P NMR spectrum showed that the reaction
was only 65% complete, so an additional quantity of 4-methoxy-1,2-
butanediol (14.2 mg, 117 µmol, 2.0 equiv total) was added. After
stirring an additional 2.5 h with periodic bubbling with argon, another
NMR spectrum indicated that the reaction was 97% complete. The
reaction mixture was allowed to stand for another 30 min and then the
volume of the reaction mixture was reduced. The solution was
transferred to a diffusion tube, concentrated to a total volume of 3 mL,
and then layered with ether (25 mL). Diffusion over 48 h yielded white
crystals of (dppp)Pt(4-methoxy-1,2-butanediolate) which were washed
with cold ether (4 × 2 mL) and vacuum dried. The supernatant was
evaporated; the residue was redissolved in a minimum of CH2Cl2 (2
mL) and layered with ether again (20 mL). Diffusion over 72 h at
room temperature yielded a second crop. Total yield was 109 mg,
56%, of spectroscopically pure material. 31P NMR (CD2Cl2): δ -8.48
(d with 195Pt satellites, JPP ) 32 Hz, JPtP ) 3131 Hz), -8.83 (d with
195Pt satellites, JPP ) 32 Hz, JPtP ) 3141 Hz). 1H NMR (CD2Cl2): δ
7.8 (m, 8 H), 7.3 (m, 12 H), 3.75 (m, 1 H, PtOCHCH2CH2OMe), 3.67
(ddd, JHH ) 9.1, 4.0 Hz, JPH ) 4.0 Hz, 1 H, PtOCHAHB), 3.40 (ddd,
JHH ) 9.1, 6.0 Hz, JPH ) 3.0 Hz, 1 H, PtOCHAHB), 3.28 (t, JHH ) 7.4
Hz, 2 H, CH2CH2OMe), 3.19 (s, 3 H, OCH3), 2.4 (m, 4 H, PCH2),
1.95 (m, 2 H, PCH2CH2), 1.74 (d of t, JHH ) 5.8, 7.4 Hz, 2 H, CH2-
OMe). 13C{1H} NMR (CD2Cl2): δ 133.8 (m), 131.0 (m), 128.7 (m),
81.8 (dd, JPC ) 4.7, 2.4 Hz, PtOCA), 80.7 (dd, JPC ) 4.5, 2.6 Hz,
PtOCB), 72.1 (s, CH2OMe), 58.5 (s, OCH3), 35.6 (br s, with Pt satellites,
JPtC ) 22 Hz, CH2CH2OMe), 26.0 (dd, JPC ) 34.5, 7.7 Hz, PACH2),
Figure 6. Design of home-built valved NMR tube cap.
CH3), 26.1 (dd, JPC ) 38.3, 3.8 Hz, JPtC ) 27 Hz, PCAH2), 24.9 (dd,
JPC ) 38.3, 3.6 Hz, JPtC ) 27 Hz, PCBH2), 20.4 (s, JPtC ) 21 Hz,
PCH2CH2).
Synthesis of (dppp)Pt(methyl 2,3-O,O′-diolato-4,6-O-benzylidene-
r-D-glucopyranoside). (dppp)Pt(CO3) (258.6 mg, 387 µmol) and
methyl 4,6-O-benzylidene-R-D-glucopyranoside (234.8 mg, 832 µmol,
2.14 equiv) were dissolved in CH2Cl2 (20 mL) in a 100 mL Schlenk
flask. The flask was partially evacuated and refilled with argon (about
sets of three cycles repeated once per hour) over a 8 h period and then
the solution allowed to stir overnight, at which time a 31P NMR showed
97% conversion to product. The solution was concentrated to 2-3
mL and layered with ether (∼15 mL). The resulting white precipitate
was isolated by centrifugation, washed with ether (2 × 20 mL), and
dried under vacuum to give the desired product (310 mg, 90%),
spectroscopically pure except for a trace of ether (2 mol %). 31P NMR
(CD2Cl2): δ -9.73 (d with 195Pt satellites, JPtP ) 3224 Hz, JPP ) 32
Hz), -10.11 (d with 195Pt satellites, JPtP ) 3170 Hz, JPP ) 32 Hz). 1H
NMR (CD2Cl2): δ 7.9 (m, 8 H), 7.35 (m, 17 H), 5.47 (s, CHPh), 4.77
(d, JHH ) 3.4 Hz, CHOMe), 4.23 (dd, JHH ) 9.7, 4.4 Hz, CHAHB),
4.04 (∼t, JHH ≈ 9.1, PtOCHCHCHOMe), 3.72 (∼t, JHH ≈ 10 Hz,
HAHB), 3.72 (dd, JHH ) 9.5, 3.4 Hz, PtOCHCHOMe), 3.60 (∼ddd,
JHH ≈ 10, 9, 4.4 Hz, CHCH2), 3.50 (∼t, JHH ≈ 9 Hz, CHOCHPh),
3.39 (s, OCH3), 2.4 (br m, 4 H, PCH2), 1.95 (m, 2 H, PCH2CH2).
13C{1H} NMR (CD2Cl2): δ 139.1 (s), 134 (m), 131.2 (m), 128.7 (m),
25.7 (dd, JPC ) 34.0, 7.3 Hz, PBCH2), 20.3 (s, with Pt satellites, JPtC
)
128.3 (s), 126.8 (s), 104.2 (d, JPC ) 4.9 Hz, with Pt satellites, JPtC
)
20 Hz).
56 Hz, PtOCHCHOMe), 101.2 (s, CHPh), 86.3 (dd, JPC ) 4.2, 2.7 Hz,
PtOC), 85.7 (d, JPC ) 2.9 Hz, with Pt satellites, JPtC ) 56 Hz,
PtOCHCHOCHPh), 82.4 (dd, JPC ) 4.0, 2.9 Hz, PtOC), 69.6 (s, [13C:
t, JCH ) 146 Hz], CHCH2), 64.2 (s, [13C: d, JCH ) 146 Hz], CH2),
55.6 (s, [13C: q, JCH ) 140 Hz], OCH3), 25.9 (dd, JPC ) 36.2, 7.3 Hz,
PACH2), 25.8 (dd, JPC ) 35.8, 7.5 Hz, PBCH2), 20.2 (s, with Pt satellites,
JPtC ) 21 Hz, PCH2CH2).
Synthesis of (dppp)Pt(3,3-dimethyl-1,2-butanediolate). This was
prepared analogously to the ethanediolate complex,1 yield 45%.
31P{1H} NMR (CD2Cl2): δ -8.5 (d with Pt satellites, JPP ) 31.4 Hz,
JPtP ) 3096 Hz), -10.6 (d with Pt satellites, JPP ) 31.4 Hz, JPtP
)
3127 Hz). 1H NMR (CD2Cl2) (second-order analysis utilizing the
Bruker Panic program): δ 7.85 (m, 6 H, Ph), 7.81 (m, 2 H, Ph), 7.38
(m, 12 H, Ph), 3.68 (m, JHH ) 10.1, (-)9.1 Hz, JPH ≈ 0 Hz, 1 H,
OCHBHC), 3.59 (m, JHH ) 10.1, 3.8 Hz, JPH ≈ 0 Hz, 1 H, OCHA-t-
Bu), 3.52 (m, JHH ) (-)9.1, 3.8 Hz, JPH ) 8.6, (-)2.2 Hz, 1 H,
OCHBHC), 2.40 (br m, 4 H, PCH2), 1.95 (br m, 2 H, PCH2CH2), 0.82
(s, 9 H, CH3). 13C{1H} NMR (CD2Cl2): δ 134.0 (d, JPC ) 10.1 Hz,
JPtC ) 20 Hz, ortho C), 133.9 (d, JPC ) 10.7 Hz, JPtC obscured, ortho
NMR of (dppp)Pt(Ped).
obtained at higher concentrations than that used in ref 1, permitted
PtC, 40 Hz, for the phenyl-1,2-ethanediolate ipso carbon to be
A
13C{1H} NMR of (dppp)Pt(Ped),
J
determined.
Determination of Effective Density of OPPh3 in CH2Cl2. Tri-
phenylphosphine oxide (178.1 mg) was dissolved in CH2Cl2 (1.1354
g, calculated to be 0.857 mL), which gave exactly 1.00 mL of total
solution in a screw-capped volumetric flask. From this, the effective
volume of the OPPh3 was 0.14 mL, giving an effective density of 1.24-
(9) g/mL.
Titrations of Phenol with OPPh3. In a typical titration, a stock
solution of phenol (19.3 mg, 205 µmol in CD2Cl2 (1.1072 g)) was
prepared in a screw-capped vial equipped with a Mininert Microflex
valve (Kontes), which, based on a total volume of 0.829 mL ((1.1072
+ 0.0193)/1.362, assuming within experimental error that the effective
density of PhOH is equal to that of CD2Cl2 at this low concentration),
corresponded to a phenol concentration of 247 mM. A 10.0 µL aliquot
of this solution was added to CD2Cl2 (0.5827 g, 0.4278 mL) in a screw-
capped NMR tube equipped with a special home-built valve modeled
after the Mininert Microflex valve (Figure 6, see Supporting Information
for design details) to give a 5.7(1) mM solution of phenol. A typical
C), 133.8 (d, JPC ) 10.1 Hz, JPtC obscured, ortho C), 133.4 (d, JPC
)
10.8 Hz, JPtC ) 20 Hz, ortho C), 131.8 (d, JPC ) 58 Hz, ipso C), 131.7
(d, JPC ) 58 Hz, ipso C), 131.6 (d, JPC ) 58 Hz, ipso C), 131.3 (d, JPC
) 58 Hz, ipso C), 130.9 (d, JPC ) 2.8 Hz, para C), 130.9 (d, JPC ) 2.4
Hz, para C), 130.8 (d, JPC ) 2.9 Hz, para C), 130.7 (d, JPC ) 2.8 Hz,
para C), 128.7 (d, JPC ) 10.6 Hz, meta C), 128.6 (d, JPC ) 10.6 Hz,
meta C), 128.4 (d, JPC ) 10.5 Hz, meta C), 128.3 (d, JPC ) 10.7 Hz,
meta C), 92.8 (dd, JPC ) 5.2, 3.4 Hz, OCH), 76.1 (dd, JPC ) 5.0, 3.9
Hz, OCH2), 34.2 (d, JPC ) 3 Hz, JPtC ) 40 Hz, C(CH3)3), 27.6 (s,
(65) Van Geet, A. L. Anal. Chem. 1970, 42, 679-680.
(66) Aldrich Catalog Handbook of Fine Chemicals; Aldrich Chemical Co.,
Milwaukee, WI, 1994-1995.
(67) From the Design Institute for Physical Property Data (DIPPR) file,
American Institute of Chemical Engineers (AIChe) accessed via the
Scientific and Technical Information Network (STN).