A family of platinaoxetanes

Article abstract of DOI:10.1021/om7010479

Treatment of the platinaoxetane [Pt₂(COD)₂(OC ₇H₁₀)Cl]BF₄ (1), prepared from oxo complex [Pt₄(COD)₄(O)₂(Cl)₂](BF ₄)₂ and norbornene, with CP yields platinaoxetane Pt(COD)(OC₇H₁₀) (2) and (COD)PtCl₂. Addition of BF₃ · Et₂O to 2 gives the BF₃ adduct Pt(COD)(C₇H₁₀OBF₃) (3). Treatment of 1 with BF₃ · Et₂O also affords 3 along with [Pt(COD)(μ-Cl)]₂(BF₄)₂. COD displacement from 1 by PEt₃ gives Pt(PEt₃)₂(OC ₇H₁₀) (5) and [Pt(PEt₃MCl)]BF₄. Complex 5 is also available from 2 and PEt₃. Treatment of 5 with BF₃ gives Pt(PEt₃MC₇H₁₀OBF ₃) (6). COD displacement from 3 by PPh₃, bis(diphenylphosphino)ethane (dppe), 4,4′-dimethyl-2,2′-bipyridine (Me2bpy), or 4,4′-di-tert-buty1-2,2′-bipyridine (Bu₂ ^tbpy) yields Pt(PPh₃)₂(C₇H ₁₀OBF₃) (7), Pt(dppe)(C₇H₁₀OBF ₃) (8), Pt(Me₂bpy)(C₇H₁₀OBF ₃) (9), and Pt(Bu₂^tbpy)(C₇H ₁₀OBF₃) (10), respectively. All new complexes have been fully characterized by ¹H, ¹³C, DEPT, ¹H- ¹H COSY, ¹H-¹³C COSY (HMQC), and ¹⁹⁵Pt NMR spectroscopy and elemental analysis. Three complexes (3, 6, 10) were characterized by single-crystal X-ray crystallography.

Full text of DOI:10.1021/om7010479

1
234
Organometallics 2008, 27, 1234–1241
A Family of Platinaoxetanes
Jianguo Wu and Paul R. Sharp*
Department of Chemistry, UniVersity of Missouri-Columbia, Columbia, Missouri 65211
ReceiVed October 18, 2007
Treatment of the platinaoxetane [Pt
Pt (COD) (O) (Cl) ](BF and norbornene, with Cl yields platinaoxetane Pt(COD)(OC
and (COD)PtCl . Addition of BF · Et O to 2 gives the BF adduct Pt(COD)(C ) (3). Treatment
of 1 with BF · Et O also affords 3 along with [Pt(COD)(µ-Cl)] (BF . COD displacement from 1
by PEt gives Pt(PEt (OC 10) (5) and [Pt(PEt (Cl)]BF . Complex 5 is also available from 2 and
PEt . Treatment of 5 with BF gives Pt(PEt (C ) (6). COD displacement from 3 by PPh
bis(diphenylphosphino)ethane (dppe), 4,4′-dimethyl-2,2′-bipyridine (Me bpy), or 4,4′-di-tert-buty-
) (7), Pt(dppe)(C ) (8), Pt(Me
) (10), respectively. All new complexes have been
2 2 7 4
(COD) (OC H10)Cl]BF (1), prepared from oxo complex
-
[
4
4
2
2
4
)
2
7
H10) (2)
2
3
2
3
7 3
H10OBF
3
2
2
4 2
)
3
3
)
2
7
H
3
)
3
4
3
3
3
)
2
7
H
10OBF
3
3
,
2
t
l-2,2′-bipyridine (Bu
2
bpy) yields Pt(PPh
3
)
2
(C
7
H
10OBF
3
7
H
10OBF
3
2
-
t
bpy)(C ) (9), and Pt(Bu bpy)(C H10OBF
7
H10OBF
3
2 7 3
1
13
1
1
1
13
195
fully characterized by H, C, DEPT, H- H COSY, H- C COSY (HMQC), and
spectroscopy and elemental analysis. Three complexes (3, 6, 10) were characterized by single-crystal
Pt NMR
X-ray crystallography.
1
3–18
Introduction
-Metalla-2-oxacyclobutanes (metallaoxetanes) have been of
hydrogen peroxide,
by ketone addition to a carbene
1
9
11,12,20–22
complex, and by other less direct routes.
1
1
interest for a number of years as key species in alkene oxidation,
2–5
metal-mediated epoxide reactions, and other transformations.
Most recently, computational studies of the Wacker reaction
6
have implicated a protonated palladium metallaoxetane. Despite
this long-standing interest, relatively few metallaoxetanes have
been prepared and studied.
(
1)
The first metallaoxetanes are platinaoxetanes and are
produced by Pt(0) insertion into the C-O bond of the
activated epoxide tetracyanooxirane (2,2,3,3-tetracyanoox-
7
–9
In 2003, we reported the first isolation of a metalloxetane
acyclopropane) with PtL4 (L)AsPh3, PPh3). An analogous
2
3
from the reaction of an oxo complex (eq 1). This same oxo
complex oxidizes ethylene to acetaldehyde and propylene to
acetone presumably via analogous platinaoxetanes. More re-
cently, an auraoxetane has been obtained from the reaction of
reaction with isobutylene oxide is reported to also give a
1
0
platinaoxetane. Similarly, the Rh(I) complex Rh(PMe3)3Br
inserts into the C-O bond of isobutylene oxide to give a
1
1,12
rhodaoxetane.
Metallaoxetanes have also been obtained
2
4
a gold(III) oxo complex with norbornene.
from the reaction of alkene complexes with dioxygen or
(
13) Day, V. W.; Klemperer, W. G.; Lockledge, S. P.; Main, D. J. J. Am.
*
Corresponding author. E-mail: SharpP@missouri.edu.
Chem. Soc. 1990, 112, 2031–2033.
3
(
1) We limit this classification to complexes with sp C centers in the
(14) de Bruin, B.; Boerakker, M. J.; Donners, J. J. J. M.; Christiaans,
B. E. C.; Schlebos, P. P. J.; De Gelder, R.; Smits, J. M. M.; Spek, A. L.;
Gal, A. W. Angew. Chem., Int. Ed. Engl. 1997, 36, 2064–2067.
(15) Flood, T. C.; Iimura, M.; Perotti, J. M.; Rheingold, A. L.; Concolino,
T. E. Chem. Commun. 2000, 1681–1682.
metallaoxetane ring.
(
(
(
2) Jørgensen, K. A. Chem. ReV. 1989, 89, 431–458.
3) Jørgensen, K. A.; Schiøtt, B. Chem. ReV. 1990, 90, 1483–1506.
4) de Bruin, B.; Budzelaar, P. H. M.; Gal, A. W. Angew. Chem., Int.
Ed. 2004, 43, 4142.
(16) de Bruin, B.; Boerakker, M. J.; Verhagen, J. A. W.; de Gelder, R.;
Smits, J. M. M.; Gal, A. W. Chem.-Eur. J. 2000, 6, 298–312.
(17) de Bruin, B.; Brands, J. A.; Donners, J. J. J. M.; Donners, M. P. J.;
de Gelder, R.; Smits, J. M. M.; Gal, A. W.; Spek, A. L. Chem.-Eur. J.
1999, 5, 2921–2936.
(
(
5) Linic, S.; Barteau, M. A. J. Am. Chem. Soc. 2002, 124, 310–317.
6) Keith, J. A.; Nielsen, R. J.; Oxgaard, J.; Goddard, W. A. J. Am.
Chem. Soc. 2007, 129, 12342–12343.
7) Schlodder, R.; Ibers, J. A.; Lenarda, M.; Grazianilb, M. J. Am. Chem.
Soc. 1974, 96, 6893–6900.
8) Lenarda, M.; Pahor, N. B.; Calligaris, M.; Graziani, M.; Randaccio,
L. J. Chem. Soc., Dalton Trans. 1978, 279–282.
9) A recent example of an analogous reaction with an aziridine: Ney,
J. E.; Wolfe, J. P. J. Am. Chem. Soc. 2006, 128, 15415–15422.
10) Hase, T.; Miyashita, A.; Nohira, H. Chem. Lett. 1988, 219–222.
(
(18) de Bruin, B.; Verhagen, J. A. W.; Schouten, C. H. J.; Gal, A. W.;
Feichtinger, D.; Plattner, D. A. Chem.-Eur. J. 2001, 7, 416–422.
(19) Bazan, G. C.; Schrock, R. R.; O’Regan, M. B. Organometallics
1991, 10, 1062–1067.
(
(
(20) Klein, D., P.; Hayes, J. C.; Bergman, R. G. J. Am. Chem. Soc.
1988, 110, 3704–3707.
(
Attempts to duplicate this reaction in our laboratory have not been
successful. There is no reaction of isobutylene oxide with either the
originally reported Pt(PPh3)4 or Pt(PEt3)4. There is also no reaction between
(21) Hartwig, J. F.; Bergman, R. G.; Andersen, R. A. J. Am. Chem.
Soc. 1990, 112, 3234–3236.
(22) Hartwig, J. F.; Bergman, R. G.; Andersen, R. A. Organometallics
1991, 10, 3326–3344.
norbornene oxide and Pt(PPh3)4 or Pt(PEt3)4
11) Zlota, A. A.; Frolow, F.; Milstein, D. J. Am. Chem. Soc. 1990,
12, 6411–6413.
12) Calhorda, M. J.; Galvao, A. M.; Unaleroglu, C.; Zlota, A. A.;
Frolow, F.; Milstein, D. Organometallics 1993, 12, 3316–3325.
.
(
(23) Szuromi, E.; Shan, H.; Sharp, P. R. J. Am. Chem. Soc. 2003, 124,
10522–10523.
1
(
(24) Cinellu, M. A.; Minghetti, G.; Cocco, F.; Stoccoro, S.; Zucca, A.;
Manassero, M. Angew. Chem., Int. Ed. 2005, 44, 6892–6895.
1
0.1021/om7010479 CCC: $40.75  2008 American Chemical Society
Publication on Web 02/29/2008

A Family of Platinaoxetanes
Scheme 1
Organometallics, Vol. 27, No. 6, 2008 1235
spectra of 2 in CD2Cl2 and C6D6 display different patterns. The
NB fragment exhibits resonances for all 10 protons (one
overlapping with a COD peak) in C6D6. The most downfield
peak, a broad singlet at 6.62 ppm with Pt satellites (JPt-H ) 60
Hz), is assigned to the proton adjacent to the oxygen atom, H1
(
)
2
see Table 1). The most upfield singlet at 0.84 ppm with JPt-H
70 Hz is assigned to the Pt-bonded CH (H2). A singlet at
.06 ppm with weaker coupling to Pt (44 Hz) is assigned to
1
95
H3, the bridgehead hydrogen atom adjacent to the Pt-bonded
carbon atom. The COD olefinic protons trans to the carbon atom
appear at 5.26 ppm with no satellites. The COD olefinic protons
trans to the oxygen atom are found at 3.84 ppm with Pt satellites
(
1
JPt-H ) 59 Hz). The COD methylene protons are in the range
1
3
.89 to 1.33 ppm. C NMR spectra show 15 distinct carbon
25
Platinaoxetane 1 displays unusual reactivity, clearly indicat-
ing the need to further explore the chemistry of metallaoxetanes.
Although a number of oxo complexes have been prepared
previously in our group that could provide further examples of
metallaoxetanes, they are generally found to be unreactive with
13
195
resonances. A peak at 8.6 ppm shows a large C- Pt coupling
of 517 Hz and is assigned to a Pt-bonded norbornene carbon
atom, C2. C1, the oxygen-bonded norbornene carbon, is found
at 99.5 ppm with JPt-C ) 128 Hz.
26–39
Changing the NMR solvent to CD2Cl2 alters the appearance
of the H NMR spectrum of 2. Instead of a broad singlet, proton
alkenes.
Fortunately, expectedly facile displacement of 1,5-
1
COD by other ligands in 1 provides an excellent opportunity
to easily prepare a family of platinaoxetanes that are unavailable
by other means. In this paper we report new platinaoxetanes
both by simple COD displacement and by removal and
H1 appears as a doublet and is shifted upfield to 5.99 ppm with
JH-H ) 5 Hz and JPt-H ) 60 Hz. Other NB fragment protons
are similarly shifted upfield, but the olefinic protons trans to
the oxygen atom are shifted downfield to 4.19 ppm with
+
substitution of the Lewis acid fragment [(COD)Pt(Cl)] in 1.
1
95
1
13
somewhat stronger coupling to
Pt (75 Hz). The COD
The new complexes have been fully characterized by H, C,
1
1
1
13
195
methylene protons are shifted downfield to between 2.53 and
DEPT, H- H COSY, H- C COSY (HMQC), and
Pt
1
95
2
-
.05 ppm. The Pt NMR resonance for 2 is -2892 (C6D6) or
NMR spectroscopy and elemental analysis. Three have been
characterized by single-crystal X-ray crystallography.
2908 ppm (CD2Cl2).
Addition of BF3 · Et2O to an equimolar amount of 2, followed
by removal of the volatiles gives white platinaoxetane
COD)Pt(C7H10OBF3) (3) (Scheme 1). Complex 3 is also
obtained by reaction of BF3 · Et2O with 1, followed by removal
of [(COD)Pt(Cl)]2(BF4)2 (Scheme 1). Crystals of 3 are readily
obtained, and one was subjected to X-ray analysis, confirming
the formulation. A drawing of the solid-state structure of 3 is
given in Figure 1. Crystallographic data are summarized in Table
2. Selected bond distances and bond angles are given in Table
3. A discussion of the structure may be found below.
Results and Discussion
(
+
Removal and Substitution of [(COD)Pt(Cl)] in 1. Addition
of an equimolar amount of Et4NCl to a solution of 1 in CH2Cl2
1
95
gives a solution with a Pt NMR spectrum showing complete
loss of the peaks for 1 and two new peaks. One at -2908 ppm
is due to new neutral platinaoxetane (COD)Pt(C7H10O) (2), and
the other at -3338 ppm is due to (COD)PtCl2, indicating the
reaction stoichiometry shown in Scheme 1. The (COD)PtCl2 is
readily removed by precipitation with excess ether, leaving 2
in solution. Evaporation of the solvents gives white 2, which is
slightly soluble in hexane and soluble in ether, C6H6, and
CH2Cl2.
NMR spectra are similar to those for 2. Selected data are
1
given in Table 1. The H NMR spectrum of 3 in CD Cl shows
2
2
the COD olefinic protons trans to oxygen at 4.68 and 4.50 ppm
flanked with satellites (JPt-H ) 68 Hz). Although not equivalent,
the remaining COD olefinic protons are found as a single
multiplet peak at 5.79 ppm with satellites (JPt-H ) 38 Hz). The
H1 resonance is a doublet with satellites at 6.08 ppm with JH-H
) 5.7 Hz and JPt-H ) 33 Hz. The resonance of H2 is a doublet
of doublets at 1.41 ppm due to coupling to H1 and H3. The
two protons on C7 are found at 2.56 and 1.23 ppm. The other
protons of the NB fragment are indistinct because of overlap
with other peaks. In the spectrum in C6D6 all 10 NB fragment
protons are resolved. The H1 proton appears as a doublet shifted
downfield compared to CD2Cl2 to 6.42 ppm, but the H2 proton
is shifted upfield to 0.76 ppm. The two COD olefinic protons
trans to oxygen overlap and appear upfield from those in CD2Cl2
1
13
1
1
Complex 2 was characterized by H, C, DEPT, H- H
1
13
195
COSY, H- C COSY(HMQC), and Pt NMR spectroscopy
and elemental analysis. Crystals of 2 for X-ray analysis could
1
not be obtained. Table 1 gives selected NMR data. H NMR
(
25) Szuromi, E.; Wu, J.; Sharp, P. R. J. Am. Chem. Soc. 2006, 128,
1
2088–12089.
(
(
(
26) Singh, A.; Sharp, P. R. Dalton Trans. 2005, 2080–2081.
27) Anandhi, U.; Sharp, P. R. Inorg. Chem. 2004, 43, 6780–6785.
28) Anandhi, U.; Holbert, T.; Lueng, D.; Sharp, P. R. Inorg. Chem.
2
003, 42, 1282–1295.
(
(
(
29) Sharp, P. R. Dalton Trans. 2000, 2647–2657.
30) Sharp, P. R. Comments Inorg. Chem. 1999, 21, 85–114.
31) Li, J. J.; Li, W.; James, A. J.; Holbert, T.; Sharp, T. P.; Sharp,
1
95
P. R. Inorg. Chem. 1999, 38, 1563–1572.
at 3.63 ppm with satellites (JPt-H ) 80 Hz). The Pt NMR
resonance for 3 (-3103 ppm in C6D6, -3116 ppm in CD2Cl2)
is at a lower frequency than for 2 (-2891 ppm in C6D6).
(
(
(
(
32) Shan, H.; Sharp, P. R. Angew. Chem., Int. Ed. 1996, 35, 635–636.
33) Li, J. J.; Li, W.; Sharp, P. R. Inorg. Chem. 1996, 35, 604–613.
34) Li, J. J.; Sharp, P. R. Inorg. Chem. 1994, 33, 183–184.
35) Yang, Y.; Wu, Z.; Ramamoorthy, V.; Sharp, P. R. In The Chemistry
COD Ligand Substitution. PEt3 addition to 1 or 2 results
of the Copper and Zinc Triads; Welch, A. J., Chapman, S. K., Eds.; The
Royal Society of Chemistry: Cambridge, 1993.
in rapid substitution of the COD ligand with two PEt3 ligands
+
(
(
36) Yang, Y.; Sharp, P. R. Inorg. Chem. 1993, 32, 1946–1951.
and, in the case of 1, displacement of the [(COD)Pt(Cl)]
fragment as [Pt(PEt3)3(Cl)]+ (Scheme 2). The platinaoxetane
37) Li, W.; Barnes, C. L.; Sharp, P. R. J. Chem. Soc., Chem. Commun.
1
990, 1634–1636.
38) Ge, Y.-W.; Peng, F.; Sharp, P. R. J. Am. Chem. Soc. 1990, 112,
632–2640.
39) Sharp, P. R.; Flynn, J. R. Inorg. Chem. 1987, 26, 3231–3234.
product (PEt3)2Pt(OC7H10) (5) is readily isolated as a white solid
(
3
1
soluble in hydrocarbon solvents. The P NMR spectrum of 5
2
195
(
shows two doublets flanked by Pt satellites. The inequivalence

1
236 Organometallics, Vol. 27, No. 6, 2008
Wu and Sharp
a
Table 1. Selected NMR Data and Numbering Scheme
δ H1
δ H2
δ C1
δ C2
δ Pt
b,e
1
1
2
2
3
3
4
5
6
7
8
9
1
6.23 (JPt-H ) 32)
6.21 (JPt-H ) 34)
5.99 (JPtH ) 60)
6.62 (JPtH ) 60)
6.08 (JPtH ) 33)
6.42 (JPtH ) 33)
5.93
6.92 (JPtH ) 40)
6.65
5.97
6.16
1.36 (dd, JH-H ) 5.5, 2.2)
1.44 (d, JH-H ) 5.5, JPt-H ) 56)
0.69 (br s, JPtH ) 66)
110.3
107.7
98.7
99.5
101.2
19.9
16.6
8.8
8.6
18.6
-2965, -3099
b,e
d
d
1
-3054, -3110
b
- 2908
c
0.84 (br s, JPtH ) 70)
-2891
-3117
-3103
-3204
-3883
-4008
-4049
-4148
-4045
-4042
b
f
0.89 (m)
c
0.76 (dd, JH-H ) 5.7, 2.1)
1.36 (d, JH-H ) 5.4, JPtH ) 58)
0.77 (m, JPtH ) 40.5)
b,e
c
98.5
100.1
100.4
98.6
16.7
8.2
8.1
23.4
24.1
c
f
∼0.66
b
0.47 (d, JH-H ) 5.5)
0.77 (m)
b
100.9
b
5.92
5.92
1.66 (dd, JH-H ) 6, 2.5)
1.66 (dd, JH-H ) 5.5, 2)
b
0
102.0
3.8
a
b
c
d
e
f
Shifts in ppm, coupling constants in Hz. In CD2Cl2. In C6D6. In CD3NO2. From ref 23 and 25. Overlapping with another peak.
Table 3. Selected Distances (Å) and Angles (deg) for 3, 6, and 10
3
6
10
Pt1-O1
2.038(3)
2.052(5)
1.466(6)
1.551(7)
1.484(7)
2.126(5)
2.126(5)
2.321(5)
2.301(5)
2.1459(18)
2.071(3)
1.471(3)
1.540(4)
1.486(4)
2.055(3)
2.023(4)
1.467(5)
1.525(6)
1.484(6)
Pt1-C1
O1-C2
C1-C2
O1-B1
Pt1-C8
Pt1-C9
Pt1-C12
Pt1-C13
Pt1-P1
2.2027(7)
2.3532(8)
Pt1-P2
Pt1-N1
2.117(3)
1.973(3)
69.20(14)
94.9(2)
127.5(3)
117.9(3)
94.4(3)
Pt1-N2
Figure 1. Drawing of the solid-state structure of 3 (50% probability
ellipsoids, hydrogen atoms omitted for clarity).
O1-Pt1-C1
C2-O1-Pt1
B1-O1-Pt1
C2-O1-B1
C2-C1-Pt1
C1-C2-O1
68.93(16)
97.1(3)
136.0(3)
126.4(4)
93.8(3)
68.31(9)
93.37(13)
127.92(18)
116.0(2)
94.31(16)
103.7(2)
Table 2. Crystal Data and Structure Refinement Details for 3, 6,
a
and 10
100.2(4)
101.4(3)
3
6
10
formula
fw
C15H22BF3OPt
C19H40BF3OP2Pt ·
C6H6
687.46
P21/n
C25H34BF3N2OPt ·
1.125(C7H8)
745.09
Scheme 2
481.23
space group Pbca
C2/c
a, Å
b, Å
c, Å
R, deg
13.6535(6)
9.8764(11)
21.340(2)
13.5382(14)
90
93.188(2)
90
2849.0(5)
4
1.603
30.3734(12)
10.4959(4)
23.0024(9)
90
97.1150(10)
90
7276.6(5)
8
1.360
11.6850(5)
18.6671(8)
90
90
90
2978.2(2)
8
2.147
9.450
0.0287, 0.0614 0.0219, 0.0436
1.038 1.017
ꢀ
, deg
γ, deg
3
V, Å
Z
3
dcalc, g/cm
-
1
µ, mm
5.073
3.896
0.0350, 0.0823
0.996
b
c
R1 , wR2
Gof
(JP-Pt ) 3485 Hz) than the downfield doublet at 14.42 ppm
(JP-Pt ) 1566 Hz) and is assigned to the P atom trans to the
a
b
λ ) 0.71070 Å (Mo), T ) -100 °C. R1 ) (∑||Fo| - |Fc||)/∑|Fo|.
40,41
c
2
2 1/2
2
2 2
more weakly donating oxygen atom.
The downfield doublet
wR2 ) [(∑w(||Fo| - |Fc||) )/∑wFo ] ; w ) 4Fo /(∑Fo ) .
is then assigned to the P atom trans to the more strongly
donating carbon atom of the platinaoxetane ring. In CD2Cl2 the
shifts and coupling constants are similar to those in C6D6 except
for the Pt-P coupling trans to the oxygen atom. This increases
of the phosphine ligands and the small P-P coupling of 5 Hz
indicate a cis-phosphine geometry at the Pt center. In C6D6 the
upfield doublet at -0.04 ppm shows much larger Pt-P coupling

A Family of Platinaoxetanes
Scheme 3
Organometallics, Vol. 27, No. 6, 2008 1237
from 3485 to 3600 Hz, suggesting some alteration in the Pt-O
bonding as the solvent polarity increases. This effect is also
observed for the other phosphine complexes discussed below.
Figure 2. Drawing of the solid-state structure of 6 (50% probability
ellipsoids, hydrogen atoms omitted for clarity).
195
A comparison of the Pt coupling constants of 5 with known
given in Table 3. Details of the structure are discussed below.
42
3
1
Pt(PEt3)2(OMe)(Me) would be useful for evaluating the donor
P NMR spectra in C6D6 show two doublets at 20.62 and 0.56
1
95
properties of the oxetane ring. Unfortunately, Pt(PEt3)2-
ppm flanked by
Pt satellites, which are shifted downfield
1
95
(
OMe)(Me) has a trans geometry. Platinacyclobutane complex
compared to those of 5. The largest Pt coupling constant for
the P atom trans to the oxygen atom is 4570 Hz in C6D6 but
increases to 4730 Hz in CD2Cl2. The effect on the coupling
constant for the P atom trans to the carbon atom is much smaller,
where the constant changes only slightly from 1644 Hz in C6D6
to 1659 Hz in CD2Cl2. In comparison to 5 in C6D6, the coupling
constant for the P atom trans to the oxygen atom has increased
by almost 1100 Hz. This is attributed to the coordination of the
Lewis acid BF3 to the oxygen atom, strongly reducing its
4
3
Pt(Et3P)2(CH2)4 has a coupling constant (1782 Hz) that is ca.
00 Hz greater than the smallest for 5, suggesting that the carbon
atom of 5 is a better donor. The Pt-P coupling trans to the O
44,45
1
2
+
atom is similar to that of [(Et3P)2Pt(µ-OH)]2 (3475 Hz),
suggesting that the O atom of 5 is a weaker donor than might
195
be expected for an alkoxo-type ligand. The Pt NMR spectrum
of 5 in C6D6 shows a doublet of doublets at -3883 ppm, further
confirming coupling between the Pt center and two different
phosphine ligands.
4
0,41
donating ability.
The coupling constant (1644 Hz) for the
1
H NMR spectra of 5 show all 10 proton peaks for the
P atom trans to the C atom is slightly greater than that (1566
Hz) of precursor 5. The P-Pt coupling constants for 6 can be
compared to the protonated methoxo complex cis-[Pt-
norbornene fragment in addition to resonances for the phosphine
ligands. None of the norbornene peaks display coupling to the
3
1
+
46
P nuclei of the phosphine ligands. The most downfield signal
at 6.92 ppm is assigned to H1 and the most upfield signal at
.77 ppm is assigned to H2 (Table 1). Both display similar
(
PEt3)2(HOMe)(Me)] . Although unstable with respect to the
trans isomer, this complex has been generated and characterized
195
0
in solution and displays Pt coupling constants of 4344 (trans
to O) and 1829 (trans to C) Hz, again suggesting a relatively
weak O atom donor and a relatively strong C atom donor for
1
95
coupling to Pt (∼40 Hz), which is ∼20 Hz (H1) or ∼30 Hz
H2) less than that of 2. H3 show similar coupling to that of 2.
Signals for the seven different carbons atoms of the norbornene
(
the platinaoxetane. The six-membered ring complex [Pt-
13
+
fragment are observed in the C NMR spectrum with the signal
(
PEt3)2(CHCF3CCF3dCMeOMe)] , where the ether group
1
for the Pt-bonded carbon atom at 8.2 ppm. As in the H NMR,
coordinates to the Pt center, also shows similar coupling for
4
7
195
the norbornene fragment peaks do not show coupling to the
the P atom trans to the oxygen atom (4530 Hz). The Pt
NMR resonance of 6 in C6D6 is found as a doublet of doublets
at -4008 ppm, shifted upfield by about 120 ppm from that of
3
1
P nuclei.
Addition of an equimolar amount of BF3 · Et2O to 5 im-
mediately affords the white BF3 adduct (Et3P)2Pt(C7H10OBF3)
1
13
5
5
. H and C NMR spectra show similar patterns to those of
1
95
(
6) in high yield (Scheme 3). Complex 6 is also available by
, but Pt coupling with H1 and H2 is not observed.
COD ligand displacement via addition of 2 molar equiv of PEt3
Treatment of 3 with PPh3 affords the PPh3 analogue of 6,
1
13
31
to 3 (Scheme 3). Complex 6 has been characterized by H, C,
Pt(Ph3P)2(C7H10OBF3) (7) (Scheme 3). The P NMR spectrum
of 7 shows the expected pair of doublets with satellites. As
1
1
1
13
195
DEPT, H- H COSY, H- C COSY (HMQC), and
Pt
3
1
195
NMR spectroscopy, elemental analysis, and X-ray crystal-
lography. A drawing of the solid-state structure of 6 is shown
in Figure 2. Crystallographic data and data collection parameters
are summarized in Table 2. Selected distances and angles are
observed for 6, the P- Pt coupling constants are solvent
dependent. In CD2Cl2, a large value of 5122 Hz is observed for
the P atom trans to the O atom, while in C6D6 the observed
1
95
value is 4980 Hz. As observed for 6, the Pt spectrum of 7
exhibits a doublet of doublets at -4049 ppm.
(
40) Pidcock, A.; Richards, R. E.; Venanzi, L. M. J. Chem. Soc. A 1966,
707–1710.
41) Appleton, T. G.; Clark, H. C.; Manzer, L. E. Coord. Chem. ReV.
973, 10, 335–422.
42) Arnold, D. P.; Bennett, M. A. J. Organomet. Chem. 1980, 199,
Addition of 1 equiv of dppe to a solution of 3 results in rapid
formation of Pt(dppe)(C7H10OBF3) (8) as a white precipitate
1
(
3
1
(
Scheme 3). The P NMR spectrum in CD2Cl2 shows two
1
1
95
195
(
singlets with
Pt satellites. The large difference in
Pt
C17–C20.
coupling constants (3030 Hz) of the two P atoms is similar to
(
43) Young, G. B.; Whitesides, G. M. J. Am. Chem. Soc. 1978, 100,
5
808–5815.
(
44) Mintcheva, N.; Nishihara, Y.; Tanabe, M.; Hirabayashi, K.; Mori,
(46) Alibrandi, G.; Minniti, D.; Monsu Scolaro, L.; Romeo, R. Inorg.
Chem. 1988, 27, 318–324.
A.; Osakada, K. Organometallics 2001, 20, 1243–1246.
45) Bushnell, G. W.; Dixon, K. R.; Hunter, R. G.; McFarland, J. J.
Can. J. Chem. 1972, 50, 3694.
(
(47) Clark, H. C.; McBride, S. S.; Payne, N. C.; Wong, C. S. J.
Organomet. Chem. 1979, 178, 393–408.

1
238 Organometallics, Vol. 27, No. 6, 2008
Wu and Sharp
that in 6 (3070 Hz) and 7 (3054 Hz) and consistent with the
formation of a five-membered chelate ring with one P atom trans
to the carbon atom and one trans to the O atom of the
platinaoxetane ring. The chemical shifts of 48.4 and 30.7 ppm
48
are also consistent with dppe chelation. The coupling constant
4730 Hz) of the P atom trans to the weakly donating oxygen
(
atom in CD2Cl2 is identical to that of 6 (4730 Hz) and is
comparable to that of the P atom trans to the triflate oxygen
4
9
atom of Pt(dppe)(R)OTf (R ) n-C3F7, 4651 Hz; R ) Me,
5
0
4
646 Hz ), indicating that the O atom of 8 is a comparable
donor to the triflate anion. As observed for the other phosphine
complexes (see above), the P-Pt coupling decreases in C6D6,
1
95
in this case by 146 to 4584 Hz. The
Pt resonance of 8 is
found as a doublet of doublets at -4148 ppm. The poor
solubility of 8 in common organic solvent precluded recording
13
a strong C NMR spectrum, but inequivalence of the two dppe
methylene carbons is observed (29.5 and 25.1 ppm). Both
display a doublet of doublets pattern due to coupling to the two
inequivalent P atoms.
Figure 3. Drawing of the solid-state structure of 10 (50% probability
ellipsoids, hydrogen atoms omitted for clarity).
COD substitution by diimines is much slower than COD
substitution by phosphines and reveals reaction rate differences
between platinaoxetane 2 and 3. Addition of 4,4′-di-tert-buty-
195
because of its poor solubility in common organic solvents. Pt
resonances are found at -4045 ppm (9) and -4042 ppm (10).
Complex 10 has been characterized by X-ray crystallography.
A drawing of the structure is shown in Figure 3. Crystallographic
data and data collection parameters are summarized in Table
t
l-2,2′-bipyridine (Bu 2bpy) to (COD)Pt(C7H10O) (2) in C6D6
shows no observable change after 1 day at room temperature.
Heating the mixture at 54 °C for 5 days and then 75 °C for 2
days still shows mostly 2. Complex 2 is mostly consumed after
the mixture is heated at 110 °C for another day, resulting in a
2
. Selected distances and angles are given in Table 3.
Structures. We will begin this section by comparing the
1
structures of 3, 6, and 10. These complexes differ only by the
identity of the ancillary ligand set trans to the platinaoxetane
ring, and the overall structures are correspondingly very similar.
In keeping with the trans influence trend N-donor < alkene <
brown precipitate and a dark red solution. The H NMR
spectrum of the precipitate in CD2Cl2 suggests the presence of
two complexes. Attempts to purify the material were unsuccessful.
t
In contrast to 2, addition of Bu 2bpy to (COD)Pt(C7H10OBF3)
51
phosphine, the Pt-C distances increase in the order 10 < 3
(
3) in C6D6 results in the formation of a bright yellow solution
<
6. The Pt-O distance in 6 is also the longest, but the order
after 2 days at room temperature (Scheme 3). Once free COD
is removed from the mixture, pure 10 is readily obtained as a
yellow solid, slightly soluble in toluene and benzene and soluble
in methylene chloride. The much less soluble 4,4′-di-tert-buty-
l-2,2′-bipyridine (Me2bpy) analogue of 10, (Me2bpy)Pt-
of 10 and 3 is inverted such that the Pt-O distance of 3 is the
shortest. While the difference between the two values is small
and may not be significant, other factors indicate an anomaly
in 3. The B-O-Pt angles for 10 and 6 are nearly identical at
1
28°, while that for 3 is nearly 10° larger at 136°. The other
(
C7H10OBF3) (9), is similarly prepared by addition of Me2bpy
angles around the O atoms are also larger for 3 but nearly
identical for 6 and 10, indicating a more planar O atom for 3.
The planarity of the O atom is evident from the deviation of
the boron atom, B1, from the essentially planar platinaoxetane
ring. The boron atom of 3 is only 0.13 Å out of the Pt1, O1,
C1, and C2 least-squares plane (largest deviation 0.008 Å). In
contrast, B1 of 6 and 10 are 0.85 and 0.83 Å, respectively, out
of their least-squares planes (largest deviation 0.039 Å (6) and
to 3 in CH2Cl2 (Scheme 3). Precipitation of white 9 is complete
after ca. 24 h. Complex 9 is sparsely soluble in common organic
solvents including DMSO. The difference in COD substitution
rates for 2 and 3 may be attributed to the lower electron density
on the Pt center in 3 as a result of BF3 bonding to the O atom
of 3. The Pt center is more electrophilic for the incoming
diimine, and there is reduced back-bonding to the COD ligand,
allowing more facile COD substitution.
0
.028 Å (10)). Electronic factors in this difference can be
1
H NMR spectra for diimine complexes 9 and 10 are very
eliminated by the fact that the closely related platinaoxetane 4
(see Table 1), previously reported by our group, more closely
matches the structures of 6 and 10 with the boron atom 0.93 Å
out of the platinaoxetane ring plane (largest deviation 0.007 Å).
Thus, it seems likely that the deviation of 3 is due to crystal-
packing forces.
Other features in the platinaoxetane rings of 3, 6, and 10 are
essentially identical. The C2-O1 bond distances are equal at
.47 Å, as are the B1-O1 distances at 1.48 Å. There is some
variation in the C1-C2 distances but within the experimental
error. Similarly, there is little variation in the angles within the
ring other than those around O1, as already discussed.
In comparing the structures of 3, 6, and 10 to other
metallaoxetanes, a noticeable feature is that 3, 6, and 10 (and
similar. Both exhibit, in addition to the methyl protons, six
distinct peaks in the aromatic region for the bipyridine ring
protons and 10 peaks for the NB fragment’s protons, consistent
with the absence of symmetry in the complexes. Chemical shifts
for H1 (in CD2Cl2) are found at 5.92 ppm in both complexes
25
1
95
with no
Pt satellites and are comparable to those of the
phosphine and COD platinaoxetanes (Table 1). The Pt-CH (H2)
resonances are found as doublets of doublets at 1.68 ppm (for
1
1
0) and 1.66 ppm (for 9) with JPt-H ≈ 54 Hz. The most upfield
13
signals (3.8 ppm) in the C spectra of 10 is assigned to the Pt
σ-bonded carbon. C NMR spectra of 9 are not available
1
3
(
(
48) Garrou, P. E. Chem. ReV. 1981, 81, 229–266.
25
49) Hughes, R. P.; Sweetser, J. T.; Tawa, M. D.; Williamson, A.;
the other members of this class, 1 and 4) contain planar rings,
Incarvito, C. D.; Rhatigan, B.; Rheingold, A. L.; Rossi, G. Organometallics
2
001, 20, 3800–3810.
50) Hill, G. S.; Yap, G. P. A.; Puddephatt, R. J. Organometallics 1999,
8, 1408–1418.
(
(51) Huheey, J. Inorganic Chemistry: Principles of Structure and
ReactiVity; Harper & Row: Philidelphia, 1983.
1

A Family of Platinaoxetanes
Organometallics, Vol. 27, No. 6, 2008 1239
whereas most other metallaoxetanes contain “puckered” rings,
including the closely related Pt(II) complexes Pt(AsPh3)2-
larger ring complexes. The effect of the ligands and BF3 and
other Lewis acids on the reactivity and stability of the plati-
naoxetanes is now under study in our laboratories and will be
reported shortly.
7
8
(
C2(CN)4O) and Pt(PPh3)2(C(CN)2CH(CN)O). Only three
8
other metallaoxetanes are planar. One of these is the Au(III) d
+
24
complex [Au(6-Me-bpy)(C7H10O)] , a close relative of 10 but
without a BF3 bonded to the ring O atom. The other two are
Experimental Section
6
the Rh(III) d octahedral complexes Rh(PMe3)3(Br)(CH2-
1
1,12
+
General Procedures. Experiments were performed under a
dinitrogen atmosphere in a Vacuum Atmosphere Corporation
drybox. Solvents were dried by standard techniques and stored under
dinitrogen over 4 Å molecular sieves or sodium metal. Alkenes
CMe2O)
and [Rh(MeTPA)(CH2CMe2O)] (MeTPA ) N-[(6-
16
methyl-2-pyridyl)methyl]-N,N-di(2-pyridylmethyl)amine). No
trend is evident in this set, suggesting that planar versus
puckered rings is a subtle feature of metallaoxetanes.
were purchased from Acros or Aldrich. PEt
was obtained from Strem. BF · Et O, PPh , and bis(diphenylphos-
phino)ethane (dppe) were obtained from Acros, and 4,4′-dimethyl-
,2′-bipyridine (Me bpy) and 4,4′-di-tert-buty-l-2,2′-bipyridine (Bu
bpy) were purchased from Aldrich. All commercial chemicals were
used as received except where noted. Complex 1 was synthesized
3
(10 wt % in hexane)
The Pt-C and Pt-O distances of 6 are best compared with
3
2
3
7,8
Pt(AsPh3)2(C2(CN)4O) and Pt(PPh3)2(C(CN)2CH(CN)O). The
Pt-C distances of 2.103(7) and 2.13(2) Å appear marginally
longer than those in 6 probably as a result of the CN substituents.
The Pt-O distances of 2.050(5) and 2.06(2) Å are substantially
shorter than that of 6 (2.1459(18) Å). This may be attributed to
the BF3 coordination to the O atom, which should lengthen the
2
2
2
t
2
3
by literature procedures. NMR spectra were recorded on Bruker
AMX-250, -300, or -500 spectrometers at ambient probe temper-
atures. Data are given in ppm relative to solvent signals referenced
3
1
195
Pt-O bond in 6, as suggested by the large P- Pt coupling
constant for the P atoms trans to the ring O atom (see above).
In fact, this is the longest observed M-O distance in any
1
13
to TMS for H and C spectra or relative to external standards for
1
95
31
Pt (K
2
PtCl
4
/D
3
2
O at -1624 ppm), P (85% H
3 4
PO at 0.0 ppm),
1
9
reported metallaoxetane but is comparable to the ether complex
and F (CFCl
at 0.0 ppm). Atom numbering for the peak
+
assignments is given in Table 1 and below. Desert Analytics, Inc.
performed the elemental analyses (inert atmosphere).
[
Pt(PEt3)2(CHCF3CCF3dCMeOMe)] , where the Pt-O dis-
31
195
tance is 2.144(9) Å and the trans to O atom P- Pt coupling
47
(COD)Pt(OC H ) (2). A solution of Et NCl (39 mg, 0.238
7
10
4
constant is similar to that of 6 (see above). Similarly, the Pt-O
mmol) in 1 mL of CH
2
Cl
2
was added dropwise to an agitated
bond distance of the tethered ether complex [Pt(Ph2-
PCH2CH2OMe)2Cl]+ is 2.192(7) Å.52
solution of platinaoxetane 1 (200 mg, 0.238 mmol) in 2 mL of
CH Cl . After 20 min, ether was added dropwise until precipitate
formation ceased. The (COD)PtCl precipitate was removed by
filtration, and the filtrate was evaporated to dryness in vacuo. The
Cl and excess ether
2
2
M-atom distances in 10 are comparable to those in [Au(6-
+
2
Me-bpy)(C7H10O)] with recognition of the difference in metal
2
4
ionic radii. The Au-C and Au-N distances of [Au(6-Me-
bpy)(C7H10O)]+ are larger than the corresponding ones for 10
by 0.032, 0.068, and 0.051 Å, consistent with the larger ionic
radius of Au(III). (A difference of 0.08 Å is found in a listing
of ionic radii.) In contrast, the Au-O distance is smaller by
residue was redissolved in ∼0.5 mL of CH
2
2
was added. The resulting small amount of precipitate was removed
by filtration. Evaporation of the filtrate gave white product 2, which
was dried in vacuo. Yield: 74.6 mg, 76%. Anal. Calcd (found) for
1
C
15
H
22OPt · 0.25CH
2 2
Cl : C, 42.16 (42.45); H, 5.07 (5.22). H NMR
0
.088 Å, suggesting that there is an elongation of the Pt-O
(
500 MHz, CD Cl
2
2
): 5.99 (d with satellites, JH-H ) 5 Hz, JPt-H
)
bond of 0.12 Å (0.088 + 0.032) to 0.16 Å (0.088 + 0.068)
upon coordination of the BF3 group. This puts the expected
Pt-O bond distance of the BF3-free complex 5 at 1.99 to 2.02
Å, a Pt-O distance in the range observed for Pt(dppe)(OMe)2
6
0 Hz, 1H, H1), 5.55 (br s with satellites, JPt-H ≈ 70 Hz, 1H, COD
CH), ∼5.28 (m, overlapping with solvent residue peak, 1H, COD
CH), 2.41 (overlapping with COD CH , 1H, H4), 2.39 (br, s, 1H,
2
H6), 2.06 (s, 1H, H3), 2.35 (overlapping with H4) and 2.06 (m’s,
5
3
(
2.041(7), 2.037(7) Å) and Pt(dppe)(OMe)Me (1.99(1) Å).
As noted above, the C-O distances in 3, 6, and 10 are all
similar at 1.47 Å. This lies at the upper end of the range of
.36 to 1.45 Å for all but one of the reported metallaoxetanes.
8H, COD CH
2
), 1.45 (m, 1H, H5), 1.35 (m, 1H, H7), 1.01 (d, JH-H
) 9 Hz, 1H, H4′), 0.90 (br m, 1H, H7′), 0.79 (m, 1H, H5′), 0.69
1
(
br s with satellites, JPt-H ) 66 Hz, 1H, H2). H NMR (500 MHz,
): 6.62 (m with satellites, JPt-H ) 60 Hz, 1H, H1), 5.26 (m,
6 6
C D
1
2
-
2H, COD CH), 3.84 (m with satellites, JPt-H ≈ 59 Hz, 2H, COD
The one exception is [Ir(P3O9)(C8H12O)] , which has a C-O
distance of 1.858 Å. Such an exceptionally long distance must
be considered with caution. The C-C ring distances of 3, 6,
and 10 vary somewhat more but fall within the range (1.43-1.58
Å) of the other metallaoxetanes.
CH), 2.81(s, br, 1H, H4), 2.39 (s, br, 1H, H6), 2.06 (s with satellites,
J
Pt-H ) 43.5 Hz, 1H, H3), 1.89, 1.74, 1.66, 1.56 and 1.33 (m’s,
8
H total, COD CH
2 2
), 1.57 (s, 1H overlapping with COD CH at
1
(
J
(
.56, H7), 1.47 (m, 1H, H5), 1.20 (d, JH-H ) 9 Hz, 1H, H4′), 1.05
br m, 1H, H7′), 0.97 (br m, 1H, H5′), 0.84 (br s with satellites,
1
3
1
6 6
Pt-H ) 70 Hz, 1H, H2). C{ H} NMR (75 MHz, C D ): 111.4
COD CH), 111.3 (COD CH), 99.5 (JPt-C ) 128.3, C1), 73.2 (JPt-C
182.6, COD CH), 72.9 (JPt-C ) 197.0 (COD CH), 43.8 (C6),
40.3 (C3), 36.7 (C4), 32.2 (C7), 31.8 (COD CH ), 31.5 (COD CH ),
Conclusions
)
In conclusion, the platinaoxetane ring of 1 survives displace-
2
2
ment and substitution with BF3 of the oxygen-coordinated
27.5 (COD CH
2
), 27.2 (COD CH
C2). Pt NMR (64 MHz, C ): -2891.
(COD)Pt(C ) (3). From 2. BF
mmol) was added to an agitated solution of platinaoxetane 2 (9.0
mg, 0.022 mmol) in 1 mL of CH Cl . The solvent was evaporated
2
), 23.3 (C5), 8.6 (JPt-C ) 517.6,
+
195
[Pt(COD)Cl] fragment and substitution of the COD ligand with
6 6
D
phosphines and bipyridine ligands, giving access to a family of
platinaoxetanes. Spectroscopic and structural parameters of the
complexes are consistent with the expected trans influence of
the ligands and with the BF3 bonding to the platinaoxetane ring
7
H
10OBF
3
3
2
· Et O (2.6 µL, 0.022
2
2
to give pure product 3. Yield: 10.2 mg, 95%.
From 1. This procedure is similar to that reported previously
3
1
oxygen atom. P NMR data suggest that the O atom of the
platinaoxetane is a weaker donor than comparable acyclic or
but with an improved workup giving higher yields. BF
µL, 0.14 mmol) was added to an agitated solution of platinaoxetane
(118 mg, 0.14 mmol) in 2 mL of CH Cl . After 4 min the resulting
3
2
· Et O (18
1
2
2
(
52) Anderson, G. K.; Corey, E. R.; Kumar, R. Inorg. Chem. 1987, 26,
7–100.
53) Bryndza, H. E.; Calabrese, J. C.; Marsi, M.; Roe, D. C.; Tam, W.;
Bercaw, J. E. J. Am. Chem. Soc. 1986, 108, 4805–4813.
precipitate was removed by filtration. Excess ether was added to
the filtrate, and the resulting small amount of precipitate was
removed. The clear solution was evaporated to dryness and
9
(

1
240 Organometallics, Vol. 27, No. 6, 2008
Wu and Sharp
redissolved in minimum CH Cl . Excess hexane was added, and
2
2
(m, 1H, H7′), 1.20 (m, 6H, PCH
2
Me), 0.98 (m, 1H, H4′), 0.96 (br
the mixture was kept at -30 °C for 1 day. The resulting white
precipitate was collected, washed with cold hexane, and dried in
vacuo. Colorless single crystals for the X-ray analysis were grown
m, 1H, H5′), 0.88 (m, 9H, -CH ), 0.70 (m, 9H, -CH ), ∼0.66
3
3
(overlapping with -CH peak at 0.88, H2).
3
13
1
C{ H} NMR (126 MHz, CD
2
Cl
2
): 100.5 (C1), 44.1 (C6), 42.4
from CH
2
Cl
3
2
/hexane. Yield: 52 mg, 78%. Anal. Calcd (found) for
Pt: C, 37.43 (36.86); H, 4.58 (4.43). NMR data in
1
(
C3), 36.1 (C7), 32.4 (C4), 22.7 (C5), 17.4 (dd,
J
P-C ) 40.3 Hz,
Me),
), 8.31 (C2). C{ H} NMR (126
): 100.4 (C1), 44.4 (C6), 42.5 (C3), 36.1 (C7), 32.6
C
15
H22OBF
3
JP-C ) 3.8 Hz, PCH
2
Me), 15.4 (d, JP-C ) 27.7 Hz, PCH
2
2
5 1
CD
2
Cl
2
have been previously reported.
H NMR (300 MHz,
13
1
8
.59 (PCH CH ), 8.57 (PCH CH
MHz, C
C4), 22.8 (C5), 16.5 (dd,
PCH
PCH
2
3
2 3
6 6
C D ): 6.42 (d with satellites, JH-H ) 5.7 Hz, JPt-H ) 33 Hz, 1H,
H1), 5.78 (m, 1H, COD CH), 5.78 (m, 1H, COD CH), 3.63 (m
6
D
6
1
3
(
JP-C ) 40.3 Hz,
J
P-C ) 7.5 Hz,
P-C ) 5.0 Hz,
with satellites, JPt-H ≈ 80 Hz, 2H, COD CH), 2.85 (br s, 1H, H4),
1
3
2
Me) and 14.9 (dd,
Me), 8.2 (PCH CH
): 20.6 (d with satellites, JPt-P )1644 Hz, JP-P
JP-C ) 17.6 Hz,
J
2
1
1
.43 (d, JH-H ) 9.9 Hz, 1H, H6), 1.61 (s, 1H, H3), 1.48, 1.27,
3
1
2
2
3
), 8.1 (PCH CH
2
3
), 8.1 (C2). P NMR
.19, 1.09, and 0.86 (m’s, 8H total, COD CH
.22 (m, 1H, H5), 1.07 (d, JH-H ) 2.1 Hz, 1H, H4), 0.76 (dd, JH2-H1
5.7 Hz, JH2-H3 ) 2.1 Hz, 1H, H2), 0.68 (d, JH-H ) 2.1 Hz, 1H,
2
), 1.35 (s, 1H, H7),
(
9
101 MHz, C
6
D
6
)
3
1
.7), 0.6 (br s with satellites, JPt-P ) 4570). P NMR (101 MHz,
) 1659 Hz, J ) 9.8 Hz),
)
195
CD Cl ): 20.8 (d with satellites, J
H7), 0.65 (d, JH-H ) 2.1 Hz, 1H, H5). Pt NMR (C
6 6
D , 64 MHz):
2
2
Pt-P
P-P
1
95
1
.6 (br s with satellites, JPt-P ) 4730 Hz).
or CD Cl ): -4008 (dd, JPt-P1 ) 1690 Hz, JPt-P2 ) 4807
Hz). F NMR (235 MHz, C
MHz, CD Cl ): -149.2 (m).
(PPh Pt(C ) (7). A solution of PPh
mmol) in 0.3 mL of C was added to an agitated solution of 3
(4.0 mg, 0.0083 mmol) in 0.2 mL of C . After 1 h, the mixture
Pt NMR (64 MHz,
–
3103 (s).
PEt Pt(OC
0% solution, 0.026 mmol) was added dropwise to an agitated
. After 5
C
6
D
6
2
2
(
3
)
2
7 3
H10) (5). From 2. PEt in hexane (45 µL of a
1
9
19
6
6
D ): -148.6 (br s). F NMR (235
1
solution of 2 (5.4 mg, 0.013 mmol) in 0.5 mL of C
6
D
6
2
2
min, the volatiles were removed in vacuo. The resulting oily residue
was redissolved in toluene, and the mixture was evaporated to
dryness and left in vacuo for 2 h. This procedure was repeated for
3
)
2
7
H10OBF
3
3
(4.3 mg, 0.017
6
D
6
6
D
6
two or three times until residual COD and PEt
and a solid residue was obtained. The residue was washed with
3
were eliminated
was evaporated to dryness and the residue was dissolved in
minimum CH Cl . Excess hexane was added to precipitate white
2
2
hexane and dried in vacuo to give white solid 5. Yield: 6.8 mg,
solid 7. The solution was carefully decanted off the product, which
was washed with hexane and dried in vacuo. Yield: 6.6 mg, 88%.
9
8%.
From 1. PEt
was added to a solution of 1 (8.0 mg, 0.0095 mmol) in 0.4 mL of
CH Cl . After 10 min, excess hexane was added and a white
precipitate of [(PEt Pt(Cl)]BF formed. The clear solution was
decanted off the precipitate and evaporated in vacuo to give white
solid 5. Yield: 4.2 mg, 81%. Anal. Calcd (found) for C19 Pt:
): 6.92
m with satellites, JPt-H ) 40 Hz, 1H, H1), 3.24 (d, JH-H ) 5.1
Hz, 1H, H7), 2.65 (br s, 1H, H6), 2.54 (s, JPt-H ) 39 Hz, 1H, H3),
.01 (m, 1H, H4), 1.71 (m, 1H, H5), 1.59 (m, 6H, PCH Me), 1.51
d, JH-H ) 8 Hz, 1H, H4′), 1.48 (t, JH-H ) 9.6 Hz, 6H, PCH Me),
.44 (br m, 1H, H7′), 1.30 (br m, 1H, H5′), 1.08 (m, 9H, CH ),
.00 (m, 9H, C H ), 0.77 (m with satellites, JPt-H ) 40.5 Hz, 1H,
): 100.1 (C1), 46.0 (C6), 41.6
in hexane (82 µL of a 10% solution, 0.047 mmol)
Anal. Calcd (found) for C44
H
43OBF
3
P
2
Pt · 0.5CH
(56.00); H, 4.71 (5.30). H NMR (500 MHz, CD
2
Cl
Cl
2
: C, 55.92
): 7.56 (m,
3
1
2
2
6H, Ph), 7.30 (m, 18H, Ph), 7.15 (m, 6H, Ph), 5.97 (br s, 1H, H1),
2.77 (d, JH-H ) 9.5 Hz, 1H, H7), 2.39 (br s, 1H, H6), 1.65 (br s,
1H, H3), 1.26 (s, 1H, H5), 1.16 (d, JH-H ) 7.5 Hz 1H, H7′), 0.87
2
2
3
)
3
4
H
40OP
2
(m, 1H, H4), 0.69 (br m, 1H, H5′), 0.47 (d, J
H-H
) 5.5 Hz, 1H,
1
13
1
C, 42.14 (41.78); H, 7.38 (6.93). H NMR (500 MHz, C
(
6
D
6
H2), 0.21 (t, JH-H ) 9.9 Hz, 1H, H4′). C{ H} NMR (75.5 MHz,
CD Cl ): 133.71 (d, JP-C ) 11.3 Hz), 133.11 (d, JP-C ) 10.6 Hz),
29.97 (s), 128.87 (s), 127.15 (d, JP-C ) 11.3 Hz), 126.71 (d, JP-C
9.8 Hz), 98.6 (s, C1), 42.8 (C6), 39.8 (C3), 34.7 (C7), 30.1 (C4),
2
2
1
2
(
1
1
2
)
31
2
2
3.4 (C2), 21.0 (C5). P NMR (101 MHz, CD
2 2
Cl ): 27.66 (d with
3
satellites, JPt-P ) 1671 Hz, JP-P ) 8.9 Hz), 11.49 (br s with
31
3
satellites, JPt-P ) 5122 Hz). P NMR (101 MHz, C
6 6
D ): 27.77 (d
1
3
1
6 6
H2). C{ H} NMR (126 MHz, C D
with satellites, JPt-P ) 1836 Hz, JP-P ) 8.6 Hz), 12.67 (br s with
1
(C3), 36.7 (C7), 34.3 (C4 or C5), 34.2 (C4 or C5), 17.78 (dd, JP-C
195
satellites, JPt-P ) 4890 Hz). Pt NMR (64 MHz, C
-
6
D
6
or CD
4049 (dd, JPt-P ) 1697 Hz, 5181 Hz). F NMR (235 MHz, C
or CD Cl ): -149.2.
dppe)Pt(C
mmol) in minimum CH
6.0 mg, 0.012 mmol) in 0.2 mL of CD
8 formed immediately. After 2 h the clear solution was carefully
decanted off the solid. The solid was washed with minimum C
and dried in vacuo. Yield: 8.8 mg, 91%. Anal. Calcd (found) for
2 2
Cl ):
D
6 6
3
)
20.4 Hz, JP-C ) 3.8 Hz, PCH
Me), 8.2 (C2), 8.3 (PCH CH
101 MHz, C ): 14.42 (d with satellites, JPt-P ) 1566 Hz, JP-P
5 Hz), -0.04 (d with satellites, JPt-P ) 3485 Hz, JP-P ) 5 Hz).
2
Me), 14.9 (d, JP-C ) 21.9 Hz,
19
3
1
PCH
2
2
3 2 3
), 8.1 (PCH CH ). P NMR
2
2
(
6 6
D
(
7
H10OBF
3
) (8). A solution of dppe (5.0 mg, 0.012
Cl was added to an agitated solution of 3
Cl . A white precipitate of
)
3
1
2
2
P NMR (101 MHz, CD
2 2
Cl ): 13.92 (br s with satellites, JPt-P )
(
2
2
1
575 Hz), -0.40 (d with satellites, JPt-P ) 3600 Hz, JP-P ) 6
1
95
6 6
Hz). Pt NMR (64 MHz, C D ): -3883 (dd, JPt-P1 ) 1594 Hz,
6
H
6
JPt-P2 ) 3542 Hz).
(
PEt
a 10% solution, 0.029 mmol) was added dropwise to an agitated
solution of 3 (7.0 mg, 0.014 mmol) in 0.5 mL of C . After 5
3
)
2
Pt(C
7
H10OBF ) (6). From 3. PEt in hexane (50 µL of
3 3
1
C
33
H34BF
3
OP
Cl
Ph), 7.36 (m, 1H, Ph), 7.32 (m, 1H, Ph), 6.16 (s, 1H, H1), 2.45 (br
s, 1H, H7), 2.42 (s, 1H, H6), 2.31 (m, 2H, PCH ), 2.10 (m, 1H,
PCH ), 1.83 (m, 1H, PCH ), 1.62 (s, H3), 1.32 (m, 1H, H4), 1.28
(m, 1H, H5), 1.06 (m,1H, H7′), 0.79 (m, 1H, H4′), 0.77 (m, 1H,
2
Pt: C, 51.38 (51.53); H, 4.51 (4.44). H NMR (500
MHz, CD
2
2
): 7.79 (m, 4H, Ph), 7.71 (m, 4H, Ph), 7.52 (m, 10H,
6
D
6
min, the mixture was evaporated in vacuo. The resulting oily residue
was redissolved in toluene and the mixture evaporated to dryness
and left in vacuo for 2 h. This procedure was repeated for two or
three times until residual COD and PEt were eliminated and a
3
solid residue was obtained. The residue was washed with hexane
2
2
2
1
3
1
H2), 0.65 (t, JH-H ) 6.6 Hz, 1H, H5′). C{ H} NMR (75.5 MHz,
CD Cl ): 133.6 (s, Ph), 133.5 (s, Ph), 133.4 (s, Ph), 133.3 (s, Ph),
and dried in vacuo to give white solid 6. Yield: 8.4 mg, 95%.
2
2
Colorless single crystals for X-ray analysis were grown from a C
solution layered with hexane.
H
6 6
133.1 (s, Ph), 132.4 (s, Ph), 132.3 (s, Ph), 131.9 (d, JP-C ) 2.3 Hz,
Ph), 131.6 (d, JP-C ) 3.0 Hz, Ph), 130.8 (t, JP-C ) 2.3 Hz, Ph),
1
29.0 (s, Ph), 129.9 (s, Ph), 128.8 (t, JP-C ) 2.3 Hz, Ph), 128.7 (s,
From 5. BF
of 5 (6.8 mg, 0.013 mmol) in 1 mL of CH
removed in vacuo to give 6. Yield: 7.2 mg, 94%. Anal. Calcd
3
· Et
2
O (1.5 µL, 0.013 mmol) was added to a solution
Ph), 128.6 (s, Ph), 128.4 (s, Ph), 100.9 (s, C1), 43.3 (s, C6), 40.3
2
2
Cl . All volatiles were
1
3
(s, C3), 36.1 (s, C7), 31.9 (s, C4), 29.5 (dd, JP-C ) 43.0 Hz, JP-C
1
1 3
(
found) for C19
NMR (500 MHz, C
Hz, 1H, H7), 2.77 (d, 1H, H6), 2.14 (s, JPt-H ≈ 29 Hz, 1H, H3),
.80 (m, 1H, H4), 1.72 (m, 6H, PCH Me), 1.52 (m, 1H, H5), 1.35
H
40OBF
3
P
2
Pt: C, 37.45 (37.47); H, 6.56 (6.11). H
) 17.4 Hz, CH PPh ), 25.1 (dd, JP-C ) 34.0 Hz, JP-C ) 6 Hz,
2 2
195
6
D
6
): 6.65 (br s, 1H, H1), 2.94 (d, JH-H ) 4.0
CH
-4148 (dd, JPt-P ) 1729 Hz, 4684 Hz). P NMR (101 MHz,
CD Cl ): 48.35 (s, JPt-P ) 1697 Hz), 30.68 (s with satellites, JPt-P
2 2 2 2
PPh ), 24.1 (s, C2), 22.3 (s, C5). Pt NMR (64 MHz, CD Cl ):
3
1
1
2
2
2

A Family of Platinaoxetanes
Organometallics, Vol. 27, No. 6, 2008 1241
3
1
)
4730 Hz). P NMR (101 MHz, C
6
D
6
): 47.36 (s, JPt-P ) 1676
Hz), 30.99 (s, JPt-P ) 4584 Hz). F NMR (235 MHz, CD Cl ):
153.1 (s).
Me bpy)Pt(C
bipyridine (Me bpy) (2 mg, 0.01 mmol) in 0.3 mL of CD
added to an agitated solution of 3 (5.0 mg, 0.010 mmol) in 0.2 mL
of CD Cl . After about 10 min, a white precipitate of 9 began to
was washed with a small amount of benzene and dried in vacuo to
1
9
2
2
give yellow solid 10. Yield: 6.6 mg, 88%. Anal. Calcd (found) for
1
-
C H BF ON Pt: C, 46.70 (46.12); H, 5.34 (5.04). H NMR (500
2
5
34
3
2
(
2
7
H10OBF
3
) (9). A solution of 4,4′-dimethyl-2,2′-
Cl was
MHz, CD Cl ): 9.17 (m, 1H, bpy H6 or H6′), 8.74 (d, J
Pt-H
Hz, JH-H ) 6 Hz, 1H, bpy H6 or H6′), 7.94 (d, JH-H ) 2 Hz, 1H,
bpy H3 or H3′), 7.87 (d, JH-H ) 2 Hz, 1H, bpy H3 or H3′), 7.66
≈ 55
2
2
2
2
2
2
2
(
dd, JH-H ) 6 Hz, 2 Hz, 1H, bpy H5 or H5′), 7.37 (dd, JH-H ) 6
form. After 1 day at room temperature the solvent volume was
Hz, JH-H ) 2 Hz, 1H, bpy H5 or H5′), 5.92 (d, JH-H ) 6 Hz, 1H,
H1), 2.67 (d, JH-H ) 9.5 Hz, 1H, H7), 2.28 (d, JH-H ) 4 Hz, 1H,
H6), 2.26 (br s, 1H, H3), 1.68 (dd, JPt-H ≈ 54 Hz, JH2-H1 ) 6 Hz,
reduced to ∼0.2 mL and the solution was carefully decanted off
2 2
the product. The solid was washed with 0.2 mL of CH Cl and
dried in Vacuo. Yield: 6.3 mg, 94%. Anal. Calcd (found) for
JH2-H3 ) 2 Hz, H2), 1.51 (m, 2H, H4 and H4′), 1.44 (s, 1H, H5),
1
C
19
H22BF
3
2
ON Pt: C, 40.89 (40.28); H, 3.98 (3.83). H NMR (500
1
.42 (s, 9H, CH
3
), 1.41 (s, 9H, CH
3
), 1.15 (m, 1H, H7′), 0.91 (br
m, 1H, H5′). C{ H} NMR (126 MHz, CD Cl ): 163.9 (s, bpy),
63.2 (s, bpy), 157.6 (s, bpy), 153.3 (s, bpy), 151.8 (s, bpy), 150.8
s, bpy), 125.5 (s, bpy), 124.9 (s, bpy), 119.8 (s, bpy), 118.7 (s,
bpy), 102.0 (s, C1), 43.2 (s, C6), 40.9 (s,C3), 36.2 (s, C7), 36.1 (s,
CMe ), 35.9 (s, CMe ), 30.3 (s, CH ), 30.1(s, CH ), 29.9 (s, C4),
2.8 (s, C5), 3.8 (s, C2). Pt NMR (64 MHz, CD Cl ): -4042
s). F NMR (235 MHz, CD Cl ): -150.3 (s).
MHz, CD
2
Cl ): 9.10 (m, 1H, bpy H6 or H6′), 8.66 (d, JH-H ) 6
2
13
1
2
2
Hz, 1H, bpy H6 or H6′), 7.82 (s, 1H, bpy H3 or H3′), 7.76 (s, 1H,
bpy H3 or H3′), 7.45 (d, JH-H ) 5.5 Hz, 1H, bpy H5 or H5′), 7.18
1
(
(
d, JH-H ) 5.5 Hz, 1H, bpy H5 or H5′), 5.92 (d, JH-H ) 6 Hz, 1H,
H1), 2.67 (d, JH-H ) 9.5 Hz, 1H, H7, or H7′), 2.49 (s, 3H, CH ),
), 2.28 (d, JH-H ) 4.5 Hz, 1H, H6), 2.24 (br s,
3
3
3
3
3
2
1
1
(
-
.43 (s, 3H, CH
3
1
95
2
(
2
2
H, H3), 1.66 (dd, JH2-H1 ) 6 Hz, JH2-H3 ) 2.5 Hz, H2), 1.52 (m,
H, H4), 1.42 (s, 1H, H5), 1.26 (d, JH-H ) 3 Hz, 1H, H4′), 1.15
1
9
2
2
195
m, 1H, H7′), 0.90 (br, m, 1H, H5′). Pt NMR (64 MHz, CD
2
Cl
2
):
1
9
Acknowledgment. Support from the Chemical Sciences,
2 2
4045 (s). F NMR (235 MHz, CD Cl ): -150.4.
Geosciences, and Biosciences Division, Office of Basic
Energy Sciences, Offices of Science, U.S. Department of
Energy (DE-FG02-88ER13880), is gratefully acknowledged.
A grant from the National Science Foundation (9221835)
provided a portion of the funds for the purchase of the NMR
equipment. We thank Dr. C. Barnes for X-ray data collection
and analysis and Patrick Markway and Michael Stever for
their studies of the interaction of isobutylene and norbornene
oxide with Pt(0) complexes.
t
(
Bu
2
bpy)Pt(C
7
H
10OBF
3
) (10). A solution of 3 (5.6 mg, 0.012
mmol) in 0.4 mL of C
6
D
6
was added to an agitated solution of
t
4
,4′-di-tert-butyl-2,2′-bipyridine (Bu
in minimum CH Cl
vacuo. The resulting oily residue was redissolved in toluene/CH
and the volatiles were removed in vacuo, after which the residue
was left in vacuo for 2 h. This procedure was repeated for two or
three times until residual COD was removed. The remaining solid
2
bpy) (3.1 mg, 0.012 mmol)
2
2
. After 2 days, the volatiles were removed in
2
Cl ,
Supporting Information Available: Details of crystal structure
determination (cif files). This materials is available free of charge
via the Internet at http://pubs.acs.org.
2
OM7010479