Platinum and palladium imido and oxo complexes with small natural bite angle diphosphine ligands

Article abstract of DOI:10.1021/ic025987f

Treatment of L₂MCl₂ (M = Pt, Pd; L₂ = Ph₂PCMe₂PPh₂ (dppip), Ph₂PNMePPh₂ (dppma)) with AgX (X = OTf, BF₄, NO₃) in wet CH₂Cl₂ yields the dinuclear dihydroxo complexes [L₂M(μ-OH)]₂(X)₂, the mononuclear aqua complexes [L₂M(OH₂)₂](X)₂, the mononuclear anion complexes L₂MX₂, or mixtures of complexes. Addition of aromatic amines to these complexes or mixtures gives the dinuclear diamido complexes [L₂Pt(μ-NHAr)]₂(BF₄)₂, the mononuclear amine complexes [L₂M(NH₂Ar)₂](X)₂, or the dinuclear amido-hydroxo complex [Pt₂(μ-OH)(μ-NHAr)(dppip)₂] (BF₄)₂. Deprotonation of the Pd and Pt amine or diamido complexes with M′N(SiMe₃)₂ (M′ = Li, Na, K) gives the diimido complexes [L₂M(μ-NAr)]₂ associated with M′ salts. Structural studies of the Li derivatives indicate association through coordination of the imido nitrogen atoms to Li⁺. Deprotonation of the amido-hydroxo complex gives the imido-oxo complex [Pt₂(μ-O)(μ-NAr)(dppip)₂]· LiBF₄·LiN(SiMe₃)₂, and deprotonation of the dppip Pt hydroxo complex gives the dioxo complex [Pt(μ-O)(dppip)]₂·LiN(SiMe₃) ₂·2LiBF₄.

Full text of DOI:10.1021/ic025987f

Inorg. Chem. 2003, 42, 1282−1295
Platinum and Palladium Imido and Oxo Complexes with Small Natural
Bite Angle Diphosphine Ligands
U. Anandhi, Todd Holbert, Dennis Lueng, and Paul R. Sharp*
125 Chemistry, UniVersity of Missouri, Columbia, Missouri 65211
Received August 29, 2002
Treatment of L2MCl2 (M ) Pt, Pd; L2 ) Ph2PCMe2PPh2 (dppip), Ph2PNMePPh2 (dppma)) with AgX (X ) OTf, BF ,
4
NO ) in wet CH Cl2 yields the dinuclear dihydroxo complexes [L2M(µ-OH)]2(X)2, the mononuclear aqua complexes
3
2
[L2M(OH ) ](X)2, the mononuclear anion complexes L2MX , or mixtures of complexes. Addition of aromatic amines
2 2
2
to these complexes or mixtures gives the dinuclear diamido complexes [L2Pt(µ-NHAr)]2(BF ) , the mononuclear
4 2
amine complexes [L2M(NH Ar)2](X)2, or the dinuclear amido−hydroxo complex [Pt2(µ-OH)(µ-NHAr)(dppip)2](BF ) .
2
4 2
Deprotonation of the Pd and Pt amine or diamido complexes with M′N(SiMe3)2 (M′ ) Li, Na, K) gives the diimido
complexes [L2M(µ-NAr)]2 associated with M′ salts. Structural studies of the Li derivatives indicate association through
coordination of the imido nitrogen atoms to Li+. Deprotonation of the amido−hydroxo complex gives the imido−oxo
complex [Pt2(µ-O)(µ-NAr)(dppip)2]‚LiBF ‚LiN(SiMe3)2, and deprotonation of the dppip Pt hydroxo complex gives
4
the dioxo complex [Pt(µ-O)(dppip)]2‚LiN(SiMe3)2‚2LiBF .
4
Introduction
complexes for all of these metals except Pd.4 Application of
successful techniques for Pt to the synthesis of the Pd
analogues have generally failed, and analogous Pd oxo and
imido complexes have remained elusive. Even for Pt, imido
complexes have been difficult to obtain. Although a series
of oxo complexes containing ancillary phosphine ligands
have been prepared,5 analogous imido complexes can only
be isolated in the special case of the dppm ligand.6 The
synthesis of the dppm imido complexes is complicated by
initial deprotonation of the methylene bridge of the dppm
ligand (Scheme 1). As a result, the final deprotonation of
the amido ligands is from a neutral complex instead of a
dicationic complex. The absence of positive charge decreases
Interest in the chemistry of late transition metals bonded
to simple anionic oxygen- and nitrogen-containing ligands
such as aryloxo, alkoxo, hydroxo, amido, oxo, and imido
ligands derives from several areas including chemotherapy
drugs,1 enzyme modeling,2 and various catalytic and sto-
ichiometric processes.3 Oxo and imido complexes are of
particular interests since there is a scarcity of such complexes,
especially in comparison to the early transition metals, and
because of the perception that such scarcity implies high and/
or unusual reactivity for these complexes.3
Our efforts have been directed at the synthesis of oxo and
imido complexes of the heavier late transition metals Rh,
Ir, Pd, Pt, and Au.3b We have reported oxo and imido
(3) Reviews: (a) Cinellu, M. A.; Minghetti, G. Gold Bull. 2002, 35, 11-
20. (b) Sharp, P. R. J. Chem. Soc., Dalton Trans. 2000, 2647-2657.
(c) Sharp, P. R. Comments Inorg. Chem. 1999, 21, 85-114. (d) Oro,
L. A.; Ciriano, M. A.; Tejel, C.; Shi, Y.-M.; Modrego, J. Metal Clusters
Chem. 1999, 1, 381-398. (e) Brunet, J.-J. Gazz. Chim. Ital. 1997,
127, 111-118. (f) Bergman, R. G. Polyhedron 1995, 14, 3227-3237.
(g) Wigley, D. E. Prog. Inorg. Chem. 1994, 42, 239-482. (h) Fryzuk,
M. D.; Montgomery, C. D. Coord. Chem. ReV. 1989, 95, 1-40. (i)
Power, P. P. Comments Inorg. Chem. 1989, 8, 177-202. (j) West, B.
O. Polyhedron 1989, 8, 219-274. (k) Bryndza, H. E.; Tam, W. Chem.
ReV. 1988, 88, 1163-1188. (l) Griffith, W. P. Coord. Chem. ReV.
1970, 5, 459-517.
(4) The only reported Pd imido complex is trimeric [Pd3(NHPh)(NPh)2-
(PEt3)3]+, unexpectedly isolated in poor yield from the reaction of
(PEt3)2PdCl2 with [PhN3NHCH2CH2NH]2-: Lee, S. W.; Trogler, W.
C. Inorg. Chem. 1990, 29, 1099-1102.
(5) Li, J. J.; Li, W.; Sharp, P. R. Inorg. Chem. 1996, 35, 604-613.
(6) Li, J. J.; Li, W.; James, A. J.; Holbert, T.; Sharp, T. P.; Sharp, P. R.
Inorg. Chem. 1999, 38, 1563-1572.
* To whom correspondence should be addressed. E-mail: SharpP@
Missouri.edu.
(1) Reviews: (a) Berners-Price, S. J.; Appleton, T. G. Platinum-Based
Drugs Cancer Ther. 2000, 3-35. (b) Sherman, S. E.; Lippard, S. J.
Chem. ReV. 1987, 87, 1153-1181. (c) Platinum, Gold, and Other
Metal Chemotherapeutic Agents: Chemistry and Biochemistry; Lip-
pard, S. J., Ed.; American Chemical Society: Washington, DC, 1983.
(2) Reviews: (a) Que, L., Jr.; Tolman, W. B. Angew. Chem., Int. Ed.
2002, 41, 1114-1137. (b) Holland, P. L.; Tolman, W. B. Coord. Chem.
ReV. 1999, 192, 855-869. (c) Klinman, J. P. Chem. ReV. 1996, 96,
2541-2562. (d) Solomon, E. I.; Sundaram, U. M.; Machonkin, T. E.
Chem. ReV. 1996, 96, 2563-2605. (e) Holm, R. H.; Kennepohl, P.;
Solomon, E. I. Chem. ReV. 1996, 96, 2239-2314. (f) Solomon, E. I.;
Tuczek, F.; Root, D. E.; Brown, C. A. Chem. ReV. 1994, 94, 827-
856. (g) Karlin, K. D.; Tyeklar, Z. AdV. Inorg. Biochem. 1994, 9, 123-
172. (h) Solomon, E. I.; Baldwin, M. J.; Lowery, M. D. Chem. ReV.
1992, 92, 521-542. (i) Karlin, K. D.; Gultneh, Y. Prog. Inorg. Chem.
1987, 35, 219-328.
1282 Inorganic Chemistry, Vol. 42, No. 4, 2003
10.1021/ic025987f CCC: $25.00 © 2003 American Chemical Society
Published on Web 01/16/2003

Platinum and Palladium Imido and Oxo Complexes
Scheme 1
the acidity of the amido group N-H, and the final depro-
tonation to the anionic imido complex requires the strong
base MeLi. In this report we present our results on a new
series of Pt and Pd complexes with small natural bite angle
diphosphine ligands related to dppm but which do not contain
acidic hydrogen atoms. These smaller natural bite angle
diphosphine ligands have allowed the facile preparation of
a number of new Pt and Pd complexes including imido
complexes for both Pt and Pd.
by 195Pt satellites with JPt-P ) 3483 (dppma) or 3125 (dppip)
Hz. H NMR spectra of 1 show bidentate phosphine ligand
1
peaks in which the methyl groups appear as triplets with
3JP-H ) 12.5 (dppma) or 15.0 (dppip) Hz. In addition to the
phosphine ligand signals, signals for the bridged OH groups
are observed at 3.02 (dppma) and 2.02 (dppip) ppm.
The successful formation of the hydroxo complexes
depends on the amount of water present in the reaction
mixture. In the case of L2 ) dppip, if water is present in too
low an amount, the 31P NMR spectrum of the reaction
mixture and the isolated complex show an impurity peak at
-29.1 ppm with a JPt-P coupling constant of 3140 Hz. The
31P NMR spectrum of the reaction mixture when too much
water is present shows a peak at -32.0 ppm (JPt-P ) 3185
Hz). This coupling constant is 60 Hz more than the bridged
hydroxo complex, and we attribute this signal to diaquo
complex [(dppip)Pt(OH2)2](BF4)2.
Results
Reactions of L2PtCl2 with AgBF4. The hydroxo com-
plexes [L2Pt(µ-OH)2]2(BF4)2 (1) (L2 ) Ph2PN(Me)PPh2
(dppma), Ph2PC(Me2)PPh2 (dppip)) are prepared by treating
L2PtCl2 with AgBF4 (eq 1). The reactions are similar to those
reported for related Pt(II) and Pd(II) phosphine complexes7
including the closely related dppm complexes.5
In the case of L2 ) dppma, other complexes also form if
water is not present in the correct amount. 31P NMR spectra
of the reaction mixtures and the isolated solids show
additional broad peaks at 9.0 and 8.0 ppm when too much
or too little water is present. Purification of the mixtures, to
obtain selectively the hydroxo complex, was not successful.
The nitrate complex Pt(dppma)(NO3)2 (2), useful for the
preparation of Pt mononuclear diamine complexes (see
below), is obtained by treatment of PtCl2(dppma) with
AgNO3 in dry CH2Cl2 (eq 2). The 31P NMR spectrum of 2
shows an upfield singlet flanked by Pt satellites with larger
coupling constants as compared to the chloro complexes. The
1H NMR spectrum shows only peaks for the dppma ligand.
Single-crystal X-ray analysis shows the structure given in
Figure 1.8 An abbreviated summary of crystal data and data
collection and processing is given in Table 1. Selected bond
distances and angles are listed in Table 3.
31P NMR spectra of the reaction mixtures and isolated 1
show a singlet at 10.5 (dppma) or -30.5 (dppip) ppm flanked
(7) (a) Bushnell, G. W.; Dixon, K. R.; Hunter, R. G.; McFarland, J. J.
Can. J. Chem. 1972, 50, 3694. (b) Rochon, F. D.; Guay, F. Acta
Crystallogr., Sect. C 1987, 43, 43. (c) Trovo, G.; Bandoli, G.;
Casellato, U.; Corain, B.; Nicolini, M.; Longata, B. Inorg. Chem. 1990,
29, 4616-4621. (d) Pisano, C.; Consiglio, G.; Sironi, A.; Moret, M.
J. Chem. Soc., Chem. Commun. 1991, 421-3. (e) Fallis, S.; Anderson,
G. K.; Rath, N. P. Organometallics 1991, 10, 3180-3184. (f) Ericson,
V.; Lovqvist, K.; Noren, B.; Oskarsson, A. Acta Chem. Scand. 1992,
46, 854. Ganguly, S.; Mague, J. T.; Roundhill, D. M. Inorg. Chem.
1992, 31, 3831-3835. (g) Rochon, F. D.; Melanson, R.; Morneau, A.
Magn. Reson. Chem. 1992, 30, 697. (h) Bandini, A. L.; Banditelli,
G.; Demartin, F.; Manassero, M.; Minghetti, G. Gazz. Chim. Ital. 1993,
123, 417-423. (i) Burgarcic, Z.; Lovqvist, K.; Oskarsson, A. Acta
Crystallogr., Sect. C 1994, 50, 1028. (j) Miyamoto, T. K. Chem. Lett.
1994, 1971. (k) Marvin, J. R.; Abbott, E. H. Inorg. Chim. Acta 1996,
247, 267-271. (l) Strukul, G.; Varagnolo, A.; Pinna, F. J. Mol. Catal.,
A 1997, 117, 413-423. (m) Gavagnin, R.; Cataldo, M.; Pinna, F.;
Strukul, G. Organometallics 1998, 17, 661-667. (n) Fujii, A.;
Hagiwara, E.; Sodeoka, M. J. Am. Chem. Soc. 1999, 121, 5450-5458.
(o) Kannan, S.; James, A. J.; Sharp, P. R. Polyhedron 2000, 19, 155-
163.
Reactions of L2PdCl2 with AgX. Analogous reactions of
the Pd complexes PdCl2L2 give different products from those
Inorganic Chemistry, Vol. 42, No. 4, 2003 1283

Anandhi et al.
Table 1. Crystallographic and Data Collection Parameters for 2, Pd(OTf)2(dppma), and 7a
2
Pd(OTf)2(dppma)
7 (L2 ) dppip, X ) OTF)
7 (L2 ) dppma, X ) OTF)
formula
fw
space group
a, Å
b, Å
c, Å
C25H23N3O6P2Pt
718.49
P1h
C27H23F6NO6P2PdS2
803.92
P1
C43H44F6N2O6P2PdS2‚CH2Cl2
C41H41F6N3O6P2PdS2‚2C7H8
1116.19
P21/c
1202.50
P2/n
11.091(3)
14.376(3)
18.013(4)
89.970(4)
77.020(4)
73.632(4)
2679.3(10)
4
9.048(3)
9.051(3)
11.395(3)
97.873(5)
102.687(5)
116.755(4)
782.6(4)
1
12.678(2)
12.1036(19)
31.804(5)
90
91.659(3)
90
4878.4(13)
4
1.52
11.2832(11)
12.4429(12)
20.1851(19)
90
100.305(2)
90
2788.2(5)
2
1.43
R, deg
â, deg
γ, deg
V, Å3
Z
d
calc, g/cm3
1.78
5.40
0.0767, 0.1940
1.71
0.906
0.0492, 0.1583
µ, mm-1
0.712
0.0476, 0.1029
0.536
0.0556, 0.1327
R1,b wR2c
a λ ) 0.710 70 Å (Mo), T ) -100 °C. b R1 ) (Σ||Fo| - |Fc||)/Σ|Fo|. c wR2 ) [(Σw(Fo - Fc )2)/Σw(Fc )2]1/2
Table 2. Crystallographic and Data Collection Parameters for 9-11a
.
2
2
2
9
10 (M ) Pt)
10 (M ) Pd)
11 (M ) Pt)
11 (M ) Pd)
formula
C68H70BF4LiN4O2P4Pt2‚
C74H84LiN3P4Pt2Si2‚
4C4H8O
1881.04
C74H84LiN3P4Pd2Si2‚
4C4H8O
1703.66
C66H64LiN5O3P4Pt2‚
C66H64LiN5O3P4Pd2‚
d
d
3C4H10O2
1853.45
P4/ncc
24.3639(18)
24.3639(18)
28.208(3)
90
C4H8O‚Cn
C4H8O‚Cn
fw
1568.33e
P21/m
11.4635(7)
24.1305(14)
13.6535(8)
90
1390.95e
P21/m
11.5079(10)
24.026(2)
13.7686(12)
90
space group
a, Å
b, Å
P1h
P1h
13.1670(17)
15.0144(19)
24.087(3)
89.121(2)
85.488(2)
67.937(2)
4398.9(10)
2
13.146(6)
14.948(7)
24.173(12)
89.291(8)
85.350(8)
67.986(8)
4388(4)
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
90
90
16744(2)
8
1.470
100.6360(10)
90
100.951(2)
90
3711.9(4)
2
3737.5(6)
2
2
d
calc, g/cm3
1.420
3.326
0.0315, 0.0728
1.289
0.560
0.0766, 0.1739
1.403e
1.236e
µ, mm-1
3.477
0.0441, 0.0989
3.897e
0.612e
R1,b wR2c
0.0401, 0.0781
0.0870, 0.1556
2
2
2
a λ ) 0.710 70 Å (Mo), T ) -100 °C. b R1 ) (Σ||Fo| - |Fc||)/Σ|Fo|. c wR2 ) [(Σw(Fo - Fc )2)/Σw(Fc )2]1/2
.
d Cn represents unresolved disordered
solvent of crystallization. e Calculated without unresolved solvent of crystallization.
workup, yellow products that give broad peaks in their 31P
NMR spectra. 1H NMR spectra show dppma peaks and broad
peaks attributed to OH or H2O groups. Elemental analyses
vary from sample to sample suggesting that these products
are exchanging mixtures of complexes such as [Pd(OH2)2-
(dppma)](X)2, [Pd(OH2)(X)(dppma)](X), Pd(X)2(dppma), and
[Pd(µ-OH)(dppma)]2(X)2. Layering the CH2Cl2 reaction
mixture (X ) OTf) with Et2O yields a small amount of
crystals, which X-ray analysis shows to be Pd(OTf)2-
(dppma).9 A drawing of the complex is shown in Figure 2.
An abbreviated summary of crystal data and data collection
and processing is given in Table 1. Selected bond distances
and angles are listed in Table 4.
Figure 1. ORTEP drawing (50% probability ellipsoids) of one of two
nearly identical independent molecules of Pt(NO3)2(dppma) (2).
An analogous reaction of PdCl2(dppma) with AgNO3
clearly gives a mixture of products. The 31P NMR spectrum
Table 3. Selected Distances (Å) and Angles (deg) for Pt(NO3)(dppma)
(2)a
(8) Other structurally characterized Pt(II) and Pd(II) nitrate phosphine
complexes: (a) Countryman, R.; McDonald, W. S. Acta Crystallogr.,
Sect. B 1977, 33, 3580. (b) Jones, C. J.; McCleverty, J. A.; Rothin,
A. S.; Adams, H.; Bailey, N. A. J. Chem. Soc., Dalton Trans. 1986,
2055. (c) Suzuki, Y.; Miyamoto, T. K.; Ichida, H. Acta Crystallogr.,
Sect. C 1993, 49, 1318. (d) Gorla, F.; Togni, A.; Venanzi, L. M.;
Albinati, A.; Lianza, F. Organometallics 1994, 13, 1607. (e) Rath, N.
P.; Stockland, R. A., Jr.; Anderson, G. K. Acta Crystallogr., Sect. C
1999, 55, 494. (f) Redwine, K. D.; Wilson, W. L.; Moses, D. G.;
Catalano, V. J.; Nelson, J. H. Inorg. Chem. 2000, 39, 3392. (g) Gul,
N.; Nelson, J. H. Organometallics 2000, 19, 91. (h) Arendse, M. J.;
Anderson, G. K.; Rath, N. P. Acta Crystallogr., Sect. C 2001, 57,
237. (i) Fernandez, D.; Sevillano, P.; Garcia-Seijo, M. I.; Castineiras,
A.; Janosi, L.; Berente, Z.; Kollar, L.; Garcia-Fernandez, M. E. Inorg.
Chim. Acta 2001, 312, 40.
Pt1-P1
Pt1-P2
Pt1-O1
Pt1-O4
2.206(4)
2.205(3)
2.100(10)
2.089(10)
Pt2-P3
Pt2-P4
Pt2-O7
Pt2-O10
2.200(3)
2.216(3)
2.096(8)
2.078(9)
P2-Pt1-P1
O4-Pt1-O1
72.41(13)
76.4(4)
P3-Pt2-P4
O10-Pt2-O7
72.28(13)
76.0(3)
a Metrical parameters are given for both independent molecules.
for Pt demonstrating a reduced tendency to hydroxo forma-
tion in the Pd complexes. Treatment of PdCl2(dppma) with
AgX (X ) OTf, BF4) and water in CH2Cl2 yields, after
1284 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
Unlike PdCl2(dppma), PdCl2(dppip) gives a single product
when treated with AgOTf and small amounts of water in
CH2Cl2. The pale yellow triflate-coordinated complex Pd-
(OTf)2(dppip) (3) is isolated in 80% yield (eq 4) and gives
satisfactory elemental analysis. The 31P NMR spectrum of
isolated 3 displays a single sharp peak at -16.5 ppm. The
1H NMR spectrum shows peaks for the phosphine ligand
but no OH peaks. The related complex Pd(OTf)2(dppp)9g has
been reported to readily exchange the triflate anions for water
molecules under similar conditions.10
Figure 2. ORTEP drawing (50% probability ellipsoids) of Pd(OTf)2-
(dppma).
Table 4. Selected Distances (Å) and Angles (deg) for
Pd(OTf)2(dppma)
Pd1-O1
Pd1-O4
Pd1-P2
Pd1-P1
S1-O6
2.134(8)
2.146(7)
2.222(2)
2.228(3)
1.416(8)
S1-O5
S1-O4
S2-O2
S2-O3
S2-O1
1.426(8)
1.460(8)
1.408(8)
1.443(7)
1.492(8)
Platinum Amido and Amine Complexes. Reactions of
aromatic amines with 1 and 2 produce bridged Pt diamido
complexes or mononuclear diamine complexes depending
on the Pt precursor, the amine, and the reaction conditions.
The reaction of 1 (L2 ) dppma), with 4-toluidine at ambient
temperature yields the diamido complex [L2Pt(µ-NHAr)]2-
(BF4)2 (4) (Ar ) 4-tol, L2 ) dppma, eq 5). A similar reaction
of 1 (L2 ) dppip) with aniline yields diamido complex 4
(Ar ) Ph, L2 ) dppip), but with 4-toluidine, 4 (Ar ) 4-tol,
L2 ) dppip) is formed only upon refluxing the reaction
mixture at 50 °C (eq 5).
O1-Pd1-O4
O1-Pd1-P2
O4-Pd1-P2
79.7(3)
104.3(2)
176.1(3)
O1-Pd1-P1
O4-Pd1-P1
P2-Pd1-P1
175.0(2)
104.7(2)
71.39(10)
of the reaction mixture and the isolated lemon yellow solid
shows two sets of doublets at 32.7 and 26.5 ppm (2JP-P
)
21 Hz), and a singlet at 29.1 ppm. The two sets of doublets
and the singlet observed in the 31P NMR spectrum may be
attributed to [Pd(OH2)(NO3)(dppma)](NO3) and [Pd(NO3)2-
(dppma)], respectively. Presumably, observation of the
individual peaks is due to slower exchange rates than for
the OTf- and BF4- derivatives as a result of stronger bonding
of the nitrate ion to the Pd center. Conditions for isolating
single products in these reactions are under investigation and
will be reported separately. Meanwhile, these product
mixtures, referred to as “L2Pd(X)2” (eq 3), are useful
precursors for the preparation of mononuclear Pd diamine
complexes (see below).
1H NMR signals for the NH groups of 4 are observed as
broad singlets or triplets between 4 and 5 ppm. These shifts
are comparable to those observed for the dppm analogues
but are at lower field than larger natural bite angle diphos-
phine analogues (dppe, dppp, dppb).6 Like the dppm
analogues, all 3 derivatives of 4 show evidence of hindered
rotation about the N-Ar bond on the NMR time scale. In
the absence of rotation, the ortho and meta hydrogen atoms
of the aryl rings are all inequivalent and 4 peaks are expected.
With rapid rotation the two meta hydrogen atoms become
equivalent, the two ortho hydrogen atoms become equivalent,
and only two peaks are expected. The dppip derivative with
Ar ) 4-tol shows two peaks at 50 °C (300 MHz) for the tol
aromatic peaks. These two peaks are shifted upfield from
(9) Other structurally characterized Pt(II) and Pd(II) triflate phosphine
complexes: (a) Appelt, A.; Ariaratnam, V.; Willis, A. C.; Wild, S. B.
Tetrahedron: Asymmetry 1990, 1, 9-12. (b) Carr, N.; Mole, L.; Orpen,
A. G.; Spencer, J. L. J. Chem. Soc., Dalton Trans. 1992, 2653. (c)
Bennett, B. L.; Birnbaum, J.; Roddick, D. M. Polyhedron 1995, 14,
187. (d) Bennett, B. L.; Birnbaum, J.; Roddick, D. M. Polyhedron
1995, 14, 187. (e) Aizawa, S.-I.; Yagu, T.; Kato, K.; Funahashi, S.
Anal. Sci. 1995, 11, 557. (f) Stang, P. J.; Cao, D. H.; Saito, S.; Arif,
A. M. J. Am. Chem. Soc. 1995, 117, 6273. (g) Stang, P. J.; Cao, D.
H.; Poulter, G. T.; Arif, A. M. Organometallics 1995, 14, 1110-
1114. (h) Sperrle, M.; Gramlich, V.; Consiglio, G. Organometallics
1996, 15, 5196-5201. (i) Vicente, J.; Arcas, A.; Bautista, D.; Jones,
P. G. Organometallics 1997, 16, 2127. (j) Campora, J.; Lopez, J. A.;
Palma, P.; Valerga, P.; Spillner, E.; Carmona, E. Angew. Chem., Int.
Ed. 1999, 38, 147. (k) Annibale, G.; Bergamini, P.; Bertolasi, V.;
Cattabriga, M.; Ferretti, V. Inorg. Chem. Commun. 2000, 3, 303. (l)
Dahlenburg, L.; Mertel, S. J. Organomet. Chem. 2001, 630, 221. (m)
Xia, A.; Sharp, P. R. Polyhedron 2002, 21, 1305-1310.
Inorganic Chemistry, Vol. 42, No. 4, 2003 1285

Anandhi et al.
Chart 1
the usual aromatic region presumably by the “ring current”
effect of “sandwiching” dppip phenyl rings. One is a sharp
doublet at 5.71 ppm, and the other is a broad peak at 6.28
ppm. As the temperature is lowered, the broad peak becomes
broader and reaches the coalescence point at 10 °C. Similarly,
the sharp doublet becomes broader but does not reach the
coalescence point until -10 °C. At -70 °C, 4 doublets are
observed where the sharp doublet at 50 °C has resolved into
two closely spaced doublets at 5.67 and 5.76 ppm and the
broad peak at 50 °C has resolved into two widely spaced
doublets at 5.36 and 6.36 ppm. This gives ∆Gq values for
the rotation process of 53.8 and 55.4 kJ/mol for an average
value of 55(1) kJ/mol.11 Similar behavior is observed for
the dppma derivative, and ∆Gq values of 58.9 and 61.9 kJ/
mol (average value of 60(2) kJ/mol) are calculated. Detailed
variable-temperature spectra were not recorded for the dppip
Ph derivative. Comparison of spectra in CDCl3 and CD2Cl2
indicate slower rotation rates in CDCl3 than in CD2Cl2. This
was also found for the dppm analogues.6
smaller JPt-P values are consistent with the greater donor
strength of the amido ligands over the hydroxo ligand.14
With more sterically hindered 2,6-dimethylaniline, the
reaction with 1 (L2 ) dppip) gives only the white mixed
amido-hydroxo complex [Pt2(µ-OH)(µ-NHAr)(dppip)2]-
(BF4)2 (5) (eq 6). No diamido complex is obtained even upon
refluxing the reaction mixture with excess 2,6-dimethylani-
line. The replacement of the second hydroxo group is pre-
sumably sterically inhibited as observed in related systems.6
1H NMR spectra of 4 also show signals for the dppip and
dppma ligands. The phenyl groups are multiplets from 7.0
to 8.2 ppm, and the methyl groups are triplets (3JHP ) 15.0
and 12.5 Hz) at ca. 1 ppm (dppip) and just above 2 ppm
(dppma). The dppip derivatives show two overlapping triplets
for the methyl groups. This most likely indicates that 4, at
least for the dppip derivatives, has a syn orientation of the
Ar groups (Chart 1) since this would give inequivalent dppip
methyl groups. The alternate anti isomer has C2 symmetry
relating the two methyl groups, and only one triplet signal
would be expected. The anti isomer could still give rise to
two signals if the complex is folded at the shared N--N edge
of the two square planar Pt centers. However, in general the
energy difference between folded and planar structures is
small in d8 systems12 and a static folded structure in solution
is unlikely. Syn and anti isomers have been observed in
solution with related systems.6,13
31P NMR spectra of the amido-hydroxo complex 5 show
two sets of doublets, one for the phosphorus trans to the
OH group and one for the phosphorus trans to the NHAr
group. The small P-P coupling of ∼60 Hz is consistent with
a cis-phosphine geometry at the Pt centers.14 Each phosphine
doublet displays the expected 195Pt satellites. The upfield
doublet shows larger P-Pt coupling than the downfield
doublet, and the coupling constant is similar to that of the
starting hydroxo complex. Since coupling constants depend
on the donor strength of the ligand trans to the phosphine
atom, this signal is assigned to the phosphorus atom trans
1
to the OH group.14 The H NMR spectrum of the complex
shows two singlets at 2.34 and 4.61 ppm for the OH and
NH groups. The amido ligand methyl groups resonate as two
singlets at 3.32 and 1.64 ppm. The two meta protons resonate
as doublets at 6.02 and 5.59 ppm, and the para proton
resonates as a triplet at 5.95 ppm. The appearance of two
signals for the amido methyl groups and the amido meta
hydrogen atoms indicates the absence of rotation about the
N-C bond of the amido ligand (on the NMR time scale).
The dppip methyl groups are observed as two triplets (1.37
and 0.76 ppm) consistent with the low symmetry of the
complex and the configuration at the nitrogen center.
31P NMR spectra for 4 show downfield shifts and smaller
JPt-P values compared to the parent hydroxo complexes. The
(10) We assume that the indicated water addition of 2.0 and 10 mL in this
report is in error and that the units should be µL and not mL.
(11) Lukehart, C. M. Fundamental Transition Metal Organometallic
Chemistry; Brooks/Cole: Monterey, CA, 1985; p 200.
(12) (a) Summerville, R. H.; Hoffmann, R. J. Am. Chem. Soc. 1976, 98,
7240. (b) Au´llon, G.; Ujaque, G.; Lledo´s, A.; Alvarez, S.; Alemany,
P. Inorg. Chem. 1998, 37, 804-813. (c) Au´llon, G.; Ujaque, G.;
Lledo´s, A.; Alvarez, S. Chem.sEur. J. 1999, 5, 1391-1410.
(13) (a) Brunet, J.-J.; Commenges, G.; Neibecker, D.; Philippot, K.;
Rosenberg, L. Inorg. Chem. 1994, 33, 6373-6379. (b) Okeya, S.;
Yoshimatsu, H.; Nakamura, Y.; Kawaguchi, S. Bull. Chem. Soc. Jpn.
1982, 55, 483-491. (c) Villanueva, L. A.; Abboud, K. A.; Boncella,
J. A. Organometallics 1994, 13, 3921-3931. (d) Driver, M. S.;
Hartwig, J. F. J. Am. Chem. Soc. 1996, 118, 4206-4207.
(14) (a) Pidcock, A.; Richards, R. E.; Venanzi, L. M. J. Chem. Soc. A
1966, 1707-10. (b) Allen, F. H.; Pidcock, A. J. Chem. Soc. A 1968,
2700. (c) Hartley, F. R. The Chemistry of Platinum and Palladium;
Applied Science: Oxford, U.K., 1973. (d) Appleton, T. G.; Clark, H.
C.; Manzer, L. E. Coord. Chem. ReV. 1973, 10, 335.
1286 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
The mononuclear diamine complex [L2Pt(NH2Ar)2](NO3)2
(6) (L2 ) dppma, Ar ) 2,6-xylyl) is isolated from the
reaction of [L2Pt(NO3)2] with 2,6-dimethylaniline (eq 7).
The 31P NMR spectrum of the reaction mixture shows a
broad peak at 13.6 ppm with JPt-P ) 3222 Hz, whereas the
isolated solid shows a sharp peak at 3.0 ppm with JPt-P
)
3810 Hz. The small value of the Pt-P coupling constant
(3222 Hz) for the reaction mixture suggests the presence of
a strong-donor amido ligand trans to the P center.14 The
excess 2,6-dimethylaniline present in the reaction mixture
is probably responsible for this behavior where reversible
(broadness of the NMR signal) deprotonation of 6 by the
aniline gives an amido ligand. However, precipitation must
favor 6 and once 6 is isolated free from the excess
2,6-dimethylaniline there is no deprotonation. The 1H NMR
spectrum of isolated 6 shows peaks corresponding to the
amine methyl groups (singlet at 2.16 ppm), the meta protons
(doublet at 6.89 ppm), and the para protons (triplet at 6.59
ppm). The NH2 signal is observed at 4.62 ppm.
Figure 3. ORTEP drawings (50% probability ellipsoids) of [Pd(NH2-4-
tol)2L2](OTf)2 (7) (L2 ) dppip (a), dppma (b); X ) OTf). Labeled and
unlabeled atoms in (b) are related by a 2-fold axis passing through Pd1
and N1.
Table 5. Selected Distances (Å) and Angles (deg) for
[Pd(NH2-4-tol)2L2](OTf)2 (7) (L2 ) dppip, dppma; X ) OTf)
L2 ) dppip
L2 ) dppma
Pd1-N1
Pd1-N2
Pd1-P1
Pd1-P2
N1-C51
N2-C61
N2-C14
2.152(3)
2.157(3)
2.2596(9)
2.2671(9)
1.447(4)
1.440(4)
2.135(4)
2.2478(16)
Pd Amine Complexes. Addition of 4-toluidine to the
mixtures “Pd(dppma)X2” (X ) BF4, OTf) or the dppip triflate
complex Pd(dppip)(OTf)2 (3) yields the mononuclear Pd
1.450(7)
N1-Pd1-N2
N2-Pd1-N2
P1-Pd1-P2
P1-Pd1-P1
83.56(11)
73.02(3)
1
diamine complexes [L2Pd(NH2-4-tol)2](X)2 (7) (eq 8). H
86.9(2)
NMR spectra of the complexes in CDCl3 show NH2 peaks
at 5.85-6.28 ppm. 31P NMR spectra show sharp singlets.
The solid-state structures of 7 (L2 ) dppma, dppip; X )
OTf) were determined by single-crystal X-ray diffraction.15
Drawings of the structures, illustrating the hydrogen bonding
of the OTf anions to the amine hydrogen atoms, are shown
in Figure 3. Selected bond distances and angles are listed in
Table 5. An abbreviated summary of crystal data and data
collection and processing is given in Table 1.
71.51(8)
the analogous Pt complex 6, the formation of an amido
complex in the reaction mixture is not detected. The 31P
NMR spectrum of isolated diamine complex 8 and the
reaction mixture are identical. The 1H NMR spectrum of the
diamine complex 8 shows the expected signals corresponding
to the bidentate phosphine ligand and the coordinated amine
with the NH2 signal appearing at 3.62 ppm in CD2Cl2.
(15) Other structurally characterized Pt(II) and Pd(II) amine phosphine
complexes: (a) Cooper, M. K.; Downes, J. M.; Goodwin, H. J.;
McPartlin, M. Inorg. Chim. Acta 1983, 76, L157. (b) Park, S.; Hedden,
D.; Rheingold, A. L.; Roundhill, D. M. Organometallics 1986, 5, 1305.
(c) Miyamoto, T. K.; Matsuura, Y.; Okude, K.; Ichida, H.; Sasaki, Y.
J. Organomet. Chem. 1989, 373, C8. (d) Matsuura, Y.; Okude, K.;
Ichida, H.; Miyamoto, T. K.; Sasaki, Y. Acta Crystallogr., Sect. C
1992, 48, 357. (e) Suzuki, T.; Morikawa, A.; Kashiwabara, K. Bull.
Chem. Soc. Jpn. 1996, 69, 2539. (f) Burrows, A. D.; Mingos, D. M.
P.; Lawrence, S. E.; White, A. J. P.; Williams, D. J. J. Chem. Soc.,
Dalton Trans. 1997, 1295. (g) van den Beuken, E. K.; Meetsma, A.;
Kooijman, H.; Spek, A. L.; Feringa, B. L. Inorg. Chim. Acta 1997,
264, 171. (h) You, D.; Kim, E.; Kang, S. O.; Ko, J.; Lee, S. H. Bull.
Korean Chem. Soc. 1998, 19, 565. (i) Habtemariam, A.; Watchman,
B.; Potter, B. S.; Palmer, R.; Parsons, S.; Parkin, A.; Sadler, P. J. J.
Chem. Soc., Dalton Trans. 2001, 1306.
Similarly, addition of excess 2,6-dimethylaniline to “L2-
Pd(NO3)2” yields the mononuclear diamine Pd complex
[PdL2(NH2-2,6-xylyl)2](NO3)2 (8) (eq 9, L2 ) dppma). Unlike
Inorganic Chemistry, Vol. 42, No. 4, 2003 1287

Anandhi et al.
Pt and Pd Imido Complexes. As anticipated, a series of
dinuclear diimido complexes is obtained by facile deproto-
nation of either the dimeric diamido complexes or the
monomeric diamine complexes. Salts from the base are found
to be associated with the imido complexes. The first of the
series, yellow (M ) Pt) or orange (M ) Pd) 9 crystallize
from a concentrated solution produced by adding excess LiN-
(SiMe3)2 to a DME suspension of the dppma Pt diamido
complexes 4 or the dppma Pd amine complex 7 (eq 10).
Spectroscopic and X-ray data indicate the isolation of a
dimeric imido complex incorporating 1 equiv of Li(DME)X
with the structure shown in eq 10.
Figure 4. ORTEP drawing (50% probability ellipsoids) of [{Pt(µ-N-4-
tol)(dppma)}2‚Li(DME)](BF4) (9) (M ) Pt; Ar ) 4-tol). Labeled and
unlabeled atoms are related by 2-fold axis bisecting the C2-C2 bond and
passing through the Li atom.
Table 6. Selected Distances (Å) and Angles (deg) for
[{Pt(µ-N-4-tol)(dppma)}2‚Li(DME)](BF4) (9) (M ) Pt; Ar ) 4-tol)
Pt1-N1
Pt1-N1
Pt1-P1
Pt1-P2
Pt1-Li1
2.061(6)
2.062(6)
2.235(2)
2.242(2)
2.827(17)
Pt1-Pt1
Li1-O1
Li1-N1
N1-C4
C2-C2
2.8519(6)
1.988(16)
2.032(16)
1.395(10)
1.49(2)
N1-Pt1-N1
N1-Pt1-P1
N1-Pt1-P1
N1-Pt1-P2
N1-Pt1-P2
73.7(3)
P1-Pt1-P2
C2-O1-C1
C2-O1-Li1
C1-O1-Li1
O1-Li1-O1
71.41(8)
112.9(9)
109.4(7)
124.2(8)
82.7(8)
178.34(18)
105.57(18)
109.49(18)
172.02(18)
in Figure 4. An abbreviated summary of crystal data and
data collection and processing is given in Table 2. Selected
bond distances and angles are listed in Table 6. The structure
reveals the expected interaction of the DME-coordinated Li
cation with the bridging imido group nitrogen atoms.
A similar reaction of the dppip Pt diamido dimers 4 or
the dppip Pd diamine complex 7 with LiN(SiMe3)2 in THF
or DME yields pale yellow Pt or red Pd imido complexes
10 (eq 11). As with the dppma imido complexes 9, a Li ion
is associated with 10; however, for 10 it is the ion pair LiN-
(SiMe3)2 and not Li(DME)+ that coordinates to the bridging
imido groups.
1H NMR spectra of both the Pt and Pd derivatives of 9 in
cold CD2Cl2 show signals for the chelated dppma ligands,
the Li-coordinate DME, and the imido tol groups. The tol
group ortho and meta protons appear as doublets indicating
either facile rotation about the N-C bond or rapid exchange
of the coordinated Li ion between the “top” and “bottom”
faces of the [L2Pt(µ-NAr)]2 unit. 31P NMR spectra of isolated
9 (M ) Pt) show singlets within a range of 28-29 ppm
flanked by 195Pt satellites. The P-Pt coupling constants are
reduced from those of the diamido complexes as expected
for a stronger donor imido ligand.14 Second-order coupling
(2JPt-P) of 81 Hz is observed in these complexes suggesting
the presence of a Pt-Pt bond14 and indicating integrity of
the dimeric unit in solution. 31P NMR spectra of 9 (M )
Pd) show sharp singlets in a range 50-52 ppm. The structure
of 9 (M ) Pt, X ) BF4) was determined by single-crystal
X-ray diffraction. A drawing of the cationic portion is shown
1288 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
Table 7. Selected Distances (Å) and Angles (deg) for [M(µ-N-4-tol)(dppip)]2‚LiN(SiMe3)2 (10) (M ) Pt, Pd; Ar ) 4-tol)
M ) Pt
M ) Pd
M ) Pt
M ) Pd
M1-M2
M1-P2
M1-P1
M2-P3
M2-P4
M1-N1
M1-N2
M2-N1
2.8615(3)
2.2506(12)
2.2516(12)
2.2487(13)
2.2670(12)
2.065(4)
2.7920(12)
2.288(2)
2.286(2)
2.285(2)
2.319(2)
2.069(5)
2.051(5)
2.061(6)
M2-N2
N1-C1N
N2-C8N
Li1-N1
Li1-N2
Li1-N3
M1-Li1
M2-Li1
2.062(4)
1.412(6)
1.411(6)
2.052(9)
2.050(9)
1.963(9)
2.827(7)
2.880(8)
2.076(5)
1.387(9)
1.411(8)
2.008(15)
2.011(14)
1.980(15)
2.794(13)
2.826(13)
2.059(3)
2.056(4)
P2-M1-P1
P3-M2-P4
N1-M1-N2
N1-M2-N2
M1-N1-M2
M1-N2-M2
C8N-N2-Li1
C1N-N1-M1
73.84(4)
73.48(5)
73.23(14)
73.37(15)
87.98(15)
87.95(14)
134.2(4)
128.6(3)
73.86(7)
73.19(7)
74.7(2)
74.4(2)
85.1(2)
85.16(18)
137.6(6)
128.7(4)
C1N-N1-M2
C8N-N2-M1
C8N-N2-M2
Li1-N1-M1
Li1-N1-M2
Li1-N2-M1
Li1-N2-M2
123.1(3)
124.7(3)
120.7(3)
86.7(3)
89.0(3)
86.9(3)
88.9(3)
122.9(4)
124.7(4)
119.3(4)
86.5(4)
88.0(4)
86.9(4)
87.5(4)
1H NMR spectra of 10 (M ) Pt, Pd) show the SiMe3 group
of the coordinated Li(NSiMe3)2 as a singlet at 0.05 ppm.
Consistent with the solid-state structure, the dppip methyl
groups are observed as two triplets indicating inequivalence
of the “top” and “bottom” methyl groups and suggesting that
dissociation of the coordinated Li(NSiMe3)2 and/or inversion
at the imido nitrogen center is slow on the NMR time
scale. As with the Li(DME)X adducts 9, the imido aryl
groups of 10 show equivalence of the ortho and meta protons.
In these complexes, the equivalence must come about by
free rotation about the C-N bond as other exchange
processes (e.g. dissociation of coordinated Li(NSiMe3)2)
would also exchange the dppip methyl groups. 31P NMR
spectra of 10 (M ) Pt) show singlets at -12.8 ppm with
satellites (1JPt-P ) 2758 Hz) and second-order P-Pt coupling
of 60 Hz for both Ph and 4-tol derivatives. The Pd imido
complex 10 (M ) Pd) shows a singlet at 8.9 ppm. The 1JPt-P
coupling constants in the Pt imido complexes are lower than
the starting diamido/amine complexes, consistent with the
stronger donor strength of imido over amine and amido
ligands.14
The molecular structures of both Pt and Pd diimido
complexes 10 (R ) 4-tol) were determined by single-crystal
X-ray diffraction. Crystals of the Pt and Pd derivatives are
isomorphous and isostructural. A drawing of the Pd structure,
essentially identical with that of the Pt derivative, is given
in Figure 5 and shows the interaction of the Li(NSiMe3)2
with the imido nitrogen atoms. An abbreviated summary of
crystal data and data collection and processing for both
structures is given in Table 2. Selected bond distances and
angles are listed in Table 7.
Figure 5. ORTEP drawing (50% probability ellipsoids) of [Pd(µ-N-4-
tol)(dppip)]2‚LiN(SiMe3)2 (10) (M ) Pd, Ar ) 4-tol).
Ion pair association is also observed when the dppma Pt
and Pd amine complexes 6 and 8, with nitrate counterions,are
deprotonated. Treatment of these complexes with excess LiN-
(SiMe3)2 gives the diimido complexes 11, which are associ-
ated with LiNO3 (eq 12). The 31P NMR spectra of these
complexes are similar to the dppma imido complexes 9.
However, no second-order P-Pt coupling is observed in the
Pt derivatives. This is consistent with the relatively long Pt-
Pt distance (3.1034(4) Å) observed in the X-ray crystal
structure. The 1H NMR spectrum of the Pt derivative shows
equivalent xylyl meta hydrogen atoms and ortho methyl
groups. In this case, the equivalence could be either from
free rotation about the N-C bond or from rapid exchange
of LiNO3 between the “top” and “bottom” face of [L2Pt(µ-
NAr)]2. The Pd derivative is very reactive with solvents, and
1H NMR data could not be obtained. Single-crystal X-ray
data for both the Pt and Pd derivatives show that their crystals
are isomorphous and that the complexes are isostructural. A
drawing of the Pd structure, essentially identical to that of
the Pt derivative, is given in Figure 6 and shows the
interaction of the LiNO3 with the imido nitrogen atoms. An
abbreviated summary of crystal data and data collection and
processing for both structures is given in Table 2. Selected
Spectroscopic data indicate that dppip Pt and Pd diimido
complexes are also isolated when NaN(SiMe3)2 is used as
the base but without NaN(SiMe3)2 coordination to the bridged
imido groups. (No SiMe3 signals are detected by 1H NMR.)
A signal at -79 or -156 ppm in the 19F NMR spectra
indicates the presence of NaOTf or NaBF4 in these imido
complexes probably bridging the imido nitrogen atoms
through the Na ion as observed for LiN(SiMe3)2 in 10 and
LiNO3 in 11 (see below).
Inorganic Chemistry, Vol. 42, No. 4, 2003 1289

Anandhi et al.
group. No NH or OH signals are observed. The dppip methyl
groups are inequivalent and are observed as two triplets
indicating a structure with a different “top” and “bottom”
face. The methyl groups of the imido 2,6-xylyl ligand
resonate as a broad singlet at 2.1 ppm, the two meta protons
resonate at 6.5 ppm as a broad doublet, and the para proton
resonates as a triplet at 6.2 ppm. The appearance of a broad
singlet for the xylyl methyl groups and the ortho and meta
hydrogen atoms suggests hindered rotation about the N-C
bond but less so than in the parent amido-hydroxo complex
5, which gives separate signals for each of the methyl groups
and hydrogen atoms. The presence of LiN(SiMe3)2 in the
isolated complex is indicated by the observation of the SiMe3
group as a singlet at 0.05 ppm. The 19F NMR spectrum shows
a peak at -154 ppm indicating the presence of the BF4 anion
and the incorporation of LiBF4.
Deprotonation of [L2Pt(µ-OH)2](BF4)2 (L2 ) dppip).
Addition of excess LiN(SiMe3)2 to dihydroxo dimer 1 in THF
forms the dioxo complex 13 where associated LiN(SiMe3)2
and LiBF4 units are probably coordinated to the oxo ligands
(eq 14). The reaction bears similarity to the above imido
preparations and to previous dioxo preparations for other
phosphine ligand complexes of Pt.5,6
Figure 6. ORTEP drawing (50% probability ellipsoids) of [Pd(µ-N-2,6-
xylyl)(dppma)]2‚LiNO3 (11) (M ) Pd). Labeled and unlabeled atoms are
related by a mirror plane containing the Pd and Li atoms.
bond distances and angles are listed in Table 8.
Deprotonation of [(L2Pt)2(µ-NHAr)(µ-OH)](BF4)2 (L2
) dppip). Addition of excess LiN(SiMe3)2 to a white
suspension of the amido-hydroxo complex 5 in THF forms
a pale yellow homogeneous solution containing the doubly
deprotonated oxo-imido complex 12, which is associated
(by NMR) with both LiBF4 and LiN(SiMe3)2 (eq 13).
The 31P NMR spectra of the isolated complex and the
reaction mixture show a broad peak with 195Pt satellites. The
coupling constant is 100 Hz lower than the hydroxo precursor
as anticipated for the stronger trans-donor oxo ligand. The
1H NMR spectrum of 13 shows only one dppip methyl group
triplet suggesting a more symmetric structure than that found
for the imido analogues 10 or rapid (on the NMR time scale)
dissociation of Li ions in solution. The SiMe3 group signal
is found at 0.05 ppm. Analytical data indicate the presence
of one LiN(SiMe3)2, but 1H NMR data on different samples
show this can vary between 1 and 2.
31P NMR spectra of the reaction mixtures when NaN-
(SiMe3)2 and KN(SiMe3)2 are used as deprotonating bases
show a singlet with satellites, shifted by ∼2 ppm relative to
that of 13. Pt-P coupling constants are 50 Hz smaller than
13 suggesting a stronger oxo donor. 1H NMR spectra of the
isolated solids show no signals for SiMe3 groups. However,
19F NMR spectra show signals at -156 ppm indicating the
31P NMR spectra of the reaction mixture and isolated 12
show a pair of doublets (JP-P ) 40 Hz) flanked by 195Pt
satellites with coupling constants lower than the starting
amido-hydroxo complex 5. The upfield doublet shows a
larger coupling constant than the downfield doublet similar
in magnitude to that observed for the Pt dioxo complex 13
(see below). In contrast to the diimido complexes 9 and 10
but in common with the dioxo complex 13 and the diimido
complex 11, second-order P-Pt coupling is not observed in
-
presence of BF4 and the likely presence of MBF4 (M )
Na, K). Although not fully characterized, these complexes
are probably analogues of 13 but with MBF4 association
instead of LiN(SiMe3)2. A stronger donor oxo ligand in these
complexes would be expected given the weaker M-oxo
interaction with the large Na+ and K+ ions as opposed to
the small, high charge density Li+ ions of 13.
1
the 31P NMR spectrum of 12. The H NMR spectrum of
isolated 12 shows signals for the dppip ligand and the imido
1290 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
Table 8. Selected Distances (Å) and Angles (deg) for [M(µ-N-2,6-xylyl)(dppma)]2‚LiNO3 (11) (M ) Pt, Pd)
M ) Pt
M ) Pd
M ) Pt
M ) Pd
M1-M2
M1-P1
M2-P2
M1-N3
M2-N3
Li1-M1
3.1034(4)
2.2521(13)
2.2511(14)
2.062(4)
2.055(4)
2.670(11)
3.0146(10)
2.2856(17)
2.2876(19)
2.053(5)
2.062(5)
2.651(18)
Li1-M2
Li1-O1
Li1-O2
Li1-N3
N3-C3
2.687(13)
2.023(14)
2.080(13)
2.080(10)
1.426(6)
2.652(16)
2.040(17)
2.060(18)
2.041(14)
1.401(8)
P1-M1-P1
P2-M2-P2
N3-M1-P1
N3-M2-P2
N3-M1-P1
N3-M2-P2
N3-M1-N3
71.04(6)
70.68(8)
70.90(9)
70.82(10)
170.60(14)
172.30(15)
105.54(14)
106.02(14)
76.6(3)
N3-M2-N3
C3-N3-M2
C3-N3-M1
M2-N3-M1
C3-N3-Li1
M2-N3-Li1
M1-N3-Li1
74.8(2)
119.9(3)
120.9(3)
97.83(16)
143.9(4)
81.1(3)
76.2(3)
118.8(4)
120.3(4)
94.2(2)
147.4(5)
80.6(4)
80.7(5)
172.64(11)
173.91(11)
106.75(11)
106.94(11)
74.5(2)
80.3(3)
Discussion
and oxo complexes by deprotonation, the precipitation of
Pd metal was observed on base addition. This is consistent
with the greater ease of reduction of Pd over Pt allowing
electron-transfer pathways to dominate. With the small bite
angle diphosphine ligands dppma and dppip, the reduction
pathway is suppressed allowing deprotonation to dominate.
As shown by Figures 2-4 and by the spectroscopic data,
the imido complexes are all found to be associated with Li
or Na ions. This is an indication of the basicity of the imido
ligands in these complexes and is consistent with the
expected lack of interaction of the imido nitrogen lone pair
with the metal centers. In addition, the geometry of the Pt2N2
unit ideally orients the lone pairs allowing the unit to act as
a chelating 4e- donor for the metal cations. Although we
do not believe these interaction are needed for the formation
of the complexes, they undoubtedly do add to their stability.
All of the imido complexes were prepared using similar
reaction conditions with a large excess of LiN(SiMe3)2. The
different Li salts, LiNO3, Li(DME)X, or LiN(SiMe3)2,
associated with the isolated complex appear to be the result
of solubility differences with the least soluble crystallizing
from the reaction mixture. This is suggested by the synthesis
of the LiNO3 adduct 11. If the deprotonation reaction is
conducted with a slight excess of LiN(SiMe3)2 the same
LiNO3 adduct 11 is isolated but it precipitates from the
reaction mixture as a microcrystalline solid. This solid
redissolves on addition of excess LiN(SiMe3)2, and the LiNO3
adduct may then be slowly precipitated as a crystalline solid
by cooling the solution. Similarly, the Li(DME)+ adduct 9
dissolves readily in DME only if LiN(SiMe3)2 is present and
reprecipitates as a crystalline solid on cooling the solution.
These observations suggest solution equilibria of the type
shown in eq 15, where the LiN(SiMe3)2 adduct is more
soluble than the LiNO3 adduct. Other possible equilibria are
evidenced by the isolation of the Li(DME)X adducts 9, where
solvent coordination to the Li ion has disrupted the ion paring
observed in 10 and 11. This undoubtedly happens in all of
As described in the Introduction, this work was initiated
to test the concept that small natural bite angle diphosphine
ligands favor the deprotonation of amido groups in the
dimeric Pt(II) complexes [L2Pt(NHAr)]2n+. This concept
originated from our previous observations on the L2 ) Ph2P-
(CH2)xPPh2 (x ) 1-4) ligand system, where only the n ) 1
(dppm) ligand complexes can be deprotonated6 but only after
the dppm methylene group is deprotonated (Scheme 1)
making an unambiguous conclusion on a bite angle effect
difficult. The ligands, dppip and dppma, used in the present
work do not contain an acidic hydrogen but have a similarly
small natural bite angle, and indeed the diamido and amine
complexes derived from them are readily deprotonated to
yield imido complexes. The origin of this enhanced acidity
for the small natural bite angle diphosphine complexes could
be either kinetic or thermodynamic. We have begun pKa
studies in a closely related amido-hydroxo system, and
initial results indicate that the thermodynamic acidity of the
dppip complex is actually slightly less than that of the
analogous dppe complex.16 Thus, in the current diamido
systems it is likely that the enhanced acidity is kinetic. That
is, the larger natural bite angle diphosphine complexes
studied earlier should deprotonate but the reaction is too slow
to be observed. The inhibition is probably steric in origin
where the phenyl groups of the diphosphine ligand prevent
approach of the base to the amido ligands. With the small
bite angle diphosphine ligands the phenyl groups are held
further away from the amido ligands allowing base access.
This suggests that diamido complexes prepared with larger
natural bite angle diphosphine ligands with the phenyl groups
replaced by smaller groups (e.g. Me, Et) will be readily
deprotonated.
A second aspect of the small bite angle of the diphosphine
ligands, important in our successful Pd diimido syntheses,
is their ability to stabilize Pt(II) and Pd(II) centers to
reduction as observed in decreases in reductive elimination
rates of Ni(II),17 Pd(II),18 and Pt(II)19 complexes with
decreasing diphosphine bite angle and in the reversibility of
dioxygen coordination to M0 (M ) Ni, Pd, Pt) complexes.20
In our previous attempts to prepare Pd analogues of Pt imido
(17) Kohara, T.; Yamamoto, T.; Yamamoto, A. J. Organomet. Chem. 1980,
192, 265.
(18) Marcone, J. E.; Moloy, K. G. J. Am. Chem. Soc. 1998, 120, 8527-
8528.
(19) Hofmann, P.; Heiss, H.; Neiteler, P.; Muller, G.; Lachmann, J. Angew.
Chem. 1990, 102 (8), 935-938; Angew. Chem., Intl. Ed. Engl. 1990,
29, 880.
(20) Yoshida, T.; Tatsumi, K.; Otsuka, S. Pure Appl. Chem. 1980, 52, 713-
(16) Anandhi, U.; Sharp, P. Work in progress.
727.
Inorganic Chemistry, Vol. 42, No. 4, 2003 1291

Anandhi et al.
the solutions with again the least soluble form being isolated
as the solid. Similar arguments can be applied to the oxo-
imido and the dioxo complexes. However, the much less
sterically demanding oxo ligand allows interaction of more
than a single salt.
Conclusions
The small natural bite angle diphosphines, Ph2PN(Me)-
PPh2 (dppma) and Ph2PC(Me2)PPh2 (dppip), enhance the
acidity of the Pt(II) and Pd(II) arylamine and arylamido
complexes [L2M(NH2Ar)]2+ and [{L2Pt(µ-NHAr)}2]2+ over
those of analogous larger natural bite angle diphosphine
complexes. The acidity enhancement is probably kinetic and
results from reduced steric crowding of the nitrogen centers
by the Ph2P units. This bite angle effect, along with a likely
reductive stabilization, has allowed the preparation of the
Pt and Pd imido complexes, [{L2M(µ-NAr)}2] (M ) Pt, Pd),
by deprotonation. The imido complexes are isolated, and
probably also exist in solution, as complexes with the Li,
Na, or K ion from the base LiN(SiMe3)2, NaN(SiMe3)2, or
KN(SiMe3)2 by coordination to the ion through the imido
nitrogen atoms.
Experimental Section
General Procedures. Experiments were performed under a
dinitrogen atmosphere in a Vacuum Atmospheres Corporation
drybox. Solvents were dried by standard techniques and stored under
dinitrogen over 4 Å molecular sieves or sodium metal. The ligands
dppip23 and dppma24 and the metal complexes L2PtCl2 and L2PdCl2
(L2 ) dppip,25 dppma26) were synthesized by literature procedures.
Silver salts and amines were purchased from commercial sources
and used as received. NMR spectra were recorded on a Bruker
AMX-250 spectrometer at 25 °C. Shifts are given in ppm with
positive values downfield of TMS (1H), external H3PO4 (31P), or
CFCl3 (19F). Desert Analytics or Atlantic Micro Lab or National
Chemical Consulting performed the microanalyses (inert atmo-
sphere). The presence of CH2Cl2 of crystallization in the analyzed
The structures of 9-11 confirm their identity as dimeric
bridging imido complexes with Li ion bonding to the imido
group nitrogen atoms. Also confirmed is the short Pt-Pt
distance in complexes 9 (2.8519(6) Å) and 10 (2.8615(3)
Å) indicated by the observation of second-order P-Pt
coupling in these two complexes. The longer distance in 11
(3.1034(3) Å) is also indicated by the absence of second-
order P-Pt coupling. The short distance in 9 and 10 is
achieved by folding of the structures at the common N-N
edge of the two square planar metal centers (9, 58°; 10, 57°
(Pt), 59° (Pd)). The longer M-M distance of 11 results from
a smaller fold angle (Pt, 28°; Pd, 32°) that keeps the two
metal centers apart. The small fold angle of 11 may be
attributed to steric effects of the xylyl methyl groups. The
observed second-order P-Pt coupling in the Pt derivatives
of 9 and 10 also indicates that the dimeric structures are
retained in solution. Thus, there is no indication of the
monomeric form L2PtdNAr recently reported for the Ni
imido complex L2NidNAr.21
A shortening of the M-N distances in the imido com-
plexes from those of the precursor amido and amine
complexes is expected given the greater donor strength of
the imido ligand. The average M-N bond distances for the
imido complexes are 2.062(1), 2.060(4), and 2.058(5) Å for
Pt and 2.06(6) and 2.058(6) Å for Pd with all falling in a
tight range around 2.06 Å. This is clearly shorter than the
Pd amine complexes 7, which have an average Pd-N
distance of 2.15(1) Å. While there are no structures for amido
complexes with dppma and dppip ligands, those reported in
the literature with other phosphine ligands trans to bridging
amido groups have average Pt-N or Pd-N distances that
range from 2.082(4) to 2.15(3)6,9m,22 again demonstrating
shorter distances for the imido complexes reported here.
1
samples was confirmed by H NMR spectroscopy in CDCl3.
Platinum Complexes. [L2Pt(µ-OH)]2(BF4)2 (1) (L2 ) dppip,
dppma). To a stirred CH2Cl2 (10 mL) suspension of L2PtCl2 (0.226
mmol) is added solid AgBF4 (0.092 g, 0.47 mmol) in portions. The
mixture is stirred for 1 h in the dark, after which time the AgCl
precipitate is filtered off with the aid of diatomaceous earth. The
clear filtrate is concentrated under reduced pressure, and the white
product is precipitated with diethyl ether. Yield: 68-70% (∼100
mg). Samples for analysis were obtained by recrystallization from
CH2Cl2/Et2O. dppip: 31P{1H} NMR (CH2Cl2) -30.5 (s with
satellites, JPt-P ) 3125 Hz); 1H NMR (CD2Cl2) 8.24-7.55 (m, 40H,
Ph), 2.02 (br s, OH), 1.37 (t, 3JP-H ) 15.0 Hz, 12H, CMe2). Anal.
Calcd (found) for C54H54B2F8O2P4Pt2‚0.5CH2Cl2: C, 44.65 (44.96);
H, 3.79 (3.97). dppma: 31P{1H} NMR (CH2Cl2) 10.5 (s with
(22) (a) O’Mahoney, C. A.; Parkin, I. P.; Williams, D. J.; Woollins, J. D.
Polyhedron 1989, 8, 1979-1981. (b) Park, S.; Rheingold, A. L.;
Roundhill, D. M. Organometallics 1991, 10, 615-623. (c) Alcock,
N. W.; Bergamini, P.; Kemp, T. J.; Pringle, P. G.; Sostero, S.; Traverso,
O. Inorg. Chem. 1991, 30, 1594-1598. (d) Villanueva, L. A.; Abboud,
K. A.; Boncella, J. M. Organometallics 1994, 13, 3921-3931. (e)
Xu, X.; James, S. L.; Mingos, D. M. P.; White, A. J. P.; Williams, D.
J. J. Chem. Soc., Dalton Trans. 2000, 3783-3790. (f) Xia, A.; Sharp,
P. Inorg. Chem. 2001, 40, 4016-4021.
(23) Hewertson, W.; Watson, N. R. J. Chem. Soc. 1962, 1490-93.
(24) (a) Ewart, G.; Lane, A. P.; McKechnie, J.; Payne, D. S. J. Chem. Soc.
1964, 1543-1547. (b) Wang, F. T.; Najdzionek, J.; Leneker, K. L.;
Wasserman, H. B. D. M. Synth. React. Inorg. Metal-Org. Chem. 1978,
8, 119. (c) Sekabunga, E. J.; Smith, M. L.; Webb, T. R.; Hill, W. E.
Inorg. Chem. 2002, 41, 1205-1214.
(25) Barkley, J.; Ellis, M.; Higgins, S. J.; McCart, M. K. Organometallics
1998, 17, 1725-1729.
(26) Browning, C. S.; Farrar, D. H. J. Chem. Soc., Dalton Trans. 1995,
521-530.
(21) Mindiola, D. J.; Hillhouse, G. L. J. Am. Chem. Soc. 2001, 123, 4623-
4624.
1292 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
satellites, JPt-P ) 3483 Hz); 1H NMR (CD2Cl2) 7.73-7.58 (m, 40H,
Ph), 3.02 (br s, OH) 2.50 (t, 3JP-H ) 12.5 Hz, 6H, N-Me). Within
minutes of dissolution, the 1H and 31P NMR spectra of the dppma
complex indicate the presence of a small quantity of an unidentified
complex (31P peak at 9.3). However, the purity of the isolated
product is confirmed by elemental analysis. Anal. Calcd (found)
for C50H48B2F8N2O2P4Pt2: C, 42.97 (42.62); H, 3.47 (3.56); N, 2.01
(2.01).
[(dppip)2Pt2(µ-NH-2,6-xylyl)(µ-OH)](BF4)2 (5). To a stirred
solution of [Pt(µ-OH)(dppip)]2(BF4)2‚0.5CH2Cl2 (0.100 g, 0.0683
mmol) in 5 mL of CH2Cl2 is added 2,6-dimethylaniline (0.037 g,
0.30 mmol). The homogeneous solution is stirred overnight,
concentrated under reduced pressure, and layered with diethyl ether
to obtain the white crystalline product. Yield: 0.070 g (64%). 31P-
{1H} NMR (CH2Cl2): -29.6 (d, 1JPt-P ) 3248 Hz, 2JP-P ) 60 Hz),
1
2
1
-22.8 (d, JPt-P ) 2771 Hz, JP-P ) 60 Hz). H NMR (CD2Cl2):
8.31-6.58 (m, 40H, Ph), 6.02 (d, 3JH-H ) 7.5 Hz, 1H, xylyl), 5.95
(t, 3JH-H ) 7.5 Hz, 1H, xylyl), 5.59 (d, 3JH-H ) 7.5 Hz, 1H, xylyl),
4.61 (br, s, NH), 3.32 (s, 3H, xylyl-CH3), 2.34 (br s, OH), 1.64 (s,
3H, xylyl-CH3), 1.37 (t, 3JP-H ) 15.0 Hz, 6H, CMe2), 0.76 (t, 3JP-H
) 15.0 Hz, 6H, CMe2). Anal. Calcd (found) for C62H63B2F8NOP4-
Pt2‚CH2Cl2: C, 46.98 (46.94); H, 4.07 (4.41); N, 0.87 (1.30).
[(dppma)Pt(NH2-2,6-xylyl)2](NO3)2 (6). To a stirred suspension
of [Pt(NO3)2(dppma)] (0.100 g, 0.139 mmol) in 3 mL of CH2Cl2 is
added 2,6-dimethylaniline (0.075 g, 0.62 mmol) in 2 mL of CH2-
Cl2. The homogeneous solution is stirred overnight and layered with
an equal amount of toluene to obtain the pure white solid product.
Yield: 0.090 g (67%). 31P{1H} NMR (CH2Cl2): 3.0 (br, s with
satellites, JPt-P ) 3810 Hz). (The 31P{1H} NMR spectrum of the
reaction mixture shows a broad signal at 13.6 ppm (JPt-P ) 3222
[Pt(NO3)2(dppma)] (2). To a stirred suspension of (dppma)-
PtCl2 (0.100 g, 0.150 mmol) in 10 mL of CH2Cl2 is added solid
AgNO3 (0.150 g, 0.883 mmol) in portions. The mixture is stirred
for 3 h. The AgCl precipitate and excess AgNO3 are then removed
by filtration through a pad of diatomaceous earth. The resulting
clear filtrate is concentrated under reduced pressure, and the
analytically pure white product is precipitated with diethyl ether
or THF. Yield: 0.092 g (85%). 31P{1H} NMR (CH2Cl2): 2.6 (s
1
with satellites, JPt-P ) 3771 Hz). H NMR (CD2Cl2): 7.75-7.48
(m, 20H, Ph), 2.23 (t, 3JP-H ) 12.5 Hz, 3H, N-Me). Anal. Calcd
(found) for C25H23N3O6P2Pt: C, 41.79 (42.20); H, 3.23 (3.29); N,
5.85 (5.85).
[(dppip)Pt(µ-NHPh)]2(BF4)2 (4) (L2 ) dppip; Ar ) Ph). To a
stirred suspension of [Pt(µ-OH)(dppip)]2(BF4)2‚0.5CH2Cl2 (0.100
g, 0.0683 mmol) in 5 mL of CH2Cl2 is added aniline (0.035 g,
0.38 mmol) in 2 mL of CH2Cl2. The resulting homogeneous solution
is stirred for 5 h. The solution is then concentrated and the white
solid product precipitated by layering the solution with diethyl ether.
Yield: 0.095 g (88%). 31P{1H} NMR (CH2Cl2): -21.9 (s with
1
3
Hz)). H NMR (CDCl3): 7.78-7.56 (m, 20H, Ph), 6.89 (d, JH-H
3
) 7.50 Hz, 4H, xylyl), 6.59 (t, JH-H ) 7.5 Hz, 2H, xylyl), 4.62
(s, br, NH2), 2.34 (t, JP-H ) 12.5 Hz, 3H, N-Me), 2.16 (s, 12H,
3
xylyl-CH3). Anal. Calcd (found) for C41H45N5O6P2Pt: C, 51.24
(51.20); H, 4.72 (4.69); N, 7.29 (7.19).
1
[{Pt(µ-N-4-tol)(dppma)}2‚Li(DME)](BF4) (9). LiN(SiMe3)2
(0.050 g, 0.30 mmol) in 5 mL of DME is added dropwise to a
stirred suspension of [Pt(µ-NH-4-tol)(dppma)]2(BF4)2 (0.100 g,
0.0635 mmol) in 10 mL of DME. The suspension of the diamido
complex initially turns yellow but becomes an orange solution after
complete addition. The orange solution is stirred for 1 h, concen-
trated, and then stored at -30 °C to obtain the yellow crystalline
product. Crystals for the X-ray analysis were obtained by dissolving
the product in a DME solution of LiN(SiMe3)2 and cooling the
mixture to -30 °C. Yield: 0.070 g (70%). 31P{1H} NMR (DME):
28.9 (s with satellites, 1JPt-P ) 2792 Hz, 2JPt-P ) 81 Hz). 1H NMR
satellites, JPt-P ) 2843 Hz). H NMR (CD2Cl2): 7.84-7.48 (m,
40H, Ph), 6.3 (v br s, 4H, NPh), 5.98-5.88 (m, 6H, NPh), 4.41 (br
1
3
t, JN-H ) 5 Hz, 2H, NH), 1.12 (t, JP-H ) 15.0 Hz, 6H, CMe2),
3
0.93 (t, JP-H ) 15.0 Hz, 6H, CMe2). Anal. Calcd (found) for
C66H64B2F8N2P4Pt2: C, 50.37 (49.98); H, 4.10 (4.27); N, 1.78
(2.02).
[L2Pt(µ-NH-4-tol)]2(BF4)2 (4) (L2 ) dppip, dppma; Ar ) Ph).
To a stirred suspension of [L2Pt(µ-OH)]2(BF4)2 (0.100 g, ∼0.07
mmol) in 5 mL of CH2Cl2 is added 4-toluidine (0.035 g, 0.33 mmol)
in 2 mL of CH2Cl2. The resulting homogeneous solution is stirred
for 5 h (dppma) or heated at 50 °C for 1 h (dppip). The solution is
then concentrated and the white solid product precipitated with
diethyl ether. The dppip product precipitates with toluidine, which
can be removed by recrystallization from CH2Cl2/Et2O. Yield: 80-
85% (∼0.09 g). dppip: 31P{1H} NMR (CH2Cl2) -22.0 (s with
3
(CD2Cl2, 0 °C): 7.67-7.08 (m, 40H, Ph), 6.27 (d, JH-H ) 7.5
Hz, 4H, tol), 6.00 (d, 3JH-H ) 7.5 Hz, 4H, tol), 3.52 (s, 4H, DME),
3
3.01(s, 6H, DME), 2.17 (t, JP-H ) 12.5 Hz, 6H, NMe), 2.07 (s,
6H, tol).
1
[Pt(µ-NPh)(dppip)]2‚LiN(SiMe3)2 (10) (M ) Pt, Ar ) Ph).
LiN(SiMe3)2 (0.050 g, 0.30 mmol) in 5 mL of THF is added
dropwise to a stirred suspension of [Pt(µ-NHPh)(dppip)]2(BF4)2
(0.100 g, 0.0636 mmol) in 10 mL of THF. On addition of the base,
the colorless suspension slowly turns yellow, and after complete
addition, a clear yellow solution is obtained. The yellow solution
is stirred for an additional 1 h, concentrated under reduced pressure,
layered with an equal volume of petroleum ether, and cooled to
-30 °C to obtain yellow prismatic crystals. Yield: 0.070 g (71%).
satellites, JPt-P ) 2841 Hz); H NMR (CD2Cl2, 250 MHz, 27 °C)
7.83-7.43 (m, 40H, Ph), 6.20 (br s, 4H, tol), 5.66 (d, 3JH-H ) 8.0
Hz, 4H, tol), 4.43 (br t, 1JN-H ) 5 Hz, 2H, NH), 1.71 (s, 6H, tol),
0.99 (t, 3JP-H ) 15.0 Hz, 12H, CMe2); 1H NMR (CD2Cl2, 300 MHz,
-70 °C) 7.64-7.33 (m, 40H, Ph), 6.36 (d, 3JH-H ) 5 Hz, 2H, tol),
3
3
5.76 (d, JH-H ) 5 Hz, 2H, tol), 5.67 (d, JH-H ) 5 Hz, 2H, tol),
3
5.36 (d, JH-H ) 5 Hz, 2H, tol), 4.45 (br s, 2H, NH), 1.66 (s, 6H,
3
3
tol), 0.95 (t, JP-H ) 15 Hz, 6H, CMe2), 0.89 (t, JP-H ) 15 Hz,
6H, CMe2). Anal. Calcd (found) for C68H68B2F8N2P4Pt2: C, 51.02
(51.07); H, 4.28 (4.19); N, 1.75 (2.13). dppma: 31P{1H} NMR (CH2-
1
31P{1H} NMR (THF): -12.8 (s with satellites, JPt-P ) 2753 Hz,
1
2JPt-P ) 60 Hz). H NMR (CD2Cl2): 7.85-7.15 (m, 40H, Ph),
1
Cl2) 19.6 (s with satellites, JPt-P ) 2979 Hz); H NMR (CD2Cl2,
3
3
250 MHz, 27 °C) 7.75-7.19 (m, 40H, Ph), 6.37 (br d, 3JH-H ) 7.5
6.43 (d, JH-H ) 7.5 Hz, 4H, NPh), 5.79 (t, JH-H ) 7.5 Hz, 4H,
3
3
1
NPh), 5.32 (t, JH-H ) 7.5 Hz, 2H, NPh), 0.95 (t, JP-H ) 15.0
Hz, 6H, CMe2), 0.73 (t, 3JP-H ) 15.0 Hz, 6H, CMe2), 0.06 (s, 18H,
N(SiMe3)2).
Hz, 4H, tol), 5.81 (br s, 4H, tol), 4.64 (br t, JN-H ) 5 Hz, 2H,
NH), 2.13 (t, JP-H ) 10.0 Hz, 6H, NMe), 2.04 (s, 6H, tol). H
NMR (CD2Cl2, 250 MHz, -75 °C) 7.72-7.23 (m, 40H, Ph), 6.54
3
1
3
3
(d, JH-H ) 7.5 Hz, 2H, tol), 6.34 (d, JH-H ) 7.5 Hz, 2H, tol),
[Pt(µ-N-4-tol)(dppip)]2‚LiN(SiMe3)2 (10) (M ) Pt, Ar ) 4-tol).
The procedure is the same as for the Ph derivative. Yield: 0.080
(81%) of yellow prismatic crystals. Crystals for the X-ray analysis
were obtained as described for the Ph derivative. 31P{1H} NMR
(THF): -12.8 (s with satellites, 1JPt-P ) 2758 Hz, 2JPt-P ) 60 Hz).
1H NMR (CD2Cl2): 7.85-7.16 (m, 40H, Ph), 6.27 (d, 3JH-H ) 7.5
3
3
6.24 (d, JH-H ) 7.5 Hz, 2H, tol), 5.38 (d, JH-H ) 7.5 Hz, 2H,
3
tol), 4.53 (br s, 2H, NH), 2.09 (t, JP-H ) 10.0 Hz, 6H, NMe),
1.99 (s, 6H, tol); IR (thin film) 3250 cm-1 (N-H). Anal. Calcd
(found) for C64H62B2F8N4P4Pt2‚1.5CH2Cl2: C, 46.22 (46.28); H,
3.85 (3.89); N, 3.29 (3.25).
Inorganic Chemistry, Vol. 42, No. 4, 2003 1293

Anandhi et al.
3
Hz, 4H, tol), 5.56 (d, 3JH-H ) 7.50 Hz, 4H, tol), 1.82 (s, 6H, tol),
(br t, 12H, JP-H ) 15 Hz, CMe2), 0.02 (br s, 36H, N(SiMe3)2).
Anal. Calcd (found) for C54H52O2P4Pt2‚LiNSi2C6H18‚2LiBF4: C,
44.99 (44.99); H, 4.40 (4.12); N, 0.87 (0.68).
3
3
0.95 (t, JP-H ) 15.0 Hz, 6H, CMe2), 0.86 (t, JP-H ) 15.0 Hz,
6H, CMe2), 0.02 (s, 18H, N(SiMe3)2). Anal. Calcd (found) for
C74H84LiN3P4Pt2Si2: C, 55.81 (54.29, 52.05); H, 5.32 (5.75, 5.21);
N, 2.64 (2.38, 2.15). The low analysis results suggest entrainment
of LiBF4 in the bulk samples or partial hydrolysis of these very air
sensitive samples.
[Pt(µ-N-2,6-xylyl)(dppma)]2‚LiNO3 (11) (M ) Pt). LiN-
(SiMe3)2 (0.064 g, 0.38 mmol) in 5 mL of DME is added dropwise
to a stirred suspension of [Pt(NH2-2,6-xylyl)(dppma)](NO3)2 (0.100
g, 0.104 mmol) in 10 mL of DME. The suspension of the diamido
complex initially turns yellow but becomes an orange solution after
the addition is complete. The orange solution is stirred for 1 h and
then stored at -30 °C to obtain the orange crystalline product.
Crystals for the X-ray analysis were obtained from THF as described
for 10. Yield: 0.040 g (51%). 31P{1H} NMR (DME): 28.0 (s with
[Pt(µ-O)(dppip)]2‚nMBF4 (M ) Na or K). MN(SiMe3)2 (0.055
g, M ) Na; 0.60 g, M ) K, 0.30 mmol) in 5 mL of THF is added
dropwise to a stirred suspension of [Pt(µ-OH)(dppip)]2(BF4)2 (0.100
g, 0.0703 mmol) in 10 mL of THF. The resulting pale yellow
solution is allowed to stir for an additional 20 min. Layering the
solution with petroleum ether and storing at -30 °C yields the pale
yellow solid product. Yield (assuming n ) 1): M ) Na, 0.055 g
(58%, assuming n ) 1); M ) K, 0.050 g (52%, assuming n ) 1).
Spectroscopic data are the same for both derivatives. 31P{1H} NMR
(THF): -24.2 (s with satellites, 1JPt-P ) 2950 Hz). 1H NMR (CD2-
3
Cl2): 8.24-7.55 (m, 40H, Ph), 1.30 (t, 12H, JP-H ) 15.0 Hz,
CMe2). 19F NMR (THF): -156.2 (s).
Palladium Complexes. Reaction of PdCl2(dppma) with Ag-
NO3. To a stirred suspension of PdCl2(dppma) (0.100 g, 0.173
mmol) in 8 mL of CH2Cl2 is added solid AgNO3 (0.060 g, 0.35
mmol) in portions. The mixture is stirred for 3 h. The AgCl
precipitate is removed by filtration through diatomaceous earth. The
resulting clear filtrate is concentrated under reduced pressure, and
a lemon-yellow solid is precipitated with diethyl ether (0.070 g).
31P NMR spectroscopy of the reaction mixtures and the dissolved
isolated solid indicates the presence of a mixture of compounds.
1
1
satellites, JPt-P ) 2729 Hz). H NMR (CD2Cl2, -20 °C): 7.78-
3
7.56 (m, 40H, Ph), 6.89 (d, JH-H ) 7.5 Hz, 4H, xylyl), 6.59 (t,
3JH-H ) 7.50 Hz, 2H, xylyl), 3.52 (s, 4H, DME), 3.01 (s, 6H,
3
DME), 2.17 (t, JP-H ) 12.5 Hz, 6H, NMe), 2.07 (s, 12H, xylyl-
CH3). Anal. Calcd (found) for C66H64N4P4Pt2‚2LiNO3‚C4H10O2: C,
50.79 (50.68); H, 4.51 (4.72); N, 5.08 (4.44).
[Pt2(µ-N-2,6-xylyl)(µ-O)(dppip)2]‚LiN(SiMe3)2‚LiBF4 (12). LiN-
(SiMe3)2 (0.050 g, 0.30 mmol) in 4 mL of THF is added dropwise
to a stirred suspension of [Pt2(µ-NH-2,6-xylyl)(µ-OH)(dppip)2]-
(BF4)2 (0.160 g, 0.105 mmol) in 10 mL of THF. On addition of
the base, the colorless suspension slowly becomes yellow, and after
complete addition, a clear yellow solution forms. The yellow
solution is stirred for an additional 1 h and then concentrated under
reduced pressure, layered with equal amount of petroleum ether,
and cooled to -30 °C to obtain the yellow crystalline product.
Yield: 0.100 g (59%). 31P{1H} NMR (THF): -12.3 (d with
satellites, 1JPt-P ) 3039 Hz, 2JP-P ) 41 Hz, P trans to oxo), -22.8
31P{1H} NMR (CH2Cl2): 32.7 (d, JP-P ) 21 Hz), 26.5 (d, JP-P
2
2
) 21 Hz), 29.1 (s). 1H NMR (CD2Cl2): 7.79-7.61 (m, 20H, Ph),
3
2.56 (t, JP-H ) 12.5 Hz, 3H, N-Me).
Reaction of PdCl2(dppma) with AgX (X ) BF4, OTf). To a
stirred CH2Cl2 (8 mL) suspension of PdCl2(dppma) (0.100 g, 0.174
mmol) containing one drop of water is added AgX (0.365 mmol)
in solid portions. After complete addition, the reaction mixture is
stirred for 1 h in the dark and the AgCl precipitate is removed by
filtration through diatomaceous earth. The resulting clear orange
solution is concentrated under reduced pressure and the yellow
product precipitated with diethyl ether. Yield for X ) BF4: 0.060
g. Crystals of Pd(OTf)2(dppma) for the X-ray analysis were obtained
by layering the concentrated mixture with diethyl ether. 31P{1H}
NMR (CH2Cl2): 26.1 (s). 1H NMR (CD2Cl2): 7.85-7.35 (m, 40H,
Ph), 4.34 (br s, OH), 2.70 (t, 3JP-H ) 12.50 Hz, 6H, N-Me). Anal.
Found: C, 4.18; H, 3.41; N, 2.06. X ) OTf: yield 0.070 g; 31P-
1
2
(d with satellites, JPt-P ) 2571 Hz, JP-P ) 41 Hz, P trans to
1
imido). H NMR (CD2Cl2): 8.59-7.14 (m, 40H, Ph), 6.28 (br d,
3JP-H ) 7.5 Hz, 2H, xylyl) 6.02 (br t, 3JP-H ) 7.5 Hz, 1H, xylyl),
3
2.1(br, s, 6H, xylyl), 1.18 (t, JP-H ) 15.0 Hz, 12H, CMe2), 0.05
(s, 18H, N(SiMe3)2). 19F{1H} NMR (THF): -154.1 (s, BF4). Anal.
Calcd (found) for C68H79BF4N2OSi2Li2P4Pt2: C, 50.67 (50.18); H,
4.94 (4.77); N, 1.74 (1.76).
{1H} NMR (CH2Cl2) 26.5 (s); H NMR (CD2Cl2) 7.82-7.62 (m,
40H, Ph), 2.66 (t, JP-H ) 12.50 Hz, 6H, N-Me). Anal. Found:
1
[Pt(µ-N-4-tol)(dppip)]2‚nNaBF4. NaN(SiMe3)2 (0.055 g, 0.30
mmol) in 5 mL of THF is added dropwise to a stirred suspension
of [Pt(µ-NH-4-tol)(dppip)]2(BF4)2 (0.100 g, 0.0625 mmol) in 10
mL of THF. The colorless suspension, on addition of the base,
slowly turns yellow, and after complete addition, a clear yellow
solution is obtained. The yellow solution is stirred for an additional
1 h, concentrated under reduced pressure, layered with an equal
volume of petroleum ether, and cooled to -30 °C to obtain the
3
C, 44.04; H, 3.53; N, 2.08.
Pd(OTf)2(dppip) (3). To a stirred CH2Cl2 (8 mL) suspension
of PdCl2(dppip) (0.100 g, 0.170 mmol) is added AgOTf (0.090 g,
0.35 mmol) in solid portions. After the addition of AgOTf, the
reaction mixture is stirred for 1 h in the dark and the AgCl
precipitate is removed by filtration through diatomaceous earth. The
resulting clear green solution is concentrated under reduced pressure,
and the pale yellow solid product is precipitated with diethyl ether.
Yield: 0.110 g (79%). 31P{1H} NMR (CH2Cl2): -16.5 (s). 1H NMR
orange-yellow crystalline product. Yield: 0.065 g (68%, assuming
1
n ) 1). 31P{1H} NMR (THF): -13.2 (s with satellites, JPt-P
)
2707 Hz). 1H NMR (CD2Cl2, 0 °C): 7.85-7.17 (m, 40H, Ph), 6.27
(d, JP-H ) 7.5 Hz, 4H, tol), 5.56 (d, JP-H ) 7.5 Hz, 4H, tol),
1.82 (s, 6H, tol), 0.95 (t, JP-H ) 15.0 Hz, 6H, CMe2), 0.86 (t,
3
3
3
(CD2Cl2): 8.08-7.57(m, 20H, Ph), 1.37 (t, JP-H ) 15.0 Hz, 6H,
CMe2). Anal. Calcd (found) for C29H26F6O6P2PdS2: C, 42.63
3
3JP-H ) 15.0 Hz, 6H, CMe2). 19F NMR (THF): -156.2 (s).
[Pt(µ-oxo)(dppip)]2‚LiN(SiMe3)2‚2LiBF4 (13). LiN(SiMe3)2
(0.050 g, 0.30 mmol) in 5 mL of THF is added dropwise to a stirred
suspension of [Pt(µ-OH)(dppip)]2(BF4)2 (0.100 g, 0.064 mmol) in
10 mL of THF. The resulting pale yellow solution is allowed to
stir for an additional 20 min and then concentrated in vacuo.
Layering the concentrated solution with petroleum ether and storing
at -30 °C yields the pale yellow solid product. Yield: 0.060 g
(42.36); H, 3.20 (3.06).
[Pd(NH2-4-tol)2(dppip)](OTf)2 (7) (L2 ) dppip, X ) OTf).
To a stirred suspension of Pd(OTf)2(dppip) (0.100 g, 0.123 mmol)
in 8 mL of CH2Cl2 is added 4-toluidine (0.035 g, 0.33 mmol) in 2
mL of CH2Cl2. The resulting homogeneous yellow solution is stirred
for 2 h, after which time the solution is concentrated and the yellow
product precipitated with diethyl ether. Yield: 0.100 g (80%).
Crystals for the X-ray analysis were obtained by layering a
concentrated CH2Cl2 solution with diethyl ether. 31P{1H} NMR
(CH2Cl2): -13.1 (s). 1H NMR (CDCl3): 8.01-7.54 (m, 20H, Ph),
(59%). 31P{1H} NMR (THF): -23.2 (br s with satellites, 1JPt-P
)
1
3008 Hz). H NMR (CD2Cl2): 8.24-7.55 (br m, 40H, Ph), 1.07
1294 Inorganic Chemistry, Vol. 42, No. 4, 2003

Platinum and Palladium Imido and Oxo Complexes
3
3
6.82 (d, JH-H ) 7.5 Hz, 4H, tol), 6.25 (d, JH-H ) 7.5 Hz, 4H,
(0.100 g, 0.0971 mmol) in 5 mL of THF was added dropwise LiN-
(SiMe3)2 (0.045 g, 0.27 mmol) in 2 mL of THF. The yellow
suspension of amine complex on addition of the base slowly
changed in to red and after the complete addition turned in to a
clear deep red solution. The red solution was stirred for additional
1 h for the completion of deprotonation, concentrated under reduced
pressure, layered with an equal amount of petroleum ether, and
cooled to -30 °C to obtain red prismatic crystals. Crystals for the
X-ray analysis were obtained in this way. Yield: 0.045 g, 65%.
3
tol), 5.85 (br s, 4H, NH2), 1.98 (s, 6H, tol), 1.08 (t, JP-H ) 15.0
Hz, 6H, CMe2). Anal. Calcd (found) for C43H44F6N2O6P2PdS2‚CH2-
Cl2: C, 47.34 (47.19); H, 4.15 (4.23), N, 2.51 (2.56).
[Pd(NH2-4-tol)2(dppma)](X)2 (7) (L2 ) dppma, X ) BF4,
OTf). To a stirred suspension of (dppma)PdCl2 (0.100 g, 0.174
mmol) in 10 mL of CH2Cl2 is added AgX (X ) BF4, 0.071 g; X
) OTf, 0.094 g; 0.36 mmol). The mixture is stirred for 2 h. The
AgCl precipitate is removed by filtration through diatomaceous
earth. The resulting clear filtrate is concentrated under reduced
pressure to 3 mL, and to this clear solution is added 4-toluidine
(0.040 g, 0.37 mmol) in 2 mL of CH2Cl2. The homogeneous
solution is stirred for 3 h and layered with an equal amount of
Et2O to obtain the yellow solid product. Crystallization from CH2-
Cl2/Et2O gives analytically pure products. Crystals for the X-ray
analysis were obtained by layering a concentrated CH2Cl2 solution
with toluene. X ) BF4: yield 0.090 g (58%); 31P{1H} NMR (CH2-
Cl2) 32.0 (s); 1H NMR (CDCl3) 7.73-7.41 (m, 20H, Ph), 6.90 (d,
1
31P{1H} NMR (THF): 8.6 (s). H NMR (CD2Cl2, 0 °C): 7.76-
7.14 (m, 40H, Ph), 6.53 (d, 3JH-H ) 7.5 Hz, 4H, tol), 5.60 (d, 3JH-H
3
) 7.5 Hz, 4H, tol), 1.82 (s, 6H, tol), 0.89 (t, JP-H ) 15 Hz, 6H,
3
CMe2), 1.18 (t, JP-H ) 15 Hz, 6H, CMe2), 0.05 (s, 18H,
N(SiMe3)2).
[Pd(µ-N-4-tol)(dppip)]2‚xNaOTf. NaN(SiMe3)2 (0.050 g, 0.27
mmol) in 2 mL of THF was added dropwise to a stirred suspension
of [Pd(NH2-4-tol)2(dppip)](OTf)2 (0.100 g, 0.0971 mmol) in 5 mL
of THF. The yellow suspension of amine complex on addition of
the base slowly changed in to red and after the complete addition
turned in to a clear deep red solution. The red solution was stirred
for additional 1 h for the completion of deprotonation, concentrated
under reduced pressure, layered with an equal amount of petroleum
ether, and cooled to -30 °C to obtain the red crystalline product.
Yield: 0.045 g, 65%. 31P{1H} NMR (THF): 9.2 (s). 1H NMR (CD2-
Cl2, 0 °C): 7.76-7.14 (m, 40H, Ph), 6.53 (d,3JH-H ) 7.5 Hz, 4H,
3JH-H ) 7.5 Hz, 4H, tol), 6.52 (d, JH-H ) 7.5 Hz, 4H, tol), 5.85
3
(br s, 4H, NH2), 2.23 (t, 3JP-H ) 12.5 Hz, 3H, NMe), 2.15 (s, 6H,
tol). Anal. Calcd (found) for C39H41B2F8N3P2Pd: C, 52.34 (51.95);
H, 4.62 (4.61); N, 4.70 (4.52). X ) OTf: yield 0.095 g (54%);
31P{1H} NMR (CH2Cl2) 32.4 (s); 1H NMR (CDCl3) 7.74-7.48 (m,
3
3
20H, Ph), 6.89 (d, JH-H ) 7.5 Hz, 4H, tol), 6.53 (d, JH-H ) 7.5
Hz, 4H, tol), 6.28 (br s, 4H, NH2), 2.23 (t, JP-H ) 12.5 Hz, 3H,
NMe), 2.10 (s, 6H, tol). Anal. Calcd (found) for C41H41F6N3O6P2-
PdS2: C, 48.37 (48.37); H, 4.06 (4.03); N, 4.13 (4.14).
3
3
tol), 5.60 (d, JH-H ) 7.5 Hz, 4H, tol), 1.82 (s, 6H, tol), 0.89 (t,
3JP-H ) 15 Hz, 6H, CMe2), 1.18 (t, 3JP-H ) 15 Hz, 6H, CMe2). 19
F NMR (THF): -78.9 (s, OTf).
[(dppma)Pd(NH2-2,6-xylyl)2](NO3)2 (8). To a stirred suspension
of (dppma)PdCl2 (0.100 g, 0.174 mmol) in 10 mL of CH2Cl2 is
added AgNO3 (0.060 g, 0.35 mmol). The mixture is stirred for 3
h. The AgCl precipitate is removed by filtration through diatoma-
ceous earth. The resulting clear filtrate is concentrated under reduced
pressure to 3 mL, and to this clear solution is added 2,6-
dimethylaniline (0.085 g, 0.69 mmol) in 2 mL of CH2Cl2. The
homogeneous solution is stirred overnight and layered with an equal
amount of toluene to obtain the deep yellow solid product. Yield:
0.120 g (79%). 31P{1H} NMR (CH2Cl2): 26.7 (s). 1H NMR (CD2-
[Pd(µ-N-2,6-xylyl)(dppma)]2‚LiNO3 (11) (M ) Pd). The
procedure is the same as that used for the Pt analogue. Yield: 0.040
g (53%) of red crystals. 31P {1H} NMR (DME): 52.2 (s). 1H NMR
data could not be obtained as the complex is either insoluble or
decomposes in all common deuterated NMR solvents (including
cold CD2Cl2). Crystals for the X-ray analysis were grown as
described for the Pt analogue.
Crystal Structure Analyses. Crystal data and refinement results
are given in Tables 1 and 2. CIF files are supplied as Supporting
Information. Crystals were grown as described in the syntheses
given above and were mounted by pipetting the crystals and mother
liquor into a pool of heavy oil. A suitable crystal was selected and
removed from the oil with a glass fiber. With the oil-covered crystal
adhering to the end of the glass fiber the sample was transferred to
an N2 cold stream on the diffractometer and data were collected at
-100 °C. Data reduction and processing followed routine proce-
dures. Structures were solved by direct methods and refined on
3
Cl2): 7.77-7.52 (m, 20H, Ph), 6.82 (d, JH-H ) 7.5 Hz, 4H,
3
m-xylyl-H), 6.50 (t, JH-H ) 7.5 Hz, 2H, p-xylyl-H), 3.62 (br s,
4H, NH2), 2.40 (t, 3JP-H ) 12.5 Hz, 3H, N-Me), 2.08 (s, 12H, 2,6-
Me2). Anal. Calcd (found) for C41H45N5O6P2Pd: C, 56.47 (56.26);
H, 5.21 (5.40); N, 8.04 (8.12).
[{Pd(µ-N-4-tol)(dppma)}2‚Li(DME)](X) (9) (M ) Pd; Ar )
4-tol; X ) BF4, OTf). LiN(SiMe3)2 (0.066 g, 0.39 mmol) in 5 mL
of DME was added dropwise to a stirred suspension of [Pd(NH2-
4-tol)2(dppma)](X)2 (0.100 g) in 10 mL of DME. On addition of
base, the suspension slowly turns from yellow to orange and then
to red, and after complete addition the mixture becomes a deep
red solution. The deep red solution is stirred for 1 h, concentrated,
and stored at -30 °C to obtain the red solid product. X ) BF4:
yield 0.040 g (51%); 31P{1H} NMR (DME) 50.7 (s); 1H NMR (CD2-
2
Fo .
Acknowledgment. This work was supported by the
Division of Chemical Sciences, Office of Basic Energy
Sciences, Office of Energy Research, U.S. Department of
Energy (Grant DE-FG02-88ER13880). A grant from the
National Science Foundation (9221835) provided a portion
of the funds for the purchase of the NMR equipment. We
thank Dr. Charles Barnes and Dr. Alan James for assistance
with the crystal structure determinations.
3
Cl2, -20 °C) 7.58-6.94 (m, 40H, Ph), 6.26 (d, JH-H ) 7.5 Hz,
4H, tol), 5.30 (d, JH-H ) 7.5 Hz, 4H, tol), 3.52 (s, 4H, DME),
3
3
3.01 (s, 6H, DME), 2.17 (t, JP-H ) 12.5 Hz, 6H, NMe), 2.07 (s,
6H, tol). X ) OTf: yield 0.040 g (56%); 31P{1H} NMR (DME)
52.1 (s); 1H NMR (CD2Cl2, -20 °C) 7.58-6.95 (m, 40H, Ph), 6.42
3
3
(d, JH-H ) 7.5 Hz, 4H, tol), 5.90 (d, JH-H ) 7.5 Hz, 4H, tol),
3.50 (s, 4H, DME), 3.12 (br s, 6H, DME), 2.21 (br t, 3JP-H ) 12.5
Hz, 6H, NMe), 2.05 (s, 6H, tol). Anal. Calcd (found) for C69H70F3-
LiN4O5P4SPd2: C, 51.24 (51.20); H, 4.81 (4.79); N, 3.88 (3.95).
[Pd(µ-N-4-tol)(dppip)]2‚LiN(SiMe3)2 (10) (M ) Pd, Ar )
4-tol). To the stirred suspension of [Pd(NH2-4-tol)2(dppip)](OTf)2
Supporting Information Available: Crystallographic informa-
tion files (CIF) for structures 2, 7 (L2 ) dppma, dppip), 9-11, and
Pd(OTf)2(dppma). This material is available free of charge via the
Internet at http://pubs.acs.org.
IC025987F
Inorganic Chemistry, Vol. 42, No. 4, 2003 1295