Chemistry of P,N-ligated methylpalladium(II) alkoxide complexes: Syntheses, structural features in the solid state and in solution, and hydrogen-bond formation

Article abstract of DOI:10.1021/om950661i

The reaction of P,N-ligated dimethylpalladium(II) complexes [Pd(Me)₂(P～N)] [P～N = o-(diphenylphosphino)-N,N-dimethylbenzylamine (PCN), (diphenylphosphino)-N-N-dimethylethyleneamine (PN)] with an equimolar amount of HOCH(CF₃)₂

Full text of DOI:10.1021/om950661i

Organometallics 1996, 15, 1405-1413
1405
Ch em istr y of P ,N-Liga ted Meth ylp a lla d iu m (II) Alk oxid e
Com p lexes: Syn th eses, Str u ctu r a l F ea tu r es in th e Solid
Sta te a n d in Solu tion , a n d Hyd r ogen -Bon d F or m a tion
Gerardus M. Kapteijn,† Marieke P. R. Spee,† David M. Grove,† Huub Kooijman,‡
Anthony L. Spek,‡,§ and Gerard van Koten*,†
Department of Metal-Mediated Synthesis, Debye Institute, and Crystal and Structural
Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University,
Padualaan 8, 3584 CH Utrecht, The Netherlands
Received August 23, 1995X
The reaction of P,N-ligated dimethylpalladium(II) complexes [Pd(Me)2(P∼N)] [P∼N )
o-(diphenylphosphino)-N,N-dimethylbenzylamine (PCN), (diphenylphosphino)-N,N-dimeth-
ylethyleneamine (PN)] with an equimolar amount of HOCH(CF3)2 or HOC6H4-4-X (X ) H,
Cl, OMe, Me, CN, NO2, OH) affords methylpalladium(II) alkoxide and aryl oxide complexes
[Pd(Me)(OR)(P∼N)] [R ) CH(CF3)2, C6H4-4-X; P∼N ) PCN, PN], which have been isolated
in high yields as white or pale orange solids. NMR spectroscopic data indicate that the
complexes have the alkoxide or aryl oxide ligand (OR) positioned trans with respect to the
P-atom. Reaction of [Pd(Me)2(PCN)] with 2 equiv of phenol affords the phenol adduct [Pd-
(Me)(OC6H5)(PCN)]‚HOC6H5, which has been isolated as a white solid. The transesterifi-
cation reaction of [Pd(Me)(OC6H5)(PCN)] with C6H5SC(O)Me affords the arenethiolate
complex [Pd(Me)(SC6H5)(PCN)]. Furthermore, the alkoxide complex [Pd(Me)(OCH(CF3)2)-
(PN)] reacts with phenylacetylene to afford an isolable alkynylpalladium(II) complex [Pd-
(Me)(CtCPh)(PN)]. Thermolysis of the latter complex results in reductive elimination of
MeCtCPh in 98% yield. When this reductive elimination is performed under a CO
atmosphere, MeCtCPh (87%) is formed together with small amounts of the insertion product,
MeC(O)CtCPh (3%). Crystals of [Pd(Me)(OC6H5)(PCN)]‚CH2Cl2 and its adduct with HOC6H5
have been subjected to X-ray diffraction studies. The molecular structure of the latter adduct
shows an OsH‚‚‚O hydrogen bond between the phenol and the oxygen atom of the phenoxide
3
unit. The 31P NMR chemical shift and J H,P for the PdsCH3 group of the complexes [Pd-
(Me)(OC6H4-4-X)(PN)] have been correlated with various Hammet substituent constants;
the best linearity was achieved with parameters that represent the sum of resonance and
inductive/field effects of the substituent X.
In tr od u ction
to-oxygen bond is weak, particularly when the other
ligands are mono- or bidentate tertiary amines.4 How-
ever, it is now recognized that the metal-to-oxygen bond
can be of comparable strength or even stronger than the
metal-to-carbon(sp3) bond.5
One reason for the recent interest in the chemistry
of late transition metal alkoxides is that such complexes
have been postulated as intermediates in various metal
complex-catalyzed synthetic organic reactions.1 Ex-
amples of alkoxypalladium-catalyzed processes include
not only the copolymerization of CO and olefins to
produce polyketones2 but also the methoxycarbonylation
of propyne to give methyl methacrylate.3 Research in
late transition metal alkoxide chemistry may have been
limited by the earlier belief that the transition metal-
Reported interesting properties of late transition
metal alkoxides include CsO bond formation,6 inser-
tion of small molecules into the metal-to-oxygen bond,7
â-hydrogen elimination of the alkoxide ligand to release
aldehydes or ketones,8 and their ability to associate with
alcohols through OsH‚‚‚O hydrogen bonding.9 In the
course of our study concerning palladium alkoxides,10
we have reported both the synthesis and properties of
methylpalladium(II) alkoxides (and their adducts with
* Author to whom correspondence should be addressed.
† Debye Institute.
‡ Bijvoet Center for Biomolecular Research.
(4) (a) Mayer, J . M. Comments Inorg. Chem. 1988, 8, 125. (b)
Evidence has been obtained for alkoxide π-donation to an Ir(III)
center: Lunder, D. M.; Lobkovsky, E. B.; Streib, W. E.; Caulton, K. G.
J . Am. Chem. Soc. 1991, 113, 1837.
§ Address correspondence pertaining to crystallographic studies to
this author.
X Abstract published in Advance ACS Abstracts, February 1, 1996.
(1) (a) Tsuji, J .; Minami, I. Acc. Chem. Res. 1987, 20, 140. (b)
Bryndza, H. E.; Tam, W. Chem. Rev. 1988, 88, 1163. (c) Venanzi, L.
M.; Gorla, F. Helv. Chim. Acta 1990, 73, 690. (d) Alper, H.; Ali, B. J .
Mol. Catal. 1991, 67, 29. (e) Barbaro, P.; Bianchini, C.; Frediani, P.;
Meli, A.; Vizza, F. Inorg. Chem. 1992, 31, 1523. (f) Sen, A.; Lin, M.;
Kao, L.-C.; Hutson, A. C. J . Am. Chem. Soc. 1992, 114, 6385. (g)
Carpentier, J . F.; Castanet, Y.; Mortreux, A.; Petit, F. J . Organomet.
Chem. 1994, 482, 31.
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J . J . Am. Chem. Soc. 1984, 106, 4369. (b) Ba¨ckvall, J . E.; Bjorkman,
E. E.; Petterson, L.; Siegbahn, R. J . J . Am. Chem. Soc. 1985, 107, 7265.
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Organometallics 1990, 9, 12. (b) Thompson, J . S.; Bernard, K. A.;
Rappoli, B. J .; Atwood, J . D. Organometallics 1990, 9, 2727. (c) Glueck,
D. S.; Newman Winslow, L. J .; Bergman, R. G. Organometallics 1991,
10, 1462. (d) Thompson, J . S.; Randall, S. L.; Atwood, J . D. Organo-
metallics 1991, 10, 3906. (e) Alsters, P. L.; Boersma, J .; van Koten,
G. Tetrahedron Lett. 1991, 32, 675. (f) Alsters, P. L.; Boersma, J .;
Smeets, W. J . J .; Spek, A. L.; van Koten, G. Organometallics 1993,
12, 1639. (g) Hoffman, D. M.; Lappas, D.; Wierda, D. A. J . Am. Chem.
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Chem. 1990, 417, 235.
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Organometallics 1994, 475, 57.
0276-7333/96/2315-1405$12.00/0 © 1996 American Chemical Society

1406 Organometallics, Vol. 15, No. 5, 1996
Kapteijn et al.
alcohols) containing bidentate N-donor ligands,11 as well
as the reaction of CO with N-ligated methylpalladium
methoxides that affords stable methylpalladium meth-
oxycarbonyl complexes.12 These studies and the use of
P,N-ligating ligands in the palladium methoxide-
catalyzed production of methyl methacrylate3 encour-
aged us to use bidentate P,N-donor ligands in palladium
alkoxide chemistry. Here, we report full details of our
study on the synthesis, properties, and reactivity of P,N-
ligated methylpalladium(II) alkoxides and aryl oxides,
which includes the formation of OsH‚‚‚O hydrogen-
bonded adducts and alkynylpalladium(II) complexes. In
this study, P,N-ligated palladium complexes have been
prepared with variously substituted aryl oxide ligands
to examine correlations of the 31P NMR chemical shift
F igu r e 1. Schematic representation of the P,N-ligated
complexes 1 and 2.
(diphenylphosphino)-N,N-dimethylethyleneamine (PN)
affords the known complex [Pd(Me)2(PCN)] (1)13a and
the new dimethylpalladium complex [Pd(Me)2(PN)] (2)
(see Figure 1), which have been used as starting
materials for the preparation of new methylpalladium-
(II) alkoxide and aryl oxide complexes.
Reaction of 1 with organic compounds ROH in a 1:1
molar ratio affords new complexes of the type [Pd(Me)-
(OR)(PN)] (3-10) (see eq 1). This reaction, in which CH4
3
and J H,P with various Hammet constants for the ring
substituent.
Resu lts a n d Discu ssion
P r ep a r a tion of Meth ylp a lla d iu m (II) Alk oxid e
a n d Ar yl Oxid e Sp ecies 3-13. In previous papers
from our laboratory, it has been shown that dimeth-
ylpalladium(II) complexes containing N,N,N′,N′-tetra-
methylethylenediamine (tmeda) easily undergo ligand
exchange reactions.13 Exchange of the tmeda in [Pd-
(Me)2(tmeda)] for the P,N-chelating ligands o-(diphe-
nylphosphino)-N,N-dimethylbenzylamine (PCN) and
(7) (a) Kim, Y.-J .; Osakada, K.; Sugita, K.; Yamamoto, T.; Yama-
moto, A. Organometallics 1988, 7, 2182. (b) Hartwig, J . F.; Bergman,
R. G.; Andersen, R. A. J . Am. Chem. Soc. 1991, 113, 6499. (c) Simpson,
R. D.; Bergman, R. D. Organometallics 1992, 11, 4306. (d) Mandal,
S. K.; Ho, D. M.; Orchin, M. Organometallics 1993, 12, 1714. (e) Tsuji,
J .; Mandai, T. J . Organomet. Chem. 1993, 451, 15. (f) Smith, J . D.;
Hansson, B. E.; Merola, J . S.; Waller, F. J . Organometallics 1993, 12,
568. (g) To´th, I.; Elsevier, C. J . J . Chem. Soc., Chem. Commun. 1993,
529. (h) Bertani, R.; Cavinato, G.; Tonioli, L.; Vasapollo, G. J . Mol.
Catal. 1993, 84, 165. (i) Vasapollo, G.; Tonioli, L.; Cavinato, G.; Bigoli,
F.; Lanfranchi, M.; Pellinghelli, M. A. J . Organomet. Chem. 1994, 481,
173. (j) Elsevier, C. J . J . Mol. Catal. 1994, 92, 285.
(8) (a) Bernard, K. A.; Rees, W. M.; Atwood, J . D. Organometallics
1986, 5, 390. (b) Bryndza, H. E.; Calabrese, J . C.; Marsi, M.; Roe, D.
C.; Tam, W.; Bercaw, J . E. J . Am. Chem. Soc. 1986, 108, 4805. (c)
Goldman, A. S.; Halpern, J . J . Am. Chem. Soc. 1987, 109, 7537. (d)
Hoffman, D. M.; Lappas, D.; Wierda, D. A. J . Am. Chem. Soc. 1993,
115, 10538. (e) Blum, O.; Milstein, D. Angew. Chem., Int. Ed. 1995,
34, 229.
is the byproduct, has proved successful for 1,1,1,3,3,3-
hexafluoro-2-propanol and the aryl alcohols HOC6H4-
4-X (X ) H, Cl, OMe, Me, CN, NO2, OH). The meth-
ylpalladium(II) alkoxide and aryl oxide complexes 3-10
have been isolated in moderate-to-good yields as white
or pale orange crystalline solids, which are thermally
stable at room temperature. A similar reaction of [Pd-
(Me)2(PCN)] (2) with 1 equiv of an aryl alcohol leads to
the formation of aryl oxide and alkoxide complexes of
the type [Pd(Me)(OR)(PCN)] (11-13) (see eq 2). By
(9) (a) Kegley, S. E.; Schaverien, C. J .; Freudenberger, J . H.;
Bergman, R. G.; Nolan, S. P.; Hoff, C. D. J . Am. Chem. Soc. 1987, 109,
6563. (b) Kim, Y.-J .; Osakada, K.; Yamamoto, A. Bull. Chem. Soc. J pn.
1989, 62, 964. (c) Di Bugno, C.; Pasquali, M.; Leoni, P.; Sabatino, P.;
Braga, D. Inorg. Chem. 1989, 28, 1390. (d) Osakada, K.; Kim, K.-Y.;
Yamamoto, A. J . Organomet. Chem. 1990, 382, 303. (e) Kim, Y.-J .;
Osakada, K.; Takenaka, A.; Yamamoto, A. J . Am. Chem. Soc. 1990,
112, 1096. (f) Osakada, K.; Oshiro, K.; Yamamoto, A. Organometallics
1991, 10, 404. (g) Seligson, A. L.; Cowan, R. L.; Trogler, W. C. Inorg.
Chem. 1991, 30, 1096. (h) Seligson, A. L.; Cowan, R. L.; Trogler, W.
C. Inorg. Chem. 1991, 30, 3371. (i) Osakada, K.; Kim, Y.-J .; Tanaka,
M.; Ishiguro, S.-I.; Yamamoto, A. Inorg. Chem. 1991, 30, 197. (j)
Simpson, R. D.; Bergman, R. G. Organometallics 1993, 12, 781. (k)
Ozawa, F.; Yamagami, I.; Yamamoto, A. J . Organomet. Chem. 1994,
473, 265.
(10) (a) Alsters, P. L.; Baesjou, P. J .; J anssen, M. D.; Kooijman, H.;
Sicherer-Roetman, A.; Spek, A. L.; van Koten, G. Organometallics 1992,
11, 4124. (b) Kapteijn, G. M.; Grove, D. M.; Smeets, W. J . J .; Spek, A.
L.; van Koten, G. Inorg. Chim. Acta 1993, 207, 131. (c) Hunter, C. A.;
Lu, X.-J .; Kapteijn, G. M.; van Koten, G. J . Chem. Soc., Faraday Trans.
1995, 91, 2009.
means of X-ray crystallography and NMR spectroscopy
(vide infra), it has been unambiguously established that
in these PN- and PCN-ligated complexes the alkoxide
or aryl oxide ligand is positioned trans with respect to
the P-donor atom.
Rea ctivity of th e P CN Com p lexes 2 a n d 4. The
reaction of [Pd(Me)2(PCN)] (2) with 2 equiv of phenol
leads to the formation of an adduct formulated as [Pd-
(Me)(OC6H5)(PCN)]‚HOC6H5 (14) (see eq 3). This alcohol-
(11) (a) Kapteijn, G. M.; Dervisi, A.; Grove, D. M.; Kooijman, H.;
Lakin, M. T.; Spek, A. L.; van Koten, G. J . Am. Chem. Soc. 1995, in
press. (b) Kim, Y.-J .; Choi, J .-C.; Osakada, K. J . Organomet. Chem.
1995, 491, 97.
(12) Kapteijn, G. M.; Verheof, M. J .; van den Broek, M. A. F. H.;
Grove, D. M.; van Koten, G. J . Organomet. Chem. 1995, 53, C26-C28.
(13) (a) de Graaf, W.; Boersma, J .; Smeets, W. J . J .; Spek, A. L.;
van Koten, G. Organometallics 1989, 8, 2907. (b) de Graaf, W.;
Boersma, J .; van Koten, G. Organometallics 1990, 9, 1479. (c) Markies,
B. A.; Rietveld, M. H. P.; Boersma, J .; Spek, A. L.; van Koten, G. J .
Organomet. Chem. 1992, 424, C12.
associated complex has been isolated as a yellow-orange
crystalline solid (79%). The phenol-free complex 4

P,N-Ligated Methylpalladium(II) Alkoxide Complexes
Organometallics, Vol. 15, No. 5, 1996 1407
cannot be regenerated from adduct 14 by washing
procedures, and this illustrates the stability of the
OsH‚‚‚O hydrogen bond in this adduct. By means of
X-ray crystallography and NMR spectroscopy (vide
infra), it has proved possible to unambiguously establish
that adduct 14 has strong OsH‚‚‚O hydrogen bonding
both in the solid state and in solution. Analogous
alcohol adducts of palladium alkoxide complexes con-
taining bidentate N-donor ligands11 and P-donor ligands9
have been isolated as solids that are thermally stable
at room temperature.
Reaction of [Pd(Me)(OC6H5)(PCN)] (4) with an equimo-
lar amount of the thioester C6H5SC(O)Me proceeds
smoothly at room temperature to give the arenethiolate
complex [Pd(Me)(SC6H5)(PCN)] (15), which has been
isolated in 70% yield, and the carboxylic ester C6H5OC-
(O)Me (see eq 4). Similar transesterification reactions
F igu r e 2. ORTEP (30% probability level) drawing of 12.
Hydrogen atoms and the dichloromethane solvate molecule
are omitted for clarity.
with methylpalladium alkoxide complexes containing
mono- and bidentate P-donor ligands have been reported
by Kim et al.9e
Rea ctivity of Alk oxid e Com p lexes w ith P h en yl-
a cetylen e. Reaction of the P,N-ligated palladium
alkoxide complex [Pd(Me)(OCH(CF3)2)(PN)] (4) with
phenylacetylene produces the alkynyl complex [Pd(Me)-
(CtCPh)(PN)] (16), which was isolated in 86% yield (see
eq 5). To extend the scope of this reaction, we also used
F igu r e 3. ORTEP (30% probability level) drawing of 14.
Hydrogen atoms are omitted for clarity.
the bidentate N-donor-ligated palladium alkoxide com-
plex [Pd(Me)(OCH(CF3)2)(tmeda)] as the starting mate-
rial, and this species when treated with phenylacetylene
affords the alkynyl complex [Pd(Me)(CtCPh)(tmeda)]
(17). The latter complex is not thermally stable in
CHCl3 solution, and above 0 °C it decomposes within a
few minutes.
Recently, it was reported that methylpalladium(II)
alkynyl complexes with bidentate P-donor ligands can
be formed by the reaction of methylpalladium(II) alkox-
ide complexes with acetylenes, and reductive elimina-
tion reactions of these alkynyl complexes were de-
scribed.14
Molecu la r Str u ctu r es of th e P CN Meth ylp a lla -
d iu m P h en oxid e Com p lex 12 a n d Its P h en ol Ad -
d u ct 14. Figures 2 and 3 show the molecular structures
of [Pd(Me)(OC6H5)(PCN)] (12) and its phenol adduct
[Pd(Me)(OC6H5)(PCN)]‚HOC6H5 (14), respectively. The
crystal structure of 12 also contains one non-coordinat-
ing dichloromethane solvate molecule in the asymmetric
unit. Selected bond lengths and angles are summarized
in Table 1.
Both 12 and 14 possess palladium atoms with an
approximate square-planar coordination geometry, in
which the phenoxide unit is positioned trans with
respect to the P-atom. Adduct 14 shows the association
of a phenol molecule to the phenoxide ligand through
OsH‚‚‚O hydrogen bonding (O‚‚‚O ) 2.624(5) Å, O-
H‚‚‚O ) 175(8)°). Hydrogen bonds can be considered
An interesting point is that the synthetic procedure
for 16 and 17 does not give other alkynylpalladium(II)
complexes, such as [Pd(OCH(CF3)2)(CtCPh)L2] or [Pd-
(CtCPh)2L2] (L2 ) PN or tmeda), that might be formed
by protonation of the methyl ligand. Furthermore,
insertion of the CtC unit into the PdsO bond does not
occur, although several insertions of unsaturated com-
pounds into MsO bonds have been reported.15 We
believe that the operative mechanism is probably con-
certed, with the driving force being the formation of the
PdsCacetylide bond; we consider an oxidative addition of
phenylacetylene unlikely, and a nucleophilic substitu-
tion mechanism does not seem feasible since the pKa
values of PhCtCH and hexafluoro-1-methylethanol are
ca. 20 and 10, respectively. Thermolysis of 16 and 17
affords methylphenylacetylene as the only organic
product (>98%) (see eq 6), whereas thermolysis of 16
and 17 in the presence of CO affords not only meth-
ylphenylacetylene but also small amounts ((3%) of the
insertion product MeC(O)CtCPh (see eq 7).
(14) Kim, Y.-J .; Osakada, K.; Yamamoto, A. J . Organomet. Chem.
1993, 452, 247.
(15) (a) Bryndza, H. E.; Calabrese, J . C.; Wreford, S. S. Organome-
tallics 1984, 3, 1603. (b) Woerpel, K. A.; Bergman, R. G. J . Am. Chem.
Soc. 1993, 115, 7888.

1408 Organometallics, Vol. 15, No. 5, 1996
Kapteijn et al.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d Bon d
An gles (d eg) for [P d (Me)(OC6H5)(P CN)] (12)
(CH2Cl2 Solva te) a n d Its P h en ol Ad d u ct
[P d (Me)(OC6H5)(P CN)]‚HOC6H5 (14)a
12
14
Bond Distances
2.088(5)
PdsO(1)
PdsC(22)
PdsN(1)
2.103(2)
2.024(5)
2.223(3)
2.1949(11)
1.318(4)
1.354(6)
2.624(5)
F igu r e 4. Intramolecular exchange of coordinated alkox-
ide and associated alcohol.
2.020(7)
2.205(5)
2.1900(16)
1.317(8)
PdsP(1)
lengthening. Association of a phenol causes a further
lengthening of the Pd-O bond by ∼0.015(5) Å; similar
elongations of the Pd-O bond upon phenol adduct
formation have been reported by ourselves for [Pd(Me)-
(OC6H4X-4)(tmeda)] (X ) H, NO2)11a and by others for
trans-[Pd(Me)(OC6H5)(PMe3)2].9e
C(23)sO(1)
C(29)sO(2)
O(1)‚‚‚O(2)
Bond Angles
122.6(4)
PdsO(1)sC(23)
P(1)sPdsN(1)
P(1)sPdsC(22)
P(1)sPdsO(1)
N(1)sPdsC(22)
O(2)sH‚‚‚O(1)
122.3(2)
92.24(8)
91.25(14)
178.12(7)
174.38(18)
175(8)
92.19(13)
92.3(2)
178.87(15)
173.8(2)
Solu tion Beh a vior of P N Alk oxid e Com p lexes 2
a n d 18. Addition of 1 equiv of HOCH(CF3)2 to the
alkoxide complex [Pd(Me)(OCH(CF3)2)(PN)] (2) in tolu-
ene leads to the in situ formation of an OsH‚‚‚O
hydrogen-bonded adduct [Pd(Me)(OCH(CF3)2)(PN)]‚
HOCH(CF3)2 (18), but so far it has not proved possible
to isolate this adduct as a solid (see Experimental
a
Numbers in parentheses are estimated standard deviations
in the least significant digits.
strong when the O‚‚‚O distance falls in the range 2.50-
2.65 Å for approximately linear OsH‚‚‚O,16 and on this
basis we conclude that the hydrogen bond in 14 is
reasonably strong. Furthermore, the O‚‚‚O distance in
14 is comparable to O‚‚‚O distances in both hydrogen-
bonded organic molecules17 and related palladium alkox-
ide and aryl oxide adducts.9-11
1
Section). The H NMR spectrum of adduct 18 formed
in situ in toluene-d8 (25 °C) shows the OH hydrogen of
the associated alcohol at 8.05 ppm, and such a low-field
position is characteristic for a transition metal alcohol
adduct.9,11 Further, the spectrum shows, at 4.65 ppm,
one well-resolved septet corresponding to the OCH
hydrogens of both the fluorinated alkoxide unit (PdsOR)
and the associated alcohol (ROH). Cooling of this
solution of 18 to 200 K causes this resonance to split
into two separate OCH signals for the alkoxide and the
alcohol unit at δ 4.73 and 4.90, respectively; the
coalescence temperature is (243 K, with ∆G# of ca. 12
The molecular structure of 14 also reveals the pres-
ence of a possible electrostatic CsH‚‚‚O interaction (not
illustrated in Figure 3) of one NMe group with the
oxygen of the palladium-bonded OC6H5 unit [C(2)‚‚‚O-
(1) ) 3.130(5) Å; C(2)sH(2B)‚‚‚O(1) ) 122(2)°]. Similar
features not illustrated in Figure 2 are also present in
the molecular structure of the dichloromethane adduct
12. Namely, a close intramolecular contact between the
NMe group and the oxygen atom of the phenoxide unit
[C(2)‚‚‚O(1) ) 3.064(9) Å; C(2)sH(2B)‚‚‚O(1) ) 126(3)°]
and close intermolecular contacts between the two
dichloromethane methylene hydrogens and the oxygen
atom of the phenoxide unit [C(29)‚‚‚O(1) ) 3.160(12) Å;
C(29)sH(29A)‚‚‚O(1) ) 109.3(13) and C(29)sH(29B)‚‚‚O-
(1) ) 109.7(18)°]. We have reported earlier examples
of CsH‚‚‚O interactions in the N-ligated palladium
kcal mol-1
. This behavior can be explained by an
intramolecular exchange of coordinated alkoxide and
associated alcohol, as illustrated in Figure 4, which is
fast on the NMR time scale at room temperature.
Unfortunately, we were not able to determine the
detailed thermodynamic parameters for this alkoxide-
alcohol exchange in 18 due to the small separation of
(50 Hz for the OCH hydrogens of the alkoxide and
alcohol units at low temperature.
Kim et al. found for [Pd(Me)(OCH(CF3)(Ph))(PMe3)2]‚
HOCH(CF3)(Ph) (an adduct with phosphine ligands that
bears analogy to adduct 18) that the OCH hydrogens
of the alkoxide and alcohol coalesce at 273 K, and their
conclusion, based upon thermodynamic data, likewise
is that an intramolecular alkoxide-alcohol exchange
mechanism is operative.9e We and others have studied
the temperature dependence of the OH hydrogen for
these alcohol adducts of palladium alkoxides and aryl
oxides (i.e., measurement of palladium alkoxide-alcohol
association equilibria), and it was possible to quantify
the OsH‚‚‚O hydrogen bond in palladium alkoxide
adducts as strong (∆H° ) 20-34 kJ mol-1).9a,e,10a,11a
Solu tion Beh a vior of P CN Com p lexes 11 a n d 12.
1H NMR spectra (benzene-d6) of the PCN complexes [Pd-
(Me)(OCH(CF3)2)(PCN)] (11) and [Pd(Me)(OC6H5)(PCN)]
(12) at 300 K show broad resonances at approximately
δ 2.80 and 2.40, assigned to the NCH2 and NMe2 groups,
respectively. Models of these complexes show that
because of chelate ring puckering the two N-methyl
groups, the benzylic protons, and the PPh2 phenyl
groups are diastereotopic. Upon cooling of solutions of
11 and 12 in toluene-d8, the resonance of the NMe2
alkoxide complexes [Pd(OCH(CF3)2)(OC6H5)(bpy)]‚
10b
HOC6H5
and [Pd(Me)(OCH(CF3)2)(tmeda)].11a One
might conclude that this type of interaction is important
in stabilizing late transition metal alkoxide or aryl oxide
adducts and could be termed a steering interaction,
which, although small in energy (4-8 kJ mol-1), is
sufficient to select a preferred molecular conformation.18
The Pd-O distances in 12 and 14 (2.088(5) and 2.103-
(2) Å, respectively) are longer than the PdsO distances
that we have found in the related N-donor-ligated
complex [Pd(Me)(OC6H5)(tmeda)] and its HOC6H5 ad-
duct (2.024(3) and 2.037(2) Å, respectively).11a It is the
presence of a P-donor atom trans to the phenoxide unit
that is probably the most important reason for this
(16) Gille, P.; Bertolasi, V.; Ferritti, V.; Gilli, G. J . Am. Chem. Soc.
1994, 116, 909.
(17) (a) Schuster, P., Zundel, G., Sandorfy, C., Eds.; The Hydrogen
Bond; North Holland: Amsterdam, 1976. (b) J oesten, M. D.; Schaad,
L. J . Hydrogen Bonding; Marcel Dekker: New York, 1974. (c)
Pimentel, G. C.; McLellan, A. L. The Hydrogen Bond; W. H. Freeman:
San Francisco, CA, 1960.
(18) (a) Desiraju, G. R. Acc. Chem. Res. 1991, 24, 290. (b) Chloro-
form and dichloromethane can form CsH‚‚‚O bonds, see: Green, R.
D. Hydrogen Bonding in C-H Groups; MacMillan: London, 1974.

P,N-Ligated Methylpalladium(II) Alkoxide Complexes
Organometallics, Vol. 15, No. 5, 1996 1409
F igu r e 5. Conformational interconversion of the coordi-
nated PCN ligand.
3
F igu r e 7. Plot of J H,P versus σp. For data see Table 2.
Ta ble 3. Cor r ela tion Coefficien ts for Ha m m ett
Su bstitu en t P a r a m eter s w ith NMR Sp ectr a l Da ta
correlation coefficient
substituent
constant
δ
31P
3J H,P
σp
0.98
0.90
0.98
0.73
0.61
0.96
0.89
0.97
0.50
0.70
F igu r e 6. Plot of 31P chemical shift versus σp. For data
+
σp
-
see Table 2.
σp
F
R
Ta ble 2. NMR Sp ectr a l Da ta for P a r a -Su bstitu ted
Ar yl Oxid e Com p lexes [P d (Me)(OC6H4X-4)(P N)]
(4-10)a
This result indicates that the sum of resonance and
inductive/field effects of the substituent directly influ-
ence the two chosen NMR parameters. The Hammet
constant σp-, which reflects the effect that a ring
substituent has on a reaction that results in an increase
in negative charge in the transition state, exhibits a
complex
X
3J H,P (Hz)b
31P (ppm)
4
5
6
7
8
H
OMe
Me
2.48
2.55
2.55
2.39
2.17
2.01
2.71
48.68
48.39
48.56
49.13
49.71
50.15
Cl
good correlation with the 31P NMR shift and J H,P (see
3
CN
NO2
OH
9
10
Table 3). This is logical since the aromatic ring of the
aryl oxide in these complexes has anionic character, and
one also sees a low correlation of 31P NMR shift and
3J H,P with the Hammet constant σp+. The poor correla-
tions obtained for the Taft field and resonance con-
stants, F and R, again emphasize that it is a combina-
tion of both resonance and inductive/field effects that
influences the NMR parameters. Although the influ-
ence of the para substituents is not large, the preceding
results can be explained with a simple model. In this
model, the electron-donating substituents on the aryl
oxide unit increase the net negative charge on the
aromatic ring, which shifts some of the increased charge
to the palladium atom.20 This extra negative charge
placed on the metal is now available for donation to the
π*-orbital of the P-atom, and this results in a high-field
shift in 31P NMR. This increase in electron density
a
b
Measured in CD3COCD3. PdMe group ((0.07 Hz).
group splits into two lines (∆δ ) 78 Hz, ∆G# ) 10 kcal
mol-1). We believe that this temperature dependent
behavior is a consequence of the conformational inter-
conversion shown in Figure 5, which may be described
as resulting from a partial rotation (wagging) of the
aromatic ring around the P-Ar bond axis. Rauchfuss
et al. reported a similar fluxional behavior of the PCN
ligand in the complex [RhCl(CO)(PCN)], for which an
activation energy of 8.8 kcal mol-1 was calculated.19
Cor r ela tion of NMR Da ta w ith Ha m m et Su b-
stitu en t Con sta n ts. Relevant 31P NMR chemical shift
data and values of 3J H,P for the PdMe group positioned
cis to the P-donor atom in the palladium aryl oxide
complexes [Pd(Me)(OC6H4-4-X)(PN)] (4-10) are sum-
marized in Table 2. The plot and line fitting for the
between P and Pd is probably also the cause of an
increase in J P,H
3
.
3
31P NMR shift and J H,P versus the Hammet constant
Con clu d in g Rem a r k s. The results presented in
this paper illustrate that bidentate P,N-donor ligands
are suitable for stabilizing methylpalladium(II) species
with alkoxide or aryl oxide ligands and that these
species have a strong tendency to form adducts with
alcohols. These new alkoxide complexes furthermore
are useful starting materials for the preparation of
alkynyl and thiolate palladium(II) complexes. Further
studies are in progress to investigate the potential of
these complexes in synthetic studies and catalytic
processes.
σp (see Figures 6 and 7, respectively) show that more
electron-withdrawing para substituents result in an
3
increase of the δ 31P and a decrease in J H,P. To obtain
more detailed insight, we have correlated our NMR data
3
(δ 31P NMR and J H,P) for the complexes 4-10 versus
several specific substituent constants,20 and the corre-
sponding correlation coefficients obtained are shown in
Table 3.
Examination of both NMR data sets shows that the
best linearity is obtained for the σp and σp- parameters.
Exp er im en ta l Section
(19) Rauchfuss, T. B.; Patino, F. T.; Roundhill, D. M. Inorg. Chem.
1975, 14, 652.
(20) Hansch, C.; Leo, A.; Taft, W. R. Chem. Rev. 1991, 91, 165.
(21) Blais, M. S.; Rausch, M. D. Organometallics 1994, 13, 3557.
Gen er a l Con sid er a tion s. Reactions were performed in
an atmosphere of nitrogen using standard Schlenk techniques.

1410 Organometallics, Vol. 15, No. 5, 1996
Kapteijn et al.
C6H6, Et2O, and pentane were freshly distilled from sodium
benzophenone ketyl. CH2Cl2 was distilled from CaH2. All
other solvents were used as received. The solvent acetone (p.a.)
and the materials 1,1,1,3,3,3-hexafluoro-2-propanol, HOC6H4-
4-X (X ) H, NO2, OH, CN, Cl, Me, OMe), catechol, and Celite
(filter aid) were purchased from J anssen Chimica. The
compounds Ph2PCH2CH2NMe2 (PN),22 [Pd(Me)2(tmeda)],13a
[Pd(Me)2(PCN)] (1),13a and [Pd(Me)(OCH(CF3)2)(tmeda)]11 were
prepared according to the literature. 1H (300.13 MHz), 13C
(75.04 MHz), and 31P (121.47 MHz) NMR spectra were
recorded on a Bruker AC 300 spectrometer at ambient tem-
perature in deuterated solvents (CDCl3, C6D6, CD3COCD3, and
toluene-d8) obtained from ISOTEC Inc. NMR data for the
Hammet correlation have been obtained by using the same
measurement conditions (solvent CD3COCD3, temperature 298
K, and concentration 0.015 M) to minimize errors. Elemental
analyses were carried out by Dornis and Kolbe, Mikroana-
lytisches Laboratorium, Mu¨lheim a.d. Ruhr, Germany.
P r ep a r a tion of [P d (Me)2(P N)] (2). To a solution of [Pd-
(Me)2(tmeda)] (0.94 g, 3.72 mmol) in benzene (20 mL) was
added a solution of PN (1.00 g, 3.88 mmol) in a mixture of
benzene (5 mL) and pentane (40 mL). The resulting yellow
solution was stirred for 3 h, during which time a white
precipitate of the product was formed. The solid was isolated
by decantation, washed with pentane (2 × 5 mL), and dried
in vacuo. The product can be crystallized from slow diffusion
P r ep a r a tion of [P d (Me)(OC6H4-4-OMe)(P N)] (5). To a
solution of [Pd(Me)2(PN)] (2) (0.30 g, 0.76 mmol) in a mixture
of benzene (3 mL) and Et2O (3 mL) was added a solution of
anisole (0.046 g, 0.78 mmol) in benzene (5 mL). After 10 min,
the white precipitate was isolated by decantation, washed with
pentane (3 × 30 mL), and dried in vacuo: yield 0.26 g (69%);
1H NMR (CD3COCD3) δ 7.83-7.76 (m, 4H, aryl), 7.59-7.52
3
(m, 6H, aryl), 6.65 (d, 2H, J H,H ) 9 Hz, o-H PdOAr), 6.55 (d,
2H, 3J H,H ) 9 Hz, m-H PdOAr), 3.61 (s, 3H, OCH3), 2.79-2.72
(m, 2H, CH2), 2.62-2.50 (m, 2H, CH2), 2.61 (s, 6H, NCH3),
0.31 (d, 3H, 3J H,P ) 2.55 Hz, PdCH3); 13C NMR (CD3COCD3) δ
2
169.66 (ipso-C PdOAr), 134.11 (d, J C,P ) 12 Hz, m-C aryl),
131.98 (d, 1J C,P ) 50 Hz, ipso-C aryl), 131.95 (p-C aryl), 129.82
3
(d, J C,P ) 11 Hz, o-C aryl), 129.10 (m-H PdOAr), 120.64 (p-H
PdOAr), 115.31 (o-H PdOAr), 59.25 (NCH2), 56.26 (OCH3),
1
2
48.31 (NCH3), 31.13 (d, J C,P ) 29 Hz, PCH2), -4.23 (d, J C,P
) 6.0 Hz, PdCH3); 31P{1H} NMR (CD3COCD3) δ 48.39. Anal.
Calcd for C24H30NO2PPd: C, 57.43; H, 6.03; N, 2.79. Found:
C, 57.36; H, 6.00; N, 2.73.
P r ep a r a tion of [P d (Me)(OC6H4-4-Me)(P N)] (6). To a
solution of [Pd(Me)2(PN)] (2) (0.162 g, 0.42 mmol) in benzene
(5 mL) was added a solution of p-cresol (0.048 g, 0.44 mmol)
in Et2O (20 mL). After 30 min, the beige precipitate that had
formed was isolated by decantation, washed with pentane (3
1
× 30 mL), and dried in vacuo: yield 0.13 g (65%); H NMR
(CD3COCD3) δ 7.84-7.77 (m, 4H, aryl), 7.59-7.53 (m, 6H,
aryl), 6.71 (d, 2H, 3J H,H ) 8 Hz, o-H PdOAr), 6.63 (d, 2H, 3J H,H
) 8 Hz, m-H PdOAr), 2.78-2.70 (m, 2H, CH2), 2.64-2.49 (m,
2H, CH2), 2.61 (s, 6H, NCH3), 2.10 (s, 3H, OArCH3), 0.32 (d,
1
of pentane into a solution of benzene: yield 1.23 g (84%); H
NMR (CD3COCD3) δ 7.75-7.21 (m, 10H, aryl), 2.63-2.40 (m,
3
4H, CH2CH2), 2.52 (s, 6H, N(CH3)2), 0.25 (d, 3H, J H,P ) 7.8
3
3
3H, J H,P ) 2.55 Hz, PdCH3); 13C NMR (CD3COCD3) δ 168.70
Hz, PdCH3), -0.38 (d, 3H, J H,P ) 7.2 Hz, PdCH3). Anal.
(ipso-C PdOAr), 134.12 (d, 2J C,P ) 12 Hz, m-C aryl), 131.94 (d,
Calcd for C18H20NOPPd‚0.5C6H6: C, 58.27; H, 6.75; N, 3.24.
Found: C, 57.95; H, 6.53; N, 3.15.
3
1J C,P ) 50 Hz, ipso-C aryl), 131.92 (p-C aryl), 129.86 (d, J C,P
) 11 Hz, o-C aryl), 129.82 (m-H PdOAr), 120.80 (o-H PdOAr),
P r ep a r a tion of [P d (Me)(OCH(CF 3)2)(P N)] (3). To a
solution of [Pd(Me)2(PN)] (2) (0.81 g, 2.1 mmol) in benzene (20
mL) was added 1,1,1,3,3,3-hexafluoro-2-propanol (216 µL, 2.1
mmol). After 2 h the yellow solution was reduced in vacuo to
half its volume. The addition of pentane (25 mL) afforded a
white precipitate, which was isolated by decantation, washed
with pentane (4 × 5 mL), and dried in vacuo. The product
can be recrystallized from toluene, yielding colorless crystals:
yield 0.90 g (80%); 1H NMR (CD3COCD3) δ 7.79-7.63 (m, 4H,
2
120.04 (p-H PdOAr), 59.15 (d, J C,P ) 5 Hz, NCH2), 48.13
(NCH3), 31.14 (d, 1J C,P ) 29 Hz, PCH2), 20.60 (OArCH3), -4.64
(d, 2J C,P ) 6.8 Hz, PdCH3); 31P{1H} NMR (CD3COCD3) δ 48.56.
Anal. Calcd for C24H30NOPPd: C, 59.33; H, 6.22; N, 2.88.
Found: C, 59.21; H, 6.28; N, 2.93.
P r ep a r a tion of [P d (Me)(OC6H4-4-Cl)(P N)] (7). To a
solution of [Pd(Me)2(PN)] (2) (0.151 g, 0.38 mmol) in benzene
(5 mL) was added a solution of p-chlorophenol (0.049 g, 0.38
mmol) in Et2O (10 mL). After 30 min, the white precipitate
that had formed was isolated by decantation, washed with
Et2O (5 mL) and pentane (3 × 30 mL), and dried in vacuo:
yield 0.17 g (88%); 1H NMR (CD3COCD3) δ 7.84-7.77 (m, 4H,
3
aryl), 7.60-7.48 (m, 6H, aryl), 4.48 (septet, 1H, J H,F ) 6.5
Hz, OCH), 2.75-2.50 (m, 4H, CH2CH2), 2.60 (s, 6H, NCH3),
3
0.15 (d, 3H, J H,P ) 1.2 Hz, PdCH3); 13C NMR (CD3COCD3) δ
2
134.09 (d, J C,P ) 12 Hz, m-C aryl), 132.02 (p-C aryl), 131.42
1
3
3
(d, J C,P ) 50 Hz, ipso-C aryl), 129.80 (d, J C,P ) 11 Hz, o-C
aryl), 7.60-7.55 (m, 6H, aryl), 6.85 (d, 2H, J H,H ) 8 Hz, o-H
1
2
3
aryl), 125.62 (q, J C,F ) 286 Hz), 74.98 (septet, J C,F ) 29 Hz,
PdOAr), 6.67 (d, 2H, J H,H ) 8 Hz, m-H PdOAr), 2.79-2.73
2
OCH), 59.34 (d, J C,P ) 5 Hz, NCH2), 47.48 (NCH3), 31.35 (d,
(m, 2H, CH2), 2.66-2.53 (m, 2H, CH2), 2.61 (s, 6H, NCH3),
1J C,P ) 12 Hz, PCH2), -3.24 (d, 2J C,P ) 7.5 Hz, PdCH3). Anal.
Calcd for C20H24F6NOPPd: C, 44.01; H, 4.43; N, 2.57. Found:
C, 44.16; H, 4.42; N, 2.67.
0.30 (d, 3H, 3J H,P ) 2.39 Hz, PdCH3); 13C NMR (CD3COCD3) δ
2
167.12 (ipso-C PdOAr), 134.21 (d, J C,P ) 12 Hz, m-C aryl),
132.02 (p-C aryl), 131.55 (d, 1J C,P ) 50 Hz, ipso-C aryl), 129.83
3
P r ep a r a tion of [P d (Me)(OC6H5)(P N)] (4). To a solution
of [Pd(Me)2(PN)] (2) (0.70 g, 1.8 mmol) in benzene (10 mL) ws
added a solution of phenol (0.17 g, 1.8 mmol) in a mixture of
benzene (5 mL) and pentane (20 mL). After 1 h, the white
precipitate that had formed was isolated by decantation,
washed with pentane (3 × 30 mL), and dried in vacuo: yield
0.76 g (91%); 1H NMR (CD3COCD3) δ 7.85-7.76 (m, 4H, aryl),
7.62-7.52 (m, 6H, aryl), 6.89 (t, 2H, 3J H,H ) 8 Hz, o-H PdOAr),
(d, J C,P ) 11 Hz, o-C aryl), 128.88 (m-H PdOAr), 122.11 (o-H
2
PdOAr), 119.80 (p-H PdOAr), 59.13 (d, J C,P ) 5 Hz, NCH2),
1
2
48.13 (NCH3), 31.15 (d, J C,P ) 29 Hz, PCH2), -4.82 (d, J C,P
) 6.7 Hz, PdCH3); 31P{1H} NMR (CD3COCD3) δ 49.13. Anal.
Calcd for C23H27ClNOPPd: C, 54.56; H, 5.38; N, 2.77. Found:
C, 54.41; H, 5.29; N, 2.77.
P r ep a r a tion of [P d (Me)(OC6H4-4-CN)(P N)] (8). To a
solution of [Pd(Me)2(PN)] (2) (0.118 g, 0.30 mmol) in Et2O (5
mL) was added a solution of p-cyanophenol (0.036 g, 0.30
mmol) in a mixture of Et2O (5 mL) and benzene (5 mL). After
30 min, pentane (15 mL) was added and an orange precipitate
formed that was isolated by decantation, washed with pentane
(2 × 10 mL), and dried in vacuo: yield 0.13 g (87%); 1H NMR
(CD3COCD3) δ 7.85-7.78 (m, 4H, aryl), 7.62-7.55 (m, 6H,
aryl), 7.24 (d, 2H, 3J H,H ) 8 Hz, o-H PdOAr), 6.77 (d, 2H, 3J H,H
) 8 Hz, m-H PdOAr), 2.85-2.78 (m, 2H, CH2), 2.72-2.63 (m,
3
3
6.72 (d, 2H, J H,H ) 8 Hz, m-H PdOAr), 6.23 (t, 1H, J H,H ) 8
Hz, p-H PdOAr), 2.80-2.72 (m, 2H, CH2), 2.63-2.50 (m, 2H,
CH2), 2.61 (s, 6H, NCH3), 0.33 (d, 3H, 3J H,P ) 2.48 Hz, PdCH3);
13C NMR (CD3COCD3) δ 134.12 (d, J C,P ) 12 Hz, m-C aryl),
2
131.91 (p-C aryl), 131.70 (d, 1J C,P ) 50 Hz, ipso-C aryl), 129.80
3
(d, J C,P ) 10 Hz, o-C aryl), 129.22 (m-H PdOAr), 121.14 (o-H
PdOAr), 112.21 (p-H PdOAr), 59.15 (d, J C,P ) 5 Hz, NCH2),
48.14 (NCH3), 31.15 (d, J C,P ) 29 Hz, PCH2), -4.86 (d, J C,P
) 6.6 Hz, PdCH3); 31P{1H} NMR (CD3COCD3) δ 48.68. Anal.
Calcd for C23H28NOPPd: C, 58.54; H, 5.98; N, 2.97. Found:
C, 58.52; H, 5.93; N, 2.91.
2
1
2
3
2H, CH2), 2.60 (s, 6H, NCH3), 0.29 (d, 3H, J H,P ) 2.17 Hz,
PdCH3); 13C NMR (CD3COCD3) δ 175.25 (ipso-C PdOAr),
2
134.17 (d, J C,P ) 12 Hz, m-C aryl), 133.90 (m-H PdOAr),
132.20 (p-C aryl), 131.06 (d, 1J C,P ) 50 Hz, ipso-C aryl), 129.93
3
(22) Smith, R. T.; Baird, M. C. Inorg. Chim. Acta 1982, 62, 135.
(d, J C,P ) 11 Hz, o-C aryl), 122.31 (p-H PdOAr), 121.90 (o-H

P,N-Ligated Methylpalladium(II) Alkoxide Complexes
Organometallics, Vol. 15, No. 5, 1996 1411
Ta ble 4. Cr ysta llogr a p h ic Da ta for 12 a n d 14
12
14
Crystal Data
formula
molecular weight
crystal system
space group
a (Å)
C28H30NOPPd‚CH2Cl2
C28H30NOPPd‚C6H6O
628.06
triclinic
618.88
triclinic
P1h (No. 2)
8.2903(9)
11.5330(13)
16.0124(15)
102.641(8)
90.736(8)
105.567(9)
1434.9(3)
1.432
P1h (No. 2)
10.903(3)
11.763(2)
12.598(2)
76.806(11)
83.366(15)
71.733(15)
1492.1(6)
1.398
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
D
Z
calc (g cm-3
)
2
2
F(000)
632
648
µ (cm-1
)
9.0 (Mo KR)
0.7 × 0.5 × 0.2
58.8 (Cu KR)
0.5 × 0.5 × 0.2
crystal size (mm)
Data Collection
T (K)
298
295
θ
min, θmax (deg)
1.31, 25.48
0.71073 (Mo KR, Zr-filtered)
ω/2θ
3.61, 74.99
1.54184 (Cu KR, Ni-filtered)
ω/2θ
0.71 + 0.14 tan θ
4.18, 6.00
101
wavelength (Å)
scan type
∆ω (deg)
0.94 + 0.35 tan θ
hor., ver. aperture (mm)
X-ray exposure time
linear decay (%)
reference reflections
data set
3.17, 5.00
80
81
2h14h,2h23,142h
-9:9,0:13,-19:18
5518
10
2h32,1h24h,052
-13:13,-14:14,-15:15
12641
total data
total unique data
DIFABS corr range
5236 (Rint ) 0.045)
0.759, 1.191
6125 (Rint ) 0.037)
0.686, 1.951
Refinement
319
0.062 [3467 Fo > 4σ(Fo)]
0.167
no. of refined params
final Ra
359
0.039 [5446 Fo > 4σ(Fo)]
0.114
final wR2b
goodness of fit
weighting schemec
(∆/σ)av, (∆/σ)max
min and max
1.04
1.11
[σ2(F2) + (0.1026P)2]-1
0.000, -0.001
[σ2(F2) + (0.0466P)2 + 2.39P]-1
0.000, -0.004
residual density (e Å-3
)
-0.86, 0.68
-1.30, 1.09 (near Pd)
2
2
2
R ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) [∑[w(Fo - Fc)2]/∑[w(Fo)2]]1/2
.
c P ) (max(Fo2,0) + 2F2c)/3.
a
b
2
PdOAr), 59.08 (d, J C,P ) 5 Hz, NCH2), 48.24 (NCH3), 31.20
(7 mL) was added 1,1,1,3,3,3-hexafluoro-2-propanol (21 µL,
0.021 mmol). The solution turned yellow and a precipitate
formed. After 1 h the suspension was evaporated to dryness
in vacuo, and the residue was washed with pentane (3 × 10
1
2
(d, J C,P ) 29 Hz, PCH2), -5.05 (d, J C,P ) 6.1 Hz, PdCH3);
31P{1H} NMR (CD3COCD3)
49.71. Anal. Calcd for
24H27N2OPPd: C, 58.01; H, 5.48; N, 5.64. Found: C, 58.09;
H, 5.53; N, 5.71.
δ
C
1
mL) and dried in vacuo: yield 0.110 g (93%); H NMR (C6D6)
3
δ 7.41-6.69 (m, 14H, aryl), 5.05 (septet, 1H, J H,F ) 6.5 Hz,
P r ep a r a tion of [P d (Me)(OC6H4-4-NO2)(P N)] (9). To a
solution of [Pd(Me)2(PN)] (2) (0.271 g, 0.69 mmol) in benzene
(5 mL) was added a solution of p-nitrophenol (0.097 g, 0.70
mmol) in a mixture of Et2O (10 mL) and pentane (5 mL). After
15 min, a yellow precipitate formed that was isolated by
decantation, washed with pentane (2 × 20 mL), and dried in
vacuo: yield 0.28 g (85%); 1H NMR (CD3COCD3) δ 7.94 (d, 2H,
3J H,H ) 8 Hz, o-H PdOAr), 7.93-7.81 (m, 4H, aryl), 7.62-7.55
OCH), 2.84 (br m, 2H, CH2), 2.42 (br m, 6H, NCH3), 0.61 (d,
3
3H, J H,P ) 2.2 Hz, PdCH3). Anal. Calcd for C25H26F6-
NOPPd: C, 49.40; H, 4.31; N, 2.30. Found: C, 48.66; H, 4.46;
N, 2.47.
P r ep a r a tion of [P d (Me)(OC6H5)(P CN)] (12). To a solu-
tion of [Pd(Me)2(PCN)] (1) (0.63 g, 0.14 mmol) in benzene (10
mL) was added a solution of phenol (0.13 g, 0.14 mmol) in a
mixture of benzene (5 mL) and Et2O (20 mL). A white
precipitate formed, which was isolated after 1 h by decantation,
washed with Et2O (25 mL), and dried in vacuo. The product
can be crystallized by slow diffusion of pentane into a CH2Cl2
solution, affording yellow crystals suitable for X-ray diffrac-
tion: yield 0.61 g (81%); 1H NMR (C6D6) δ 7.87-6.79 (m, 18H,
3
(m, 6H, aryl), 6.72 (d, 2H, J H,H ) 8 Hz, m-H PdOAr), 2.85-
3
2.60 (m, 4H, CH2CH2), 2.60 (s, 6H, NCH3), 0.30 (d, 3H, J H,P
) 2.01 Hz, PdCH3); 31P{1H} NMR (CD3COCD3) δ 50.15. Anal.
Calcd for C23H27N2O3PPd: C, 53.45; H, 5.27; N, 5.42. Found:
C, 53.34; N, 5.36; N, 5.48.
P r ep a r a tion of [P d (Me)(OC6H4-4-OH)(P N)] (10). To a
solution of [Pd(Me)2(PN)] (2) (0.186 g, 0.52 mmol) in Et2O (5
mL) was added a solution of hydroquinone (0.052 g, 0.52 mmol)
in a mixture of Et2O (5 mL) and benzene (2 mL). After the
solution was warmed to 35 °C for 15 min, a white precipitate
formed that was isolated by decantation, washed with Et2O
3
aryl), 6.57 (t, 1H, J H,H ) 7 Hz, p-H PdOPh), 2.86 (br m, 2H,
3
CH2), 2.37 (br s, 6H, NCH3), 0.97 (d, 3H, J H,P ) 3.3 Hz,
PdCH3); 13C NMR (CDCl3) δ 141.81, 134.39, 134.23, 132.83,
132.71, 131.08, 130.94, 129.23, 129.15, 128.89, 128.45, 127.68,
2
120.37, 112.73, 66.46 (d, J C,P ) 9.4 Hz, CH2), 48.25 (NCH3),
2
1
2.13 (d, J C,P ) 5.5 Hz, PdCH3). Anal. Calcd for C28H30
-
(2 × 5 mL), and dried in vacuo: yield 0.19 g (81%); H NMR
NOPPd: C, 62.99; H, 5.66; N, 2.62. Found: C, 62.78; H, 5.74;
N, 2.66.
P r ep a r a tion of [P d (Me)(OC6H4-4-CN)(P CN)] (13). To
a solution of [Pd(Me)2(PCN)] (1) (0.0965 g, 0.210 mmol) in Et2O
(5 mL) was added a solution of p-cyanophenol (0.0252 g, 0.210
(CD3COCD3) δ 8.02-7.10 (m, 14H, aryl), 2.69-2.48 (m, 4H,
3
CH2CH2), 2.63 (s, 6H, NCH3), 0.81 (d, 3H, J H,P ) 2.71 Hz,
PdCH3).
P r ep a r a tion of [P d (Me)(OCH(CF 3)2)(P CN)] (11). To a
solution of [Pd(Me)2(PCN)] (1) (0.089 g, 0.020 mmol) in benzene

1412 Organometallics, Vol. 15, No. 5, 1996
Kapteijn et al.
Ta ble 6. F in a l Coor d in a tes a n d Equ iva len t
Ta ble 5. F in a l Coor d in a tes a n d Equ iva len t
Isotr op ic Th er m a l P a r a m eter s of
th e Non -Hyd r ogen Atom s for 12
(esd ’s in P a r en th eses)a
Isotr op ic Th er m a l P r op er ties of th e Non -Hyd r ogen
Atom s for 14 (esd ’s in P a r en th eses)a
atom
x
y
z
Ueq (Å2)a
atom
x
y
z
Ueq (Å2)a
Pd(1)
P(1)
O(1)
N(1)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10) 0.9341(3)
C(11) 1.0211(4)
C(12) 1.0652(5)
C(13) 1.0234(5)
C(14) 0.9398(5)
C(15) 0.8953(4)
C(16) 0.7803(4)
C(17) 0.6664(4)
C(18) 0.5943(4)
C(19) 0.6320(5)
C(20) 0.7437(5)
C(21) 0.8189(5)
C(22) 1.1605(4)
C(23) 1.2474(3)
C(24) 1.2421(4)
C(25) 1.3372(5)
C(26) 1.4414(5)
C(27) 1.4501(4)
C(28) 1.3554(4)
1.01685(2)
0.87715(8)
1.1554(2)
0.8646(3)
0.8970(4)
0.8745(4)
0.7291(4)
0.7031(3)
0.6164(4)
0.5868(4)
0.6436(5)
0.7294(4)
0.7595(3)
0.20659(2)
0.28440(8)
0.1299(2)
0.1735(3)
0.0406(4)
0.2317(4)
0.2224(4)
0.1732(3)
0.1051(4)
0.0593(4)
0.0815(4)
0.1510(4)
0.1981(3)
0.2811(3)
0.1722(4)
0.1598(5)
0.2558(5)
0.3629(5)
0.3768(4)
0.4406(3)
0.4969(4)
0.6134(4)
0.6747(4)
0.6201(4)
0.5038(4)
0.2452(5)
0.0260(3)
-0.0580(4)
-0.1686(4)
-0.1991(4)
-0.1179(4)
-0.0069(4)
0.21564(2) 0.0343(1)
0.08664(7) 0.0345(2)
Pd(1) 0.82149(5)
0.15967(4)
0.25480(3)
0.0494(2)
0.3354(2)
0.3417(2)
0.3824(3)
0.4320(3)
0.3082(3)
0.2154(3)
0.2332(4)
0.1514(4)
0.0482(4)
0.0276(4)
0.1096(3)
-0.0545(3)
-0.0741(3)
-0.1793(4)
-0.2650(4)
-0.2465(4)
-0.1404(3)
0.0908(3)
0.0360(4)
0.0438(5)
0.1095(4)
0.1639(4)
0.1544(3)
0.1108(4)
0.3339(3)
0.2738(3)
0.2796(4)
0.3433(4)
0.4029(4)
0.3985(3)
0.0406(8)
P(1)
O(1)
N(1)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
0.9740(2)
0.6718(6)
1.0218(6)
0.9612(9)
1.0479(9)
1.1877(7)
1.1848(7)
1.2751(8)
1.2828(9)
1.1963(9)
1.1006(7)
1.0960(6)
0.34281(13) 0.24525(10) 0.0467(5)
0.0384(12)
0.0479(12)
0.0521(14)
0.0430(12)
0.0402(12)
0.0526(14)
0.0586(16)
0.0576(16)
0.0464(12)
0.0380(12)
0.0374(12)
0.0494(12)
0.0597(16)
0.0641(16)
0.0634(16)
0.0503(12)
0.0392(12)
0.0513(14)
0.0622(16)
0.0612(16)
0.0595(16)
0.0506(14)
0.0584(14)
0.0366(12)
0.0488(12)
0.0572(16)
0.0594(16)
0.0521(16)
0.0444(12)
-0.0139(4)
0.0734(4)
-0.0163(6)
0.0063(7)
0.1579(6)
0.2366(5)
0.2238(6)
0.2982(7)
0.3857(7)
0.3985(6)
0.3273(5)
0.4586(5)
0.4232(6)
0.5066(8)
0.6257(8)
0.6600(6)
0.5749(5)
0.4224(5)
0.5061(6)
0.5754(7)
0.5581(8)
0.4739(8)
0.4045(6)
0.2276(6)
-0.0766(5)
-0.0501(6)
-0.1237(7)
0.2635(3)
0.2102(3)
0.1270(5)
0.2753(6)
0.2010(4)
0.1377(4)
0.0651(5)
0.0086(5)
0.0211(4)
0.0933(4)
0.1508(4)
0.2336(4)
0.1751(5)
0.1644(5)
0.2153(6)
0.2747(5)
0.2840(4)
0.3317(4)
0.3207(4)
0.3896(5)
0.4708(5)
0.4820(5)
0.4138(4)
0.3053(5)
0.2095(5)
0.1304(5)
0.0718(5)
0.0942(7)
0.1713(8)
0.2303(6)
0.0683(16)
0.0588(19)
0.084(3)
0.086(3)
0.063(2)
0.0545(19)
0.073(3)
0.079(3)
0.077(3)
0.059(2)
0.0485(17)
0.050(2)
0.068(3)
0.084(3)
0.087(4)
0.079(3)
0.064(2)
0.053(2)
0.068(2)
0.082(3)
0.083(3)
0.080(3)
0.062(2)
0.075(3)
0.058(2)
0.071(3)
0.086(3)
0.095(4)
0.098(4)
0.079(3)
C(10) 0.8676(6)
C(11) 0.7287(8)
C(12) 0.6426(9)
C(13) 0.6924(11)
C(14) 0.8264(9)
C(15) 0.9115(8)
C(16) 1.1323(7)
C(17) 1.2798(8)
C(18) 1.3920(8)
C(19) 1.3571(9)
C(20) 1.2162(10)
C(21) 1.1018(8)
C(22) 0.6344(8)
C(23) 0.5406(7)
C(24) 0.5160(8)
C(25) 0.3815(9)
C(26) 0.2712(10) -0.2200(7)
C(27) 0.2893(10) -0.2443(7)
C(28) 0.4208(8)
-0.1711(6)
O(2)
0.1742(4)
0.2704(4)
0.3377(4)
0.4191(5)
0.4907(5)
0.4825(5)
0.4021(5)
0.3305(4)
0.4635(3)
0.4232(4)
0.4827(4)
0.4432(6)
0.3465(6)
0.2881(5)
0.3253(4)
0.0710(14)
0.0528(14)
0.0676(17)
0.081(2)
0.077(2)
0.0652(17)
0.0550(14)
C(29) 0.2560(4)
C(30) 0.2683(5)
C(31) 0.3497(6)
C(32) 0.4193(5)
C(33) 0.4070(5)
C(34) 0.3261(4)
Cl(1)
Cl(2)
C(29) 0.745(2)
0.8111(6)
0.7092(6)
0.1456(3)
-0.1163(3)
0.0169(11)
0.5334(3)
0.4921(3)
0.4625(7)
0.203(2)
0.199(2)
0.189(8)
a
Ueq is one-third of the trace of the orthogonalized U tensor.
mmol) in Et2O (5 mL). After 1 h, the white solid that had
precipitated was isolated by decantation, washed with pentane
(3 × 5 mL), and dried in vacuo: yield 0.093 g (79%); 1H NMR
(CDCl3) δ 7.52-7.21 (m, 14H, aryl), 7.00-6.84 (m, 4H, aryl),
3.37 (br m, 2H, CH2), 2.47 (br m, 6H, NCH3), 0.39 (d, 3H, 3J H,P
) 2.8 Hz, PdCH3). Anal. Calcd for C29H29N2OPPd: C, 62.32;
H, 5.23; N, 5.01. Found: C, 62.38; H, 5.23; N, 5.09.
a
Ueq is one-third of the trace of the orthogonalized U tensor.
P r ep a r a tion of [P d (Me)(CtCP h )(P N)] (16). Pheny-
lacetylene (1.0 mL, 9.2 mmol) was added to a solution of [Pd-
(Me)(OCH(CF3)2)(PN)] (2) (0.24 g, 0.44 mmol) in diethyl ether
(15 mL). After 15 min, the white precipitate that had formed
was isolated, washed with pentane (2 × 10 mL), and dried in
vacuo: yield 0.18 g (86%); 1H NMR (CD3COCD3) δ 7.82-7.42
P r ep a r a tion of [P d (Me)(OC6H5)(P CN)]‚HOC6H5 (14).
To a solution of [Pd(Me)2(PCN)] (1) (0.182 g, 0.40 mmol) in
Et2O (15 mL) was added phenol (0.075 g, 0.80 mmol). After
10 min, the white precipitate that had formed was isolated by
decantation, washed with pentane (2 × 10 mL), and dried in
vacuo. The product can be crystallized by slow diffusion of
pentane into a CH2Cl2 solution, affording plate-shaped color-
less crystals suitable for X-ray diffraction: yield 0.152 g (62%);
1H NMR (C6D6) δ 9.30 (br s, 1H, OH), 7.43-6.78 (m, 19H, aryl),
3
(m, 10H, ArH), 7.28 (d, 2H, J H,H ) 7 Hz, o-ArH), 7.17 (t, 2H,
3J H,H ) 7 Hz, m-ArH), 7.06 (t, 1H, J H,H ) 7 Hz, p-ArH), 2.81
3
3
(s, 6H, NCH3), 2.70-2.45 (m, 4H, CH2CH2), 0.51 (d, 3H, J H,P
) 7.2 Hz, PdCH3). Anal. Calcd for C25H28NPPd: C, 62.57; H,
5.88; N, 2.92. Found: C, 62.55; H, 5.95; N, 2.99.
P r ep a r a tion of [P d (Me)(CtCP h )(tm ed a )] (17). Pheny-
lacetylene (0.25 mL, 2.3 mmol) was added to a solution of [Pd-
(Me)(OCH(CF3)2)(tmeda)] (0.85 g, 2.1 mmol) in Et2O (10 mL)
at 0 °C. After 15 min a white precipitate formed, and this
was isolated by decantation, washed with pentane (2 × 5 mL),
3
6.53 (t, 1H, J H,H ) 7 Hz, p-H PdOPh), 2.84 (s, 4H, CH2), 2.32
3
(s, 6H, NCH3), 0.98 (d, 3H, J H,P ) 3.1 Hz, PdCH3); 13C NMR
(CDCl3) δ 66.58 (d, 2J C,P ) 11 Hz, CH2), 48.42 (NCH3), 2.89 (d,
2J C,P ) 5 Hz, PdCH3). Anal. Calcd for C34H36NO2PPd: C,
65.02; H, 5.78; N, 2.23. Found: C, 64.88; H, 5.73; N, 2.29.
1
and dried in vacuo: yield 0.52 g (74%); H NMR (CDCl3, 273
3
K) δ 7.38 (d, 1H, J H,H ) 7 Hz, o-Ph), 7.15 (m, 2H, p-Ph), 7.07
(m, 1H, m-Ph), 2.71-2.45 (m, 4H, CH2CH2), 2.66 (s, 6H,
NCH3), 2.49 (s, 6H, NCH3), 0.31 (s, 3H, PdCH3); 13C NMR
(CDCl3, 273 K) δ 131.45 (ArC), 128.40 (Cipso Ar), 127.74 (ArC),
124.78 (ArC), 105.83 (CtC), 103.64 (CtC), 61.50 (CH2), 58.78
(CH2), 49.32 (NCH3), 48.78 (NCH3), -9.33 (PdCH3). Anal.
Calcd for C15H24N2Pd: C, 53.18; H, 7.14; N, 8.27. Found: C,
51.30; H, 6.85; N, 8.13.
P r ep a r a tion of [P d (Me)(SC6H5)(P CN)] (15). To a solu-
tion of [Pd(Me)(OCH(CF3)2)(PCN)] (10) (0.10 g, 0.20 mmol) in
benzene (15 mL) was added benzenethioacetate (0.030 g, 0.20
mmol). After 2 h, the orange solution was evaporated to
dryness in vacuo and the residue was washed with pentane
(2 × 10 mL) to afford a red solid, which was dried in vacuo:
yield 0.08 g (70%); 1H NMR (CD3COCD3) δ 7.90-7.30 (m, 12H,
aryl), 7.10-6.70 (m, 3H, aryl), 2.82-2.58 (m, 4H, CH2CH2),
Th er m olysis of Alk yn yl Com p lexes 16 a n d 17.
A
solution of 16 or 17 in acetone was heated at 50 °C for 2 h,
and the solution was filtered through Celite to remove Pd(0).
GLC analysis of the filtrate (diphenylmethane as internal
standard) showed the formation of methylphenylacetylene. In
3
2.60 (s, 6H, NCH3), 0.30 (d, 3H, J H,P ) 3 Hz, PdCH3). Anal.
Calcd for C34H36NPPdS: C, 56.62; H, 5.78; N, 2.87. Found:
C, 57.09; H, 5.73; N, 3.11.

P,N-Ligated Methylpalladium(II) Alkoxide Complexes
Organometallics, Vol. 15, No. 5, 1996 1413
a similar experiment, CO was bubbled for 10 min through a
solution of 16 and 17 followed by removal of Pd(0) by filtration.
GLC analysis of the filtrate (diphenylmethane as internal
standard) showed the formation of methylphenylacetylene and
MeCOCtCPh.
displaying an unequal background were omitted during the
final refinements of complex 14. Hydrogen atoms were
included in the refinement on calculated positions riding on
their carrier atoms, except for phenolic hydroxyl hydrogen
(compound 14), which was located on a difference Fourier map
and subsequently included in the refinement. The methyl
groups of both complexes were refined as rigid groups, allowing
for rotation around the N-C bonds. Non-hydrogen atoms were
refined with anisotropic thermal parameters. The hydrogen
atoms were refined with a fixed isotropic thermal parameter
related to the value of the equivalent isotropic thermal
parameter of their carrier atoms by a factor amounting to 1.5
for the hydroxyl and methyl hydrogen atoms and 1.2 for the
other hydrogen atoms. Final positional parameters are listed
in Tables 5 and 6 for 12 and 14, respectively. Neutral atom
scattering factors and anomalous dispersion corrections were
taken from the International Tables for Crystallography.28
Geometrical calculations and illustrations were preformed with
PLATON;29 all calculations were performed on a DECstation
5000 cluster.
Rea ction of 2 a n d HOCH(CF 3)2 [in Situ P r ep a r a tion
of t h e Ad d u ct [P d (Me)(OCH (CF 3)2)(P N)]‚H OCH (CF 3)2
(18)]. A solution of 2 in toluene-d8 (0.50 mL) was transferred
to an NMR tube containing 1 equiv of HOCH(CF3)2. 1H NMR
showed the quantitative formation of the alcohol adduct 18.
Attempts to isolate this OsH‚‚‚O hydrogen-bonded adduct by
crystallization in toluene/pentane at -20 °C failed and the
starting materials were recovered.
X-r a y Str u ctu r e Deter m in a tion of 12 a n d 14. Crystals
of 12 (yellow) and 14 (colorless) suitable for X-ray diffraction
were glued to the tip of a Lindemann glass capillary and
transferred to an Enraf-Nonius CAD4-F diffractometer. Ac-
curate unit cell parameters and an orientation matrix were
determined by least-squares refinement of the setting angles
of 25 well-centered reflections (SET4)23 in the ranges 12.4° <
θ < 19.3° and 16.5° < θ < 24.7° for 12 and 14, respectively.
The unit cell parameters were checked for the presence of
higher lattice symmetry.24 Crystal data and details on data
collection and refinement are presented in Table 4. Data were
correlated for Lp effects and for the observed linear decay of
the reference reflections. An empirical absorption extinction
correction was applied (DIFABS)25 for both complexes. The
structures were solved by automated Patterson methods and
subsequent difference Fourier techniques (DIRDIF-92).26 Both
complexes were refined on F2 by full-matrix least-squares
techniques (SHELXL-93);27 no observance criterion was ap-
plied during refinement. Thirty-one deviating reflections
Ack n ow led gm en t. Shell Research B.V. (G.M.K.) is
gratefully thanked for financial support. The work was
supported in part (A.L.S.) by the Netherlands Founda-
tion for Chemical Research (SON), with financial aid
from the Netherlands Organization for Scientific Re-
search (NWO).
Su p p or tin g In for m a tion Ava ila ble: Further details of
the structure determinations, including atomic coordinates,
bond lengths and angles, and thermal parameters for 12 and
14 (16 pages). Ordering information is given on any current
masthead page.
(23) de Boer, J . L.; Duisenberg, A. J . M. Acta Crystallogr. 1984, A40,
410.
OM950661I
(24) Spek, A. L. J . Appl. Crystallogr. 1988, 21, 578.
(25) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158.
(26) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garc´ıa-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF program system; Technical report of the Crystallography
Laboratory: University of Nijmegen: Nijmegen, The Netherlands,
1992.
(27) Sheldrick, G. M. SHELXL-93, Program for crystal structure
refinement; University of Go¨ttingen: Germany, 1993.
(28) Wilson, A. J . C., Ed.; International Tables for Crystallography;
Kluwer Academic Publishers: Dordrecht, The Netherlands, 1992;
Volume C.
(29) Spek, A. L. Acta Crystallogr. 1990, A46, C34.