Synthesis of 1,2-dihydroquinazolinium-4-yl palladium complexes through a cyclization reaction

Article abstract of DOI:10.1021/om900616v

The reaction of trans-[PdI{C(=NXy)C₆H₄NH ₂-2}(CNXy)₂] (1, Xy = C₆H₃Me ₂-2,6) with HO₃SCF₃ (HOTf) and RC(O)R′ affords 1,2-dihydro-3-xylylquinazolinium-4-yl complexes trans[PdI{C=N(Xy)C(R) (R′)NHC₆H₄-2}(CNXy)₂]OTf (R = Me, R′ = Me (2a), Ph (2b), CH₂C(O)Me (2c), H (2d), R = H, R′ = H (2e), CH=CH₂ (2f), Ph (2g), C₆H₄Me-4 (To) (2h), (Fe(C₅H₄)(C₅H₅)I (Fc) (2i)). In the absence of a carbonyl compound, the reaction of 1 with HOTf yields complex SP-4-4-[PdI{C,N-C(=NHXy)C₆H₄NH₂-2}CNXy] OTf (3), which reacts with PPh₃ to give SP-4-3-[PdI{C(=NHXy)C ₆H₄NH₂-2}(CNXy)(PPh₃)]OTf (4). In turn, 4 reacts with RC(O)R′ to give complexes SP-4-5-[PdI{C=N(Xy)C(R) (R′)NHC₆H₄-2}(CNXy)(PPh₃)]OTf (R - R′ = Me (2′a), R = H, R′ = CH(Me)(Ph) (2′b), To (2′c)). A possible intermediate in the cyclization process, trans[PdI{C(=NXy)C₆H₄N=CHTo-2}(CNXy)₂] (6), has been prepared by reacting IC₆H₄N= CHTo-2, [Pd ₂(dba)₃]·dba ("Pd(dba)₂") (dba = dibenzylideneacetone) with N∧N (to give [PdI(C₆H ₄N=CHTo-2)(N∧N)] (N∧N∧ = 2,2′-bipyridine (bpy, 5a), 4,4′-di-rerr-butyl-2,2′-bipyridine (tbbp, Sb)) and XyNC. The crystal structures of complexes 2i, 2′a, 3, and 6 have been determined, and the electrochemical behavior of 2i has been studied.

Full text of DOI:10.1021/om900616v

Organometallics 2009, 28, 5915–5924 5915
DOI: 10.1021/om900616v
Synthesis of 1,2-Dihydroquinazolinium-4-yl Palladium Complexes
through a Cyclization Reaction
ꢀ
Jose Vicente,* Marıa Teresa Chicote, and Antonio J. Martınez-Martınez
´ ´ ´
Grupo de Quımica Organometalica, Departamento de Quımica Inorganica, Facultad de Quımica,
ꢀ
Universidad de Murcia, E-30071 Murcia, Spain
ꢀ
Delia Bautista*,†
SAI, Universidad de Murcia, E-30071 Murcia, Spain
Received July 14, 2009
The reaction of trans-[PdI{C(dNXy)C6H4NH2-2}(CNXy)2] (1, Xy=C6H3Me2-2,6) with HO3-
SCF3 (HOTf) and RC(O)R0 affords 1,2-dihydro-3-xylylquinazolinium-4-yl complexes trans-
[PdI{CdN(Xy)C(R)(R0)NHC6H4-2}(CNXy)2]OTf (R=Me, R0 =Me (2a), Ph (2b), CH2C(O)Me
(2c), H (2d), R = H, R0 = H (2e), CHdCH2 (2f), Ph (2g), C6H4Me-4 (To) (2h), {Fe(C5-
H4)(C5H5)} (Fc) (2i)). In the absence of a carbonyl compound, the reaction of 1 with HOTf yields
complex SP-4-4-[PdI{C,N-C(dNHXy)C6H4NH2-2}CNXy]OTf (3), which reacts with PPh3 to give
SP-4-3-[PdI{C(dNHXy)C6H4NH2-2}(CNXy)(PPh3)]OTf (4). In turn, 4 reacts with RC(O)R0 to give
complexes SP-4-3-[PdI{CdN(Xy)C(R)(R0)NHC6H4-2}(CNXy)(PPh3)]OTf (R = R0 = Me (20a),
R=H, R0 =CH(Me)(Ph) (20b), To (20c)). A possible intermediate in the cyclization process, trans-
[PdI{C(dNXy)C6H4NdCHTo-2}(CNXy)2] (6), has been prepared by reacting IC6H4Nd
CHTo-2, [Pd2(dba)3] dba (“Pd(dba)2”) (dba=dibenzylideneacetone) with N^N (to give [PdI(C6H4-
3
NdCHTo-2)(N^N)] (N^N^=2,20-bipyridine (bpy, 5a), 4,40-di-tert-butyl-2,20-bipyridine (tbbp, 5b))
and XyNC. The crystal structures of complexes 2i, 20a, 3, and 6 have been determined, and the
electrochemical behavior of 2i has been studied.
Introduction
to prepare a variety of iminobenzoyl palladium complexes
(I; Scheme 1)1-6 as well as some heterocycles (for example,
II).3,7 Additionally, sometimes metalated heterocycles (for
example III) form after an intramolecular process.6,8
We are studying the synthesis and reactivity of ortho-
functionalized aryl metal complexes. In particular, insertion
reactions of isocyanides into the Pd-C bond have allowed us
We have decided to study the reactivity of our ortho-functio-
nalized iminobenzoyl complexes I with the hope that interesting
results could arise due to the modified reactivity imposed by the
metal center on both the X and -CdNR groups (Scheme 1) or
to their joint reactivity favored by their vicinity. This paper
describes the first results of this novel approach, namely, the
synthesis of a family of 1,2-dihydro-3-xylylbenzoquinazoli-
nium-4-yl palladium complexes (IV; Scheme 1) by reacting
2-aminoxylyliminobenzoyl palladium complexes (I, R = Xy,
X=NH2) with carbonyl compounds (aldehydes or ketones) and
an acid. A different method described recently by us gave the
first two 1,2-dihydroquinazolinium-4-yl complexes;6 however it
lacks the applicability of the present method.
*To whom correspondence should be addressed. E-mail: jvs1@um.es.
Web: http://www.um.es/gqo/.
†To whom correspondence should be addressed regarding the X-ray
diffraction studies. E-mail: dbc@um.es.
ꢀ
(1) Vicente, J.; Abad, J. A.; Frankland, A. D.; Lopez-Serrano, J.;
Ramırez de Arellano, M. C.; Jones, P. G. Organometallics 2002, 21, 272.
(2) Vicente, J.; Abad, J. A.; Shaw, K. F.; Gil-Rubio, J.; Ramırez de
Arellano, M. C.; Jones, P. G. Organometallics 1997, 16, 4557. Vicente, J.;
€
Abad, J. A.; Fortsch, W.; Jones, P. G.; Fischer, A. K. Organometallics 2001,
ꢀ
20, 2704. Vicente, J.; Abad, J. A.; Hernandez-Mata, F. S.; Rink, B.; Jones,
P. G.; Ramírez de Arellano, M. C. Organometallics 2004, 23, 1292.
€
(3) Vicente, J.; Saura-Llamas, I.; Grunwald, C.; Alcaraz, C.; Jones,
P. G.; Bautista, D. Organometallics 2002, 21, 3587. Vicente, J.; Abad,
J. A.; Martínez-Viviente, E.; Jones, P. G. Organometallics 2003, 22, 1967.
Vicente, J.; Abad, J. A.; Lopez-Serrano, J.; Jones, P. G.; Najera, C.; Botella-
Segura, L. Organometallics 2005, 24, 5044. Vicente, J.; Saura-Llamas, I.;
García-Lopez, J. A.; Bautista, D. Organometallics 2009, 28, 448.
(4) Vicente, J.; Abad, J. A.; Martınez-Viviente, E.; Jones, P. G.
Quinazoline-based structures have attracted considerable atte-
ntion over the years since they are present in many natural or
synthetic products with interesting pharmacological antitumor,
antidepressant, anti-inflammatory, or antimalaria properties.9,10
ꢀ
ꢀ
ꢀ
Organometallics 2002, 21, 4454.
(5) (a) Vicente, J.; Abad, J. A.; Lopez-Serrano, J.; Clemente, R.;
ꢀ
Ramırez de Arellano, M. C.; Jones, P. G.; Bautista, D. Organometallics
ꢀ
ꢀ
€
ꢀ
(8) Vicente, J.; Abad, J. A.; Lopez-Serrano, J.; Jones, P. G. Organo-
metallics 2004, 23, 4711.
(9) (a) Michael, J. P. Nat. Prod. Rep. 2008, 25, 166. (b) Tinker, A. C.;
Beaton, H. G.; Boughton-Smith, N.; Cook, T. R.; Cooper, S. L.; Fraser-Rae,
L.; Hallam, K.; Hamley, P.; McInally, T.; Nicholls, D. J.; Pimm, A. D.;
Wallace, A. V. J. Med. Chem. 2003, 46, 913.
2003, 22, 4248. (b) Vicente, J.; Abad, J. A.; Lopez-Saez, M. J.; Fortsch, W.;
Jones, P. G. Organometallics 2004, 23, 4414.
(6) Vicente, J.; Chicote, M. T.; Martınez-Martınez, A. J.; Jones, P. G.;
Bautista, D. Organometallics 2008, 27, 3254.
ꢀ
(7) Vicente, J.; Saura-Llamas, I.; Garcıa-Lopez, J. A.; Calmuschi-Cula,
B.; Bautista, D. Organometallics 2007, 26, 2768.
r
2009 American Chemical Society
Published on Web 09/29/2009
pubs.acs.org/Organometallics

5916 Organometallics, Vol. 28, No. 20, 2009
Vicente et al.
Scheme 1. Cyclization Reactions from ortho-Substituted
Iminoacyl Palladium Complexes
Scheme 3
Scheme 2
R0 =H (2e), CHdCH2 (2f), Ph (2g), C6H4Me-4 (To) (2h),
{Fe(C5H4)(C5H5)} (Fc) (2i)) could be obtained when 1 was
reacted with HOTf and different carbonyl compounds
RC(O)R0 in CH2Cl2 or using the carbonyl compound as
solvent (2b, 2c). In general, the isolation of complexes 2 was
achieved by adding cold Et2O to the concentrated reaction
mixture and stirring the suspension in a cold bath because
otherwise oily materials tend to form.
The synthesis of the first 1,2-dihydroquinazolinium-4-yl (in
what follows DHQ) metal complexes, namely, trans-[PdI2-
{CdN(Xy)C(Me){CH2C(O)Me}NHC6H4-2}(CNXy)L] (L=
PPh3, CNXy), was recently reported by us through an in-
tramolecular process that lacks the wide applicability of the
method we report here.6
Nonmetalated 1,2-dihydroquinazolinium derivatives have been
prepared through a variety of methods with the participation, in
some cases, of Li or Grignard derivatives.10,11 The method
reported herein could open ways for the stoichiometric or
catalytic synthesis of dihydroquinazoline derivatives, which
could also form by depalladation of our complexes.
Results and Discussion
In search of the reaction pathway leading to complexes 2,
we have considered (Scheme 3) protonation followed by a
condensation reaction (1 f A f B f 2) and the opposite
sequence (1 f C f B f 2). With this purpose, the reaction of
1 with triflic acid in CH2Cl2 was studied. Although proton-
ation of other palladium iminoacyl complexes has been
previously found to give readily the corresponding iminium-
benzoyl species,6,12 the expected complex A ([Pd] =
[PdI(CNXy)2], Scheme 4) was not isolated. Instead, the
reaction led to precipitation of the chelate complex SP-4-
4-[PdI{C,N-C(dNHXy)C6H4NH2-2}CNXy]OTf (3), result-
ing after protonation of the iminobenzoyl nitrogen atom and
XyNC replacement. Probably, the protonation of the imino-
Synthesis and Reaction Pathway. While studying the reac-
tivity of different iminobenzoyl palladium complexes toward
a variety of reagents, we found that protonation of
trans-[PdI{C(dNXy)C6H4NH2-2}(CNXy)2]1 (1, Scheme 2)
with HOTf (OTf=O3SCF3) in acetone afforded trans-[PdI-
{CdN(Xy)CMe2NHC6H4-2}(CNXy)2]OTf (2a). The scope
of this reaction is quite general because similar com-
plexes [PdI{CdN(Xy)C(R)(R0)NHC6H4-2}(CNXy)2]OTf
(R=Me, R0 =Ph (2b), CH2C(O)Me (2c), H (2d), R=H,
(10) Mikiciuk-Olasik, E.; Blaszczak-Swiatkiewiz, K.; Urek, E.;
Krajewska, U.; Rozalski, M.; Kruszynski, R.; Bartczak, T. J. Arch.
Pharm. Pharm. Med. Chem. 2004, 337, 239.
(11) Finch, N.; Gschwend, H. W. J. Org. Chem. 1971, 36, 1463.
Carrington, H. C. J. Chem. Soc. 1955, 2527. Strekowski, L.; Cegla, M. T.;
Harden, D. B.; Mokrosz, J. L.; Mokrosz, M. J. Tetrahedron Lett. 1988, 29,
4265. Strekowski, L.; Cegla, M. T.; Suk-Bin, K.; Harden, D. B. J. Hetero-
cycl. Chem. 1989, 26, 923. Lessel, J. Arch. Pharm. 2006, 328. Field, G. F.;
Zally, W. J.; Sternbach, L. H. J. Org. Chem. 1965, 30, 3957. Okada, E.;
acyl group gives A by splitting the intramolecular N-H
N
3 3 3
hydrogen bond present in 1,1 which allows the displacement
of one of the XyNC ligands by the NH2 group favored by the
chelate effect and the insolubility of 3. From the reaction of 3
with excess XyNC (1:1.2) in CH2Cl2 we could not isolate
€
Tsukushi, N. Heterocycles 1999, 2471. Schopf, C.; Oechler, F. Justus
Liebigs Ann. Chem. 1936, 523, 1.
(12) Owen, G. R.; Vilar, R.; White, A. J. P.; Williams, D. J.
Organometallics 2003, 22, 4511.

Article
Organometallics, Vol. 28, No. 20, 2009 5917
Scheme 4
Scheme 5
obtained when we attempted to grow single crystals of 4.
Therefore, in solution it behaves as we assume for its homo-
logue A, although more slowly. The decomposition of 4 into
3 is favored by the chelate effect and the strong transphobic
effect1,4,13 between the iminiumbenzoyl and PPh3 ligands.14
In agreement with our expectations, 4 reacted with RC-
(O)R0 to give SP-4-3-[PdI{CdN(Xy)C(R)(R0)NHC6H4-2}-
(CNXy)(PPh3)]OTf (R=R0 =Me (20a), R=H, R0 =CH-
(Me)Ph (20b), To (20c)), and 3 reacted with PPh3 in acetone to
afford 20a. Therefore, complex 4 is an isolated complex of
type A that behaves as an intermediate in the synthesis of
DHQ complexes.
We have also considered the reverse reaction pathway 1 f
C f B f 2 (Scheme 3), involving condensation of 1 with
RC(O)R0 followed by the protonation and cyclization pro-
cesses. Complex 1 did not react with acetone or ToCHO even
by refluxing the mixture in the presence of molecular sieves,
and when 0.1 equiv of HOTf was added to catalyze the
process, only a 10:1 1:2a or 1:2h mixture, respectively, was
isolated. However, we have independently prepared the
C-type complex with R=H, R0 =To (Scheme 5). Thus, the
reaction of IC6H4NdCHTo-2 with Pd(dba)2 and N^N (1:1:1)
afforded [PdI(C6H4NdCHTo-2)(N^N)] (N^N^= bpy (5a),
tbbpy (5b)), which, in turn, reacted with XyNC (1:3) to
yield trans-[PdI{C(dNXy)C6H4NdCHTo-2}(CNXy)2] (6,
Scheme 2). The C-type complex 6 reacted inmediately with
HOTf to give complex 2h.
complex A; a mixture formed instead, which, upon recrys-
tallization, gave 3 as the only identified product. However,
this reaction in acetone gives, probably through A, complex
2a (Scheme 4) although in lower yield than starting from 1.
Likely, in acetone some side products are also formed. The
reaction of 1 with HOTf and acetophenone or acetylacetone
gives, along with 2b or 2c, appreciable amounts of complex 3,
even when the ketones are used as solvents. The reaction of 1
with HOTf and benzophenone (1:1:10, in CH2Cl2, 3.5 h)
gave 70% yield of complex 3, while only traces of the
expected complex trans-[PdI{CdN(Xy)CPh2NHC6H4-2}-
(CNXy)2]OTf could be observed in the 1H NMR spectrum
of the mother liquor. This suggests that for bulky ketones a
slow condensation reaction (A f B, Scheme 3) allows the
chelation reaction (A f 3, Scheme 4) to take place. In these
cases, the reaction workup is not as straigthforward and the
yield of complexes 2b and 2c is low.
The reaction of 3 with PPh3 (1:1.2, CH2Cl2) afforded the
A-type complex SP-4-3-[PdI{C(dNHXy)C6H4NH2-2}-
(CNXy)(PPh3)]OTf (4, Scheme 4). Although this complex
was characterized by elemental analyses and 1H NMR,
neither its 13C NMR spectrum nor its crystal structure could
be obtained because it slowly decomposes back to 3. In fact,
crystals of 3 suitable for an X-ray diffraction study were
Since both the reaction of 4 with acetone and that of 6 with
HOTf produced 20a and 2h, respectively, we believe that both
reaction pathways (1 f A f B f 2 and 1 f C f B f 2) could
be involved in the cyclization process. Although we have not
detected intermediate C from 1, its formation in trace
amounts cannot be discharged, and its fast reaction with
acid could give the DHQ complexes.
(13) Vicente, J.; Arcas, A.; Bautista, D.; Tiripicchio, A.; Tiripicchio-
ꢀ
Camellini, M. New J. Chem. 1996, 20, 345. Vicente, J.; Arcas, A.; Galvez-
ꢀ
ꢀ
ꢀ
Lopez, M.-D.; Julia-Hernandez, F.; Bautista, D.; Jones, P. G. Organometal-
lics 2008, 27, 1582. Vicente, J.; Arcas, A.; Bautista, D.; Jones, P. G.
Organometallics 1997, 16, 2127. Vicente, J.; Chicote, M. T.; Rubio, C.;
Ramírez de Arellano, M. C.; Jones, P. G. Organometallics 1999, 18, 2750.
(14) Albert, J.; Bosque, R.; Cadena, J. M.; Delgado, S.; Granell, J.
J. Organomet. Chem. 2001, 634, 83. Casas, J. M.; Fornies, J.; Fuertes, S.;
Martin, A.; Sicilia, V. Organometallics 2007, 26, 1674. Fernandez-Rivas, C.;
Cardenas, D. J.; Martin-Matute, B.; Monge, A.; Gutierrez-Puebla, E.;
Echavarren, A. M. Organometallics 2001, 20, 2998. Han, Y.; Lee, L. J.;
Huynh, H. V. Organometallics 2009, 28, 2778. Jalil, M. A.; Fujinami, S.;
Nishikawa, H. J. Chem. Soc., Dalton Trans. 2001, 1091. Marshall, W. J.;
Grushin, V. V. Organometallics 2003, 22, 555. Ng, J. K. P.; Chen, S.; Li, Y.;
Tan, G. K.; Koh, L. L.; Leung, P. H. Inorg. Chem. 2007, 46, 5100.
ꢀ
ꢀ
Vicente, J.; Arcas, A.; Fernandez-Hernandez, J. M.; Bautista, D. Organo-
metallics 2001, 20, 2767. Vicente, J.; Abad, J. A.; Frankland, A. D.; Ramírez
de Arellano, M. C. Chem.;Eur. J. 1999, 5, 3066. Vicente, J.; Abad, J. A.;
ꢀ
Hernandez-Mata, F. S.; Jones, P. G. J. Am. Chem. Soc. 2002, 124, 3848.
ꢀ
ꢀ
Vicente, J.; Arcas, A.; Galvez-Lopez, M. D.; Jones, P. G. Organometallics
2006, 25, 4247. Vicente, J.; Arcas, A.; Blasco, M. A.; Lozano, J.; Ramírez de
Arellano, M. C. Organometallics 1998, 17, 5374.

5918 Organometallics, Vol. 28, No. 20, 2009
Vicente et al.
Figure 2. Crystal structure of the cation of 20a H2O. The
3
thermal ellipsoids are displayed at 50% probability. Hydrogen
atoms and solvent are omitted for clarity. Selected bond lengths
˚
(A) and angles (deg): Pd-C(1) 1.967(3), Pd-C(21) 2.053(2),
Pd-P 2.3456(6), Pd-I 2.5983(2), C(21)-C(22) 1.443(3), C-
(22)-C(23) 1.419(3), N(3)-C(21) 1.315(3), N(3)-C(31)
1.459(3), N(3)-C(41) 1.531(3), N(4)-C(23) 1.360(3), N(4)-C-
(41) 1.452(3); C(1)-Pd-C(21) 89.50(9), C(1)-Pd-P(1)
89.36(7), P-Pd-I 93.478(16), C(21)-Pd-I 87.47(6).
Figure 1. (Top) Crystal structure of the cation of 2i CHCl3.
3
The thermal ellipsoids are displayed at 50% probability. Hydro-
gen atoms and solvent are omitted for clarity. Selected bond
˚
lengths (A) and angles (deg): Pd-C(1) 1.965(2), Pd-C(11)
1.967(2), Pd-C(21) 2.0311(19), Pd-I 2.6421(3), C(21)-C(22)
1.441(3), C(22)-C(23) 1.418(3), N(3)-C(21) 1.310(3), N(3)-C-
(31) 1.452(2), N(3)-C(41) 1.513(2), N(4)-C(23) 1.358(3),
N(4)-C(41) 1.434(3); C(1)-Pd-C(21) 87.41(8), C(11)-Pd-C-
(21) 92.71(7), C(1)-Pd-I 91.15(6), C(11)-Pd-I 88.48(6).
(Bottom) Packing diagram: C(37)-H(37) 0.98, H(37) I#1
3 3 3
Figure 3. Crystal structure of the cation of 3 CH2Cl2. The
3
3.09, C(37) I#1 3.914, C(37)-H(37)-I#1 142.1. Hydrogen
atoms, except H(37), are omitted for clarity.
3 3 3
thermal ellipsoids are displayed at 50% probability. Solvent is
˚
omitted for clarity. Selected bond lengths (A) and angles (deg):
Crystal Structures. The crystal structures of complexes
2i CHCl3 (Figure 1), 20a H2O (Figure 2), 3 CH2Cl2
Pd-C(1) 2.009(3), Pd-C(8) 1.930(3), Pd-N(1) 2.073(3), Pd-I
2.6391(3), C(1)-N(2) 1.282(4); C(1)-Pd-C(8) 97.04(12), C-
(1)-Pd-N(1) 80.73(11), C(8)-Pd-I 90.12(9), N(1)-Pd-I
91.92(7).
3
3
3
(Figure 3), and 6 (Figure 4) have been determined by X-ray
diffraction. Those of 2f, 2h, and 5a will be published elsewhere.
The palladium atom in all of them is in a distorted square-planar
environment. In complexes 2i and 20a (in what follows com-
plexes 2) the heterocycle adopts a boat conformation with C(22)
and C(41) out of the plane formed by the four other atoms. The
C(22)-C(21)-N(3) plane is almost perpendicular to both the
coordination and the C(31)fC(36) xylyl planes (torsion angles
The common DHQ skeleton in complexes 2 (Figures 1 and
2) shows similar bond distances and angles. The Pd-C(21)
0
˚
˚
bond distance in 2i (2.0311(19) A) < 2 a (2.053(2) A) shows
the trans influence sequence I < PPh3. The Pd-C(1) bond
length in 3 (2.009(3)) is significantly shorter than the above
C(DHQ)-Pd distances probably due to the chelating nature
of the orthoamino-iminiumacyl ligand. The stereochemistry
in 20a, in spite of the great C/P transphobia1,4,13 between the
DHQ and PPh3 ligands,14 is probably due to steric reasons.
79.4°, 72.1° (2i), 94.4°, 98° (20a)). The molecules of 2i CHCl3
3
pack into dimers (Figure 3) due to C(37)-H(37C) I#1
3 3 3
hydrogen bonds. Complex 3 shows D-H OOTf hydrogen
bond interactions, where D is C(28), C(7), N(1), and N(2).
3 3 3

Article
Organometallics, Vol. 28, No. 20, 2009 5919
Chart 1
˚
˚
Xy-N length is shorter in 6 (1.414(4) A vs 1.452(2) A)
probably due to the XyN H hydrogen bond in 1. Addi-
˚
tionally, the iminoacyl CdN bond distance in 6 (1.263(4) A)
3 3 3
˚
is shorter than that in the imino CdN group (1.281(4) A),
which in turn is similar to that of the iminiumacyl CdN bond
˚
in 3 (1.282(4) A) or even shorter than that in complexes 2
0
˚
˚
(1.315(3) A (2 a), 1.310(3) A (2i)). The molecules of 6
(Figure 4) pack into chains along the b axis due to inter-
molecular C(36)-H(36) I(2)#1 hydrogen bonds in which
3 3 3
the tolyl group is involved.
Comparison of the Pd-I bonds in all these complexes
suggests the trans influence of the ligands to follow the series
˚
˚
DHQ (2.6421(3) A (2i)) ∼ iminiumacyl (2.6391(3) A (3)) >
0
˚
XyNC (2.5983(2) A (2 a)). The neutral nature of 6 can be
˚
responsible for its long Pd-I bond distance (2.7164(3) A)
compared to that in the other cationic complexes because all
have a carbon donor ligands trans to I.
IR and NMR Spectra. Complexes 2a-i show in their IR
spectra a single ν(CtN) band indicating the mutually trans
disposition of the two XyNC ligands in the solid state, as has
been established in the X-ray diffraction studies of com-
plexes 2f, 2h, and 2i. Some NMR data also confirm this
disposition in solution (see below).
Figure 4. (Top) Crystal structure of complex 6. The thermal
ellipsoids are displayed at 50% probability. Selected bond
lengths (A) and angles (deg): Pd-C(1) 1.977(3), Pd-C(11)
1.972(3), Pd-C(20) 2.050(3), Pd-I(2) 2.7164(3), C(20)-N(4)
1.263(4), N(4)-C(41) 1.414(4), C(20)-C(21) 1.493(4), N(5)-C-
(27) 1.281(4); C(1)-Pd-C(20) 89.04(11), C(1)-Pd-I(2)
88.58(9), C(11)-Pd-C(20) 90.67(12), C(11)-Pd(1)-I(2)
91.70(9). (Bottom) Packing diagram. C(36)-H(36) 0.95,
The NMR spectra of 2a and 2e (R = R0 = Me, H,
respectively) show, as expected, single resonances for the R
substituents and the methyls in the xylyl groups Xy-NdC
(Xyq) and Xy-NCPd (XyPd; see Chart 1). The same is
observed in the room-temperature 1H and 13C NMR spectra
of complexes 2b and 2c, showing that rotation around the
Pd-C1, N-XyPd, and N-Xyq bonds is fast enough at room
temperature to allow the observed equivalence of methyl
groups, in spite of R ¼ R0. In solutions of 2b at -40 °C the
Xyq methyl protons become inequivalent, but the XyPd
methyl protons remain isochronous. However, at -60 °C
˚
H(36) I(2)#13.13, C(36) I(2)#1 3.861(3); C(36)-H(36)-I-
3 3 3 3 3 3
(2)#1 135.2.
However, in 3 the isocyanide ligand is trans to the NH2 group
due to great C/C transphobia and because steric repulsions
are much less important than in 20a. The two pairs
of distances C(22)-C(21), Pd-C(21) and C(21)-N(3),
N(3)-C(31) in 2i (1.441(3), 2.0311(19) and 1.310(3),
the Xy methyl protons appear as singlets of 6H:6H (XyPd
)
and 3H:3H (Xyq) intensities. This is also the pattern observed
for the Xy methyl resonances in the spectra of 2c at -40 °C
and in those of the remaining complexes 2 at room tempera-
ture. The differences observed should be attributed to elec-
tronic rather than steric effects in view of the bulkier
substituents in 2b (R = Me, R0 = Ph) than in 2g (R = H,
R0=Ph) or in 2c (R=Me, R0=CH2C(O)Me) than in 2f (R=
H, R0=CHdCH2).
˚
1.452(2) A, respectively) are shorter and longer, respectively,
than those in its parent complex 1 (1.486(5), 2.059(4) and
1
1.264(5), 1.417(5) A, respectively). Both observations sug-
˚
gest a migration of π-electron density from the Xy-NdC-
(21) fragment to the C-C-Pd moiety due to the cyclization
process. In general, the C(22)-C(21) bond lengths are short-
er and the pair of bond distances N(3)-C(21), N(3)-C(31)
are longer in complexes 2 than in other palladium xylylimi-
We assume complexes 20a-c to have in solution the same
geometry as that determined for 20a in the solid state by
X-ray crystallography on the basis of the similar position of
the 31P NMR resonances (14.4-15.1 ppm) and the JPC1
values (152-153 Hz). In 20a, with R=R0 =Me, the XyPd
methyl protons are equivalent, while the Xyq ones are not,
which suggests that fast rotation around the N-XyPd bond
occurs, while rotation around N-Xyq and Pd-C1 bonds is
slow on the NMR time scale. This is also observed in 20b and
20c. Thus, two stereoisomers of 20c are observed due to the
slow rotation around the Pd-C1 on the NMR time scale and
the different nature of the two ligands cis to the iminobenzoyl
group, I and XyNC (cis effect). Both factors and the chirality
nobenzoyl complexes:1,2,4,15 1.441(3)-1.449(3) A vs 1.476-
˚
˚
˚
˚
1.512 A, 1.310(3)-1.318(3) A vs 1.251-1.283 A, and 1.454-
˚
˚
(3)-1.459(3) A vs 1.392-1.453 A, respectively.
The structure of complex 6 (Figure 4) shows in its fragment
Xy-NdC(C)-Pd, the Pd-C, CdN, and C-C bond dis-
tances (2.050(3), 1.263(4), 1.493(4) A, respectively), similar
˚
1
to those in 1 (2.059(4), 1.264(5), 1.486(5) A), while the
˚
(15) Cambridge Structural Database, versioꢀn 5.30; Cambridge Crystal-
lographic Data Centre: Cambridge, U.K., November 2008; www.ccdc.cam.
ac.uk

5920 Organometallics, Vol. 28, No. 20, 2009
Vicente et al.
of the C*HPh(Me) (R0) carbon explain the formation of four
stereoisomers of 20b, which requires that the chirality of the
C*RR0 carbon is not fully determined by that of the CHPh-
(Me) group; that is, the diastereoisomeric excess (de) induced
on the CRR0 group by the chirality of the R0 group (ketone
chirality effect) is <100%. According to 1H and 31P NMR
spectra, the cis effect is quite important because it induces a
6:1 molar ratio of stereoisomers in 20c (71% de). The
four stereoisomers in 20b form in 12:4:3:1 molar ratios. The
12:3=4:1 (60% de) molar ratios can be related with one of
the two effects, while the other must be responsible for the
12:4=3:1 molar ratios (50% de). It is reasonable to assume
that the greater diastereoisomeric ratio is related to the cis
effect, while the second one is due to the ketone chirality
effect.
Conclusion and Prospects
A general method for the synthesis of 1,2-dihydro-3-
xylylquinazolinium-4-yl (DHQ) palladium complexes invol-
ving the reaction between an orthoamino-iminoacyl palla-
dium complex, a carbonyl compound, and an acid is
reported. Some of the probable intermediates have been
isolated and their reactivity studied, showing them to behave
as expected in the proposed reaction pathway. Thus, the
synthesis of some orthoamino-iminiumacyl complexes has
allowed us to prove that they react with carbonyl compounds
to give DHQ palladium complexes. Alternatively, we have
prepared an orthoimino-iminoacyl complex and reacted it
with an acid to give a DHQ palladium complex. Experiments
will be carried out (1) to prepare oligomers and dendrimers
by choosing the appropriate carbonyl compounds and (2) to
prepare mono- or poly-1,2-dihydro-3-(R)-quinazolinium-
4-yl derivatives by depalladation.
Iminoacyl complexes of the type [Pd]{C(dNXy)Ar}6
show the resonance due to the carbon atom bonded to Pd
at 170-180 ppm (including complex 6, 176.4 ppm;
Scheme 5). Formation of the DHQ ring results in an appreci-
able deshielding of this nucleus (199.1-205.4 ppm in 2, 20;
not observed in 3). Such deshielding is even greater in the
DHQ complexes trans-[PdI2{CdN(Xy)C(Me){CH2C-
(O)Me}NHC6H4-2}(L)] (L = CNXy, 219.2 ppm; PPh3
221.4 ppm), previously reported by us,6 probably due to
the replacement of XyNC by the more electronegative iodo
ligand. The resonance due to the XyNtC-Pd carbon
around 135 ppm is observed only in some cases.16
Experimental Section
General Procedures. When not stated, the reactions were
carried out without precautions to exclude light or atmospheric
oxygen or moisture. Melting points were determined on a
Reicher apparatus and are uncorrected. Elemental analyses
were carried out with a Carlo Erba 1106 microanalyzer. IR
spectra were recorded on a Perkin-Elmer 16F PC FT-IR spec-
trometer with Nujol mulls between polyethylene sheets. NMR
spectra were recorded in Varian 300 or 400 NMR spectrometers.
The NMR assignments were performed, in some cases, with the
help of APT, HMQC, and HMBC experiments. Chart 1 gives
the atom numbering used in NMR assignments. HOTf, XyNC,
bpy, tbbp, and ToCHO were purchased from Fluka.
In the 1H NMR spectra of the iminiumbenzoyl complexes
3 and 4 the δ(NH) resonances follow the order δ(XyNH)
(11.42-12.53 ppm) > δ(Pd-NH2) (3, 7.56 ppm) > δ(NH2)
(4, 6.07 ppm). The increase in the shielding constant is
parallel to the decrease of the formal charge at N. Complex
4 is rather insoluble in CDCl3 and scarcely stable in solution,
which prevented registering its 13C NMR spectrum or grow-
[Pd2(dba)3] dba (“Pd(dba)2”)18 was prepared as reported in
3
the literature. Although the synthesis of trans-[Pd{C-
(dNXy)C6H4NH2-2}I(CNXy)2] (1) in two steps was previously
reported by us,1 we describe here a more straigtforward method
giving a higher yield. The solvents were distilled before use.
X-ray Crystallography. Compounds 2i CHCl3, 20a H2O,
ing a single crystal to determine its structure. The 1H and 31
P
NMR spectra of 4 in CDCl3 were very poorly resolved.
Although they improve when measured in CD3CN, the
resonances are broad at room temperature and even at
-40 °C. The significant difference between δ(31P) in 4 and
in complexes 20 (23.5 vs 14.4-15.1 ppm) could be due to the
solvent (CD3CN in 4 and CDCl3 in 20) or to the steric
conditions imposed by the heterocyclic ring, which certainly
stresses the coordination plane of palladium. Other factors
are equal or similar: the trans influences of DHQ and
iminiumacyl ligands (see above) and the nature of the cis
ligands.
Electrochemical Study. The voltammogram of 2i shows the
redox process to be reversible. The oxidation potential of this
complex, 200 mV higher than that of ferrocene, is in agree-
ment with the electron-withdrawing ability of the palla-
dated 1,2-dihydroquinazolinium substituent of the ferrocene
moiety and shows an efficient electronic communi-
cation between the iminoacyl nitrogen, in which the positive
charge of the substituent is mainly localized, and the iron
center.
3
3
3 CH2Cl2, and 6 were measured on a Bruker Smart APEX
3
machine. Data were collected using monochromated Mo KR
radiation in ω scan mode. The structures were solved by direct
methods. All were refined anisotropically on F2. Restraints to
local aromatic ring symmetry or light atom displacement factor
components were applied in some cases. The NH and NH2 were
refined as free with SADI in NH2 compounds, the methyl
groups were refined using a rigid groups, and the other hydro-
gens were refined using a riding mode. Special features: For
20a H2O the water hydrogens were refined as free. Further
details on crystal data, data collection, and refinements are
summarized in the Supporting Information.
3
Cyclic Voltammetry. The electrochemical experiment was
performed at 298 K with a potentiostat/galvanostat AUTO-
LAB-100 (Echo-Chemie, Utrecht) using a one-compartment
three-electrode system with a glassy carbon electrode as the
working electrode (Metrohm, 2 mm of diameter). A Ag/AgCl/
KCl (saturated) electrode was the reference and a glassy carbon
bar was the auxiliary electrode. A 2.5 mM solution of 2i in
acetonitrile with 0.4 M anhydrous lithium perchlorate as sup-
porting electrolyte and 1.5 M AcOH were purged with pure
argon prior to use, and the cyclic voltammogram was obtained
at 100 mV s-1. The value of the reduction potential is referenced
to the redox couple [Fe(C5H5)2]þ/0 (E0red=300 mV).
(16) Vicente, J.; Gil-Rubio, J.; Guerrero-Leal, J.; Bautista, D. Orga-
nometallics 2005, 24, 5634. Vicente, J.; Gil-Rubio, J.; Guerrero-Leal, J.;
Bautista, D. Organometallics 2004, 23, 4871.
(17) Vicente, J.; Chicote, M. T.; Huertas, S.; Jones, P. G.; Fischer, A.
K. Inorg. Chem. 2001, 40, 6193. Vicente, J.; Chicote, M. T.; Huertas, S.;
Bautista, D.; Jones, P. G.; Fischer, A. K. Inorg. Chem. 2001, 40, 2051.
Synthesis of trans-[PdI{C(dNXy)C6H4NH2-2}(CNXy)2] (1).1
To a suspension of “Pd(dba)2” (2.0 g, 3.48 mmol) in toluene
ꢀ
ꢀ
ꢀ
Vicente, J.; Arcas, A.; Fernandez-Hernandez, J. M.; Aullon, G.; Bautista, D.
Organometallics 2007, 26, 6155. Vicente, J.; Chicote, M. T.; Vicente-
(18) Takahashi, Y.; Ito, S.; Sakai, S.; Ishii, Y. J. Chem. Soc., Chem.
Commun. 1970, 1065.
ꢀ
Hernandez, I.; Bautista, D. Inorg. Chem. 2008, 47, 9592.

Article
Organometallics, Vol. 28, No. 20, 2009 5921
(50 mL) under a nitrogen atmosphere were successively added
XyNC (1.37 g, 10.43 mmol) and IC6H4NH2-2 (761.8 mg,
3.48 mmol) with a 15 min interval. The suspension was stirred
for 6.5 h, the solvent was removed under vacuum, and the
residue was stirred with CH2Cl2 (30 mL). The suspension was
filtered through a short pad of Celite, and the filtrate was
concentrated under vacuum to ca. 3 mL. Upon the addition of
cold Et2O (30 mL, 0 °C), a precipitate formed, which was filtered
off, washed with Et2O (3 ꢀ 3 mL), and suction dried to give 1
(1.574 g, 2.19 mmol, 63%).
Synthesis of trans-[PdI{CdN(Xy)C(Me){CH2C(O)Me}NH-
C6H4-2}(CNXy)2]OTf (2c). To a suspension of 1 (150 mg, 0.21
mmol) in acetylacetone (2 mL) was added HOTf (19 μL,
2.2 mmol). A solution formed immediately, which was stirred
for 2.5 h. Upon the addition of Et2O (25 mL) an oily material
formed, which was converted into a solid by stirring it with a
1:10 mixture of CH2Cl2 and Et2O (3 ꢀ 22 mL). The solid was
treated with CH2Cl2 (10 mL), the resulting suspension was
filtered, the solution was concentrated under vacuum (2 mL),
cold Et2O (20 mL, 0 °C) was added, and the suspension was
filtered. The solid collected was washed with Et2O (3 ꢀ 5 mL)
and dried in an oven at 70 °C for 8 h to give 2c as a lemon-yellow
solid. Yield: 70.3 mg, 0.07 mmol, 36%. Mp: 157 °C. 1H NMR
(400 MHz, CDCl3, 25 °C, TMS): δ 1.79 (s, 3 H, Me), 1.83 (s, 3 H,
Me), 2.28 (s, 12 H, Me, XyPd), 2.32 (s, 6 H, Me, Xyq), 3.15 (s br, 2
Synthesis of trans-[PdI{CdN(Xy)CMe2NHC6H4-2}(CNXy)2]-
TfO (2a). To a solution of 1(150 mg, 0.21 mmol) in acetone (15 mL)
was added HOTf (18.5 μL, 0.21 mmol). The reaction mixture was
stirred for 2 h and concentrated under vacuum to 1 mL, and Et2O
(20 mL) was added. A suspension formed, which was filtered, and
the solid collected was dried first by suction and then in an oven at
70 °C for 4 h to give 2a as a lemon-yellow solid. Yield: 151.6 mg,
H, CH2), 7.04 (t, 1 H, H6, 3JHH=7 Hz), 7.14 (d, 4 H, meta-XyPd
,
3JHH=8 Hz,), 7.19 (d, 2 H, meta-Xyq, 3JHH=8 Hz,), 7.29-7.40
(m, 4 H), 7.58 (t, 1 H, H5, 3JHH=7 Hz), 8.23 (d, 1 H, H7, 3JHH=8
Hz), 8.32 (s br, 1 H, NH); (400 MHz, CDCl3, -40 °C, TMS):
δ 1.78 (s, 3 H, Me), 1.84 (s, 3 H, Me), 2.25 (s, 9 H, Me, Xyq þ
XyPd), 2.30 (s, 6 H, Me, XyPd), 2.37 (s, 3 H, Me, Xyq), 3.16 (AB
system, 2H, CH2, νA=3.26, νB=3.05, JAB=15 Hz), 7.08 (t, 1 H,
3JH3H=7 Hz), 7.17-7.25 (m, 6 H), 7.34-7.42 (m, 4 H), 7.62 (t, 1
H, JHH = 8 Hz), 8.25 (overlapped dþbr s, 2 H, NH þ H7).
13C{1H} NMR (75.5 MHz, CDCl3, 25 °C, TMS): δ 17.9 (Me,
XyPd), 20.0 (Me, Xyq), 22.9 (Me), 31.3 (C(O)Me), 78.6 (C8),
117.8 (C4), 120.1 (C6), 125.8 (C2), 128.6 (meta-CH, XyPd), 129.9
(br, meta-Xyq), 130.1 (para-Xyq), 131.3 (para-XyPd), 135.6 (C7),
136.2 (ortho-XyPd), 138.6 (C5), 141.3 (C3), 141.7 (ipso-Xyq),
203.7 (C1), 204.0 (CO). IR (Nujol, cm-1): ν(NH) = 3219,
ν(CtN) 2194, ν(CdO), ν(CdN þ CdC) 1720, 1616, 1533.
ΛM=140 Ω-1 cm2 mol-1. Anal. Calcd for C39H40F3IN4O4PdS:
C, 49.25; H, 4.24; N, 5.89; S, 3.37. Found: C, 48.83; H, 3.86; N,
5.84; S, 3.29.
1
0.17 mmol, 80%. Dec pt: 208 °C. H NMR (300 MHz, CDCl3,
25 °C, TMS): δ 1.65 (s, 6 H, Me, CMe2), 2.26 (s, 12 H, Me, XyPd),
2.28 (s, 6 H, Me, Xyq), 6.97 (ddd, 1 H, H6, 3JHH=8 Hz, 3JHH=7 Hz,
4JHH=1 Hz), 7.14 (d, 4 H, meta-XyPd, 3JHH=8 Hz), 7.20 (d, 2 H,
meta-Xyq, 3JHH=8 Hz), 7.29-7.38 (m, 3 H, para-XyqþPd), 7.39 (d,
1 H, H4, 3JHH=8 Hz), 7.54 (dd, 1 H, H5, 3JHH=8 Hz, 3JHH=7 Hz),
8.22 (dd, 1 H, H7, 3JHH=8 Hz, 4JHH=1 Hz), 8.29 (s br, 1 H, NH).
13C{1H} NMR (75.5 MHz, CDCl3, 25 °C, TMS): δ 18.6 (Me,
XyPd), 19.8 (Me, Xyq), 24.9 (CMe2), 77.2 (C8), 117.8 (C4), 118.5
(C6), 120.6 (q, TfO, 1JCF=320 Hz), 124.4 (ipso-C, XyPd), 125.4 (C2),
128.6 (meta-CH, XyPd), 129.7 (meta-Xyq), 129.8 (para-Xyq), 131.3
(para-XyPd), 134.5 (ortho-C, Xyq), 135.5 (CtNXyPd), 135.5 (C7),
136.2 (ortho-C, XyPd), 138.4 (C5), 141.6 (ipso-C, Xyq), 142.5 (C3),
202.1 (C1). IR (Nujol, cm-1): ν(CtN) 2199. Anal. Calcd for
C37H38F3IN4O3PdS: C, 48.88; H, 4.21; N, 6.16; S, 3.53. Found:
C, 49.05; H, 4.23; N, 6.06; S, 3.35.
Synthesis of trans-[PdI{CdN(Xy)C(Me)(Ph)NHC6H4-2}-
(CNXy)2]OTf (2b). To a solution of 1 (120 mg, 0.17 mmol) in
acetophenone (2 mL) was added HOTf (15 μL, 0.17 mmol), and
the reaction mixture was stirred for 2.5 h. Upon the addition of
cold Et2O (40 mL, 0 °C) to the resulting solution, a suspension
formed, which was filtered. The solid collected was recrystal-
lized from CH2Cl2 (1 mL) and n-pentane (20 mL) at 0 °C,
washed with cold pentane (3 ꢀ 5 mL, 0 °C), and dried in an oven
Synthesis of trans-[PdI{CdN(Xy)CH(Me)NHC6H4-2}(CN-
Xy)2]OTf (2d). To a solution of 1 (150 mg, 0.21 mmol) in
CH2Cl2 (20 mL) were successively added acetaldehyde
(100 μL, 1.77 mmol) and HOTf (19 μL, 0.22 mmol). The reaction
mixture was stirred for 2 h and concentrated under vacuum
(1 mL). Upon the addition of Et2O (20 mL), a suspension
formed, which was filtered. The solid collected was suction dried
to give 2d as a yellow solid. Yield: 166.3 mg, 0.19 mmol, 89%.
Dec pt: 199 °C. 1H NMR (300 MHz, CDCl3, 25 °C, TMS): δ 1.55
(d, 3 H, 3JHH=6 Hz, CHMe), 2.23 (s, 3 H, Me, Xyq), 2.26 (s, 6 H,
Me, XyPd), 2.28 (s, 6 H, Me, XyPd), 2.35 (s, 3 H, Me, Xyq), 5.28
(q, 1 H, 3JHH=6 Hz, CHMe), 6.96 (ddd, 1 H, H6, 3JHH=8 Hz,
3JHH=7 Hz, 4JHH=1 Hz), 7.11-7.17 (m, 5 H), 7.24-7.38 (m,
5 H), 7.52 (ddd, 1 H, H5, 3JHH=8 Hz, 3JHH=7 Hz, 4JHH=1 Hz),
8.10 (s br, 1 H, NH), 8.16 (dd, 1 H, H7, 3JHH=8 Hz, 4JHH=1
Hz). 13C{1H} NMR(75.5 MHz, CDCl3, 25 °C, TMS): δ 17.3
(Me), 18.6 (Me, XyPd), 18.7 (Me, XyqþPd), 19.4 (Me, Xyq), 71.0
(N2CHMe), 117.3 (C4), 119.6 (C5), 124.1 (C2), 128.6 (meta-
XyPd), 129.4 (meta-Xyq), 129.9 (meta-Xyq), 130.1 (para-Xyq),
131.3 (para-XyPd), 131.4 (para-XyPd), 133.5 (ortho-Xyq), 134.1
(ortho-Xyq), 136.0 (ortho-XyPd), 136.1 (C7), 136.5 (ortho-XyPd),
138.6 (C6), 141.8 (ipso-Xyq), 143.9 (C3), 203.3 (C1). IR (Nujol,
cm-1): ν(NH) 3237, ν(CtN) 2194, ν(CdN þ CdC) 1615, 1526.
ΛM=146 Ω-1 cm2 mol-1. Anal. Calcd for C36H36F3IN4O3PdS:
C, 48.30; H, 4.05; N, 6.26; S, 3.58. Found: C, 48.07; H, 3.81;
N, 6.20; S, 3.48.
at 70 °C for 4 h to give 2b 2H2O as a yellow solid. Yield: 74.2 mg,
3
0.07 mmol, 44%). Dec pt: 141 °C. 1H NMR (400 MHz, CDCl3,
25 °C, TMS): δ 1.58 (br, 2 H, H2O), 2.00 (s, 3 H, Me), 2.22 (s, 12
=
H, Me, XyPd), 2.24 (s, 6 H, Me, Xyq), 6.95 (ddd, 1 H, H6, 3JHH
8 Hz, 3JHH=7 Hz, 4JHH=2 Hz), 7.07-7.15 (m, 9 H), 7.24-7.34
3
(m, 3 H), 7.49-7.56 (m, 4 H), 8.17 (d, 1 H, H7, JHH=8 Hz,
4JHH=1 Hz), 8.95 ppm (s br, 1 H, NH). 1H NMR (400 MHz,
CDCl3, -40 °C, TMS): δ 2.00 (s, 3 H, Me), 2.19 (s, 3 H, Me,
Xyq), 2.22 (s, 12 H, Me, XyPd), 2.26 (s, 3 H, Me, Xyq), 6.99 (t, 1
H, H6, 3JHH=7 Hz), 7.09-7.20 (m, 9 H), 7.28-7.40 (m, 3 H),
7.46-7.51 (m, 3 H), 7.57 (dt, 1 H, H5, 3JHH=8 Hz, 4JHH=1 Hz),
8.20 (d, 1 H, H7, 3JHH=7 Hz), 8.77 (s br, 1 H, NH). 1H NMR
(400 MHz, CDCl3, -60 °C, TMS): δ 2.00 (s, 3 H, Me), 2.20 (s, 3
H, Me, Xya), 2.21 (s, 6 H, Me, XyPd), 2.22 (s, 6 H, Me, XyPd),
2.27 (s, 3 H, Me, Xya), 7.00 (t, 1 H, H6, 3JHH=8 Hz), 7.10-7.24
(m, 9 H), 7.30-7.41 (m, 3 H), 7.43-7.51 (m, 3 H), 7.59 (t, 1 H,
H5, 3JHH=8 Hz), 8.21 (d, 1 H, H7, 3JHH=8 Hz), 8.72 (s br, 1 H,
NH). 13C{1H} NMR (100.8 MHz, CD2Cl2, 25 °C, TMS): δ 18.8
(Me, XyPd), 20.9 (Me, Xyq), 25.5 (Me), 83.2 (C8), 117.6 (C4),
120.4 (C6), 124.9 (ipso-C, XyPd), 126.2 (C2), 127.5 (ortho-Ph),
128.3 (meta-Ph), 128.9 (meta-XyPd), 129.7 (para-Ph), 130.0
(para-Xyq), 130.1 (meta-Xyq), 131.6 (para-XyPd), 135.4 (ortho-
Xyq), 136.2 (C7), 136.7 (ortho-XyPd), 138.4 (ipso-Ph), 139.1 (C5),
142.7 (ipso-Xyq), 143.1 (C3), 205.4 (C1). IR (Nujol, cm-1):
Synthesis of trans-[PdI{CdN(Xy)CH2NHC6H4-2}(CNXy)2]-
OTf (2e). To a solution of 1 (120 mg, 0.17 mmol) in CH2Cl2
(20 mL) were successively added para-formaldehyde (5 mg, 0.17
mmol) and HOTf (15 μL, 0.17 mmol). The reaction mixture was
stirred for 3 h and filtered through a short pad of Celite. The
solution was concentrated under vacuum (2 mL), Et2O (20 mL)
was added, the suspension was filtered, and the solid was washed
with Et2O (3 ꢀ 5 mL) and dried in an oven at 70 °C for 4 h to give
ν(NH) 3218, ν(CtN) 2197, ν(CdN þ CdC) 1615, 1532. ΛM
=
157 Ω-1 cm2 mol-1. Anal. Calcd for C42H44F3IN4O5PdS: C,
50.09; H, 4.40; N, 5.56; S, 3.18. Found: C, 49.81; H, 4.03; N,
5.81; S, 3.36.
2e H2O as a deep yellow solid. Yield: 108.2 mg, 0.12 mmol,
3
74%. Dec pt: 202 °C. 1H NMR (400 MHz, CDCl3, 25 °C, TMS):

5922 Organometallics, Vol. 28, No. 20, 2009
Vicente et al.
δ 1.56 (br, 2 H, H2O), 2.28 (s, 12 H, Me, XyPd), 2.29 (s, 6 H, Me,
Xyq), 5.13 (d, 2 H, CH2, 3JHH=2 Hz), 6.98 (apparent dt, 1 H, H6,
3JHH=8 Hz, 4JHH=1 Hz), 7.14-7.21 (m, 7 H), 7.29-7.37 (m, 3
H), 7.52 (ddd, 1 H, H5, 3JHH=8 Hz, 3JHH=7 Hz, 4JHH=1 Hz),
7.85 (s br, 1 H, NH), 8.17 (dd, 1 H, H7, 3JHH=8 Hz, 4JHH=1
Hz). 13C{1H} NMR(100.8 MHz, CDCl3, 25 °C, TMS): δ 18.5
(Me, Xyq), 18.6 (Me, XyPd), 63.6 (N2CH2), 117.0 (C4), 119.9
(C6), 124.4 (br, ipso-C, XyPd), 124.6 (C2), 128.6 (meta-XyPd),
129.6 (meta-Xyq), 130.3 (para-Xyq), 131.4 (para-XyPd), 133.2
(ortho-Xyq), 134.5 (br, CtN), 136.3 (ortho-XyPd), 136.5 (C7),
138.6 (C5), 142.9 (ipso-Xyq), 144.4 (C3), 204.0 (C1). IR (Nujol,
cm-1): ν(NH) 3214, ν(CtN) 2202, ν(CdN þ CdC) 1615, 1568,
1531. ΛM =157 Ω-1 cm2 mol-1. Anal. Calcd for C35H36F3I-
N4O4PdS: C, 46.76; H, 4.04; N, 6.23; S, 3.57. Found: C, 47.13;
H, 3.68; N, 6.25; S, 3.62.
130.5 (para-Ph), 131.2 (para-XyPd), 131.4 (para-XyPd), 132.6
(ortho-Xyq)], 134.8 (ortho-Xyq), 136.0 (ortho-XyPd), 136.7 [C7 þ
ortho-XyPd), 137.0 (ipso-Ph), 139.3 (C5), 142.0 (ipso-Xyq), 143.1
(C3), 203.1 (C1). IR (Nujol, cm-1): ν(CtN) 2197, ν(CdN þ
CdC) 1615, 1538, 1527. ΛM=143 Ω-1 cm2 mol-1. Anal. Calcd
for C41H40F3IN4O4PdS: C, 50.50; H, 4.13; N, 5.75; S, 3.29.
Found: C, 50.37; H, 3.73; N, 5.71; S, 3.21.
Synthesis
of
trans-[PdI{CdN(Xy)CH(To)NHC6H4-2}-
(CNXy)2]OTf (2h). To a solution of 1 (150 mg, 0.21 mmol) in
CH2Cl2 (10 mL) were successively added ToCHO (To =
C6H4Me-4, 25 μL, 0.21 mmol) and HOTf (18.5 μL, 0.21 mmol).
The resulting suspension was stirred for 2 h and filtered through
a short pad of Celite. The filtrate was concentrated under
vacuum to 1 mL and cooled at 0 °C, and cold Et2O (20 mL,
0 °C) was added. The suspension was filtered, and the solid
collected was recrystallized from CH2Cl2/Et2O and dried first by
suction and then in an oven at 70 °C for 8 h to give 2h as a deep
yellow solid. Yield: 116.4 mg, 0.12 mmol, 57%. Dec pt: 209 °C.
1H NMR (400 MHz, CDCl3, 25 °C, TMS): δ 1.78 (s, 3 H, Me,
Xyq), 2.17 (s, 6 H, Me, XyPd), 2.27 (s, 3 H, Me, To), 2.33 (s, 6 H,
Me, XyPd), 2.34 (s, 3 H, Me, Xyq), 6.32 (d, 1 H, CHTo, 3JHH=4
Hz), 6.90 (dt, 1 H, H6, 3JHH=7 Hz, 4JHH=1 Hz), 6.98 (d, 2 H,
Synthesis of trans-[PdI{CdN(Xy)CH(CHdCH2)NHC6H4-
2}(CNXy)2]OTf (2f). To a solution of 1 (200 mg, 0.28 mmol)
in CH2Cl2 (20 mL) were successively added acrolein (25 μL, 0.34
mmol) and HOTf (25 μL, 0.29 mmol). After 5 h of stirring, the
solution was concentrated under vacuum (1 mL) and cold Et2O
(0 °C, 25 mL) was added. The suspension was filtered and the
solid collected was recrystallized from CH2Cl2 (1 mL) and Et2O
(0 °C, 20 mL) and dried in an oven at 70 °C for 8 h to give 2f as a
lemon-yellow solid. Yield: 203.6 mg, 0.22 mmol, 81%. Mp:
154 °C. 1H NMR (400 MHz, CDCl3, 25 °C, TMS): δ 2.21 (s, 6 H,
Me, XyPd), 2.22 (s, 3 H, Me, Xyq), 2.34 (s, 6 H, Me, XyPd), 2.41
(s, 3 H, Me, Xyq), 5.33 (d, 1 H, CHdCH2, 3JHH=10 Hz), 5.56 (d,
1 H, CHdCH2, 3JHH=17 Hz), 5.67 (dd, 1 H, CHN2, 3JHH=7
3
3
meta-To, JHH=8 Hz), 7.06 (d, 1H, meta-Xyq, JHH=8 Hz),
7.09-7.17 (m, 7 H, meta-XyPd þ ortho-To þ meta-Xyq), 7.20 (d,
1 H, H4, 3JHH=7 Hz), 7.27-7.35 (m, 3 H, para-XyqþPd), 7.53
(dt, 1 H, H5, 3JHH=7 Hz, 4JHH=1 Hz), 8.11 (dd, 1 H, H7, 3JHH
=
7 Hz, 4JHH=1 Hz), 8.25 (d br, 1 H, NH, 3JHH=4 Hz). 13C{1H}
(100.8 MHz, CDCl3, 25 °C, TMS): δ 18.3 (Me, Xyq), 18.4 (Me,
XyPd), 19.0 (Me, XyPd), 19.1 (Me, Xyq), 21.2 (Me, To), 77.2 (C8),
116.6 (C4), 118.8 (C6), 120.5 (q, OTf, 1JCF=320 Hz), 122.0 (C2),
124.4 (ipso-XyPd), 124.6 (ipso-XyPd), 126.9 (ortho-To), 128.5
(meta-XyPd), 128.6 (meta-XyPd), 129.6 (meta-To), 129.7 (meta-
Xyq), 129.8 (para-Xyq), 129.9 (meta-Xyq), 131.2 (para-XyPd),
131.3 (para-XyPd), 132.6 (ortho-Xyq), 134.1 (ipso-To), 134.8
(ortho-Xyq), 135.5 (CtN), 135.6 (CtN), 135.9 (ortho-XyPd),
136.6 (C7), 136.7 (ortho-XyPd), 139.2 (C5), 140.6 (para-To),
143.0 (ipso-Xyq), 143.2 (C3), 202.7 (C1). IR (Nujol, cm-1):
ν(NH) 3212, ν(CtN) 2197, ν(CdN þ CdC) 1615, 1590, 1539.
ΛM=143 Ω-1 cm2 mol-1. Anal. Calcd for C42H40F3IN4O3PdS:
C, 51.94; H, 4.15; N, 5.77; S, 3.30. Found: C, 52.10; H, 4.15; N,
5.70; S, 3.29.
3
3
Hz, JHH =3 Hz), 6.09 (ddd, 1 H, CHdCH2, JHH =17 Hz,
3JHH=10 Hz, 3JHH=7 Hz), 6.95 (ddd, 1 H, H6, 3JHH=8 Hz,
3JHH=1 Hz), 7.06 (d br, 1 H, H4, 3JHH=8 Hz), 7.15 (m, 4 H),
7.24-7.35 (m, 5 H), 7.53 (ddd, 1 H, H5 3JHH=9 Hz, H5, 3JHH=8
Hz, 4JHH=2 Hz), 8.13 (dd, 1 H, H7, 3JHH=8 Hz, 4JHH=1 Hz),
8.21 (d br, 1 H, NH, 3JHH=3 Hz). 13C{1H} NMR (100.8 MHz,
CDCl3, 25 °C, TMS): δ 18.5 (Me, XyPd), 18.7 (Me, Xyq), 18.8
(Me, XyPd), 19.9 (Me, Xyq), 75.9 (C8), 117.2 (C4), 119.5 (C6),
120.6 (OTF, 1JCF=319.7 Hz), 123.4 (CH2), 123.5 (C2), 124.5 (br,
ipso-XyPd), 128.5 (meta-XyPd), 128.7 (meta-XyPd), 129.2
(CHdCH2), 129.5 (meta-Xyq), 129.8 (meta-Xyq), 130.0 (para-
Xyq), 131.3 (para-XyPd), 131.4 (para-XyPd), 133.3 (ortho-Xyq),
134.1 (ortho-Xyq), 136.0 (ortho-XyPd), 136.4 (C7), 136.6 (ortho-
XyPd), 138.8 (C5), 142.6 (ipso-Xyq), 142.9 (C3), 203.0 (C1). IR
(Nujol, cm-1): ν(NH) 3218, ν(CtN) 2199, ν(CdN þ CdC)
1614, 1531. ΛM = 144 Ω-1 cm2 mol-1. Anal. Calcd for
C37H36F3IN4O3PdS: C, 48.99; H, 4.00; N, 6.18; S, 3.53. Found:
Synthesis of trans-[PdI{CdN(Xy)CH{C-Fe(C5H4)(C5H5)}N-
HC6H4-2}(CNXy)2]OTf (2i). To a solution of 1 (200 mg, 0.28
mmol) in CH2Cl2 (20 mL) were successively added ferrocenyl
carboxaldehyde (59.5 mg, 0.28 mmol) and HOTf (24.5 μL, 0.28
mmol). The reaction mixture was stirred for 2.5 h and filtered
through a short pad of Celite. The solution was concentrated
under vacuum (2 mL), and cold Et2O (0 °C, 30 mL) was added.
The resulting suspension was filtered, and the solid collected was
washed with Et2O (3 ꢀ 5 mL) and dried in an oven at 70 °C for
4 h to give 2i as an orange solid. Yield: 235.2 mg, 0.22 mmol,
80%. Dec pt: 191 °C. 1H NMR (400 MHz, CDCl3, 25 °C, TMS):
δ 1.95 (s, 3 H, Me, Xyq), 2.13 (s, 6 H, Me, XyPd), 2.28 (s, 3 H, Me,
Xyq), 2.32 (s, 6 H, Me, XyPd), 3.94 (s br, 1 H, C5H4), 4.00 (s br, 1
H, C5H4), 4.04 (s br, 1 H, C5H4), 4.15 (s br, 1 H, C5H4), 4.38 (s, 5
H, Cp), 5.96 (d, 1 H, CHN2, 3JHH=4 Hz), 6.94 (apparent t, 1 H,
H6, 3JHH=8 Hz), 7.12 (m, 6 H, meta-XyqþPd), 7.29 (m, 3 H, para-
XyqþPd), 7.40 (d, 1 H, H4, 3JHH=8 Hz), 7.59 (apparent dt, 1 H,
H5, 3JHH=8 Hz, 4JHH=1 Hz), 8.07 (dd, 1 H, H7, 3JHH=8 Hz,
4JHH=1 Hz), 8.28 (s br, 1 H, NH). 13C{1H} NMR (100.8 MHz,
CDCl3, 25 °C, TMS): δ 18.3 (Me, XyPd), 18.4 (Me, Xyq), 19.2
(Me, XyPd), 19.8 (Me, Xyq), 65.2 (CH, C5H4), 68.7 (CH, C5H4),
69.5 (CH, C5H4), 69.9 (CH, Cp), 74.6 (C8), 85.2 (C, C5H4), 116.7
(C4), 118.9 (C5), 122.4 (C2), 124.4 (ipso-XyPd), 124.6 (ipso-XyPd),
128.4 (meta-XyPd), 128.5 (meta-XyPd), 129.5 (meta-Xyq), 129.6
(para-Xyq), 129.7 (meta-Xyq), 131.1 (para-XyPd), 131.3 (para-
XyPd), 132.7 (ortho-Xyq), 134.8 (ortho-Xyq), 136.0 (ortho-XyPd),
136.3 (C7), 136.8 (ortho-XyPd), 138.7 (C6), 142.0 (C3), 143.0
(ipso-Xyq), 199.9 (C1). IR (Nujol, cm-1): ν(NH) 3322, ν(CtN)
C, 48.69; H, 3.66; N, 6.08; S, 3.40. Crystals of 2f 0.5Et2O
3
suitable for an X-ray diffraction study were obtained by slow
diffusion of Et2O into a solution of the complex in CHCl3.
Synthesis of trans-[PdI{CdN(Xy)CH(Ph)NHC6H4-2}(CN-
Xy)2]OTf (2g). To a solution of 1 (120 mg, 0.17 mmol) in
CH2Cl2 (10 mL) were successively added benzaldehyde
(17 μL, 0.17 mmol) and HOTf (15 μL, 0.17 mmol). The reaction
mixture was stirred for 2 h and concentrated under vacuum to
dryness, and the residue was stirred with cold Et2O (0 °C,
20 mL). The suspension was filtered, and the filtrate was
concentrated under vacuum (10 mL). Upon cooling at 0 °C, a
suspension formed, which was filtered, and the solid collected
was washed with cold Et2O (0 °C, 3 ꢀ 3 mL) and dried by suction
to give 2g H2O as a lemon-yellow solid. Yield: 120.3 mg, 0.13
3
mmol, 75%). Mp: 119 °C. 1H NMR (300 MHz, CDCl3, 25 °C,
TMS): δ 1.58 (br, 2 H, H2O), 1.74 (s, 3 H, Me, Xyq), 2.17 (s, 6 H,
Me, XyPd), 2.32 (s, 6 H, Me, XyPd), 2.35 (s, 3 H, Me, Xyq), 6.38
(d, 1 H, CHN2, 3JHH=4 Hz), 6.92 (apparent t, 1 H, H6, 3JHH
7.3 Hz), 7.06-7.35 (m, 15 H), 7.55 (apparent dt, 1 H, H5, 3JHH
=
=
7 Hz, 4JHH=1 Hz), 8.11 (d, 1 H, H7, 3JHH=8 Hz), 8.32 (d br, 1 H,
3
NH, JHH=4 Hz). 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C,
TMS): δ 18.3 (Me, Xyq), 18.4 (Me, XyPd), 18.9 (Me, Xyq), 19.0
(Me, XyPd), 77.2 (C8), 116.5 (C4), 118.9 (C6), 121.0 (C2), 127.0
(ortho-Ph), 128.5 (meta-XyPd), 128.6 (meta-XyPd), 129.1 (meta-
Ph), 129.7 (meta-Xyq), 129.8 (para-Xyq), 129.9 (meta-Xyq),
2198, ν(CdN þ CdC) 1614, 1525. ΛM=141 Ω-1 cm2 mol-1
.

Article
Organometallics, Vol. 28, No. 20, 2009 5923
Anal. Calcd for C45H37F3FeIN4O3SPd: C, 50.99; H, 3.52; N,
5.29; S, 3.02. Found: C, 50.86; H, 3.93; N, 5.33; S, 2.79.
suspension was filtered, and the solid collected was dried first by
suction an then in an oven under vacuum at 60 °C for 4 h to give
20c as a yellow solid. Yield: 86.4 mg, 0.0784 mmol, 78%. Dec pt:
190 °C. 1H NMR (300 MHz, CDCl3, 25 °C, TMS): major
isomer, δ 1.52 (s, 6 H, Me, XyPd), 1.96 (s, 3 H, Me, Xyq), 2.23
Synthesis of SP-4-3-[PdI{CdN(Xy)CMe2NHC6H4-2}(CN-
Xy)(PPh3)]OTf (20a). A suspension of 4 (120 mg, 0.12 mmol)
in acetone (10 mL) was stirred for 30 min. The resulting solution
was concentrated under vacuum (1 mL), and Et2O (20 mL) was
added to precipitate a lemon-yellow solid, which was filtered off
(s, 3 H, Me, To), 2.27 (s, 3 H, Me, Xyq), 6.21 (d, 1 H, CH, 3JHH
=
5 Hz), 6.84 (t, 1 H, 3JHH=8 Hz), 6.90-6.96 (m, 3H), 7.05 (d, 2H,
3JHH=8 Hz), 7.10-7.17 (m, 2H), 7.16-7.46 (various m, 20 H),
7.86 (d br, 1H, NH, 3JHH=5 Hz), 8.45 (d, 1H H7, 3JHH=8 Hz);
minor isomer, δ 1.59 (s, 6 H, Me, XyPd), 1.99 (s, 3 H, Me, Xyq),
2.19 (s, 3 H, Me, To), 2.60 (s, 3 H, Me, Xyq), 5.88 (d, 1 H, CH,
3JHH=2 Hz), 7.67 (s br, 1H, NH), 8.35 (d, 1H H7, 3JHH=8 Hz),
the remaining resonances are obscured by those of the major
isomer. 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C, TMS): Major
isomer, δ 17.5 (Me, XyPd), 18.5 (Me, Xyq), 21.2 (Me, To), 22.0
and dried by suction to give 20a H2O. Yield: 107.5 mg, 0.10
3
mmol, 87%. Dec pt: 169 °C. 1H NMR (300 MHz, CDCl3, 25 °C,
TMS): δ 1.46 (s, 6 H, Me, XyPd), 1.51 (s, 3 H, CMe2), 1.63 (br,
H2O), 1.71 (s, 3 H, CMe2), 1.88 (s, 3 H, Me, Xyq), 2.73 (s, 3 H,
Me, Xyq), 6.91 (m, 3 H), 7.14 (m, 2 H), 7.24-7.48 (m, 19 H), 7.86
(s br, 1 H, NH), 8.38 (d, 1 H, H7, 3JHH=8 Hz). 13C{1H} NMR
(100.8 MHz, CDCl3, 25 °C, TMS): δ 17.5 (Me, XyPd), 19.3 (Me,
Xyq), 22.6 (Me, Xyq), 24.5 (Me) 24.9 (Me), 75.6 (d, N2CMe2,
4JCP=5 Hz), 117.5 (C4), 118.3 (C6), 120.7 (q, OTf, 1JCF=320
(Me, Xyq), 76.6 (C8), 116.2 (C4), 117.7 (C6), 120.6 (q, TfO, 1JCF
=
Hz), 124.2 (s br, ipso-XyPd), 127.0 (d, C2, JCP =3 Hz), 128.2
320 Hz), 123.8 (d, C2, JCP =4 Hz), 124.2 (ipso-XyPd), 127.0
3
3
(meta-XyPd), 128.6 (d, meta-PPh3, JCP=11 Hz), 129.1 (meta-
(ortho-To), 128.3 (meta-XyPd), 128.6 (d, meta-PPh3, JCP=11
3
3
Xyq), 130.1 (para-Xyq), 130.5 (d, ipso-PPh3, 1JCP=46 Hz), 130.7
(para-XyPd), 131.3 (d, para-PPh3, 4JCP=2 Hz, 134.1 (d, ortho-
Hz), 129.3 (CH, Xyq or Pd), 129.4 (meta-To þ CH-Xyq or Pd),
130.0 (d, ipso-PPh3, 1JCP=47 Hz), 130.4 (CH, Xyq or Pd), 130.8
PPh3, JCP = 11 Hz), 135.0 (ortho-XyPd), 136.2 (ortho-Xyq),
(CH, Xyq or Pd), 131.3 (d, para-PPh3, JCP =2 Hz), 134.0 (d,
2
4
2
136.6 (C7), 136.7 (ortho-Xyq), 138.1 (C5), 141.0 (d, ipso-Xyq,
4JCP=4 Hz), 142.6 (d, C3, 4JCP=3 Hz), 204.8 (d, C1, JCP=153
Hz). 31P{1H} NMR (162.3 MHz, CDCl3, 25 °C, TMS): δ 14.4.
IR (Nujol, cm-1): ν(NH) 3521, 3462, ν(CtN) 2181, ν(CdN þ
CdC) 1612, 1568, 1526. ΛM=154 Ω-1 cm2 mol-1. Anal. Calcd
for C46H46F3IN3O4PPdS: C, 52.21; H, 4.38; N, 3.97; S, 3.03.
Found: C, 51.81; H, 4.30; N, 3.91; S, 2.84.
ortho-PPh3, JCP = 11 Hz), 135.0 (ortho-XyPd), 135.8 (ortho-
Xyq), 136.1 (ortho-Xyq), 137.4 (C7), 139.6 (C5), 139.9 (para-To),
140.7 (d, ipso-Xyq, 4JCP=4 Hz), 144.8 (d, C3, 4JCP=3 Hz), 207.4
(d, C1, 2JCP=152 Hz); minor isomer, δ=17.8 (Me, XyPd), 20.1
(Me, Xyq), 21.1 (Me, To), 22.7 (Me, Xyq), 116.7 (C4), 119.0 (C6),
127.9 (ortho-To), 128.4 (CH), 129.0 (CH), 129.2 (CH), 130.0
(CH), 130.1 (d, ipso-PPh3, 1JCP=45 Hz), 134.1 (d, ortho-PPh3,
2JCP=12 Hz), 134.4 (C-Xyq or Pd), 135.2 (C-Xy), 135.9 (C-Xy),
137.3 (C7), 138.3 (C5), 140.6 (C-Xy), 139.9 (para-To), 140.7 (d,
ipso-Xyq, 4JCP=4 Hz), 144.8 (d, C3, 4JCP=3 Hz), 207.4 (d, C1,
2JCP=152 Hz), the remaining resonances are obscured by those
of the major isomer. 31P{1H} NMR (121.5 MHz, CDCl3, 25 °C,
TMS): Major isomer, δ 14.6 (br); minor isomer 12.5 (br). IR
(Nujol, cm-1): ν(NH) 3243, ν(CtN) 2190, ν(CdN þ CdC)
1616, 1589, 1537. ΛM =110 Ω-1 cm2 mol-1. Anal. Calcd for
C51H46F3IN3O3PPdS: C, 55.57; H, 4.21; N, 3.81; S, 2.91. Found:
C, 55.17; H, 4.02; N, 3.85; S, 2.63.
Synthesis of SP-4-3-[PdI{CdN(Xy)CH{CH(Me)(Ph)}NH-
C6H4-2}(CNXy)(PPh3)]OTf (20b). To a suspension of 4 (150
mg, 0.15 mmol) in CH2Cl2 (5 mL) was added CH(Me)(Ph)CHO
(21 μL, 0.15 mmol). After 1 h of stirring, the resulting mixture
was filtered though anhydrous MgSO4 and concentrated under
vacuum to 0.5 mL, and cold n-pentane (20 mL, 0 °C) was added.
A suspension formed, which was stirred for 15 min at 0 °C and
filtered. The solid collected was stirred with cold Et2O (0 °C,
5 mL) for 15 min, filtered off, and dried in an oven under vacuum
at 70 °C for 10 h to give 20b H2O as a yellow solid. Yield: 98.5
3
mg, 0.09 mmol, 52%. Mp: 130 °C. 1H NMR (400 MHz, CDCl3,
25 °C, TMS): Major isomer, δ 1.38 (d, 3 H, Me, 3JHH=5 Hz),
1.43 (s, 6 H, Me, XyPd), 1.60 (br, 2 H, H2O), 2.05 (s, 3 H, Me,
Xyq), 2.27 (s, 3 H, Me, Xyq), 5.51 (apparent quint, 1 H, CHMe,
Synthesis of SP-4-4-[PdI{C,N-C(dNHXy)C6H4NH2}CN-
Xy]OTf (3). To a solution of 1 (120 mg, 0.17 mmol) in CH2Cl2
(5 mL) was added HOTf (15 μL, 0,17 mmol). The reaction
mixture was stirred for 5 h, the resulting suspension was filtered,
and the solid collected was washed with CH2Cl2 (3 ꢀ 5 mL) and
dried, first by suction and then in an oven at 70 °C for 4 h to give
3 as a pale yellow solid. Yield: 83.6 mg, 0.11 mmol, 68%. Dec pt:
226 °C. 1H NMR (400 MHz, [D6]acetone, 25 °C, TMS): δ 2.29
(s, 6 H, Me, Xyq), 2.55 (s, 6 H, Me, XyPd), 6.70 (t, 1 H, para-
XyPd, 3JHH=8 Hz), 7.08 (d, 2 H, meta-XyPd, 3JHH=8 Hz), 7.19
(d, 2 H, meta-Xyq, 3JHH=8 Hz), 7.32 (t, 1 H, para-Xyq, 3JHH=8
Hz), 7.56 (br s, 2H, NH2), 7.61 (t, 1 H, H5, 3JHH=8 Hz), 7.82 (d,
1 H, H7, 3JHH=8 Hz), 7.89 (td, 1 H, H6, 3JHH=8 Hz, 4JHH=1
3
3JHH = 7 Hz), 5.59 (apparent t, 1 H, CHN2, JHH = 5 Hz),
6.85-7.03 (various m, 5 H), 7.10-7.45 (various m, 24 H), 7.63 (d
3
3
br, 1 H, NH, JHH =5 Hz), 8.52 (d, 1 H, H7, JHH =8 Hz).
13C{1H} NMR (75 MHz, CDCl3, 25 °C, TMS): major isomer,
δ 17.4 (Me, XyPd), 18.3 (Me, Xyq), 19.1 (CHMePh), 22.7 (Me,
Xyq), 44.6 (CHMePh), 78.1 (d, C8, JCP = 5 Hz), 116.4 (C4),
4
118.1 (C6), 120.6 (q, TfO, JCF = 321 Hz), 124.1 (ipso-XyPd),
1
125.3 (d, C2, 3JCP=4 Hz), 127.2 (para-Ph), 128.1 (meta-XyPd or
ortho- or meta-Ph), 128.2 (meta-XyPd or ortho- or meta-Ph),
128.6 (d, meta-PPh3, 3JCP=11 Hz), 128.8 (ortho- or meta-Ph),
129.0 (CH-Xyq or para-XyPd), 129.8 (CH-Xyq or para-XyPd),
3
Hz) 8.46 (d, 1 H, H4, JHH =8 Hz), 12.53 (br s, 1 H, dNH).
13C{1H} (100.8 MHz, [D6]acetone, 25 °C, TMS): δ 18.6 (Me,
Xyq), 18.9 (Me, XyPd), 122.0 (q, OTf, JCF=321 Hz), 126.0 (C4),
126.8 (ipso-Xyq), 127.6 (C7), 128.9 (meta-Xyq), 129.5 (meta-
XyPd), 129.6 (C5), 130.8 (para-XyPd), 131.0 (para-Xyq), 135.1
(ortho-XyqþPd), 137.8 (C6), 140.5 (C3), 141.5 (ipso-XyPd), 151.6
(C2). IR (Nujol, cm-1): ν(NH) 3211, 3187, 3150, 3075, ν(CtN)
129.9 (d, ipso-PPh3, JCP = 46 Hz), 130.4 (CH-Xyq or para-
1
XyPd), 130.7 (CH-Xyq or para-XyPd), 131.3 (d, para-PPh3,
4JCP = 2 Hz), 134.0 (d, ortho-PPh3, JCP = 11 Hz), 134.8
2
(ortho-Xyq), 134.9 (ortho-XyPd), 135.5 (ortho-Xyq), 137.5 (C7),
139.7 (C5), 140.6 (ipso-Ph), 141.0 (d, ipso-Xyq, JCP = 4 Hz),
4
145.6 (d, C3, 4JCP=3 Hz), 208.7 (d, C1, 2JCP=152 Hz). 31P{1H}
NMR (121.5 MHz, CDCl3, 25 °C, TMS): major isomer, δ 15.1.
IR (Nujol, cm-1): ν(NH) 3223, ν(CtN) 2184, ν(CdN þ CdC)
1614, 1586, 1531. ΛM =111 Ω-1 cm2 mol-1. Anal. Calcd for
C52H50F3IN3O4PPdS2: C, 55.06; H, 4.44; N, 3.70; S, 2.83.
Found: C, 54.91; H, 4.16; N, 3.84; S, 2.73.
Synthesis of SP-4-3-[PdI{CdN(Xy)CH(To)NHC6H4-2}-
(CNXy)(PPh3)]OTf (20c). To a suspension of 4 (100 mg, 0.10
mmol) in CH2Cl2 (10 mL) was added ToCHO (To=C6H4Me-4,
12 μL, 0.1 mmol). The resulting suspension was stirred for 1.5 h
and filtered though Celite. The solution was concentrated under
vacuum (1 mL), and n-pentane (20 mL) was added. The resulting
2207, ν(CdN þ CdC) 1591, 1571. ΛM=144 Ω-1 cm2 mol-1
.
Anal. Calcd for C25H25F3IN3O3PdS: C, 40.69; H, 3.42; N, 5.69;
S, 4.35. Found: C, 40.61; H, 3.46; N, 5.62; S, 4.38. Crystals of
3 CH2Cl2 suitable for an X-ray diffraction study were obtained
3
by slow evaporation of a solution of complex 4 in CH2Cl2.
Synthesis of SP-4-3-[PdI{C(dNHXy)C6H4NH2-2}(CNXy)-
(PPh3)]OTf (4). To a suspension of 3 (167.0 mg, 0.23 mmol) in
CH2Cl2 (20 mL) was added PPh3 (71.2 mg, 0.27 mmol, 20%
excess). After 1.5 h of stirring the resulting solution was con-
centrated under vacuum (1 mL) and Et2O (20 mL) was added.
The resulting suspension was filtered, and the solid collected was
washed with Et2O (3 ꢀ 5 mL) and dried under vacuum for 2 h to

5924 Organometallics, Vol. 28, No. 20, 2009
Vicente et al.
give 4 as a lemon yellow solid. Yield: 170.7 mg, 0.17 mmol, 75%.
TMS): δ 21.5 (Me), 120.3 (C3), 121.6 (CHbpy), 121.9 (CHbpy),
123.5 (C5), 124.2 (C4), 126.4 (CHbpy), 126.5 (CHbpy), 128.5
(ortho-To), 129.1 (meta-To), 134.5 (ipso-To), 137.0 (C1), 138.3
(CHbpy), 138.4 (CHbpy), 139.0 (C6), 140.6 (para-To), 150.3
(CHbpy), 152.9 (CHbpy), 153.0 (Cbpy), 155.6 (Cbpy), 155.9 (C2),
160.4 (CHTo). IR (Nujol, cm-1): ν(CdN þ CdC) 1623, 1602,
1562. Anal. Calcd for C24H20IN3Pd: C, 49.38; H, 3.45; N, 7.20.
Found: C, 49.13; H, 3.36; N, 7.04.
1
Dec pt: 161 °C. H NMR (400 MHz, CD3CN, 25 °C, TMS):
δ 2.13 (s, 6 H, Me, XyPd), 2.15 (s, 3 H, Me, Xyq), 2.43 (s, 3 H, Me,
Xyq), 5.23 (d, 1 H, 3JHH=8 Hz), 5.71 (t, 1 H, 3JHH=8 Hz), 6.07 (s
br, 2 H, NH2), 6.73 (d, 1 H, 3JHH=8 Hz), 6.98-7.03 (m, 1 H),
7.05-7.07 (d, 2 H, 3JHH=8 Hz), 7.10-7.14 (m, 2 H), 7.22-7.26
(m, 2 H), 7.43-7.62 (m, 15 H, PPh3), 11.42 (s br, 1 H, NH).; (400
MHz, CDCl3, -40 °C, TMS): δ 1.92 (s, 6 H, Me, XyPd), 2.14 (s
br, 3 H, Me, Xyq), 2.19 (s br, 3 H, Me, Xyq), 5.12 (d, 1 H, 3JHH=8
Hz), 5.68 (t, 1 H, 3JHH=8 Hz), 5.84 (s br, 2 H, NH2), 6.69 (d, 1 H,
3JHH=8 Hz), 6.84 (s br, 1 H), 6.92 (d, 1 H, 3JHH=8 Hz), 6.96 (d,
5b: Yield: 187.3 mg, 0.27 mmol, 31%. Mp: 181 °C. 1H NMR
(400 MHz, CDCl3, 25 °C, TMS): δ 1.36 (s, 9 H, tBu), 1.40 (s, 9 H,
tBu), 2.30 (s, 3 H, Me), 6.87 (m, 2 H, H6 þ 5), 7.00 (dt, 1 H, H4,
3JHH=7 Hz, 4JHH=1 Hz), 7.08 (d, 2 H, meta-To, 3JHH=8 Hz),
7.32 (dd, 1 H, tbbpy, 3JHH=6 Hz, 4JHH=2 Hz), 7.45 (dd, 1 H,
2 H, 3JHH=8 Hz), 3 H), 7.01-7.06 (m, 2 H), 7.17 (t, 1 H, 3JHH
=
8 Hz), 7.41-7.72 (m, 15 H, PPh3), 12.14 (s br, 1 H, NH). 31P{1H}
NMR (162.3 MHz, CD3CN, 25 °C, TMS): δ 22.3 (br); (162.3
MHz, CHCl3, -40 °C, TMS): δ 23.5 (s). IR (Nujol, cm-1):
ν(NH) 3414, 3328, ν(CtN) 2195, 2181, ν(CdN þ CdC) 1604,
1536, 1531. Anal. Calcd for C43H40F3IN3O3PPdS: C, 51.64; H,
4.03; N, 4.20; S, 3.21. Found: C, 51.50; H, 4.03; N, 4.17;
S, 3.01.
tbbpy, 3JHH=6 Hz, 4JHH=2 Hz), 7.63 (d, 2 H, ortho-To, 3JHH
=
8 Hz), 7.64 (dd, 1 H, H3, 3JHH=7 Hz, 4JHH=1 Hz), 7.73 (d, 1 H,
3
tbbpy, JHH=6 Hz), 7.87-7.88 (m, 2 H, tbbpy), 9.25 (s, 1 H,
CHTo), 9.51 (d, 1 H, tbbpy, 3JHH=6 Hz). 13C{1H} NMR (50.3
t
MHz, CDCl3, 25 °C, TMS): δ 21.5 (Me), 30.2 (Me, Bu), 30.3
t
(Me, Bu), 35.3 (CMe3), 35.4 (CMe3), 117.8 (CHtbbpy), 118.1
Synthesis of [PdI(C6H4NdCHTo-2)(N^N)] [N^N^=bpy (5a),
tbbpy (5b)]. Synthesis of IC6H4NdCHTo-2. To a solution of
IC6H4NH2-2 (2 g, 9.13 mmol) in toluene (30 mL) were added
(CHtbbpy), 121.0 (C6 or 5), 123.4 (C6 or 5), 123.7 (CHtbbpy), 123.8
(CHtbbpy), 124.0 (C4), 128.5 (ortho-CH, To), 129.0 (meta-CH,
To), 134.6 (ipso-C, To), 137.3 (C1), 139.3 (C3), 140.4 (para-C,
To), 149.9 (CHtbbpy), 152.7 (CHtbbpy), 154.0 (Ctbbpy), 155.6
(Ctbbpy), 155.8 (C2), 160.5 (CHTo), 162.8 (Cttbbpy), 162.9
(Ctbbpy). IR (Nujol, cm-1): ν(CdN þ CdC 1614, 1564, 1546).
Anal. Calcd for C32H36IN3Pd: C, 55.22; H, 5.21; N, 6.04.
Found: C, 55.77; H, 4.94; N, 5.84.
˚
ToCHO (To = C6H4Me-4, 1.1 mL, 9.30 mmol) and 4 A
molecular sieves. The reaction mixture was refluxed for 3 h
and filtered. The filtrate was concentrated under vacuum to
dryness to give an oily material, which was dissolved in
n-pentane (15 mL) and cooled at -33 °C. The resulting suspen-
sion was filtered, the solid was washed with cold n-pentane (3 ꢀ
5 mL, -33 °C), and dried by suction to give the title compound
as a pale tan solid. Yield: 2.02 g, 6.30 mmol, 82%. Mp: 53 °C. 1H
NMR (400 MHz, CDCl3, 25 °C, TMS): δ 2.40 (s, 3 H, Me), 6.88
Synthesis of trans-[PdI{C(dNXy)C6H4NdCHTo-2}(CN-
Xy)2] (6). To a solution of 5a (200 mg, 0.34 mmol) in CH2Cl2
(20 mL) was added XyNC (224.7 mg, 1.71 mmol). After 3 h of
stirring, the solution was concentrated under vacuum to ca.
1 mL, Et2O (20 mL) was added, the suspension was filtered, and
the solid collected was recrystallized from CH2Cl2/Et2O (15 mL/
50 mL) and dried first by suction and then in an oven at 70 °C for
(dt, 1 H, H5, 3JHH=8 Hz, 4JHH=1 Hz), 6.96 (dd, 1 H, H3, 3JHH
=
8 Hz, 4JHH=2 Hz), 7.27 (d, 2 H, meta-To, 3JHH=8 Hz), 7.33 (dt,
1H, H4, 3JHH=8 Hz, 4JHH=2 Hz), 7.84 (d, 2 H, ortho-To, 3JHH
=
8 Hz), 7.87 (dd, 1 H, H6, 3JHH=8 Hz, 4JHH=1 Hz), 8.23 (s, 1 H,
CHTo). 13C{1H} NMR (100.8 MHz, CDCl3, 25 °C, TMS): δ
21.7 (Me), 94.8 (C1), 118.4 (C3), 126.8 (C5), 129.1 (ortho-To),
129.3 (C4), 129.5 (meta-To), 133.2 (ipso-To), 138.9 (C6), 142.2
(para-To), 153.1 (C2), 160.7 (CHdN). IR (Nujol): ν(CdN þ
CdC) 1623, 1609. Anal. Calcd for C14H12IN: C, 52.36; H, 3.77;
N, 4.36. Found: C, 52.18; H, 3.71; N, 4.33.
8 h to give 6 H2O as a yellow solid. Yield: 201.9 mg, 0.24 mmol,
3
1
71%. Dec pt: 187 °C. H NMR (400 MHz, CDCl3, -20 °C,
TMS): δ 1.55 (s, 2 H, H2O), 1.95 (s, 12 H, Me, XyPd), 2.09 (s, 6 H,
Me, Xyq), 2.32 (s, 3 H, Me, To), 6.79 (d, 2H, meta-Xyq, 3JHH=7
Hz), 6.85 (t, 1 H, para-Xyq, JHH=7 Hz), 7.00 (d, 4 H, meta-
3
XyPd, 3JHH=8 Hz), 7.07 (d, 1 H, H4, 3JHH=8 Hz), 7.18 (t, 2 H,
3
para-XyPd, JHH=8 Hz), 7.25-7.29 (m, 3 H, H6 þ meta-To),
Synthesis of 5a and 5b. To a suspension of “Pd(dba)2” (for 5a:
750 mg, 1.30 mmol; for 5b: 500 mg, 0.87 mmol) in toluene
(20 mL) under a nitrogen atmosphere were added the appro-
priate bidentate ligand (5a, bpy, 203.7 mg, 1.30 mmol; 5b, tbbpy,
233.4 mg, 0.87 mmol) and IC6H4NdCHTo-2 (for 5a: 418.9 mg,
1.30 mmol; for 5b: 279.2 mg, 0.87 mmol) with a 10 min interval.
The reaction mixture was stirred for 3 (5a) or 1.5 (5b) h, and the
solvent was removed under vacuum to dryness. The residue was
stirred with CH2Cl2 (20 mL), the suspension was filtered
through Celite, and the filtrate was concentrated to ca. 5 mL
(5a) or to dryness (5b). In the case of 5a Et2O (20 mL) was added,
the suspension was filtered, and the solid collected was washed
with Et2O (3 ꢀ 3 mL) and dried by suction to give a yellow solid.
For 5b, cold Et2O (0 °C, 10 mL) and n-hexane (0 °C, 30 mL) were
added to precipitate 5b along with some dba. The crude product
was refluxed in n-hexane (4 ꢀ 20 mL) for 15 min, and the
suspension was filtered while hot. The yellow solid collected was
washed with n-hexane (3 ꢀ 5 mL) and dried by suction to give a
yellow product. 5a: Yield: 533.8 mg, 0.91 mmol, 70%. Mp:
192 °C. 1H NMR (400 MHz, CDCl3, 25 °C, TMS): δ 2.28 (s, 3 H,
Me), 6.87 (dd, 1 H, H6, 3JHH=8 Hz, 4JHH=1 Hz), 6.90 (dt, 1 H,
7.48 (t, 1 H, H5, 3JHH=7 Hz), 7.73 (d, 1 H, H7, 3JHH=7 Hz), 8.23
(d, 2 H, ortho-To, 3JHH=8 Hz), 8.47 (s, 1 H, CHTo). 13C{1H}
NMR (100.8 MHz, CDCl3, -20 °C, TMS): δ 18.4 (Me, XyPd),
18.8 (Me, Xyq), 21.7 (Me, To), 119.3 (C4), 123.0 (para-Xyq),
125.2 (ipso-XyPd), 125.3 (C6), 125.5 (C7), 126.8 (ortho-Xyq),
127.6 (meta-XyPd), 127.7 (meta-Xyq), 129.3 (meta-To), 129.5
(para-XyPd), 130.0 (ortho-To), 130.6 (C5), 132.5 (ipso-To), 135.5
(ortho-XyPd), 139.1 (C2), 142.1 (para-To), 143.1 (CtN), 151.2
(ipso-Xyq), 151.6 (C3), 160.8 (CHTo), 176.4 (C1). IR (Nujol,
cm-1): ν(CtN) 2177, 2147. Anal. Calcd for C41H41IN4OPd: C,
58.69; H, 4.93; N, 6.68. Found: C, 58.82; H, 5.05; N, 6.78.
Crystals of 6 suitable for an X-ray diffraction study were
obtained by the liquid diffusion method from CH2Cl2/Et2O.
Acknowledgment. We thank Dr. A. Guirado and
Dr. R. Andreu for measuring the voltammograms. We
ꢀ
thank Ministerio de Educacion y Ciencia (Spain), FED-
ER (CTQ2007-60808/BQU), and Fundacion Seneca
ꢀ
ꢀ
(04539/GERM/06 and 03059/PI/05) for financial sup-
ꢀ
port. A.J.M.M. thanks Ministerio de Educacion y
Ciencia (Spain) for a FPU grant.
3
4
3
H5, JHH =8 Hz, JHH =1 Hz), 7.00 (dt, 1 H4, JHH =8 Hz,
4JHH=1 Hz), 7.07 (d, 2 H, meta-To, 3JHH=8 Hz), 7.27 (ddd, 1 H,
bpy, 3JHH=7 Hz, 3JHH=5 Hz, 4JHH=1 Hz), 7.40 (ddd, 1 H, bpy,
Supporting Information Available: Cyclic voltammogram of
2i, details on crystal data, data collection, and refinements,
listing of all refined and calculated atomic coordinates, aniso-
tropic thermal parameters, bond lengths and angles, and CIF
files for compounds 2i, 20a, 3, and 6. This material is available
free of charge via the Internet at http://pubs.acs.org.
3JHH=7 Hz, 3JHH=5 Hz, 4JHH=1 Hz), 7.61 (dd, 1 H, H3, 3JHH
=
8 Hz, 4JHH=1 Hz), 7.62 (d, 2 H, ortho-To, 3JHH=8 Hz), 7.81
(dd, 1 H, bpy, 3JHH=5 Hz, 4JHH=1 Hz), 7.89 (m, 2 H, bpy), 8.00
=
(m, 2 H, bpy), 9.05 (s, 1 H, CHTo), 9.55 (dd, 1 H, bpy, 3JHH
5 Hz, 4JHH=1 Hz). 13C{1H} NMR (75.45 MHz, CDCl3, 25 °C,