Study of the reactivity of 2-acetyl-, 2-cyano-, 2-formyl-, and 2-vinylphenyl palladium(II) complexes. Mono- and triinsertion of an isocyanide into the Pd-C bond. A 2-cyanophenyl palladium complex as a ligand

Article abstract of DOI:10.1021/om020380s

A study of the reactivity of the [Pd(C₆H₄X-2)Br(bpy)] (bpy = 2,2′-bipyridine; X = C(O)Me, CN, CHO, CH=CH₂) complexes was presented. The 2-R-arylpalladium(II) complexes reacted with XyNC (Xy = 2,6-dimethylphenyl) to give different mono- and triinserted complexes depending upon the nature of X, the other ligands and the reaction conditions. The crystal structures of the prepared complexes were also reported.

Full text of DOI:10.1021/om020380s

4454
Organometallics 2002, 21, 4454-4467
Stu d y of th e Rea ctivity of 2-Acetyl-, 2-Cya n o-, 2-F or m yl-,
a n d 2-Vin ylp h en yl P a lla d iu m (II) Com p lexes. Mon o- a n d
Tr iin ser tion of a n Isocya n id e in to th e P d -C Bon d . A
2-Cya n op h en yl P a lla d iu m Com p lex a s a Liga n d
J ose´ Vicente,*,† J ose´-Antonio Abad,*,‡ and Elo´ısa Mart´ınez-Viviente
Grupo de Quı´mica Organometa´lica, Departamento de Qu´ımica Inorga´nica, Facultad de
Quı´mica, Universidad de Murcia, Aptdo. 4021, E-30071 Murcia, Spain
Peter G. J ones*,§
Institut fu¨r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
Received May 10, 2002
We have studied the reactivity of the complexes [Pd(C6H4X-2)Br(bpy)] (bpy ) 2,2′-
bipyridine; X ) C(O)Me (1a ), CN (1b), CHO (1c)), [Pd{C6H4CHdCH2-2}(PPh3)(bpy)](TfO)
(TfO ) CF3SO3; 2d ), trans-[Pd(C6H4X-2)Br(PPh3)2] (X ) C(O)Me (3a ), CN (3b), CHdCH2
(3d )), and [Pd(µ-Br)(C6H4X-2)(PPh3)]2(X ) C(O)Me (4a ), CN (4b)). Their reactions with XyNC
(Xy ) 2,6-dimethylphenyl) depend on the nature of X and the other ligands and on the
reaction conditions. The products of these reactions are mono- and triinserted complexes.
Among the former are [Pd{C(dNXy)C6H4X-2}Br(L2)] (L2 ) bpy, X ) C(O)Me (5a ), CN (5b);
L ) CNXy, X ) C(O)Me (6a ), CN (6b), CHdCH2 (6d )) and trans-[Pd{C(dNXy)C6H4CHd
CH2-2}(CNXy)2(PPh3)](TfO) (7d ). The reaction of 1c with XyNC (1:5 molar ratio) gives 10,
a product resulting after substitution of bpy, coordination of two molecules of XyNC,
triinsertion of XyNC, and a cyclization resulting after the attack of the nitrogen of the first
inserted molecule at the carbon atom of the formyl group. The complexes [Pd{κ2C1,N3-C(d
NXy)C(dNXy)C(dNXy)C6H4X-2}Br(CNXy)] (X ) C(O)Me (8a ), CN (8b)) were obtained by
reacting (i) 3a or 3b with XyNC (1:4 molar ratio) or (ii) Pd(dba)2 (dba ) dibenzylideneacetone)
with BrC6H4X-2 and XyNC (1:1:4 molar ratio). When this oxidative addition reaction was
carried out with BrC6H4CHO-2, the resulting product decomposed to give the Pd(I) complex
[Pd2Br2(CNXy)4] (9). Tl(TfO) was reacted with (i) 8a and 8b (1:1 molar ratio) to give the
corresponding triflato complexes 11a and 11b, (ii) 4a (1:2 molar ratio) in the presence of
moisture to give the cyclopalladated aquo complex [Pd{κ2C,O-C6H4{C(O)Me-2}(OH2)(PPh3)]-
(TfO) (12a ), and (iii) 4b (3:1 molar ratio) to give [Pd(C6H4CN-2)(κ2N,N-4b)(PPh3)](TfO) (13b),
in which 4b behaves as a ligand through the two cyano groups. The crystal structures of
5b, 6b, 7d , 8a ,b, 9, 10, 11a ,b, 12a , and 13b have been determined by X-ray diffraction
studies.
In tr od u ction
alized aryl complexes that, after insertion of CO, alk-
enes, or alkynes, give carbo- or heterocycles in which
the ortho group is included.4,5 We have, for example,
reported the synthesis of indenols and indenones by
reacting (o-formylaryl)- or (o-acetylaryl)palladium(II)
complexes with alkynes.6-9 A few examples of insertion
of isocyanides into ortho-functionalized arylpalladium-
(II) complexes leading to heterocyclic compounds have
also been reported.10-12 Thus, we have prepared an
oxoisoindoline or a family of 2-R-amino-isoindolinium
salts by reacting an (o-formylaryl)palladium(II) com-
plex13 or ortho-palladated primary benzylamines,14 re-
spectively, with isocyanides. The interest of this subject
has prompted us to prepare aryl complexes containing
ortho-functionalized aryl groups such as C6H(OMe)3-
2,3,4-X-6 (X)CHO,C(O)Me,CH2OEt,C(O)NHBut),13,15-17
C6H3(CHO)2-2,5,18 C6H4NH2-2,19-21 and C6H4OH-2,22 as
The chemistry of arylpalladium complexes is a topic
of great interest because such compounds participate
in many important palladium-catalyzed organic reac-
tions.1-3 Some of these reactions involve ortho-function-
† E-mail: jvs@um.es. Web: http://www.scc.um.es/gi/gqo/.
‡ E-mail: jaab@um.es.
§ E-mail: jones@xray36.anchem.nat.tu-bs.de.
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10.1021/om020380s CCC: $22.00 © 2002 American Chemical Society
Publication on Web 09/13/2002

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4455
well as cyclopalladated primary and secondary benzyl-
amines.23-25 Some of these complexes have been used
as startingmaterials in reactions with alkynes,7,13,17,24,26-28
carbon monoxide,19,20,22,29 isocyanides,13,21,22,29 and other
unsaturated reagents.30 Recently, we have reported the
synthesis of palladium complexes bearing the aryl
groups C6H4X-2 (X ) CHdCH2, CHO, C(O)Me, CN).8
In this work we wish to present the reactivity of these
arylpalladium complexes, in particular their reactions
with isocyanides. These molecules insert into Pd-C
bonds with various results: monoinsertion to give
(iminoacyl)palladium derivatives,13,21,29,31-33 polyinser-
tion33,34 including polymeric materials,35-37 insertion
with chemical transformation,31,38,39 and insertion with
chemical transformation and depalladation to give
organic products.10-13,39-41 We also report the crystal
structures of most of the prepared complexes, some of
which show interesting features.
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Exp er im en ta l Section
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4456 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
isonitrile XyNC (Xy ) 2,6-dimethylphenyl) and the 2-haloare-
nes were purchased from Fluka. The preparation of complexes
was carried out without precautions against light and moisture
unless otherwise stated.
Method B: from 3b (200 mg, 0.24 mmol) and XyNC (94 mg,
0.72 mmol). Yield: 144 mg, 88%.
Method C: from 4b (60 mg, 0.054 mmol) and XyNC (41 mg,
0.32 mmol). Yield: 38 mg, 52%. Mp: 136-140 °C dec. IR
(cm-1): ν(CtN) 2224, 2208, 2184, ν(CdN) 1612. 1H NMR (300
MHz, CDCl3): δ 8.29 (d, 1H, 3J HH ) 8 Hz), 7.75-7.69 (m, 2H),
Syn th esis of [P d{C(dNXy)C6H4C(O)Me-2}Br (bpy)] (5a).
XyNC (86 mg, 0.65 mmol) was added to a solution of [Pd{C6H4-
[C(O)Me]-2}Br(bpy)] (1a ; 300 mg, 0.65 mmol) in CH2Cl2 (15
cm3). The resulting yellow solution was stirred at room
temperature for 16 h. The solvent was evaporated and Et2O
(20 cm3) added, causing the precipitation of orange 5a . Yield:
325 mg, 84%. Dec pt: 128-130 °C. IR (cm-1): ν(CdO) 1634.
1H NMR (200 MHz, CDCl3): δ 9.11-9.07 (m, 2H), 8.87 (d, 1H,
J HH ) 5 Hz), 8.0-6.8 (m, 12H), 2.56 (s, MeCO, 3H), 2.13 (bs,
Me (Xy), 6H). 13C{1H} NMR (50 MHz, CDCl3): δ 207.6 (Cd
O), 178.0 (CdN), 155.1 (quaternary C), 152.9 (CH), 152.8
(quaternary C), 150.5 (CH), 148.5 (quaternary C), 141.3
(quaternary C), 138.8 (CH), 138.6 (CH), 138.5 (CH), 135.0 (CH),
128.4 (CH), 128.3 (CH), 127.4 (CH), 127.0 (CH), 126.3 (CH),
123.5 (CH), 122.6 (CH), 121.7 (CH), 121.1 (CH), 31.6 (MeCO),
19.9 (2 Me (Xy)). Anal. Calcd for C27H24BrN3OPd: C, 54.71;
H, 4.08; N, 7.09. Found: C, 52.70; H, 4.04; N, 7.07 (see
Discussion).
3
4
7.48 (td, 1H, J HH ) 8 Hz, J HH ) 1 Hz), 7.26-7.20 (m, 2H),
7.1-7.05 (m, C6H3, 4H), 6.92 (br, C6H3, 3H), 2.24 (s, Me, 12H),
2.22 (s, Me, 6H). 13C{1H} NMR (75 MHz, CDCl3): δ 171.3 (Cd
N), 149.6 (quaternary C), 147.8 (quaternary C), 135.8 (6
quaternary C), 134.0 (CH), 132.2 (CH), 131.5 (CH), 130.2 (CH),
128.8 (CH), 128.1 (2 CH), 128.0 (4 CH), 126.5 (2 quaternary
C), 123.7 (CH), 118.7 (quaternary C), 108.8 (quaternary C),
19.0 [2 Me], 18.6 [4 Me]. Anal. Calcd for C34H31BrN4Pd: C,
59.88; H, 4.58; N, 8.22. Found: C, 60.12; H, 4.97; N, 8.58.
Single crystals were grown by slow diffusion of n-hexane into
a solution of 6b in acetone.
Syn th esis of tr a n s-[P d {C(dNXy)C6H4CHdCH2-2}Br -
(CNXy)2] (6d ). This compound was prepared, as described in
method B for 6a , from 3d (200 mg, 0.24 mmol) and XyNC (94
mg, 0.72 mmol). Yield: 123 mg, 75%. This complex darkens
on exposure to daylight. Mp: 90 °C dec. IR (cm-1): ν(CtN)
1
2180, ν(CdN) 1626. H NMR (300 MHz, CDCl3): δ 7.92-7.89
Syn th esis of [P d {C(dNXy)C6H4CN-2}Br (bpy)] (5b). This
was similarly prepared from [Pd{C6H4CN-2}Br(bpy)] (1b; 100
mg, 0.22 mmol) and XyNC (29 mg, 0.22 mmol): orange 5b.
Yield: 54 mg, 43%. Mp: 112-114 °C dec. IR (cm-1): ν(CtN)
(m, 1H), 7.76 (dd, CHdCH2, 1H, 3J HH ) 17 Hz, 3J HH ) 11 Hz),
7.56-7.53 (m, 1H), 7.38-7.30 (m, 2H), 7.24-7.19 (m, 2H),
7.07-7.04 (m, C6H3, 4H), 6.93-6.86 (m, C6H3, 3H), 5.61 (d,
3
CHdCH2 trans to H, 1H, J HH ) 17 Hz), 5.34 (d, CHdCH2 cis
2214. NMR: not sufficiently soluble. Anal. Calcd for C26H21
-
3
to H, 1H, J HH ) 11 Hz), 2.24 (s, Me, 6H), 2.22 (s, Me, 12H).
BrN4Pd: C, 54.24; H, 3.68; N, 9.73. Found: C, 51.67; H, 3.74;
N, 9.37 (see Discussion). Single crystals were grown by slow
diffusion of Et2O into a solution of 5b in CH2Cl2.
13C{1H} NMR: the compound decomposes during the experi-
ment. Anal. Calcd for C35H34BrN3Pd: C, 61.55; H, 5.02; N, 6.15.
Found: C, 60.81; H, 4.96; N, 6.01.
Syn th esis of tr a n s-[P d {C(dNXy)C6H4[C(O)Me]-2}Br -
(CNXy)2] (6a ). Meth od A. XyNC (342 mg, 2.61 mmol) was
added to a solution of 1a (400 mg, 0.87 mmol) in CH2Cl2 (15
cm3). The resulting yellow solution was stirred at room
temperature for 2 h. The solvent was evaporated and Et2O
(20 cm3) added. The resulting mixture was partially evapo-
rated, a precipitate appearing on cooling; the solid was filtered,
washed with cold Et2O, and air-dried, giving yellow 6a . Yield:
547 mg, 90%.
Syn th esis of tr a n s-[P d {C(dNXy)C6H4CHdCH2-2}-
(CNXy)2(P P h 3)](TfO) (7d ). Complex 2d (200 mg, 0.27 mmol)
and XyNC (104 mg, 0.81 mmol) were reacted under nitrogen
for 1 h. The solvent was evaporated in vacuo and Et2O (20
cm3) added. The resulting mixture was partially evaporated,
a precipitate appearing on cooling; the solid was filtered,
washed with cold Et2O, and air-dried, giving yellow 7d .
Yield: 254 mg, 94%. Mp: 110 °C dec. IR (cm-1): ν(CtN) 2196,
2176, ν(CdN) 1618. ΛM (acetone): 136 Ω-1 cm2 mol-1. 1H NMR
(300 MHz, CDCl3): δ 7.7-7.2 (m, 20H), 7.1-7.0 (m, C6H3, 9H),
5.66 (d, CHdCH2 trans to H, 1H, 3J HH ) 17 Hz), 5.35 (d, CHd
Meth od B. 3a (200 mg, 0.24 mmol) and XyNC (94 mg, 0.72
mmol) were mixed in CH2Cl2 (15 cm3) under nitrogen and the
resulting solution evaporated immediately. Et2O (20 cm3) was
added and the mixture partially evaporated to give a precipi-
tate on cooling; the solid was filtered in air and washed with
cold Et2O, giving 6a . Yield: 70 mg, 42%.
3
CH2 cis to H, 1H, J HH ) 11 Hz), 2.18 (s, Me, 6H), 1.74 (s, Me,
12H). 31P{1H} NMR (121 MHz, CDCl3): δ 11.8 (s). Anal. Calcd
for C54H49F3N3O3PPdS: C, 63.94; H, 4.87; N, 4.14; S, 3.16.
Found: C, 63.72; H, 5.10; N, 4.52; S, 2.96. Single crystals were
grown by vapor diffusion of Et2O into a solution of 7d in CH2-
Cl2.
Meth od C. 4a (60 mg, 0.05 mmol) and XyNC (41 mg, 0.32
mmol) were mixed in CH2Cl2 (15 cm3) under nitrogen, and the
resulting solution evaporated immediately. Et2O (20 cm3) was
added and then partially evaporated, a precipitate appearing
on cooling; the solid was filtered in air and washed with cold
Et2O, giving 6a . Yield: 54 mg, 74%. Mp: 104 °C. IR (cm-1):
ν(CtN) 2186, ν(CdO) 1690, 1698, ν(CdN) 1628. 1H NMR (300
Syn t h esis of [P d {K2C1,N3-C(dNXy)C(dNXy)C(dNXy)-
C6H4C(O)Me-2}Br (CNXy)] (8a ). Meth od A. o-Bromoac-
etophenone (0.070 cm3, 0.52 mmol) was added under nitrogen
to a suspension of “Pd(dba)2” (200 mg, 0.35 mmol) and XyNC
(184 mg, 1.4 mmol) in toluene (15 cm3). The suspension was
refluxed for 5 h and then stirred at room temperature for 16
h. After this time the workup is carried out in air. The solvents
were evaporated, the residue was extracted with CH2Cl2, and
the extract was filtered over anhydrous MgSO4. The resulting
red solution was evaporated and the residue triturated with
Et2O (15 cm3). The precipitate was filtered, washed with Et2O
(2 × 5 cm3), and air-dried, giving yellow 8a . Yield: 183 mg,
63%.
3
3
MHz, CDCl3): δ 8.43 (d, 1H, J HH ) 8 Hz), 7.52 (t, 1H, J HH
)
3
8 Hz), 7.42 (t, 1H, J HH ) 8 Hz), 7.31-7.17 (m, 3H), 7.05-7.0
(m, C6H3, 4H), 6.87 (br, C6H3, 3H), 2.55 (s, MeCO, 3H), 2.19
(s, Me (Xy), 12H), 2.17 (s, Me (Xy), 6H). 13C{1H} NMR (50 MHz,
CDCl3): δ 203.8 (CdO), 173.1 (CdN), 149.5 (quaternary C),
143.1 (CtN), 140.4 (quaternary C), 135.9 (6 quaternary C),
132.6 (CH), 130.0 (CH), 129.4 (CH), 128.9 (CH), 128.0 (2 CH),
127.9 (4 CH), 127.3 (2 quaternary C), 125.5 (CH), 123.5 (CH),
31.2 (MeCO), 18.9 (2 Me (Xy)), 18.5 (4 Me (Xy)). Anal. Calcd
for C35H34BrN3OPd: C, 60.14; H, 4.90; N, 6.01. Found: C,
59.87; H, 5.12; N, 6.18.
Meth od B. Complex 3a (60 mg 0.07 mmol) and XyNC (38
mg, 0.29 mmol) were mixed in CH2Cl2 (15 cm3) under nitrogen
and stirred at room temperature for 20 h. The initially yellow
Syn th esis of tr a n s-[P d {Cd(NXy)C6H4CN-2}Br (CNXy)2]
(6b). Procedures similar to those described for 6a were
followed. Method A: from 1b (250 mg, 0.56 mmol) and XyNC
(220 mg, 1.68 mmol); yellow 6b. Yield: 359 mg, 94%.
solution turned red after
a few hours. The solvent was
evaporated and the residue triturated with Et2O (20 cm3),
giving a solid, which was isolated by filtration. This solid was
purified by means of silica gel (70-200 µm) preparative TLC
chromatography using acetone/n-hexane (1:2) as eluant. The
fraction at Rf ) 0.4 was collected and extracted with acetone
to give a solution which was evaporated to dryness. The
(43) Takahashi, Y.; Ito, S.; Sakai, S.; Ishii, Y. J . Chem. Soc., Chem.
Commun. 1970, 1065.

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4457
residue was redissolved in CH2Cl2 (15 cm3), and anhydrous
MgSO4 was added. The resulting suspension was stirred for 1
h and filtered. The solution was evaporated, Et2O was added,
and the precipitate was filtered, washed with Et2O (2 × 5 cm3),
and air-dried to give 8a . Yield: 23 mg, 41%.
3H), 6.65-6.31 (m, 2H), 6.56-6.51 (m, 1H), 2.65 (s, Me, 6H),
2.19 (s, Me, 12H), 1.96 (s, Me, 6H), 1.95 (s, Me, 6H). Anal.
Calcd for C52H50BrN5OPd: C, 65.93; H, 5.32; N, 7.39. Found:
C, 64.49; H, 5.18; N, 7.22 (see Discussion). Single crystals were
grown by slow diffusion of n-pentane into a solution of 10 in
CH2Cl2.
Meth od C. 8a was similarly prepared from 4a (60 mg, 0.05
mmol) and XyNC (52 mg, 0.40 mmol). Yield: 34 mg, 42%. Dec
pt: 243 °C. IR (cm-1): ν(CtN) 2190, ν(CdO) 1676, ν(CdN)
1644. 1H NMR (300 MHz, CDCl3): δ 7.97-7,94 (m, 1H), 7.52-
7.44 (m, 2H), 7.29-7.27 (m, 1H), 7.1-6.75 (m, 10H), 6.35-
6.28 (m, 2H), 2.73 (s, Me, 3H), 2.66 (s, Me, 3H), 2.64 (s, Me,
3H), 2.21 (s, Me, 3H), 2.16 (s, Me (Xy), 6H), 2.08 (s, Me, 3H),
1.90 (s, Me, 3H), 1.09 (s, Me, 3H). 13C{1H} NMR (50 MHz,
CDCl3): δ 197.1 (CdO), 176.3 (CdN), 172.3 (CdN), 169.2 (Cd
N), 151.0 (quaternary C), 147.6 (quaternary C), 143.6 (qua-
ternary C), 135.9 (quaternary C), 134.6 (quaternary C), 132.6
(CH), 132.1 (quaternary C), 131.1 (quaternary C), 130.5 (CH),
129.2 (quaternary C), 129.1 (CH), 128.9 (CH), 128.2 (CH), 127.6
(CH), 127.4 (CH), 127.35 (CH), 127.3 (CH), 126.7 (CH), 126.6
(CH), 126.1 (quaternary C), 123.7 (CH), 123.3 (CH), 121.8
(quaternary C), 27.1 (MeCO), 20.5 (Me (Xy)), 19.9 (Me (Xy)),
18.6 (3 Me (Xy)), 18.4 (2 Me (Xy)), 17.4 (Me (Xy)). Anal. Calcd
for C44H43BrN4OPd: C, 63.66; H, 5.22; N, 6.75. Found: C,
63.36; H, 5.32; N, 6.91. Single crystals were grown by slow
diffusion of n-hexane into a solution of 8a in CH2Cl2.
Syn th esis of [P d {K2-C1,N3-C(dNXy)C(dNXy)C(dNXy)-
C6H4CN-2}Br (CNXy)] (8b). Meth od A. Red 8b was prepared
as described for 8a from “Pd(dba)2” (300 mg, 0.52 mmol), XyNC
(274 mg. 2.09 mmol), and o-bromobenzonitrile (142 mg, 0.78
mmol). Yield: 271 mg, 64%.
Syn t h esis of [P d {K2C1,N3-C(dNXy)C(dNXy)C(dNXy)-
C6H4C(O)Me-2}(OTf)(CNXy)] (11a ). Tl(TfO) (69 mg, 0.19
mmol) was added to a solution of 8a (162 mg, 0.19 mmol) in
CH2Cl2 (15 cm3). The resulting suspension was stirred for 19
h and filtered over Celite and the orange-red filtrate concen-
trated (ca. 2 cm3). Et2O (15 cm3) was added, causing the
precipitation of a yellow solid, which was filtered, washed with
Et2O (2 × 5 cm3), and air-dried to give yellow 11a . Yield: 125
mg, 72%. Dec pt: 165-170 °C. IR (cm-1): ν(CtN) 2202, ν(Cd
1
O), ν(CdN) 1672, 1644. ΛM (acetone): 124 Ω-1 cm2 mol-1. H
NMR (300 MHz, CDCl3): δ 8.00 (dd, 1 H, 3J HH ) 7 Hz, 4J HH
)
1 Hz), 7.56-7.45 (m, 2 H), 7.22-6.80 (m, 10 H), 6.49 (t, 1 H,
3
3J HH ) 7 Hz), 6.24 (br d, 2 H, J HH ) 7 Hz), 2.80 (s, Me, 3H),
2.67 (s, Me, 3H), 2.66 (s, Me, 3H), 2.24 (s, Me, 3H), 2.16 (s, Me
(Xy), 6H), 2.03 (s, Me, 3H), 1.90 (s, Me, 3H), 0.98 (s, Me, 3H).
Anal. Calcd for C45H43F3N4O4PdS: C, 60.10; H, 4.82; N, 6.13;
S, 3.57. Found: C, 60.08; H, 4.90; N, 6.19; S, 3.13. Single
crystals were grown by slow diffusion of n-hexane into a
solution of 11a in chloroform.
Syn t h esis of [P d {K2C1,N3-C(dNXy)C(dNXy)C(dNXy)-
C6H4CN-2}(OTf)(CNXy)] (11b). Red 11b was similarly pre-
pared from 8b (100 mg, 0.12 mmol) and Tl(TfO) (44 mg, 0.12
mmol). Yield: 82 mg, 77%. Dec pt: 255-7 °C. IR (cm-1): ν(Ct
N) 2226, 2210, ν(CdN) 1660, 1634. ΛM (acetone): 112 Ω-1 cm2
mol-1. 1H NMR (300 MHz, CDCl3): δ 7.80-7.78 (m, 1H), 7.56-
Meth od B. Complex 3b (70 mg 0.09 mmol) and XyNC (34
mg, 0.27 mmol) were mixed in CH2Cl2 (15 cm3) under nitrogen
and stirred at room temperature for 20 h. The initially yellow
solution turns red after a few hours. The solvent was evapo-
rated and the residue triturated with Et2O (20 cm3), giving a
red solid which was filtered, washed with Et2O, and air-dried.
Yield: 22 mg, 30%.
3
7.48 (m, 2H), 7.19-6.88 (m, 11H), 6.49 (t, 1H, J HH ) 8 Hz),
3
6.36 (br d, 2H, J HH ) 8 Hz), 2.63 (s, Me, 3H), 2.40 (s, Me,
3H), 2.27 (s, Me, 3H), 2.25 (s, Me, 3H), 2.20 (s, Me, 3H), 2.17
(s, Me, 6H), 1.23 (s, Me, 3H). Anal. Calcd for C44H40F3N5O3-
PdS: C, 59.90; H, 4.57; N, 7.94; S, 3.63. Found: C, 60.11; H,
4.74; N, 8.06; S, 3.20. Single crystals were grown by slow
diffusion of n-hexane into a solution of 11b in CH2Cl2.
Meth od C. 8b was prepared by following the same proce-
dure from 4b (60 mg, 0.05 mmol) and XyNC (52 mg, 0.4 mmol).
Yield: 32 mg, 39%. Dec pt: 148-150 °C. IR (cm-1): ν(CtN)
2224, 2194, ν(CdN) 1642. 1H NMR (300 MHz, CDCl3): δ 7.78-
7.72 (m, 1H), 7.50-7.44 (m, 2H), 7.25-7.17 (m, 1H), 7.12-
Syn th esis of [P d {K2C,O-C6H4[C(O)Me]}(OH2)(P P h 3)]-
(TfO) (12a ). Tl(TfO) (311 mg, 0.44 mmol) was added to a
solution of 4a (250 mg, 0.22 mmol) in CH2Cl2 (15 cm3). The
resulting suspension was stirred for 1 h and then filtered over
Celite. The brown filtrate was concentrated to dryness. Et2O
(15 cm3) was then added, leading to a precipitate that was
filtered, washed with Et2O (2 × 5 cm3), and air-dried, giving
brown 12a . Yield: 220 mg, 77%. Dec pt: 128-130 °C. IR
(cm-1): ν(OH) 3386, ν(CdO) 1582. ΛM (acetone): 123 Ω-1 cm2
mol-1. 1H NMR (300 MHz, CDCl3): δ 7.72-7.66 (m, 6H), 7.53-
3
6.78 (m, 10H), 6.43-6.41 (m, 1H), 6.33 (t, 1H, J HH ) 7 Hz),
2.63 (s, Me, 3H), 2.29 (s, Me, 3H), 2.28 (s, Me, 3H), 2.25 (s,
Me, 3H), 2.15 (s, Me (Xy), 6H), 2.14 (s, Me, 3H), 1.36 (s, Me,
3H). Anal. Calcd for C43H40BrN5Pd: C, 63.51; H, 4.96; N, 8.61.
Found: C, 63.57; H, 4.97; N, 8.53.
Syn t h esis of [P d 2Br 2(CNXy)4] (9). This compound was
prepared, by following the procedure A described for 8a , from
“Pd(dba)2” (300 mg, 0.52 mmol), XyNC (274 mg, 2.09 mmol),
and o-bromobenzaldehyde (0.09 cm3, 0.78 mmol). In this case,
the isolated yellow solid is identified as 9, which had previously
been described.44 Yield: 166 mg, 71%. 1H NMR (300 MHz,
CDCl3): δ 7.25-7.09 (m, 12 H), 2.52 (s, Me, 24H). 13C{1H}
NMR (50 MHz, CDCl3): δ 142.9 (CtN), 135.6 (CMe), 129.8
(CH), 128.0 (CH), 126.4 (CNC), 19.1 (Me). Single crystals were
grown by slow diffusion of n-hexane into a solution of 9 in CH2-
Cl2.
3
3
7.38 (m, 10H), 7.04 (t, 1H, J HH ) 8 Hz), 6.75 (t, 1H, J HH ) 7
3
Hz), 6.33 (t, 1H, J HH ) 8 Hz), 2.73 (s, Me, 3H), 1.82 (s, H2O,
2H). 13C{1H} NMR (50 MHz, CDCl3): δ 216.6 (CdO), 154.62
3
(CPd), 147.9 (CC(O)Me), 138.0 (d, C6 C6H4, J PC ) 10 Hz),
135.0 (d, ortho C’s PPh3, 2J PC ) 12 Hz), 134.7 (CH, C6H4), 132.0
1
(d, ipso C’s PPh3, J PC ) 26 Hz), 131.8 (para C’s PPh3), 128.8
(d, meta C’s PPh3, 3J PC ) 11 Hz), 127.5 (CH, C6H4), 125.3 (CH,
C6H4), 120.0 (q, CF3, J FC ) 318 Hz), 24.8 (Me). 31P{1H} NMR
1
(121 MHz, CDCl3): δ 46.1. Anal. Calcd for C27H24F3O5PPdS:
C, 49.51; H, 3.69; S, 4.90. Found: C, 49.70; H, 3.64; S, 5.27.
Single crystals were grown by slow diffusion of n-hexane into
a solution of 12a in acetone.
Syn th esis of 10. XyNC (440 mg, 3.35 mmol) was added
under nitrogen to a solution of 1c (300 mg, 0.67 mmol) in
acetone (20 cm3). The resulting suspension was stirred for 16
h. The solid thus formed was filtered in air, washed with
acetone (10 × 10 cm3), and dried in air to give deep orange
10. Yield: 214 mg, 34%. Dec pt: 150-152 °C. IR (cm-1): ν(Ct
N) 2178, 2 ν(CdO) 1704, ν(CdN) 1672. 1H NMR (300 MHz,
Syn t h esis of [P d (C6H 4CN-2)(K2N,N-4b )(P P h 3)](TfO)
(13b). Tl(TfO) (64 mg, 0.18 mmol) was added to a solution of
4b (100 mg, 0.09 mmol) in CH2Cl2 (15 cm3). The mixture was
stirred for 40 min and then filtered over Celite. The resulting
yellow solution was evaporated and Et2O (15 cm3) added,
causing the precipitation of a yellow solid, which was filtered
and washed with Et2O (2 × 5 cm3) to give yellow 13b. It was
purified by recrystallization from CH2Cl2/n-hexane. Yield: 79
mg, 76%. Dec pt: 148-150 °C. IR (cm-1): ν(CtN) 2248, 2214
3
3
CDCl3): δ 8.42 (d, 1H, J HH ) 8 Hz), 8.00 (d, 1H, J HH ) 7
3
4
3
Hz), 7.61 (td, 1H, J HH ) 7 Hz, J HH ) 1 Hz), 7.53 (t, 1H, J HH
) 7 Hz), 7.19-7.14 (m, 2H), 7.01-6.93 (m, 7H), 6.77-6.71 (m,
(sh). ΛM (acetone): 117 Ω-1 cm2 mol-1
.
1H NMR (300 MHz,
(44) Duravila, V.; Mingos, D. M. P.; Vilar, R.; White, A. J . P.;
Williams, D. J . J . Organomet. Chem. 2000, 600, 198.
CDCl3): δ 7.65-6.47 (m, 57H), 6.08 (d, 1H, 3J HH ) 8 Hz), 5.68

4458 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
Ta ble 1. Deta ils of Da ta Collection a n d Str u ctu r e Refin em en t for th e Com p lexes 5b, 6b, 7d , a n d
8a ‚1/2CH2Cl2
5b
6b
7d
8a ‚1/2CH2Cl2
formula
cryst habit
cryst size (mm)
λ (Å)
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C
26H21BrN4Pd
C34H31BrN4Pd
pale yellow lath
0.5 × 0.08 × 0.025
0.710 73
monoclinic
P21/c
16.1064(18)
8.1967(10)
24.146(3)
90
C54H49F3N3O3PPdS
yellow prism
0.36 × 0.2 × 0.17
0.710 73
monoclinic
P21
11.9833(8)
14.9230(12)
13.5773(10)
90
C44.5H44BrClN4OPd
orange tablet
0.29 × 0.28 × 0.20
0.710 73
triclinic
P1h
8.1189(6)
11.4137(8)
21.9267(14)
95.774(3)
92.752(3)
98.372(3)
1996.0
yellow needle
0.28 × 0.08 × 0.08
0.710 73
monoclinic
P21/n
9.7317(6)
12.8158(8)
18.5065(12)
90
103.138(3)
90
2247.7
108.072(3)
90
3030.4
98.407(3)
90
2401.9
Z
4
4
2
2
Fcalcd (Mg m-3
Mr
)
1.701
575.78
1144
1.495
681.94
1376
1.403
1014.39
1044
1.452
872.60
890
F(000)
T (°C)
-130
-130
-130
-130
2θmax (deg)
56.5
52.7
60
60
µ(Mo KR) (mm-1
abs cor
)
2.6
SADABS
0.69/0.89
2.0
SADABS
0.52/0.98
0.52
none
2.07
face indexing
0.65/0.77
transmissn
no. of rflns
measd
38 774
5569
0.057
0.025
0.064
291
0
1.03
0.67
35 032
6202
0.092
0.033
0.073
367
90
0.93
0.63
51 700
14 044
0.057
0.029
0.062
634
554
1.00
0.60
39 038
11 633
0.045
0.029
0.073
496
468
1.05
0.69
unique
Rint
Ra (F > 4σ(F))
b
Rw (F2, all rflns)
no. of params
no. of restraints
Sc
max ∆F (e Å-3
)
a
b
2
2
R(F) ) ∑||Fo| - |Fc||/∑|Fo|. Rw(F2) ) [∑{w(Fo - Fc2)2}/∑{w(Fo2)2}]0.5; w-1 ) σ2(Fo2) + (aP)2 + bP, where P ) [Fo + 2Fc2]/3 and a and
b are constants adjusted by the program. c S ) [∑{w(Fo2 - Fc2)2}/(n - p)]0.5, where n is the number of data and p the number of parameters.
(d, 2H, 3J HH ) 8 Hz). 31P{1H} NMR (121 MHz, CDCl3): δ 31.8
and 31.6 (AB system, 4J PP ) 5 Hz); 31.8 and 31.0 (AB system,
Com p ou n d 13b. The anion and the ring C31-N3 are both
disordered over two positions with occupancies of ca. 9:1.
4J PP ) 5 Hz), 28.3 (s), 28.8 (s). Anal. Calcd for C76H57
-
Br2F3N3O3P3Pd3S: C, 53.03; H, 3.34; N, 2.44; S, 1.86. Found:
C, 52.76; H, 3.34; N, 2.48; S, 1.57. Single crystals of the trans
isomer were grown by slow diffusion of n-hexane into a solution
of 13b in CH2Cl2.
Resu lts a n d Discu ssion
Rea ctivity of Com p lexes tow a r d XyNC. We have
studied the reactions of XyNC (Xy ) C6H3Me2-2,6) with
the complexes [Pd(C6H4X-2)Br(bpy)] (X ) C(O)Me (1a ),
CN (1b), CHO (1c)), [Pd(C6H4CHdCH2-2)(PPh3)(bpy)]OTf
(OTf ) CF3SO3-; 2d ) [Pd(C6H4X-2)Br(PPh3)2] (X ) C(O)-
Me (3a ), CN (3b), CHdCH2 (3d )) and [Pd(C6H4X-2)(µ-
Br)(PPh3)]2 (X ) C(O)Me (4a ), CN (4b)) using different
molar ratios and reaction conditions. The obtained
products are the result of mono- or tri-insertion pro-
cesses.
Syn th esis of Mon oin ser ted Com p lexes. When
complexes 1a ,b were reacted with XyNC in a 1:1 molar
ratio, the monoinserted complexes [Pd{C(dNXy)C6H4X-
2}Br(bpy)] (X ) C(O)Me (5a ), CN (5b)) were isolated
(Scheme 1). The carbon analyses of both compounds
deviate somewhat from the expected values (5a , calcd
C 54.71, found C 52.70; 5b, calcd C 54.24, found C
51.67), despite many recrystallizations. Because H and
N analyses were acceptable (Anal. Calcd for 5a : H, 4.08;
N, 7.09. Found: H, 4.04; N, 7.07. Anal. Calcd for 5b:
X-r a y Str u ctu r e Deter m in a tion s. Details of data collec-
tion and refinement are given in Tables 1-3. All compounds
were measured on a Bruker SMART 1000 CCD/LT3 instru-
ment. Structures were refined anisotropically on F2 using the
program SHELXL-97 (G. M. Sheldrick, University of Go¨ttin-
gen). Hydrogen atoms were included using a riding model or
rigid methyl groups. Disordered groups were refined using
appropriate systems of similarity restraints.
Sp ecia l F ea tu r es of Refin em en t. Com p ou n d 7d . The
triflate anion is disordered over two positions with occupancies
of ca. 4:1; the Flack parameter was refined to 0.017(10).
Com p ou n d 8a . The solvent is disordered over two pairs of
positions related by an inversion center.
Com p ou n d 8b. The solvent is disordered over an inversion
center. Compounds 8a ,b are isostructural, although the con-
ventional cell settings lead to different angles.
Com p ou n d 9. The methyl group at C37 converged slowly
and may be rotationally disordered.
Com p ou n d 11a . The solvent is disordered over an inversion
center.
1
H, 3.68; N, 9.73. Found: H, 3.74; N, 9.37), the H and
13C NMR spectra of 5a did not show the presence of
impurities (complex 5b was not sufficiently soluble for
NMR measurements), and the X-ray crystal structure
of 5b was solved (single crystals of 5b were also
analyzed), we believe that the disagreement between
calculated and found carbon analyses are attributable
to a combustion problem of the samples.
Com p ou n d 11b. The triflate is disordered over two posi-
tions with occupancies of ca. 2:1; the site O(1) (coordinated to
Pd) was assumed to be common to both components, but the
Pd-O bond length should be interpreted with caution. The
Flack parameter was refined to -0.027(11).
Com p ou n d 12a . The water H atoms were refined freely,
but with O-H distance restraints.

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4459
Ta ble 2. Deta ils of Da ta Collection a n d Str u ctu r e Refin em en t for th e Com p lexes 8b‚1/2CH2Cl2, 9, 10‚CH2Cl2,
a n d 11a ‚1/2CHCl3
8b‚1/2CH2Cl2
9
10‚CH2Cl2
11a ‚1/2CHCl3
formula
cryst habit
cryst size (mm)
λ (Å)
C43.5H41BrClN5Pd
red prism
0.28 × 0.18 × 0.12
0.710 73
triclinic
P1h
C36H36Br2N4Pd2
yellow tablet
0.30 × 0.16 × 0.05
0.710 73
triclinic
P1h
C53H52BrCl2N5OPd
yellow column
0.24 × 0.22 × 0.18
0.710 73
monoclinic
P21/c
12.3762(8)
20.5074(14)
19.8313(12)
90
C45.5H43.5Cl1.5F3N4O4PdS
yellow hexagonal tablet
0.35 × 0.25 × 0.11
0.710 73
triclinic
P1h
cryst syst
space group
a (Å)
8.2200(6)
11.7082(8)
21.7552(14)
83.784(3)
87.266(3)
70.898(3)
1966.7
9.7060(10)
11.5432(12)
15.7993(16)
94.772(3)
92.936(3)
92.903(3)
1759.0
8.0966(6)
11.7951(8)
23.3677(14)
88.457(3)
88.833(3)
81.515(3)
2206.1
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
106.570(3)
90
4824.5
Z
2
2
4
2
Fcalcd (Mg m-3
Mr
)
1.445
1.694
1.421
1.444
841.22
897.31
1032.21
2112
958.98
F(000)
T (°C)
870
884
982
-130
-130
-130
-100
2θmax (deg)
61
60
56.5
60
µ(Mo KR) (mm-1
abs cor
)
1.6
3.3
1.4
0.62
face indexing
0.70-0.85
SADABS
0.71-0.93
SADABS
0.85-0.96
face indexing
0.84-0.93
transmissn
no. of rflns
measd
43 441
11 961
0.064
0.033
0.080
477
34 438
10 238
0.029
0.024
0.061
405
76 734
11 965
0.051
0.039
0.120
578
0
1.05
1.0
43 217
12 860
0.034
0.038
0.111
554
0
1.04
1.3
unique
Rint
Ra (F > 4σ(F))
b
Rw (F2, all rflns)
no. of params
no. of restraints
Sc
1
0
1.02
0.98
max ∆F (e Å-3
)
0.96
0.54
R(F)) ∑||Fo| - |Fc||/∑|Fo|. Rw(F2) ) [∑{w(Fo - Fc2)2}/∑{w(Fo2)2}]0.5; w-1 ) σ2(Fo2) + (aP)2 + bP, where P ) [Fo + 2Fc2]/3 and a and
a
b
2
2
b are constants adjusted by the program. c S ) [∑{w(Fo2 - Fc2)2}/(n - p)]0.5, where n is the number of data and p the number of parameters.
Sch em e 1
isocyanide into the carbon-palladium bond and the
displacement of bpy by two isocyanide ligands. This kind
of complex is very poorly represented in the literature,
the only examples being those recently prepared by
us.14,21,22 The analogous reaction starting from 1c gave
an intractable mixture. The cationic complex 2d reacts
similarly to give trans-[Pd{C(dNXy)C6H4CHdCH2-2}-
(CNXy)2(PPh3)](TfO) (7d ). Complexes 6a ,b were also
obtained by reacting 3a ,b or 4a ,b with XyNC in a 1:3
molar ratio, but only when reactions were carried out
in CH2Cl2 under nitrogen, and were stopped almost
immediately after mixing the reactants. This method
also allowed the preparation of complex 6d (X ) CHd
CH2) by starting from 3d . 6d darkens on exposure to
sunlight, although the NMR spectra remain the same.
Under aerobic conditions or if the reaction time is
extended, complexes 6a ,b,d were not obtained (see
below). The presence in solution of the displaced PPh3
could be responsible for this behavior; indeed, complex
mixtures were formed when 6a ,b were reacted with
PPh3.
Syn th esis of Tr iin ser ted Com p lexes. Under the
same reaction conditions leading to 6a ,b from 3a ,b or
4a ,b and XyNC, but with a longer reaction time (20 h)
and in a 1:4 molar ratio, the triinserted complexes [Pd-
{κ2C1,N3-C(dNXy)C(dNXy)C(dNXy)C6H4X-2}Br(C-
NXy)] (X ) C(O)Me (8a ), CN (8b)) were isolated
(Scheme 2). A similar reaction from 3d rendered an
intractable complex mixture. It is worth noting that
these reactions also require a nitrogen atmosphere;
otherwise, as occurred in the reaction leading to 6a ,b,
intractable mixtures form. One might believe that
complexes 6 are intermediates in the formation of 8.
However, complexes 6 do not react with XyNC at room
When 1a ,b were reacted with XyNC in a 1:X (X g 3)
molar ratio, the compounds trans-[Pd{C(dNXy)-
C6H4X-2}Br(CNXy)2] (X ) C(O)Me (6a ), CN (6b)) were
obtained (Scheme 1). They resulted from insertion of one

4460 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
Ta ble 3. Deta ils of Da ta Collection a n d Str u ctu r e
Refin em en t for th e Com p lexes 11b, 12a , a n d 13b
Sch em e 2
11b
12a
13b
formula
C
44H40F3N5-
O3PdS
C
27H24F3O5-
PPdS
C
76H57Br2F3-
N3O3P3PdS
cryst habit
red tablet
pale brown
tablet
colorless tablet
cryst size (mm) 0.27 × 0.26 × 0.38 × 0.26 × 0.26 × 0.16 ×
0.18
0.710 73
orthorhombic triclinic
Fdd2
30.842(2)
40.265(3)
13.2880(10)
90
0.10
0.710 73
0.15
0.710 73
monoclinic
P21/c
10.7914(8)
24.809(2)
26.892(2)
90
100.357(3)
90
7082.3
4
λ (Å)
cryst syst
space group
a (Å)
P1h
10.0477(8)
11.0958(11)
12.7645(11)
93.101(3)
107.928(3)
94.628(3)
1344.9
2
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
90
90
16 502
16
Z
Fcalcd (Mg m-3
Mr
F(000)
T (°C)
)
1.421
882.27
7232
-130
60
1.617
654.89
660
-140
60
1.614
1721.24
3416
-130
56.5
2θmax (deg)
µ(Mo KR)
0.56
0.88
2.0
(mm-1
)
abs cor
SADABS
SADABS
face indexing
transmissn
no. of rflns
measd
0.84-0.96
0.81-0.93
0.62-0.78
84 492
12 083
0.051
0.028
0.061
25 576
7811
0.020
0.022
0.061
138 945
17 567
0.098
0.035
0.069
unique
Rint
Ra (F > 4σ(F))
b
Rw (F2, all
rflns)
no. of params
551
352
1
1.07
0.61
913
800
0.95
0.74
no. of restraints 474
Sc
0.99
0.54
max ∆F (e Å-3
)
a
b
2
R(F) ) ∑||Fo| - |Fc||/∑|Fo|. Rw(F2) ) [∑{w(Fo - Fc2)2}/
∑{w(Fo2)2}]0.5; w-1 ) σ2(Fo2) + (aP)2 + bP, where P ) [Fo + 2Fc2]/
2
3 and a and b are constants adjusted by the program. c S )
[∑{w(Fo - Fc2)2}/(n - p)]0.5, where n is the number of data and p
2
the number of parameters.
temperature. This suggests that the presence of PPh3,
as a product of the reaction between 3 or 4 and 4 equiv
of XyNC, could be responsible for the change of reactiv-
ity of complexes 6 toward XyNC. It is possible that free
PPh3 coordinates in complexes 6, forcing the insertion
of the two isocyanide ligands (see Scheme 3). We have
noted above that, in the absence of isocyanide, com-
plexes 6 react with PPh3 to give complex mixtures.
OMe, NO2, F) with XyNC in a 1:6 molar ratio at room
temperature.14
A different behavior was observed in the case of the
o-formylaryl complex 1c, as its reaction with XyNC (1:5
molar ratio) in CH2Cl2 gave intractable mixtures.
However, under nitrogen in acetone, complex 10 pre-
cipitated as a deep orange solid in 34% yield (Scheme
2). The values for carbon in many analyses of 10 were,
like those of 5a ,b, somewhat lower than the calculated
value (calcd C 65.93, found C 64.49), despite many
attempts to purify the complex. Because H and N
analyses were acceptable (calcd H 5.32, N 7.39; found
H 5.18, N 7.22), the 1H NMR spectrum did not show
the presence of impurities, and its X-ray crystal struc-
ture was solved (single crystals of 10 were also ana-
lyzed), we believe that this disagreement between
calculated and found carbon analyses is attributable to
combustion problems of this compound. Workup of the
In addition, the transformation of 6a ,b into 8a ,b can
be achieved by reaction with XyNC in a 1:1 molar ratio
by heating the mixture in a closed tube in 1,2-dichlo-
roethane at 90 °C overnight. 8a ,b could also be prepared
by oxidative addition of the corresponding BrC6H4X-2
arenes to “Pd(dba)2” in the presence of XyNC. When X
was CHdCH2 or CHO, the reactivity was again differ-
ent. In the first case, the mixture decomposed to an ill-
defined mixture, while in the second, the palladium(I)
complex [Pd2Br2(CNXy)4] (9) formed. This complex has
recently been prepared by reacting [Pd2(µ-Br)2(tBu3P)2]
with XyNC.44 Our one-pot synthesis of 9 from “Pd(dba)2”
and BrC6H4CHO-2 is simpler and gives a similar yield.
The previous preparations of complexes of this class
involve comproportionation reactions between [Pd(C-
NR)n] and [PdX2(CNR)2].45-47 We have also prepared 9
by reacting [Pd{C6H3CH2NH2-2-X-5}(µ-Br)]2 (X ) H,
1
mother liquors rendered a mixture for which H NMR
showed the presence of the Pd(I) dimer 9 and another
(45) Otsuka, S.; Tatsuno, Y.; Ataka, K. J . Am. Chem. Soc. 1971, 93,
6705.
(46) Rettig, M. F.; Kirk, E. A.; Maitlis, P. M. J . Organomet. Chem.
1976, 111, 113.
(47) Boehm, J . R.; Balch, A. L. Inorg. Chem. 1977, 16, 778.

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4461
Sch em e 3
F igu r e 1. Thermal ellipsoid plot (50% probability level)
of 5b. Selected bond lengths (Å) and angles (deg): Pd-
C(10) ) 1.988(2), Pd-N(4) ) 2.0655(18), Pd-N(3) ) 2.1441-
(17), Pd-Br ) 2.4259(3), N(1)-C(10) ) 1.265(3), N(1)-
C(21) ) 1.418(3), N(2)-C(17) ) 1.146(3), C(10)-C(11) )
1.499(3); C(10)-Pd-N(4) ) 94.95(8), N(4)-Pd-N(3) )
78.44(7), C(10)-Pd-Br ) 89.15(6), N(3)-Pd-Br ) 97.50-
(5), C(10)-N(1)-C(21) ) 126.33(19), N(1)-C(10)-C(11) )
117.05(18), N(1)-C(10)-Pd ) 128.77(16), C(11)-C(10)-
Pd ) 113.93(14).
Sch em e 5
Sch em e 4
product similar to 10 that decomposed during attempts
at chromatographic separation. The different behavior
of 1c may be due to the electrophilic nature of the carbon
atom of the o-formyl substituent. We believe that the
triinserted complex A (Scheme 4) could be an interme-
diate and that a nucleophilic attack at the formyl carbon
of the nitrogen of the primarily inserted isocyanide could
give the isoindole ring in B. In the case of the synthesis
of 8 this nitrogen attacks at the metal center (Scheme
3). The intermediate B could evolve to C, bearing a
carbon-carbon double bond, which, after an intermo-
lecular proton migration from the OH group to the N of
the second inserted isocyanide, could in turn lead to

4462 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
F igu r e 2. Thermal ellipsoid plot (30% probability level) of 6b. Selected bond lengths (Å) and angles (deg): Pd-C(1) )
1.969(3), Pd-C(2) ) 1.984(3), Pd-C(3) ) 2.035(3), Pd-Br ) 2.5333(5), C(1)-N(1) ) 1.146(4), C(2)-N(2) ) 1.146(4), C(3)-
N(4) ) 1.267(4), C(3)-C(31) ) 1.477(4), C(11)-N(1) ) 1.407(4), C(21)-N(2) ) 1.405(4), C(37)-N(3) ) 1.140(4), C(41)-
N(4) ) 1.426(4); C(1)-Pd-C(3) ) 90.36(12), C(2)-Pd-C(3) ) 88.14(12), C(1)-Pd-Br ) 89.53(8), C(2)-Pd-Br ) 91.98(8),
N(1)-C(1)-Pd ) 176.3(3), N(2)-C(2)-Pd ) 178.0(3), N(4)-C(3)-C(31) ) 118.0(3), N(4)-C(3)-Pd ) 126.2(2), C(31)-
C(3)-Pd ) 115.8(2), C(1)-N(1)-C(11) ) 178.2(3), C(2)-N(2)-C(21) ) 172.1(3), C(3)-N(4)-C(41) ) 121.9(3).
complex 10. There is no precedent for this type of
structure, which has been confirmed by an X-ray
structure analysis. We have reported the synthesis of a
highly functionalized ketenimine resulting after a di-
insertion of XyNC in an (o-formylaryl)palladium com-
plex. Its structure can be viewed as the result of a
substitution of the [Pd]C{C(dNXy)C(NHXy)} group in
10 (see Scheme 4) by CdNXy.13 The formation of such
a ketenimine is also the result of the attack of the
nitrogen of the primarily inserted isocyanide at the
formyl carbon.
Rea ctivity of Com p lexes tow a r d Tl(TfO). The
ortho groups in the above complexes are able to coor-
dinate intramolecularly to give cyclometalated com-
plexes or intermolecularly to give polynuclear species.
To force such coordination, we have carried out some
reactions with Tl(TfO). Another objective of these reac-
F igu r e 3. Thermal ellipsoid plot (30% probability level)
of the cation of 7d . Selected bond lengths (Å) and angles
(deg): Pd-C(1) ) 1.9875(18), Pd-C(2) ) 1.9893(17), Pd-
C(3) ) 2.0726(18), Pd-P ) 2.3991(5), C(1)-N(1) ) 1.151-
(2), C(2)-N(2) ) 1.151(2), C(3)-N(3) ) 1.259(2), C(3)-
C(31) ) 1.508(2), N(1)-C(11) ) 1.405(2), N(2)-C(21) )
1.414(2), N(3)-C(41) ) 1.414(2), S-O(1) ) 1.420(3), S-O(2)
) 1.435(3), S-O(3) ) 1.438(2); C(1)-Pd-C(3) ) 87.40(7),
C(2)-Pd-C(3) ) 88.57(7), C(1)-Pd-P ) 91.10(5), C(2)-
Pd-P ) 93.53(5), N(1)-C(1)-Pd ) 173.47(15), N(2)-C(2)-
Pd ) 178.16(16), N(3)-C(3)-C(31) ) 117.38(17), N(3)-
C(3)-Pd ) 126.56(14), C(31)-C(3)-Pd ) 115.97(12), C(1)-
N(1)-C(11) ) 171.89(18), C(2)-N(2)-C(21) ) 172.96(18),
C(3)-N(3)-C(41) ) 126.64(16), O(1)-S-O(2) ) 113.9(3),
O(1)-S-O(3) ) 116.1(2), O(2)-S-O(3) ) 114.18(17).
tions was to induce decomposition processes leading to
N-heterocyclic compounds. However, whereas the first
objective was attained in a few cases, no decompositions
were observed. Thus, complexes 8a ,b react with Tl(TfO)
to give complexes 11a ,b, resulting from substitution of
the bromo ligand by triflate (Scheme 1). We have also
studied the reactions of complexes 1, 3, and 4 with Tl-
(TfO). Although, most of our attempts gave intractable
mixtures, positive results were obtained in two cases.
Thus, the reaction of 4a with Tl(TfO) gives a precipitate
of TlBr and the cyclopalladated aquo complex [Pd-
{κ2C,O-C6H4[C(O)Me]}(OH2)(PPh3)](TfO) (12a ) (Scheme
5). The reaction is regioselective, since only the isomer
with the aquo ligand trans to carbon was obtained (see
discussion below).
in agreement with its 31P NMR spectrum. However, only
single crystals of the trans isomer could be obtained (see
below).
Sp ectr oscop ic P r op er ties of Com p lexes. The ν-
(CtN) absorptions of complexes having coordinated
XyNC and/or the aryl ligand C6H4CN-2 appear at 2248-
2176 cm-1 (see Experimental Section). The assignments
are difficult when both ligands are present in the same
complex. However, by comparison between appropriate
examples, it is possible to assign tentatively the lower
The reaction of 4b with Tl(TfO) led to the partial
elimination of the bromo ligand (even if carried out with
a 1:2 molar ratio) and the formation of the unusual
trinuclear complex [Pd(C6H4CN-2)(κ2N,N-4b)(PPh3)]-
(TfO) (13b). Its structure can be considered as the result
of the coordination of 4b as a chelating ligand, through
the nitrogen atoms of the CN substituents, to a Pd(C6H4-
CN-2)PPh3 moiety. Two isomers, with the 4b ligand in
a cis or trans geometry, seem to be present in solution,

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4463
F igu r e 4. Thermal ellipsoid plot (30% probability level,
solvent omitted) of 8a ‚1/2CH2Cl2. Selected bond lengths (Å)
and angles (deg): Pd-C(50) ) 1.9327(16), Pd-C(40) )
1.9936(15), Pd-N(2) ) 2.1243(12), Pd-Br ) 2.5390(2),
N(2)-C(10) ) 1.2908(19), N(2)-C(21) ) 1.4491(18), N(3)-
C(30) ) 1.2704(19), N(3)-C(31) ) 1.4198(19), N(4)-C(40)
) 1.2624(19), N(4)-C(41) ) 1.415(2), N(5)-C(50) ) 1.150-
(2), N(5)-C(51) ) 1.3949(19), O-C(17) ) 1.217(2), C(10)-
C(11) ) 1.489(2), C(10)-C(30) ) 1.496(2), C(30)-C(40) )
1.492(2); C(50)-Pd-C(40) ) 90.54(6), C(40)-Pd-N(2) )
80.72(5), C(50)-Pd-Br ) 89.47(4), N(2)-Pd-Br ) 100.23-
(3), C(10)-N(2)-C(21) ) 120.62(13), C(10)-N(2)-Pd )
113.57(10), C(21)-N(2)-Pd ) 125.28(10), C(30)-N(3)-
C(31) ) 121.78(13), C(40)-N(4)-C(41) ) 122.88(13), C(50)-
N(5)-C(51) ) 177.04(16), N(2)-C(10)-C(11) ) 128.14(14),
N(2)-C(10)-C(30) ) 112.90(13), C(11)-C(10)-C(30) )
118.17(13), O-C(17)-C(12) ) 120.44(15), O-C(17)-C(18)
) 120.11(17), C(12)-C(17)-C(18) ) 119.45(16), N(3)-
C(30)-C(40) ) 128.68(13), N(3)-C(30)-C(10) ) 117.12(13),
C(40)-C(30)-C(10) ) 112.92(12), N(4)-C(40)-C(30) )
120.27(13), N(4)-C(40)-Pd ) 134.44(11), C(30)-C(40)-
Pd ) 105.01(10), N(5)-C(50)-Pd ) 172.59(14).
F igu r e 5. Thermal ellipsoid plot (30% probability level,
solvent omitted) of 8b‚1/2CH2Cl2. Selected bond lengths (Å)
and angles (deg): Pd-C(50) ) 1.9386(19), Pd-C(40) )
2.0037(18), Pd-N(2) ) 2.1174(14), Pd-Br ) 2.5282(3),
C(10)-N(2) ) 1.288(2), C(10)-C(11) ) 1.485(2), C(10)-
C(30) ) 1.496(2), C(17)-N(1) ) 1.142(3), C(21)-N(2) )
1.450(2), C(30)-N(3) ) 1.265(2), C(30)-C(40) ) 1.504(2),
C(31)-N(3) ) 1.423(2), C(40)-N(4) ) 1.258(2), C(41)-N(4)
) 1.422(2), C(50)-N(5) ) 1.149(2), C(51)-N(5) ) 1.399-
(2); C(50)-Pd-C(40) ) 91.17(7), C(40)-Pd-N(2) ) 80.71-
(6), C(50)-Pd-Br ) 90.38(5), N(2)-Pd-Br ) 97.89(4),
N(2)-C(10)-C(11) ) 127.23(16), N(2)-C(10)-C(30) )
113.21(15), C(11)-C(10)-C(30) ) 119.55(15), N(1)-C(17)-
C(12) ) 178.4(3), N(3)-C(30)-C(10) ) 117.68(15), N(3)-
C(30)-C(40) ) 129.30(16), C(10)-C(30)-C(40) ) 112.04-
(15), N(4)-C(40)-C(30) ) 118.44(15), N(4)-C(40)-Pd )
136.71(13), C(30)-C(40)-Pd ) 104.55(11), N(5)-C(50)-
Pd ) 178.27(17), C(10)-N(2)-C(21) ) 120.54(14), C(10)-
N(2)-Pd ) 113.77(11), C(21)-N(2)-Pd ) 125.54(11), C(30)-
N(3)-C(31) ) 121.28(15), C(40)-N(4)-C(41) ) 125.29(15),
C(50)-N(5)-C(51) ) 175.30(19).
frequencies to the coordinated isocyanides and the
higher ones to the nitrile substituents. Thus, the
coordinated XyNC ligands appear within the range
2176-2210 cm-1 and the nitrile groups at 2214-2226
cm-1. In the case of complex 13b, in which two nitrile
substituents are coordinated to a palladium atom, a
shift to a higher frequency (2248 cm-1) is observed; a
shoulder band at 2214 cm-1 is assigned to the uncoor-
dinated CN. The ν(CdO) absorptions of the acetylaryl
complexes 5a , 6a , 8a , and 11a appear at 1630-1700
cm-1. In the case of the cyclopalladated complex 12a
this band shifts to lower frequency (1582 cm-1) because
of the coordination of the carbonyl oxygen to the
palladium atom, as previously observed in related C,O
palladacycles.8,13,15,16
another one integrated to two methyls; this suggests a
steric hindrance of the rotation of three of the xylyl
groups, while the fourth one rotates freely.
The 31P NMR spectrum of 13b shows two sets of
signals, each corresponding to an AB system and a
singlet. We believe that this is due to the existence of
13b in solution as a mixture of complexes derived from
cis-4b and trans-4b.
Str u ctu r e of Com p lexes. We have shown that the
following pairs of ligands have increasing phobia of
being mutually trans in palladium(II) complexes: X-
donor/Y-donor (X, Y ) halogen, N-donor, P-donor) ≈
C-donor/X-donor (X ) halogen, N-donor) < C-donor/P-
donor < C-donor/C-donor. The antisymbiotic effect48
does not explain these differences. This effect assumes
that two soft ligands in mutually trans positions will
have a destabilizing effect on each other when attached
to a class b metal such as Pd(II). However, Pd(II)
complexes with pairs of soft ligands such as PR3/PR3,
Br/Br, and Br/PR3 in mutually trans positions are very
stable, while others, also with soft ligands, such as
C-donor/P-donor and C-donor/C-donor, are not. In ad-
1
The H NMR spectra of complexes 6 and 7d show one
singlet for the two methyl groups of the inserted XyNC
and another one for the four methyls of the two
equivalent coordinated isocyanides. In 5a , the methyl
substituents of the inserted XyNC give a broad signal,
suggesting a slow rotation of the Xy group. In complex
10 the presence of four methyl singlets, one of them with
an integrated intensity twice that of the others, indi-
cates also a trans geometry and free rotation of the Xy
groups. In contrast, complexes 8 and 11 show six
singlets, each corresponding to a methyl group, and
(48) Pearson, R. G. Inorg. Chem. 1973, 12, 712.

4464 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
F igu r e 7. Thermal ellipsoid plot (30% probability level,
solvent omitted) of 10‚CH2Cl2. Hydrogen atoms, except that
attached to N(2), have been omitted for clarity. Selected
bond lengths (Å) and angles (deg): Pd-C(50) ) 1.986(3),
Pd-C(60) ) 1.999(3), Pd-C(10) ) 2.031(3), Pd-Br )
2.5288(4), O-C(37) ) 1.220(3), N(1)-C(10) ) 1.267(3),
N(1)-C(11) ) 1.413(4), N(2)-C(20) ) 1.378(3), N(2)-C(21)
) 1.426(3), N(4)-C(37) ) 1.384(4), N(4)-C(40) ) 1.439-
(3), N(4)-C(41) ) 1.440(3), N(5)-C(50) ) 1.150(4), N(5)-
C(51) ) 1.410(3), N(6)-C(60) ) 1.151(4), N(6)-C(61) )
1.408(4), C(10)-C(20) ) 1.503(4), C(20)-C(40) ) 1.368(4),
C(31)-C(40) ) 1.476(4), C(32)-C(37) ) 1.459(4); C(50)-
Pd-C(10) ) 93.09(11), C(60)-Pd-C(10) ) 90.64(11), C(50)-
Pd-Br ) 88.25(9), C(60)-Pd-Br ) 88.30(8), C(10)-N(1)-
C(11) ) 127.9(3), C(20)-N(2)-C(21) ) 125.8(2), C(37)-
N(4)-C(40) ) 112.3(2), C(37)-N(4)-C(41) ) 119.7(2),
C(40)-N(4)-C(41) ) 127.9(2), C(50)-N(5)-C(51) ) 174.5-
(3), C(60)-N(6)-C(61) ) 173.7(3), N(1)-C(10)-C(20) )
119.3(3), N(1)-C(10)-Pd ) 127.7(2), C(20)-C(10)-Pd )
112.93(17), O-C(37)-N(4) ) 124.7(3), O-C(37)-C(32) )
129.8(3), N(4)-C(37)-C(32) ) 105.5(2), C(20)-C(40)-N(4)
) 123.6(2), C(20)-C(40)-C(31) ) 131.4(3), N(4)-C(40)-
C(31) ) 104.7(2), N(5)-C(50)-Pd ) 169.3(3), N(6)-C(60)-
Pd ) 171.9(3).
F igu r e 6. Thermal ellipsoid plot (50% probability level)
of 9. Selected bond lengths (Å) and angles (deg): Pd(1)-
C(20) ) 1.957(2), Pd(1)-C(10) ) 1.966(2), Pd(1)-Br(1) )
2.5193(3), Pd(1)-Pd(2) ) 2.5269(3), Pd(2)-C(40) ) 1.956-
(2), Pd(2)-C(30) ) 1.963(2), Pd(2)-Br(2) ) 2.5294(3),
N(1)-C(10) ) 1.153(2), N(1)-C(11) ) 1.410(2), N(2)-C(20)
) 1.151(2), N(2)-C(21) ) 1.408(2), N(3)-C(30) ) 1.155-
(2), N(3)-C(31) ) 1.405(2), N(4)-C(40) ) 1.161(2), N(4)-
C(41) ) 1.406(2); C(20)-Pd(1)-C(10) ) 170.78(8), C(40)-
Pd(2)-C(30) ) 170.07(8), C(20)-Pd(1)-Br(1) ) 97.02(6),
C(10)-Pd(1)-Br(1) ) 91.89(6), C(20)-Pd(1)-Pd(2) ) 80.62-
(6), C(10)-Pd(1)-Pd(2) ) 90.36(6), C(40)-Pd(2)-Pd(1) )
83.23(6), C(30)-Pd(2)-Pd(1) ) 87.33(6), C(40)-Pd(2)-Br-
(2) ) 98.41(6), C(30)-Pd(2)-Br(2) ) 91.12(6), C(10)-N(1)-
C(11) ) 171.8(2), C(20)-N(2)-C(21) ) 172.3(2), C(30)-
N(3)-C(31) ) 178.8(2), C(40)-N(4)-C(41) ) 172.9(2),
N(1)-C(10)-Pd(1) ) 173.41(18), N(2)-C(20)-Pd(1) )
177.30(18), N(3)-C(30)-Pd(2) ) 174.24(18), N(4)-C(40)-
Pd(2) ) 178.89(18).
dition, this destabilizing effect depends on the class b
metal involved. It is generally less marked for Pt(II)
than for Pd(II). We have named this destabilizing effect
transphobia (T), a term that has already been accepted
by many authors.19-21,49-54 When the product of a
reaction contains a pair of ligands with high T in trans
positions, one of which is generally a C-donor, a further
reaction such as an X-Y coupling process (X ) C, Y )
C, N, O, P),2,20,49,55,56 an insertion of atmospheric O2 into
the C-Pd bond,19,20 or an intramolecular redox reaction
usually takes place.57,58 In contrast, if the two pairs of
trans ligands have low T, the reaction product tends to
be stable. Although the observation of the geometries
of stable complexes cannot always provide information
on the degree of T of their possible pairs of trans ligands,
we think that looking at the geometry of a family of
complexes would allow more members to be placed in
the scale of T. Thus, the trans geometry of complexes
6a ,b,d , 7d , and 10 could be a result of the relationship
T[XyNC/CNXy] < T[XyNC/C(dNXy)R] (R ) C6H4X-2,
X ) C(O)Me, CN, CHdCH2). We have recently reported
the complexes [PdX{C(dE)R}(CNR′)2]n+ (X ) Br, I,
PPh3; E ) O, NXy, NtBu; R ) C6H3Y-2-Z-5 (Y ) NH2,
OH, OC(O)Me; Z ) H, NO2); n ) 0, 1),21,22 which also
have a trans geometry. However, the differing steric
requirements of the ligands involved could also play a
significant role in determining the geometry of these
complexes. We have reported that two complexes analo-
gous to 7d , trans-[Pd{C(dNtBu)C6H4NH2-2-X-5}(CNt-
Bu)2(PPh3)](TfO) (X ) H, NO2), decompose to give the
(49) Vicente, J .; Arcas, A.; Bautista, D.; Tiripicchio, A.; Tiripicchio-
Camellini, M. New J . Chem. 1996, 20, 345.
(50) Vicente, J .; Arcas, A.; Bautista, D.; J ones, P. G. Organometallics
1997, 16, 2127.
(51) Vicente, J .; Arcas, A.; Ferna´ndez-Herna´ndez, J .; Bautista, D.
Organometallics 2001, 20, 2767.
(52) Vicente, J .; Arcas, A.; Blasco, M. A.; Lozano, J .; Ram´ırez de
Arellano, M. C. Organometallics 1998, 17, 5374.
(53) Vicente, J .; Chicote, M. T.; Rubio, C.; Ram´ırez de Arellano, M.
C.; J ones, P. G. Organometallics 1999, 18, 2750.
(54) (a) Lohner, P.; Pfeffer, M.; Fischer, J . J . Organomet. Chem.
2000, 607, 12. (b) Albert, J .; Cadena, J . M.; Delgado, S.; Granell, J . J .
Organomet. Chem. 2000, 603, 235. (c) Albert, J .; Cadena, J . M.; Granell,
J . R.; Solans, X.; Fontbardia, M. Tetrahedron: Asymmetry 2000, 11,
1943. (d) Albert, J .; Bosque, R.; Cadena, J . M.; Granell, J . R.; Muller,
G.; Ordinas, J . I. Tetrahedron: Asymmetry. 2000, 11, 3335. (e) Albert,
J .; Bosque, R.; Cadena, J . M.; Delgado, S.; Granell, J . J . Organomet.
Chem. 2001, 634, 83. (f) Carbayo, A.; Cuevas, J . Y.; Garcia-Herbosa,
G.; Garcia-Granda, S.; Miguel, D. Eur. J . Inorg. Chem. 2001, 2361. (g)
Fernandez, S.; Navarro, R.; Urriolabeitia, E. P. J . Organomet. Chem.
2000, 602, 151. (h) Fernandez-Rivas, C.; Cardenas, D. J .; Martin-
Matute, B.; Monge, A.; Gutierrez-Puebla, E.; Echavarren, A. M.
Organometallics 2001, 20, 2998. (i) J alil, M. A.; Fujinami, S.; Nish-
ikawa, H. J . Chem. Soc., Dalton Trans. 2001, 1091. (j) Larraz, C.;
Navarro, R.; Urriolabeitia, E. P. New J . Chem. 2000, 24, 623.
(55) Stille, J . K. Angew. Chem., Int. Ed. Engl. 1986, 25, 504.
(56) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
(57) Rabin, O.; Vigalok, A.; Milstein, D. Chem. Eur. J . 2000, 6, 454.
(58) Vicente, J .; Abad, J . A.; Herna´ndez-Mata, F. S.; J ones, P. G. J .
Am. Chem. Soc., in press.

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4465
F igu r e 9. Thermal ellipsoid plot (30% probability level)
of 11b. Only one position of the disordered triflate is shown.
Selected bond lengths (Å) and angles (deg): Pd-C(50) )
1.9619(19), Pd-C(40) ) 1.9681(18), Pd-N(2) ) 2.1086(15),
Pd-O(1) ) 2.1894(15), N(1)-C(17) ) 1.144(3), N(2)-C(10)
) 1.291(2), N(2)-C(21) ) 1.449(2), N(3)-C(30) ) 1.268-
(2), N(3)-C(31) ) 1.438(2), N(4)-C(40) ) 1.255(2), N(4)-
C(41) ) 1.421(2), N(5)-C(50) ) 1.154(2), N(5)-C(51) )
1.407(2), C(10)-C(11) ) 1.483(2), C(10)-C(30) ) 1.495(3),
C(12)-C(17) ) 1.447(3), C(30)-C(40) ) 1.513(2), O(1)-S
) 1.4381(17), S-O(3) ) 1.431(3), S-O(2) ) 1.435(2);
C(50)-Pd-C(40) ) 90.62(7), C(40)-Pd-N(2) ) 81.01(7),
C(50)-Pd-O(1) ) 95.32(7), N(2)-Pd-O(1) ) 93.81(6),
C(10)-N(2)-C(21) ) 122.84(16), C(10)-N(2)-Pd ) 113.93-
(12), C(21)-N(2)-Pd ) 123.18(12), C(30)-N(3)-C(31) )
120.53(15), C(40)-N(4)-C(41) ) 125.34(16), C(50)-N(5)-
C(51) ) 176.12(19), N(2)-C(10)-C(11) ) 127.25(17), N(2)-
C(10)-C(30) ) 114.12(16), C(11)-C(10)-C(30) ) 118.62-
(15), N(3)-C(30)-C(10) ) 119.35(16), N(3)-C(30)-C(40)
) 128.99(17), C(10)-C(30)-C(40) ) 111.39(15), N(4)-
C(40)-C(30) ) 118.56(16), N(4)-C(40)-Pd ) 133.29(14),
C(30)-C(40)-Pd ) 107.18(12), N(5)-C(50)-Pd ) 173.43-
(16), O(3)-S-O(2) ) 118.3(2), O(3)-S-O(1) ) 114.46(19),
O(2)-S-O(1) ) 110.98(13).
F igu r e 8. Thermal ellipsoid plot (30% probability level,
solvent omitted) of 11a ‚1/2CHCl3. Selected bond lengths (Å)
and angles (deg): Pd-C(50) ) 1.959(2), Pd-C(40) )
1.9772(19), Pd-N(2) ) 2.0935(16), Pd-O(2) ) 2.1678(15),
N(2)-C(10) ) 1.283(3), N(2)-C(21) ) 1.444(2), N(3)-C(30)
) 1.268(3), N(3)-C(31) ) 1.425(3), N(4)-C(40) ) 1.252-
(2), N(4)-C(41) ) 1.420(3), N(5)-C(50) ) 1.147(3), N(5)-
C(51) ) 1.398(3), O(1)-C(17) ) 1.221(3), C(10)-C(11) )
1.491(3), C(10)-C(30) ) 1.496(3), C(12)-C(17) ) 1.486(3),
C(30)-C(40) ) 1.508(3), S-O(3) ) 1.423(2), S-O(4) )
1.428(2), S-O(2) ) 1.4559(17); C(50)-Pd-C(40) ) 92.71-
(8), C(40)-Pd-N(2) ) 81.56(7), C(50)-Pd-O(2) ) 94.25-
(8), N(2)-Pd-O(2) ) 91.16(6), C(10)-N(2)-C(21) ) 123.98-
(17), C(10)-N(2)-Pd ) 113.92(13), C(21)-N(2)-Pd )
121.87(13), C(30)-N(3)-C(31) ) 121.28(18), C(40)-N(4)-
C(41) ) 123.52(18), C(50)-N(5)-C(51) ) 178.1(2), N(2)-
C(10)-C(11) ) 128.62(18), N(2)-C(10)-C(30) ) 111.89(17),
C(11)-C(10)-C(30) ) 118.81(17), N(3)-C(30)-C(10) )
117.93(17), N(3)-C(30)-C(40) ) 128.39(17), C(10)-C(30)-
C(40) ) 112.49(16), N(4)-C(40)-C(30) ) 120.86(18), N(4)-
C(40)-Pd ) 136.12(16), C(30)-C(40)-Pd ) 102.93(12),
O(3)-S-O(4) ) 117.51(15), O(3)-S-O(2) ) 113.61(14),
O(4)-S-O(2) ) 113.67(13).
2.5469(4)-2.5451(4) (13b; aryl) > 2.5333(5)-2.5282(3)
(6b, 8a ,b, 10; L ) C(dNAr)Xy) > 2.5204(4)-2.4963(4)
(13b; PPh3) > 2.4259(3) (5b; L ) bpy). Similarly, the
Pd-N bond distances in 5b (Pd-N(4), 2.0655(18) Å;
Pd-N(3), 2.1441(17) Å) show the greater trans influence
of the C-donor iminoacyl ligand with respect to the
bromo ligand. Looking at these scales, our proposal that
the transphobia could be directly related to the trans
influence is reinforced.50 Under this assumption, two
ligands with great trans influence will suffer a great
transphobia.
The structure of the Pd(I) dimer 9 (Figure 6) is similar
to that of the few crystal structures reported of related
complexes [Pd2(CNR)4L2]n+: R ) Me, L ) MeNC, n )
2,59 L ) I, n ) 0;60 R ) tBu, L ) PPh3, n ) 2,21 L ) Cl,
n ) 0.61,62 9 contains two directly bonded Pd atoms, each
having two coordinated isocyanides in trans positions
Pd(I) complex [Pd2(PPh3)2(CNXy)4](TfO)2 as a conse-
quence of the high T[Ph3P/C(dNtBu)C6H4NH2-2-X-5] )
T1. The stability of 7d could mean that T1 > T[Ph3P/
C(dNXy)C6H4CHdCH2-2]. The cis disposition of both
C-donor ligands in 8a ,b and 11a ,b or of PPh3 and the
aryl ligand in 12a is consistent with the large T[C-
donor/C-donor] or T[C-donor/P-donor], respectively.
X-r a y Cr ysta l Str u ctu r es. The molecular structures
of 5b (Figure 1), 6b (Figure 2), 7d (Figure 3), 8a ‚1/2-
CH2Cl2 (Figure 4), 8b‚1/2CH2Cl2 (Figure 5), 9 (Figure
6), 10‚CH2Cl2 (Figure 7), 11a ‚1/2CHCl3 (Figure 8), 11b
(Figure 9), 12a (Figure 10), and 13b (Figure 11) have
been determined by X-ray diffraction studies. The Pd-C
bond distances of the iminoacyl ligands decrease, in
agreement with the decreasing trans influence of the
ligand L located in the trans position. Thus, these values
are as follows (in Å): 2.0726(18) (7d ; L ) PPh3) > 2.035-
(3)-1.983(3) (6b, 8a ,b, 10, 13b; L ) Br) ≈ 1.992(3) (13b;
L ) ArCN) J 1.988(2) (5b; L ) bpy) ) 1.9772(19)-
1.9681(18) (11a , 11b; L ) OTf). The Pd-Br distances
also allow us to correlate longer distances with greater
trans influence. Thus, the order is as follows (in Å):
(59) Goldberg, S. Z.; Eisenberg, R. Inorg. Chem. 1976, 15, 535.
(60) Rutherford, N. M.; Olmstead, M. M.; Balch, A. L. Inorg. Chem.
1984, 23, 2833.
(61) Marsh, R. E. Acta Crystallogr., Sect. B 1997, 53, 317.
(62) Yamamoto, Y.; Yamazaki, H. Bull. Chem. Soc. J pn. 1985, 58,
1843.

4466 Organometallics, Vol. 21, No. 21, 2002
Vicente et al.
F igu r e 10. Thermal ellipsoid plot (50% probability level)
of 12a . Selected bond lengths (Å) and angles (deg): Pd-
C(11) ) 1.9838(13), Pd-O(1) ) 2.1045(10), Pd-O(2) )
2.1373(10), Pd-P ) 2.2268(4), O(1)-C(17) ) 1.2521(17),
S-O(3) ) 1.4375(12), S-O(4) ) 1.4410(12), S-O(5) )
1.4442(12); C(11)-Pd-O(1) ) 81.91(5), O(1)-Pd-O(2) )
88.79(4), C(11)-Pd-P ) 95.32(4), O(2)-Pd-P ) 93.98(3),
O(3)-S-O(4) ) 114.95(8), O(3)-S-O(5) ) 114.27(8), O(4)-
S-O(5) ) 115.86(8).
F igu r e 11. Thermal ellipsoid plot (30% probability level)
of 13b. Hydrogen atoms, the anion, and the minor disorder
component of the C31-N3 ring are omitted. Selected bond
lengths (Å) and angles (deg): Pd(1)-C(11) ) 1.993(3), Pd-
(2)-C(21) ) 1.983(3), Pd(3)-C(31) ) 1.992(3), Pd(1)-P(1)
) 2.2609(8), Pd(2)-P(2) ) 2.2516(8), Pd(3)-P(3) ) 2.2522-
(8), Pd(1)-Br(2) ) 2.5204(4), Pd(1)-Br(1) ) 2.5469(4), Pd-
(2)-Br(1) ) 2.4963(4), Pd(2)-Br(2) ) 2.5451(4), Pd(3)-N(1)
) 2.088(2), Pd(3)-N(2) ) 2.102(3), N(1)-C(17) ) 1.144-
(3), N(2)-C(27) ) 1.141(4), S-O(1) ) 1.424(4), S-O(3) )
1.427(3), S-O(2) ) 1.439(3); C(11)-Pd(1)-P(1) ) 87.96-
(8), C(11)-Pd(1)-Br(2) ) 91.61(8), P(1)-Pd(1)-Br(1) )
93.39(2), Br(2)-Pd(1)-Br(1) ) 87.022(12), C(21)-Pd(2)-
P(2) ) 89.87(8), C(21)-Pd(2)-Br(1) ) 88.83(8), P(2)-Pd-
(2)-Br(2) ) 94.84(2), Br(1)-Pd(2)-Br(2) ) 87.578(12),
C(31)-Pd(3)-N(1) ) 88.30(11), N(1)-Pd(3)-N(2) ) 91.39-
(9), C(31)-Pd(3)-P(3) ) 88.36(9), N(2)-Pd(3)-P(3) )
92.12(7), Pd(2)-Br(1)-Pd(1) ) 83.789(12), Pd(1)-Br(2)-
Pd(2) ) 83.341(11), C(27)-N(2)-Pd(3) ) 176.9(3), N(2)-
C(27)-C(22) ) 177.4(3), C(17)-N(1)-Pd(3) ) 174.7(2),
N(1)-C(17)-C(12) ) 178.7(3), O(1)-S-O(3) ) 115.7(3),
O(1)-S-O(2) ) 114.2(3), O(3)-S-O(2) ) 114.9(2).
and a bromo ligand in the axial position. The angle
between the two coordination planes is 84°. The distance
between both palladium atoms (2.5269(3) Å) is the
shortest reported (published range 2.5310(9)-2.5596-
(7) Å). The Pd-C bond distances in 9 (1.966(2)-1.956-
(2) Å) are shorter than those in the Pd(II) complexes
6b, 7d , and 10, also containing mutually trans XyNC
ligands (range 1.999(3)-1.984(3) Å), although the Pd-
C(1) distance in 6b (1.969(3) Å) is significantly below
this range. However, the CtN bond distances are
similar for the above four complexes (range 1.161(2)-
1.146(4) Å), suggesting that the differences in Pd-C
bond distances are due to the different Pd-C σ bond
strengths and that the Pd-C π bond is probably
negligible in both groups of complexes. The C-N-C
angle of the isocyanides deviate slightly from linearity
(range 178.8(2)-171.89(18)°), supporting the proposal
of slight, if any, π-character of the Pd-C bond.
Ta ble 4. Hyd r ogen Bon d s for Com p lex 12a a
D-H‚‚‚A
D-H
H‚‚‚A
D‚‚‚A
The [Pd]CdNXy bond distances of the iminoacyl
ligands in complexes 5b, 6b, 7d , 8a ,b, 10, and 11a ,b
are in the range 1.267(3)-1.252(2) Å. In the triinserted
complexes 8 and 11, the CdN distances corresponding
to the second inserted molecule of XyNC are in the
upper limit of the above range (N(3)-C(30) ) 1.2704-
(19)-1.265(2) Å). All these lengths are as expected for
a CdN bond (the mean value for C(aryl)-CdNR dis-
tances is 1.279 Å).63 The (aryl)CdN(Xy)[Pd] distances
corresponding to the third inserted molecule of XyNC
in 8 and 11 are significantly longer than the other two
(N(2)-C(10) ) 1.291(2)-1.283(3) Å) as a result of the
coordination of the nitrogen atom to Pd. In the triin-
serted complex 10, the HN(2)-C(20) bond length (1.378-
(3) Å), corresponding to the second inserted isocyanide,
is intermediate between the above CdN distances and
that of the C(21)-N(2) bond (1.426(3) Å). This fact, the
wide C(21)-N(2)-C(20) angle (125.8(2)°), and the short
C(20)-C(40) bond (1.368(4) Å), compared with C(31)-
C(40) (1.476(4) Å), suggest a delocalization of π electron
O(2)-H(01)‚‚‚O(5)#1
O(2)-H(02)‚‚‚O(4)#2
O(2)-H(02)‚‚‚O(1)#3
C(13)-H(13)‚‚‚O(3)#4
0.785(16) 1.897(17) 2.6643(16) 165(2)
0.781(16) 2.110(17) 2.7521(16) 139.7(19)
0.781(16) 2.394(18) 2.9674(14) 131.2(18)
0.95
2.36
2.51
2.57
2.62
3.3097(19) 173.3
3.4874(19) 172.3
C(18)-H(18B)‚‚‚O(3)#4 0.98
C(23)-H(23)‚‚‚O(3)
C(26)-H(26)‚‚‚O(4)#2
0.95
0.95
3.305(2)
3.4712(19) 148.7
134.5
a
Distances are given in Å and angles in deg. Symmetry
transformations used to generate equivalent atoms: (#1) -x + 1,
-y + 1, -z + 1; (#2) x, y + 1, z; (#3) -x + 1, -y + 2, -z + 1; (#4)
x + 1, y + 1, z.
density around the N(2)-C(20)-C(40) group. Similarly,
the angles around N(4) (112.3(2), 119.7(2), and 127.9-
(2)°) and the short N(4)-C(37) bond distance (1.384(4)
Å) compared with those of N(4)-C(40) (1.439(3) Å) and
N(4)-C(41) (1.440(3) Å) also point to a delocalization
of π electron density along the N(4)-C(37)-O moiety.
The atoms C(31-36)-C40-C(20)-C(10)-N(2)-C(21)-
N(4)-C(41)-C37-O are almost coplanar. Some devia-
tions are as follows (in Å): C(20), 0.12; C(10), 0.22; N(2),
0.33; C(21), 0.04; C(41), 0.08.
Despite the structural similarity of the triflato com-
plexes 11a (Figure 8) and 11b (Figure 9), the Pd-O
(63) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. J . Chem. Soc., Perkin Trans. 2 1987, S1.

2-Substituted Phenyl Complexes of Palladium(II)
Organometallics, Vol. 21, No. 21, 2002 4467
bond distances are different (2.1678(15) and 2.1894(15)
Å, respectively). However, the triflate in 11b is disor-
dered over two positions with occupancies of ca. 2:1 and
the Pd-O(1) distance should not be regarded as very
reliable. The Pd-OTf distance seems to be very sensi-
tive to small changes in the nature of the trans ligand.
Thus, in the crystal structures of triflato complexes in
which this ligand is trans to a C-donor ligand, the values
of the Pd-O bond are in the wide range of 2.271(7)-
2.126(5) Å.17,50,64-66
Con clu sion s
2-R-arylpalladium(II) complexes containing the ligand
bpy react with XyNC to give monoinserted complexes
when the ortho substituent R is C(O)Me, CN (1:1 and
1:3 molar ratios), or CHdCH2 (1:3 molar ratio). When
the molar ratio was 1:1 and R ) C(O)Me, CN, the
corresponding monoinserted complex containing bpy
was isolated. When the molar ratio was 1:3 and R )
C(O)Me, CN, CHdCH2 monoinsertion and substitution
of bpy for two molecules of isocyanide took place. When
the (2-R-aryl)palladium(II) complex (R ) C(O)Me, CN,
CHdCH2) contained PPh3 as the only neutral ligand,
reactions with XyNC in a 1:3 molar ratio led to monoin-
serted products in which PPh3 had been substituted by
XyNC, but only when reactions were carried out in CH2-
Cl2 under nitrogen and were stopped almost immedi-
ately after mixing the reactants. When these reactions
were carried out with a long reaction time and in a 1:4
molar ratio, triinserted complexes were isolated. The
reaction of (2-R-aryl)palladium(II) complexes when R )
CHO with XyNC usually led to complex mixtures. Only
in one case (reaction of 1c with XyNC in a 1:5 molar
ratio) were we able to isolate a complex resulting from
the triinsertion of XyNC followed by a nucleophilic
attack at the formyl carbon of the nitrogen of the
primarily inserted isocyanide. Metathesis reactions of
some bromo complexes with Tl(TfO) gave triflato com-
plexes, a cyclopalladated aquo complex, or an unusual
trinuclear complex in which a dimeric (2-cyanoaryl)-
palladium complex acts as a chelating ligand of the Pd-
(C6H4CN-2)PPh3 moiety. The structure and stability of
some complexes provide new data on the concept of
transphobia. The extensive structural data allow the
proposal of various scales of trans influence and a
connection of these with the scale of transphobia.
In complex 12a , the phosphine and aryl ligands are
mutually cis, in agreement with the strong transphobia
of these ligands. The coordination of the oxygen of the
carbonyl group is responsible for the lengthening of the
C-O bond (1.2521(17) Å) with respect to that in 8a
(1.217(2) Å) or 11a (1.221(3) Å) and a shifting to lower
frequencies of the ν(CdO) band in its IR spectrum (see
above) with respect to those in the other complexes
containing the uncoordinated 2-acetylphenyl group (5a ,
6a , 8a , and 11a ). The packing of compound 12a involves
several hydrogen bonds of the types O-H‚‚‚O and C-
H‚‚‚O (see Table 4). Two formula units form a cen-
trosymmetric dimer through hydrogen bonds O(2)-
H(01)‚‚‚O(5) and the three-center O(2)-H(02)‚‚‚O(4)/
O(1). This dimeric structure is supported by the “weak”
hydrogen bond C(26)H(26)‚‚‚O(4) (H‚‚‚O ) 2.62 Å). The
dimers link to give a unidimensional polymer parallel
to the x axis via the bifurcate system C(13)-H(13)‚‚‚
O(3)‚‚‚H(18)-C(18) hydrogen bonds (H‚‚‚O ) 2.36, 2.51
Å). Finally, these polymeric units link to give a layer
parallel to the xz plane through O(3)‚‚‚H(23)-C(23)
hydrogen bonds (H‚‚‚O ) 2.57 Å).
The structure of the cation of 13b consists of a trans-
4b molecule coordinated through the nitrogen atoms of
both nitrile substituents to a cis-Pd(C6H4CN-2)(PPh3)
fragment (Figure 11). The molecular planes of Pd(1) and
Pd(2) (the dimeric unit) are folded, forming an angle of
40° associated with the coordination to Pd(3); note,
however, that the coordination at Pd(2) is far from
planar, with Br(2) lying 0.60 Å out of the plane of the
other four atoms. The coordination of the two nitrile
groups does not affect their CtN distances, since they
are very similar to that shown by the uncoordinated
nitrile (C(27)-N(2), 1.141(4) Å; C(17)-N(1), 1.144(3) Å;
C(37)-N(3), 1.139(5) Å).
Ack n ow led gm en t. We thank the Ministerio de
Ciencia y Tecnolog´ıa, the FEDER (Grant No. BQU2001-
0133), and the Fonds der Chemischen Industrie for
financial support. E.M.-V. thanks the Fundacio´n Se´neca
(Comunidad Auto´noma de la Regio´n de Murcia, Murcia,
Spain) for a Grant.
Su p p or tin g In for m a tion Ava ila ble: Listings of all re-
fined and calculated atomic coordinates, all anisotropic ther-
mal parameters, and all bond lengths and angles for the
complexes 5b, 6b, 7d , 8a ‚1/2CH2Cl2, 8b‚1/2CH2Cl2, 9, 10‚CH2-
Cl2, 11a ‚1/2CHCl3, 11b, 12a , and 13b. This material is avail-
able free of charge via the Internet at http://pubs.acs.org.
(64) Anderson, O. P.; Packard, A. B. Inorg. Chem. 1979, 18, 1129.
(65) Burger, P.; Baumeister, J . M. J . Organomet. Chem. 1999, 575,
214.
(66) Campora, J .; Lopez, J . A.; Palma, P.; Valerga, P.; Spillner, E.;
Carmona, E. Angew. Chem., Int. Ed. 1999, 38, 147.
OM020380S