Coordination modes of 3-aminosalicylic and 3-hydroxyanthranilic acids in palladium(II), platinum(II) and rhenium(V) complexes. The crystal structure of cis-[Pt(HsalNH)(PPh3)2] ? 0.25C2H 5OH

Article abstract of DOI:10.1016/j.poly.2005.07.034

New Pd(II), Pt(II) and Re(V) complexes of 3-aminosalicylic acid (H ₂salNH₂) and 3-hydroxyantranilic acid (HantOH) have been prepared, cis-[Pt (HsalNH)(PPh₃)₂] ? 0.25C ₂H₅OH (1), trans-[PdCl

Full text of DOI:10.1016/j.poly.2005.07.034

Polyhedron 25 (2006) 753–758
www.elsevier.com/locate/poly
Coordination modes of 3-aminosalicylic and 3-hydroxyanthranilic
acids in palladium(II), platinum(II) and rhenium(V) complexes.
The crystal structure of cis-[Pt(HsalNH)(PPh3)2] Æ 0.25C2H5OH
a
a
b
a,
*
´
Susana M.O. Quintal , Vitor Felix , Michael G.B. Drew , Helena I.S. Nogueira
a
Department of Chemistry, CICECO, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
b
School of Chemistry, University of Whiteknights, Reading RG6 6AD, UK
Received 19 April 2005; accepted 25 July 2005
Available online 5 October 2005
Abstract
New Pd(II), Pt(II) and Re(V) complexes of 3-aminosalicylic acid (H2salNH2) and 3-hydroxyantranilic acid (HantOH) have been
prepared, cis-[Pt (HsalNH)(PPh3)2] Æ 0.25C2H5OH (1), trans-[PdCl(salNH2)(PPh3)2] (2), trans-[ReOI2(HsalNH2)(PPh3)] Æ (CH3)2CO
(3), cis-[Pt(HantO)(PPh3)2] (4), trans-[PdCl(antOH)(PPh3)2] Æ 4H2O (5), [PdCl(antOH)(bipy)] Æ C2H5OH (6), [PdCl2(HantOH)2] (7)
and trans-[ReOI(HantO)(PPh3)2] Æ (CH3)2CO (8). The crystal structure of complex 1 was determined showing chelation of
1
HsalNH2ꢀ through the adjacent nitrogen and oxygen atoms of the amino and phenolate groups. Infrared and H NMR spectro-
scopic data for the complexes are presented.
Ó 2005 Elsevier Ltd. All rights reserved.
Keywords: 3-Aminosalicylic acid; 3-Hydroxyanthranilic acid; Crystal structure; Palladium; Platinum; Rhenium
1. Introduction
ing, or by two different chelates either the O,O-chelate,
involving the carboxylate group and the oxygen in posi-
tion-2, resulting in a six-membered chelate-ring, or the
N,O-chelate, involving the amino group nitrogen and
the oxygen in position-2, with the formation of a five-
membered chelate-ring. A similar O,O-chelate is found
in complexes of salicylic acid and derivatives, such as
[MoO2L2]2ꢀ (H2L = salicylic acid, 4- or 5-methyl-
salicylic acids), [PdL2] (H2L = salicylic acid) [7],
[MoO2L2]2ꢀ, [OsO2(py)2L], [ReOIL(PPh3)] (H2L = 2,6-
dihydroxybenzoic acid; py = pyridine) [8].
When deprotonated, 3-hydroxyanthranilic acid can
also bind to metals by several coordination modes:
monodentate O or N donor, bridging, or by two possi-
ble N,O-chelating modes, involving the nitrogen atom
and the oxygen atom of either the hydroxyl group
(forming a five-membered chelate-ring) or the carboxyl
group (forming a six-membered chelate-ring). The for-
mer is found in complexes with 2-aminophenolate and
We have been studying the coordination modes of
aromatic ambidentade ligands, such as 3-hydroxypicoli-
nic acid [1,2], 2-hydroxynicotinic acid [3] and 2,3-, 3,4-
and 2,6-dihydroxybenzoic acids, with 2nd and 3rd row
transition metals and the lanthanides [4–6]. In the pres-
ent work a comparative study was done on Pd(II), Pt(II)
and Re(V) complexes with 3-aminosalicylic (H2salNH2)
and 3-hydroxyantranilic acids (HantOH), respectively.
The two ligands are constitutional isomers: 3-aminosal-
icylic acid is 3-amino-2-hydroxybenzoic acid (Fig. 1(a)),
and 3-hydroxyanthranilic acid is 2-amino-3-hydroxy-
benzoic acid (Fig. 1(b)).
3-Aminosalicylic acid can bind to metals by several
coordination modes: monodentate O or N donor, bridg-
*
Corresponding author. Tel.: +351234370727; fax: +351234370084.
E-mail address: helena@dq.ua.pt (H.I.S. Nogueira).
0277-5387/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2005.07.034

754
S.M.O. Quintal et al. / Polyhedron 25 (2006) 753–758
H6
C6
(PPh3)2] Æ (CH3)2CO (8) were synthesised by refluxing
trans-[ReOI2(OEt) (PPh3)2] with H2salNH2 or HantOH
in acetone.
H6
C6
H5
H5
C (7)OOH
OH
C (7)OOH
NH2
C5
C4
C1
C2
C5
C4
C 1
C2
2.2. Crystal structure of 1
C3
H4
C3
H4
The X-ray diffraction study of 1 shows that its crystal
structure is built up from an asymmetric unit composed
of one molecule of cis-[Pt(HsalNH)(PPh3)2] and several
solvent molecules of ethanol all with reduced occu-
pancy. An ORTEP view showing the overall geometry
of the complex and the atomic notation scheme is pre-
sented in Fig. 2. Bond lengths and angles are listed in
Table 1 for complex 1. The platinum(II) centre is sur-
rounded by the nitrogen and oxygen atoms from the
amino and phenol groups of the HsalNH2ꢀ ligand and
the phosphorus atoms of the two PPh3 ligands in a dis-
torted square planar coordination environment. The an-
gle N–Pt–O of 79.32(3)° is dictated by the O–N bite
angle of the HsalNH2ꢀ ligand while the remaining an-
gles in the metal coordination sphere are the result of
NH2
OH
a
b
Fig. 1. 3-Aminosalicylic (a) and 3-hydroxyanthranilic (b) acids and
numbering scheme adopted.
derivatives such as [MoO2(HL)2] (H2L = 2-amino-4-
clorophenol, 2-amino-4-methylphenol) and [OsL3]
(H2L = 2-amino-4-methylphenol, 2-amino-4-tbutylphe-
nol), [MoO2(HL)2] [9] and [PtL(PPh3)2] [10] (H2L =
2-aminophenol), [V(@NPh)(OC6H2(CH2NMe2)-2-Me2-
4,6)2] [11], [V(OC6H2(CH2NMe2)-2,6-Me-4)3] and
[VCl(OC6H2(CH2NMe2)-2-Me-4)2] [12]. The latter che-
lating mode is found in complexes of anthranilic acid
like [MoCl3{2-(HN)C6H4CO2}{2-Me3SiO2CC6H4N}]ꢀ,
[MoCl3{2-(HN)C6H4CO2}(NC6H3Pri2-2,6)]ꢀ [13] and
[Ba(2-NH2C6H4CO2)2(OH2)]n [14].
The N,O-chelating mode in H2salNH2 is similar
to the N,O-chelating mode with HantOH, forming
five-membered chelate-rings. The formation of six-
membered chelate-rings is in the case of H2salNH2
achieved through bonding to a carboxylate O atom and
a hydroxyl O atom, and in the case of HantOH to a car-
boxylate O atom and an amino N atom. The coordina-
tion modes described were investigated in Pd(II), Pt(II)
and Re(V) complexes using spectroscopic data and in
one case X-ray diffraction data. The crystal structure of
the Pt(II) compound 1 was determined and in this com-
plex the 3-aminosalicylato ligand shows coordination
through the nitrogen and oxygen atoms of the amino
and phenolate groups (N,O-chelating mode). Spectro-
scopic characterisation of the remaining compounds sug-
gests that other coordination modes may occur.
2. Results and discussion
Fig. 2. An ORTEP view of cis-[Pt(HsalNH)(PPh3)2] (1) showing the
overall molecular geometry. Ellipsoids are drawn at 30% probability
level.
2.1. Preparations
Suspensions of cis-[PtCl2(PPh3)2] or trans-[PdCl2-
(PPh3)2] and H2salNH2 or HantOH in an ethanol/
methanol mixture in the presence of triethylamine gave
complexes cis-[Pt(HsalNH)(PPh3)2] Æ 0.25C2H5OH (1),
trans-[PdCl(HsalNH2)(PPh3)2] (2), cis-[Pt(HantO)-
(PPh3)2] (4) and trans-[PdCl(antOH)(PPh3)2] Æ 4H2O
(5). When K2[PdCl4] was used as starting material,
the compound obtained was [PdCl2(HantOH)2] (7).
Reaction of the 2,20-bipyridine (bipy) complex [PdCl2
(bipy)] with HantOH gave compound 6, [PdCl(antOH)
(bipy)] Æ C2H5OH. The complexes trans-[ReOI2(Hsal-
NH2)(PPh3)] Æ (CH3)2CO (3) and trans-[ReOI(HantO)
Table 1
˚
Selected distances (A) and angles (°) for complex 1
Pt–N(22)
Pt–P(1)
Pt–O(21)
Pt–P(2)
2.014(6)
2.289(2)
2.069(5)
2.226(2)
N(22)–Pt–P(1)
P(2)–Pt–O(21)
N(22)–Pt–P(2)
P(1)–Pt–P(2)
N(22)–Pt–O(21)
P(1)–Pt–O(21)
166.5(2)
174.2(2)
95.0(2)
99.4(1)
80.4(2)
86.1(2)

S.M.O. Quintal et al. / Polyhedron 25 (2006) 753–758
755
the minimisation of the steric interactions between the
HsalNH2ꢀ ligand and the two bulky PPh3 ligands. The
bond lengths to the metal centre are within the values
found for related complexes such as cis-[PtCl(picOH)
(PPh3)2] [1] and cis-[PtCl(HnicO)(PPh3)2] [3].
COOꢀ coordination fashion, possibly unidentate [18,19].
In 1–4, 7 and 8, the carboxyl group is possibly not
involved in the coordination because of the increase of
the m(C@O) frequency. In complex 1, the charge
balance constrains a 2ꢀ charge in the deprotonated
form of the 3-aminosalicylic acid. Assuming the
1721 cmꢀ1 frequency as the C@O stretch, characteristic
of the carboxyl group, the deprotonation possibly
occurs in the phenolic and amino groups (according to
crystal structure data). Similar deprotonation was des-
cribed for [MoCl3{2-(HN)C6H4CO2}{2-Me3SiO2CC6-
H4N}]ꢀ, [MoCl3{2-(HN)C6H4CO2}(NC6H3Pri2-2,6)]ꢀ
[13] and [Pt{2-(HN)C6H4O}(PPh3)2] [10]. The stretching
2.3. Infrared spectra
Infrared data for H2salNH2, HantOH and complexes
1–8 are given in Table 2. Tentative assignments are
based on those found in the literature for 3-aminosali-
cylic acid [15], salicylic acid [7], anthranilic acid and
derivatives [16,17], 2-aminophenol [9], 3-hydroxypicoli-
nic acid [1,2], and respective complexes. The most sensi-
tive bands to metal coordination were selected, namely
the C@O and C–O stretches of the carboxyl group,
m(C@O) and m(C–O)c, the bending mode of the amino
group, d(NH2), the C–O stretch of the phenolic group,
m(C–O)OH, and the C–NH2 stretch, m(C–NH2).
The bending frequency of the NH2 group, d(NH2), of
3-aminosalicylic acid is assigned at 1537 cmꢀ1 and of 3-
hydroxyanthranilic acid at 1548 cmꢀ1. In all complexes,
this frequency shifts to higher wavenumbers. For com-
plexes 5 and 6 it shifts only 3 cmꢀ1. For complexes 1,
3, 4, 7 and 8 this shift is higher than 42 cmꢀ1 showing
that the amino group may be involved in the coordina-
tion to metals. It suggests that in complexes 5 and 6 the
coordination may involve only the carboxylate or phe-
nolate groups.
C–O frequency of the phenolic group, m(C–O)OH
,
(1319 cmꢀ1 in H2salNH2 spectra and 1299 cmꢀ1 in
HantOH) shifts to lower wavenumbers in the spectra
of all complexes. It is particularly significant for com-
plexes 1–4 and 8, suggesting that in these complexes
the oxygen atom of the phenolic group may be involved
in coordination to the metals. The decrease in the
C–NH2 stretch frequency, m(C–NH2), in the spectra of
the complexes 1, 3, 4, 7 and 8 indicates that the amino
group may be coordinated to the metals.
The results described suggest the following coordina-
tion modes of 3-aminosalicylic or 3-hydroxyanthranilic
acids: in complexes 1, 3, 4 and 8 via chelation-NO
through the nitrogen atom of the amino group and
the oxygen atom of the phenolate group; in complexes
5 and 6 through one of the oxygen atoms of the car-
boxylate group; in complex 2 via monodentate-O of
the phenolate group; and in complex 7 via monoden-
tate-N.
The spectra of compounds 1–5 and 8 show three
characteristic bands of the PPh3 ligands, around 1480,
1435 and 1095 cmꢀ1, assigned to the symmetric and
asymmetric stretching and bending of P–Ph bonds,
respectively [17,19]. The strong bands at 974 and
979 cmꢀ1 in the spectra of the rhenium complexes 3
and 8, respectively, are assigned to Re@O stretch [1].
Two strong bands at 1651 and 1394 cmꢀ1 in the spec-
trum of 3-aminosalicylic acid are assigned to the C@O
and C–O stretches, m(C@O) and m(C–O)c, of the carboxyl
group, respectively. In the spectrum of 3-hydroxyanthra-
nilic acid these bands are seen at 1651 cmꢀ1 and
1344 cmꢀ1, respectively. The m(C@O) frequency decreases
in complexes 5 and 6, and the m(C–O)c frequency in-
creases. The calculated Dm(CO2) values, defined by Dea-
con and Phillips as mas(CO2) ꢀ ms(CO2), of 267 and
233 cmꢀ1 for 5 and 6, respectively, indicate a typical
Table 2
Infrared data (cmꢀ1) for 3-aminosalicylic and 3-hydroxyanthranilic acids and complexes 1–8
Compound
m(C@O)
d(NH2)a
m(C–O)c
m(C–O)OH
m(C–NH2)b
m(M–N)
m(M–Cl)
3-Aminosalicylic acid
1651 vs
1721 vs
1700 m
1671 m
1537 vs
1587 m
1571 m
1581 s
1394 vs
1373 m
1390 m
1370 s
1319 vs
1302 vs
1308 m
1303 m
1262 vs
1227 s
1283 m
1240 m
cis-[Pt(HsalNH)(PPh3)2] Æ 0.25C2H5OH (1)
trans-[PdCl(HsalNH2)(PPh3)2] (2)
trans-[ReOI2(HsalNH2)(PPh3)] Æ (CH3)2CO (3)
399 w
457 m
389 m
3-Hydroxyanthranilic acid
cis-[Pt(HantO)(PPh3)2] (4)
trans-[PdCl(antOH)(PPh3)2] Æ 4H2O (5)
[PdCl(antOH)(bipy)] Æ C2H5OH (6)
[PdCl2(HantOH)2] (7)
1651 vs
1679 sh
1635 m
1603 vs
1666 vs
1680 m
1548 vs
1615 s
1551 m
1551 s
1590 s
1602 m
1344 s
1323 s
1368 s
1370 vs
1337 s
1296 s
1299 vs
1251 vs
1275 vs
1276 vs
1293 vs
1242 vs
1221 vs
1213 vs
1249 m
1250 sh
1215 vs
1215 s
350 w
458 m
350 w
336 m
328 s, 307 s
trans-[ReOI(HantO)(PPh3)2] Æ (CH3)2CO (8)
vs, very strong; s, strong; m, medium; w, weak; sh, shoulder.
a
d(NH) in complexes 1, 4 and 8.
m(C–NH) in complexes 1, 4 and 8.
b

756
S.M.O. Quintal et al. / Polyhedron 25 (2006) 753–758
Table 3
1H NMR data for for 3-aminosalicylic and 3-hydroxyanthranilic acids and its complexes
Compound
Chemical shift (ppm)A
H4
H5
H6
3-Aminosalicylic acida
cis-[Pt(HsalNH)(PPh3)2] Æ 0.25C2H5OH (1)b
trans-[ReOI2(HsalNH2)(PPh3)] ꢁ (CH3)2CO (3)c
7.02 dd (5, 26)
6.31 d (25)
7.49 dd (5, 26)
6.72 t (26)
6.44 t (26)
6.99 t (26)
7.37 dd (5, 26)
6.96 d (25)
7.73 dd (5, 26)
3-Hydroxyanthranilic acida
cis-[Pt(HantO)(PPh3)2] (4)b
[PdCl(antOH)(bipy)] (6)d
[PdCl2(HantOH)2] (7)c
trans-[ReOI(HantO)(PPh3)2] Æ (CH3)2CO (8)c
A
6.80 dd (5, 26)
6.47 d (25)
7.21 d (26)
6.79 d (25)
6.98 dd (5, 26)
6.45 t (26)
6.25 t (25)
6.74 t (26)
6.36 t (26)
6.74 t (26)
7.35 dd (5, 27)
7.05 d (27)
8.02 d (25)
7.20 d (27)
7.33 dd (5, 27)
J values in parentheses (Hz); dd, doublet-doublet; t, triplet; d, doublet.
a
b
c
In CD3OD.
In CDCl3.
In dmso-d6.
D2O.
d
1
2.4. H NMR spectra
[24] and trans-[ReOI2(OEt)(PPh3)2] [25] were prepared
by the respective literature procedures.
1H NMR data and tentative assignments for 3-
aminosalicylic and 3-hydroxyanthranilic acids and its
complexes are shown in Table 3. Assignments are based
on those find in the literature for salicylic acid [20] and
derivates [16] and 2-aminophenol [9,21], anthranilic acid
[13,18] and derivates [17] and salicylic acid complexes
[7].
3.1.1. cis-[Pt(HsalNH)(PPh3)2] Æ 0.25C2H5OH (1)
To a stirred suspension of cis-[PtCl2(PPh3)2] (0.12 g,
0.15 mmol) in ethanol (5 cm3) was added a methanolic
suspension (5 cm3) of 3-aminosalicylic acid (0.05 g,
0.3 mmol) and triethylamine (0.08 cm3, 0.6 mmol). The
resulting yellow suspension was stirred for one day. It
was centrifuged and a yellow solid isolated. Orange crys-
tals were formed by recrystallisation in ethanol, washed
whith water and dried over silica gel. Yield: 0.05 g,
0.06 mmol, 40%.
1
The H NMR spectrum of 3-aminosalicylic acid in
CD3OD shows a triplet at 6.72 ppm assigned to the
H5 proton and two doublet-doublets at 7.02 and
7.37 ppm assigned to the H4 and H6 protons, respec-
1
tively. Similarly the H NMR spectrum of 3-hydroxy-
Elemental analysis. Calc.: C, 58.3; H, 4.3; N, 1.6.
Exp.: C, 59.9; H, 4.1; N, 1.6%. MS = 871; MW =
870.768 calculated for [Pt(HsalNH)(PPh3)2].
anthranilic acid in CD3OD shows a triplet at 6.45 ppm
assigned to the H5 proton, a doublet-doublet at
6.80 ppm assigned to the H4 proton and another
doublet-doublet at 7.35 ppm assigned to the H6 proton.
3.1.2. trans-[PdCl(HsalNH2)(PPh3)2] (2)
ꢀ
The proton signals of HsalNH2 in complex 2 and of
To a stirred suspension of trans-[PdCl2(PPh3)2]
(0.15 g, 0.15 mmol) in ethanol (5 cm3) was added a
methanolic suspension (5 cm3) of 3-aminosalicylic acid
(0.05 g, 0.3 mmol) and triethylamine (0.08 cm3,
0.6 mmol). The resulting suspension was refluxed for
1 h and filtered. To the orange filtrate was added
10 cm3 of water and a orange solid was formed. It was
centrifuged, washed with water and dried over silica
gel. Yield: 0.05 g, 0.06 mmol, 40%.
antOHꢀ in complex 5 are overlapped with the PPh3 sig-
nals. In the spectra of complex 6, the major shifts down-
field are observed for H4 and H6 protons. These are
higher than the shifts observed in complexes 4 and 8
with suggested NO-chelation. Relative to the free ligand,
the protons of HsalNH2ꢀ ligand in the Pt complex 1
shift upfield and in the Re complex 3 shift downfield;
the same trend is observed for the protons of HantOꢀ
ligand in complexes 4 (Pt) and 8 (Re), having all the sug-
gested NO-chelation .
Elemental analysis. Calc.: C, 63.1; H, 4.4; N, 1.7.
Exp.: C 61.4, H 4.6, N 1.7%.
3.1.3. trans-[ReOI2(HsalNH2)(PPh3)] Æ (CH3)2CO
(3)
3. Experimental
A suspension of trans-[ReOI(OEt)2(PPh3)2] (0.31 g,
0.3 mmol) and 3-aminosalicylic acid (0.05 g, 0.3 mmol)
in acetone (20 cm3) was refluxed for 1 h. It was centri-
fuged and a green solid obtained. It was washed with
acetone and dried over silica gel. Yield: 0.20 g,
0.21 mmol, 68%.
3.1. Preparation of complexes
All chemicals were of at least reagent grade and used
as supplied by Aldrich. The starting complexes, trans-
[PdCl2(PPh3)2] [22], cis-[PtCl2(PPh3)2] [23], [PdCl2(bipy)]

S.M.O. Quintal et al. / Polyhedron 25 (2006) 753–758
757
Elemental analysis. Calc.: C, 36.2; H, 2.9; N, 1.5.
3.1.8. trans-[ReOI(HantO)(PPh3)2] Æ (CH3)2CO (8)
Exp.: C, 36.3; H, 3.1; N, 1.6%.
A suspension of trans-[ReOI2(OEt)(PPh3)2] (0.31 g,
0.3 mmol) and 3-hydroxyantharanilic acid (0.05 g,
0.3 mmol) in acetone (10 cm3) was refluxed for 30 min.
After cooling to room temperature, 10 cm3 of water
were added and a brownish solid was formed, isolated,
washed with water and dried over silica gel. Yield:
0.20 g, 0.19 mmol, 63%.
3.1.4. cis-[Pt(HantO)(PPh3)2] (4)
To a stirred suspension of cis-[PtCl2(PPh3)2] (0.12 g,
0.15 mmol) in ethanol (5 cm3) was added a methanolic
suspension (5 cm3) of 3-hydroxyanthranilic acid
(0.05 g, 0.3 mmol) and triethylamine (0.08 cm3,
0.6 mmol). The resulting yellow suspension was stirred
for one day. It was centrifuged and a yellow solid iso-
lated, washed with ethanol and dried over silica gel.
Yield: 0.11 g, 0.13 mmol, 87%.
Elemental analysis. Calc.: C, 51.9; H, 4.0; N, 1.3.
Exp.: C, 54.9; H, 4.1; N, 1.5%.
3.2. X-ray diffraction
Elemental analysis. Calc.: C, 59.3; H, 4.1; N, 1.6.
Exp.: C, 59.9; H, 4.1; N, 1.6%. MS = 871; MW =
870.768 calculated for [Pt(HantO)(PPh3)2].
C
44.50H40NO3.75P2Pt (1), Mr = 905.80, triclinic, space
˚
˚
ꢀ
group P1, a = 9.749(12) A; b = 13.954(15) A; c = 16.333
˚
(17) A; a = 74.23(1)°; b = 84.14(1)°, c = 74.15(1)°, U =
2056.0 A , Z = 2, qcalc = 1.463 Mg mꢀ3, l(Mo Ka) =
3
˚
3.1.5. trans-[PdCl(antOH)(PPh3)2] Æ 4H2O (5)
To a stirred suspension of trans-[PdCl2(PPh3)2]
(0.35 g, 0.5 mmol) in ethanol (5 cm3) was added a meth-
anolic suspension (4 cm3) of 3-hydroxyanthranilic acid
(0.15 g, 1 mmol) and triethylamine (0.28 cm3, 2 mmol).
The resulting suspension was stirred for 1 h. It was cen-
trifuged and a orange solution was obtained. Part of the
solvent was evaporated and a red solid was obtained by
addition of an equal amount of water. This solid was
washed with water and dried over silica gel. Yield:
0.13 g, 0.27 mmol, 54%.
3.531 mmꢀ1
.
X-ray data were collected at room temperature on a
MAR research plate system using graphite monochro-
matised Mo Ka radiation (k = 0.71073 A) at Reading
˚
University. The crystal was positioned at 70 mm from
the image plate. 95 frames were taken at 2° intervals
with an adequate counting time. Data analysis was per-
formed with the XDS program [26]. Intensities were
corrected empirically for absorption effects, using a
DIFABS version modified for image plate geometry
[27].
The structure was solved by a combination of direct
methods and difference Fourier syntheses. The hydro-
gen atoms on the parent carbon atoms and aliphatic
nitrogen atoms were included in calculated positions
and giving thermal parameters equivalent 1.2 times
those of the atom to which were attached. The non-
hydrogen atoms were refined with anisotropic thermal
parameters
Elemental analysis. Calc.: C, 58.0; H, 5.0; N, 1.6.
Exp.: C, 58.0; H, 5.3; N, 2.1%.
3.1.6. [PdCl(antOH)(bipy)] Æ C2H5OH (6)
To a stirred suspension of [PdCl2(bipy)] (0.05 g,
0.15 mmol) in ethanol (5 cm3) was added a methanolic
suspension (5 cm3) of 3-hydroxyanthanilic acid (0.05 g,
0.3 mmol) and triethylamine (0.08 cm3, 0.6 mmol). The
resulting yellow suspension was stirred for three days.
It was centrifuged and a brownish solid isolated, washed
with ethanol and dried over silica gel. Yield: 0.07 g,
0.14 mmol, 93%.
The final refinement of 464 parameters by full-matrix
least-squares method against F2 until convergence to be
achieved leading to final indices R1 = 0.0412 and
wR2 = 0.1126 for 5710 reflections with I > 2r(I) and
R1 = 0.0521 and wR2 = 0.1205, for all intensity data
comprising 6578 reflections. The residual electronic den-
Elemental analysis. Calc.: C, 46.0; H, 4.1; N, 8.5.
Exp.: C, 45.9; H, 4.1; N, 9.9%. MS = 413; MW =
414.731 calculated for [Pd(antOH)(bipy)]+.
sity was in the range ꢀ1.189 to 2.347 e Aꢀ3, with posi-
˚
˚
tive hole 0.96 A within platinum coordination sphere
˚
3.1.7. [PdCl2(HantOH)2] (7)
while the negative one is only 1.44 A way from the cal-
A methanolic suspension (4 cm3) of 3-hydroxyanth-
ranilic acid (0.15 g, 1 mmol) was added to an aqueous
solution (5 cm3) of K2[PdCl4] (0.16 g, 0.5 mmol). The
resulting orange suspension was stirred for one day. It
was centrifuged and a yellow solid isolated, washed with
ethanol and dried over silica gel. Yield: 0.22 g,
0.45 mmol, 90%.
culated position for an hydrogen atom. All calculations
required to solve and to refine the structure were carried
out using the SHELX-97 system programs [28]. Molecular
diagrams were drawn with PLATON [29].
3.3. Instrumentation
Elemental analysis. Calc.: C, 34.8; H, 2.9; N, 5.8.
Exp.: C, 34.6; H, 3.4; N, 6.2%. MS = 485; MW =
483.596 calculated for [PdCl2(antOH)2]. MS = 411;
Infrared spectra were measured as KBr pellets on a
Mattson 7000 FT instrument. 1H NMR spectra were re-
corded on a Bruker AMX300 spectrometer at 300 MHz
¨
MW = 412.690 calculated for [Pd(antOH)2]2+
.
and referenced to SiMe4 or the solvent. Microanalyses

758
S.M.O. Quintal et al. / Polyhedron 25 (2006) 753–758
´
[5] P.C.R. Soares-Santos, H.I.S. Nogueira, J. Rocha, V. Felix,
(C, H and N) were measured by the Department of
Chemistry, University of Aveiro.
´
M.G.B. Drew, R.A. Sa Ferreira, L.D. Carlos, T. Trindade,
Polyhedron 22 (2003) 3529.
[6] P.C.R. Soares-Santos, H.I.S. Nogueira, F.A. Almeida Paz, R.A.
´
Sa Ferreira, L.D. Carlos, J. Klinowski, T. Trindade, Eur. J.
Acknowledgements
Inorg. Chem. (2003) 3609.
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A.J.P. White, D.J. Williams, J. Chem. Soc., Dalton Trans. (1995)
1775.
The authors acknowledge Fundac¸ao para a Cieˆncia e
˜
a Tecnologia (FCT, Portugal) for financial support.
S.M.O. Quintal thanks FCT for a postgraduate grant.
We also thank EPSRC (UK) and the University of
Reading (UK) for funds for the Image Plate System.
[9] W.P. Griffith, T.Y. Hoh, D.J. Williams, J. Chem. Soc., Dalton
Trans. (1993) 3459.
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Spek, G. Koten, Inorg. Chem. 39 (2000) 3970.
Appendix A. Supplementary data
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J.F. Richardson, Polyhedron 18 (1999) 1189.
Crystallographic data for the structure reported in
this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publica-
tion no. CCDC 269712. Copies of the data can be ob-
tained free of charge on application to CCDC, 12
Union Road, Cambridge CB2 2EZ, UK (fax: (+44)
1223 336033; e-mail: deposit@ccdc.cam.ac.uk, and
http://www.ccdc.cam.ac.uk). Supplementary data asso-
ciated with this article can be found, in the online
version at doi:10.1016/j.poly.2005.07.034.
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