Palladium(II) and platinum(II) monoselenocarboxylates: Synthesis, spectroscopy, structure and their use as molecular precursors for metal selenides

Article abstract of DOI:10.1016/j.ica.2005.06.080

Treatment of MCl₂(P^∩P) or MCl₂(P ⁿPr₃)₂ with two equivalents of ArCOSeK readily yields cis-[M(SeCOAr)₂(P^∩P)] and trans-[M(SeCOAr) ₂(PⁿPr₃)₂], respectively (M = Pd or Pt; Ar = Ph or 4-MeC₆H₄; P^∩P = dppm, dppe, dppp). The reaction of Pd(SeCOAr)₂(dppe) with PdCl₂(dppe) in the presence of NaBPh₄ in methanol gave a tri-nuclear ionic complex, [Pd₃(μ₃-Se)₂(dppe) ₃][BPh₄]₂. These complexes were characterized by UV-Vis, IR and NMR spectroscopy. The complex [Pt(SeCOPh)₂(dppp)] has been structurally characterized by X-ray crystallography. The coordination environment around square planar platinum atom is defined by chelating dppp ligand and two unidentate selenocarboxylates bonded through selenium atoms. Pyrolysis of [Pd(SeCOAr)₂(PⁿPr₃)₂] either in tri-n-butylphosphate (TBP) (at 200°C) or in the solid state (furnace heating at 350°C) gave Pd₁₇Se₁₅.

Full text of DOI:10.1016/j.ica.2005.06.080

Inorganica Chimica Acta 359 (2006) 409–416
www.elsevier.com/locate/ica
Palladium(II) and platinum(II) monoselenocarboxylates:
Synthesis, spectroscopy, structure and their use as
molecular precursors for metal selenides
a
a,
b
Liladhar B. Kumbhare , Vimal K. Jain *, Babu Varghese
a
Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
b
Regional Sophisticated Instrumentation Center, Indian Institute of Technology, Chennai 600 036, India
Received 9 March 2005; accepted 17 June 2005
Available online 2 September 2005
Abstract
Treatment of MCl2(P\P) or MCl2(PnPr3)2 with two equivalents of ArCOSeK readily yields cis-[M(SeCOAr)2(P\P)] and trans-
[M(SeCOAr)2(PnPr3)2], respectively (M = Pd or Pt; Ar = Ph or 4-MeC6H4; P\P = dppm, dppe, dppp). The reaction of Pd(SeC-
OAr)2(dppe) with PdCl2(dppe) in the presence of NaBPh4 in methanol gave a tri-nuclear ionic complex, [Pd3(l3-Se)2(dppe)3][BPh4]2.
These complexes were characterized by UV–Vis, IR and NMR spectroscopy. The complex [Pt(SeCOPh)2(dppp)] has been structur-
ally characterized by X-ray crystallography. The coordination environment around square planar platinum atom is defined by che-
lating dppp ligand and two unidentate selenocarboxylates bonded through selenium atoms. Pyrolysis of [Pd(SeCOAr)2(PnPr3)2]
either in tri-n-butylphosphate (TBP) (at 200 ꢀC) or in the solid state (furnace heating at 350 ꢀC) gave Pd17Se15.
ꢁ 2005 Elsevier B.V. All rights reserved.
Keywords: Palladium; Platinum; Selenocarboxylate; Crystal structure; NMR
1. Introduction
chalcogenolate complexes [13–16]. In persuance of our
program on molecular design of platinum group chalco-
genolate precursors, facile decomposition of seleno- and
telluro-carboxylates has attracted our attention.
Although selenocarboxylates of alkali metals [17–19]
and some of the p-block elements [20–26] have been
investigated, there are only few reports dealing with
the complexes of transition metals [27]. Herein we report
the synthesis and chemistry of palladium(II) and plati-
num(II) monoselenocarboxylate complexes.
Platinum group metal chalcogenides find extensive
applications in catalysis and electronic industry [1]. Plat-
inum group metal chalcogenolates have attracted con-
siderable attention not only due to their rich structural
chemistry [2–5] and relevance in catalysis [6–9] but also
due to their potential as single source precursors for the
synthesis of metal chalcogenides [1]. Mononuclear chal-
cogenolate complexes with cis configuration have been
employed as molecular tactons for the synthesis of bi-
and high-nuclearity complexes [10–12].
In view to develop low decomposition temperature
precursors with cleaner depositions, we have recently ex-
plored the chemistry of several palladium and platinum
2. Results and discussion
2.1. Preparation and spectroscopic properties
*
Corresponding author. Tel.: +91 22 25595095; fax: +91 22
The reaction of cis-MCl2(P\P) or trans-MCl2(PnPr3)2
25505150.
with two equivalents of KSeCOAr in dichloromethane–
E-mail address: jainvk@apsara.barc.ernet.in (V.K. Jain).
0020-1693/$ - see front matter ꢁ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.06.080

410
L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
methanol mixture gave complexes of composition
[M(SeCOAr)2(P\P)] or [M(SeCOAr)2(PnPr3)2] (M = Pd
or Pt; Ar = Ph or 4-MeC6H4; P\P = dppm, dppe, dppp)
(Scheme 1) as yellow-orange crystalline solids. The com-
plexes [Pd(SeCOAr)2(PnPr3)2] when treated with
PdCl2(PnPr3)2 in dichloromethane gave a redistribution
product, [PdCl(SeCOAr)(PnPr3)2].
metal–selenium bond in metal complexes perturbs con-
jugation with carbonyl bond order approaching double
bond character. The electronic spectra of these com-
plexes showed a band in the region 310–360 nm, which
may be attributed to ligand-to-ligand charge transfer
transition [30].
1H NMR spectra of these complexes showed charac-
teristic peaks for ligand protons (Table 2). The methyl
singlet of the 4-MeC6H4COSe group is unchanged on
replacing palladium by platinum in analogous com-
plexes. However, the methyl resonance is deshielded by
ꢁ0.1 ppm in trans isomer (e.g., [M(SeCOC6H4Me-4)2
(PnPr3)2] d 2.36 ppm) from its position for the cis prod-
ucts (e.g., [M(SeCOC6H4Me-4)2(P\P)] d 2.25 ppm).
The 31P{1H} NMR spectra exhibited a single resonance
suggesting the formation of only one isomeric species.
The magnitude of 1J(Pt–P) is considerably reduced from
the values for the corresponding [PtCl2(PR3)2], indicat-
ing that the phosphine is trans to the Se atom [10,31]. Sel-
enolate ligand in palladium and platinum complexes
have been shown to have comparable trans influence to
that of tertiary phosphines [10].
The cis-chalcogenolate complexes of the type
[M(ER)2(P\P)] (M = Pd or Pt; E = S, Se; P\P = dppm,
dppe) [10,12,16,32] have been used to prepare bi- and
tri-nuclear complexes. Thus, the reaction of [Pd(SeC-
OAr)2(dppe)] (Ar = Ph or 4-MeC6H4) with PdCl2(dppe)
in the presence of NaBPh4 was carried out (Scheme 1).
Both the reactions led to the formation of a single
isolable product, as shown by identical spectroscopic
and analytical data, and has been characterized as
Carbonyl stretching absorptions for mononuclear
complexes appear in
a narrow range of 1610–
1630 cmꢀ1 which appear at lower wave numbers from
the corresponding free acids (mC@O: 1694 (PhCOSeH)
and 1692 (4-MeC6H4COSeH) cmꢀ1) [28] and organic es-
ters (1660–1720 cmꢀ1) [29]. However, these absorptions
appear considerably at higher wave numbers than those
of their potassium salts (ꢁ1538 cmꢀ1) [18,29]. The ob-
served CO absorption indicates that these complexes
contain unidentate ArCOSe ligand [27]. Subtle differ-
ences in the CO absorptions of palladium and platinum
complexes reported here are evident from Table 1. With-
in a series, absorption for the cis isomer appears at lower
wave numbers than that for the trans form. Carbonyl
absorption for palladium complexes is observed at lower
wave number than the corresponding platinum deriva-
tives. Such lowering of carbonyl absorption may be
attributed to weaker M–Se linkage in cis isomers due
to a strong trans influence of the phosphine (trans to
Se) in palladium complexes as compared to the corre-
sponding platinum derivatives. The low value of mCO
stretchings in alkali metal salts has been interpreted in
terms of conjugation (Se–C@O M Se@C–O) leading to
lengthening of carbon–oxygen bond. Formation of
O
Ar
Se
Se
Cl
Cl
P
P
P
P
+
2ArCOSeK
M
M
Ar
O
(M = Pd or Pt; Ar = Ph or C6H4Me-4;
P P = dppm, dppe, dppp)
PdCl (dppe) + 2NaBPh
2
4
(M = Pd, P P = dppe)
P
P
Pd
Se
[BPh ]
4 2
Se
P
P
Pd
Pd
P
P
Scheme 1.

L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
411
Table 1
Physical, analytical, IR and UV–Vis spectral data for Pd(II) and Pt(II) complexes of selenocarboxylate
Complex
% Yield of
recrystallized
productA
Colour
m.p. % Analyses
(ꢀC) (calculated)
mC@O IR
UV–Vis in CH2Cl2, kmax
absorption (e in the order of 104)
in cmꢀ1
C
H
[Pd(SeCOPh)2(dppm)]
[Pd(SeCOPh)2(dppe)]
[Pd(SeCOPh)2(dppp)]
[Pd(SeCOPh)2(PnPr3)2]
[Pd(SeCOC6H4Me-4)2(dppm)]
[Pd(SeCOC6H4Me-4)2(dppe)]
[Pd(SeCOC6H4Me-4)2(dppp)]
[Pd(SeCOC6H4Me-4)2(PnPr3)2]
[Pt(SeCOPh)2(dppm)]
(80)
(57)
(64)
(87)
(44)
(59)
(55)
(93)
(66)
(72)
(58)
(61)
(51)
(54)
(50)
(53)
(69)
(80)
orange-yellow 176
53.9 (54.5) 3.8 (3.7) 1619
54.0 (55.0) 3.6 (3.9) 1609
55.4 (55.5) 3.9 (4.1) 1614
48.1 (48.3) 6.9 (6.6) 1626
55.5 (55.5) 4.3 (4.1) 1623, 1601 247 (5.2), 285 (3.4), 312 (3.2)
56.8 (56.0) 4.8 (4.2) 1614, 1601 244 (5.1), 276 (3.6), 344 (1.8)
55.9 (56.4) 5.1 (4.4) 1614, 1601 245 (5.1), 306 (2.4), 346 (1.5)
48.7 (49.6) 7.1 (6.9) 1621, 1599 247 (5.0), 302 (2.6), 336 (2.4)
48.7 (49.4) 3.2 (3.4) 1626
49.1 (49.9) 3.2 (3.6) 1617
51.3 (50.5) 3.6 (3.7) 1614
43.5 (43.5) 5.9 (5.9) 1630
50.4 (50.5) 3.4 (3.7) 1628, 1601 252 (5.7), 346 (1.2)
50.4 (51.0) 3.6 (3.9) 1623, 1601 248 (7.1), 335 (1.6)
51.3 (51.4) 4.4 (4.0) 1619, 1600 248 (6.8), 341 (1.3)
44.5 (44.8) 6.5 (6.2) 1626, 1599 250 (6.2), 339 (1.5)
229 (6.1), 279 (3.2), 310 (3.0)
274 (3.7), 342 (1.8)
275 (2.1), 309 (1.7), 353 (1.0)
247 (5.0), 302 (2.6), 336 (2.4)
orange-red
orange-red
yellow
182
161
162
180
167
196
174
207
182
171
166
198
200
206
176
306
63
red
orange-red
orange
yellow
yellow
yellow
242 (7.7), 347 (1.5)
241 (6.1), 337 (1.1)
241 (7.8), 346 (1.5)
236 (5.9), 341 (1.2)
[Pt(SeCOPh)2(dppe)]
[Pt(SeCOPh)2(dppp)]
[Pt(SeCOPh)2(PnPr3)2]
yellow
yellow
[Pt(SeCOC6H4Me-4)2(dppm)]
[Pt(SeCOC6H4Me-4)2(dppe)]
[Pt(SeCOC6H4Me-4)2(dppp)]
[Pt(SeCOC6H4Me-4)2(PnPr3)2]
[Pd3(l3-Se)2(dppe)3][BPh4]2 Æ CH2Cl2
[PdCl(SeCOPh)(PnPr3)2]
A
yellow
yellow
yellow
yellow
a
orange-red
orange
62.9 (63.6) 4.7 (4.8)
46.4 (46.4) 7.2 (7.3) 1622, 1575 247 (3.4), 323 (1.3)
275 (4.6), 304 (3.6), 361 (2.3)
All complexes were recrystallized from a CH2Cl2–haxane mixture.
Se: Found 6.7%; Calc. 6.8% (analysed by GFAAS).
a
[Pd3(l3-Se)2(dppe)3][BPh4]2. The IR spectra were devoid
90ꢀ. The asymmetric disposition of selenocarboxylate li-
gands may be due to an attractive non-bonded interac-
tion between O1 and Se2 rather than steric factors.
Existence of attractive non-bonded Seꢂ ꢂ ꢂO interactions
has been reported recently by Komatsu et al. [35].
of carbonyl stretching band in the region 1600–
1
1700 cmꢀ1. Similarly, the H NMR spectra of the prod-
ucts from both the reactions were identical. The spectra
did not show resonances attributable to aryl protons of
COSeAr group. The 31P{1H} NMR spectra exhibited a
peak at d 50.5 (CDCl3) ppm. This chemical shift can be
compared with the shift reported for [Pd3(l3-
S)2(dppe)3]2+ d 52.9 (DMSO). The later is easily prepared
by the reaction of PdCl2(dppe) with an excess of
Na2S Æ 9H2O [33].
˚
However, the Se1ꢂ ꢂ ꢂO1 distance 3.47(3) A is somewhat
˚
longer in the present case than the distances (ꢁ3.1 A)
dealt by Komatsu et al. [35]. The six membered
‘‘PtPC3P’’ ring is puckered. The C@O, C–Se, Pt–P bond
distances are as expected [18,26–28,36].
2.3. Thermal studies
2.2. Structure of [Pt(SeCOPh)2(dppp)]
Thermogravimetric analyses of [Pd(SeCOPh)2(dppe)]
and [Pd(SeCOPh)2(PnPr3)2] were carried out under flow-
ing argon atmosphere. The former complex showed a
complex decomposition pattern with the formation of a
mixture of palladium selenides. Heating this complex in
a furnace at 500 ꢀC also gave a mixture of palladium sel-
enides as established by XRD data and showed consider-
able carbon contamination (Found: C = 5.7; H < 0.2%).
The TG curve (Fig. 2) of trans-[Pd(SeCOPh)2
(PnPr3)2] showed a single step decomposition route with
the formation of Pd17Se15 at 240 ꢀC as inferred from
weight loss (Found: 81%, Calc.: 78%). To prepare large
quantities of the later, pyrolysis was carried out as a solid
in a furnace and also in TBP solution. Furnace heating at
350 ꢀC of the complex yielded the single phase Pd17Se15
as inferred from weight loss and confirmed by XRD
data.1 Decomposition in TBP at 200 ꢀC also afforded
The molecular structure of [Pt(SeCOPh)2(dppp)] has
been established by single crystal X-ray diffraction anal-
ysis. The ORTEP [34] with atomic numbering scheme is
shown in Fig. 1 and selected bond lengths and angles are
given in Table 3. The structure shows that the platinum
atom is in a distorted square planar environment. Coor-
dination around platinum is defined by chelating dppp
moiety and two unidentate selenobenzoate ligands
bonded through selenium atom only with carbonyl oxy-
gens lying away from the metal square plane. This con-
figuration is previously reported for Pd/Pt
chalcogenolate complexes [M(SeR)2(P\P)] [10]. The
two selenobenzoate ligands are not symmetrically
disposed with respect to the dppp moiety as the two
˚
Pt–Se distances are significantly different (0.02 A). The
oxygen (O1) of one of the ligands is pointing towards
the selenium (Se2) of the other selenocarboxylate. The
Se1–Pt–Se2 angle (81.37(4)ꢀ) deviates considerably from
1
JCPDS-ICDD 29-1437.

412
L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
Table 2
1H and 31P{1H} NMR data for Pd(II) and Pt(II) complexes of selenocarboxylate
Complex
31P{1H} NMR
1H NMR, d in ppm
d in
1J(Pt–P)
ppm
(Hz)
[Pd(SeCOPh)2(dppm)]
[Pd(SeCOPh)2(dppe)]
ꢀ38.2
4.16 (t, 8.6 Hz, 2H, P–CH2); 7.16–7.34 (m), 7.73–7.80 (m) [30H, COPh + P–Ph]
2.24, 2.35 (d, m, 14.0 Hz, 4H, P–CH2); 7.11–7.18 (m), 7.42 (br, m), 7.67–7.87 (m) [30H,
Ph]
55.9
[Pd(SeCOPh)2(dppp)]
[Pd(SeCOPh)2(PnPr3)2]
3.2
4.7
2.01 (br, 2H, PCH2CH2); 2.55 (br, 4H, P–CH2); 7.10–7.29 (m, br), 7.73 (m) [30H, Ph]
0.95 (t, 7.2 Hz, 18H, PCH2CH2Me); 1.57 (m, 12H, PCH2CH2); 1.97 (m, 12H, P–CH2);
7.34–7.51 (m), 8.05 (d, 7.0 Hz) [10H, Ph]
[Pd(SeCOC6H4Me-4)2(dppm)]
[Pd(SeCOC6H4Me-4)2(dppe)]
ꢀ38.6
2.27 (s, 6H, C6H4Me); 4.14 (t, 8.0 Hz, 2H, P–CH2); 7.00 (d, 8.7 Hz, 4H), 7.67 (d, 8.2 Hz,
4H) [C6H4]; 7.28–7.37 (m), 7.75–7.85 (m) [20H, Ph]
2.25 (s, 6H, C6H4Me); 2.24, 2.34 (d, m, 4H, P–CH2 one of the multiplets merged with
C6H4Me peak); 6.94 (d, 8.2 Hz, 4H), 7.60 (d, 8.2 Hz, 4H)[C6H4]; 7.39 (m), 7.79-7.87 (m)
[20H, Ph]
55.2
[Pd(SeCOC6H4Me-4)2(dppp)]
[Pd(SeCOC6H4Me-4)2(PnPr3)2]
[Pt(SeCOPh)2(dppm)]
2.4
4.6
2.02 (br, 2H, PCH2CH2); 2.24 (s, 6H, C6H4Me); 2.55 (br, 4H, P–CH2); 6.93 (d, 8.0 Hz,
4H), 7.63 (d, 8.0 Hz, 4H)[C6H4]; 7.29 (m), 7.70–7.83 (m) [20H, Ph]
0.94 (t, 7.0 Hz, 18H, PCH2CH2Me); 1.57 (m, 12H, PCH2CH2); 1.97 (m, 12H, P–CH2);
2.36 (s, 6H, C6H4Me); 7.17 (d, 8.2 Hz, 4H), 7.96 (d, 8.0 Hz, 4H) [C6H4]
4.46 (t, 10.0 Hz, J(Pt–H) = 59 Hz, 2H, P–CH2); 7.17–7.35 (m), 7.71–7.85 (m) [30H,
COPh + P–Ph]
2.18 (d, 19.0 Hz, 4H, P–CH2 with Pt satellites); 7.12–7.42 (m), 7.70 (d, 7.2 Hz) (10H,
COPh)]; 7.80–7.89 (m) [20H, Ph]
2.00 (br, 2H, PCH2CH2); 2.57 (br, 4H, P–CH2); 7.14 (t, 7.7 Hz), 7.70 (d, 7.8 Hz), [10H,
CO Ph]; 7.33 (br), 7.81(br) [20H, Ph]
ꢀ48.7
47.1
2726
3028
2882
2426
2733
3030
2882
2433
[Pt(SeCOPh)2(dppe)]
[Pt(SeCOPh)2(dppp)]
ꢀ4.8
ꢀ0.8
ꢀ49.3
47.1
[Pt(SeCOPh)2(PnPr3)2]
0.96 (t, 7.2 Hz, 18H, PCH2CH2Me); 1.59 (br, 12H, PCH2CH2); 2.03 (m, 12H, P–CH2);
7.33–7.51(m), 8.02 (d, 7.0 Hz) [10H, Ph]
[Pt(SeCOC6H4Me-4)2(dppm)]
[Pt(SeCOC6H4Me-4)2(dppe)]
[Pt(SeCOC6H4Me-4)2(dppp)]
[Pt(SeCOC6H4Me-4)2(PnPr3)2]
2.27 (s, 6H, C6H4Me); 4.44 (t, 9.8 Hz, J(Pt–H) = 60 Hz), 2H, P–CH2–P; 7.00 (d, 8.0 Hz,
4H), 7.66 (d, 8.0 Hz, 4H) [C6H4]; 7.33 (m), 7.86 (m) [20H, Ph]
2.25 (s, 6H, C6H4Me); 2.12, 2.21(d, m, 18.8 Hz, 4H, P–CH2 with Pt satellites); 6.96 (d,
8.0 Hz, 4H), 7.62 (d, 8.0 Hz, 4H)[C6H4]; 7.40 (m), 7.85–7.89 (m) [20H, Ph]
2.00 (m, 2H, PCH2CH2); 2.23 (s, 6H, C6H4Me); 2.56 (br, 4H, P–CH2); 6.90 (d, 8.0 Hz,
4H), 7.60 (d, 8.0 Hz, 4H) [C6H4]; 7.26–7.31 (m), 7.70–7.82 (br) [20H, Ph]
0.95 (t, 7.0 Hz, 18H, PCH2CH2Me); 1.58 (m, 12H, PCH2CH2); 2.01 (m, 12H, P–CH2);
2.36 (s, 6H, C6H4Me); 7.17 (d, 8.0 Hz, 4H), 7.93 (d, 8.2 Hz, 4H) [C6H4]
2.15, 2.26 (br, s, 12H, PCH2); 6.77–7.47 (m, 100H, Ph)
ꢀ5.5
ꢀ0.8
a
[Pd3(l3-Se)2(dppe)3][BPh4]2
50.5
7.7
[PdCl(SeCOPh) (PnPr3)2]
1.00 (t, 10.6 Hz, 18H, PCH2CH2Me); 1.55–1.65 (m, 12H, PCH2CH2); 1.86–1.94 (m,
12H, P–CH2); 7.26–7.53 (m), 7.99 (m) [5H, Ph]
a
Recorded in CD2Cl2.
Pd17Se15 which, however, showed a considerably broad-
ening of XRD pattern (Fig. 3) as compared to the bulk
material. Broadening of the XRD pattern suggests that
the particles are in a nanometer regime.
Although palladium and platinum selenocarboxylates
are structurally and spectroscopically similar to the
[M(SeAr)2(P\P)] (M = Pd or Pt) complexes, the reactiv-
ity is remarkably different and may serve as a convenient
source for selenium atom transfer. This is demonstrated
by isolation of [Pd3(l3-Se)2(dppe)3]2+ and low tempera-
ture synthesis of Pd17Se15.
3. Experimental
Palladium and platinum complexes, MCl2(P\P)
(M = Pd or Pt; P\P = dppm, dppe, dppp) and trans-
MCl2(PnPr3)2 [37,38], potassium monoselenobenzoate
Fig. 1. Molecular structure of [Pt(SeCOPh)2(dppp)] with crystallo-
graphic numbering scheme.
(KSeCOPh) [Anal. Calc.: C, 37.7; H, 2.3. Found: C,

L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
413
Table 3
Selected bond lengths (A) and angles (ꢀ) for [Pt(SeCOPh)2(dppp)]
100
˚
Pt–Se(1)
Pt–Se(2)
Pt–P(1)
Pt–P(2)
2.4821(11)
80
60
40
20
2.4613(10)
2.277(2)
2.280(2)
1.876(9)
1.214(11)
1.894(10)
1.214(11)
1.835(9)
1.807(10)
1.827(8)
1.834(9)
1.794(9)
1.817(10)
1.535(12)
1.542(12)
C(1)–Se(1)
C(1)–O(1)
C(8)–Se(2)
C(8)–O(2)
P(1)–C(15)
P(1)–C(21)
P(1)–C(27)
P(2)–C(29)
P(2)–C(36)
P(2)–C(30)
C(28)–C(29)
C(27)–C(28)
0
30
40
50
60
a
Angle (2θ)
100
80
60
40
20
Se(1)–Pt–Se(2)
P(1)–Pt–P(2)
Se(1)–Pt–P(1)
Se(1)–Pt–P(2)
Se(2)–Pt–P(1)
81.37(4)
94.24(8)
172.24(7)
87.01(7)
97.11(6)
168.32(6)
125.3(8)
120.2(8)
114.6(7)
123.7(7)
119.3(9)
117.1(7)
114.5(3)
117.1(3)
113.5(3)
118.5(3)
113.0(3)
112.9(3)
114.0(6)
111.4(8)
113.6(6)
Se(2)–Pt–P(2)
Se(1)–C(1)–O(1)
C(2)–C(1)–O(1)
C(2)–C(1)–Se(1)
Se(2)–C(8)–O(2)
C(9)–C(8)–O(2)
C(9)–C(8)–Se(2)
Pt–P(1)–C(15)
Pt–P(1)–C(21)
Pt–P(1)–C(27)
Pt–P(2)–C(29)
Pt–P(2)–C(30)
Pt–P(2)–C(36)
P(1)–C(27)–C(28)
C(27)–C(28)–C(29)
C(28)–C(29)–P(2)
30
40
50
60
b
Angle (2θ)
Fig. 3. XRD for Pd17Se15 obtained from decomposition of [Pd(Se-
COPh)2(PnPr3)2] in (a) furnace (b) TBP.
Me-4) [Anal. Calc.: C, 40.3; H, 3.4. Found: C, 40.4; H,
3.2%. IR(KBr): mC@O = 1534 cmꢀ1. 1H NMR (CD3OD)
d: 2.32 (s, Me); 7.10 (d, 8 Hz), 8.01 (d, 8.2 Hz) (C6H4)]
[18,19,39] were prepared according to the literature
methods. All reactions were carried out under an inert
atmosphere (N2 or Ar) using Schlenk techniques. Sol-
vents were dried and distilled before use. All the newly
reported complexes were crystallized from a CH2Cl2–
hexane mixture.
0
-20
-40
UV–Vis absorption spectra were recorded in CH2Cl2
on a Varian Cary 500 scan spectrophotometer. IR spec-
tra were recorded as KBr pallets on a JASCO 610 FT-IR
spectrometer. Microanalyses were carried out on a Ea-
-60
-80
1
ger 300 EA 1112 instrument. H NMR spectra were re-
-100
corded on a Bruker AC-200 MHz spectrometer and
chemical shifts are relative to the internal chloroform
peak (d 7.26 ppm). 31P{1H} NMR were recorded on a
Bruker DPX-300 NMR spectrometer. TG-DT curves
were obtained at a heating rate of 10 ꢀC minꢀ1 under
flowing argon on a Setaram 92-16.18 instrument. Pow-
der XRD patterns were recorded on a Philips PW
1710 using Cu Ka radiation.
100
200
300
Temperature (˚C)
Fig. 2. TG curve of [Pd(SeCOPh)2(PnPr3)2].
37.1; H, 2.5%. IR(KBr): mC@O = 1538 cmꢀ1. H NMR
(CD3OD) d: 7.25–7.48 (m), 8.07–8.10 (m) (Ph)] and
potassium p-tolylmonoselenocarboxylate (KSeCOC6H4-
1

414
L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
3.1. Preparation of [Pd(SeCOC6H4Me-4)2(dppm)]
To dichloromethane suspension (7 ml) of
trated and few drops of hexane were added. On cooling
orange red crystals of the title compound were obtained.
Following analogous procedure, title complex could also
be obtained from [Pd(SeCOC6H4Me-4)2(dppe)] with the
comparable yield.
a
PdCl2(dppm) (117 mg, 0.21 mmol), a methanolic solu-
tion (10 ml) of KSeCOC6H4Me-4 (110 mg, 0.46 mmol)
was added with stirring, whereupon a clear orange-red
solution was formed. The reaction mixture was stirred
for 1.5 h. After stripping off the solvents under reduced
pressure, contents were extracted with dichloromethane
and passed through a Florisil column (0.7 · 5 cm). The
orange solution thus obtained was concentrated and
few drops of hexane were added which on cooling gave
orange-red crystals. Similarly, complexes [M(Se-
COAr)2(P\P)] (M = Pd or Pt; P\P = dppm, dppe, dppp;
Ar = Ph, 4-MeC6H4) were prepared. Analytical data are
given in Table 1.
3.5. Thermal decomposition of [Pd(SeCOPh)2(PnPr3)2]
(i) The complex [Pd(SeCOPh)2(PnPr3)2] (202 mg,
0.25 mmol) in a silica boat was kept inside a quartz tube.
Whole assembly was housed in a furnace and heated at
350 ꢀC under flowing argon atmosphere for 4 h. The
black residue thus obtained (Found: 41 mg, Calc. for
Pd17Se15 = 44 mg) in the silica boat was identified as
Pd17Se15 from XRD data (JCPDS file No.: 29-1437)
(Found: C = 1.9; H < 0.2%). Similarly, [Pd(Se-
COPh)2(dppe)] (136 mg) was pyrolysed at 500 ꢀC in a
furnace to give a black residue (23 mg).
3.2. Preparation of [Pt(SeCOPh)2(PnPr3)2]
(ii) A tri-n-butylphosphate solution (10 cm3) of
[Pd(SeCOPh)2(PnPr3)2] (151 mg, 0.19 mmol) was heated
at 200 ꢀC with stirring for 1.5 h under argon atmosphere
whereupon a black fine powder was separated. This was
filtered through G-3 filter, washed with benzene
(2 · 2 cm3) followed by hexane (4 · 2 cm3) and dried to
A methanolic solution (10 ml) of KSeCOPh (119 mg,
0.53 mmol) was added to a dichloromethane solution
(10 ml) of PtCl2(PnPr3)2 (140 mg, 0.24 mmol). Reaction
mixture was stirred for 2 h. After removal of solvent
in vacuo, the residue was extracted with dichlorometh-
ane to give a yellow solution which was subsequently
passed through a Florisil column (0.7 · 5 cm) and con-
centrated. To the concentrate few drops of hexane were
added and the solution on cooling at ꢀ5 ꢀC gave yellow
crystals of [Pt(SeCOPh)2(PnPr3)2]. Complexes [M(SeC-
OAr)2(PnPr3)2] (where M = Pd, Pt; Ar = Ph, C6H4Me-
4) were prepared in a similar manner (see Table 1).
yield
a black powder (Found: 31 mg, Calc. for
Pd17Se15 = 33 mg) identified as Pd17Se15 from XRD
data (Table 4) (JCPDS file No.: 29-1437) (Found:
C = 1.8; H < 0.2%).
3.6. Crystallography
X-ray data on yellow crystals of [Pt(SeCOPh)2(dppp)]
were collected at room temperature with an Enraf-Non-
ius CAD-4 diffractometer using graphite-monochro-
3.3. Preparation of [PdCl(SeCOPh)(PnPr3)2]
A dichloromethane solution (5 ml) of PdCl2(PnPr3)2
(60 mg, 0.12 mmol) was added to Pd(SeCOPh)2(PnPr3)2
(96 mg, 0.12 mmol) solution in the same solvent (10 ml).
Resulting orange solution was stirred for 1 h. The sol-
vent was stripped off in vacuo and the contents were ex-
tracted with dichloromethane and filtered. The filtrate
was reduced to 3 cm3 by evaporating solvent under re-
duced pressure. Addition of hexane to the solution
and cooling at ꢀ5 ꢀC led to orange crystals.
mated Mo Ka radiation (k = 0.71073 A), employing
˚
the x–2h scan technique. Crystal data are given in
Table 5. The unit cell parameters were determined from
25 reflections measured by random search routine and
indexed by the method of short vectors followed by least
Table 4
XRD data on Pd17Se15 obtained from [Pd(SeCOPh)2(PnPr3)2] (inten-
sity greater than 20%)
a
˚
˚
d in A (experimental)
d in A (reported)
Furnace heating
TBP heating
3.4. Preparation of [Pd3(l3-Se)2(dppe)3][BPh4]2
3.35
3.19
2.94
2.83
2.57
2.50
2.43
2.36
2.31
2.03
1.87
1.77
3.35
3.19
3.35
3.20
2.94
2.83
2.57
2.50
2.43
2.37
2.31
2.04
1.87
1.77
A
mixture of [Pd(SeCOPh)2(dppe)] (82 mg,
0.09 mmol) and PdCl2(dppe) (54 mg, 0.09 mmol)
(31P{1H} NMR in CDCl3 d: 64.9 ppm) in dichlorometh-
ane (12 ml) containing few drops of methanol was stirred
for 30 min. To the resulting red solution, a methanolic
solution (10 ml) of NaBPh4 (64 mg, 0.19 mmol) was
added and the reaction mixture was further stirred for
30 min. The solvents were removed in vacuo and the res-
idue was extracted with dichloromethane. Extract was
passed through a Florisil column (0.7 · 5 cm), concen-
2.83
2.57
2.49
2.42
2.36
2.31
2.03
1.87
1.76
a
JCPDS-ICDD 29-1437.

L.B. Kumbhare et al. / Inorganica Chimica Acta 359 (2006) 409–416
415
Table 5
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121.
Crystallographic and structure refinement details for [Pt(SeCOPh)2
(dppp)]
[4] M.A. Ansari, J.A. Ibers, Coord. Chem. Rev. 100 (1990) 223.
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Trans. (1991) 759.
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[9] J. Real, M. Pages, A. Polo, J.F. Piniella, A. Alvarez-Larena,
Chem. Commun. (1999) 277.
Empirical formula
Formula mass
C41H36O2P2PtSe2
975.65
0.2 · 0.2 · 0.1 (yellow)
293 (2)
0.71073
Crystal size (mm3) (colour)
T (K)
˚
k (A)
Crystal system
Space group
Unit cell dimensions
monoclinic
P21/c
[10] (a) A. Singhal, V.K. Jain, B. Varghese, E.R.T. Tiekink, Inorg.
Chim. Acta 285 (1999) 190;
˚
a (A)
14.400 (3)
18.8248 (17)
15.022 (3)
114.999 (16)
3690.5 (11)
1.756
(b) N.K. Lokanath, H.C. Devarajegowda, S.M. Anandalwar, S.J.
Prasad, S. Narayan, V.K. Jain, Anal. Sci. 17 (2001) 565.
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Chim. Acta 357 (2004) 2134.
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10 (2000) 1121.
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48.
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Kaim, J. Chem. Soc., Dalton Trans. (2001) 723.
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Eur. J. Inorg. Chem. (2003) 744.
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Chem. Soc. Jpn. 68 (1995) 3507.
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[19] O. Niyomura, K. Tami, S. Kato, Heteroatom Chem. 10 (1999)
373.
[20] T. Kanda, K. Mizoguchi, T. Koike, T. Murai, S. Kato, Synthesis
(1994) 282.
˚
b (A)
˚
c (A)
b (ꢀ)
3
˚
V (A )
qcald (Mg mꢀ3
)
Z
4
l (mmꢀ1
)
5.896
2.16–24.97
h for data collection (ꢀ)
Reflection collected/unique reflections 7742/6475
Refinement method
Absorption correction
Data/restraints/parameters
Goodness-of-fit on F2
Final R1, xR2 indices
R1, xR2 (all data)
full matrix least square on F2
w-scan
6475/0/433
1.021
0.0428, 0.0950
0.0950, 0.1134
square refinements. The intensity data were corrected
for Lorentz, polarization and absorption effects. The
structure was solved using SIR92 [40] and using
SHELXL97 [41] computer programs. The non-hydrogen
atoms were refined anisotropically.
[21] H. Ishihara, Y. Hirabayashi, Chem. Lett. (1976) 203.
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Trans. I (1994) 1083.
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Naturforsch. 47 (1992) 558.
[24] H. Ishihara, S. Muto, T. Endo, M. Komada, S. Kato, Synthesis
(1989) 929.
4. Supplementary material
[25] S. Kato, H. Ishihara, K. Ibi, H. Kageyama, T. Murai, J.
Organomet. Chem. 386 (1990) 313.
[26] M.T. Ng, P.A.W. Dean, J.J. Vittal, Dalton Trans. (2004) 2890.
[27] Y. Kawahara, S. Kato, T. Kanda, T. Murai, K. Miki, J. Chem.
Soc., Dalton Trans. (1996) 79.
CCDC No. 273317 contains Supplementary Crystal-
lographic Data for this paper. The data can be obtained
free of charge at www.ccdc.cam.ac.uk/conts/retriev-
ing.html or from the Cambridge Crystallographic data
Center, 12 Union Road, Cambridge CB 2, 1 EZ, UK.
[28] H. Kageyama, T. Murai, T. Kanda, S. Kato, J. Am. Chem. Soc.
116 (1994) 2195.
[29] Y. Kawahara, S. Kato, T. Kanda, T. Murai, Bull. Chem. Soc.
Jpn. 67 (1994) 1881.
[30] J. van Slageren, A. Klein, S. Zalis, Coord. Chem. Rev. 230 (2002)
193.
Acknowledgements
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85.
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Dalton Trans. (1993) 1509.
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gram for crystal structure illustrations, ORNL-5138, 1976.
[35] H. Komatsu, M. Iwaoka, S. Tomoda, Chem. Commun. (1999)
205.
Authors are grateful to Dr. T. Mukharjee and Dr.
S.K. Kulshreshtha for encouragement of this work. We
thank Dr. L.P. Badheka, Bio-organic Division, BARC
for assisting in recording NMR spectra. Authors thank
Heads, Analytical Chemistry and Fuel Chemistry Divi-
sions, BARC for providing microanalysis and IR data,
respectively. We thank DST-FIST facility at Madurai
Kamraj University, Madurai for X-ray data collection.
[36] S. Dey, V.K. Jain, A. Knoedler, W. Kaim, S. Zalis, Eur. J. Inorg.
Chem. (2001) 2965.
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