Heterodimetallic PdII-based carboxylate-bridged complexes: Synthesis and structure of single-crystalline PdII-M (M = MnII, CoII, NiII, CuII, ZnII, NdIII, EuIII, CeIV) acetates

Article abstract of DOI:10.1016/j.ica.2006.01.027

A series of crystalline Pd^II-based heterodimetallic acetate-bridged complexes containing the transition (Mn^II, Co^II, Ni^II, Cu^II), post-transition (Zn^II) and rare-earth (Ce^IV, Nd^III, Eu^III) metals were synthesized starting from Pd₃(OOCMe)₆ and the complementary metal(II, III) acetates. The crystal and molecular structures of the binuclear Pd^IIM^II(μ-OOCMe)₄L (M = Mn, Co, Ni, Zn; L = H₂O, MeCN), trinuclear multiscripts(Pd, 2, mml:none(), mml:none(), II) Cu^II ( μ - OOCMe )₆ and tetranuclear {Mathematical expression} (M = Nd, Eu) and {Mathematical expression} complexes were established by X-ray diffraction.

Full text of DOI:10.1016/j.ica.2006.01.027

Inorganica Chimica Acta 359 (2006) 2072–2086
www.elsevier.com/locate/ica
Heterodimetallic PdII-based carboxylate-bridged complexes:
Synthesis and structure of single-crystalline PdII–M
(M = MnII, CoII, NiII, CuII, ZnII, NdIII, EuIII, CeIV) acetates
a
a
b
Natalia Yu. Kozitsyna , Sergei E. Nefedov , Fedor M. Dolgushin ,
a
a,
a
Natalia V. Cherkashina , Michael N. Vargaftik *, Ilya I. Moiseev
a
N.S. Kurnakov Institute of General and Inorganic Chemistry, Coordination Chemistry, Leninski Prospect, 31, Russian Academy of Sciences,
119991 Moscow, Russian Federation
b
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russian Federation
Received 26 September 2005; accepted 10 January 2006
Available online 9 March 2006
Dedicated to Professor Brian James in recognition of his pioneering contribution to homogeneous catalysis and inorganic chemistry.
Abstract
A series of crystalline PdII-based heterodimetallic acetate-bridged complexes containing the transition (MnII, CoII, NiII, CuII), post-
transition (ZnII) and rare-earth (CeIV, NdIII, EuIII) metals were synthesized starting from Pd3(OOCMe)6 and the complementary
metal(II, III) acetates. The crystal and molecular structures of the binuclear PdIIMII(l-OOCMe)4L (M = Mn, Co, Ni, Zn; L = H2O,
II
MeCN), trinuclear Pd2IICu ðl-OOCMeÞ6 and tetranuclear Pd2IIM2 ðl;g2-OOCMeÞ2ðl-OOCMeÞ8ðTHFÞ2 (M = Nd, Eu) and
III
Pd2IICe2 ðl;g2-OOCMeÞ2ðg1-OOCMeÞ2ðl-OOCMeÞ8ðH2OÞ2 complexes were established by X-ray diffraction.
IV
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Palladium(II); Heterodimetallic complexes; 3d-Metals; 4f-Metals; Synthesis; Crystal structures
1. Introduction
catalysts, organosoluble PdII-based heterometallic com-
plexes with easily removable carboxylate ligands (acetate,
pivalate, etc.) show considerable promise.
Palladium-based heterometallic complexes are of both
academic and practical interest, particularly as promising
precursors of mixed-metal catalysts [1]. Typical examples
are bimetallic Pd–Co catalysts for alkene hydroformylation
[2,3] and fuel cells [4,5] and Pd–Cu catalysts for selective
olefin oxidation [6–12]. Meanwhile, only few structurally
characterized PdII-transition metal complexes have been
documented, for example [13–16], mostly containing halide
bridges and/or organic N- and P-donor ligands, which can
pose difficulties in the preparation of metallic nanoparti-
cles. In view of the synthesis of Pd-transition metal cluster
Several PdII-based heterodimetallic purely acetate com-
plexes, PdCo(OAc)4 Æ 2HOAc Æ 2H2O, PdNi(OAc)4 Æ HOA-
c Æ H2O, PdCu(OAc)4, PdCd(OAc)4 Æ H2O Æ HOAc, etc.,
were synthesized as early as 1968 [17]; however, the molec-
ular structures of these compounds are still unknown. We
found in the CSD only two records for the X-ray structures
of carboxylate PdII-based heterometallic complexes with
post-transition metals, PdTl(l-OOCMe)4(OOCMe) [18]
and Pd2Cd2(l-OOCMe)8 Æ (HOOCMe)2 [19] but none of
the PdII-based acetate complexes with transition and
rear-earth metals.
Palladium(II) acetate Pd3(l-OOCMe)6 is a convenient
starting compound for the synthesis of such complexes.
The trinuclear cyclic structure of this complex is stable
*
Corresponding author. Tel.: +7 095 9554865; fax: +7 095 9541279.
E-mail address: mvar@igic.ras.ru (M.N. Vargaftik).
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2006.01.027

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2073
and poorly reactive but is readily cleaved by nucleophilic
2. Experimental
agents such as alkaline, NR4 or [(Ph3P)2N]+ acetates
þ
[20–23]. The coordination vacancies that arose in the PdII
square-plane upon the acetate bridge splitting are filled
with additional acetate ligands, producing the binuclear
[Pd2(OCOMe)6]2ꢀ and mononuclear [Pd(OCOMe)4]2ꢀ
anionic complexes:
2.1. Reagents and physical measurements
Solvents (glacial acetic acid, acetonitrile, tetrahydrofu-
rane, benzene, n-hexane and n-pentane (all reagent grade,
Reakhim, Russia)) were purified by standard procedures
[24].
2ꢀ
2Pd3ðOOCMeÞ þ 6MþMeCOOꢀ ꢀ3Mþ½Pd2ðOOCMeÞ ꢁ
;
6
2
6
Palladium(II) acetate Pd3(OOCMe)6 was prepared by
the oxidation of Pd black (prepared by reduction of PdCl2
(reagent grade, Reakhim, Russia), with NaBH4) with con-
centrated HNO3 in glacial acetic acid by a known proce-
dure [25]. The raw reaction product was purified from the
admixture of PdII nitrito complexes by refluxing in glacial
AcOH with a fresh portion of Pd black until NO2 evolution
ceased followed by recrystallization from hot AcOH.
The salts Mn(OOCMe)2 Æ 4H2O, Co(OOCMe)2 Æ 4H2O,
Ni(OOCMe)2 Æ 4H2O, Cu(OOCMe)2 Æ H2O and Zn(OOC-
Me)2 Æ 2H2O (all reagent grade, Acros, Belgium), Ce(OOC-
Me)3 Æ 4H2O, Nd(OOCMe)3 Æ 1.5H2O and Eu(OOCMe)3 Æ
4H2O (all high purity grade, Reakhim, Russia) were used
as received.
The elemental C,H,N analyses were performed on an
automated C,H,N-analyzer (Carlo Erba Strumentazione,
Italy). Single-crystal X-ray diffraction experiments were
carried out on Bruker SMART 1000 CCD and Enraf Non-
ius CAD 4 diffractometers. The IR spectra were recorded
on a Nicolet Nexus spectrometer (KBr pellets). The UV–
Vis spectra were measured on a Varian Cary 100
spectrophotometer.
2ꢀ
2ꢀ
Mþ½Pd2ðOOCMeÞ ꢁ þ 2MþMeCOOꢀ ꢀ2M2þ½PdðOOCMeÞ4ꢁ
;
2
6
Mþ ¼ Naþ;Kþ;NR4þ;½ðPh3PÞ2Nꢁþ
which exist in solution as close ion pairs with the corre-
sponding cations.
Based on analogy with these reactions, the mononuclear
di- and trivalent transition and rare-earth metal acetates
were expected to serve as a source of acetate group per-
forming a nucleophilic attack on the Pd3(l-OOCMe)6
molecule:
Me
Me
C
O
C
O
M
O
O
O
.
.
Pd
O
C
Pd
O
C
Me
O
O
O
C
Me
Me
Pd
O
O
O
C
C
O
Me
Me
Should this be the case, not only the close ion pair but
also a covalently linked mixed-metal complex can be
formed:
2.2. Syntheses
Typically, a slurry of palladium acetate Pd3(OOCMe)6
(448 mg, 2 mmol based on Pd) and the MnII,CoII, NiII,
ZnII, CeIII, NdIII, EuIII (2 mmol) or CuII acetate (1 mmol)
in glacial acetic acid (20 ml) was stirred under reflux until
the salts completely dissolved (ꢂ1.5 h). The reaction solu-
tion was cooled to room temperature, filtered and evapo-
rated to dryness on a rotary evaporator (temperature of
water bath at most 60 ꢁC). Benzene (15 ml) was added to
the residue, evaporated to dryness on a rotary evaporator,
and the procedure was repeated several times to remove
acetic acid, affording in most cases a noncrystalline or
microcrystalline mixed-metal complex. To prepare single-
crystalline samples, the dry residue was treated with differ-
ent solvents depending on the nature of the complementary
metal. As a rule, the single-crystalline complexes contained
the incorporated solvent molecules.
R
C
O
O
Pd
O
OOCR
.
1/3 Pd3(OOCR)6 + M(RCOO)2
M
O
C
R
Based on this approach, we proposed a convenient proto-
col for the synthesis of organosoluble, crystalline PdII-
based heterodimetallic acetate complexes containing no
hard to remove ligands. According to this protocol, we pre-
pared eight single-crystalline complexes involving 3d- and
4f-complementary metals: binuclear PdIIMII(l-OOCMe)4L
(M = Mn, Co, Ni, Zn; L = H2O, MeCN), trinuclear
2.3. PdCo(l-OOCMe)4(NCMe) · 3MeCN (1a) and
PdCo(l-OOCMe)4(NCMe) · 0.5MeCN (1b)
II
III
Pd2IICu ðl-OOCMeÞ6 and tetranuclear Pd2IINd2
-
III
ðl;g2-OOCMeÞ2ðl-OOCMeÞ8ðTHFÞ2,
Pd2IIEu2 ðl;g2-
IV
OOCMeÞ2ðl-OOCMeÞ8ðTHFÞ2
and
Pd2IICe2 ðl;g2-
The pinkish-beige dry residue prepared according to the
general procedure from Pd3(OOCMe)6 (448 mg, 2 mmol
based on Pd(OOCMe)2 unit) and Co(OOCMe)2 Æ 4H2O
(497 mg, 2 mmol) was dissolved in acetonitrile (20 ml),
OOCMeÞ2ðg1-OOCMeÞ2ðl-OOCMeÞ8ðH2OÞ2. The crystal
and molecular structures of the complexes were established
by single-crystal X-ray diffraction.

2074
N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
concentrated to 5 ml on a rotary evaporator, and stored for
crystallization at room temperature. Dark cherry-colored
crystals of complex 1a were precipitated in 2–4 h in a yield
of 520 mg. After the removal of the crystals, the mother
liquor was refrigerated for 24 h to produce 230 mg of smal-
ler crystals of complex 1b. Slow evaporation in air at room
temperature of the rest mother liquor afforded an addi-
tional portion of crystals 1b. Total yield of complexes
1a + 1b was 750 mg (ꢂ85% based on Pd). Complexes 1a
and 1b readily lose the MeCN crystallization molecules in
air at room temperature. Anal. Calc. for C10H15O8NPdCo
(without the MeCN crystallization molecule): C, 27.14; N,
3.16; H, 3.42. Found: C, 27.34; N, 3.23; H 3.49%. IR spec-
trum (KBr, cmꢀ1): 2945m, 2882w, 2822w, 1610s (mas(CO)),
1409s (ms(CO)), 1385w, 1345w, 1051w, 1029w, 698m, 624w.
UV–Vis spectrum (acetic acid): 335 nm (e = 1.6 ·
103 l molꢀ1 cmꢀ1), 260 (e = 3.0 · 103 l molꢀ1 cmꢀ1).
similarly to the synthesis of complex 3 (see above) to pro-
duce 745 mg (75% based on Pd) of the pink crystals of
complex 4. Anal. Calc. for C12H22O10PdZn: C, 28.94; H,
4.45. Found: C, 28.85; H, 4.50%. IR spectrum (KBr, cmꢀ1):
2924m, 2853w, 1595vs, br (mas(CO)), 1397vs (ms(CO)), 1339m,
1049m, 1024m, 933w, 676m, 621w.
2.7. Pd2Nd2(l-OOCMe)8(l,g2-OOCMe)2(THF)2 · 2THF
(5)
The complex was prepared according to the general pro-
cedure starting from Pd3(OOCMe)6 (448 mg, 2 mmol) and
Nd(OOCMe)3 Æ 1.5H2O (690 mg, 2 mmol) and crystalliza-
tion from THF in a yield of 0.68 g. An additional portion
of smaller crystals was obtained from the mother liquor by
precipitation with pentane. Total yield of yellow-orange
crystalline complex 5 was 940 mg (76% based on Pd).
The crystals readily lose two THF crystallization molecules
upon drying. Anal. Calc. for C28H46O22Pd2Nd2: C, 27.21;
H, 3.75. Found: C, 27.41; H, 3.68%. IR spectrum
(KBr, cmꢀ1): 2977w, 2875w, 1622s (mas(CO)), 1577 vs
(mas(CO)), 1412vs (ms(CO)), 1344m, 1067w, 1050w, 1026m,
943 w, 875w, 690m, 674m, 621w, 529w, 460w.
2.4. PdNi(l-OOCMe)4 (NCMe) · 3MeCN (2)
This complex was prepared according to the same proto-
col as complex 1a (see above) starting from Pd3(OCOMe)6
(448 mg, 2 mmol) and Ni(OOCMe)2 Æ 4H2O (495 mg,
2 mmol). The yield of the yellow-green crystals of complex
2 was 820 mg (93% based on Pd). The crystals readily lose
the MeCN crystallization molecules in air. Anal. Calc. for
C10H15O8NPdNi: C, 27.15; N, 3.17; H, 3.42. Found: C,
27.26; N, 3.21; H, 3.50%. IR spectrum (KBr, cmꢀ1):
2944m, 2882w, 2317w, 2291w, 2256w, 1611s (mas(CO)),
1387s, br. (ms(CO)), 1342m, 1049w, 1025w, 700m, 628w.
UV–Vis spectrum (acetic acid): 325 nm (e = 1.9 · 103
l molꢀ1 cmꢀ1), 250 (e = 3.0 · 103 l molꢀ1 cmꢀ1).
2.8. Pd2Eu2(l-OOCMe)8(l,g2-OOCMe)2(THF)2 · THF
(6)
The complex was synthesized according to the same pro-
tocol starting from Pd3(OOCMe)6 (448 mg, 2 mmol) and
Eu(OOCMe)3 Æ 4H2O (800 mg, 2 mmol) followed by crys-
tallization from THF in a yield of 0.55 g. An additional
portion of smaller crystals was obtained from the mother
liquor by precipitation with pentane. Total yield of yel-
low-orange crystalline complex 6 was 1.05 g (79% based
on Pd). The crystals readily lose the THF crystallization
molecule upon drying. Anal. Calc. for C28H46O22Pd2Eu2:
C, 26.87; H, 3.71. Found: C, 26.93; H, 3.85%. IR spectrum
(KBr, cmꢀ1): 2926w, 2851w, 1634m (mas(CO)), 1580vs
(mas(CO)), 1413vs (ms(CO)), 1343w, 1029m, 943w, 877w,
689m, 676m, 620w, 470w, 357w.
2.5. PdMn(l-OOCMe)4(OH2) · THF (3)
The orange dry solid prepared according to the general
procedure from Pd3(OOCMe)6 (448 mg, 2 mmol) and
Mn(OOCMe)2 Æ 4H2O (490 mg, 2 mmol) was dissolved in
warm THF (5 ml) and stored at room temperature for
24 h. Orange crystals of the title complex (530 mg) were
separated by decantation, washed with cold THF and dried
at room temperature in an argon flow. An additional por-
tion of smaller crystals was obtained from the mother
liquor by precipitation with pentane. Total yield of com-
plex 3 was 875 mg (90% based on Pd). Anal. Calc. for
C12H22O10PdMn: C, 29.57; H, 4.55. Found: C, 28.96; H,
4.59%. IR spectrum (KBr, cmꢀ1): 3416m, 2987w, 2878w,
1605vs (mas(CO)), 1563vs (mas(CO)), 1422s, br. (ms(CO)),
1339m, 1154w, 1024w, 695m, 658w, 624w. UV–Vis spec-
trum (acetic acid): 340 nm (e = 1.0 · 103 l molꢀ1 cmꢀ1),
250 (e = 2.0 · 103 l molꢀ1 cmꢀ1).
2.9. Pd II Ce2 ðl; g2-OOCMeÞ ðg1-OOCMeÞ ðl-OOCMeÞ -
IV
ðH2OÞ 2ꢃ 2H2O ꢃ 2MeCOOH ꢃ C6H6 (7)
2
2
8
2
The crystals of complex 7 were obtained directly from the
reaction solution, omitting the evaporation and recrystalli-
zation stages.
A slurry of Pd3(OOCMe)6 (200 mg,
0.89 mmol) and Ce(OOCMe)3 Æ 4H2O (350 mg, 0.89 mmol)
in acetic acid (5 ml) was stirred at 90 ꢁC until the initial com-
plexes completely dissolved (1 h). Benzene (0.5 ml) was
added to a warm yellow solution that formed and the solu-
tion was slowly cooled in a water bath to room temperature.
The crystals of the title complex were separated by decanta-
tion and dried in air. The yield of yellow-orange crystalline
complex 7 was 520 mg (79% based on Pd). Anal. Calc. for
C34H58O32Pd2Ce2: C, 27.74; H, 3.97. Found: C, 27.69; H,
3.95%. IR spectrum (KBr, cmꢀ1): 3424vs, 2926w, 2854w,
2.6. PdZn(l-OOCMe)4(OH2) · THF (4)
The dry residue obtained according to the general proce-
dure from Pd3(OOCMe)6 (448 mg, 2 mmol) and Zn(OOC-
Me)2 Æ 2H2O (440 mg, 2 mmol) was crystallized from THF

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2075
1718w, 1559vs, br (mas(CO)), 1445vs, br (m(CO)), 1343w,
1272m, 1052w, 1020m, 934w, 669s, 616m, 469w.
the Pd and Cu atoms in the general and special positions
are 0.7, 0.3 and 0.3, 0.2, correspondingly. The refinement
procedure of the disordered heavy metal atoms includes
the alternative refinement of occupancies with restraints
on the equalized thermal motion parameters and conse-
quent refinement of the thermal motion parameters with
restrictions applied to occupancies. Such a refinement
resulted in a considerable decrease in the residual electron
density peaks and discrepancy factors. It should be noted
that in all the above-mentioned disordered structures the
refinement for lower symmetry space group did not elimi-
nated the disorder and only lead to high correlations
between the refined parameters. All the data reduction
and further calculations were performed using SAINT [27]
and SHELXTL-97 [28] program packages.
2.10. Pd2Cu(l-OOCMe)6 · 2C6H6 (8)
Palladium acetate Pd3(OOCMe)6 (448 mg, 2 mmol
based on Pd) and Cu(OOCMe)2 Æ H2O (199 mg, 1 mmol)
were stirred under reflux in glacial acetic acid (20 ml) until
the initial salts completely dissolved (ꢂ1.5 h). The reaction
solution was cooled to room temperature, filtered, concen-
trated on a rotary evaporator to 5 ml and stored for a night
at room temperature. The fine-crystalline precipitate was
filtered off (note: the precipitate should not be dry but
slightly wet with acetic acid!) and immediately recrystal-
lized from hot benzene to produce yellow-green crystals
of the title complex. An additional amount of smaller crys-
tals was obtained from the mother liquor by precipitation
with hexane. Total yield of the crystalline complex 8 was
473 mg (75 % based on Pd). The complex is soluble in
C6H6, AcOH, THF, and CH3CN (in two latter solvents
decomposes in several days). Anal. Calc. for
C12H18O12Pd2Cu: C, 22.85; H, 2.88. Found: C, 23.03; H,
3.01%. (crystals readily lose crystallization benzene mole-
cules upon drying). IR spectrum (KBr, cmꢀ1): 2988w,
2454w, 1607vs, br (mas(CO)), 1429vs (ms(CO)), 1348w,
1157w, 1029w, 948w, 695m, 625w, 580w. UV–Vis spectrum
(acetic acid):1 380 nm (e = 0.68 · 103 l molꢀ1 cmꢀ1), 260
(e = 1.5 · 103 l molꢀ1 cmꢀ1).
3. Results and discussion
3.1. Syntheses
Our experiments showed that Pd3(OOCMe)6 readily
reacts in an AcOH solution with the mononuclear manga-
nese(II), cobalt(II), nickel(II), copper(II), zinc(II), neodi-
mium(III), europium(III) and cerium(III) acetates to
form the mixed-metal complexes. Glacial acetic acid was
found to be the most convenient reaction medium. In other
solvents, such as benzene or THF, no PdII–MII,III reaction
was found to occur, whereas methanol and higher alcohols
were improper because of their reducing ability towards
palladium(II).
2.11. Data collection
Typically, the complex formation occurs to completion
for 1–2 h at 90–110 ꢁC. In all cases, except for Cu(OOC-
Me)2 Æ H2O, the reaction started from the PdII:MII,III molar
ratio 1:1 produced quite uniform samples of 1:1 heterome-
tallic complexes. Unlike this, the product composition of
the copper(II)–palladium(II) reaction depended on the ini-
tial PdII:CuII ratio, affording mixtures of differently colored
small crystals in most cases. Synthetic runs with various
CuII:PdII ratios showed that a chemically uniform sample
can be obtained in a good yield at the initial CuII:PdII ratio
equal to 1:2.
However, the prepared mixed-metal complex samples
were as a rule amorphous or microcrystalline and unsuit-
able for X-ray diffraction investigation. Only complexes 7
and 8 were precipitated directly from the reaction solution
as appropriate single crystals. For this reason, the mixed-
metal acetate complexes were treated with THF or MeCN
to furnish the complementary metal with a suitable addi-
tional ligand. All the synthesized PdII–MII,III heterometal-
lic complexes were obtained as well-shaped single crystals
and their structures were established by X-ray diffraction.
Details of the data collection and structure refinement
for complexes 1–8 are presented in Table 1. Single-crystal
X-ray diffraction experiments for complexes 1–6 and 8 were
carried out on a Bruker SMART 1000 with CCD area
detector (graphite monochromated Mo Ka radiation,
˚
k = 0.71073 A, x-scans) and that for complex 7 was per-
formed on an Enraf Nonius CAD 4 diffractometer (graph-
˚
ite monochromator, Mo Ka radiation, k = 0.71073 A, x-
scans). The semi-empirical method SADABS [26] was applied
for the absorption correction for crystals 1–6 and 8. The
structures were solved by direct methods and refined by
the full-matrix least-squares technique against F2 with the
anisotropic displacement parameters for all non-hydrogen
atoms. The hydrogen atoms of the water molecules in com-
plexes 3 and 4 were localized from Fourier syntheses; the
other hydrogen atoms in all structures were placed geomet-
rically and included in the structure factors calculation in
the riding motion approximation. Analysis of the Fourier
electron density synthesis in complexes 1a and 2 revealed
that the metal atoms are disordered over two positions with
equal occupancies. The distances between two positions in
˚
structures 1a and 2 are approximately 0.4 A. In complex 8
3.2. Structure of complexes
the Pd and Cu atoms are disordered over the coordination
triangle and their positions coincide. The occupancies of
The X-ray study revealed all the synthesized complexes
to contain the square-planar moiety [Pd(l-OOCMe)4] as
a structure-determining building block. The palladium
1
Spectrum recorded for fresh-prepared solution.

Table 1
Crystal data and structure refinement for complexes 1–8
1a
1b
2
3
4
5
6
7
8
Empirical formula
Fw
C
16H24N4O8PdCo
C11H16.5N1.5O8PdCo
463.09
C16H24N4O8PdNi
565.50
C12H22O10PdMn
487.64
C12H22O10PdZn
498.07
C36H62O24Pd2Nd2
1380.14
C36H62O24Pd2Eu2
1395.58
C34H58Ce2O32Pd2
1471.84
C24H30O12Pd2Cu
786.82
565.72
Colour
dark-cherry
200(2)
dark-cherry
160(2)
yellow-green
200(2)
orange
pink
yellow-orange
160(2)
yellow-orange
160(2)
yellow
yellow-green
160(2)
Temperature (K)
Crystal system
Space group
Unit cell dimensions
160(2)
160(2)
293(2)
orthorhombic
Pnma
monoclinic
P2(1)/c
monoclinic
P2(1)/n
triclinic
triclinic
monoclinic
P2(1)/c
orthorombic
Pca2(1)
triclinic
orthorombic
Pnma
ꢀ
ꢀ
ꢀ
P1
P1
P1
˚
a (A)
13.602(2)
16.786(3)
10.3033(17)
90
13.8704(16)
14.0563(17)
18.360(2)
90
10.735(2)
10.281(2)
10.979(3)
90
8.2095(16)
10.191(2)
11.630(2)
82.53
8.1673(14)
10.1232(17)
11.5326(19)
81.490
28.208(6)
13.376(3)
21.246(5)
90
21.114(4)
3.361(2)
34.950(6)
90
8.4420(17)
11.800(2)
14.133(3)
76.68
15.512(5)
23.043(7)
8.238 (2)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
108.232
90
102.067(4)
90
72.97
72.985
110.531
90
90
75.69
90
90
75.05
73.898
90
88.36
90
3
˚
V (A )
2352.4(7)
4 (0.5)
1.597
3399.8(7)
8 (2)
1184.9(5)
2 (0.5)
1.585
897.2(3)
2 (1)
873.7(3)
2 (1)
7507(3)
6 (1.5)
1.832
9860(3)
8 (4)
1326.9(5)
2(1)
2944.6(15)
4 (0.5)
1.775
Z (Z0)
Dcalc (Mg/m3)
Absorption coefficient
1.809
1.805
1.893
1.880
3.307
1.842
1.515
2.070
1.598
1.751
2.449
2.825
2.441
1.981 2
(mmꢀ1
F(000)
)
1140
1840
572
490
500
4092
5504
726
1564
Crystal size (mm)
h Range for data
collection (ꢁ)
0.36 · 0.32 · 0.39
2.43–29.98
0.34 · 0.32 · 0.24
1.86–27.00
0.29 · 0.24 · 0.23
2.41–30.02
0.34 · 0.30 · 0.28
1.83–30.01
0.25 · 0.15 · 0.10
1.85–29.97
0.32 · 0.27 · 0.24
1.83–30.04
0.34 · 0.28 · 0.22
1.80–30.05
0.26 · 0.22 · 0.20
2.06–25.08.
0.14 · 0.10 · 0.08
2.63–25.99
Index ranges
ꢀ19 6 h 6 19,
ꢀ20 6 k 6 23,
ꢀ11 6 l 6 14
17087
ꢀ16 6 h 6 17,
ꢀ17 6 k 6 17,
ꢀ17 6 l 6 23
21307
ꢀ15 6 h 6 15,
ꢀ14 6 k 6 14,
ꢀ15 6 l 6 15
12887
ꢀ11 6 h 6 10,
ꢀ14 6 k 6 10,
ꢀ16 6 l 6 15
8717
ꢀ11 6 h 6 11,
ꢀ14 6 k 6 14,
ꢀ16 6 l 6 16
10284
ꢀ39 6 h 6 20,
ꢀ12 6 k 6 18,
ꢀ29 6 l 6 29
56781
ꢀ27 6 h 6 29,
ꢀ18 6 k 6 18
ꢀ49 6 l 6 46
104423
ꢀ1 6 h 6 10,
ꢀ14 6 k 6 14
ꢀ16 6 l 6 16
5419
ꢀ19 6 h 6 19,
ꢀ28 6 k 6 28
ꢀ10 6 l 6 10
24350
Reflections collected
Independent reflections
3451 [0.0380]
7139 [0.0317]
3355 [0.0503]
5148 [0.0197]
4995 [0.0244]
21401 [0.0686]
28 183 [0.0720]
4668 [0.0117]
2919 [0.2042]
[Rint
]
Observed reflections
Data/restraints/
parameters
2155
5270
2285
4331
3797
10560
17253
4078
1345
3451/0/162
7139/0/406
3355/0/145
5148/0/217
4995/0/217
21 401/16/876
28 183/29/1152
4668/0/336
2919/0/172
Goodness-of-fit on F2
Final R indices
[I > 2r(I)]a
0.951
1.084
0.996
1.011
1.021
1.081
1.094
1.063
0.884
R1 = 0.0535,
wR2 = 0.1336
R1 = 0.0845,
wR2 = 0.1514
2.028 and ꢀ0.678
R1 = 0.0569,
wR2 = 0.1370
R1 = 0.0735,
wR2 = 0.1463
2.727 and ꢀ1.336
R1 = 0.0610,
wR2 = 0.1708
R1 = 0.0850,
wR2 = 0.1824
1.658 and ꢀ0.642
R1 = 0.0448,
wR2 = 0.1136
R1 = 0.0534,
wR2 = 0.1198
2.245 and ꢀ0.950
R1 = 0.0450,
wR2 = 0.1101
R1 = 0.0594,
wR2 = 0.1174
2.745 and ꢀ0.761
R1 = 0.0646,
wR2 = 0.1330
R1 = 0.1310,
wR2 = 0.1459
2.818 and ꢀ1.135
R1 = 0.0579,
wR2 = 0.1156
R1 = 0.1024,
wR2 = 0.1261
3.028 and ꢀ1.056
R1 = 0.0335,
wR2 = 0.0870
R1 = 0.0418,
wR2 = 0.0919
1.932 and ꢀ2.057
R1 = 0.0551,
wR2 = 0.1133
R1 = 0.1418,
wR2 = 0.1435
1.080 and ꢀ0.665
Ra indices (all data)
Largest difference in
peak and hole (e Aꢀ3
b
)
P
P
P
P
2
2 1=2
a
R1
¼
jjF oj ꢀ jF cjj= jF oj; wR2 ¼ f ½wðF 2o ꢀ F c2Þ ꢁ= wðF o2 Þ g
.
b
In all structures the largest difference peak is observed in the vicinity of heavy atom.

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2077
atom in all the complexes is linked to the complementary
metal atom through carboxylate bridges, forming the fol-
lowing geometrical figures:
(iii) double-bridged triangle of two Pd atoms and one Cu
atom almost identical to the Pd3(OOCMe)6 triangle.
Me
Me
C
O
C
(i) four-bridged asymmetrical ‘‘chinese lanthern’’ with an
axial ligand attached to the complementary metal atom
O
O
O
M
M
O
O
Me
O
O
Me
C
C
C
Me
Me
O
M
O
O
O
C
C
C
O
O
O
O
O
Me
Me
Pd
L
M
M = Pd, Cu
O
O
C
O
Me
C
The structural motif of the first two geometries is ‘‘face-
to face’’ arrangement of the PdII and MII,III coordination
planes, whereas in the third geometry the PdII and CuII
coordination planes are turned 60ꢁ to each other.
Me
M = Co, Ni; L = MeCN
(ii) two four-bridged ‘‘chinese lanthers’’ linked to each
other by two acetate or two hydrogen-bonded ace-
tate bridges attached to the M atoms
Type 1: binuclear ‘‘chinese lanthern’’ complexes. PdCo(l-
OOCMe)4(NCMe) · 3MeCN (1a) [29], PdCo(l-
Me
Me
OOCMe)4(NCMe) · 0.5MeCN
(1b),
and
Me
Me
PdNi(l-OOCMe)4(NCMe) · 3MeCN (2). The
molecular structures of the Pd–Co and Pd–Ni
acetates are quite similar (see Figs. 1–3).
C
C
O
O
O
O
C
C
O
O
O
O
O
O
Pd
Pd
M
M
Meanwhile, the crystal structures of these com-
plexes have some peculiarities. In the crystal of
complex 1a, one of three MeCN crystallization
molecules is positioned rather close to the
complex molecule, forming a fairly short Pdꢄ ꢄ ꢄN
contact between the Pd atom and MeCN
O
O
O
O
C
C
Me
O
O
MeC
Me
M = Nd, Eu, Ce: ∩ = OOCMe; M = Mn, Zn: ∩ = OC(Me)O–H···O
C
Me
Fig. 1. Molecular structure of the complex PdCo(l-OOCMe)4(NCMe) · 3 MeCN (1a) with thermal ellipsoids drawn at 50% probability level. The Pd and
Co atoms are disordered over two positions with equal occupancies (two MeCN crystallization molecules are not shown).

2078
N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
Fig. 2. Molecular structure of the complex PdCo(l-OOCMe)4(NCMe) · 0.5 MeCN (1b) with thermal ellipsoids drawn at 50% probability level.
Fig. 3. Molecular structure of the complex PdNi(l-OOCMe)4(NCMe) · 3 MeCN (2) with thermal ellipsoids drawn at 50% probability level. The Pd and
Ni atoms are disordered over two positions with equal occupancies (two MeCN crystallization molecules are not shown).
˚
crystallization molecule (Pd(1)–N(1) 2.509 A,
Fig. 1). Crystal 1b (Fig. 2) contains two slightly
different molecules PdCo(l-OOCMe)4(NCMe),
one of which (A) has no short contacts, while
another molecule (B) is drawn together with the
MeCN crystallization molecule. It can be seen
from Tables 2 and 3 that the Pdꢄ ꢄ ꢄN contact in
molecules 1a and 1b(B) somewhat changes their
geometry compared to that of molecule 1b(A),
slightly shortening the Pd–Co distance
˚
(Pd(1)–Co(2) 2.515(3) A in 1a, Pd(2)–Co(2)
˚
2.4591(10) A in 1b(B)) and elongating the Co–N

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2079
Table 2
Selected bond lengths (A) and angles (ꢁ) for complex 1a
Table 4
Selected bond lengths (A) and angles (ꢁ) in complex 2
˚
˚
Pd(1)–Co(2)
Pd(1)–O(1)
Pd(1)–O(3)
Co(2)–O(2)
Co(2)–O(4)
Co(2)–N(2)
Pd(1). . .N(1)
2.515(3)
2.025(3)
2.041(3)
2.070(4)
2.027(4)
2.279(6)
2.509(5)
Pd(2)–Co(1)
Pd(2)–O(2)
Pd(2)–O(4)
Co(1)–O(1)
Co(1)–O(3)
Co(1)–N(1)
Pd(2). . .N(2)
2.551(3)
2.013(3)
2.037(3)
2.091(4)
2.050(4)
2.073(5)
2.678(6)
Pd(1)–Ni(1)
Pd(1)–O(2)
Pd(1)–O(4)
Ni(1)–O(2A)a
Ni(1)–O(4)a
Pd(1). . .N(1)
2.483(2)
2.034(5)
2.020(5)
2.055(6)
2.040(6)
2.526(6)
Pd(1)–O(1)
Pd(1)–O(3)
Ni(1)–O(1A)a
Ni(1)–O(3A)a
Ni(1)–N(1A)a
2.027(4)
2.036(4)
2.076(6)
2.028(6)
2.160(6)
O(1)–Pd(1)–O(2)
O(4)–Pd(1)–O(1)
O(1A)a–Ni(1)–Pd(1)
O(3A)a–Ni(1)–Pd(1)
Ni(1)–Pd(1)–N(1)
a
Symmetry transformations used to generate equivalent atoms:
ꢀx, ꢀy, ꢀz.
90.82(18)
89.53(19)
80.83(12)
82.34(13)
178.87(11)
O(2)–Pd(1)–O(3)
88.85(18)
90.56(18)
82.31(12)
81.03(12)
O(1)–Pd(1)–O(3)
O(1A)a–Pd(1)–O(1)
O(3)–Pd(1)–O(3A)a
O(1)–Pd(1)–Co(2)
O(3)–Pd(1)–Co(2)
N(2)–Co(2)–Pd(1)
a
90.69(9)
89.78(15)
88.74(14)
91.18(11)
91.27(12)
176.7(3)
O(2)–Pd(2)–O(4)
O(2A)a–Pd(2)–O(2)
O(4)–Pd(2)–O(4A)a
O(2)–Pd(2)–Co(1)
O(4)–Pd(2)–Co(1)
N(1)–Co(1)–Pd(2)
90.67(9)
89.58(16)
88.72(16)
93.56(11)
90.97(11)
177.1(3)
O(4)–Pd(1)–O(3)
O(2A)a–Ni(1)–Pd(1)
O(4A)a–Ni(1)–Pd(1)
Symmetry transformations used to generate equivalent atoms:
x, ꢀy + 3/2, z.
metal would be an octahedron. Alternatively, if
the direct Pd–Co(Ni) bond were lacking, the
MO5 coordination polyhedron of the complemen-
tary metals would be a tetragonal pyramide. A
similar problem arises when discussing the other
PdII-based complexes under study. Studies of
the magnetic properties and quantum chemistry
of these complexes, which are in progress now,
could clarify the problem.
Table 3
Selected geometrical parameters for two independent molecules (A and B)
in crystal 1b
Molecule A
Molecule B
˚
Bond lengths (A)
Pd(1)–Co(1)
Pd(1)–O(1)
Pd(1)–O(3)
Pd(1)–O(5)
Pd(1)–O(7)
Co(1)–O(2)
Co(1)–O(4)
Co(1)–O(6)
Co(1)–O(8)
Co(1)–N(1)
2.5304(8)
2.000(4)
2.006(4)
1.994(4)
1.996(4)
2.082(4)
2.061(4)
2.085(4)
2.037(4)
2.057(5)
Pd(2)–Co(2)
Pd(2)–O(9)
2.4591(10)
2.008(4)
2.017(4)
2.000(4)
2.012(4)
2.069(4)
2.054(4)
2.056(4)
2.047(4)
2.183(6)
2.687(6)
Pd(2)–O(11)
Pd(2)–O(13)
Pd(2)–O(15)
Co(2)–O(10)
Co(2)–O(12)
Co(2)–O(14)
Co(2)–O(16)
Co(2)–N(2)
Pd(2). . .N(3)
Type 2: two ‘‘chinese lantherns’’ linked to each other.
PdMn(l-OOCMe)4(OH2) · THF
(3)
and
PdZn(l-OOCMe)4(OH2) · THF (4). The palla-
dium – complementary metal units of these com-
plexes are similar to those of complexes 1a,b and
2 with the exception that the additional ligand
L = H2O instead of L = MeCN is connected to
the complementary metals (Figs. 4 and 5, Tables
5 and 6).2
Bond angles (ꢁ)
O(1)–Pd(1)–O(3)
O(5)–Pd(1)–O(3)
O(5)–Pd(1)–O(7)
O(7)–Pd(1)–O(1)
O(1)–Pd(1)–Co(1)
O(3)–Pd(1)–Co(1)
O(5)–Pd(1)–Co(1)
O(7)–Pd(1)–Co(1)
N(1)–Co(1)–Pd(1)
88.97(16)
90.33(16)
89.43(17)
91.29(17)
90.96(10)
89.77(11)
90.24(11)
89.26(11)
177.39(14)
O(9)–Pd(2)–O(15)
O(13)–Pd(2)–O(9)
O(13)–Pd(2)–O(11)
O(15)–Pd(2)–O(11)
O(9)–Pd(2)–Co(2)
O(11)–Pd(2)–Co(2)
O(13)–Pd(2)–Co(2)
O(15)–Pd(2)–Co(2)
N(2)–Co(2)–Pd(2)
90.29(16)
88.46(17)
91.64(17)
89.59(15)
89.26(12)
89.79(11)
90.40(12)
88.62(11)
174.67(14)
Meanwhile, the molecules 3 and 4 are packed in
the crystals in another way: the Pd–Mn and Pd–
Zn binuclear moieties are connected by two H-
bonded bridges
Me
H
O
C
O
H O
Mn(Zn)
Mn(Zn)
˚
˚
bond (Co(2)–N(2) 2.279(6) A in 1a, Co(2)–N(2)
(H(2w)–O(6A) 1.86 and 1.78 A; O(6)ꢄ ꢄ ꢄO(9)
˚
˚
2.183(6) A
in
1b(B))
(cf.
Pd(1)–Co(1)
2.691(6) and 2.692(6) A in complexes 3 and 4,
˚
˚
2.5304(8) A, Co(1)–N(1) 2.057(5) A in 1b(A)).
Similar short contacts Pd–N are observed in the
Pd–Ni crystal 2 Pd(1)–Ni(1) 2.526(6) A (Fig. 3,
respectively, see Fig. 6). Such a contact results
in a noticeable elongation of one the M–O dis-
tance compared to the other ones (M–O(6)
˚
˚
Table 4).
2.200(3) and 2.135(3) A for complexes 3 and 4,
The metal–metal distances in molecules 1a, 1b,
and 2 are much shorter than the sum of van der
Waals radii of the corresponding metals, being
rather close to the sum of the metal covalent radii
respectively, see Tables 5 and 6). Hence, com-
pounds 3 and 4 can be classified, at least in the
crystal phase, as tetranuclear di-chinese lanthern
complexes. In addition, the coordinated H2O
molecules are H-bonded to the THF crystallization
˚
(cf. Pd–Co 2.44, Pd–Ni 2.43 A). Meanwhile, the
direct metal–metal bonding between PdII (4d8)
and CoII (3d5) or NiII (3d8) seems to be question-
able. If the PdII–MII bonding were taken into
account, the coordination polyhedron of the 3d-
2
The H2O molecules in the composition of complexes 3 and 4 are
originated from the initial Mn(OOCMe)2 Æ 4H2O and Zn(OOC-
Me)2 Æ 2H2O reagents and/or residual water in solvents.

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N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
Table 5
Selected bond lengths (A) and angles (ꢁ) in complex 3
˚
Pd(1)–Mn(1)
Pd(1)–O(3)
Pd(1)–O(7)
Mn(1)–O(4)
Mn(1)–O(8)
2.6795(10)
2.000(3)
2.001(3)
2.141(3)
2.127(3)
Pd(1)–O(1)
Pd(1)–O(5)
Mn(1)–O(2)
Mn(1)–O(6)
Mn(1)–O(9)
2.002(3)
2.004(3)
2.139(3)
2.200(3)
2.070(3)
O(1)–Pd(1)–O(5)
O(7)–Pd(1)–O(3)
O(1)–Pd(1)–Mn(1)
O(5)–Pd(1)–Mn(1)
O(2)–Mn(1)–Pd(1)
O(8)–Mn(1)–Pd(1)
O(9)–Mn(1)–Pd(1)
89.91(11)
89.90(11)
90.79(8)
91.60(8)
77.52(7)
78.25(8)
174.58(9)
O(3)–Pd(1)–O(1)
O(7)–Pd(1)–O(5)
O(3)–Pd(1)–Mn(1)
O(7)–Pd(1)–Mn(1)
O(4)–Mn(1)–Pd(1)
O(6)–Mn(1)–Pd(1)
90.25(11)
89.93(11)
90.46(8)
89.77(8)
77.77(8)
76.81(7)
Table 6
˚
Selected bond lengths (A) and angles (ꢁ) in complex 4
Pd(1)–Zn(1)
Pd(1)–O(1)
Pd(1)–O(3)
Pd(1)–O(5)
Pd(1)–O(7)
2.5811(6)
2.003(3)
1.998(3)
1.998(3)
1.999(3)
Zn(1)–O(2)
Zn(1)–O(4)
Zn(1)–O(6)
Zn(1)–O(8)
Zn(1)–O(9)
2.049(3)
2.068(3)
2.135(3)
2.064(2)
1.968(3)
O(3)–Pd(1)–O(7)
O(5)–Pd(1)–O(1)
O(1)–Pd(1)–Zn(1)
O(3)–Pd(1)–Zn(1)
O(5)–Pd(1)–Zn(1)
O(7)–Pd(1)–Zn(1)
O(9)–Zn(1)–Pd(1)
89.83(11)
89.94(11)
88.93(8)
89.52(7)
91.25(7)
90.56(7)
176.08(9)
O(7)–Pd(1)–O(5)
O(3)–Pd(1)–O(1)
O(2)–Zn(1)–Pd(1)
O(4)–Zn(1)–Pd(1)
O(6)–Zn(1)–Pd(1)
O(8)–Zn(1)–Pd(1)
90.02(11)
90.21(11)
81.72(8)
80.98(8)
79.65(7)
80.01(7)
Fig. 4. Molecular structure of the complex PdMn(l-OOCMe)4(OH2) (3)
with thermal ellipsoids drawn at 50% probability level.
˚
molecules (H(1w)ꢄ ꢄ ꢄO(10) 1.96 and 1.82 A; O(9)ꢄ ꢄ ꢄ
˚
O(10) 2.653(7) and 2.655(7) A in complexes 3 and
4, respectively).
Tetranuclear complexes Pd2Nd2(l-OOCMe)8
(l,g2-OOCMe)2(THF)2 · 2THF (5), Pd2Eu2(l-
OOCMe)8(l,g2-OOCMe)2(THF)2 · THF
(6)
and Pd2IICe2 ðl; g2-OOCMeÞ2ðg1-OOCMeÞ2ðl-
OOCMeÞ8ðH2OÞ2ð7Þ are built of two Pd–
Nd(Eu,Ce) ‘‘chinese lanthern’’ binuclear units
connected by two l,g2-acetate bridges (Ndꢄ ꢄ ꢄNd
IV
˚
4.1442(8) and 4.1691(8) A; Nd–O 2.449(5)–
˚
˚
2.557(5) A; Euꢄ ꢄ ꢄEu 4.0822(9) and 4.0962(9) A,
˚
Eu–O 2.404(7)–2.525(7) A; Ceꢄ ꢄ ꢄCe 4.4691(8),
˚
Ce–O 2.432(3)–2.527(3) A) (Figs. 7–9 and Tables
7–9).
In each of the ‘‘chinese lanthern’’ fragment, simi-
larly to complexes 1 and 2, the Pd–Nd(Eu, Ce)
metal distances (Pd–Nd 3.2125(9)–3.2411(10),
˚
Pd–Ce
Pd–Eu
3.2026(10)–3.2170(10) A,
˚
3.4022(9) A) are much shorter than the sum of
the van der Waals radii of the corresponding met-
als, being close to the sum of the metal covalent
˚
radii (cf. Pd–Nd 2.92, Pd–Eu 3.11 A, Pd–Ce
˚
2.93 A). The coordination sphere of each Nd,
Eu atom is complemented with an O-bonded
THF molecule, thus gaining a coordination num-
ber of eight under assumption of lacking the
direct PdII–NdIII(EuIII) metal–metal bond.
Fig. 5. Molecular structure of the complex PdZn(l-OOCMe)4(OH2) (4)
with thermal ellipsoids drawn at 50% probability level.

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2081
Fig. 6. Structure of complexes 3 and 4 in the crystals (M = Mn, Zn).
Fig. 7. Molecular structure of the complex Pd2Nd2(l-OOCMe)8(l,g2-OOCMe)2(THF)2 Æ (5) with thermal ellipsoids drawn at 50% probability level.

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N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
Fig. 8. Molecular structure of the complex Pd2Eu2(l-OOCMe)8(l,g2-OOCMe)2(THF)2 Æ (6) with thermal ellipsoids drawn at 50% probability level.
IV
Fig. 9. Molecular structure of the complex Pd2IICe2 ðl; g2-OOCMeÞ2ðg1-OOCMeÞ2ðl-OOCMeÞ8ðH2OÞ2 ð7Þ with thermal ellipsoids drawn at 30%
probability level.

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2083
Table 7
Table 8
Selected geometrical parameters for two independent molecules in crystal
Selected geometrical parameters for two independent molecules in crystal
5
6
˚
Bond lengths (A)
Molecule A
Molecule B
Molecule A
˚
Bond lengths (A)
Eu(1)–Pd(1)
Eu(2)–Pd(2)
Eu(1)–Eu(2)
Pd(1)–O(1)
Pd(1)–O(3)
Pd(1)–O(5)
Pd(1)–O(7)
Pd(2)–O(9)
Pd(2)–O(11)
Pd(2)–O(13)
Pd(2)–O(15)
Eu(1)–O(2)
Eu(1)–O(4)
Eu(1)–O(6)
Eu(1)–O(8)
Eu(1)–O(17)
Eu(1)–O(18)
Eu(1)–O(19)
Eu(1)–O(41)
Eu(2)–O(10)
Eu(2)–O(12)
Eu(2)–O(14)
Eu(2)–O(16)
Eu(2)–O(17)
Eu(2)–O(19)
Eu(2)–O(20)
Eu(2)–O(42)
Nd(1)–Pd(1)
Nd(1). . .Nd(2)
Pd(1)–O(3)
3.2275(9)
4.1691(8)
2.004(6)
2.016(6)
2.011(6)
2.007(6)
2.394(6)
2.432(6)
2.557(5)
2.529(5)
2.397(6)
2.432(5)
2.512(5)
2.501(5)
Nd(2)–Pd(2)
Pd(1)–O(1)
Pd(1)–O(5)
Pd(2)–O(9)
Pd(2)–O(13)
Nd(1)–O(2)
Nd(1)–O(6)
Nd(1)–O(17)
Nd(1)–O(20)
Nd(2)–O(10)
Nd(2)–O(14)
Nd(2)–O(17)
Nd(2)–O(19)
3.2125(9)
2.002(6)
1.989(6)
2.016(6)
1.987(6)
2.425(6)
2.434(5)
2.449(5)
2.495(5)
2.421(5)
2.444(5)
2.561(5)
2.423(5)
3.2170(10) Eu(3)–Pd(3)
3.2026(10) Eu(4)–Pd(4)
3.2043(11)
3.2083(11)
4.0962(9)
1.976(8)
1.976(9)
2.012(8)
1.996(9)
2.019(8)
2.004(8)
2.002(8)
1.970(8)
2.374(8)
2.400(7)
2.362(8)
2.365(8)
2.382(7)
2.525(7)
2.480(7)
2.448(8)
2.366(8)
2.379(8)
2.387(8)
2.393(8)
2.497(7)
2.442(8)
2.420(7)
2.460(7)
4.0822(9)
1.999(7)
1.962(9)
2.015(8)
1.999(9)
1.996(8)
1.982(9)
1.978(10)
2.007(8)
2.354(7)
2.405(7)
2.364(8)
2.387(8)
2.509(8)
2.496(7)
2.404(7)
2.436(8)
2.332(9)
2.395(7)
2.421(7)
2.356(7)
2.399(7)
2.495(7)
2.469(8)
2.494(8)
Eu(3)–Eu(4)
Pd(3)–O(21)
Pd(3)–O(23)
Pd(3)–O(25)
Pd(3)–O(27)
Pd(4)–O(29)
Pd(4)–O(31)
Pd(4)–O(33)
Pd(4)–O(35)
Eu(3)–O(22)
Eu(3)–O(24)
Eu(3)–O(26)
Eu(3)–O(28)
Eu(3)–O(37)
Eu(3)–O(39)
Eu(3)–O(40)
Eu(3)–O(43)
Eu(4)–O(30)
Eu(4)–O(32)
Eu(4)–O(34)
Eu(4)–O(36)
Eu(4)–O(37)
Eu(4)–O(38)
Eu(4)–O(39)
Eu(4)–O(44)
Pd(1)–O(7)
Pd(2)–O(11)
Pd(2)–O(15)
Nd(1)–O(4)
Nd(1)–O(8)
Nd(1)–O(19)
Nd(1)–O(31)
Nd(2)–O(12)
Nd(2)–O(16)
Nd(2)–O(18)
Nd(2)–O(32)
Molecule B
Nd(3)–Pd(3)
Pd(3)–O(21)
Pd(3)–O(25)
Nd(3)–O(22)
Nd(3)–O(26)
Nd(3)–O(29)
Nd(3)–O(30A)a
Nd(3)–O(33)
3.2411(10) Nd(3). . .Nd(3A)a
4.1442(8)
2.013(6)
2.005(5)
2.401(6)
2.420(5)
2.547(5)
1.995(6)
1.970(6)
2.416(5)
2.440(5)
2.445(5)
2.520(5)
2.514(6)
Pd(3)–O(23)
Pd(3)–O(27)
Nd(3)–O(24)
Nd(3)–O(28)
Nd(3)–O(29A)a
Bond angles (ꢁ)
Molecule A
O(1)–Pd(1)–O(3)
O(3)–Pd(1)–O(7)
O(11)–Pd(2)–O(9)
O(13)–Pd(2)–O(9)
O(2)–Nd(1)–Pd(1)
O(6)–Nd(1)–Pd(1)
O(17)–Nd(1)–Pd(1) 132.35(12)
O(20)–Nd(1)–Pd(1) 117.30(13)
O(10)–Nd(2)–Pd(2)
O(14)–Nd(2)–Pd(2)
89.4(2)
90.4(2)
89.3(3)
89.0(3)
62.49(13)
63.53(13)
O(5)–Pd(1)–O(1)
O(5)–Pd(1)–O(7)
89.1(2)
90.9(2)
90.7(3)
90.8(3)
61.84(12)
63.72(13)
135.90(12)
130.93(14)
62.91(13)
63.05(12)
121.37(12)
128.83(13)
Bond angles (ꢁ)
O(13)–Pd(2)–O(15)
O(15)–Pd(2)–O(11)
O(4)–Nd(1)–Pd(1)
O(8)–Nd(1)–Pd(1)
O(19)–Nd(1)–Pd(1)
O(31)–Nd(1)–Pd(1)
O(12)–Nd(2)–Pd(2)
O(16)–Nd(2)–Pd(2)
O(18)–Nd(2)–Pd(2)
O(32)–Nd(2)–Pd(2)
O(1)–Pd(1)–O(5)
O(3)–Pd(1)–O(1)
O(3)–Pd(1)–O(7)
O(7)–Pd(1)–O(5)
O(11)–Pd(2)–O(9)
O(9)–Pd(2)–O(15)
O(13)–Pd(2)–O(11)
O(13)–Pd(2)–O(15)
O(2)–Eu(1)–Pd(1)
O(4)–Eu(1)–Pd(1)
O(6)–Eu(1)–Pd(1)
O(8)–Eu(1)–Pd(1)
90.2(3)
87.0(3)
91.6(4)
91.1(4)
90.8(4)
90.2(4)
87.6(4)
91.3(4)
64.20(1)
62.29(19)
62.6(2)
62.78(18)
O(21)–Pd(3)–O(25)
O(23)–Pd(3)–O(21)
O(23)–Pd(3)–O(27)
O(27)–Pd(3)–O(25)
O(31)–Pd(4)–O(29)
O(33)–Pd(4)–O(29)
O(35)–Pd(4)–O(33)
O(35)–Pd(4)–O(31)
O(22)–Eu(3)–Pd(3)
O(24)–Eu(3)–Pd(3)
O(26)–Eu(3)–Pd(3)
O(28)–Eu(3)–Pd(3)
89.7(4)
88.9(4)
92.0(4)
89.3(4)
89.0(3)
90.4(4)
91.7(3)
88.8(3)
64.2(2)
62.80(18)
62.76(19)
63.37(18)
64.14(14)
62.96(13)
O(17)–Nd(2)–Pd(2) 143.00(11)
O(19)–Nd(2)–Pd(2) 126.96(12)
Molecule B
O(21)–Pd(3)–O(23)
O(27)–Pd(3)–O(23)
O(22)–Nd(3)–Pd(3)
O(26)–Nd(3)–Pd(3)
O(29)–Nd(3)–Pd(3) 127.45(12)
O(33)–Nd(3)–Pd(3) 128.05(14)
90.5(2)
90.8(3)
62.92(13)
63.01(13)
O(25)–Pd(3)–O(21)
O(25)–Pd(3)–O(27)
O(24)–Nd(3)–Pd(3)
O(28)–Nd(3)–Pd(3)
O(29A)a-Nd(3)–Pd(3) 138.66(12)
O(30A)a-Nd(3)–Pd(3) 122.56(12)
87.1(3)
91.4(3)
62.19(13)
62.42(12)
O(17)–Eu(1)–Pd(1) 142.42(17)
O(18)–Eu(1)–Pd(1) 122.99(18)
O(19)–Eu(1)–Pd(1) 125.63(16)
O(41)–Eu(1)–Pd(1) 128.9(2)
O(37)–Eu(3)–Pd(3) 126.58(17)
O(39)–Eu(3)–Pd(3) 142.09(17)
O(40)–Eu(3)–Pd(3) 122.03(17)
O(43)–Eu(3)–Pd(3) 128.5(2)
O(22)–Eu(3)–Eu(4) 106.4(2)
O(24)–Eu(3)–Eu(4)
O(26)–Eu(3)–Eu(4) 149.50(19)
O(28)–Eu(3)–Eu(4) 115.31(19)
O(37)–Eu(3)–Eu(4)
O(39)–Eu(3)–Eu(4)
O(40)–Eu(3)–Eu(4)
O(43)–Eu(3)–Eu(4)
Pd(3)–Eu(3)–Eu(4)
O(30)–Eu(4)–Pd(4)
O(32)–Eu(4)–Pd(4)
O(34)–Eu(4)–Pd(4)
O(36)–Eu(4)–Pd(4)
O(2)–Eu(1)–Eu(2)
O(4)–Eu(1)–Eu(2)
O(6)–Eu(1)–Eu(2)
O(8)–Eu(1)–Eu(2)
O(17)–Eu(1)–Eu(2)
O(18)–Eu(1)–Eu(2)
O(19)–Eu(1)–Eu(2)
O(41)–Eu(1)–Eu(2)
Pd(1)–Eu(1)–Eu(2)
O(10)–Eu(2)–Pd(2)
O(12)–Eu(2)–Pd(2)
O(16)–Eu(2)–Pd(2)
O(14)–Eu(2)–Pd(2)
106.2(2)
84.24(19)
150.6(2)
115.62(19)
32.87(17)
79.56(18)
34.26(17)
78.5(2)
146.46(2)
62.3(2)
63.0(2)
63.94(18)
63.70(17)
84.72(18)
a
Symmetry transformations used to generate equivalent atoms: ꢀx + 1,
ꢀy + 2, ꢀz + 1.
33.79(17)
33.24(16)
79.68(17)
78.4(2)
147.47(3)
62.2(2)
62.7(2)
63.6(2)
63.82(19)
The Pd–Ce complex 7 differs from complexes 5
and 6 by chemical composition: unlike the Pd–
Nd and Pd–Eu complexes, it contains 12 rather
than 10 acetate groups per the Pd2Ce2 formula
unit. Hence, the cerium atoms in complex 7 are
in the oxidation state +4. This is due to the fact
that the starting cerium(III) salt is readily oxi-
dized with the air oxygen to cerium(IV) under
the synthesis conditions. The additional acetate
anions are connected to the cerium atoms by the
O(19)–Eu(2)–Pd(2) 136.69(16)
O(17)–Eu(2)–Pd(2) 129.89(18)
O(20)–Eu(2)–Pd(2) 119.56(18)
O(42)–Eu(2)–Pd(2) 130.0(2)
O(38)–Eu(4)–Pd(4) 117.69(19)
O(37)–Eu(4)–Pd(4) 136.84(16)
O(39)–Eu(4)–Pd(4) 131.31(18)
O(44)–Eu(4)–Pd(4) 129.7(2)
(continued on next page)

2084
N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
g1-mode (see Fig. 9), supplementing their coordi-
nation spheres to a normal coordination number
of nine.
Table 8 (continued)
Molecule A
Molecule B
Bond angles (ꢁ)
The X-ray diffraction study revealed that two of
14 acetate groups belong to the acetic acid mole-
cules of crystallization, whereas the other 12
MeCOO groups are connected to the metal atoms
as acido ligands.
O(10)–Eu(2)–Eu(1) 150.6(2)
O(12)–Eu(2)–Eu(1) 100.5(2)
O(30)–Eu(4)–Eu(3) 150.0(2)
O(32)–Eu(4)–Eu(3)
99.4(2)
O(14)–Eu(2)–Eu(1)
82.26(17)
O(34)–Eu(4)–Eu(3) 121.31(19)
O(16)–Eu(2)–Eu(1) 120.04(19)
O(36)–Eu(4)–Eu(3)
O(37)–Eu(4)–Eu(3)
O(38)–Eu(4)–Eu(3)
O(39)–Eu(4)–Eu(3)
O(44)–Eu(4)–Eu(3)
83.02(19)
32.04(16)
80.03(17)
34.90(17)
82.29(19)
O(17)–Eu(2)–Eu(1)
O(19)–Eu(2)–Eu(1)
O(20)–Eu(2)–Eu(1)
O(42)–Eu(2)–Eu(1)
34.58(19)
32.85(16)
79.48(18)
81.8(2)
Type 3: double-bridged Pd2–Cu triangle. Triangle complex
Pd2Cu(l-OOCMe)6 (8). As mentioned above (see
Section 2), the reaction between PdII and CuII
acetates is noticeably different from the other het-
erometallic systems. The reaction between palla-
dium(II) and copper(II) acetates seems to
produce several different complexes depending
on the reactants ratio. It was found in earlier
work [20,21] that heating of the equimolar
amounts of PdII and CuII acetates in acetic acid
afforded a mixture of PdII–CuII acetates with dif-
ferent compositions, including CuPd(OAc)4 and
CuPd2(OAc)6. We also were not able to prepare
the pure 1:1 complex CuPd(OAc)4 when reacted
Pd3(OAc)6 with Cu(OAc)2. Instead, small crystals
of the yellow-green (palladium–copper) and green
(purely copper) acetates were seen with an optical
microscope in the reaction product. The best
preparations were made when using the 2:1 initial
Pd:Cu ratio followed by crystallization from ben-
zene to afford adoptable for X-ray diffraction
analysis yellow-green crystals of the complex
Pd2Cu(l-OOMe)6 (8).
Pd(2)–Eu(2)–Eu(1) 144.81(2)
Pd(4)–Eu(4)–Eu(3) 145.21(2)
Table 9
Selected bond lengths (A) and angles (ꢁ) in complex 7
˚
Ce(1)–O(8)
Ce(1)–O(6)
Ce(1)–O(4)
Ce(1)–O(13)
Ce(1)–O(9)
Ce(1)–Pd(1)
Pd(1)–O(3)
Pd(1)–O(5)
2.432(3)
2.527(3)
2.546(3)
2.576(4)
2.670(3)
3.4022(9) Pd(1)–O(1)
1.985(3)
2.001(3)
Ce(1)–O(2)
Ce(1)–O(9)#1
Ce(1)–O(12)
Ce(1)–O(10)
Ce(1)–C(9)
2.478(3)
2.541(3)
2.552(3)
2.590(3)
3.021(4)
1.990(3)
1.986(3)
2.541(3)
Pd(1)–O(7)
O(9)–Ce(1)#1
O(8)–Ce(1)–O(2)
O(2)–Ce(1)–O(6)
O(2)–Ce(1)–O(9)#1
O(8)–Ce(1)–O(4)
O(6)–Ce(1)–O(4)
O(8)–Ce(1)–O(12)
O(6)–Ce(1)–O(12)
O(4)–Ce(1)–O(12)
O(2)–Ce(1)–O(13)
O(9)#1–Ce(1)–O(13)
O(12)–Ce(1)–O(13)
O(2)–Ce(1)–O(10)
117.78(11)
71.05(11)
144.79(10)
76.58(11)
119.29(10)
142.29(11)
136.17(11)
69.68(11)
133.73(11)
81.26(10)
136.61(12)
79.05(10)
O(8)–Ce(1)–O(6)
O(8)–Ce(1)–O(9)#1
O(6)–Ce(1)–O(9)#1
O(2)–Ce(1)–O(4)
O(9)#1–Ce(1)–O(4)
O(2)–Ce(1)–O(12)
O(9)#1–Ce(1)–O(12)
O(8)–Ce(1)–O(13)
O(6)–Ce(1)–O(13)
O(4)–Ce(1)–O(13)
O(8)–Ce(1)–O(10)
O(6)–Ce(1)–O(10)
O(4)–Ce(1)–O(10)
O(13)–Ce(1)–O(10)
O(2)–Ce(1)–O(9)
O(9)#1–Ce(1)–O(9)
O(12)–Ce(1)–O(9)
O(10)–Ce(1)–O(9)
O(2)–Ce(1)–C(9)
O(9)#1–Ce(1)–C(9)
O(12)–Ce(1)–C(9)
O(10)–Ce(1)–C(9)
O(8)–Ce(1)–Pd(1)
O(6)–Ce(1)–Pd(1)
O(4)–Ce(1)–Pd(1)
O(13)–Ce(1)–Pd(1)
O(9)–Ce(1)–Pd(1)
O(7)–Pd(1)–O(3)
O(3)–Pd(1)–O(1)
O(3)–Pd(1)–O(5)
O(7)–Pd(1)–Ce(1)
O(1)–Pd(1)–Ce(1)
C(1)–O(1)–Pd(1)
C(3)–O(3)–Pd(1)
C(5)–O(5)–Pd(1)
C(7)–O(7)–Pd(1)
C(9)–O(9)–Ce(1)#1
Ce(1)#1–O(9)–Ce(1)
C(11)–O(12)–Ce(1)
O(9)–C(9)–Ce(1)
75.59(10)
75.04(9)
142.46(10)
76.37(11)
75.35(9)
70.25(11)
80.50(10)
67.09(12)
66.00(11)
140.75(11)
143.46(10)
80.83(10)
139.89(10)
77.99(11)
120.97(9)
61.92(10)
68.86(10)
49.05(8)
O(9)#1–Ce(1)–O(10) 110.82(8)
O(12)–Ce(1)–O(10)
O(8)–Ce(1)–O(9)
O(6)–Ce(1)–O(9)
O(4)–Ce(1)–O(9)
O(13)–Ce(1)–O(9)
O(8)–Ce(1)–C(9)
O(6)–Ce(1)–C(9)
O(4)–Ce(1)–C(9)
O(13)–Ce(1)–C(9)
O(9)–Ce(1)–C(9)
O(2)–Ce(1)–Pd(1)
O(9)#1–Ce(1)–Pd(1)
O(12)–Ce(1)–Pd(1)
O(10)–Ce(1)–Pd(1)
C(9)–Ce(1)–Pd(1)
O(7)–Pd(1)–O(1)
O(7)–Pd(1)–O(5)
O(1)–Pd(1)–O(5)
O(3)–Pd(1)–Ce(1)
O(5)–Pd(1)–Ce(1)
C(1)–O(2)–Ce(1)
C(3)–O(4)–Ce(1)
C(5)–O(6)–Ce(1)
C(7)–O(8)–Ce(1)
C(9)–O(9)–Ce(1)
C(9)–O(10)–Ce(1)
O(10)–C(9)–Ce(1)
C(10)–C(9)–Ce(1)
72.40(10)
120.74(9)
116.81(9)
123.84(9)
67.80(11)
136.94(10)
99.58(10)
135.98(10)
71.93(12)
24.68(9)
99.80(11)
86.46(9)
67.94(10)
24.39(10)
58.54(7)
59.31(8)
58.84(7)
60.54(7)
120.75(6)
114.55(8)
128.44(6)
152.77(7)
176.19(13)
88.65(16)
90.74(16)
91.45(10)
93.16(9)
144.0(3)
140.8(3)
145.4(3)
146.8(3)
108.64(9)
175.59(6)
90.80(16)
89.51(16)
175.38(13)
91.92(9)
91.88(10)
118.5(3)
121.7(3)
118.8(3)
118.0(3)
147.9(2)
118.08(10)
141.6(3)
93.4(2)
97.4(2)
58.23(19)
175.4(3)
Fig. 10. Molecular structure of the complex Pd2Cu(l-OOCMe)6 (8) with
thermal ellipsoids drawn at 30% probability level. The Pd and Cu atoms
are disordered over the coordination triangle (multiplicity of general
positions) Pd(0.7)/Cu(0.3) and of special position (mirror plane) Pd(0.3)/
Cu(0.2).
61.91(19)
Symmetry transformations used to generate equivalent atoms: #1:
ꢀx + 1, ꢀy + 2, ꢀz + 2; #2: ꢀx + 1, ꢀy + 3, ꢀz + 3.

N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
2085
Table 10
tions of band maxima and the emax values for complexes 1–
7 do not change in the same concentration range giving evi-
dence of their stability in solution.
˚
Selected bond lengths (A) and angles (ꢁ) in complex 8
Bond lengths
M(1)–O(3)
M(1)–O(6)
M(1)–O(5)
M(1)–M(2)
1.953(7)
1.974(7)
1.982(7)
M(1)–O(1)
M(1)–M(1)#1
M(2)–O(2)
1.981(6)
3.1097(17)
1.982(7)
1.997(7)
4. Conclusions
3.1231(14) M(2)–O(4)
Our study showed that the double-bridged trinuclear
structure of palladium(II) acetate can easily undergo a
nucleophilic attack by a terminal acetate group of the
mononuclear complexes of divalent transition metals
(e.g., MnII, CoII, NiII, CuII, ZnII) and trivalent rare-earth
metals (e.g., NdIII, EuIII, CeIII) to give rise to the mixed-
metal di-, tri- and tetranuclear complexes in which the
square-planar moiety [Pd(l-OOCMe)4] serves a function
of the structure-determining building block. The fact that
the prepared mixed-metal complexes involve not only the
3d- but also 4f-metals suggests the reaction to be of general
occurrence. In most cases (except for CuII) the complexes
have a ‘‘face-to-face’’ arrangement of the PdII and MII,III
coordination planes. Unlike this, in the PdII–CuII acetate
complexes the PdII and CuII coordination planes are turned
60ꢁ to each other.
Bond angles
O(3)–M(1)–O(1)
O(1)–M(1)–O(6)
O(2)–M(2)–O(2A)a
O(4)–M(2)–O(4A)a
92.1(3)
86.3(3)
84.7(5)
87.0(5)
O(3)–M(1)–O(5)
O(6)–M(1)–O(5)
O(2)–M(2)–O(4)
86.8(3)
91.7(3)
92.5(3)
M(1A)a–M(1)–M(2) 60.142(19)
M(1A)a–M(2)–M(1) 59.72(4)
M(1)–Pd(0.7)/Cu(0.3); M(2)–Pd(0.3)/Cu(0.2).
a
Symmetry transformation used to generate equivalent atoms
x, ꢀy + 3/2, z.
The geometry of complex 8 (Fig. 10) was found to
be very close to that of the trinuclear Pd3 carb-
oxylates [30–33]. The positions of Pd and Cu
atoms in the structure of complex 8 are disor-
dered over the coordination triangle (see Section
2). Both palladium(II) and copper(II) atoms have
almost identical square-plane coordination with
practically equal Pd–O and Cu–O interatomic
The PdII and CuII acetates are known to be a basis of the
catalyst for homogeneous olefin oxidation and oxidative
acetoxylation [6–12]. We believe that the found PdII–CuII
complexation in this catalytic system should be taken into
account when analysing the kinetic and mechanistic data
on the catalytic reactions.
˚
distances (1.938(4)–1.959(4) A) and O–Pd(Cu)–O
angles (84.7(5)–92.5(3)ꢁ, Table 10).
The metal–metal interatomic distances in the com-
plexes under question also engage our attention. Accord-
ing to the X-ray diffraction data, the PdII–MII,III
distances in the four-bridged complexes are very close
to the sum of the corresponding covalent radii, whereas
in the double-bridged PdII–CuII complexes the distances
3.3. Behaviour in solution
Most of the synthesized complexes are well soluble in
acetic acid and, except for complex 8, are stable for a long
time at room temperature and for at least 3–5 h at 70 ꢁC, as
evidenced by the UV–Vis spectra. The formation of hetero-
metallic complexes is accompanied by noticeable changes
in the UV–Vis spectra. For instance, the d–d band of pal-
ladium(II) shifts from 398 to 335 nm on going from
Pd3(OOCMe)6 to complex 2 and the extinction coefficient,
˚
have a normal value of ꢂ3.1 A. The formation of direct
metal–metal bonds between the divalent palladium and
two- or three-valent transition metals seem to be unli-
kely. Meanwhile, a weak electron interaction cannot a
priori be ruled out and, therefore, needs a special
investigation.
e
max, increases from 0.24 · 103 to 1.9 · 103 l molꢀ1 cmꢀ1
(Table 11).
The UV–Vis spectrum of complex 8 dissolved in acetic
The above-examined heterodimetallic PdII-based com-
plexes are of interest not only for catalysis and the coordi-
nation chemistry of these metals but also as promising
starting materials for the synthesis of heterometallic
nanomaterials. Earlier [34,35] we have synthesized a palla-
dium giant cluster with the idealized formula Pd561phe-
n60(OAc)180 by the reduction of Pd3(OOCMe)6 in acetic
acid containing a dozed amount of 1,10-phenanthroline
(phen) as stabilizing ligand. The Pd giant cluster and iꢀts
acid do not obey the Beer–Lambert law in the concentra-
tion range from 3 · 10ꢀ3 to 0.5 · 10ꢀ3 mol lꢀ1, and the
complex slowly transforms to the monometallic compo-
nents and other PdII–CuII complexes. Unlike this, the posi-
Table 11
UV–Vis spectral characteristics for complexes 1–3 and 8
Complex
d–d band
CT band
k (nm) e (l molꢀ1 cmꢀ1
)
k (nm) e (l molꢀ1 cmꢀ1
)
derivatives containing different acido ligands (PF6
,
OHꢀ, O2ꢀ, etc.) but preserving the [Pd561phen60] cluster
core exhibited high catalytic performance in various reac-
tions under mild conditions [34] and specific thermomag-
netic behaviour [36].
Pd3(OOCMe)6 398
245
1600
1900
1100
680
256
250
250
250
265
1900
3000
3000
2012
1500
1
335
325
340
385
2
3
8a
A similar synthetic approach can be used for the prepa-
ration of bimetallic nanoclusters starting from the PdII-
based heterodimetallic complexes. In particular, it would
a
The initial kmax and emax values for complex 8 measured within 3–5 min
after dissolution in acetic acid.

2086
N.Yu. Kozitsyna et al. / Inorganica Chimica Acta 359 (2006) 2072–2086
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be of interest to reveal whether the complementary metal
can enter the cluster core to form an alloy nanoparticle
or it will serve as extra ligand for the Pd giant cluster.
These studies are in progress in our group now.
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The authors thank for financial support the Russian
Foundation for Basic Research (Projects Nos. 05-03-
32983 and 06-03-32578), the Foundation of President of
the Russian Federation (program for support of leading
Russian scientific schools, Grant NSh-4959.2006.03), and
the Russian Academy of Sciences (program for Basic Re-
search ‘‘Purposeful synthesis of inorganic substances and
creation of related functional materials’’). We also thank
Prof. Alexander E. Gekhman, Prof. Zhanna V. Dobrok-
hotova, (Kurnakov Institute, Moscow), and Prof. Vladimir
N. Ikorsky (International Tomographic Center, Novosi-
birsk) for fruitful discussions and advises.
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