1. ORIGINAL PAPER
Synthesis and Molecular Structure of Redox Active
Platinum–Bis(Telluroferrocenyl) Complex and its
Chelated Rhenium-Chloro(Tricarbonyl) Derivative
Alexander A. Pasynskii • Yury V. Torubaev •
Alina Pavlova • Ivan V. Skabitsky • Gleb Denisov •
Vitaly A. Grinberg
Received: 17 April 2014
Ó Springer Science+Business Media New York 2014
Abstract A new chelating metalloligand (dppe)Pt(TeFc)2 (Fc = ferrocenyl) (1)
was synthesized and used to prepare a mixed-metal tellurate-brigded complex
(dppe)Pt(l-TeFc)2Re(CO)3Cl (2). Both compounds were structurally and electro-
chemically investigated. Details of their molecular structure and CVA are discussed.
Keywords Mixed-metal complexes Á Cluster Á Ferrocenyltelluride Á Platinum Á
Rhenium Á Electrochemistry Á X-ray analyses
Introduction
Chelating metalloligands proved to be efficient as a ‘‘building blocks’’ in the
targeted fabrication of mixed-metal clusters. In contrast to a vast number platinum-
sulfide clusters [1] and thiolate-chelates there are just a few structural reports of
Pt-organotellurium mixed metal complexes [2] where Pt atom usually appeared as a
chelated metal center (Scheme 1a), but not as a part of a chelating metalloligand.
Electronic supplementary material The online version of this article (doi:10.1007/s10876-014-0767-4)
contains supplementary material, which is available to authorized users.
A. A. Pasynskii Á Y. V. Torubaev (&) Á A. Pavlova Á I. V. Skabitsky
N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, GSP-1,
Leninsky Prospect, 31, 119991 Moscow, Russia
e-mail: torubaev@igic.ras.ru
G. Denisov
Higher Chemical College of Russian Academy of Sciences, Miusskaya Sq. 9, 125047 Moscow,
Russia
V. A. Grinberg
A.N.Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
GSP-1, Leninsky Prospect, 31, 119991 Moscow, Russia
123
J Clust Sci
DOI 10.1007/s10876-014-0767-4

2. Recently we have synthesized platinum(II) bis-tellurophenolate (dppe)Pt(TePh)2
and investigated its chelating ability [3] (Scheme 1b).
The replacement of aryl group with the ferrocenyl fragment genereates new
redox active sites in the molecule, increases electron density on chalcogen atom and
can stabilize the electron-deficient complexes [4].
As a part of our ongoing project for the targeted preparation of the mixed-metal
chalcogenide clusters, we have prepared Pt-bis(telluroferrocenyl) complex
(dppe)Pt(FcTe)2 (1) and used it as a chelating metalloligand to synthesize mixed-
metal cluster (dppe)Pt(l-TeFc)2Re(CO)3Cl (2). The presence of two ferrocenyl
groups in each molecule gave interesting opportunity to investigate the electro-
chemical properties.
Results and Discussion
Synthesis
The starting complex 1 was synthesized by analogy with its known congeners in the
reaction of appropriate Pt-dichloride complex with telluroferrocenyl anion generated
in situ. Complex 1 was isolated as air-stable yellow-orange crystalline substance. Its
further treatment with one equivalent of Re(CO)5Cl in boiling toluene allowed the
complex 2—the product of (CO)3ReCl chelation with 1 (Scheme 2) in a form of
yellow-orange crystals.
Ir
Te
Te
Tol
Tol
Cp*
OC
Ir
Te
Te
Tol
Tol
Cp*
OC
PtCl2
(COD)PtCl2
P
Pt
P Te
Te
Ph
Ph
Ph Ph
Ph Ph
P
Pt
P
Te
Te
Ph
Ph
Ph Ph
Ph Ph
[Re(CO)4(µ-Cl)]2
Re(CO)3Cl
(a)
(b)
Scheme 1 Pt as a chelated metal-center (a) and a part of chelating metalloligand ligand (b)
A. A. Pasynskii et al.
123

3. Molecular Structure
The ferrocenyl groups of two cis-TeFc ligands in complex 1 are diverted from one
another in the same fashion as the phenyl groups in (dppe)Pt(TePh)2 [5] and the
cymantrenyl groups in (PPh3)2Pt(SC5H4Mn(CO)3)2 [6]. The pronounced deviation
of Te atom from the plane of the related Cp ring to Fe atom takes place (av. 7°) is
not as deep as (20.3°) observed in [FcTe–TeCl2Fc] [7]. But may result from the
same Fc ? Te dative interaction.
An average interatomic distances Pt-Te in the square-planar coordination
surrounding of Pt center in the molecules 1 (2.62 A˚´
) and 2 (2.65 A˚´
) are within the
range, normally observed in the similar [P]2Pt(TeR)2 complexes [5, 8] but Pt-Te and
Re-Te distances are shorter than the sum of appropriate covalent radii (2.74 and 2.89
A respectively) [9] as a result of dative M ? Te interaction of M lone pare with
vacant orbitals of Te ligand [10] (Figs. 1, 2).
NMR Spectroscopy
1
H NMR spectra of 1 is consistent with its solid state structure. 31
P spectra shows
typical picture for two equivalent phosphines coordinated to the platinum atom,
1
JPt–P coupling constant 2,848 Hz is similar to TePh analogue (2,896 Hz) [5]. 125
Te
signal appears as triplet, possibly due to accidental coincidence of 2
JTe-P (59 Hz)
coupling constants with cis and trans phosphorous atom.
In 1
H spectra of 2 the signals of protons of tellurium-substituted cyclopentadienyl
rings are shifted downfield, possibly as result of electron density withdrawing from
Te atoms at their coordination to rhenium.
1
H NMR spectra of 2 is consistent with anti-arrangement of ferrocenyl groups,
revealed by XRD, showing eight broad apparent singlets of diastereotopic
protons of two nonequivalent TeC5H4 fragmets and two singlets for nonequiv-
alent C5H5 fragments. The broadening of signals could be attributed to inversion
at tellurium atoms or Cl/CO ligands position exchange at rhenium making two
ferrocenyl groups equivalent. The signals of nonequivalent 31
P nuclei at 40.5
(1
JPt–P 2,967 Hz) and 37.4 ppm (1
JPt–P 2,797 Hz) are also broaden due to the
same dynamic process and 2
JP-P coupling constant and 125
Te satellites could not
be observed.
P
Pt
P Te
Te
Fc
Fc
Ph Ph
Ph Ph
P
Pt
P Te
Te
Fc
Fc
Ph Ph
Ph Ph
Re(CO)3Cl
P
PtCl2
P
Ph Ph
Ph Ph
FcTeNa Re(CO)5Cl
Scheme 2 Formation of 1 and 2
Redox Active Platinum–Bis(Telluroferrocenyl) Complex
123

4. Electrochemistry
In the case of complex 1 the irreversible of one-electron oxidation wave at 0.24 V
(Fig. 3) could be a result of a FcTe ligand oxidation and consequent dimerization
(Scheme 3) similar to the process described for (diphos)Pt(SAr)2 in [11].
Three next oxidation waves at 0.67, 0.84 and 0.97 V are quasi- reversible. In the
case of chelated complex there are two reversible one-electron oxidation waves of
ferrocenyl group at 0.48 and 0.59 V (Fig. 4). The nature of the third quasi-reversible
oxidation wave at 1.0 V in 2 is not clear yet and may involve the oxidation of Re or
Pt atoms.
Experimental Part
General Procedure
All reactions and manipulations were performed using standard Schlenk techniques
under an inert atmosphere of argon. Solvents were purified, dried and distilled under
an argon atmosphere prior to use. Re(CO)5Cl [12], (dppe)PtCl2 [13] and Fc2Te2 [14]
were prepared following the published procedures. NMR spectra were recorded at
Bruker Avance 300 and Bruker Avance 400 spectrometers.
Fig. 1 The solid state structure of 1 showing its non- hydrogen thermal ellipsoids at the 50 % probability
level. Hydrogen atoms are omitted for clarity. Selected intramolecular distances (A˚´
) P(2)–Pt(1) 2.255(1),
Pt1–P1 2.258(1), Pt1–Te1 2.6091(5), Pt1–Te2 2.6254(5), Te2–C1 1.109(6), Te1–C1 2.113(4), Te1–Fe1
3.6116(8), Te2–Fe2 3.578(1), Te2–C41 3.399(5), Te2–C42 3.687(6), Te2–C46 3.986(6), Te1–C11
3.364(6), C15–Te1 3.527(6), Te1–C12 4.182(7), and bond angles (°): P(2)–Pt(1)–P1 85.45(5),
Te(2)–Pt(1)–Te1 88.79(1), Cpplane–Te(1) 173.82 Cpplane–Te(2) 172.57
A. A. Pasynskii et al.
123

5. Fig. 2 The solid state structure of 2 showing its non-hydrogen thermal ellipsoids at the 50 % probability
level. Hydrogen atoms are omitted for clarity. Selected intramolecular distances (A˚´
) Pt(1)–P(2) 2.263(2),
Pt(1)–P(1) 2.266(2), Pt(1)–Te(4) 2.6578(5), Pt(1)–Te(3) 2.6389(7), Te(3)–Re(2) 2.7948(5), Re(2)–Te(4)
2.7899(6), Re(2)–Cl(1) 2.481(3), Te(4)–Fe(5) 3.593(1), Te(3)–Fe(1) 3.657(1), and bond angles (°):
P(2)–Pt(1)–P(1) 86.20(6), Te(4)–Pt(1)–Te(3) 82.35(2), Pt(1)–Te(4)–Re(2) 92.60(2), Re(2)–Te(3)–Pt(1)
92.89(2)
-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2
-2
0
2
4
6
8
10
E / V vs. Ag
I / µA
Fig. 3 Cyclic voltammogram for complex 1 (2.4 mM) in the potentials range from -0.2 to 1.13 V on the
glassy carbon (GC) electrode at t = 0.1 V s-1
in CH2Cl2 with 0.2 M Bu4NPF6 as the supporting
electrolyte. Start potential is -0.25 V
Redox Active Platinum–Bis(Telluroferrocenyl) Complex
123

6. Synthesis of (dppe)Pt(TeFc)2 (1)
Benzophenone 0.02 g (0.11 mmol) and the suspension of sodium (0.3 g, 13.04 mmol)
in 10 mL THF were added subsequently to the magnetically stirred red solution
Fc2Te2 (0.2 g, 0.32 mmol) at room temperature. After stirring for 2, 5 h reaction
mixture turned greenish-yellow and was filtrated to the solid (dppe)PtCl2 (0.21 g
(0.32 mmol) and stirring for additional 3 h. The solvent was eliminated from resulting
orange-red reaction mixture under reduced pressure and the orange oily residue was
washed with heptane (2 9 5 mL), extracted with THF (10 mL) and filtrated. THF
filtrate was diluted with heptane (4 mL), concentrated under reduced pressure to 1/3 of
initial volume and kept at -15 °C for 24 h to provide yellow precipitate. Yield 0.27 g
(70 %).
The crystals suitable for the single-crystal XRD analysis were grown from the
NMR sample of 1 in CDCl3 layered with hexane.
P
Ph2
Pt
Ph2
P Te
Te
Fc
Fc
Pt
Te
Fc
-1e-
Ph2
P
P
Ph2
Pt
Te
Fc
P
Ph2
Ph2
P
2
2+
Scheme 3 Suggested mechanism for one-electron oxidation of (dppe)Pt(FcTe)2
-0.5 0.0 0.5 1.0 1.5 2.0
-10
-5
0
5
10
15
20
I / µA
E / V vs. Ag
Fig. 4 Cyclic voltammogram for complex 2 (3.4 mM) in the potentials range from -0.25 to 1.7 V on the
glassy carbon (GC) electrode at t = 0.1 V s-1
in CH2Cl2 with 0.2 M Bu4NPF6 as the supporting
electrolyte. Start potential is -0.25 V
A. A. Pasynskii et al.
123

7. IR spectra (KBr, m, cm-1
,): 1103, 736, 692, 532. Anal. Calc. for 1(C46H42Fe2-
P2PtTe2): C 45.33, H 3.47 %; Found: C 44.52, H 3.76 %.
1
H NMR (300 MHz, CDCl3, d ppm): 1.87 (m, 4H, Ph4P2C2H4), 3.66 (m, 4H,
C5H4), 3.77 (m, 4H, C5H4), 3.95 (s, 10H C5H5), 7.05–7.78 (m, 20H, Ph4P2C2H4).
31
P NMR (121.5 MHz, CDCl3, d ppm): 44.94 (1
JPt–P = 2848 Hz, 2
JTe-P =
59 Hz).
125
Te NMR (94.7 MHz, CDCl3, d ppm): 65.2 (apparent triplet, 2
JTe-P = 59 Hz).
Synthesis of dppePt(l-TeFc)2Re(CO)3Cl (2)
Solid Re(CO)5Cl (0.042 g, 0.115 mmol) was stirred at 60 °C for 1 h in dry toluene
(10 mL) until almost complete dissolution and after addition of solid (dppe)Pt(FcTe)2
(0.14 g, 0.115 mmol) the reaction mixture was refluxed for 1 h. Then cooling to room
temperature gave an oily precipitate which solidified at pest ling with heptane (3 mL).
The solution with solidified orange residue was heated to the boiling temperature and
slowly cooled in an oil bath to room temperature resulting well-formed orange prisms
suitable for the single-crystal XRD analysis.
Yield 0.143 g (82 %). Sample for NMR and elemental analysis was recrystal-
lized from CH2Cl2/hexane mixture.
IR-spectrum (KBr, m, cm-1
): 2003, 1898, 1870, 1105, 821, 690, 531. Anal.Calc.
for 2 (C49H42ClFe2O3P2PtReTe2): C 38.61, H 2.78 %; Found: C 38.68, H 3.54 %.
1
H NMR (400 MHz, CDCl3, d ppm): 1.71–1.24 (br. m., 4H, Ph4P2C2H4), 2.89 (br.
s., 1H, C5H4), 3.27 (br. s., 1H, C5H4), 3.58 (br. s., 1H, C5H4), 3.77 (br. s., 1H, C5H4),
4.01 (br. s., 1H, C5H4), 4.11 (s, 5H, C5H5), 4.15 (s, 5H, C5H5), 4.21 (br. s., 1H, C5H4),
4.40 (br. s., 1H, C5H4), 4.67(br. s., 1H, C5H4), 7.30–7.81 (m, Ph4P2C2H4).
31
P NMR (162.0 MHz, CDCl3, d ppm): 37.8 (br. 1
JPt–P 2987 Hz), 41.0 (br. 1
JPt–P
2790 Hz).
Crystal Structure Determination of Compound 1 and 2
Relevant crystallographic data and details of measurements are given in Table 1.
A Bruker APEX II CCD area detector diffractometer equipped with a graphite-
monochromated Mo Ka radiation (0.71070 A˚ ) was used for the cell determination
and intensity data collection for compound 1 and 2. The structure was solved by
direct methods (SHELXS-97) and refined by full-matrix least squares against F2
using SHELXL-97 software [15]. Non-hydrogen atoms were refined with
anisotropic thermal parameters. All hydrogen atoms were geometrically fixed and
refined using a riding model.
Electrochemistry
The cyclic voltammograms (CV) of complexes 1 and 2 were recorded on a PAR 273
potentiostat/galvanostat (Princeton Applied Research) with the standard software.
The measurements were carried out in a thermostatically controlled three-electrode
electrochemical cell under a high purity argon atmosphere. A SU-2000 (0.0078 cm2
)
glassy carbon disk pressed in Teflon served as the working electrode and a platinum
Redox Active Platinum–Bis(Telluroferrocenyl) Complex
123

8. grid (1 cm2
) was used as the auxiliary electrode. The potentials were measured versus
the silver reference electrode in the same solution. The measurements were carried out
in dichloromethane with 0.2 M Bu4NPF6 as the supporting electrolyte. The potential
sweep rates were in the range from 0.050 to 1.0 V s-1
.
Table 1 Crystal data and structure refinement for compounds 1,2
Compound 1 2
Empirical formula C47H43Cl3Fe2P2PtTe2 C49H42ClFe2O3P2PtReTe2
Formula weight 1338.09 1524.41
Temperature, K 153(2) 150(2)
Wavelength (A˚´
) 0.71073
Crystal system Triclinic
Space group P-1
Unit cell dimensions
a (A˚´
) 11.5498(13) 11.7331(12)
b (A˚´
) 14.1088(15) 12.5142(13)
c (A˚´
) 14.6890(17) 18.701(2)
a (°) 100.885(2) 71.808(2)
b (°) 97.291(2) 81.442(2)
c (°) 92.558(2) 63.644(2)
Volume (A˚´ 3
) 2,325.8(4) 2,337.3(4)
Z 2 2
Density (calculated)
(mg/m3
)
1.911 2.166
Absorption coefficient (mm-1
) 5.118 7.563
F(000) 1,280 1,432
Theta range for data collection (°) 2.12–29.00. 2.07–27.50
Index ranges -15 B h B 15,
-19 B k B 19,
-20 B l B 19
-15 B h B 15,
-16 B k B 16,
-24 B l B 24
Reflections collected 25,446 20,847
Independent reflections 12,251 [R(int) = 0.0378] 10,598 [R(int) = 0.0259]
Absorption correction Semi-empirical from equivalents
Max. and min. transmission 0.784 and 0.629 0.5829 and 0.3596
Refinement method Full-matrix least-squares on F2
Data/restraints/parameters 12,251/0/514 10,598/0/550
Goodness-of-fit on F2
1.009 0.831
Final R indices [I [ 2sigma(I)] R1 = 0.0413, wR2 = 0.1024 R1 = 0.0361, wR2 = 0.1050
R indices (all data) R1 = 0.0547, wR2 = 0.1105 R1 = 0.0488, wR2 = 0.1156
Largest diff. peak and hole, e (A˚´ -3
) 4.788 and -1.310 2.891 and -1.472
A. A. Pasynskii et al.
123

9. Acknowledgments We gratefully acknowledge the financial support from the Russian Foundation for
Basic Research (Grant 13-03-92691, 12-03-00860, 13-03-12415) and RF President Fellowship (MK
5635.2013.03).
Appendix A
Atomic coordinates and other structural parameters of 1–2 have been deposited with
the Cambridge Crystallographic Data Center (nos. CCDC 997651 (1), CCDC
997652 (2).
Supplementary data associated with this article can be found, in the online
version, at https://www.ccdc.cam.ac.uk/services/structure_deposit/.
References
1. T. S. A. Hor (1996). J. Cluster Sci. 3, 263.
2. T. Nakagawa, H. Seino, and Y. Mizobe (2010). J. Organomet. Chem. 695, 137.
3. A. A. Pasynskii, Yu. V. Torubaev, A. V. Pavlova, S. S. Shapovalov, I. V. Skabitsky, and G.
L. Denisov (2014). Russ. J. Coord. Chem. 40(09), P000. doi:10.7868/S0132344X14090060.
4. I. V. Skabitsky, Yu V Torubaev, Zh V Dobrokhotova, and E. V. Krasil’nikova (2005). Russ. J. Inorg.
Chem. 50, 1197.
5. M. Risto, E. M. Jahr, M. S. Hannu-Kuure, R. Oilunkaniemi, and R. S. Laitinen (2007). J. Organomet.
Chem. 692, 2193.
6. A. A. Pasynskii, I. V. Skabitsky, and Yu V Torubaev (2005). Russ. Chem. Bull. 54, 1552.
7. Y. Torubaev, P. Mathur, M. Tauqeer, M. M. Shaikh, G. K. Lahiri, A. Pasynskii, A. Pavlova, and V.
Grinberg (2014). J. Organomet. Chem. 749, 115.
8. N. V. Kirij, W. Tyrra, I. Pantenburg, D. Naumann, H. Scherer, D. Naumann, and Yu L Yagupolskii
(2006). J. Organomet. Chem. 691, 2679.
9. B. Cordero, V. Gromez, A. E. Platero-Prats, M.Revres, J.Echeverrrıa, E. Cremades, F. Barragran and
S. Alvarez (2008) Dalton. Trans. 2832.
10. A. Pasynskii (2011). Russ. J. Coord. Chem. 37, 801.
11. S.-K. Lee, O. Jeannin, M. Fourmigue, W. Suh, and D.-Y. Noh (2012). J. Organomet. Chem. 716, 237.
12. E.W. Abel and G. Wilkinson (1959). J. Chem. Soc. 1501.
13. D. A. Slack and M. C. Baird (1977). Inorg. Chim. Acta. 24, 277.
14. Y. Nishibayashi, T. Chiba, J. D. Singh, S. Uemura, and S. Fukuzawa (1994). J. Organomet. Chem.
473, 205.
15. G. M. Sheldrick (2008). Acta. Crystallogr. A64, 112.
Redox Active Platinum–Bis(Telluroferrocenyl) Complex
123