Synthesis and characterization of triosmium-bis[60]fullerene and bis(metal cluster)[60]fullerene compounds

Article abstract of DOI:10.1080/15421406.2016.1201404

Triosmium-bis[60]fullerene compound containing dppm ligand, Os₃(CO)₇(dppm)(C₆₀)₂ (1), was synthesized by reaction of Os₃(CO)₉(μ₃-η²:η²:η²-C₆

Full text of DOI:10.1080/15421406.2016.1201404

Molecular Crystals and Liquid Crystals
ISSN: 1542-1406 (Print) 1563-5287 (Online) Journal homepage: http://www.tandfonline.com/loi/gmcl20
Synthesis and characterization of triosmium-
bis[60]fullerene and bis(metal cluster)[60]fullerene
compounds
Bo Keun Park
To cite this article: Bo Keun Park (2016) Synthesis and characterization of triosmium-
bis[60]fullerene and bis(metal cluster)[60]fullerene compounds, Molecular Crystals and Liquid
Crystals, 636:1, 155-158, DOI: 10.1080/15421406.2016.1201404
To link to this article: http://dx.doi.org/10.1080/15421406.2016.1201404
Published online: 01 Nov 2016.
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Date: 06 August 2017, At: 15:53

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
, VOL. , –
http://dx.doi.org/./..
Synthesis and characterization of triosmium-bis[]fullerene
and bis(metal cluster)[]fullerene compounds
Bo Keun Park
Center for Thin Film Materials, Korea Research Institute of Chemical Technology, Yuseong, Daejeon, Republic of
Korea
ABSTRACT
KEYWORDS
fullerene; bis(metal cluster);
osmium; rhenium
Triosmium-bis[60]fullerene compound containing dppm ligand,
Os3(CO)7(dppm)(C60)2 (1), was synthesized by reaction of Os3(CO)9(μ3-
η2:η2:η2-C60) and dppm ligand with Me3NO/MeCN. Reaction of Os3(CO)7
(1,2-dppm)(μ3-η2:η2:η2-C60) and Re3(μ-H)3(CO)11(NCMe) produced
bis(metal-cluster)[60]fullerene
compound,
[Os3(CO)7(1,2-dppm)]
(μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9] (2). Compounds 1 and 2 were charac-
terized by IR, NMR (1H and 31P), and Mass. Electrochemical property of 1
was confirmed by cyclic voltammetry (CV).
Introduction
The researchers have been interested in the fullerene compounds due to their potential
application in optical, magnetic, electronic, catalytic, and biological fields [1–5]. The metal
cluster-C60 compounds with μ3-η2:η2:η2-C60 bonding mode are remarkably thermal stable
and electronic communication between C60 and metal centers [4, 5]. Moreover, the reported
(metal cluster)-bis[60]fullerene sandwich compounds showed strong electronic communica-
tion between the two C60 [5, 6]. The electrochemical properties of the compounds can be read-
ily fine-tuned by change of ligands attached to the metal center [4, 5]. C60 compounds coordi-
nated to two different metal clusters, [Os3(CO)6(PMe3)3](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9]
(cis-1 and cis-2 compounds), were reported with their synthetic methods, characterization,
DFT calculation, and electrochemical properties [7]. Recently, I and co-workers reported the
preparation and electrochemical properties of Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) and
Os3(CO)7(1,1-dppm)(μ3-η2:η2:η2-C60) [8]. Herein, I report the triosmium-bis[60]fullerene
compound containing dppm ligand, Os3(CO)7(dppm)(C60)2 (1), which were prepared
through the synthetic method of Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) and Os3(CO)7(1,1-
dppm)(μ3-η2:η2:η2-C60). Also, I present the bis(metal-cluster)[60]fullerene compound,
[Os3(CO)7(1,2-dppm)](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9] (2). Compounds 1 and 2 were
1
characterized by spectroscopic methods (IR, H-NMR, and Mass). And, the electrochemi-
cal properties of 1 were investigated by cyclic voltammetry (CV).
CONTACT Bo Keun Park
parkbk@krict.re.kr
nology,  Gajeong-ro, Yuseong, Daejeon , Republic of Korea.
Center for Thin Film Materials, Korea Research Institute of Chemical Tech-
©  Taylor & Francis Group, LLC

156/[346]
B. K. PARK
Experimental
General comments
Solvents were dried over the appropriate drying agents and distilled immediately before use.
Anhydrous trimethylamine N-oxide was obtained from Me3NO·2H2O (98%, Aldrich) by sub-
limation (three times) at 90-100°C under vacuum. Os3(CO)9(μ3-η2:η2:η2-C60) [9] was pre-
pared by the literature methods. Preparative thin layer plates were prepared with silica gel
GF254 (Type 60, E. Merck).
Preparation of Os3(CO)7(dppm)(C60)2 (1)
An acetonitrile solution of anhydrous Me3NO (1.5 mg, 0.0196 mmol) was added dropwise
to a chlorobenzene solution (20 mL) of Os3(CO)9(μ3-η2:η2:η2-C60) (30 mg, 0.0194 mmol) at
0°C. The reaction mixture was allowed to warm to room temperature for 30 min. After evapo-
ration of the solvent in vacuo, the residue was dissolved in chlorobenzene (20 mL) containing
dppm (30 mg, 0.0780 mmol). The resulting solution was heated at 60°C for 4 h. Evaporation
of the solvent and purification by multiple elution method (three times) on preparative TLC
(CS2/CH2Cl2 = 15:1) produced Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) (15 mg, 0.0080 mmol,
41%, Rf = 0.6) as a brownish green solid [8], compound Os3(CO)7(1,1-dppm)(μ3-η2:η2:η2-
C60) (12 mg, 0.0064 mmol, 33%, Rf = 0.5) as a green solid [8], and compound 1 (5 mg,
0.0019 mmol, 10%, Rf = 0.4) as a brown solid. IR(CH2Cl2): νCO 2025 (vs), 1964 (s), 1944 (sh),
1923 (w) cm−1; 1H NMR (400 MHz, C6D4Cl2, 298 K): δ 7.76-7.12 (m, 20H, phenyl), 6.56 (dt,
1H, JHH = 15.6 Hz, JPH = 8.3 Hz, PCH2P), 4.43 (dt, 1H, JHH = 15.6 Hz, JPH = 11.5 Hz, PCH2P);
31P{1H} NMR (122 MHz, C6D4Cl2, 298 K): δ −34.7 (d, 1P, JPP = 8.1 Hz, PCH2P), −51.0 (d,
1P, JPP = 8.1 Hz, PCH2P); MS (MALDI-TOF): m/z: 2592.
Preparation of [Os3(CO)7(1,2-dppm)](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9] (2)
Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) (10 mg, 0.0053 mmol) and Re3(μ-H)3(CO)11(NCMe)
(10 mg, 0.011 mmol) were dissolved in chlorobenzene (20 mL). The solution was refluxed
for 2 h. After cooling at room temperature, evaporation of the solvent and purification by
multiple elution method on preparative TLC (CS2/CH2Cl2 = 10:1) produced compound 2
(4 mg, 0.0015 mmol, 28%, Rf = 0.4) as a brown solid. IR (CH2Cl2) νCO 2095 (m), 2076 (m),
2050 (m), 2031 (vs), 2007 (vs), 1975 (s) cm−1; 1H NMR (1,2-C6D4Cl2, 298 K) δ 7.84 – 7.20
(m, 20H, Ph2PCH2PPh2), 5.85 (dt, 1H, JHH = 12.5 Hz, JPH = 12.5 Hz, PCH2P), 4.91 (dt, 1H,
JHH = 12.5 Hz, JPH = 12.5 Hz, PCH2P), −15.31 (s, 1H, μ-H), −15.50 (s, 1H, μ-H), −15.65 (s,
1H, μ-H); 31P{1H} NMR (1,2-C6D4Cl2, 298 K): δ −18.6 (d, 1P, JPP = 32.8 Hz, PCH2P), −22.5
(d, 1P, JPP = 32.8 Hz, PCH2P); MALDI TOF : m/z 2685.
Results and discussion
Compound 1 (10%) with Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) [8] and Os3(CO)7(1,1-
dppm)(μ3-η2:η2:η2-C60) [8] was produced by decarbonylation of Os3(CO)9(μ3-η2:η2:η2-C60)
with Me3NO/MeCN and then subsequent reaction with dppm in CB at 60°C (Scheme 1).

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
[347]/157
Scheme . Synthesis of 1 and 2.
Reaction of Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) and Re3(μ-H)3(CO)11(NCMe) in
CB at reflux temperature gave bis(metal-cluster)[60]fullerene compound, [Os3(CO)7(1,2-
dppm)](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9] (2) (28%) (Scheme 1). The MALDI TOF mass
spectra showed molecular ion isotope multiplets at m/z 2592 for 1 and 2685 for 2.
The 1H NMR spectra of 1 and 2 show two doublet of triplet (dt) patterns with an intensity
ratio of 1:1 in methylene region due to phosphorous atoms and diastereotopicity of metal
combined dppm ligand. For 1, the spectra displays dt peaks at δ 6.56 (JHH = 15.6 Hz, JPH
=
8.3 Hz) and 4.43 (JHH = 15.6 Hz, JPH = 11.5 Hz). 1H NMR spectra of 2 shows dt patterns at δ
5.85 (JHH = 12.5 Hz, JPH = 12.5 Hz) and 4.91 (JHH = 12.5 Hz, JPH = 12.5 Hz) that is slightly
downfield shift than methylene proton peaks of Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) (5.55
(JHH = 14.3 Hz, JPH = 10.7 Hz) and 4.51 (JHH = 14.4 Hz, JPH = 12.6 Hz)) [8]. Also, 1H NMR
spectra of hydride protons for rhenium cluster part reveal three singlets with 1:1:1 intensity
ratio at δ −15.31, −15.50, and −15.65. The 31P{1H} NMR spectra exhibit two doublets at δ
−34.7 and −51.0 (JPP = 8.1 Hz) for 1, and −18.6 and −22.5 (JPP = 32.8 Hz) for 2 because
two phosphine parts of dppm ligand are different environment. 31P NMR spectra for starting
compound, Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60), of 2 show a singlet at δ −19.4 [8].
Cyclic voltammogram (CV) of 1 is shown to Figure 1. Half-wave potentials (E1/2) of
free C60 [5], Rh6(CO)5(dppm)2(CNCH2Ph)(μ3-η2:η2:η2-C60)2 (3) [10], Ir4(CO)3(μ4-CH)-
(PMe3)2(μ-PMe2)(CNCH2Ph)(μ-η2:η2-C60)(μ4-η1:η1:η2:η2-C60) (4) [5], and 1 are provided
in Table 1.
Figure . Cyclic voltammograms of 1 in dry deoxygenated ,-dichlorobenzene (. M [(n-Bu)N][ClO]). Scan
rate =  mV/s.

158/[348]
B. K. PARK
Table . Half-Wave Potentials (E/ vs E°Fc/Fc+) of Free C, 3, 4, and 1.
/−
−/−
−/−
−/−
−/−
−/−
−/−
E/
E/
E/
E/
E/
E/
E/
solvent
C
1
− .
− .
− .
− .
− .
− .
− .
− .
− .
− .
− .
− .
− .
CB
CB
CB
CB
− .
− .
− .
− .
− .
− .
− .a
3
− .
− .
4
aTwo-electron process and peak potential of irreversible process.
CV of 1 exhibits five-well separated, reversible, one-electronic redox couples at −1.14,
−1.35, −1.49, −1.83, and −2.03 V and one irreversible two-electron redox wave at −2.56 V.
The five electron redox waves are sequentially added into the two C60 moieties such as C60-
Os3-C60−, C60−-Os3-C60−, C60−-Os3-C602−, C602−-Os3-C602−, and C602−-Os3-C603−. Similar
behaviors were reported bis[60]fullerene compounds, 3 and 4, and the reversible reduction
potentials of 1 show anodic shifts compared to those of 3 and 4. The irreversible two-electron
reduction (−2.56 V) is considered to show due to instability of the compound with high neg-
ative charge.
Conclusion
Triosmium-bis[60]fullerene (Os3(CO)7(dppm)(C60)2, 1) and bis(metal cluster)[60]fullerene
([Os3(CO)7(1,2-dppm)](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9], 2) was synthesized and charac-
terized. Electrochemical property of 1 are anodic shift and less stability than those of reported
bis[60]fullerenes (Rh6(CO)5(dppm)2(CNCH2Ph)(μ3-η2:η2:η2-C60)2 (3) and Ir4(CO)3(μ4-
CH)(PMe3)2(μ-PMe2)(CNCH2Ph)(μ-η2:η2-C60)(μ4-η1:η1:η2:η2-C60) (4)).
Acknowledgments
This research was supported by a grant from Development of Metal-Chalcogen Fullerene Hybrid Mate-
rials (KK-1407-B7) and the Development of Organometallics and Device Fabrication for IT·ET Con-
vergence (KK-1502-H00) through the Korea Research Institute of Chemical Technology (KRICT).
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