Ternary nanoclusters of CuHgS, CuHgSe, and CulnS

Article abstract of DOI:10.1021/ic0110528

Two copper-mercury-chalcogenide clusters [Hg₁₅Cu₂₀E₂₅(PPr₃)₁₈] (1, E = S; 2, E = Se) are synthesized in good yield from the reaction of (Pr3P)3Cu-ESiMe3 and (Pr₃P)₂·Hg(OAc)₂ at low temperatures. Single-crystal X-ray analyses illustrate that the two ternary clusters are isomorphous and consist of a phosphine-stabilized core of mixed Hg, Cu, and E centers. Thermolysis of 1 leads to the formation of mercury metal and various forms of copper-sulfide. The copper-indium-sulfide cluster [Cu₆In₈S₁₃Cl₄ (PEt₃)₁₂] (3) is similarly prepared in 50% yield from (Et3P)3Cu-SSiMe3, InCl₃, and S(SiMe₃)₂.

Full text of DOI:10.1021/ic0110528

Inorg. Chem. 2002, 41, 5693−5698
Ternary Nanoclusters of CuHgS, CuHgSe, and CuInS
Diem T. T. Tran,† Lianne M. C. Beltran,† Collin M. Kowalchuk,† Nicholas R. Trefiak,†
,†
Nicholas J. Taylor,‡ and John F. Corrigan*
Departments of Chemistry, The UniVersity of Western Ontario, London,
Ontario N6A 5B7, Canada, and UniVersity of Waterloo, Waterloo, Ontario N2L 3G1, Canada
Received October 12, 2001
Two copper−mercury−chalcogenide clusters [Hg15Cu20E (PPr3)18] (1, E ) S; 2, E ) Se) are synthesized in good
25
yield from the reaction of (Pr3P)3Cu−ESiMe3 and (Pr3P)2‚Hg(OAc)2 at low temperatures. Single-crystal X-ray analyses
illustrate that the two ternary clusters are isomorphous and consist of a phosphine-stabilized core of mixed Hg, Cu,
and E centers. Thermolysis of 1 leads to the formation of mercury metal and various forms of copper−sulfide. The
copper−indium−sulfide cluster [Cu6In8S Cl4(PEt3)12] (3) is similarly prepared in 50% yield from (Et3P)3Cu−SSiMe3,
13
InCl3, and S(SiMe3)2.
Introduction
To date the exploration of binary metal-sulfide and
-selenide (ME) nanoclusters has been much more extensive
in contrast to ternary (MM′E) nanoclusters,6 and this may
be attributed, in part, to a lack of suitable “binary” silyl
The continued interest in metal-chalcogenide (M-S,
M-Se, M-Te) semiconductor colloidal and nanocluster
materials and their possible uses in materials applications1
have led to many efforts to access particles in a size-
controlled manner, as exemplified with XII-XVI cluster/
colloid synthesis.2 Silyl chalcogen reagents offer excellent
routes into XI-XVI nanoclusters with well-defined cores
that are suitable for single-crystal X-ray analyses, and the
development of this area of chemistry by Fenske and co-
workers has led to the successful isolation of a large number
of binary metal-chalcogenide nanoclusters, synthesized via
the reaction of metal salts and E(SiMe3)2 (E ) S, Se, Te),
where the formed metal-chalcogenide cores are stabilized
by phosphine ligands.3 (Trimethylsilyl)seleno- and telluro-
ethers (RE-SiMe3, ArE-SiMe3) can also be used for the
generation of other series of novel high-nuclearity (metal-
chalcogenide-chalcogenolate) clusters stabilized with sele-
nolate4 and tellurolate5 surfaces.
(2) For examples of XII-XVI nanocluster and nanoparticle syntheses,
see: (a) Green, M.; O’Brien, P. Chem. Commun. 1999, 2235-2241.
(b) Herron, N.; Wang, Y.; Eckert, H. J. Am. Chem. Soc. 1990, 112,
1322-1326. (c) Dance, I. G.; Choy, A.; Scudder, M. L. J. Am. Chem.
Soc. 1984, 106, 6285-6295. (d) Herron, N.; Calabrese, J. C.; Farneth,
W. E.; Wang, Y. Science 1993, 259, 1426-1428. (e) Steigerwald, M.
L.; Alivisatos, A. P.; Gibson, J. M.; Harris, T. D.; Kortan, R.; Muller,
A. J.; Thayer, A. M.; Duncan, T. M.; Douglass, D. C.; Brus, L. E. J.
Am. Chem. Soc. 1988, 110, 3046-3050. (f) Murray, C. B.; Norris, D.
J.; Bawendi, M. G. J. Am. Chem. Soc. 1993, 115, 8706-8715. (g)
Vossmeyer, T.; Reck, G.; Katsikas, L.; Haupt, E. T. K.; Schulz, B.;
Weller, H. Science 1993, 267, 1476-1479. (h) Adams, R. D.; Zhang,
B.; Murphy, C. J.; Yeung, L. K. Chem. Commun. 1999, 383-384. (i)
Vossmeyer, T.; Reck, G.; Schulz, B.; Katsikas, L.; Weller, H. J. Am.
Chem. Soc. 1995, 117, 12881-12882. (j) Soloviev, V. N.; Eichho¨fer,
A.; Fenske, D.; Banin, U. J. Am. Chem. Soc. 2001, 123, 2354-2364.
(k) Rogach, A. L.; Kornowski, A.; Gao, M. Y.; Eychmu¨ller, A.; Weller,
H. J. Phys. Chem. B 1999, 103, 3065-3069. (l) Talapin, D. V.;
Haubold, S.; Rogach, A. L.; Kornowski, A.; Haase, M.; Weller, H. J.
Phys. Chem. B 2001, 105, 2260-2263.
(3) (a) Eichho¨fer, A.; Corrigan, J. F.; Fenske, D.; Tro¨ster, E. Z. Anorg.
Allg. Chem. 2000, 626, 338-348. (b) Dehnen, S.; Fenske, D. Chem.s
Eur. J. 1996, 2, 1407-1416. (c) Eichho¨fer, A.; Fenske, D. J. Chem.
Soc., Dalton Trans. 1998, 2969-2972. (d) Dehnen, S.; Scha¨fer, A.;
Ahlrichs, R.; Fenske, D. Chem.sEur. J. 1996, 2, 429-435. (e)
Deveson, A.; Dehnen, S.; Fenske, D. J. Chem. Soc., Dalton Trans.
1997, 4491-4497. (f) Fenske, D.; Krautscheid, H.; Balter, S. Angew.
Chem., Int. Ed. Engl. 1990, 29, 796-799. (g) Fenske, D.; Steck, J.-C.
Angew. Chem., Int. Ed. Engl. 1993, 32, 238-240. (h) Krautscheid,
H.; Fenske, D.; Baum, G.; Semmelmann, M. Angew. Chem., Int. Ed.
Engl. 1993, 32, 1303-1305.
* To whom correspondence should be addressed. E-mail: corrigan@
uwo.ca.
† The University of Western Ontario.
‡ University of Waterloo.
(1) For selected recent reviews, see (a) Efros, Al. L.; Rosen, M. Annu.
ReV. Mater. Sci. 2000, 30, 475-521. (b) Eychmu¨ller A. J. Phys. Chem.
B 2000, 104, 6514-6528 (c) Eychmu¨ller A.; Rogach, A. l. Pure Appl.
Chem. 2000, 72, 179-188. (d) Adair, J. H.; Li, T.; Kido, T.; Havey,
K.; Moon. J.; Mecholsky, J.; Morrone, A.; Talham, D. R.; Ludwig,
M. H.; Wang, L. Mater. Sci. Eng. 1998, R23, 139-242. (e) Nirmal,
M.; Brus, L. Acc. Chem. Res. 1999, 32, 407-414. (f) Herron, N.;
Thorn, D. L. AdV. Mater. 1998, 10, 1173-1184. (g) Alivisatos, A. P.
J. Phys. Chem. 1996, 100, 13226-13239. (h) Weller, H. Angew.
Chem., Int. Ed. 1998, 37, 1658-1659. (i) Murphy, C. J. J. Cluster
Sci. 1996, 7, 341-350.
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10.1021/ic0110528 CCC: $22.00 © 2002 American Chemical Society
Published on Web 10/02/2002
Inorganic Chemistry, Vol. 41, No. 22, 2002 5693

Tran et al.
reagents that can be employed to yield ternary clusters. A
general molecular synthetic route to access ternary nano-
clusters is desirable since ternary materials find widespread
applications in optical and electronic devices. For example
Hg1-xCdxTe (x ) 0-1) has been used in IR detection7 and
CuInS2 (Eg ) 1.5 eV) semiconducting thin films display
desirable properties for use in solar cells applications.8
We communicated recently9 that tris(tripropylphosphine)-
copper (trimethylsilyl thiolate), (Pr3P)3Cu-SSiMe3, may be
used as a soluble source of “copper thiolate”, “CuS-”, in
the formation of a mercury-copper-sulfide cluster. Herein
we describe the detailed synthesis and properties of the
ternary clusters [Hg15Cu20S25(PPr3)18] (1), [Hg15Cu20Se25-
(PPr3)18] (2), and [Cu6In8S13Cl4(PEt3)12] (3) using the com-
plexes (R3P)3Cu-ESiMe3 (R ) Pr, Et; E ) S, Se).10
Hg(OAc)2 before reaction with 4a affords only 1, thus
illustrating that the phosphine ligands in the cluster originate
from the chalcogenolate reagent. Although the ratio of Hg:
Cu:S in 1 is 3:4:5, versus the 3:6:6 ratio of these elements
in the reaction mixture, the preformed S-Cu bond in 4a is
required for the formation of 1, as simple mixtures of 1:0.5:5
CuOAc:Hg(OAc)2:PPr3 and S(SiMe3)2 do not generate the
ternary cluster. This contrasts with the synthetic route to the
recently reported copper-indium-selenide clusters, such as
[Cu6In8Se13Cl4(PnPr2Ph)12] (vide infra) which is prepared
from mixing CuCl, InCl3, and Se(SiMe3)2.6a
THF
(Pr3P)3Cu-ESiMe3 + 0.5Hg(OAc)2‚2PPr3 -75 f -30 °C8
[Hg15Cu20E25(PPr3)18] (E ) S (1), Se (2)) +
OAcSiMe3 + PPr3 (1)
Results and Discussion
Phosphine-stabilized mercury-chalcogenide (-olate) and
related clusters, most of which are lower nuclearity com-
plexes such as [Hg6(SePh)12(PtBu3)2],11a display adamantoid
frameworks.11 The nanocluster [Hg32Se14(SePh)36], which has
a metal core consisting of fused adamantane cages, has been
reported and was shown to be a good example of a cluster
displaying the size quantization effect.12 The solid-phase
diffuse reflectance UV-vis analysis of 1 displays a broad,
featureless absorption profile starting at ∼750 nm with no
distinct maximum. This type of absorption profile is char-
acteristic of other copper(I)-chalcogenide nanocluster
complexes.3a
When a solution of 1 is refluxed in toluene at 110 °C for
3 h, a clear, colorless solution results with the concomitant
formation of a black powder and beads of mercury metal.
GC-MS analysis of the volatiles from this treatment indicates
the presence of only SdPPr3. Components of the black
powder consisted of HgS, Cu2S, Cu1.96S, Cu2-xS, and Cu7.2S4
as analyzed by powder X-ray diffraction (Figure S1, Sup-
porting Information).13 This segregation of the two metals
after heating may reflect an instability of HgCuS solids.14
Consistent with these results, thermogravometric analysis of
1 (Figure 1) depicts three decomposition steps starting at
100 °C leading to a total of 78.6% mass loss by 440 °C and
the formation of elemental mercury. This change in mass
cannot be simply explained by the loss of the phosphine
ligands, either as free PPr3 (calcd 36.2%) or SdPPr3 (calcd
43.5%). The visible generation of mercury metal and powder
Due to the labile nature of the phosphine ligands bonded
to the copper center, in conjunction with the expected
reactivity of the E-SiMe3 moiety, we reasoned that the
chalcogenolate reagents synthesized, (R3P)3Cu-ESiMe3,
would serve as a good source of “metallachalcogenolate”
Cu-E-, when reacted with a second metal salt. The
complexes (R3P)3Cu-ESiMe3 [4a, R ) Pr, E ) S; 4b, R )
Pr, E ) Se; 5, R ) Et, E ) S) are prepared in good yield
from the 1:1 reaction of (R3P)3Cu-OAc and E(SiMe3)2 at
low temperatures.10 Thus, when 4a is treated with 0.5 equiv
of (Pr3P)2‚Hg(OAc)2 at -75 °C, orange crystals of [Hg15-
Cu20S25(PnPr3)18] (1) (60% yield) formed after a few hours
at -30 °C (eq 1). These crystals seem to be photosensitive
in that they darken to a black color upon exposure to direct
light and are best stored under an inert atmosphere in the
absence of visible light. Crystals of 1 are otherwise stable
and dissolve in common polar organic solvents with the
addition of excess tripropylphosphine. An X-ray analysis
reveals that 1 is a “pinwheellike” ternary complex with Hg,
Cu, and S centers interspersed in the structure of the 0.7 ×
1.2 × 1.2 nm3 core. The structural details for 1 have been
reported in some detail9 and are not repeated here. The use
of different phosphines (PPhEt2 and PPh2Et) to solubilize
(5) (a) Corrigan, J. F.; Fenske, D. Chem. Commun. 1997, 1837-1838.
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36, 1981-1983. (c) Langetepe, T.; Fenske, D. Z. Anorg. Allg. Chem.
2001, 627, 820-826. (d) Pfistner, H.; Fenske, D. Z. Anorg. Allg. Chem.
2001, 627, 575-582. (e) Semmelmann, M.; Fenske, D.; Corrigan, J.
F. J. Chem. Soc., Dalton Trans. 1998, 2541-2545. (f) Corrigan, J.
F.; Balter, S.; Fenske, D. J. Chem. Soc., Dalton Trans. 1996, 729-
738.
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1245-1246. (b) Dean, P. A. W.; Vittal, J. J.; Wu, Y. Inorg. Chem.
1994, 33, 2180-2186. (c) Dean, P. A. W.; Manivannan, V. Inorg.
Chem. 1990, 29, 2997-3002. (d) Dean, P. A. W.; Manivannan, V.
Can. J. Chem. 1990, 68, 214-222. (e) Dean, P. A. W.; Vittal, J. J.;
Trattner, M. H. Inorg. Chem. 1987, 26, 4245-4251. (f) Arnold, A.
P.; Canty, A. J.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton
Trans. 1982, 607-613. (g) Dean, P. A. W.; Manivannan, V.; Vittal,
J. J. Inorg. Chem. 1989, 28, 2360-2368. (h) Singh, A. K.; Khandelwal,
B. L.; Srivastava, V. Phosphorus, Sulfur, Silicon Relat. Elem. 1990,
48, 169-171. (i) Freedman, D.; Emge, T. J.; Brennan, J. G. J. Am.
Chem. Soc. 1997, 119, 11112-11113.
(12) Behrens, S.; Bettenhausen, M.; Deveson, A. C.; Eichho¨fer, A.; Fenske,
D.; Lohde, A.; Woggon, U. Angew. Chem., Int. Ed. Engl. 1996, 35,
2215-2218.
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University Press: Toronto, Canada, 1984; pp 1142-1145.
(14) Charbonnier, M.; Murat, M. Mater. Res. Bull. 1972, 7, 1473-1483.
(6) (a) Eichho¨fer, A.; Fenske, D. J. Chem. Soc., Dalton Trans. 2000, 941-
944. (b) Li, H.; Kim, J.; Groy, T. L.; O’Keeffe, M.; Yaghi, O. M. J.
Am. Chem. Soc. 2001, 123, 4867-4868. (c) Fenske, D.; Bettenhausen,
M. Angew. Chem., Int. Ed. 1998, 37, 1291-1294.
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(8) (a) Czekelius, C.; Hilgendorff, M.; Spanhel, L.; Bedja, I.; Lerch, M.;
Mu¨ller, G.; Bloeck, U.; Su, D.-S.; Giersig, M. AdV. Mater. 1999, 11,
643-646. (b) Kumar S. R. Indian J. Pure Appl. Phys. 1999, 37, 356-
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Molochko, A. P.; Solovej, N. P. Phys. Status Solidi B 1998, 208, 533-
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5694 Inorganic Chemistry, Vol. 41, No. 22, 2002

Ternary Nanoclusters of CuHgS, CuHgSe, and CuInS
Table 1. Bond Lengths (Å) and Angles (deg) for
[Hg15Cu20Se25(PPr3)18] (2)a
Hg(1)-Se(1)
Hg(1)-Se(2)
Hg(2)-Se(3)
Hg(4)-Se(4)
Hg(5)-Se(3)
Hg(5)-Se(4)
Hg(5)-Se(2)
Se(1)-Cu(2)
Se(1)-Cu(1)
2.4383(17)
2.4421(17)
2.5895(18)
2.341(2)
2.230(3)
2.329(2)
3.018(2)
2.423(3)
2.606(3)
Se(2)-Cu(5)
Se(3)-Cu(5)
Se(4)-Cu(2)
Se(4)-Hg(3)
Se(4)-Cu(3)
Se(4)-Cu(5)
Se(4)-Cu(4)
Se(5)-Hg(3)
Se(5)-Cu(3A)
2.487(4)
2.700(5)
2.394(3)
2.524(5)
2.643(13)
2.666(4)
2.716(4)
2.350(5)
2.574(14)
Se(1)-Hg(1)-Se(2) 179.41(7)
Se(3)B-Hg(2)-Se(3) 118.941(18) Cu(5)-Se(3)-Cu(3A)A
Se(3)C-Hg(4)-Se(4) 147.36(11) Hg(5)-Se(4)-Hg(4)
Se(4)-Hg(4)-Se(1)D 103.59(8)
Se(3)-Hg(5)-Se(4) 149.00(11) Hg(4)-Se(4)-Cu(2)
Hg(2)-Se(3)-Cu(3)B
79.9(3)
63.1(3)
91.85(9)
127.52(11)
126.88(10)
93.42(14)
87.0(2)
67.2(3)
98.36(11)
84.8(2)
Figure 1. Thermogravimetric analysis curve for [Hg15Cu20S25(PPr3)18] (1).
Hg(5)-Se(4)-Cu(2)
X-ray diffraction (Figure S2, Supporting Information) indi-
cate that the remaining crusty gray solid is a mixture of
various forms of copper sulfide which include Cu1.96S,
Cu1.81S, Cu62S32, Cu1.9375S, Cu2S, and Cu7.2S4.13 A GC-MS
analysis of the emitted volatiles (excluding mercury metal)
from the TGA analysis revealed that it consisted of ∼15%
tripropylphosphine and ∼85% of SdPPr3. A calculated
weight loss from 1 from the combined elimination of this
ratio of phosphine/phosphine-sulfide and the mercury
centers (80.0%) is in good agreement with the observed
weight loss (78.6%). Thus, in addition to ligand elimination
from the cluster surface during thermolysis, Hg(0) formation
and elimination also occurs to yield various mixtures of Cu-
(I)/Cu(II)/S solids. Although this illustrates that complexes
such as 1 may not be suitable precursors to related HgII-
CuISx solids due to the facile redox chemistry involved, it
does demonstrate clearly the advantage of the low-temper-
ature synthesis in achieving kinetically controlled mixing of
the three core elements in the cluster complex.
In a similar manner as for the preparation of 1, when
(Pr3P)3Cu-SeSiMe3 (4b) was reacted with tripropylphos-
phine-solubilized Hg(OAc)2, ruby red crystals of [Hg15Cu20-
Se25(PnPr3)18] (2) formed in high yield (>80%) within 24-
48 h at low temperatures. As with 1, the phosphine used to
solubilize the mercury acetate does not affect the cluster
product formed. Unlike its sulfide analogue 1, cluster 2 is
red in color when isolated and only darkens to a black color
after several weeks of exposure to ambient light.
Data from single-crystal X-ray analysis illustrate that 2 is
isostructural (and isomorphous) to 1, and Table 1 summarizes
the structural parameters for 2. The cluster core in 2 is larger
than is observed in 1, 0.7 × 1.5 × 1.5 nm3. The “flattened”
nature of this cluster is illustrated in the projection of 2
(Figure 1). The molecule resides on a crystallographic 3h site
with the 3-fold axis lying along the Hg2-Se5 vector. About
the central selenide (Se5) there is some disorder, where in
which the Hg3 and Cu3 are distributed over six equivalent
sites. At any particular time there are two copper sites and
one mercury site about Se5. The disorder is such that the
relative occupancy of Cu3/Hg3 was satisfactorily refined as
2:1 (0.3333:0.16667). Copper centers (Cu1) are bonded to
two phosphine ligands and exhibit tetrahedral coordination,
and two other copper centers (Cu4, Cu5) are only singly
coordinated to a tripropylphosphine ligand and also assume
tetrahedral geometry. The internal copper centers (Cu2, Cu3)
exhibit coordination numbers 3 and 4, respectively. Cu‚‚‚
Se(3)-Hg(5)-Se(2) 101.69(8)
Se(4)-Hg(5)-Se(2) 105.29(8)
Hg(5)-Se(4)-Hg(3)
Cu(2)-Se(4)-Hg(3)
Cu(3)-Se(4)-Hg(3)A
Cu(2)-Se(1)-Hg(1)
86.19(8)
Cu(2)-Se(1)-Cu(4)A 83.24(12) Hg(4)-Se(4)-Cu(5)
Cu(2)-Se(1)-Cu(1)
60.54(8)
Hg(1)-Se(1)-Cu(1) 112.98(8)
Hg(3)A-Se(4)-Cu(5)
Hg(5)-Se(4)-Cu(3A)
100.0(3)
70.9(4)
49.5(3)
Cu(4)A-Se(1)-Cu(1) 134.02(13) Hg(4)-Se(4)-Cu(3A)
Cu(2)-Se(1)-Hg(4)A 58.58(8)
Cu(1)-Se(1)-Hg(4)A 117.01(8)
Cu(2)A-Se(2)-Hg(1) 85.61(8)
Hg(3)A-Se(4)-Cu(3A)
Hg(5)-Se(4)-Cu(3A)A
Cu(2)-Se(4)-Cu(3A)A 101.6(4)
36.8(4)
Cu(2)A-Se(2)-Cu(5) 84.95(12) Cu(5)-Se(4)-Cu(3)A
Hg(1)-Se(2)-Cu(5) 89.11(11) Hg(5)-Se(4)-Cu(4)
101.5(4)
98.34(11)
88.45(13)
100.3(4)
Hg(1)-Se(2)-Cu(1)A 110.87(8)
Cu(2)A-Se(2)-Hg(5) 60.81(7)
Hg(1)-Se(2)-Hg(5)
Cu(1)A-Se(2)-Hg(5) 120.03(8)
Hg(4)B-Se(3)-Hg(5) 93.70(10) Hg(3)-Se(5)-Hg(3)A
Hg(5)-Se(3)-Hg(2) 93.64(9)
Hg(5)-Se(3)-Cu(4)B 117.70(13) Hg(3)a-Se(5)-Cu(3A)
Cu(5)-Se(4)-Cu(4)
Cu(3A)-Se(4)-Cu(4)
78.18(5)
Cu(3A)A-Se(4)-Cu(4) 114.2(4)
Cu(3)A-Se(4)-Cu(4)
132.3(3)
60.065(17)
Hg(3)-Se(5)-Cu(3A)B 126.5(3)
53.5(3)
Hg(4)B-Se(3)-Cu(5) 116.82(12) Cu(3A)E-Se(5)-Cu(3A) 180.0(11)
Hg(2)-Se(3)-Cu(5) 109.11(12) Cu(3A)B-Se(5)-Cu(3A) 111.9(4)
Cu(4)B-Se(3)-Cu(5) 128.83(14) Hg(3)-Se(5)-Cu(3A)C
Hg(5)-Se(3)-Cu(3)B 68.4(3)
53.5(3)
a Symmetry transformations used to generate equivalent atoms: A, x -
y, x, -z; B, -y, x - y, z; C, -x + y, -x, z; D, y, -x + y, -z; E, -x, -y,
-z.
Cu and Hg‚‚‚Hg contacts are ∼2.5 and 3.4 Å, respectively,
which is consistent with oxidation states +1 (Cu) and +2
(Hg) for the d10 metals centers. The Hg atoms display either
near-linear coordination (Hg1; -Se1-Hg1-Se2 ) 179.41-
(7)°) or trigonal planar (Hg2, Hg3, Hg4, Hg5) geometry.
The selenium atoms bridge the copper and mercury centers
in µ3 (Se5) or µ4 (Se1, Se2, Se3, Se4) fashion. A total of 13
of the 25 Se2- ligands in 2 form a nonbonded centered
icosahedron (Se3-5 and their symmetry equivalents, Figure
3), the remaining selenium surrounding this central polyhe-
dron. The Hg-Se distances are comparable to the Hg-S
lengths in 1, 2.230(3) Å (Hg5-Se3)-3.018(2) Å (Hg5-
Se2). UV-vis analysis of 2 in the solid state displays a
featureless absorption spectrum, with an onset of absorption
at ∼800 nm.
All of our attempts at accessing a Hg-Cu-Te complex
using the tellurium reagent (Pr3P)3Cu-TeSiMe3 have been
unsuccessful to date, as invariably only amorphous, black
materials are produced. Surprisingly, the synthesis of ternary
clusters using triethylphosphine analogues of the copper
chalcogenolate reagents 4a,b have also been unsuccessful
to date in stabilizing HgCuS/Se complexes. Reaction condi-
tions analogous to those used for the synthesis of 1 and 2
using the shorter chain triethlylphosphine ligands repeatedly
lead to the formation of insoluble precipitates or the
Inorganic Chemistry, Vol. 41, No. 22, 2002 5695

Tran et al.
Figure 2. Molecular structure of [Hg15Cu20Se25(PPr3)18] (2). Carbon atoms
about the phosphorus centers have been omitted for clarity.
Figure 4. Molecular structure of [Cu6In8S13Cl4(PEt3)12] (3). Carbon atoms
about the phosphorus centers have been omitted for clarity.
The yield of 3 can be markedly improved (50%) however
by providing an additional source of sulfide ligands, in the
form of S(SiMe3)2, according to eq 2:
8InCl3 + 6(PEt3)3Cu-SSiMe3 (5) + 7S(SiMe3)2 f
[Cu6In8Cl4S13(PEt3)12] (3) + 20ClSiMe3 + 6PEt3 (2)
Small crystals of 3 were grown from pentane-THF
mixtures at -5 °C. Repeated attempts at growing larger
samples were unsuccessful, and thus, the diffraction data are
weak. In addition, crystals of 3 desolvate rapidly once
removed from their mother liquor. Both of these factors
contribute to the rather poor quality of the X-ray data;
however, the structure of 3 could be satisfactorily solved
and refined (Tables 2 and 3). The structure of this molecule
is markedly different from that observed in the copper-
indium-sulfur cluster,15a I. The structure of 3 (Figure 4) does
not display any adamantoid structural characteristics as
observed in [Cu6In3(SEt)16]-, which contains (surface) thio-
late ligands. Thus, while the Cu6In3 cluster is described as
having a central [Cu6S4] core, 3 has an inner [In8S13]
framework. The structure of 3 is very similar to that of two
recently reported copper-indium-selenide clusters [Cu6In8-
Se13Cl4(PPh3)6(CH8O)] and [Cu6In8Se13Cl4(PnPr2Ph)12] (II).6a
The [In8S13] core has a central sulfur atom, S13, that is
coordinated to four inner indium centers (In2, In4, In5, In7)
in a distorted tetrahedral geometry (-In-S13-In 108.4(3)-
111.0(3)°). These inner indium centers are each bonded to
three additional sulfur atoms, which themselves are also
bonded to the four outer (In1, In3, In6, In8) indium centers.
The two sets of inner and outer indium centers (In2, In4,
In5, In7 and In1, In3, In6, In8) are each arranged to form
In4 tetrahedra. The 12 outer sulfur centers (S1-S12) act as
µ3-ligands, each bonded to two indium centers and one Cu-
(PEt3)2 unit. The In-S bonds of the inner indium centers to
these sulfur ligands (Table 3) range from 2.394(9) to 2.454-
(9) Å in length. These bonds are observed to be slightly
shorter than the In-S12 bonds of the outer indium centers,
which range from 2.425(10) to 2.473(9) Å. The In-S
contacts to the central sulfur, S13, are even longer at 2.541-
(8)-2.559(8) Å. The outer S1-S12 centers are arranged such
that they form a distorted (nonbonded) icosahedral arrange-
Figure 3. Nonbonded Se25 polyhedron in 2.
decomposition of the reagent and subsequent formation of
elemental selenium or tellurium.
The recent report by Eichho¨fer and Fenske of CuInSe
clusters using a mixture of phosphine-solubilized CuCl:InCl3
salts and Se(SiMe3)2 prompted us to explore the suitability
of reagents (R3P)Cu-SSiMe3 for the synthesis of Cu-In-S
cluster complexes. The first copper-indium-sulfur (thiolate)
cluster was reported by Kanatzidis and co-workers,15a
[Cu6In3(SEt)16]- (I), in an attempt to use it as a precursor to
CuInS2. The same group was then successful in a subsequent
attempt, in making [(Ph3P)2CuIn(µ-E-Et)4] (E ) Se, S), the
first single-source precursor to CuInE2.15b
The reaction of a 3:1 ratio of 5:InCl3 leads to trace amounts
of [Cu6In8Cl4S13(PEt3)12] (3) as the only crystalline product.
(15) (a) Hirpo, W.; Dhingra, S.; Kanatzidis, M. G. J. Chem. Soc., Chem.
Commun. 1992, 557-558. (b) Hirpo, W.; Dhingra, S.; Sutorik, A. C.;
Kanatzidis, M. G. J. Am. Chem. Soc. 1993, 115, 1597-1599.
5696 Inorganic Chemistry, Vol. 41, No. 22, 2002

Ternary Nanoclusters of CuHgS, CuHgSe, and CuInS
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
[Cu6In8S13Cl4(PEt3)12] (3)
Table 3. Crystallographic Data for the Structure Determinations
of 1-3
In(1)-Cl(1)
In(1)-S(7)
In(1)-S(3)
In(1)-S(1)
In(2)-S(8)
In(2)-S(1)
In(2)-S(4)
In(2)-S(13)
In(3)-S(5)
In(3)-Cl(2)
In(3)-S(2)
In(3)-S(4)
In(4)-S(3)
In(4)-S(2)
In(4)-S(6)
In(4)-S(13)
In(5)-S(10)
In(5)-S(5)
In(5)-S(12)
In(5)-S(13)
In(6)-Cl(3)
In(6)-S(9)
In(6)-S(12)
2.403(9)
2.453(8)
2.455(8)
2.459(9)
2.394(9)
2.440(8)
2.454(8)
2.553(8)
2.425(10)
2.428(9)
2.433(8)
2.454(8)
2.402(8)
2.427(8)
2.439(8)
2.558(7)
2.416(9)
2.435(9)
2.454(9)
2.541(8)
2.403(11)
2.428(10)
2.443(9)
In(6)-S(6)
In(7)-S(9)
In(7)-S(7)
In(7)-S(11)
In(7)-S(13)
In(8)-Cl(4)
In(8)-S(10)
In(8)-S(8)
In(8)-S(11)
Cu(1)-S(1)
Cu(1)-S(2)
Cu(2)-S(5)
Cu(2)-S(6)
Cu(3)-S(9)
Cu(3)-S(3)
Cu(4)-S(7)
Cu(4)-S(8)
Cu(5)-S(4)
Cu(5)-S(10)
Cu(6)-S(12)
Cu(6)-S(11)
2.454(9)
2.430(9)
2.437(8)
2.452(9)
2.559(8)
2.426(11)
2.465(9)
2.473(9)
2.473(9)
2.368(9)
2.443(9)
2.407(10)
2.415(10)
2.410(9)
2.429(9)
2.341(9)
2.474(9)
2.402(9)
2.431(9)
2.355(10)
2.413(9)
param
1
2
3
chem formula
C
162H378Cu20-
Hg15P18 S25
7965.25
R3h
C
162H378Cu20- C72H180Cl4Cu6-
Hg15P18Se25 In8P12S13
3276.18
fw
9137.75
R3h
space group
temp (°C)
a (Å)
I4h2d
-73
-73
-73
23.5814(9)
43.376(2)
90
23.7830(6)
43.2493(9)
90
38.2199(7)
36.9701(7)
90
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
90
120
90
120
90
90
20 889.1(15)
10.044
3
21 185.7(9)
12.940
3
54 004.5(17)
2.714
µ (Mo KR1, mm-1
Z
)
16
1.612
Fc (g cm-3
)
1.900
2.149
data:params
2586:300
5769:314
R1 ) 0.0746
13 527:672
R1 ) 0.1118
R indices [I > 2σ(I)]a R1 ) 0.0709
wR2 ) 0.2167 wR2 ) 0.2094 wR2 ) 0.2831
2
2
2
a R1 ) Σ||Fo| - |Fc||/Σ|Fo|. wR2 ) {Σ[w(Fo - Fc )2/Σ[wFo ]2]1/2
.
ment. The four inner indium centers are positioned below
the triangular faces of the icosahedron, while the four
chlorine-bonded indium atoms lie above S3 faces of the
defined S12 polyhedron. The 12 surface PEt3 and 4 Cl ligands
stabilize the inner 1.0 × 1.0 × 1.0 nm3 core.
Cl(1)-In(1)-S(7)
Cl(1)-In(1)-S(3)
S(7)-In(1)-S(3)
Cl(1)-In(1)-S(1)
S(7)-In(1)-S(1)
S(3)-In(1)-S(1)
S(8)-In(2)-S(1)
S(8)-In(2)-S(4)
S(1)-In(2)-S(4)
S(8)-In(2)-S(13)
S(1)-In(2)-S(13)
S(4)-In(2)-S(13)
S(5)-In(3)-Cl(2)
S(5)-In(3)-S(2)
Cl(2)-In(3)-S(2)
S(5)-In(3)-S(4)
Cl(2)-In(3)-S(4)
S(2)-In(3)-S(4)
S(3)-In(4)-S(2)
S(7)-In(7)-S(11)
S(9)-In(7)-S(13)
S(7)-In(7)-S(13)
S(11)-In(7)-S(13)
Cl(4)-In(8)-S(10)
Cl(4)-In(8)-S(8)
S(10)-In(8)-S(8)
Cl(4)-In(8)-S(11)
S(10)-In(8)-S(11)
S(8)-In(8)-S(11)
S(1)-Cu(1)-S(2)
S(5)-Cu(2)-S(6)
S(9)-Cu(3)-S(3)
S(7)-Cu(4)-S(8)
S(4)-Cu(5)-S(10)
P(11)-Cu(6)-P(12)
S(12)-Cu(6)-S(11)
Cu(1)-S(1)-In(2)
Cu(1)-S(1)-In(1)
In(2)-S(1)-In(1)
In(4)-S(2)-In(3)
In(4)-S(2)-Cu(1)
In(3)-S(2)-Cu(1)
In(4)-S(3)-Cu(3)
In(4)-S(3)-In(1)
Cu(3)-S(3)-In(1)
Cu(5)-S(4)-In(3)
Cu(5)-S(4)-In(2)
In(3)-S(4)-In(2)
Cu(2)-S(5)-In(3)
102.9(3)
S(3)-In(4)-S(6)
S(2)-In(4)-S(6)
S(3)-In(4)-S(13)
S(2)-In(4)-S(13)
S(6)-In(4)-S(13)
S(10)-In(5)-S(5)
S(10)-In(5)-S(12)
S(5)-In(5)-S(12)
S(10)-In(5)-S(13)
S(5)-In(5)-S(13)
S(12)-In(5)-S(13)
Cl(3)-In(6)-S(9)
Cl(3)-In(6)-S(12)
S(9)-In(6)-S(12)
Cl(3)-In(6)-S(6)
S(9)-In(6)-S(6)
S(12)-In(6)-S(6)
S(9)-In(7)-S(7)
S(9)-In(7)-S(11)
Cu(2)-S(5)-In(5)
In(3)-S(5)-In(5)
Cu(2)-S(6)-In(4)
Cu(2)-S(6)-In(6)
In(4)-S(6)-In(6)
Cu(4)-S(7)-In(7)
Cu(4)-S(7)-In(1)
In(7)-S(7)-In(1)
In(2)-S(8)-In(8)
In(2)-S(8)-Cu(4)
In(8)-S(8)-Cu(4)
Cu(3)-S(9)-In(6)
Cu(3)-S(9)-In(7)
In(6)-S(9)-In(7)
In(5)-S(10)-Cu(5)
In(5)-S(10)-In(8)
Cu(5)-S(10)-In(8)
Cu(6)-S(11)-In(7)
Cu(6)-S(11)-In(8)
In(7)-S(11)-In(8)
Cu(6)-S(12)-In(6)
Cu(6)-S(12)-In(5)
In(6)-S(12)-In(5)
In(5)-S(13)-In(2)
In(5)-S(13)-In(4)
In(2)-S(13)-In(4)
In(5)-S(13)-In(7)
In(2)-S(13)-In(7)
In(4)-S(13)-In(7)
115.6(3)
116.2(3)
102.6(3)
101.7(3)
100.3(3)
116.8(3)
116.0(3)
116.9(3)
101.8(3)
100.5(3)
100.1(3)
106.8(4)
103.4(4)
112.5(3)
105.3(4)
112.2(3)
115.6(3)
115.8(3)
117.6(3)
108.8(4)
99.7(3)
105.1(3)
115.8(3)
107.5(3)
113.3(3)
111.3(3)
115.7(3)
118.2(3)
114.4(3)
103.1(3)
100.0(3)
101.4(3)
105.0(3)
114.4(3)
104.3(3)
113.3(3)
105.3(3)
113.3(3)
116.5(3)
115.5(3)
100.2(3)
101.0(3)
102.4(3)
106.0(4)
105.0(4)
112.7(3)
106.2(4)
112.2(3)
114.0(3)
104.3(3)
105.6(3)
105.8(3)
104.1(3)
105.2(3)
113.4(5)
105.2(3)
108.4(3)
116.6(3)
99.3(3)
The UV spectrum for a solution of 3 displays a weak
maximum at 400 nm, with the onset of absorption at 490
nm, mirroring observations for the related selenium complex
[Cu6In8Se13Cl4(PPh3)6(OC4H8)].6a Solid-state diffuse reflec-
tance spectra of 3 display a similar profile.
Conclusions
We have demonstrated that tris(trialkylphosphine)copper-
(I)-(trimethylsilyl)chalcogenolates (E ) S, Se)10 may be
used for the synthesis of ternary nanoclusters. The reaction
of 4a,b with mercury(II) acetate led to the isolation of the
pinwheel-shaped complexes [Hg15Cu20E25(PnPr3)18] (E ) S,
Se) (1 and 2), respectively. The cluster [Cu6In8S13Cl4(PEt3)12]
(3) can be similarly prepared from the reaction of 5 and InCl3
although the yields are improved dramatically if additional
amounts of S(SiMe3)2 are used.
108.4(3)
110.5(4)
99.8(3)
110.9(3)
112.6(3)
99.1(3)
Experimental Section
98.8(3)
Experiments were all performed in an inert nitrogen atmosphere
with the use of Schlenk line techniques and gloveboxes. Complexes
4 and 5 were synthesized as described.10 PPr3 and S(SiMe3)2
109.5(4)
110.9(3)
113.3(4)
109.0(3)
99.1(3)
107.3(4)
100.2(3)
113.8(3)
107.1(3)
113.3(3)
98.4(3)
114.1(4)
110.2(4)
98.9(3)
108.4(3)
111.0(3)
109.4(3)
108.8(3)
109.0(3)
110.2(3)
16
17
were prepared and purified as reported in the literature. Hg(OAc)2
and InCl3 were purchased from Strem Chemical at 99.99% purity
and used as supplied. Solvents were obtained from Caledon and
BDH Chemicals and subsequently dried and distilled over sodium/
benzophenone (Et2O, THF) or P2O5 (CH3CN). Nuclear magnetic
resonance spectroscopy experiments were measured on Gemini 300
(1H, 300.075 MHz; 13C{1H}, 75.4 MHz) and Varian Mercury 400
(1H, 400.088 MHz; 13C{1H}, 100.613 MHz; 31P{1H}, 161.957 MHz)
spectrometers. 1H and 13C{1H} NMR spectra were measured using
standard settings and chemical shifts were reported in ppm and
externally referenced to SiMe4 (using the residual protons and the
99.1(3)
109.3(3)
109.4(3)
108.6(3)
98.9(3)
109.0(3)
110.9(3)
108.2(3)
99.2(3)
(16) Cumper, C. W. N.; Foxton, A. A.; Read, J.; Vogel, A. I. J. Chem.
Soc. 1964, 430.
(17) (a) Schmidt, V. H.; Ruf, H. Z. Anorg. Allg. Chem. 1963, 321, 270.
(b) So, J.; Boudjouk, P. Synthesis 1989, 306.
111.9(4)
Inorganic Chemistry, Vol. 41, No. 22, 2002 5697

Tran et al.
carbons of the deuterated solvent, respectively). 31P{1H} spectra
were referenced externally to 85% phosphoric acid with the 90°
pulse width at 16 µs, using a 16 µs pulse, a 0.4 s acquire time, and
a 1 s delay time. Chemisar Laboratories Inc. (Guelph, Ontario,
Canada) performed chemical analyses. GC-MS analysis was
performed on a Finnigan MAT 8200 mss-data system. Gas
chromatography was performed with an injector temperature of 225
°C and a 30 m DB5 MS column. The UV-vis spectra were obtained
on a Varian Cary 100 Bio UV-vis spectrophotometer. An
additional module was used to measure solid-phase diffuse reflec-
tance spectra, and spectra were collected as the percent reflectance
of a sample diluted in dried KBr. Thermogravometric analysis
(TGA) was performed on a Mettler Toledo TGA SDTA851e with
included software and a constant nitrogen purge. The volatiles were
collected through vinyl tubing into a Schlenk tube immersed in a
cold trap of liquid nitrogen.
Synthesis of [Hg15Cu20S25(PPr3)18] (1). Mercury(II) acetate (0.63
g, 2.0 mmol) was dissolved in 15 mL of cold (∼-30 °C)
tetrahydrofuran with tripropylphosphine (0.64 mL, 4.0 mmol) to
give a clear colorless solution. The mercury acetate solution was
cooled to -75 °C and added to a solution of 4a (2.66 g, 4.0 mmol)
in 10 mL of THF at -75 °C. The reaction mixture turned bright
yellow in color and became bright orange upon warming to -30
°C. Orange crystalline blocks of 1, suitable for X-ray analysis (0.62
g, 60% based on Hg), appeared within ∼48 h at -30 °C. Anal.
Calcd: C, 24.43; H, 4.78. Found: C, 24.43; H, 4.57.
during data collection. Single crystals of 1-3 suitable for X-ray
analysis were mounted on glass fibers. Data were collected using
a Nonius Kappa-CCD diffractometer running the COLLECT
(Nonius, 1998) software. Unit cell parameters were calculated and
refined from the full data set. Crystal cell refinement and data
reduction were carried out with the Nonius DENZO package. The
data were scaled using SCALE-PACK (Nonius, 1998), and no other
absorption corrections were applied. The SHELXTL (G. M.
Sheldrick, Madison, WI) program package was applied to solve
(direct methods) and refine the structure. All metal and phosphorus
atoms (with the exception of the disordered P and C atoms) were
refined with anisotropic thermal parameters, and carbon atoms were
refined isotropically. A summary of the X-ray crystallographic data
can be found in Table 3. Crystals of 3 appeared to desolvate rapidly,
and this, in conjunction with the small sample size of the crystal
(0.001 mm3), subsequently affected the quality of the X-ray data.
Although the structure of 3 was successfully solved in the
noncentrosymmetric space group I42d, highly disordered ethyl
ligands about the phosphorus centers prohibited the location of all
C atoms to be determined in the difference Fourier map. Two data
sets were collected for 3, and the better of the two was used for
the solution and refinement of 3. The absolute structure parameter
(0.51(5)) was refined using the SHELX “TWIN” command.
Attempts to solve the structure in centrosymmetrical space groups
(I4/m, I4/mmm) were unsuccessful. Figures of 1-3 were generated
using the SCHAKAL 99 drawing program.18
Synthesis of [Hg15Cu20Se25(PPr3)18] (2). [Hg15Cu20Se25(PnPr3)18]-
(2) was prepared in a similar procedure as used for 1: Hg(OAc)2
(0.77 g, 2.4 mmol) was dissolved in 20 mL of THF with PPr3 (0.96
mL, 4.8 mmol). Once completely dissolved, this clear solution was
cooled to -75 °C and added to a cold solution of 4b dissolved in
40 mL of THF at the same temperature. Upon mixing, the reaction
mixture immediately became clear, bright orange and was warmed
slowly to -30 °C. Within ∼48 h, ruby red crystals of 2, suitable
for X-ray analysis, formed from a pale orange solution. Yield: 1.23
g (84% based on Hg).
Powder X-ray Diffraction Analysis. Powder XRD measure-
ments were done on an Inel diffractometer equipped with XRG
3000 generator and CPS 120 curved position sensitive detector using
monochromated Cu KR1 radiation (λ ) 1.540 56 Å), as thin films.
The accompanying software was used for peak searches and
indexing.
Acknowledgment. We are grateful to the Natural Sci-
ences and Engineering Research Council of Canada and the
Government of Ontario’s Premier’s Research Excellence
Award program (to J.F.C.) for supporting this research. We
also acknowledge the Canada Foundation for Innovation, the
Ontario Research and Development Challenge Fund, and The
University of Western Ontario’s ADF program for equipment
funding.
Anal. Calcd: C, 21.29; H, 4.17; P, 6.10. Found: C, 22.70; H,
4.54; P, 6.41.
Preparation of [Cu6In8S13Cl4(PEt3)12] (3). InCl3 (0.07 g, 0.3
mmol) was dissolved in 10 mL of tetrahydrofuran, resulting in a
clear, colorless solution. After the InCl3 solution was cooled to -65
°C, it was added to a cold (-65 °C) solution of (PEt3)3CuSSiMe3
(5) (0.12 g, 0.225 mmol) in 5 mL of tetrahydrofuran. S(SiMe3)2
(0.06 mL, 0.263 mmol) was then added, and the reaction solution
was allowed to warm to -25 °C for 12 h. White powder
precipitated, and the solution became slightly colored overnight.
After several hours at room temperature, the precipitate redissolved
and the solution became yellow in color. X-ray-quality, pale yellow
crystals of 3 formed by layering solutions with pentane (5:2 C5H12-
OC4H8) and cooling to -5 °C. Yield: 0.06 g (50%).
Supporting Information Available: X-ray crystallographic files
in CIF format for clusters [Hg15Cu20S25(PPr3)18] (1), [Hg15Cu20-
Se25(PPr3)18] (2), and [Cu6In8S13Cl4(PEt3)12] (3), a powder diffrac-
tion pattern for the residue of 1 after thermal treatment to 110 °C
(Figure S1), a powder diffraction pattern for the residue of 1 after
thermal treatment to 900 °C (Figure S2), and a projection of the
disorder of the central core in 2 (Figure S3). This material is
available free of charge via the Internet at http://pubs.acs.org.
1H NMR (CD3CN, δ): 1.6 [br, 2H, CH2], 1.1 [d of t, 3JHH ) 7.2
Hz, 3JHP ) 14.6 Hz, 3H, CH3]. 31P{1H} NMR (CD3CN, δ): -13.0
[s, br]. Anal. Calcd: C, 26.40; H, 5.54. Found: C, 25.9; H, 5.48.
X-ray Crystallographic Analysis of 1-3. Crystals were mounted
immersed in cold mineral oil and placed in a cold stream of N2
IC0110528
(18) Keller, E. SCHAKAL 1999, A Computer Program for the Graphic
Representation of Molecular and Crystallographic Models; Universita¨t
Freiburg: Freiburg, Germany, 1999.
5698 Inorganic Chemistry, Vol. 41, No. 22, 2002