π-coordination of silver and copper to mercury bis-alkynyls: Synthesis and structural characterization

Article abstract of DOI:10.1021/om000564b

The reactions between the mercury-dialkynyl complexes [Hg(C≡CR)₂] (R = C₆H₅, -C₆H₄-CH₃-4, and -C(CH₃)₃) and a series of Ag(I) and Cu(I) compounds are reported. Compounds with the general formula [Hg(C≡CR)₂Cu₂(CH₃CN)₄][PF ₆]₂, [Hg(C≡CR)₂M₂(L)₂]X₂ (M = Ag, Cu; R = C₆H₅, -C₆H₄-CH₃-4, and -C(CH₃)₃; L = 2,2′-bipyridine, 1,10-phenanthroline; X = PF₆ or BF₄), and {[Hg(C≡CR)₂Ag][BF₄]}_n (R = C₆H₅ and -C₆H₄-CH₃-4) resulted from these reactions. In these complexes the silver and copper atoms are π-coordinated to the alkynyls' triple bonds.

Full text of DOI:10.1021/om000564b

Organometallics 2000, 19, 5209-5217
5209
π-Coor d in a tion of Silver a n d Cop p er to Mer cu r y
Bis-a lk yn yls: Syn th esis a n d Str u ctu r a l Ch a r a cter iza tion
Daniela Rais, D. Michael P. Mingos, Ramo´n Vilar,* Andrew J . P. White, and
David J . Williams
Department of Chemistry, Imperial College of Science, Technology and Medicine,
South Kensington, London SW7 2AY, U.K.
Received J une 30, 2000
The reactions between the mercury-dialkynyl complexes [Hg(CtCR)2] (R ) C6H5, -C6H4-
CH3-4, and -C(CH3)3) and a series of Ag(I) and Cu(I) compounds are reported. Compounds
with the general formula [Hg(CtCR)2Cu2(CH3CN)4][PF6]2, [Hg(CtCR)2M2(L)2]X2 (M ) Ag,
Cu; R ) C6H5, -C6H4-CH3-4, and -C(CH3)3; L ) 2,2′-bipyridine, 1,10-phenanthroline; X )
PF6 or BF4), and {[Hg(CtCR)2Ag][BF4]}n (R ) C6H5 and -C6H4-CH3-4) resulted from these
reactions. In these complexes the silver and copper atoms are π-coordinated to the alkynyls’
triple bonds. Crystal structures of three of these complexes have been obtained, confirming
the formulation and in two instances revealing weak anion‚‚‚cation interactions. The
structure of {[Hg(CtCTol)2Ag][BF4]}n has been shown to be a polymer comprised of helices
cross-linked by C-H‚‚‚π interactions.
In tr od u ction
yls, for which relatively few studies have been previ-
ously reported.7 The linear coordination exhibited by the
mercury(II) ion in organometallic complexes together
with the evidence of weak Hg(II)‚‚‚Hg(II) interactions8
similar to the aurophilicity exhibited by gold suggests
that mercury dialkynyls could be valuable building
blocks for the synthesis of metal-organic polymers and
supramolecular aggregates.
The study of polynuclear metal-organic complexes
has increased rapidly in recent years.1 The interest in
these mixed-metal systems stems not only from their
structural variety but also from the possibility of form-
ing extensively delocalized arrangements which could
lead to metal-organic polymers exhibiting metal-metal
communication.2 Alkynyl groups are among the most
widely used ligands for this purpose.
Metal-alkynyls are well known for most metals, and
their chemistry has been developed extensively.3 Partly
this has been due to their application as reagents in
organometallic transformations4 and for the synthesis
of polymetallic assemblies.5 The chemistry of mercury-
alkynyl compounds, however, has not been so thor-
oughly studied, even though they were first reported
several decades ago.6 One class of compounds that
deserve particular attention are the mercury-dialkyn-
As part of our studies on mercury-alkynyl com-
pounds, we were interested in exploring the possibility
of coordinating metals in an η2 fashion to the triple
bonds of the mercury alkynyls. Extensive work by
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* Corresponding author. Tel: +44-20-7594-5755. Fax: +44-20-
7594-5804. E-mail: r.vilar@ic.ac.uk.
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10.1021/om000564b CCC: $19.00 © 2000 American Chemical Society
Publication on Web 11/03/2000

5210 Organometallics, Vol. 19, No. 24, 2000
Rais et al.
Fornies,9 Lang,10 Yam,11 and others12 has demonstrated
that metals such as copper, silver, and gold can π-co-
ordinate to alkynyl groups of organometallic compounds
in an η2 fashion, giving rise to interesting polymetallic
species. Inspired by this chemistry and because of our
interest in the supramolecular interactions of organo-
metallic species, the reactions of [Hg(CtCR)2] (R )
-C6H5, -C6H4-CH3-4, -C(CH3)3) with silver and cop-
per compounds were studied. Here we report the
synthesis and characterization of [Hg(CtCR)2Cu2(CH3-
CN)4][PF6]2 (R ) C6H5, -C6H4-CH3-4, -C(CH3)3), [Hg-
(CtCR)2M2(L)2]X2 (R ) C6H5, -C6H4-CH3-4, -C(CH3)3;
Sch em e 1. Syn th esis of 1-5
-
M ) Ag, Cu; L ) bipyridine, phenanthroline; X ) PF6
or BF4-), and the polymeric compounds {[Hg(CtCR)2Ag]-
[BF4]}n (R ) C6H5, -C6H4-CH3-4). The X-ray crystal
structures of three of these species are presented.
Resu lts a n d Discu ssion
Syn th esis of [Hg(CtCR)2Cu 2(CH3CN)4][P F6]2 an d
{[Hg(CtCR)2Ag][BF 4]}n . When the mercury-dialkyn-
yl compounds [Hg(CtCR)2] (R ) C6H5, -C6H4-CH3-4,
-C(CH3)3) are reacted with 2 equiv of [Cu(CH3CN)4]-
[PF6] in organic solvents, white precipitates are formed.
1
On the basis of IR, H NMR, and elemental analyses
the new products obtained can be formulated as [Hg-
(CtCR)2Cu2(CH3CN)4][PF6]2 (R ) C6H5, 1; -C6H4-
CH3-4, 2; -C(CH3)3, 3) (see Scheme 1). This formulation
is also consistent with the mass spectrometric results.
Compared with the corresponding starting materials,
the IR spectra of these compounds show a shift of the
ν(CtC) stretch toward lower frequencies (see Table 1),
suggesting a π-bonding mode of copper to the alkynyl
ligands. Two bands in the region around 2320 and 2290
cm-1 are consistent with the presence of coordinated
Ta ble 1. ν(CtC) Str etch es (cm -1) for Com p ou n d s
1-17 a n d for th e Cor r esp on d in g Sta r tin g
Ma ter ia ls [Hg(CtCR)2]
compound
IR (cm-1) ν(CtC)
1
acetonitrile. The H NMR spectra of 1-3 show only one
[Hg(CtCPh)2]a
2146, 2113
2140
2175, 2142
2022, 1981
1981
set of signals for the R groups on the alkynyl ligand. In
all three cases these signals are shifted slightly com-
pared with those of the parent compounds. This formu-
lation has been confirmed by a single-crystal X-ray
analysis of compound 1.
[Hg(CtCTol)2]a
[Hg(CtCtBu)2]a
[Hg(CtCPh)2Cu2(CH3CN)4][PF6]2 (1)
[Hg(CtCTol)2Cu2(CH3CN)4][PF6]2 (2)
[Hg(CtCtBu)2Cu2(CH3CN)4][PF6]2 (3)
[Hg(CtCPh)2Cu2(bipy)2][PF6]2 (6)
[Hg(CtCTol)2Cu2(bipy)2][PF6]2 (7)
[Hg(CtCtBu)2Cu2(bipy)2][PF6]2 (8)
[Hg(CtCPh)2Cu2(phen)2][PF6]2 (9)
[Hg(CtCTol)2Cu2(phen)2][PF6]2 (10)
[Hg(CtCtBu)2Cu2(phen)2][PF6]2 (11)
{[Hg(CtCPh)2Ag][BF4]}n (4)
2011
1967, 1951
1968, 1941
1947
1983, 1963
1958, 1937
1964
Since both silver(I) and copper(I) show a similar
tendency to π-coordinate to alkenes and alkynes, the
(9) (a) Espinet, P.; Fornies, J .; Martinez, F.; Tomas, M.; Lalinde,
E.; Moreno, M. T.; Ruiz, A. J . Chem. Soc., Dalton Trans. 1990, 791.
(b) Fornies, J .; Lalinde, E.; Martin, A.; Moreno, M. T. J . Organomet.
Chem. 1995, 490, 179. (c) Fornies, J .; Lalinde, E. J . Chem. Soc., Dalton
Trans. 1996, 2587 (d) Charmant, J . P. H.; Fornies, J .; Gomez, J .;
Lalinde, E.; Merino, R.; Moreno, M. T.; Orpen, A. G. Organometallics
1999, 18, 3353.
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113. (b) Lang, H.; Weinmann, M. Synlett 1996, 1. (c) J anssen, M. D.;
Herres, M.; Zsolnai, L.; Spek, A. L.; Grove, D. M.; Lang, H.; van Koten,
G. Inorg. Chem. 1996, 35, 2476. (d) J anssen, D. M.; Ko¨hler, K.; Herres,
M.; Dedieu, A.; Smeets, W. J . J .; Spek, A. L.; Grove, D. M.; Lang, H.;
van Koten, G. J . Am. Chem. Soc. 1996, 118, 4817. (e) Lang, H.; Ko¨hler,
K.; Zsolnai, L. J . Chem. Soc., Chem. Commun. 1996, 2043. (f) Lang,
H.; Ko¨hler, K.; Rheinwald, G.; Zsolnai, L.; Bu¨chner, M.; Driess, A.;
Huttner, G.; Stra¨hle, J . Organometallics 1999, 18, 598. (g) Back, S.;
Lang, H. Organometallics 2000, 19, 749.
(11) (a) Yam, V. W.-W.; Chong, S. H.-F.; Wong, K. M.-C.; Cheung,
K.-K. J . Chem. Soc., Chem. Commun. 1999, 1013. (b) Yam, V. W.-W.;
Yu, K.-L.; Cheung, K.-K. J . Chem. Soc., Dalton Trans. 1999, 2913.
(12) (a) Yamazaki, S.; Deeming, A. J .; Speel, D. M.; Hibbs, D. E.;
Hursthouse, M. B.; Malik, K. M. A. J . Chem. Soc., Chem. Commun.
1997, 177. (b) Schulte, P.; Behrens, U. J . Chem. Soc., Chem. Commun.
1998, 1633. (c) Tanaka, S.; Yoshida, T.; Adachi, T.; Yoshida, T.;
Onitsuka, K.; Sonogashira, K. Chem. Lett. 1994, 877. (d) Yamazaki,
S.; Deeming, A. J . J . Chem. Soc., Dalton Trans. 1993, 3051. (e) Mingos,
D. M. P.; Yau, J .; Menzer, S.; Williams, D. J . Angew. Chem., Int. Ed.
Engl. 1995, 34, 1894.
2094
{[Hg(CtCTol)2Ag][BF4]}n (5)
2090
[Hg(CtCPh)2Ag2(bipy)2][BF4]2 (12)
[Hg(CtCTol)2Ag2(bipy)2][BF4]2 (13)
[Hg(CtCtBu)2Ag2(bipy)2][BF4]2 (14)
[Hg(CtCPh)2Ag2(phen)2][BF4]2 (15)
[Hg(CtCTol)2Ag2(phen)2][BF4]2 (16)
[Hg(CtCtBu)2Ag2(phen)2][BF4]2 (17)
2049, 1995
2063, 1997
2053
2058
2051, 2038
2049
a
Starting materials for the synthesis of species 1-17.
analogous reactions with silver have been studied. In
contrast with the reactions with copper, when the
mercury bis-alkynyl complexes [Hg(CtCR)2] (R ) C6H5,
-C6H4-CH3-4) are reacted with [Ag(CH3CN)4][BF4], the
expected [Hg(CtCR)2Ag2(CH3CN)4][BF4]2 compounds
are not formed. Instead, on the basis of elemental
analyses and IR and NMR spectroscopy, the white solids
obtained can be formulated as {[Hg(CtCR)2Ag][BF4]}n
(R ) C6H5, 4; -C6H4-CH3-4, 5) in which all the
acetonitrile ligands have been replaced. This formula-
tion is consistent with either a molecular square or a

π-Coordination of Ag and Cu to Hg Bis-alkynyls
Organometallics, Vol. 19, No. 24, 2000 5211
Sch em e 2
Stronger ligands would seem to be needed to displace
these coordinated solvent molecules (see next section).
Syn t h esis of [H g(CtCR )2M2(b ip y)2][P F 6]2 a n d
[Hg(CtCR)2M2(p h en )2][P F 6]2 (M ) Ag or Cu ; R )
C6H5, -C6H4-CH3-4, -C(CH3)3). After the unsuccess-
ful attempts to substitute the acetonitrile molecules
from compounds 1-3, reactions between these com-
plexes and the strongly chelating ligands 2,2′-bipyridine
and 1,10-phenanthroline have been investigated. When
2 equiv of 2,2′-bipyridine are added to solutions of [Hg-
(CtCR)2Cu2(CH3CN)4][PF6]2 in CH2Cl2, pale yellow
precipitates are obtained which can be formulated as
[Hg(CtCR)2Cu2(bipy)2][PF6]2 (R ) C6H5, 6; -C6H4-
CH3-4, 7; -C(CH3)3, 8) on the basis of elemental
1
analyses, FAB-mass spectrometry, and H NMR and IR
spectroscopy.
The IR spectra of compounds 6-8 show two ν(CtC)
bands which are shifted to lower frequencies compared
with those of the corresponding starting materials (see
Table 1). Strong bands in the region around 1600 cm-1
are attributed to the CdN stretching of the bipyridine
molecules. No ν(CtN) absorptions are observed in any
of the spectra of the three products, indicating that
substitution of the acetonitrile molecules has occurred.
Additionally, the signals in the 1H NMR spectra are
compatible with the presence of coordinated bipyridine.
The presence of only one set of signals indicates the
equivalence of the protons on the two rings of the
bipyridine, suggesting that free rotation around the Cu-
η2-alkynyl bond occurs in solution. The compounds are
insoluble in chlorinated solvents and THF. They are
slightly soluble in acetone, but they quickly decompose
(even under a N2 atmosphere) to a blue solution,
suggesting the presence of Cu(II) species. Thus, NMR
spectra in acetone must be run quickly on freshly made
solutions and, even then, good integration of the signals
is always hard to achieve (this is possibly due to the
presence of small amounts of paramagnetic Cu(II)
species). The instability of these compounds has pre-
vented us from undertaking further 13C and 199Hg NMR
spectroscopic studies in solution.
polymeric arrangement (see Scheme 2). The structure
of compound 5 has been established by a single-crystal
X-ray analysis, demonstrating to be the polymeric
arrangement (vide infra).
The IR spectra of compounds 4 and 5 show a shift of
the ν(CtC) stretches to lower frequencies (see Table 1)
compared with those of the parent mercury bis-alkynyl
complexes, thus suggesting a π-coordination of the silver
ions to the triple bonds of the alkynyl groups. These
spectra also indicate that all the acetonitrile ligands
have been substituted since no bands are observed in
the region between 2320 and 2290 cm-1. The molecular
peak in the FAB-mass spectrum has been assigned to
1
the [Hg(CtCR)2Ag]+ fragment. The H NMR spectra of
the three complexes show a small change in the chemi-
cal shifts of the R groups on the alkynyl ligands,
suggesting a new chemical environment around the bis-
alkynyl moieties. Interestingly, the reactions between
[Hg(CtCR)2] and the simple silver salt AgBF4 yield the
same compounds as those obtained with [Ag(CH3CN)4]-
[BF4], confirming that the acetonitrile is not retained
in the coordination sphere of the silver ion.
In an analogous series of reactions, compounds 1-3
have been reacted with 1,10-phenanthroline to yield the
new species [Hg(CtCR)2Cu2(phen)2][PF6]2 (R ) C6H5,
9; -C6H4-CH3-4, 10; -C(CH3)3, 11) as pale yellow
solids. The IR spectra of these compounds also show two
ν(CtC) absorptions shifted to lower frequencies than
those of the corresponding starting materials (see Table
1). The ν(CtN) bands for coordinated acetonitrile
molecules are not observed. Compounds 9-11 are
insoluble in most common solvents but slightly soluble
The different reactivities of [Hg(CtCR)2] with [Cu-
(CH3CN)4][PF6] and [Ag(CH3CN)4][BF4] are somewhat
unexpected. The larger shift of the ν(CtC) bond stretch
to lower frequencies in the copper derivatives compared
to those of the silver complexes suggests a stronger
coordination of the copper ion to the alkynyl bonds. The
presence of the coordinated acetonitrile molecules on the
copper centers in 1-3 is surprising compared with the
silver derivatives, where all the solvent molecules have
been replaced, especially since there is evidence in the
literature that the four acetonitrile groups in [Cu(CH3-
CN)4][PF6] can be displaced by coordination to two
metal-alkynyl groups (see for example the platinum-
alkynyl-copper compounds reported by Yam11b).
Several attempts to synthesize the copper analogues
of the polymeric species 4 and 5 have been made but
without success. This lack of success suggests that the
two remaining acetonitrile molecules are probably too
strongly coordinated to the copper center to be replaced
by the relatively weakly coordinating alkynyl ligand.
1
in acetone, allowing for their study in solution. The H
NMR spectra in acetone show signals due to the R
groups on the alkynyls and to the coordinated phenan-
throline. These compounds behave similarly to the
bipyridine complexes 6-8 and also decompose quickly
in solution.
The analogous silver compounds are obtained by
reacting the mercury-dialkynyl species [Hg(CtCR)2]
with silver(I) salts in the presence of bipyridine or
phenanthroline.
Reaction of the mercury bis-alkynyl compounds with
2 equiv of AgBF4 and 2 equiv of 2,2’-bipyridine in THF
produces [Hg(CtCR)2Ag2(bipy)2][BF4]2 (R ) C6H5, 12;

5212 Organometallics, Vol. 19, No. 24, 2000
Rais et al.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 5
Hg-C(1)
Ag-C(1)
Ag-C(11′)
C(1)-C(2)
2.00(2)
2.29(2)
2.27(2)
1.22(3)
Hg-C(11)
Ag-C(2)
Ag-C(12′)
C(2)-C(8)
2.02(2)
2.42(2)
2.43(2)
1.44(3)
C(1)-Hg-C(11)
C(1)-Ag-C(11′)
C(11′)-Ag-C(12′)
C(2)-Ag-C(12′)
Hg-C(1)-C(2)
Ag-C(2)-C(1)
C(1)-C(2)-C(8)
177.9(10)
172.2(8)
29.9(7)
125.6(6)
173(2)
C(1)-Ag-C(2)
C(2)-Ag-C(11′)
C(1)-Ag-C(12′)
Hg-C(1)-Ag
29.9(7)
153.8(7)
148.5(6)
106.2(8)
81.0(13)
114.7(13)
Ag-C(1)-C(2)
Ag-C(2)-C(8)
69.2(12)
174(2)
F igu r e 1. Molecular structure of 1, showing also the
weakly coordinated water molecules (50% probability el-
lipsoids).
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 12
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 1
Hg-C(1)
Ag-C(1)
Ag-N(1)
C(1)-C(2)
2.017(7)
2.235(7)
2.252(6)
1.209(11)
Hg-C(1′)
Ag-C(2)
Ag-N(2)
C(2)-C(8)
2.017(7)
2.351(7)
2.306(7)
1.465(8)
Hg-C(1)
Cu-C(1)
Cu-N(9)
Cu-O
2.006(8)
1.991(8)
1.938(7)
2.70(2)
Hg-C(1′)
Cu-C(2)
Cu-N(12)
C(1)-C(2)
2.006(8)
2.037(8)
1.967(8)
1.246(11)
C(1)-Hg-C(1′)
C(1)-Ag-N(1)
C(2)-Ag-N(1)
N(1)-Ag-N(2)
Ag-C(1)-C(2)
Ag-C(2)-C(1)
C(1)-C(2)-C(8)
180.0
C(1)-Ag-C(2)
C(1)-Ag-N(2)
C(2)-Ag-N(2)
Hg-C(1)-C(2)
Hg-C(1)-Ag
Ag-C(2)-C(8)
30.4(3)
121.9(2)
152.3(2)
167.8(7)
112.1(4)
125.3(4)
C(2)-C(8)
1.436(8)
164.0(3)
134.7(2)
72.7(2)
80.1(5)
69.5(5)
165.0(7)
C(1)-Hg-C(1′)
C(1)-Cu-N(9)
C(2)-Cu-N(9)
N(9)-Cu-N(12)
C(2)-Cu-O
N(12)-Cu-O
C(2)-C(1)-Hg
C(1)-C(2)-C(8)
C(8)-C(2)-Cu
180.0
151.7(3)
115.8(3)
102.0(3)
99.8(4)
C(1)-Cu-C(2)
C(1)-Cu-N(12)
C(2)-Cu-N(12)
C(1)-Cu-O
36.0(3)
105.7(3)
141.6(3)
100.5(4)
85.5(4)
74.0(5)
120.3(4)
70.0(5)
N(9)-Cu-O
89.3(4)
C(2)-C(1)-Cu
Cu-C(1)-Hg
C(1)-C(2)-Cu
Ta ble 5. Selected 13C{1H} NMR Ch em ica l Sh ifts
(p p m ) for Com p ou n d s 1-5, 14, a n d for th e
Cor r esp on d in g Sta r tin g Ma ter ia ls [Hg(CtCR)2]
165.7(7)
158.3(7)
131.7(4)
13C{1H} NMR (ppm)
compound
δ(CtC)
p-C6H4Me, 13; -C(CH3)3, 14) as white precipitates. The
compounds have been characterized on the basis of
elemental analyses, mass spectrometry, IR and NMR
spectroscopy, and, in the case of the phenyl derivative,
an X-ray single-crystal structural determination (vide
infra). The IR spectra show a shift of the CtC stretching
mode to lower frequencies, which is indicative of a
[Hg(CtCPh)2]a
Câ: 107.0; CR: 121.0
Câ: 104.1; CR: 120.5
Câ: 116.3; CR: 108.3
Câ: 108.4; CR: 115.6
Câ: 108.4; CR: 114.8
Câ: 104.8; CR: 90.4
Câ: 107.7; CR: 110.9
Câ: 108.6; CR: 108.8
Câ: 121.7; CR: 94.6
[Hg(CtCTol)2]a
[Hg(CtCtBu)2]a
[Hg(CtCPh)2Cu2(CH3CN)4][PF6]2 (1)
[Hg(CtCTol)2Cu2(CH3CN)4][PF6]2 (2)
[Hg(CtCtBu)2Cu2(CH3CN)4][PF6]2 (3)
{[Hg(CtCPh)2Ag][BF4]}n (4)
{[Hg(CtCTol)2Ag][BF4]}n (5)
{[Hg(CtCtBu)2Ag2(bipy)2][BF4]2 (8)
1
π-coordination of silver to the triple bond. The H NMR
spectra in acetone show the signals of the alkynyl
groups and the coordinated bipyridine in the expected
ratio. Further studies in solution have been prevented
by the insolubility of these compounds.
a
Starting materials for the synthesis of species 1-17.
of 1.246(11) Å is noticeably longer then those observed
in other mercury dialkynyls;13 this elongation is prob-
ably a consequence of the π-bonding, though in a
platinum dialkynyl complex with a “side-bonding” of a
mercury to the ethynyl bond the CtC distances were
still less than 1.2 Å.14 The partial occupancy included
water molecules located in an apical position with
respect to the trigonal copper coordination planes. The
Cu‚‚‚O distance [2.70(2) Å] is consistent with a weak,
out of plane, Cu-OH2 linkage.
The molecules pack to form parallel sheets, though
with only marginal π-π overlap. Although the mean
interplanar separations between symmetry-related aryl
rings are 3.29 Å, only the edges of the ring systems
overlap each other, the ring centroid‚‚‚ring centroid
separations being 4.42 Å. There are no close inter-
molecular contacts to the mercury centers, the shortest
F‚‚‚Hg distance being 3.24 Å, and the shortest Hg‚‚‚Hg
and Hg‚‚‚Cu nonbonded contacts are 8.48 and 3.47 Å,
respectively.
Analogous reactions between mercury-dialkynyls,
AgBF4, and phenanthroline yield the expected [Hg-
(CtCR)2Ag2(phen)2][BF4]2 (R ) C6H5, 15; p-C6H4Me, 16;
-C(CH3)3, 17) compounds in good yields. They have
been characterized on the basis of elemental analyses,
mass spectrometry, and IR and NMR spectroscopy.
X-r a y Cr ysta llogr a p h y of Com p ou n d s 1, 5, a n d
12. The X-ray analysis of [Hg(CtCPh)2Cu2(CH3CN)4]-
[PF6]2 (1) reveals the molecule to be on a crystal-
lographic inversion center and an almost planar geom-
etry for the cation (Figure 1); the mean deviation from
planarity for all the atoms excluding the included water
molecules and the anions is 0.056 Å.
The geometry at copper is essentially trigonal planar,
the metal being covalently bonded to two acetonitrile
ligands and π-bonded to the ethyne bond of the mercury
dialkynyl unit. The Cu-C(1) and Cu-C(2) distances are
slightly asymmetric at 1.991(8) and 2.037(8) Å, respec-
tively (Table 2). Accompanying this side-bonding are
distinct nonlinearities in the angles at C(1) [165.7(7)°]
and C(2) [158.3(7)°], the bending being away from the
copper center. There is also a small (ca. 6°) torsional
twist about the C(2)-C(8) bond. The Hg-C(1) distance
of 2.006(8) Å is unexceptional, but the CtC bond length
(13) (a) Gutierrez-Puebla, E.; Vegas, A.; Garcia-Blanco, S. Acta
Crystallogr., Sect. B 1978, 34, 3382. (b) Faville, S. J .; Henderson, W.;
Mathieson, T. J .; Nicholson, B. K. J . Organomet. Chem. 1999, 580,
363.
(14) Zhang, D.; McConville, D. B.; Tessier, C. A.; Youngs, W. J .
Organometallics 1997, 16, 824.

π-Coordination of Ag and Cu to Hg Bis-alkynyls
Organometallics, Vol. 19, No. 24, 2000 5213
and a near-planar geometry in the solid state (the mean
deviation from planarity is 0.14 Å).
The silver atoms of the 2,2′-N,N′-bipyridylsilver(I)
units are π-bonded to the ethynyl bonds of the mercury-
dialkynyl moieties; the Ag-C(1) and Ag-C(2) distances
are significantly asymmetric at 2.235(7) and 2.351(7)
Å, respectively. The Hg-C(1)-C(2)-C(8) chain is bent
away from the “trigonal planar” silver center, the angles
at C(1) and C(2) being 167.8(7) and 165.0(7) Å, respec-
tively. There is only a small (ca. 5°) torsional twist about
the C(2)-C(8) bond. The Hg-C distances [2.017(7) Å]
do not differ significantly from those observed in 1 and
5. In contrast, the CtC distance [1.209(11) Å] is
noticeably shorter than seen in 1 and 5, though it is
still longer than those observed in other mercury
dialkynyl species.13 The Ag-N(1) and Ag-N(2) bond
lengths are noticeably asymmetric at 2.252(6) and
2.306(7) Å, respectively, though this appears to be
commonplace in 2,2′-N,N′-bipyridylsilver complexes.
As in 5, the BF4 anions play an integral role in the
structure, “bridging” between the mercury and silver
centers (Figure 4). One of the fluorine atoms [F(1)]
makes a near orthogonal (ca. 82°) approach to the C(1)-
Hg-C(1′) fragment. The F‚‚‚Hg distance of 2.80(2) Å is
comparable to (if not shorter than) the shortest recorded
approach of a BF4 anion to a mercury center of 2.829 Å
in the structure of (η5-cyclopentadienyl)tricarbonyl-
triphenylphosphinomercury-molybdenum(II) tetrafluoro-
borate.16a However a contact of 2.814 Å to a fluorine
atom of an AsF6 anion has been reported.16b The Ag‚‚‚F
distance is significantly longer at 3.092(2) Å and longer
than the analogous contact in 5.
The complexes pack to form continuous π-π stacks
utilizing all three unique aromatic rings in the molecule
(Figure 5).
The shortest Hg‚‚‚Hg and Hg‚‚‚Ag nonbonded contacts
are 9.53 and 3.53 Å, respectively. We believe that the
bridging role played by the BF4- anions inhibits a more
regular stacking of the ring systems, which could
facilitate intermolecular Hg‚‚‚Hg and Ag‚‚‚Ag inter-
actions.
IR a n d 13C NMR Sp ectr oscop y. In addition to the
structural characterization of compounds 1, 5, and 12,
IR and 13C NMR spectroscopy of the species presented
in this paper are consistent with an η2 coordination of
the Cu(I) and Ag(I) ions to the alkynyl groups of [Hg-
(CtCR)2]. This is demonstrated by the shift of the
CtC stretch of all the compounds 1-17 to lower
frequencies as compared with those of the corresponding
starting materials [Hg(CtCR)2] (see Table 1). The
M-η2-(RCtCR) bond can be described in terms of the
Chatt-Duncanson-Dewar model with σ-donation from
a filled π-orbital of the triple bond to an empty orbital
of the metal center and a back-donation from a filled
metal d-orbital to the empty π* of the CtC moiety. As
has been discussed elsewhere, this leads to a decrease
in the covalent character of the triple bond and, as a
consequence, to a shift of the ν(CtC) to lower frequen-
cies.17
F igu r e 2. Molecular structure of 5, showing the π-linking
of adjacent ethynyl units by the silver atoms, and also the
anion and the included acetone molecule. The contact
distances (Å) are (a) 2.75, (b) 2.71, (c) 2.97, (d) 2.97, and
(e) 3.05 (50% probability ellipsoids).
The single-crystal X-ray analysis shows compound
{[Hg(CtCTol)2Ag][BF4]}n (5) to be polymeric with the
silver atom π-bonding approximately linearly between
the ethyne linkages of adjacent molecules (Figure 2).
Here the mercury dialkynyl complex does not have
inversion symmetry, and hence there are two unique
ethynyl units. The Ag-C bonds are, in each case,
asymmetric, with distances to C(1) and C(2) of 2.29(2)
and 2.42(2) Å, and to C(11) and C(12) of 2.27(2) and
2.43(2) Å, respectively. The bending of the Hg-CtC-
Ar linkage is less pronounced than in 1, with angles at
C(1), C(2), C(11), and C(12) of 173(2)°, 174(2)°, 172(2)°,
and 173(2)° respectively, and the aryl rings are rotated
substantially out of the C(1), C(2), C(8) and C(11), C(12),
C(18) planes by ca. 24° and 44° respectively. The Hg-C
distances of 2.00(2) and 2.02(2) Å do not differ signifi-
cantly from those in 1, and the CtC bond lengths [both
1.22(3) Å] are again toward the high side of the lengths
observed in other mercury-dialkynyl complexes.13
In this complex there are notable short contacts
involving both the BF4 anions and the included acetone
solvent molecules. The oxygen atom of the acetone
makes a short [2.75 Å] near-orthogonal (ca. 85°) ap-
proach to the C-Hg-C moiety. One of the fluorine
atoms [F(3)] makes a similar approach at 2.97 Å and a
significantly shorter approach to the silver atom of 2.71
Å (a distance comparable to intramolecular Ag‚‚‚F
distances15 but shorter than those normally observed
for anion-cation contact). Two of the other fluorine
atoms [F(1) and F(2)] make longer approaches of 3.05
and 2.97 Å, respectively, to a symmetry-related silver
center. These intermolecular interactions probably con-
tribute to the pitch of the helical polymer chain that is
created by the 21 screw axis. Adjacent helices interleave
with each other and are cross-linked by C-H‚‚‚π
interactions (a in Figure 3). The structure is chiral, and
hence all of the chains have a common helicity. The
shortest Hg‚‚‚Hg and Hg‚‚‚Ag nonbonded contacts are
5.66 and 3.44 Å, respectively.
The crystallographic analysis of compound [Hg-
(CtCR)2Ag2(bipy)2][BF4]2 (12) showed that as in 1 the
cations have crystallographic Ci symmetry (Figure 4)
(16) (a) Mullica, D. F.; Gipson, S. L.; Snell, L. C.; Sappenfield, E.
L.; Leschnitzer, D. H. Polyhedron 1992, 11, 2265. (b) Banister, A. J .;
Lavender, I.; Lawrence, S. E.; Rawson, J . M.; Clegg, W. J . Chem. Soc.,
Chem. Commun. 1994, 29.
(17) (a) Coates, G. E.; Parkin, C. J . Inorg. Nucl. Chem. 1961, 22,
59. (b) Abu-Salah, O. M. J . Organomet. Chem. 1990, 387, 123.
(15) (a) Uso´n, R.; Fornie´s, J .; Menjo´n, B.; Cotton, F. A.; Favello, L.
R.; Toma´s, M. Inorg. Chem. 1985, 24, 4651. (b) Uso´n, R.; Fornie´s, J .;
Toma´s, M.; Ara, I.; Casas, J . M.; Mart´ın, A. J . Chem. Soc., Dalton
Trans. 1991, 2253.

5214 Organometallics, Vol. 19, No. 24, 2000
Rais et al.
F igu r e 3. Cross-linking of a pair of adjacent helical chains in the structure of 5 by C-H‚‚‚π interactions (a). The H‚‚‚π
distance is 2.83 Å, and the C-H‚‚‚π angle is 146°.
compounds [Hg(CtCR)2] have chemical shifts between
108.7 and 121.0 ppm for CR and between 104.1 and
116.6 for Câ.19 Upon coordination of these species to
Cu(I) and Ag(I), the chemical shift of Câ remains
t
practically unchanged (except for the Bu-containing
compounds 3 and 14), while that for CR is shifted to
higher field. This suggests that the η2 interaction
between M(I) and the triple bond is not symmetrical
(which was demonstrated by the X-ray crystallographic
studies). The change in chemical shift of CR is larger
upon coordination to silver (10.1 ppm, R ) C6H5, and
11.7 ppm, R ) p-C6H4Me) than to copper (5.4 ppm, R )
C6H5, and 4.9 ppm, R ) p-C6H4Me). This difference is
F igu r e 4. Solid-state structure of 12 showing the planar
conformation of the cation and the “bridging” role of the
BF4 anions. The distances of the nonbonded F‚‚‚M contacts
are (a) 2.80(2); (b) 3.09(2) Å (50% probability ellipsoids).
also consistent with the crystallographic observations:
the η2 bond in the silver complexes is more asymmetric
than in the copper complexes.
Con clu sion s
A comparison between the IR spectra of the Cu(I) and
Ag(I) complexes shows that the copper compounds have
consistently lower CtC stretching frequencies than the
corresponding silver species, suggesting that Cu(I) binds
more strongly to the alkynyl groups than Ag(I). This
observation is consistent with previously reported
experimental9b and theoretical results.18
The mercury bis-alkynyl complexes [Hg(CtCR)2]
have been successfully used as building blocks for the
synthesis of polymetallic arrangements when they are
π-coordinated to Cu(I) and Ag(I). Spectroscopic and
structural characterization suggest that Cu(I) centers
coordinate more strongly to the triple bonds than the
Ag(I) ones, which is consistent with previously reported
data. The structural characterization of three of these
species (i.e., [Hg(CtCPh)2Cu2(CH3CN)4][PF6]2, {[Hg-
(CtCTol)2Ag][BF4]}n, and [Hg(CtCPh)2Ag2(bipy)2][BF4]2)
has shown the presence of interesting supramolecular
interactions. The extended planar metal-organic ar-
rangement exhibited by [Hg(CtCPh)2Ag2(bipy)2][BF4]2
is potentially a valuable system to study nonbonding
Hg‚‚‚Hg and Ag‚‚‚Ag interactions. In the current struc-
ture a more regular π-stacking between the molecules
Because of insolubility and stability problems, only
some of the metal-alkynyl species have been studied
by 13C{1H} NMR spectroscopy (see Table 5). Sharp and
well-defined peaks are observed for the carbon atoms
belonging to the R groups of the alkynyl moieties and
for the carbon atoms in the co-ligands. The most
important changes in chemical shift upon coordination
to Cu(I) and Ag(I) are obviously for the carbon atoms
in the CtC triple bonds. It has been previously estab-
t
lished that (with the exception of Bu derivative) the
-
seems to be inhibited by the presence of the BF4
counterions, which consequently prevents it from ex-
hibiting intermolecular metal-metal interactions. We
chemical shift for the CR (directly bonded to the mer-
cury) appears at a lower field than the Câ (carbon
directly linked to the R group).19 The simple bis-alkynyl
(19) Sebald, A.; Wrackmeyer, B. Spectrochim. Acta, Part A 1982,
38, 163.
(18) Kova´cs, A.; Frenking, G. Organometallics 1999, 18, 887.

π-Coordination of Ag and Cu to Hg Bis-alkynyls
Organometallics, Vol. 19, No. 24, 2000 5215
F igu r e 5. Part of the 3D-dimensional π-π stacking arrangement of the cations in 12. The centroid‚‚‚centroid and mean
interplanar separations (Å) are (a) 3.87, 3.46; (b) 3.89, 3.46; (c) 4.09, 3.56.
(15 mL) and added to a solution of [Hg(CtCPh)2] (0.62 g, 1.54
mmol) in toluene (30 mL). A white microcrystalline precipitate
formed immediately. The mixture was stirred for 1 h to ensure
completion of the reaction. The white precipitate was filtered
off, washed with toluene and diethyl ether, and dried in vacuo.
Evaporation of the mother liquor and addition of diethyl ether
rendered additional complex (yield 1.30 g, 86%). Anal. Found:
C, 29.43; H, 2.16; N, 5.49. Calcd for [C24Cu2F12H22HgN4P2]: C,
29.28; H, 2.24; N, 5.69. IR (Nujol): νmax/cm-1 2318s, 2291s
(CH3CN), 2022m, 1981s (CtC), 845vs (PF6). FAB+-MS: m/z
are currently studying the possibility of using different
anions (planar) or ligands (negatively charged) to favor
an appropriate arrangement of the molecules to show
such interactions. Also interesting is the novel polymeric
structure {[Hg(CtCTol)2Ag][BF4]}n. In this species the
BF4- anions also play an important structural role since
they help in keeping the mercury and silver atoms in a
fixed relative position. The variation of anions will
define the extent of their structural influence in this
polymeric arrangement. In summary the results pre-
sented in this paper demonstrate the variety of struc-
tures that can be obtained upon π-coordination of Ag(I)
and Cu(I) ions to the [Hg(CtCR)2] compounds. This
geometrically rigid species seems to be a good and
relatively unexplored building block for the design of
polymetallic aggregates.
549 {[Hg(CtCPh)2Cu(CH3CN)2]+}. 1H NMR [(CD3)2CO]:
δ
7.55-7.52 (m, 2H), 7.44-7.38 (m, 3H), 2.21 (s, 6H, CH3CN).
13C{1H} NMR [(CD3)2CO]: δ 1.0 (CH3CN), 108.4 (HgCtC),
115.6 (HgCtC), 122.4 (iC-C6H5), 128.9, 129.5 and 131.9
(C6H5), CH3CN signal was not observed.
Syn th esis of [Hg(CtCTol)2Cu 2(CH3CN)4][P F 6]2 (2). [Cu-
(CH3CN)4][PF6] (0.93 g, 2.50 mmol) was dissolved in CH2Cl2
(15 mL) and added to a solution of [Hg(CtCTol)2] (0.54 mg,
1.25 mmol) in toluene (20 mL) with a few drops of THF. A
white microcrystalline precipitate formed immediately. The
mixture was stirred for 1 h to ensure completion of the
reaction. The white precipitate was filtered off, washed with
toluene and diethyl ether, and dried in vacuo. Evaporation of
the mother liquor and addition of diethyl ether rendered
additional complex (yield 0.89 g, 70%). Anal. Found: C, 30.97;
H, 2.34; N, 4.95. Calcd for [C26Cu2H26HgF12N4P2]: C, 30.84;
H, 2.57; N, 5.53. IR (Nujol): νmax/cm-1 2321m, 2294m (CH3CN),
1981m (CtC), 843vs (PF6). FAB+-MS: m/z 577 {[Hg-
Exp er im en ta l Section
In str u m en ta tion . Infrared spectra were recorded on a
Perkin-Elmer FTIR1720 spectrometer as KBr disks or Nujol
mulls between 4000 and 400 cm-1, while polyethylene plates
were used between 400 and 180 cm-1. NMR spectra were
recorded on a J EOL GS 270 MHz spectrometer. 1H spectra
were referenced internally to the residual 1H impurity present
in the deuterated solvent. Chemical shifts in the 1H spectra
were reported in parts per million (ppm) relative to TMS. FAB-
(+) mass spectra were recorded on a VG Autospec spectrometer
using 3-NBA for the sample matrix. The ionizing radiation was
35 keV Cs+ primary ion beam. All the reactions were carried
out under an inert atmosphere of nitrogen using standard
Schlenk techniques. The reactions with silver compounds were
carried out with exclusion of light. [Hg(CtCR)2] (R ) C6H5,
p-C6H4Me, -C(CH3)3,)6 and [Cu(CH3CN)4][PF6]20 were synthe-
sized according to literature procedures. PhCtCH, TolCtCH,
(CH3)3CtCH, 2,2’-bipyridine, 1,10-phenanthroline, HgCl2,
[Ag(CH3CN)4][BF4], and AgBF4 were purchased from Aldrich
and used as received.
1
3
(CtCTol)2Cu(CH3CN)2]+}. H NMR (CD2Cl2): δ 7.42 (d, J )
8.2 Hz, 2H), 7.20 (d, 3J ) 7.9 Hz, 2H), 2.36 (s, 3H, C6H4-CH3),
2.22 (s, 6H, CH3CN). 13C{1H} NMR [(CD3)2CO]: δ 0.9 (CH3-
CN), 20.8 (C6H4-CH3), 108.8 (HgCtC), 114.8 (HgCtC), 119.3
(iC-C6H4-CH3), 129.5, 131.9, and 139.9 (C6H4-CH3), CH3CN
signal was not observed.
Syn th esis of [Hg(CtCtBu )2Cu 2(CH3CN)4][P F 6]2 (3). [Cu-
(CH3CN)4][PF6] (0.47 g, 1.27 mmol) was added in one portion
to a solution of [Hg(CtCtBu)2] (0.23 mg, 0.63 mmol) in THF
(20 mL). The pale yellow solution was stirred for 1 h.
Evaporation of most of the solvent under reduced pressure and
addition of diethyl ether yielded an off-white complex (yield
0.407 g, 68%). Anal. Found: C, 25.47; H, 3.10; N, 5.57. Calcd
for [C20Cu2H30HgF12N4P2]: C, 25.43; H, 3.18; N, 5.93. IR
(Nujol): νmax/cm-1 2321s, 2289s (CH3CN), 2011m (CtC), 836vs
(PF6). FAB+-MS: m/z 591 {[Hg(CtCtBu)2Cu(CH3CN)4]+}, 509
Syn th esis of [Hg(CtCP h )2Cu 2(CH3CN)4][P F 6]2 (1). [Cu-
(CH3CN)4][PF6] (1.14 g, 3.06 mmol) was dissolved in CH2Cl2
(20) Kubas, G. J . Inorg. Synth. 1979, Vol XIX, 90.

5216 Organometallics, Vol. 19, No. 24, 2000
Rais et al.
3
3
{[Hg(CtCtBu)2Cu(CH3CN)2]+}. 1H NMR [(CD3)2CO]: δ 2.26
(s, 6H, CH3CN), 1.29 (s, 9H, C(CH3)3). 13C{1H} NMR [(CD3)2-
CO]: δ 0.9 (CH3CN), 30.4 (C(CH3)3), 30.8 (C(CH3)3), 90.4
(HgCtC), 104.9 (HgCtC), 121.0 (CH3CN).
δ 8.84 (d, J ) 4.7 Hz, 2H), 8.36 (d, J ) 8.2 Hz, 2H), 8.26-
8.20 (m, 2H), 7.74-7.69 (m, 2H), 1.44 (s, 9H, C(CH3)3).
Syn th esis of [Hg(CtCP h )2Cu 2(p h en )2][P F 6]2 (9). 1,10-
Phenanthroline (0.05 g, 0.277 mmol) in CH2Cl2 (10 mL) was
added dropwise to a solution of [Hg(CtCPh)2Cu2(CH3CN)4]-
[PF6]2 (0.137 g, 0.139 mmol) in CH2Cl2 (10 mL). An off-white
precipitate formed immediately. The mixture was left to stir
for 1 h, then the precipitate was filtered off, washed with CH2-
Cl2 and with diethyl ether, and dried in vacuo (yield 0.107 g,
Syn th esis of {[Hg(CtCP h )2Ag][BF 4]}n (4). AgBF4 (0.10
g, 0.51 mmol) was added in one portion to a solution of [Hg-
(CtCPh)2] (0.21 g, 0.52 mmol) in THF (10 mL). The colorless
solution was stirred in the dark for 1 h, then filtered on a Celite
pad. The solution was concentrated under reduced pressure
and diethyl ether added, yielding a white compound (yield 0.16
65%). Anal. Found: C, 39.44; H, 1.94; N, 4.55. Calcd for [C40
Cu2F12H26HgN4P2‚1/2CH2Cl2]: C, 39.77; H, 2.21; N, 4.58. IR
(Nujol):
max/cm-1 1983m, 1963m (CtC), 1623m, 1603m,
-
g, 52%). Anal. Found: C, 32.03; H, 1.49. Calcd for [AgBC16F4H10
-
Hg]: C, 32.15; H, 1.67. IR (Nujol): νmax/cm-1 2094vs, (CtC),
1074br (BF4). FAB+-MS: m/z 511 {[Hg(CtCPh)2Ag]+}. 1H
NMR [(CD3)2CO]: δ 7.54-7.50 (m, 2H), 7.43-7.35 (m, 3H).
13C{1H} NMR [(CD3)2CO] δ 107.7 (HgCtC), 110.9 (HgCtC),
120.9 (iC-C6H5), 128.9, 129.9, and 132.7 (C6H5).
ν
1580m (CdN), 844vs (PF6). FAB+-MS: m/z 1035 {[Hg-
(CtCPh)2Cu2(phen)2][PF6]}+, 647 {[Hg(CtCPh)2Cu(bipy)]+}.
1H NMR [(CD3)2CO]: δ 9.05 (d, 3J ) 3.4 Hz, 2H), 8.97 (d, 3J )
8.2 Hz, 2H), 8.34 (s, 2H), 8.18-8.12 (m, 2H), 7.78-7.75 (m,
2H), 7.58-7.55 (m, 3H).
Syn th esis of {[Hg(CtCTol)2Ag][BF 4]}n (5). AgBF4 (0.094
g, 0.480 mmol) was added in one portion to a solution of [Hg-
(CtCTol)2] (0.209 g, 0.485 mmol) in THF (10 mL). The
colorless solution was stirred in the dark for 1 h, then filtered
on a Celite pad. The solution was concentrated under reduced
pressure and diethyl ether added, yielding a white compound
(yield 0.186 g, 61%). Anal. Found: C, 34.39; H, 2.12. Calcd for
Syn t h esis of [H g(CtCTol)2Cu 2(p h en )2][P F 6]2 (10).
1,10-Phenanthroline (0.06 g, 0.33 mmol) in CH2Cl2 (10 mL)
was added dropwise to a solution of [Hg(CtCTol)2Cu2(CH3-
CN)4][PF6]2 (0.169 g, 0.167 mmol) in CH2Cl2 (10 mL). An off-
white precipitate formed immediately. The mixture was left
to stir for 1 h, and then the precipitate was filtered off, washed
with CH2Cl2 and with diethyl ether, and dried in vacuo (yield
0.136 g, 67%). Anal. Found: C, 38.74; H, 2.18; N, 4.24. Calcd
for [C42Cu2F12H30HgN4P2‚1/2CH2Cl2]: C, 39.09; H, 2.47; N,
[AgBC18F4H14Hg]: C, 34.54; H, 2.24. IR (Nujol):
ν
max/cm-1
2090vs, (CtC), 1077br (BF4). FAB+-MS: m/z 539 {[Hg-
1
3
(CtCTol)2Ag]+}. H NMR [(CD3)2CO]: δ 7.42 (d, J ) 8.2 Hz,
2H), 7.18 (d, 3J ) 7.9 Hz, 2H), 2.34 (s, 3H, C6H4-CH3). 13C-
{1H} NMR [(CD3)2CO]: δ 20.7 (C6H4-CH3) 108.7 (HgCtC)
108.8 (HgCtC), 117.3 (iC-C6H4-CH3), 129.5, 132.9, and 140.6
(C6H4-CH3).
4.19. IR (Nujol):
ν
max/cm-1 1958m, 1937m (CtC), 1625m,
1605m, 1588m (CdN), 840vs (PF6). FAB+-MS: m/z 675 {[Hg-
(CtCTol)2Cu(phen)]+}. 1H NMR [(CD3)2CO]: δ 9.06 (d, 3J )
3
3.5 Hz, 2H), 8.95 (d, J ) 8.2 Hz, 2H), 8.33 (s, 2H), 8.11-8.06
(m, 2H), 7.75 (d,3J ) 7.9 Hz, 2H), 7.45 (d,3J ) 8.1 Hz, 2H),
2.47 (s, 3H, C6H4-CH3).
Syn th esis of [Hg(CtCP h )2Cu 2(bip y)2][P F 6]2 (6). 2,2’-
Bipyridine (0.05 g, 0.320 mmol) was dissolved in CH2Cl2 (15
mL) and added dropwise to a solution of [Hg(CtCPh)2Cu2(CH3-
CN)4][PF6]2 (0.16 g, 0.163 mmol) in CH2Cl2 (15 mL). A pale
orange solution formed, which, after ca. 15 min, yielded a white
precipitate. The suspension was stirred for 1 h. The precipitate
was then filtered off and washed with CH2Cl2 and diethyl ether
(yield 0.11 g, 59%). Anal. Found: C, 37.90; H, 2.12; N, 4.85.
Calcd for [C36Cu2F12H26HgN4P2]: C, 38.17; H, 2.30; N, 4.95.
IR (Nujol): νmax/cm-1 1967w, 1951w (CtC), 1604m, 1594m
(CdN), 844vs (PF6). FAB+-MS: m/z 987 {[Hg(CtCPh)2Cu2-
(bipy)2][PF6]}+, 623 {[Hg(CtCPh)2Cu(bipy)]+}. 1H NMR [(CD3)2-
CO]: δ 8.73 (d, 3J ) 8.2 Hz, 2H), 8.65 (d, 3J ) 4.7 Hz, 2H),
8.43-8.34 (m, 2H), 7.83-7.74 (m, 4H), 7.55-7.64 (m, 3H).
Syn t h esis of [H g(CtCTol)2Cu 2(b ip y)2][P F 6]2 (7). 2,2’-
Bipyridine (0.13 g, 0.8 mmol) was dissolved in CH2Cl2 (5 mL)
and added to a solution of [Hg(CtCTol)2Cu2(CH3CN)4][PF6]2
(0.41 g, 0.4 mmol) in CH2Cl2 (20 mL). The purple solution was
stirred for 1 h. Evaporation of the solvent under reduced
pressure and addition of diethyl ether yielded an off-white
compound (yield 0.42 g, 90%). Anal. Found: C, 39.12; H, 2.52;
N, 4.62. Calcd for [C38Cu2F12H30HgN4P2]: C, 39.32; H, 2.59;
N, 4.83. IR (Nujol): νmax/cm-1 1968m, 1941m (CtC), 1600vs,
1567w (CdN), 842vs (PF6). FAB+-MS: m/z 1017 {[Hg-
(CtCTol)2Cu2(bipy)2][PF6]}+, 651 {[Hg(CtCTol)2Cu(bipy)]+}.
1H NMR [(CD3)2CO]: δ 8.71 (d, 3J ) 8.2 Hz, 2H), 8.65 (d, 3J )
4.4 Hz, 2H), 8.40-8.34 (m, 2H), 7.80-7.76 (m, 2H), 7.63 (d, 3J
) 8.2 Hz, 2H), 7.38(d, 3J ) 7.9 Hz, 2H), 2.42 (s, 3H, C6H4-
CH3).
Syn t h esis of [H g(CtCt Bu )2Cu 2(p h en )2][P F 6]2 (11).
1,10-Phenanthroline (0.17 g, 0.94 mmol) in CH2Cl2 (10 mL)
was slowly added to a solution of [Hg(CtCtBu)2Cu2(CH3CN)4]-
[PF6]2 (0.44 g, 0.47 mmol) in CH2Cl2 (10 mL). A purple solution
formed immediately, which then turned pale, yielding a white
precipitate. The mixture was left to stir for 1 h, and then the
precipitate was filtered off, washed with CH2Cl2 and with
diethyl ether, and dried in vacuo (yield 0.38 g, 71%). Anal.
Found: C, 37.77; H, 2.85; N, 4.82. Calcd for [C36Cu2F12H34
-
HgN4P2]: C, 37.89; H, 2.98; N, 4.91. IR (Nujol): νmax/cm-1
1964m (CtC), 1625m, 1605m, 1582m (CdN), 843vs (PF6).
FAB+-MS: m/z 995 {[Hg(CtCtBu)2Cu2(phen)2][PF6]}+, 607
{[Hg(CtCtBu)2Cu(bipy)]+}. 1H NMR [(CD3)2CO]: δ 9.51 (s, br,
2H), 9.46 (d, 3J ) 8.2 Hz, 2H), 8.34 (s, 2H), 8.20-8.14 (m, 2H),
1.51 (s, 9H, C(CH3)3).
Syn th esis of [Hg(CtCP h )2Ag2(bip y)2][BF 4]2 (12). AgBF4
(0.20 g, 1.04 mmol) was added to a solution of [Hg(CtCPh)2]
(0.21 g, 0.522 mmol) in THF (10 mL). The pale yellow solution
was stirred in the dark for 1 h. 2,2’-Bipyridine (0.162 g, 1.04
mmol) was then added in one portion, yielding a pale yellow
solid, which was stirred for 15 min, filtered, and washed with
THF (yield 0.51 g, 88%). Anal. Found: C, 39.18; H, 2.38; N,
5.23. Calcd for [Ag2B2C36F8H26HgN4]: C, 39.12; H, 2.35; N,
4.87. IR (Nujol):
ν
max/cm-1 2049m, 1995w (CtC), 1592m,
1567w (CdN), 1058br (BF4). FAB+-MS: m/z 667 {[Hg-
(CtCPh)2Ag(bipy)]+}. 1H NMR [(CD3)2CO]: δ 8.83 (d, 3J ) 4.4
3
Hz, 2H), 8.56 (d, J ) 8.1 Hz, 2H), 8.28-8.18 (m, 2H), 7.78-
7.68 (m, 2H), 7.61-7.51 (br, 2H), 7.44-7.37 (m, 3H).
Syn t h esis of [Hg(CtCt Bu )2Cu 2(b ip y)2][P F 6]2 (8). 2,2’-
Bipyridine (0.081 g, 0.52 mmol) was dissolved in CH2Cl2 (5
mL) and added to a solution of [Hg(CtCtBu)2Cu2(CH3CN)4]-
[PF6]2 (0.25 g, 0.26 mmol) in CH2Cl2 (20 mL). A white
precipitate formed immediately. This was stirred for 1 h to
ensure completion of the reaction. It was then filtered off,
washed with CH2Cl2, and dried in vacuo (yield 0.17 g, 60%).
Syn th esis of [Hg(CtCTol)2Ag2(bip y)2][BF 4]2 (13). AgBF4
(0.106 g, 0.54 mmol) was added to a solution of [Hg(CtCTol)2]
(0.117 g, 0.27 mmol) in THF (10 mL). The pale yellow solution
was stirred in the dark for 1 h. 2,2’-Bipyridine (0.084 g, 0.54
mmol) was then added, yielding a pale yellow solid, which was
stirred for 15 min, filtered, and washed with THF (yield 0.24
g, 78%). Anal. Found: C, 40.43; H, 2.72; N, 4.96. Calcd for
[Ag2B2C38F8H30HgN4]: C, 40.27; H, 2.65; N, 4.94. IR (Nujol):
Anal. Found: C, 35.09; H, 2.91; N, 5.00. Calcd for [C32
-
Cu2F12H34HgN4P2]: C, 35.16; H, 3.11; N, 5.13. IR (Nujol): νmax
/
ν
max/cm-1 2063m, 1997w (CtC), 1590m, 1574w (CdN), 1051br
cm-1 1947s (CtC), 1600vs, 1568w (CdN), 838vs (PF6). FAB+-
MS: m/z 583 {[Hg(CtCtBu)2Cu(bipy)]+}. 1H NMR (CD2Cl2):
(BF4). FAB+-MS: m/z 1047 {[Hg(CtCTol)2Ag2(bipy)2][BF4]}+
1
, 695 {[Hg(CtCTol)2Ag(bipy)]+}. H NMR [(CD3)2CO]: δ 8.84

π-Coordination of Ag and Cu to Hg Bis-alkynyls
Organometallics, Vol. 19, No. 24, 2000 5217
3
(br, 2H), 8.60 (br, 2H), 8.26 (br, 2H), 7.75 (br, 2H), 7.45 (d, J
Cr ysta l d a ta for 1: [C24H22N4Cu2Hg][PF6]2‚1.3H2O, M )
1007.5, triclinic, space group P1h (no. 2), a ) 8.482(1), b )
8.706(1), c ) 12.081(1) Å, R ) 87.67(1)°, â ) 74.93(1)°, γ )
83.03(1)°, V ) 855.0(2) Å3, Z ) 1 (the complex has crystal-
lographic Ci symmetry), Dc ) 1.957 g cm-3, µ(Cu KR) ) 11.1
mm-1, F(000) ) 483, T ) 293 K; clear needles, 0.67 × 0.04 ×
0.03 mm, Siemens P4/RA diffractometer, graphite-monochro-
mated Cu KR radiation, ω-scans, 2698 independent reflections.
The structure was solved by the heavy atom method, and the
non-hydrogen atoms were refined anisotropically using full-
3
) 8.2 Hz, 2H), 7.22 (d, J ) 7.9 Hz, 2H), 2.35 (s, 3H).
Syn th esis of [Hg(CtCtBu )2Ag2(bip y)2][BF 4]2 (14). Ag-
BF4 (0.34 g, 1.75 mmol) was added to a solution of [Hg(CtCt-
Bu)2] (0.32 g, 0.88 mmol) in CHCl3 (10 mL). The pale yellow
solution was stirred in the dark for 15 min. 2,2’-Bipyridine
(0.27 g, 1.74 mmol) was then added, yielding a white solid,
which was stirred for 15 min, filtered, and washed with CHCl3
and then with diethyl ether (yield 0.68 g, 73%). Anal. Found:
C, 36.25; H, 3.08; N, 5.41. Calcd for [Ag2B2C32F8H34HgN4]: C,
36.08; H, 3.19; N, 5.26. IR (Nujol): νmax/cm-1 2053m (CtC),
1590m, 1576w (CdN), 1062br (BF4) FAB+-MS: m/z 979 {[Hg-
(CtCtBu)2Ag2(bipy)2][BF4]}+ , 627 {[Hg(CtCtBu)2Ag(bipy)]+}.
matrix least-squares based on F2 to give R1 ) 0.042, wR2
)
0.104 for 2502 independent observed absorption corrected
reflections [|Fo| > 4σ(|Fo|), 2θ e 128°] and 257 parameters.
CCDC 149436.
1H NMR (CD2Cl2): δ 8.75 (d, J ) 4.4 Hz, 2H), 8.25 (d, J )
8.2 Hz, 2H), 8.11-8.04 (m, 2H), 7.61-7.58 (m, 2H), 1.43 (s,
9H). 13C{1H} NMR (CD2Cl2): δ 29.9 (C(CH3)3), 32.1 (C(CH3)3)
94.6 (HgCtC), 121.7 (HgCtC), 122.9, 126.2, 139.9, 151.1,
151.1, and 151.1 (bipy).
Syn th esis of [Hg(CtCP h )2Ag2(p h en )2][BF 4]2 (15). Ag-
BF4 (0.28 g, 1.4 mmol) was added to a solution of [Hg(CtCPh)2]
(0.29 g, 0.72 mmol) in THF (10 mL). The pale yellow solution
was stirred in the dark for 1 h. 1,10-Phenanthroline (0.25 g,
1.4 mmol) was then added, yielding a pale yellow solid, which
was stirred for 15 min, filtered, and washed with THF (yield
0.62 g, 75.0%). Anal. Found: C, 41.51; H, 2.07; N, 4.86. Calcd
for [Ag2B2C40F8H26HgN4]: C, 41.65; H, 2.25; N, 4.86. IR
3
3
Cr ysta l d a ta for 5: {[C18H14AgHg][BF4]‚Me2CO}n, M )
683.6, monoclinic, space group P21 (no. 4), a ) 10.472(2), b )
8.927(2), c ) 11.806(2) Å, â ) 97.04(1)°, V ) 1095.3(4) Å3, Z )
2, Dc ) 2.073 g cm-3, µ(Mo KR) ) 7.94 mm-1, F(000) ) 644, T
) 203 K; clear platy prisms, 0.37 × 0.17 × 0.07 mm, Siemens
P4/PC diffractometer, graphite-monochromated Mo KR radia-
tion, ω-scans, 1932 independent reflections. The structure was
solved by the heavy atom method, and the non-hydrogen atoms
were refined anisotropically using full-matrix least-squares
based on F2 to give R1 ) 0.041, wR2 ) 0.088 for 1640
independent observed absorption corrected reflections [|Fo| >
4σ(|Fo|), 2θ e 50°] and 262 parameters. The absolute chirality
max/cm-1 2058m (CtC), 1621m, 1591w, 1574w
of 5 was determined by a combination of R-factor tests [R1
)
+
(Nujol):
ν
(CdN), 1057br (BF4). FAB+-MS: m/z 691 {[Hg(CtCPh)2Ag-
(phen)]+}. 1H NMR [(CD3)2CO]: δ 9.19 (d, 3J ) 3.5 Hz, 2H),
8.77 (d, 3J ) 8.2 Hz, 2H), 8.2 (s, 2H), 8.04-7.99 (m, 2H), 7.59-
7.56 (m, 2H), 7.43-7.38 (m, 3H).
0.0405, R1 ) 0.0504] and by use of the Flack parameter [x+
) -0.03(3)]. CCDC 149437.
-
Cr ysta l d a ta for 12: [C36H26N4Ag2Hg][BF4]2, M ) 1104.6,
triclinic, space group P1h (no. 2), a ) 9.525(2), b ) 10.051(2), c
) 10.775(2) Å, R ) 72.75(1)°, â ) 84.61(1)°, γ ) 62.09(1)°, V )
869.3(3) Å3, Z ) 1 (the complex has crystallographic Ci
symmetry), Dc ) 2.110 g cm-3, µ(Mo KR) ) 5.60 mm-1, F(000)
) 526, T ) 293 K; clear platy prisms, 0.23 × 0.17 × 0.08 mm,
Siemens P4/PC diffractometer, graphite-monochromated Mo
KR radiation, ω-scans, 3012 independent reflections. The
structure was solved by the heavy atom method, and the non-
hydrogen atoms were refined anisotropically using full-matrix
least-squares based on F2 to give R1 ) 0.036, wR2 ) 0.069 for
2268 independent observed absorption corrected reflections
[|Fo| > 4σ(|Fo|), 2θ e 50°] and 265 parameters. CCDC 149438.
Syn th esis of [Hg(CtCTol)2Ag2(p h en )2][BF 4]2 (16). Ag-
BF4 (0.78 g, 4 mmol) was added to a solution of [Hg(CtCTol)2]
(0.86 g, 2 mmol) in THF (10 mL). The pale yellow solution was
stirred in the dark for 1 h. 1,10-Phenanthroline (0.72 g, 4
mmol) was then added, yielding a pale yellow solid, which was
stirred for 15 min, filtered, and washed with THF (yield 2.14
g, 90%). Anal. Found: C, 42.88; H, 2.59; N, 4.68. Calcd for
[Ag2B2C42F8H30HgN4]: C, 42.70; H, 2.54; N, 4.74. IR (Nujol):
ν
max/cm-1 2051w, 2038w (CtC), 1621m, 1590w, 1574w
(CdN), 1055br (BF4). FAB+-MS: m/z 1093 {[Hg(CtCTol)2Ag2-
(phen)2][BF4]+}, 719 {[Hg(CtCTol)2Ag(phen)]+}. 1H NMR
3
3
[(CD3)2CO]: δ 9.21 (d, J ) 3.5 Hz, 2H), 8.82 (d, J ) 8.2 Hz,
2H), 8.24 (s, 2H), 8.09-8.04 (m, 2H), 7.47 (d, 3J ) 7.9 Hz, 2H),
7.22 (d, J ) 7.9 Hz, 2H), 2.36 (s, 3H).
Ack n ow led gm en t. We thank BP plc for endowing
D.M.P.M.’s chair and the Department of Chemistry,
Imperial College, for financial support to D.R.
3
Syn th esis of [Hg(CtCtBu )2Ag2(p h en )2][BF 4]2 (17). Ag-
BF4 (0.35 g, 1.8 mmol) was added to a solution of [Hg-
(CtCtBu)2] (0.326 g, 0.9 mmol) in THF (10 mL). The pale
yellow solution was stirred in the dark for 1 h. 1,10-Phenan-
throline (0.324 g, 1.8 mmol) was then added, yielding a pale
yellow solid, which was stirred for 15 min, filtered, and washed
with THF (yield 0.83 g, 83%). Anal. Found: C, 38.76; H, 2.85;
N, 5.15. Calcd for [Ag2B2C36F8H34HgN4]: C, 38.84; H, 3.05; N,
Su p p or tin g In for m a tion Ava ila ble: Details about the
X-ray crystal structures, including ORTEP diagrams, and
tables of crystal data and structure refinement, atomic coor-
dinates, bond lengths and angles, and anisotropic displacement
parameters for 1, 5, and 12. This material is available free of
charge via the Internet at http://pubs.acs.org.
5.03. IR (Nujol):
1573m (CdN), 1065br (BF4).
ν
max/cm-1 2049m (CtC), 1620m, 1590m,
OM000564B