Binuclear gold(I) and mercury(II) derivatives of diethynylfluorenes

Article abstract of DOI:10.1021/om0106229

A new series of bis(alkynyl) gold(I) and mercury(II) d¹⁰ complexes incorporating fluorenyl-based based linking units are reported. The binuclear complexes [LAuC≡CRC≡CAuL] and their isoelectronic mercury(II) congeners [R′HgC≡CRC≡CHgR′] (L = tertiary phosphines; R = fluorene-2,7-diyl, dihexylfluorene-2,7-diyl, 9-((ferrocenylphenylene)methylene)fluorene-2,7-diyl, fluoren-9-one-2,7-diyl, 9-(dicyanomethylene)fluorene-2,7-diyl; R′ = Me, Ph) were prepared in very good yields by the base-catalyzed dehydrohalogenation reaction of the corresponding metal chloride precursors with the appropriate diethynylfluorene derivatives HC≡CRC≡CH at room temperature. All the compounds have been fully characterized by FTIR, NMR and electronic absorption spectroscopies and FAB mass spectrometry. The solid-state molecular structures of [Ph₃PAuC≡CRC≡CAuPPh₃] (R = 9,9-dihexylfluorene-2,7-diyl, fluoren-9-one-2,7-diyl) and [MeHgC≡CRC≡CHgMe] (R = fluoren-9-one-2.7-diyl) have been determined crystallographically, the last of which represents the first dimercury diacetylide to be structurally characterized. Absorption studies suggest that it is possible to fine-tune the optical gap of this class of materials by modifying the electronic properties of the substituent at the 9-position of the central fluorene spacer. The solution redox chemistry of these fluorene-linked binuclear complexes as revealed by cyclic voltammetry indicates some degree of electronic communication between the 9-substituent of the fluorenyl ring and the terminal metal groups via the conjugated alkynyl bridge. Most of the complexes in this study have been shown to exhibit rich photophysical behavior, and a discussion on their emission properties in terms of the nature of metal groups and their auxiliary ligands as well as the fluorene spacer was made.

Full text of DOI:10.1021/om0106229

5446
Organometallics 2001, 20, 5446-5454
Bin u clea r Gold (I) a n d Mer cu r y(II) Der iva tives of
Dieth yn ylflu or en es
Wai-Yeung Wong,* Ka-Ho Choi, Guo-Liang Lu, J ian-Xin Shi, Pui-Yan Lai, and
Sze-Man Chan
Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong,
Hong Kong, People’s Republic of China
Zhenyang Lin
Department of Chemistry, The Hong Kong University of Science and Technology,
Clearwater Bay, Hong Kong, People’s Republic of China
Received J uly 12, 2001
A new series of bis(alkynyl) gold(I) and mercury(II) d10 complexes incorporating fluorenyl-
based linking units are reported. The binuclear complexes [LAuCtCRCtCAuL] and their
isoelectronic mercury(II) congeners [R′HgCtCRCtCHgR′] (L ) tertiary phosphines; R )
fluorene-2,7-diyl, dihexylfluorene-2,7-diyl, 9-((ferrocenylphenylene)methylene)fluorene-2,7-
diyl, fluoren-9-one-2,7-diyl, 9-(dicyanomethylene)fluorene-2,7-diyl; R′ ) Me, Ph) were
prepared in very good yields by the base-catalyzed dehydrohalogenation reaction of the
corresponding metal chloride precursors with the appropriate diethynylfluorene derivatives
HCtCRCtCH at room temperature. All the compounds have been fully characterized by
FTIR, NMR and electronic absorption spectroscopies and FAB mass spectrometry. The solid-
state molecular structures of [Ph3PAuCtCRCtCAuPPh3] (R ) 9,9-dihexylfluorene-2,7-diyl,
fluoren-9-one-2,7-diyl) and [MeHgCtCRCtCHgMe] (R ) fluoren-9-one-2,7-diyl) have been
determined crystallographically, the last of which represents the first dimercury diacetylide
to be structurally characterized. Absorption studies suggest that it is possible to fine-tune
the optical gap of this class of materials by modifying the electronic properties of the
substituent at the 9-position of the central fluorene spacer. The solution redox chemistry of
these fluorene-linked binuclear complexes as revealed by cyclic voltammetry indicates some
degree of electronic communication between the 9-substituent of the fluorenyl ring and the
terminal metal groups via the conjugated alkynyl bridge. Most of the complexes in this study
have been shown to exhibit rich photophysical behavior, and a discussion on their emission
properties in terms of the nature of metal groups and their auxiliary ligands as well as the
fluorene spacer was made.
In tr od u ction
design of linear-chain metal-containing materials with
extensive electronic conjugation.2,3 It has been shown
that some of these gold(I) complexes show liquid-
crystalline properties4 or nonlinear optical behavior.5 In
addition, many alkynylgold(I) derivatives exhibit diverse
and interesting luminescent properties.3,6 In particular,
alkynylgold(I) compounds with tertiary phosphine ligands
are well-known for their rich photochemistry and belong
to a class of luminophores that may find applications
in electronic devices.6,7 In view of the fact that the
There is a rapidly growing interest in the study and
design of rigid-rod metal acetylide materials due to the
potential applications of these compounds in many areas
of materials science.1 Among these, the chemistry of
alkynylgold(I) complexes has received much current
attention.2,3 The preference of d10 gold(I) to form linear
two-coordinate species, along with the linearity of the
CtC bond in alkynyl ligands, make the -(AuCtC)-
moiety an attractive and promising candidate for the
(3) (a) Mu¨ller, T. E.; Choi, S. W.-K.; Mingos, D. M. P.; Murphy, D.;
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tallics 1996, 15, 51. (c) Altmann, M.; Bunz, U. H. F. Angew. Chem.,
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* To whom correspondence should be addressed. E-mail: rwywong@
hkbu.edu.hk.
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Wiley: Chichester, U.K., 1996. (b) Manners, I. Angew. Chem., Int. Ed.
Engl. 1996, 35, 1602. (c) Kingsborough, R. P.; Swager, T. M. Prog.
Inorg. Chem. 1999, 48, 123.
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J .; Chicote, M.-T.; Abrisqueta, M.-D. Organometallics 1997, 16, 5628.
(c) Yam, V. W.-W.; Choi, S. W.-K.; Cheung, K.-K. Organometallics 1996,
15, 1734. (d) Payne, N. C.; Ramachandran, R.; Puddephatt, R. J . Can.
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10.1021/om0106229 CCC: $20.00 © 2001 American Chemical Society
Publication on Web 11/13/2001

Au(I) and Hg(II) Derivatives of Diethynylfluorenes
Organometallics, Vol. 20, No. 25, 2001 5447
[R′Hg]+ unit (R′ ) alkyl, aryl) is isoelectronic and
isolobal with the [Ph3PAu]+ fragment,8 a comparative
study of the alkynylmercury(II) complexes to their gold-
(I) counterparts represents a challenging area of re-
search. Despite a vast number of works on the chemistry
of alkynylgold(I) species, much less is known for the
mercury(II) congeners and related studies on the iso-
electronic mercury(II) systems are still sparse. Orga-
nomercurials, particularly methyl- and arylmercury(II)
compounds, are the most deleterious mercury contami-
nant agents that take part in the biogeochemical cycle
of mercury.9 Considerable effort has been devoted to the
search for rapid and sensitive separation and detection
methods for these toxic mercury species.10,11 With the
recent reports on the successful development of new
derivatization procedures which convert Hg(II) and
MeHg(II) species into organometallic compounds suit-
able for chromatographic analyses11 and the recent
efforts by us and others in employing fluorene-based
spacers to make luminescent bimetallic and organome-
tallic polymeric materials,12 it seemed an attractive goal
to us to synthesize new d10 metal complexes with
electronically tunable fluorenyl linkers, I-V (Chart 1).
Here we report the first synthesis, characterization, and
redox and luminescence behavior of a series of novel bis-
(alkynyl)gold(I) and -mercury(II) complexes [LAuCt
CRCtCAuL] and [R′HgCtCRCtCHgR′] (L ) tertiary
phosphines; R ) fluorenyl groups; R′ ) Me, Ph) with
electron-rich and electron-deficient fluorene moieties,
Ch a r t 1
and the first structurally characterized dimercury(II)
diacetylide complex is also presented. Their luminescent
behavior will be discussed in terms of the electronic,
geometric, and steric properties of L, R, and R′.
Resu lts a n d Discu ssion
Syn th esis. The ligand precursors I and IV were
prepared by previously reported procedures.12a 9,9-
Dihexyl-2,7-bis((trimethylsilyl)ethynyl)fluorene was pre-
pared as a white crystalline solid by the Sonogashira
coupling reaction of Me3SiCtCH with 9,9-dihexyl-2,7-
dibromofluorene.13 The ferrocenyl species 9-((ferroce-
nylphenylene)methylene)-2,7-bis((trimethylsilyl)ethynyl)-
fluorene was made by condensing 2,7-bis((trimethylsilyl)-
ethynyl)fluorene12a with 4-ferrocenylbenzaldehyde14 in
the presence of iPr2NLi and isolated as an orange solid.
9-(Dicyanomethylene)-2,7-bis((trimethylsilyl)ethynyl)-
fluorene was obtained as a dark brown powder from the
reaction of the fluoren-9-one derivative with malononi-
trile in DMSO at 110 °C.15 Conversion of these Me3Si-
substituted compounds into the diterminal H deriva-
tives II, III, and V was accomplished by desilylation
with K2CO3 in MeOH (for II and III) or Bu4NF (for V)
at room temperature. The yields of these reactions are
high.
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Scheme 1 outlines the reactions leading to the new
fluorene-linked digold(I) and dimercury(II) complexes.
The precursors I-V can be used to form binuclear
alkynyl complexes of Au(I) and Hg(II) by the classical
dehydrohalogenation reaction between alkynes and
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P.; Midollini, S.; Orlandini, A.; Vacca, A. J . Chem. Soc., Chem.
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5448 Organometallics, Vol. 20, No. 25, 2001
Wong et al.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
Sch em e 1
(d eg) for 2‚0.5C6H14
Au(1)-C(19)
Au(2)-C(47)
C(19)-C(20)
C(46)-C(47)
2.003(5)
1.985(6)
1.181(7)
1.202(8)
Au(1)-P(1)
Au(2)-P(2)
C(20)-C(21)
C(27)-C(46)
2.281(1)
2.270(1)
1.448(7)
1.443(7)
C(19)-Au(1)-P(1)
175.9(2) Au(1)-C(19)-C(20) 172.6(6)
177.1(2)
C(19)-C(20)-C(21) 178.4(6) C(47)-Au(2)-P(2)
Au(2)-C(47)-C(46) 175.8(6) C(27)-C(46)-C(47) 179.1(7)
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4
Au(1)-C(19)
Au(2)-C(35)
C(19)-C(20)
C(34)-C(35)
1.99(1)
2.022(9)
1.23(2)
1.16(2)
Au(1)-P(1)
Au(2)-P(2)
C(20)-C(21)
C(27)-C(34)
2.273(3)
2.276(3)
1.37(2)
1.48(2)
C(19)-Au(1)-P(1)
175.3(4) Au(1)-C(19)-C(20) 167(1)
C(19)-C(20)-C(21) 175(1)
Au(2)-C(35)-C(34) 165(1)
C(35)-Au(2)-P(2)
170.6(3)
C(27)-C(34)-C(35) 174(2)
sign of the formation of bis(mercurial) species could be
detected and the reaction only occurred with partial
decomposition to metallic mercury. The reaction be-
tween 11 and malononitrile in DMSO has also been
attempted and seemed to produce a complex mixture
which we could not separate.
Sp ectr oscop ic a n d Str u ctu r a l Ch a r a cter iza tion .
All the new complexes in this study display weak IR
ν(CtC) absorptions at ca. 2095-2113 cm-1 (for Au(I))
and 2121-2130 cm-1 (for Hg(II)). The CtCH stretching
mode in the starting material is absent in each case.
The characteristic IR vibration due to ν(CdO) is appar-
ent in all fluorenone-containing alkynyl complexes at
ca. 1712-1717 cm-1, whereas complex 7 also gave ν(Ct
chlorogold(I) phosphine complexes or alkylmercury(II)
chlorides in the presence of a base.11c,16 Treatment of 2
equiv of [AuCl(L)] with each of the bifunctional diethy-
nylfluorene ligands HCtCRCtCH in an excess of basic
MeOH afforded the digold(I) diacetylide complexes
[LAuCtCRCtCAuL] (L ) PPh3, R ) fluorene-2,7-diyl
(1), 9,9-dihexylfluorene-2,7-diyl (2), 9-((ferrocenylphe-
nylene)methylene)fluorene-2,7-diyl (3), fluoren-9-one-
2,7-diyl (4), 9-(dicyanomethylene)fluorene-2,7-diyl (7);
L ) PMe3, R ) fluoren-9-one-2,7-diyl (5); L ) PAnPh2,
An ) anthracenyl, R ) fluoren-9-one-2,7-diyl (6)) in very
good yields, which readily precipitated from the solution
mixture. Likewise, we were able to isolate the isoelec-
tronic Hg(II) compounds [R′HgCtCRCtCHgR′] (R′ )
Me, R ) fluorene-2,7-diyl (8), 9,9-dihexylfluorene-2,7-
diyl (9), 9-((ferrocenylphenylene)methylene)fluorene-2,7-
diyl (10), fluoren-9-one-2,7-diyl (11); R′ ) Ph, R )
fluoren-9-one-2,7-diyl (12)) from MeHgCl or PhHgCl
under similar experimental conditions.11c Once again,
the product yields of 8-12 are very high (80-95%). All
the new complexes were obtained as air-stable solids
in high purity and found to be soluble in chlorinated
solvents such as CH2Cl2. They all gave satisfactory
analytical data and were characterized by fast atom
bombardment mass spectrometry (FAB-MS) and IR and
NMR spectroscopy. The X-ray structures of compounds
2, 4, and 11 were also determined. However, all at-
tempts to prepare the bis(mercurial) analogue of 7,
[MeHgCtCRCtCHgMe] (R ) 9-(dicyanomethylene)-
fluorene-2,7-diyl), failed. The direct reaction of MeHgCl
and V in basic MeOH only led to the isolation of
compound 11, probably due to the attack of MeO- on
the CdC(CN)2 group. Using the CuI/iPr2NH system, no
1
N) 2224 cm-1. In the H NMR spectra, proton signals
arising from the aromatic and other organic groups were
observed. Except for 3 and 10, the symmetrical nature
of all other complexes was evident from the NMR
spectral pattern. The room-temperature 31P NMR spec-
trum of 3 displays two sharp singlets in close proximity
at δ 43.46 and 43.70, indicating an unsymmetrical
arrangement of PAuCtC groups in solution. The fer-
rocenyl moieties in 3 and 10 show the expected pattern
where the unsubstituted C5H5 ring appears as a strong
singlet and the monosubstituted C5H4 ring gives an
unsymmetrical pair of “pseudo” triplets corresponding
to the A2B2 spectrum with J (adjacent) = J (cross). In
each case, we can locate an intense molecular ion peak
in the respective mass spectrum.
Although a slight difficulty in growing single crystals
of these bis(alkynyl)gold(I) and -mercury(II) complexes
was encountered, X-ray structure determinations were
successfully carried out for three of them. We are aware
that there are only a few structurally characterized
examples of digold(I) diacetylide complexes in the
literature,3c-e the first one being [Me3PAuCtCC6H2-
Me2CtCAuPMe3], reported by Puddephatt and co-
workers.3c The perspective drawings of 2 and 4 with
atomic numberings are shown in Figures 1 and 2,
respectively. Selected bond lengths and angles are
presented in Tables 1 and 2. There is a half hexane
solvate in the unit cell of compound 2. In contrast to
many Au(I) compounds, where there frequently exist
short Au‚‚‚Au intermolecular contacts,6 no such weak
interactions are observed in 2 and 4 in the solid state,
as the sterically bulky phenyl groups of the phosphine
(16) (a) Coates, G. E.; Parkin, C. J . Chem. Soc. 1962, 3220. (b) Bruce,
M. I.; Horn, M. I.; Matisons, J . G.; Snow, M. R. Aust. J . Chem. 1984,
37, 1163. (c) Cross, R. J .; Davidson, M. F.; McLennan, A. J . J .
Organomet. Chem. 1984, 265, C37.

Au(I) and Hg(II) Derivatives of Diethynylfluorenes
Organometallics, Vol. 20, No. 25, 2001 5449
F igu r e 1. Perspective drawing of compound 2.
F igu r e 2. Perspective drawing of compound 4.
ligands and the long hexyl chains (for 2) probably
prevent their close approach.2c The closest intramolecu-
lar nonbonded contact in 2 is due to an Au(2)‚‚‚H(55A)
interaction (3.022 Å), and the nearest intermolecular
contact arises from an Au(1)‚‚‚H(10A) interaction (3.072
Å). For 4, the nearest intermolecular contact is at-
tributed to the hydrogen-bonding interaction between
O(1) and H(49A) on C(49) of the phenyl ring (O(1)‚‚‚
H(49A) ) 2.399 Å), and an intermolecular Au(1)‚‚‚
H(17A) interaction (3.004 Å) is also observed. Although
the fluorenyl ring system is almost planar in 2 and 4
(mean deviations 0.024 and 0.014 Å, respectively), no
indication of the presence of π-stacking of the aromatic
rings is apparent. The CtC bond distances of 1.192(8)
Å (2) and 1.20(2) Å (4) are characteristic of terminal
acetylides. Variation of the fluorenyl group does not
have a significant influence on the bonding in the
central PAuCtC unit. The average Au-P bond lengths
of 2.276(1) Å in 2 and 2.275(3) Å in 4 are similar to those
observed in other alkynylgold(I) phosphines3a,c,d,6 but
longer than those of the chlorogold(I) phosphine com-
plexes,17 in line with the higher trans influence of the
alkynyl group. The Au-C bond distances lie in the
narrow range 1.985(6)-2.022(9) Å. The geometry about
the Au(I) center is essentially linear, and the mean
P-Au-C angles of 176.5(2)° (2) and 172.8(4)° (4) and
Au-C-C angles of 174.2(6)° (2) and 166(1)° (4) are
indicative of sp hybridization in Au(I) and acetylenic
carbon necessary for a rigid-rod molecule. However, we
observe a slight bending of the AuPPh3 fragments away
from the mean plane of the diacetylenic fluorene moiety
in the structure of 4, presumably due to crystal-packing
effects, and the distances of Au(1) and Au(2) from the
mean plane are -0.858 and 0.651 Å, respectively. All
of these structural parameters are comparable to those
found for other crystal structures of mononuclear,
binuclear, and oligomeric alkynylgold(I) complexes.3a,c,d,6
The molecular structure of 11 is depicted in Figure
3, and some important bond distances and angles are
given in Table 3. The crystal structure shows a binuclear
molecule in which two MeHgII units are linked by a
diacetylenic fluoren-9-one-2,7-diyl moiety in a rigid-rod
manner. This is the first example of a dimercury(II)
diacetylide complex to be characterized crystallographi-
cally. Reported structures of mononuclear Hg(II) acetyl-
ides are also limited.18 There are no apparent short
intermolecular interactions between the fluorenyl rings
(17) (a) Angermaier, K.; Zeller, E.; Schmidbaur, H. J . Organomet.
Chem. 1994, 472, 371. (b) Assefa, Z.; McBurnett, B. G.; Stables, R. J .;
Fackler, J . P., J r.; Assmann, B.; Angermaier, K.; Schmidhaur, H. Inorg.
Chem. 1995, 34, 75. (c) Mu¨ller, T. E.; Green, J . C.; Mingos, D. M. P.;
McPartlin, C. M.; Whittingham, C.; Williams, D. J .; Woodroffe, T. M.
J . Organomet. Chem. 1998, 551, 313.

5450 Organometallics, Vol. 20, No. 25, 2001
Wong et al.
F igu r e 3. Perspective drawing of compound 11.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 11
the HOMO-LUMO gap substantially by 1.51 eV. For
each spacer unit, there is a sequential lowering in the
energy gap from the ligand to the Hg(II) complex and
the Au(I) counterpart, indicative of the metal to ligand
π back-bonding, and the stronger interaction at the gold
center with a +1 formal oxidation state gives a smaller
optical gap. This agrees with the molecular orbital
calculations on 2, 4, and 11. Figure 4 depicts the contour
plots19 of the HOMO and LUMO for 4, showing the
common bonding feature in the frontier molecular
orbitals of these three complexes. The calculated HOMO-
LUMO gap follows the order 2 > 11 > 4, consistent with
the experimental observations (Table 4). It is obvious
that the LUMO has π* character involving the carbonyl
unit. By virtue of the accessible low-lying π* orbitals of
CO, the fluorenone-based organometallic complexes give
smaller energy gaps. We expect that metal fragments
at both ends of 4 and 11 affect more the HOMO and
less the LUMO. Indeed, the LUMOs of 4 and 11 are
similar in energy (-0.079 04 and -0.080 55 au, respec-
tively). Because of the greater electronegativity and
higher formal oxidation state, Hg(II) in 11 pulls down
the HOMO’s orbital energy more significantly when
compared to Au(I), leading to a larger HOMO-LUMO
gap.
With reference to spectroscopic studies on [Me3-
PAuCtCRCtCAuPMe3] (R ) C6H4, C6H2Me2) and
other similar alkynylgold(I) complexes, we can tenta-
tively assign the emissive bands to triplet π-π* or
triplet σ-π* excited states or a combination of both
associated with the metal acetylide groups.3 At 290 K,
the emission energies of the complexes roughly follow
the same order as the absorption maxima. Within each
metal class, the emission energy was found to change
upon variation of both the fluorene moieties R and the
auxiliary groups L and R′. Figure 5 shows the solution
emission spectra of IV, 4, and 12 at 290 K. Their similar
spectral patterns are suggestive of the ligand-dominat-
ing emissive state, and the spectra display featureless
luminescence peaks centered at ca. 531, 575, and 543
nm, respectively. We attribute the bathochromic shift
to an increased delocalization of π electrons into the
aromatic segment by virtue of the metal to ligand π
back-bonding interaction in the presence of filled metal
d orbitals, leading to a stabilization of the first π* orbital
of the acetylide groups.2c,3a,c The more marked effect for
Au(I) is consistent with the lower oxidation state of +1
in 4, which would enhance the back-donation to π*. The
same trend is observed for other complexes. The emis-
Hg(1)-C(15)
Hg(2)-C(17)
C(14)-C(15)
C(16)-C(17)
2.03(1)
2.05(2)
1.19(2)
1.16(2)
Hg(1)-C(18)
Hg(2)-C(19)
C(4)-C(14)
C(11)-C(16)
2.06(2)
2.06(2)
1.42(2)
1.46(2)
C(15)-Hg(1)-C(18) 178.0(7) Hg(1)-C(15)-C(14) 170(1)
C(4)-C(14)-C(15)
175(1)
C(17)-Hg(2)-C(19) 176.5(8)
C(11)-C(16)-C(17) 177(2)
Hg(2)-C(17)-C(16) 171(1)
as well as the Hg(II) centers. The Hg-C(alkyne) bond
(Hg(1)-C(15) ) 2.03(1) Å, Hg(2)-C(17) ) 2.05(2) Å) is
slightly longer than the Au-C(alkyne) bond in 4 but
comparable to those in other Hg(II) acetylide com-
pounds.18 The fluorenonediyl unit does not deviate
significantly from planarity, and the CtC bonds in the
ethynyl bridge are fairly typical at 1.19(2) and 1.16(2)
Å. Reminiscent of the PAuCtC fragment, the isoelec-
tronic MeHgCtC entity displays similar structural
motifs and geometry in 11. The angles C-Hg-C (C(15)-
Hg(1)-C(18) ) 178.0(7)°, C(17)-Hg(2)-C(19) ) 176.5-
(8)°) and Hg-C-C (Hg(1)-C(15)-C(14) ) 170(1)°,
Hg(2)-C(17)-C(16) ) 171(1)°) are close to linearity. The
Hg-CH3 bond (2.06(2) Å) is slightly shorter than those
observed in some methylmercury(II) complexes with
thiol ligands such as [(MeHg)2(S2C6H10)] (2.08(2)-2.12-
(2) Å)10b and [MeC(CH2SHgMe)3] (2.09(3)-2.13(3) Å).10c
Absor p tion a n d Em ission P r op er ties. The elec-
tronic absorption and emission data of our compounds
in CH2Cl2 are presented in Table 4. The absorption
spectra of the digold(I) and dimercury(II) complexes
display intense ligand-localized π f π* transitions in
the near-UV region (ca. 231-389 nm) and, in most
cases, at the low-energy regime of the visible spectrum
(ca. 422-579 nm). We note that the absorption bands
show bathochromic shifts when the d10 metal fragments
are introduced at the terminal groups, and the red shift
is more pronounced with the gold(I) species. These
observations are consistent with the increased π-delo-
calization through the metal groups due to metal to
ligand back-donation to π*(CtCR).2c,3a In this study, the
energy gap between the highest occupied (HOMO) and
lowest unoccupied (LUMO) molecular orbitals follows
the order 1 > 2 > 3 > 4 ≈ 5 ≈ 6 > 7 and 8 > 9 > 10 >
11 ≈ 12. Replacing the unsubstituted fluorene spacer
as in 1 by a 9-(dicyanomethylene)fluorene unit lowers
(18) (a) Gutierrez-Puebla, E.; Vegas, A.; Garcia-Blanco, S. Cryst.
Struct. Commun. 1979, 8, 861. (b) Gutierrez-Puebla, E.; Vegas, A.;
Garcia-Blanco, S. Acta Crystallogr., Sect. B 1978, 34, 3382. (c) Hoskins,
B. F.; Robson, R.; Sutherland, E. E. J . Organomet. Chem. 1996, 515,
259. (d) Hartbaum, C.; Roth, G.; Fischer, H. Eur. J . Inorg. Chem. 1998,
191. (e) Ghosh, I.; Mishra, R.; Poddar, D.; Mukherjee, A. K. Chem.
Commun. 1996, 435.
(19) Schaftenaar, G. Molden, version 3.5; CAOS/CAMM Center
Nijmegen, Toernooiveld, Nijmegen, The Netherlands, 1999.

Au(I) and Hg(II) Derivatives of Diethynylfluorenes
Organometallics, Vol. 20, No. 25, 2001 5451
Ta ble 4. Electr on ic Absor p tion a n d Em ission Da ta for Com p ou n d s 1-12 a n d Th eir F r ee Alk yn es
emissionc
energy gapb/
complex
absorptiona λmax/nm (ꢀ/104 dm3 mol-1 cm-1
242 (4.4), 325 (4.4), 360 (2.6)
)
eV
medium(T/K)
λmax/nm
1
3.35
solid (290)
solid (11)
583
551, 592
2
3
4
275 (1.2), 307 sh (2.3),
319 (4.4), 343 (9.7), 359 (9.0)
236 (4.8), 276 (2.4), 339 (3.5), 355 (4.7), 422 sh (0.5)
3.28
2.82
2.34
solid (290)
solid (11)
solid (290)
solid (11)
CH2Cl2 (290)
solid (290)
solid (11)
CH2Cl2 (290)
solid (290)
solid (11)
567
549, 597
vw
vw
575
589
590
583
628
633
577
596
239 (4.3), 291 (4.3), 337 (3.8), 355 (2.3), 458 (0.3)
295 (5.8), 336 (4.0), 351 (4.1), 461 (0.4)
5
6
2.35
2.36
268 (1.2), 301 (1.3), 338 (0.7), 354 (1.0), 389 (0.3), 409 (0.2), 465 (0.1)
CH2Cl2 (290)
solid (290)
solid (11)
604
7
8
236 (11.9), 268 (2.7), 276 (2.8), 323 (17.9), 351 sh (9.9), 579 (0.2)
231 (1.5), 258 sh (0.5), 311 (3.0), 344sh (2.3)
1.84
3.52
3.45
2.82
2.50
solid (290)
solid (11)
solid (290)
solid (11)
solid (290)
solid (11)
solid (290)
solid (11)
736
737
567
564
9
296 sh (2.0), 311 (4.0), 330 (6.4), 346 (8.2)
444, 457, 548 sh
444, 457, 555
vw
vw
555
597
599
10
11
238 (3.0), 286 (3.3), 326 (3.3), 460 sh (0.3)
292 (3.4), 315 (1.3), 329 (2.0), 336 (1.4), 343 (2.1), 439 (0.2)
CH2Cl2 (290)
solid (290)
solid (11)
12
231 (2.2), 286 (3.9), 315 (1.9), 329 (2.6), 337 (2.1), 343 (2.4), 437 (0.4)
2.48
CH2Cl2 (290)
solid (290)
solid (11)
543
587
590
I
II
III
IV
314 (1.2), 319 (1.1), 324 (1.1), 327 (1.2)
3.54
3.67
2.88
2.59
solid (290)
solid (290)d
solid (290)
CH2Cl2 (290)
solid (290)
solid (290)
429 sh, 505
492
vw
531
555
291 (3.3), 302 (4.7), 316 (4.0), 323 sh (3.8), 330 (7.1)
236 (4.3), 276 (4.5), 316 (3.6), 328 (4.2), 357 (1.8)
283 (4.4), 308 (1.7), 321 (2.3), 334 (1.6), 421 (0.2)
V
296 (2.5), 325 (1.8), 347 (1.5), 364 (1.2), 505 (0.1)
2.10
562
a
b
All absorption spectra were recorded in CH2Cl2 at 290 K. Abbreviations: sh ) shoulder. vw ) very weak. Estimated from the onset
of absorption. c Excitation wavelength is 325 nm. Sample as a thin film was used.
d
F igu r e 4. Spatial plots of the highest occupied (HOMO)
and the lowest unoccupied molecular orbitals (LUMO) for
H3PAuCtCRCtCAuPH3 (R ) fluoren-9-one-2,7-diyl).
F igu r e 5. Emission spectra for IV (dotted line), 4 (solid
line), and 12 (dashed line) in CH2Cl2 solutions.
sion wavelengths of fluorenone-linked complexes are
longer than those of their fluorene analogues because
of the higher degree of π-conjugation of the fluorenone
unit. The emission of 5 is also red-shifted relative to 4.
This can be rationalized by the fact that the PMe3 ligand
is electron-donating in nature, which renders the Au(I)
center more electron-rich. We observe that the order of
emission energies is 4 > 6 > 5, which is in line with
the σ-donating ability of the phosphines: i.e., PMe3 >
PAnPh2 > PPh3. Similarly, the order of emission ener-
gies 12 > 11 is expected on the basis of the different
σ-donating capacities of the hydrocarbyl groups, i.e., Me
> Ph.
Electr och em istr y. The redox data for electroactive
complexes in CH2Cl2 are summarized in Table 5. Each
of the cyclic voltammograms of 3 and 10 displays one
quasi-reversible ferrocenyl oxidation couple with the
half-wave potential in the order 10 > 3 > III. This is in
accord with the unsaturation of the organometallic end-
capped ethynyl bridges, which would render the ferro-
cenyl center less electron-rich. The E1/2 value is sub-
stantially more anodic in 10 than in 3 because of the

5452 Organometallics, Vol. 20, No. 25, 2001
Wong et al.
Ta ble 5. Red ox Da ta for Electr oa ctive Com p ou n d s
a n d Th eir Liga n d P r ecu r sor s
wise stated, were obtained from commercial sources and used
as received. Preparative TLC was performed on 0.7 mm silica
plates (Merck Kieselgel 60 GF254) prepared in our laboratory.
The starting materials 4-ferrocenylbenzaldehyde,14 2,7-bis-
((trimethylsilyl)ethynyl)fluorene,12a 2,7-diethynylfluorene (I),12a
2,7-bis(trimethylethynyl)fluoren-9-one,12a 2,7-diethynylfluoren-
9-one (IV),12a and AuCl(PAnPh2)17c were prepared by literature
methods. Infrared spectra were recorded as KBr pellets using
a Perkin-Elmer Paragon 1000 PC or Nicolet Magna 550 Series
II FTIR spectrometer. NMR spectra were measured in ap-
propriate solvents on a J EOL EX270 or a Varian INOVA 400
MHz FT-NMR spectrometer, with 1H NMR chemical shifts
quoted relative to TMS and 31P chemical shifts relative to an
85% H3PO4 external standard. Electron impact (EI) and fast
atom bombardment (FAB) mass spectra were recorded on a
Finnigan MAT SSQ710 mass spectrometer. Electronic absorp-
tion spectra were obtained with a Hewlett-Packard 8453 UV-
vis spectrometer. For emission spectra measurement, the 325
nm line of a He-Cd laser was used as an excitation source.
The luminescence spectra were analyzed by a 0.25 m focal
length double monochromator with a Peltier cooled photomul-
tiplier tube and processed with a lock-in amplifier. For low-
E1/2/V
compd (∆E/mV)
E1/2/V
compd (∆E/mV)
E
red/V
Ered/V
3
4
5
6
7
0.03 (160)
11
12
III
IV
V
-1.64
-1.61
-1.70
-1.68
0.02 (115)
-1.57a
-1.12, -1.75
-1.55
-1.02, -1.65
10
0.10 (108)
a
Irreversible wave.
higher formal oxidation state of mercury(II) than that
of gold(I). For 4, 5, 11, and 12, a quasi-reversible
reduction wave is observed in each case (-1.61 to -1.70
V), which is assigned as the fluorenone-centered reduc-
tion. The observation of a less cathodic potential in the
free alkyne IV is a manifestation of a more π delocalized
system in the Au(I) and Hg(II) complexes, and the
reduction potentials are more negative for Au(I) species
than for the Hg(II) counterparts. Variation of the PR3
ligands in the Au(I) compounds or changing the alkyl
by an aryl group in the Hg(II) complexes incurs a slight
shift in the reduction potentials, in agreement with the
absorption and emission data. The good σ-donating
PMe3 groups enhance the σ(P-Au) back-donation to π*
in 5, which leads to a slight positive shift of 0.02 V as
compared to the relatively π-accepting PPh3 ligands.
Likewise, the purely σ-donating Me group in 11 makes
the reduction potential of 11 appear at a more negative
value. Complex 6, however, only underwent an irrevers-
ible ligand-based reduction event at -1.57 V. Two
reversible reduction waves, attributable to the central
9-(dicyanomethylene)fluorene unit,20 are noted for 7,
and they occur at potentials more cathodic than those
of the diethynyl ligand V.
temperature measurements, samples were mounted in
a
closed-cycle cryostat (Oxford CC1104) in which the tempera-
ture can be adjusted from 10 to 330 K. Cyclic voltammetry
experiments were done with a Princeton Applied Research
(PAR) Model 273A potentiostat. A conventional three-electrode
configuration consisting of a glassy-carbon working electrode
and a Pt wire as the counter and reference electrodes was used.
The solvent in all measurements was deoxygenated CH2Cl2,
and the supporting electrolyte was 0.1 M [Bu4N]PF6. Ferrocene
was added as a calibrant after each set of measurements, and
all potentials reported were quoted with reference to the
ferrocene-ferrocenium couple. Density functional calculations
at the B3LYP level21 were performed on 2, 4, and 11 on the
basis of their experimentally determined geometries obtained
from crystallographic data. The basis set used for C, O, and
H atoms was 6-31G,22 while effective core potentials with a
LanL2DZ basis set23 were employed for P, Au, and Hg atoms.
The Gaussian 98 program was used for the calculations.24
Polarization functions were added for P (êd(P) ) 0.34). For
theoretical simplicity, PH3 was used to replace PPh3 in the
calculations. The hexyl groups were also replaced by H atoms.
Caution! Organomercurials are extremely toxic, and all ex-
perimentation involving these reagents should be carried out
in a well-vented hood.
Con clu d in g Rem a r k s
Our present work has demonstrated the versatility
of preparing a new family of luminescent binuclear gold-
(I) and mercury(II) bis(alkynyl) complexes showing
adjustable electronic and optical properties by insertion
of different peripheral substituents on the central
fluorene spacer units. The results have shown that
electronic absorption and emission spectral features of
these compounds extend over a wide range and can be
varied by modifying the 9-substituent of the fluorenyl
ring system and the metal center as well as their
auxiliary ligands. The empirical trends observed indi-
cate that delocalization of π electrons prevails over the
molecule and metal to ligand π back-donation is more
significant for the Au(I) complexes than the Hg(II)
congeners. Work is in progress to investigate oligomeric
and polymeric alkynylmercury(II) materials and sub-
sequently compare them with the gold(I) systems.
[P h 3P Au CtCRCtCAu P P h 3] (R ) F lu or en e-2,7-d iyl; 1).
AuCl(PPh3) (19.8 mg, 0.04 mmol) in MeOH (15 mL) was mixed
with 2,7-diethynylfluorene (I; 4.3 mg, 0.02 mmol) in THF (5
mL). To this solution mixture was added 2 mL of basic MeOH
(0.40 mmol, prepared by dissolving 0.20 g of NaOH in 25 mL
of MeOH). Within a few minutes, a light yellow solid precipi-
tated from the homogeneous solution. The solid was then
collected by filtration after stirring for 2 h, washed with MeOH,
and air-dried to furnish 1 in 95% yield (21.5 mg). IR (KBr):
(21) (a) Becke, A. D. J . Chem. Phys. 1993, 98, 5648. (b) Miehlich,
B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett. 1989, 157, 200.
(c) Lee, C.; Yang, W.; Parr, G. Phys. Rev. B 1988, 37, 785.
(22) Hariharan, P. C.; Pople, J . A. Theor. Chim. Acta 1973, 28, 213.
(23) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 299.
(24) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.,
J r.; Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.;
Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo,
C.; Clifford, S.; Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J . B.; Cioslowski, J .; Ortiz, J . V.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.;
Fox, D. J .; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.;
Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; J ohnson, B. G.; Chen,
W.; Wong, M. W.; Andres, J . L.; Head-Gordon, M.; Replogle, E. S.;
Pople, J . A. Gaussian 98, revision A.7; Gaussian, Inc.: Pittsburgh, PA,
1998.
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
a nitrogen atmosphere with the use of standard Schlenk
techniques, but no special precautions were taken to exclude
oxygen during workup. Solvents were predried and distilled
from appropriate drying agents. All chemicals, unless other-
(20) J ustin Thomas, K. R.; Lin, J . T.; Wen, Y. S. J . Organomet.
Chem. 1999, 575, 301.

Au(I) and Hg(II) Derivatives of Diethynylfluorenes
Organometallics, Vol. 20, No. 25, 2001 5453
ν(CtC) 2095 cm-1
.
1H NMR (CDCl3): δ 7.65-7.45 (m, 36H,
ν(CtN) 2224, ν(CtC) 2113 cm-1. 1H NMR (CDCl3): δ 8.46 (m,
2H, H1,8), 7.59-7.42 (m, 32H, H3,6 and Ph), 7.36 (d, J ) 7.8
Hz, 2H, H4,5). 31P NMR (CDCl3): δ 43.50. FAB-MS (m/z): 1192
[M+]. Anal. Calcd for C56H36Au2N2P2: C, 56.39; H, 3.04; N, 2.35.
Found: C, 56.15; H, 2.96; N, 2.25.
aromatic H), 3.81 (s, 2H, CH2). 31P NMR (CDCl3): δ 43.67.
FAB-MS (m/z): 1130 [M+]. Anal. Calcd for C53H38Au2P2: C,
56.30; H, 3.39. Found: C, 56.15; H, 3.30.
[P h 3P Au CtCRCtCAu P P h 3] (R ) 9,9-Dih exylflu or en e-
2,7-d iyl; 2). Complex 2 was synthesized using the same
conditions described above for 1, but 9,9-dihexyl-2,7-diethy-
nylfluorene (II; 7.7 mg, 0.02 mmol) was used instead to
produce a light yellow solid in 86% yield (22.3 mg). IR (KBr):
[MeHgCtCRCtCHgMe] (R ) F lu or en e-2,7-d iyl; 8). The
diyne I (8.6 mg, 0.04 mmol) in THF (5 mL) was first combined
with MeHgCl (20.1 mg, 0.08 mmol) in MeOH (15 mL), and
0.2 M basic MeOH (4 mL) was subsequently added to give a
pale yellow suspension. The solvents were then decanted, and
the light yellow solid of 8 (20.6 mg, 80%) was air-dried. IR
ν(CtC) 2099 cm-1 1H NMR (CDCl3): δ 7.59-7.43 (m, 36H,
.
aromatic H), 1.85 (m, 4H, CH2(CH2)4CH3), 1.05-0.88 (m, 12H,
CH2(CH2)3CH2CH3), 0.75 (t, J ) 7.2 Hz, 6H, (CH2)5CH3), 0.54
(m, 4H, CH2(CH2)3CH2CH3). 31P NMR (CDCl3): δ 43.74. FAB-
MS (m/z): 1299 [M+]. Anal. Calcd for C65H62Au2P2: C, 60.10;
H, 4.81. Found: C, 60.02; H, 4.64.
(KBr): ν(CtC) 2121 cm-1 1H NMR (CDCl3): δ 7.67 (d, J )
.
7.8 Hz, 2H, H3,6), 7.63 (s, 2H, H1,8), 7.49 (d, J ) 7.8 Hz, 2H,
2
H4,5), 3.87 (s, 2H, CH2), 0.72 (s, J HgH ) 148.5 Hz, 6H, Me).
FAB-MS (m/z): 643 [M+]. Anal. Calcd for C19H14Hg2: C, 35.46;
H, 2.19. Found: C, 35.35; H, 2.08.
[P h 3P Au CtCRCtCAu P P h 3] (R ) 9-((F er r ocen ylp h e-
n ylen e)m eth ylen e)flu or en e-2,7-d iyl; 3). According to the
same procedure described for the synthesis of 1, complex 3
was obtained from 9-((ferrocenylphenylene)methylene)-2,7-
diethynylfluorene (III; 9.7 mg, 0.02 mmol) as a red solid in
[MeHgCtCRCtCHgMe] (R ) 9,9-Dih exylflu or en e-2,7-
d iyl; 9). A procedure similar to that illustrated for 8 was used
to obtain the title compound in 90% yield (29.2 mg) from II
1
(15.3 mg, 0.04 mmol). IR (KBr): ν(CtC) 2124 cm-1. H NMR
(CDCl3): δ 7.57 (m, 2H, H1,8), 7.43 (m, 4H, H3,4,5,6), 1.92 (m,
4H, CH2(CH2)4CH3), 1.12-0.96 (m, 12H, CH2(CH2)3CH2CH3),
0.76 (t, J ) 7.2 Hz, 6H, (CH2)5CH3), 0.72 (s, 2J HgH ) 148.5 Hz,
6H, Me), 0.54 (m, 4H, CH2(CH2)3CH2CH3). FAB-MS (m/z): 811
[M+]. Anal. Calcd for C31H38Hg2: C, 45.86; H, 4.72. Found: C,
45.55; H, 4.50.
[MeHgCtCRCtCHgMe] (R ) 9-((F er r ocen ylp h en yle-
n e)m eth ylen e)flu or en e-2,7-d iyl; 10). Similar to 8, complex
10 was prepared from III (19.5 mg, 0.04 mmol) and isolated
as a deep orange solid in 95% yield (34.8 mg). IR (KBr): ν(Ct
C) 2129 cm-1. 1H NMR (CDCl3): δ 8.37 (m, 1H, H1 or H8), 7.88
(m, 1H, H1 or H8), 7.66-7.43 (m, 9H, C6H4, vinyl CH and
85% yield (23.9 mg). IR (KBr): ν(CtC) 2095 cm-1 1H NMR
.
(CDCl3): δ 7.92 (m, 1H, H1 or H8), 7.62-7.39 (m, 40H, C6H4,
vinyl CH, H3,4,5,6 and H1 or H8), 4.67 (t, J ) 1.8 Hz, 2H, Ha,a′),
4.28 (t, J ) 1.8 Hz, 2H, Hb,b′), 4.02 (s, 5H, C5H5). 31P NMR
(CDCl3): δ 43.70, 43.46. FAB-MS (m/z): 1402 [M+]. Anal.
Calcd for C70H50Au2FeP2: C, 59.93; H, 3.59. Found: C, 60.02;
H, 3.50.
[P h 3P Au CtCRCtCAu P P h 3] (R ) F lu or en -9-on e-2,7-
d iyl; 4). Compound 4 was prepared similarly from 2,7-
diethynylfluoren-9-one (IV; 4.6 mg, 0.02 mmol), and it was
isolated as a bright yellow solid in 86% yield (19.7 mg). IR
(KBr): ν(CtC) 2107, ν(CdO) 1717 cm-1. H NMR (CDCl3): δ
1
H
3,4,5,6), 4.74 (t, J ) 1.8 Hz, 2H, Ha,a′), 4.53 (t, J ) 1.8 Hz, 2H,
7.73 (s, 2H, H1,8), 7.59-7.41 (m, 32H, H3,6 and Ph), 7.34 (d, J
) 7.8 Hz, 2H, H4,5). 31P NMR (CDCl3): δ 43.55. FAB-MS (m/
z): 1144 [M+]. Anal. Calcd for C53H36Au2OP2: C, 55.61; H, 3.17.
Found: C, 55.58; H, 3.20.
2
Hb,b′), 4.23 (s, 5H, C5H5), 0.73 (s, J HgH ) 148.5 Hz, 3H, Me),
0.69 (s, J HgH ) 148.5 Hz, 3H, Me). FAB-MS (m/z): 916 [M+].
2
Anal. Calcd for C36H26FeHg2: C, 47.22; H, 2.86. Found: C,
47.02; H, 2.56.
[Me3P Au CtCRCtCAu P Me3] (R ) F lu or en -9-on e-2,7-
d iyl; 5). Addition of an excess of basic MeOH to a mixture of
AuCl(PMe3) (24.7 mg, 0.08 mmol) in MeOH and IV (9.1 mg,
0.04 mmol) in THF leads to the precipitation of 5 as an orange
powder in 80% yield (24.7 mg). IR (KBr): ν(CtC) 2100, ν(Cd
O) 1713 cm-1. 1H NMR (acetone-d6): δ 7.69 (m, 2H, H1,8), 7.55
(m, 2H, H3,6), 7.34 (d, J ) 7.7 Hz, 2H, H4,5), 1.56 (s, 9H, Me),
1.52 (s, 9H, Me). 31P NMR (CDCl3): δ 2.53. FAB-MS (m/z):
772 [M+]. Anal. Calcd for C23H24Au2OP2: C, 35.77; H, 3.13.
Found: C, 35.45; H, 3.02.
[MeHgCtCRCtCHgMe] (R ) F lu or en -9-on e-2,7-d iyl;
11). A procedure similar to that for 8 was employed using IV
(9.1 mg, 0.04 mmol) to produce bright orange 11 in 93% yield
(24.5 mg) after filtration and washing. IR (KBr): ν(CtC) 2127,
1
ν(CdO) 1712 cm-1. H NMR (CDCl3): δ 7.71 (d, J ) 1.2 Hz,
2H, H1,8), 7.57 (dd, J ) 1.2, 7.8 Hz, 2H, H3,6), 7.43 (d, J ) 7.8
Hz, 2H, H4,5), 0.73 (s, 2J HgH ) 148.5 Hz, 6H, Me). FAB-MS (m/
z): 657 [M+]. Anal. Calcd for C19H12Hg2O: C, 34.71; H, 1.84.
Found: C, 34.58; H, 1.90.
[P h HgCtCR CtCHgP h ] (R ) F lu or en -9-on e-2,7-d iyl;
12). Instead of using MeHgCl, the reaction between PhHgCl
(25.1 mg, 0.08 mmol) and IV (9.1 mg, 0.04 mmol) in basic
MeOH solution resulted in the precipitation of the desired
product 12 as a pale orange solid (27.5 mg, 88%). IR (KBr):
ν(CtC) 2130, ν(CdO) 1716 cm-1. 1H NMR (CDCl3): δ 7.77 (d,
J ) 1.2 Hz, 2H, H1,8), 7.63 (dd, J ) 1.2, 7.9 Hz, 2H, H3,6), 7.50-
7.30 (m, 12H, H4,5 and Ph). FAB-MS (m/z): 781 [M+]. Anal.
Calcd for C29H16Hg2O: C, 44.56; H, 2.06. Found: C, 44.58; H,
1.95.
Cr ysta llogr a p h y. Yellow crystals of 2, 4, and 11 suitable
for X-ray diffraction studies were grown by slow evaporation
of their respective solutions in hexane/CH2Cl2 at room tem-
perature. Geometric and intensity data were collected using
graphite-monochromated Mo KR radiation (λ ) 0.710 73 Å)
on a Bruker AXS SMART 1000 CCD area detector (2 and 4)
and MAR Research image plate scanner (11). The collected
frames were processed with the software SAINT,25a and an
absorption correction was applied (SADABS25b) to the collected
reflections. For 11 interframe scaling was employed for the
absorption correction.
[P h 2An P Au CtCRCtCAu P An P h 2] (R ) F lu or en -9-on e-
2,7-d iyl; 6). AuCl(PAnPh2) (23.8 mg, 0.04 mmol) and IV (4.6
mg, 0.02 mmol) were dissolved in CH2Cl2 separately before
mixing, and 2 mL of 0.2 M basic MeOH was then added to the
mixture. After this mixture was stirred at room temperature
for 2 h, the yellow precipitate was collected by filtration and
washed with MeOH to give 6 in 71% yield (19.1 mg). IR
1
(KBr): ν(CtC) 2099, ν(CdO) 1716 cm-1. H NMR (CDCl3): δ
8.70 (s, 2H, anthracenyl H), 8.32 (d, J ) 8.6 Hz, 4H, anthra-
cenyl H), 8.06 (d, J ) 8.6 Hz, 4H, anthracenyl H), 7.68-7.57
(m, 12H, H1,3,6,8 and anthracenyl H), 7.48-7.35 (m, 22H, H4,5
and Ph). 31P NMR (CDCl3): δ 28.24. FAB-MS (m/z): 1345 [M+].
Anal. Calcd for C69H44Au2OP2: C, 61.62; H, 3.30. Found: C,
61.50; H, 3.22.
[P h 3P Au CtCRCtCAu P P h 3] (R ) 9-(Dicya n om eth yl-
en e)flu or en e-2,7-d iyl; 7). To a mixture of AuCl(PPh3) (29.7
mg, 0.06 mmol) and 9-(dicyanomethylene)-2,7-diethynylfluo-
i
rene (V;12i 8.3 mg, 0.03 mmol) in Pr2NH/CH2Cl2 (20 mL, 1/1
v/v) was added CuI (1.0 mg). A dark blue suspension was
obtained within a short time, and the mixture was stirred at
room temperature for 15 h. The dark blue precipitate was
isolated by filtration and washed with MeOH. The crude solid
was then extracted with CH2Cl2 to afford an analytically pure
sample of 7 (20.0 mg, 56%) after solvent removal. IR (KBr):
(25) (a) SAINT Reference Manual; Siemens Energy and Automa-
tion: Madison, WI, 1994-1996. (b) Sheldrick, G. M. SADABS, Empiri-
cal Absorption Correction Program; University of Go¨ttingen, Go¨ttingen,
Germany, 1997.

5454 Organometallics, Vol. 20, No. 25, 2001
Wong et al.
Ta ble 6. Cr ysta l Da ta for Com p lexes 2·0.5C6H14, 4, a n d 11
2‚0.5C6H14
68H69Au2P2
4
11
C19H12Hg2O
empirical formula
fw
C
C53H36Au2OP2
1144.69
1342.10
657.48
cryst size, mm
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
0.32 × 0.15 × 0.10
triclinic
P1h
0.30 × 0.16 × 0.14
monoclinic
Pc
13.729(2)
11.503(1)
14.523(2)
0.34 × 0.14 × 0.12
monoclinic
P21/c
7.182(1)
16.414(1)
13.727(1)
9.1206(6)
16.970(1)
19.639(1)
96.399(1)
90.335(1)
101.956(1)
2954.0(3)
2
111.803(2)
98.38(1)
2129.5(4)
2
1.785
6.996
1100
1600.9(2)
4
2.728
19.204
1176
Z
D
calcd, g cm-3
1.509
5.054
1330
µ, mm-1
F(000)
temp, K
293
293
293
θ range, deg
1.52-27.49
1.77-27.52
1.00-25.59
min/max hkl
-5 to +11, -21 to +21, -25 to +24 -17 to +16, -14 to +13, -12 to +18 0-8, 0-19, -16 to +16
no. of rflns collected
no. of unique rflns (R(int))
no. of rflns with I > nσ(I)
no. of params
17 347
12 371
10 753
12 606 (0.0260)
12 606 (n ) 2.0)
638
R1 ) 0.0362
wR2 ) 0.0839
0.923 (on F2)
6645 (0.0402)
6645 (n ) 2.0)
524
R1 ) 0.0421
wR2 ) 0.0974
0.941 (on F2)
2.395 and -1.126
2836 (0.050)
1955 (n ) 1.5)
199
R ) 0.047
Rw ) 0.052
1.240 (on F)
1.14 and -2.10
final R indices (I > nσ(I))a
goodness of fit
largest diff peak and hole, e Å-3 1.287 and -0.640
R ) R1 ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑w(|Fo| - |Fc|)2/∑w(Fo)2]1/2. wR2 ) {∑[w(Fo - Fc2)2]/∑[w(Fo2)2]}1/2
.
a
2
The structures of these molecules were solved by direct
methods (SHELXTL26 for 2 and 4, SIR9227 for 11) in conjunc-
tion with standard difference Fourier techniques and subse-
quently refined by full-matrix least-squares analyses on F2 (for
2 and 4) and F (for 11). In each case, all non-hydrogen atoms
were assigned with anisotropic displacement parameters. The
hydrogen atoms were generated in their idealized positions
and allowed to ride on the respective carbon atoms. The
absolute configuration of 4 cannot be established successfully,
because racemic twinning is present. The highest residual
electron density peaks are all close to the heavy-atom positions.
Crystal data and other experimental details are summarized
in Table 6.
Ack n ow led gm en t. We thank the Hong Kong Re-
search Grants Council (Grant No. HKBU 2048/01P) and
the Hong Kong Baptist University (Grant No. FRG/99-
00/II-58) for financial support.
Su p p or tin g In for m a tion Ava ila ble: Text giving prepa-
rations of diethynylfluorene-based precursors, figures giving
emission spectra, and tables of X-ray crystal data for the
complexes. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM0106229
(27) Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick,
G. M., Kruger, C., Goddard, R. Eds.; Oxford University Press: London,
1985; p 175.
(26) Sheldrick, G. M. SHELXTL Reference Manual, version 5.1;
Siemens Energy and Automation: Madison, WI, 1997.