Organometallic complexes for nonlinear optics. Part 25. Quadratic and cubic hyperpolarizabilities of some dipolar and quadrupolar gold and ruthenium complexes

Article abstract of DOI:10.1016/S0022-328X(01)01281-5

The complexes [Au(4-CCC₆H₄NO₂)(L)] [L=PCy₃ (1), PMe₃ (2)], [(L)Au(μ-4-CCRCC)Au(L)] [R=C₆H₄, L=PCy₃ (4), PPh₃ (5); R=C₆H₄-4-C₆

Full text of DOI:10.1016/S0022-328X(01)01281-5

Journal of Organometallic Chemistry 642 (2002) 259–267
www.elsevier.com/locate/jorganchem
Organometallic complexes for nonlinear optics
Part 25. Quadratic and cubic hyperpolarizabilities of some dipolar
and quadrupolar gold and ruthenium complexesꢀ
Stephanie K. Hurst a, Marie P. Cifuentes a, Andrew M. McDonagh a,
Mark G. Humphrey a,*, Marek Samoc b, Barry Luther-Davies b, Inge Asselberghs c,
Andre´ Persoons c
a Department of Chemistry, Australian National Uni6ersity, Canberra, ACT 0200, Australia
b Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National Uni6ersity, Canberra, ACT 0200, Australia
c Laboratory of Chemical and Biological Dynamics, Centre for Research on Molecular Electronics and Photonics, Uni6ersity of Leu6en,
Celestijnenlaan 200D, B-3001 Leu6en, Belgium
Received 24 August 2001; received in revised form 19 September 2001; accepted 19 September 2001
Abstract
The complexes [Au(4-CꢀCC6H4NO2)(L)] [L=PCy3 (1), PMe3 (2)], [(L)Au(m-4-CꢀCRCꢀC)Au(L)] [R=C6H4, L=PCy3 (4),
PPh3 (5); R=C6H4-4-C6H4, L=PCy3 (7), PPh3 (8)], trans,trans-[RuCl(dppm)2(m-4,4%-CꢀCC6H4C6H4CꢀC)RuCl(dppm)2] (11),
trans-[Ru(X)(Y)(dppe)2] [X=Cl, Y=4-CꢀCC6H4I (12), 4-CꢀCC6H4CꢀCSiMe3 (13); X=CꢀCPh, 4-CꢀCC6H4CꢀCH (14)] and
{trans-[Ru(CꢀCPh)(dppe)2]}2(m-4,4%-CꢀCC6H4CꢀCCꢀCC6H4CꢀC) (15) have been prepared and their electrochemical (Ru com-
plexes) and nonlinear optical properties assessed. Electronic communication between the metal centers in 10, 11 and 15 diminishes
as the p-delocalizable bridge is lengthened. Quadratic nonlinear optical (NLO) merit increases on replacing triarylphosphine by
trialkylphosphine, the relative i values Au(4-CꢀCC6H4NO2)(PPh3)B1B3 being observed. Cubic NLO values are small for the
gold complexes and much larger for the ruthenium examples. Complex 15 has the largest |2/MWt (two-photon absorption
cross-section/molecular weight) value observed thus far for an organometallic complex. © 2002 Elsevier Science B.V. All rights
reserved.
Keywords: Ruthenium; Gold; Hyperpolarizability; Acetylide; Electrochemistry; Nonlinear optics
Ref. [6]. We report herein studies exploring the effect of
phosphine variation on quadratic NLO merit in a sys-
1. Introduction
tem for which resonance-enhancement is minimal and,
The nonlinear optical (NLO) properties of
therefore, for which a realistic evaluation of this struc-
organometallic complexes have come under consider-
tural variation is possible.
able scrutiny recently [2,3], alkynyl complexes in partic-
ular revealing large NLO responses. Gold acetylide
The great majority of studies examining the NLO
response of organometallics involve quadratic hyperpo-
complexes have good transparency characteristics
larizabilities; the limited studies of cubic NLO merit
(umaxB350 nm), and we have previously reported ex-
amples with significant i1064 and two-level corrected i0
coefficients [4,5]; a summary of studies of the NLO
have generally involved complexes with a donor–accep-
tor composition designed for enhanced quadratic re-
sponse, and for which a ‘cascade’ effect to enhance the
properties of gold complexes has appeared recently in
cubic NLO response is possible. Centrosymmetric com-
pounds, for which all i components are zero, and for
which a cascade effect is therefore not possible, are little
explored. We also report herein studies of a range of
centrosymmetric gold and ruthenium complexes, which,
ꢀ Part 24: see Ref. [1].
* Corresponding author. Tel.: +61-2-6125-2927; fax: +61-2-6125-
0760.
E-mail address: mark.humphrey@anu.edu.au (M.G. Humphrey).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01281-5

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S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
Scheme 1. Syntheses of 4-nitrophenylalkynylgold complexes 1–3.
Scheme 2. Syntheses of alkynylbis{(phosphine)gold} complexes 4–9.
for the latter, have resulted in complexes with extremely
large cubic NLO coefficients for organometallics. The
two-photon absorption (TPA) characteristics of
quadrupolar compounds have recently commanded at-
tention [7]; the present work also reports the first TPA
data for quadrupolar organometallic complexes.
bis{bis(diphenylphosphino)methane}ruthenium
com-
plex 11 was prepared by extending the method of
Touchard et al. [9] (Scheme 3); complex 10 has been
reported previously by Lewis and co-workers [10].
The centrosymmetric bis{bis(diphenylphosphino)-
ethane}ruthenium complex 15 was prepared according
to Scheme 4. Reaction of two equivalents of 4-
HCꢀCC6H4I with cis-[RuCl2(dppe)2] afforded trans-
2. Results and discussion
2.1. Synthesis and characterization of |-acetylide
complexes
The synthetic methodologies employed for the prepa-
ration of the new complexes are adaptations of those
successfully utilized for the preparation of the corre-
sponding phenylacetylide complexes. Gold nitropheny-
lacetylides 1 and 3 and gold phosphine complexes 4, 5,
7 and 8, which are binuclear complexes linked by
4-CꢀCC6H4CꢀC and 4,4%-CꢀCC6H4C6H4CꢀC ligands,
were prepared in good yield by extending the method of
Naulty et al. [5] (Schemes 1 and 2); complexes 6 and 9
have been reported recently by Puddephatt and co-
workers [8], while complex 2 was reported by us previ-
ously [4]. The (tricyclohexylphosphine)gold complexes
are significantly more soluble in common organic sol-
vents than their (triphenylphosphine)gold analogs, an
important factor when evaluating nonlinearities. The
Scheme 3. Syntheses of alkynyl bis[bis{bis(diphenylphosphino)-
methane}chlororuthenium] complexes 10 and 11.

S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
261
Scheme 4. Syntheses of complexes 12–15.
Table 1
Cyclic voltammetric data for ruthenium complexes 10, 11 and 15 a
Complex
E1/2 Ru(II)/(III) (V) DE1/2 (V) [ipc/ipa
]
Kcom
Reference
trans,trans-[RuCl(dppm)2(m-4,4%-CꢀCC6H4CꢀC)RuCl(dppm)2] (10)
0.22, 0.54
0.26, 0.56
0.41, 0.51
0.32
0.30
0.10
1.0, 1.0
1.0, 1.0
1.0, 1.0
2.6×105 This work
1.2×105 [10]
trans,trans-[RuCl(dppm)2(m-4,4%-CꢀCC6H4C6H4CꢀC)RuCl(dppm)2]
(11)
4.9×10
This work
{trans-[Ru(CꢀCPh)(dppe)2]}2(m-4,4%-CꢀCC6H4CꢀCCꢀCC6H4CꢀC)
(15)
0.58
0
1.0
0
This work
a Ferrocene/ferrocenium couple (0.56 V) as an internal standard.
bands in the range of 325–342 nm (gold complexes)
and 340–370 nm (ruthenium complexes), and the IR
spectra show characteristic coordinated w(CꢀC) bands
in the range of 2106–2115 cm−1 (gold complexes) and
2057–2077 cm−1 (ruthenium complexes), the spectrum
[Ru(4-CꢀCC6H4I)Cl(dppe)2] (12) after basic work-up.
The iodo substituent is amenable to Sonogashira cou-
pling; thus, the reaction of 12 with trimethylsily-
lacetylene in the presence of Pd(II) and Cu(I) catalysts
afforded
trans-[Ru(4-CꢀCC6H4CꢀCSiMe3)Cl(dppe)2]
of 13 also showing a free w(CꢀC) band at 2148 cm−1
.
(13). The reaction of 13 with phenylacetylene in the
presence of triethylamine gave trans-[Ru(4-CꢀCC6-
H4CꢀCSiMe3)(CꢀCPh)(dppe)2], subsequent removal of
the trimethylsilyl protecting group with fluoride afford-
ing trans-[Ru(4-CꢀCC6H4CꢀCH)(CꢀCPh)(dppe)2] (14).
Finally, oxidative coupling of 14 utilizing Pd(II)/Cu(I)
as catalysts gave {trans-[Ru(CꢀCPh)(dppe)2]}2(m-4,4%-
CꢀCC6H4CꢀCCꢀCC6H4CꢀC) (15).
31P-NMR spectra of all complexes contain one singlet
resonance, consistent with the trans geometry at the
ruthenium center and centrosymmetry in the binuclear
complexes.
2.2. Electrochemical studies
The new complexes were characterized by SI mass
spectrometry, satisfactory microanalyses, UV–vis, IR,
1H- and 31P-NMR spectroscopy. Mass spectra for the
gold complexes contain weak or nonexistent molecular
ion signals, (phosphine)gold units being the most abun-
dant ions observed. With the exception of 15, all ruthe-
nium complexes gave mass spectra with molecular ions
or protonated molecular ions. UV–vis spectra contain
The electrochemical data for the binuclear ruthenium
complexes 10, 11 and 15 are given in Table 1. Complex
10 was examined earlier by cyclic voltammetry [10]; the
data are also included in Table 1, and are experimen-
tally similar to data collected under our own experi-
mental conditions. This series of complexes is of
interest as it corresponds to a range of potentially
p-delocalizable bridging units coupling the two

262
S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
Introduction of acceptor nitro substituent in proceed-
ing from [Au(CꢀCPh)(PMe3)] to 3 leads to the expected
red-shift in umax and a significant increase in the
quadratic optical nonlinearity. Replacing the tri-
arylphosphine with trialkylphosphines in progressing
from 2 to 1 and 3 results in an increase in nonlinearity,
a result that contrasts with our earlier observation of a
similar ligand replacement in nitropyridylalkynyl com-
plexes. Trialkylphosphines are stronger donors than
triarylphosphines, whereas the latter provide additional
p-delocalization possibilities, and the relative impor-
tance of these two factors for quadratic NLO merit
appears to vary in proceeding from phenylalkynyl to
pyridylalkynyl complexes.
Ru(L2)2X groups (L2=dppm, dppe; X=Cl, CꢀCPh).
All Ru(II)/(III) couples listed in Table 1 are essentially
reversible, so an assessment of the electronic communi-
cation by considering the difference in Ru(II)/(III) cou-
ples (DE1/2) is appropriate. We have noted previously
that trans-disposed phenylalkynyl ligands behave elec-
tronically as pseudo-halides in complexes of this type
[11,12], so the progression in DE1/2 data should reflect
changes in the nature of the bridging unit. Several
studies assessing electronic communication between
metal centers in binuclear acetylide complexes have
been reported recently [10,13–16]; the present data
affords the possibility of assessing the effect of bridge
lengthening on electronic communication. Extending
the length of the p-delocalizable bridge in proceeding
from 10 to 11 and then 15 results in a decrease in
electronic communication, as assessed by DE1/2. The
comproportionation constants Kcom for these complexes
have been calculated and are listed in Table 1. Follow-
ing the Robin and Day classification [17], 15 is a Class
I binuclear complex, in which the metal centers are not
interacting, 11 is a borderline Class I/Class II example,
and 10 belongs to Class II, in which metal centers are
weakly interacting.
2.4. Cubic hyperpolarizabilities
Third-order nonlinearities for 1–4, 7, 10, 11 and 15
were determined by Z-scan at 800 nm, data being
collected in Table 3; complexes 5, 6, 8, and 9 were
insufficiently soluble in CH2Cl2 or THF to acquire
useful data. An electronic origin for cubic nonlinearities
in related metal acetylide complexes has been demon-
strated previously by degenerate four-wave mixing mea-
surements [19], and nonlinearities for the present series
of compounds are therefore likely to be electronic in
origin.
2.3. Quadratic hyperpolarizabilities
The effect on refractive nonlinearity kreal of phos-
phine ligand replacement in the dipolar series 1–3 is
negligible, all kreal data being equivalent within the error
margins; unlike 2, no detectable kimag component is
present for 1 and 3. The binuclear gold complexes 4
and 7 have very small cubic nonlinearities. Molecular
second hyperpolarizabilities for the binuclear ruthe-
nium complexes 10, 11 and 15 are significantly larger;
thus, replacing Au(PCy3) with trans-RuCl(dppm)2 in
proceeding from 4 to 10 or 7 to 11 results in a dramatic
increase in ꢀkꢀ. For the ruthenium complexes, negative
kreal and significant kimag components are consistent
with the presence of two-photon states contributing to
the observed nonlinearity. The present data for cen-
trosymmetric complexes complement our previously re-
We have determined the molecular quadratic nonlin-
earities of 1 and 3, using hyper-Rayleigh scattering at
1064 nm; the results of these studies, iexp, are given in
Table 2, together with the two-level-corrected values i0,
and the corresponding data for relevant complexes. We
have discussed previously the potential inadequacies of
the two-state model [18]. The low-energy band for these
complexes is MLCT in character; higher-energy bands
involve transitions with other ligands, which result in
little change in the dipole moment between ground and
excited states, and hence little contribution to nonlin-
earity; therefore it is probable that the two-level-cor-
rected values have some significance as an indicator of
zero-frequency nonlinearity.
Table 2
Experimental linear optical spectroscopic and quadratic nonlinear optical response parameters a
Compound
umax (nm) [m (104
M
−1 cm−1)]
iexp (10−30 esu) b
i0 (10−30 esu)
Reference
[Au(4-CꢀCC6H4NO2)(PCy3)] (1)
[Au(4-CꢀCC6H4NO2)(PPh3)] (2)
[Au(4-CꢀCC6H4NO2)(PMe3)] (3)
[Au(CꢀCPh)(PMe3)]
[Au(CꢀCC5H3N-2-NO2-5)(PPh3)]
[Au(CꢀCC5H3N-2-NO2-5)(PMe3)]
342 [2.2]
338 [2.5]
339 [1.3]
296 [1.3]
339 [2.6]
340 [1.6]
31
22
50
6
38
12
16
12
27
4
20
6
This work
[4]
This work
[4]
[5]
[5]
a All measurements in THF solvent. All complexes are optically transparent at 1064 nm; values 910%.
b HRS at 1064 nm corrected for resonance enhancement at 532 nm using the two-level model with i0=i[1-(2umax/1064)2][1−(umax/1064)2];
damping factors not included.

S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
263
Table 3
Experimental linear optical spectroscopic and cubic nonlinear optical response parameters a
Compound
umax (nm)
[m (104
M
kreal
(10−36 esu)
kimag
(10−36 esu)
ꢀkꢀ
Reference
(10−36 esu)
−1 cm−1)]
[Au(4-CꢀCC6H4NO2)(Pcy3)] (1)
[Au(4-CꢀCC6H4NO2)(PPh3)] (2)
[Au(4-CꢀCC6H4NO2)(Pme3)] (3)
[(PCy3)Au-4-CꢀCC6H4CꢀCAu(PCy3)] (4)
[(PCy3)Au-4,4%-CꢀCC6H4C6H4CꢀCAu(PCy3)] (7)
trans,trans-[RuCl(dppm)2(m-4,4%-CꢀCC6H4CꢀC)-
RuCl(dppm)2] (10)
342 [2.2]
338 [2.5]
339 [1.3]
325 [5.6]
324 [6.5]
354 [4.2]
100950
120940
150950
5250
−3009200
−32009500
–
100950
120940
150950
5250
3009200
35009600
This work
This work
This work
This work
This work
This work
20915
–
–
0930
14009300
trans,trans-[RuCl(dppm)2(m-4,4%-CꢀCC6H4-
C6H4CꢀC)RuCl(dppm)2] (11)
trans-[RuCl(4-CꢀCC6H4NO2)(dppm)2]
trans-[RuCl(4,4%-CꢀCC6H4C6H4NO2)(dppm)2]
{trans-[Ru(CꢀCPh)(dppe)2]}2(m-4,4%-CꢀCC6H4-
CꢀCCꢀCC6H4CꢀC) (15)
360 [9.0]
−11009300
300960
11009300
This work
466 [1.6]
448 [1.8]
438 [6.8]
170930
140930
−400091500
230950
64910
12 00092000
290960
150930
13 00092400
[33]
[33]
This work
a All measurements as THF solutions (all complexes are optically transparent at 800 nm). All results are referenced to silica, nonlinear refractive
index n2=3×10−16 cm2 W−1
.
ported data for dipolar complexes; replacing NO2 in the
dipolar examples with trans-[(CꢀC)RuCl(dppm)2] to af-
ford 10 or 11 results in significant increases in ꢀkꢀ, the
presence of the second electron-rich metal center being
more important than the dipolar composition in en-
hancing cubic NLO merit. These data suggest that
extending p-delocalization is the critical factor, consis-
tent with the experience with organic compounds. Sig-
nificant extension of the p-system, in proceeding from
10, 11 to 15, results in a further considerable increase in
ꢀkꢀ. Complex 15 has a very large kimag component. We
have reported earlier two-photon absorption cross-sec-
tions at 800 nm for a first-generation alkynylruthenium
dendrimer and its components [20]. Evaluating the TPA
cross-section |2 for 15 (2910×10−50 cm4 s) reveals that
it is similar in magnitude to that of the dendrimer
(4800×10−50 cm4 s); the |2/MWt is considerably
larger for 15 (1.3×10−50 cm4 s mol g−1) than for the
dendrimer (0.47×10−50 cm4 s mol g−1), and indeed is
the largest thus far for an organometallic complex.
assessed by cyclic voltammetry, the extent of which
diminishes as the p-bridge is lengthened. Cubic NLO
responses for the diruthenium complexes are large, with
evidence for two-photon effects contributing to the
observed responses at 800 nm. The ꢀkꢀ value for 15 is
very large, and its molecular weight-scaled two-photon
absorption cross-section is the largest reported thus far
for an organometallic complex, suggesting that similar
compounds may have potential in TPA applications.
4. Experimental
4.1. General conditions, reagents and instruments
All reactions were performed under a nitrogen atmo-
sphere with the use of standard Schlenk techniques
unless otherwise stated. Dichloromethane and Et3N
were dried by distilling over CaH2, Et2O and THF were
dried by distilling over sodium/benzophenone, and
other solvents were used as received. ‘Petroleum spirit’
refers to a fraction of petroleum ether of boiling range
60–80 °C. Chromatography was carried out in silica
gel (230–400 mesh ASTM) or basic ungraded alumina.
The following reagents were prepared by the litera-
ture procedures: [AuCl(PPh3)] [23], [AuCl(PMe3)] [24],
[AuCl(PCy3)] [25], 4-HCꢀCC6H4CꢀCH, 4,4%-HCꢀ
CC6H4C6H4CꢀCH and 4-HCꢀCC6H4NO2 [26], 4-
IC6H4CꢀCSiMe3 and 4-IC6H4CꢀCH [27], cis-[RuCl2-
(dppm)2] and cis-[RuCl2(dppe)2] [28]. Ferrocene
(Aldrich), Me3SiCꢀCH (Aldrich), PhCꢀCH (Aldrich),
[PdCl2(PPh3)2] (PMO), CuI (Aldrich), NH4PF6
(Aldrich), NaPF6 (Aldrich), tetramethylethylenediamine
(TMEDA) (Aldrich), tetra-n-butylammonium fluoride
(Aldrich), t-butyllithium (Aldrich) and 4-IC6H4CHO
(Karl Industries) were used as received.
3. Conclusions
The present studies have afforded a number of re-
sults. Nonlinearities for the dipolar gold complexes are
low compared with the related ruthenium complexes
reported earlier [5,18,21,22], although they have en-
hanced optical transparency; co-ligand replacement
does not have a clear-cut effect on quadratic nonlinear-
ity. Binuclear gold complexes have diminished solubil-
ity, which can be improved sufficiently to afford cubic
NLO data by employing PCy3; ꢀkꢀ values for these
digold complexes are uniformly low. Linked ruthenium
complexes can exhibit electronic communication, as

264
S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
4.2. Syntheses of metal complexes
EI (electron impact) mass spectra [both unit resolu-
tion and high resolution (HR)] were recorded using a
VG Autospec instrument (70 eV electron energy, 8 kV
accelerating potential) and secondary ion mass spectra
(SIMS) were recorded using a VG ZAB 2SEQ instru-
ment (30 kV Cs+ ions, current 1 mA, accelerating
potential 8 kV, 3-nitrobenzyl alcohol matrix) at the
Research School of Chemistry, Australian National
University; peaks are reported as m/z (assignment, rela-
tive intensity). Microanalyses were carried out at the
Research School of Chemistry, Australian National
University. Infrared spectra were recorded either as 1%
KBr discs or CH2Cl2 solutions using a Perkin–Elmer
System 2000 FTIR. 1H- and 31P-NMR spectra were
recorded using a Varian Gemini-300 FT NMR spec-
trometer and are referenced to residual CHCl3 (7.24
ppm), d-CHCl3 (77.0 ppm) or external 85% H3PO4 (0.0
ppm), respectively. The assignments follow the number-
ing scheme shown in Fig. 1. UV–vis spectra of solu-
tions were recorded in THF in 1 cm quartz cells using
a Cary 4 spectrophotometer. Electrochemical measure-
ments were recorded using a MacLab 400 interface and
MacLab potentiostat from ADInstruments. The sup-
porting electrolyte was 0.1 M (NnBu4)PF6 in distilled,
deoxygenated CH2Cl2. Solutions containing ca. 1×
10−3 M complex were maintained under Ar. Measure-
ments were carried out at room temperature (r.t.) using
platinum disc working-, Pt wire auxiliary- and Ag/AgCl
reference-electrodes, such that the ferrocene/ferroce-
nium redox couple was located at 0.56 V (peak separa-
tion around 0.09 V). Scan rates were typically 100
4.2.1. [Au(4-CꢀCC6H4NO2)(PCy3)] (1)
[AuCl(PCy3)] (200 mg, 0.39 mmol), 4-HCꢀCC6H4-
NO2 (69 mg, 0.47 mmol) and CuI (5 mg) were stirred in
a solution of CH3ONa in MeOH (0.1 M, 15 ml) for 12
h. Dichloromethane (100 ml) was added and the solu-
tion filtered through a plug of silica. The solvent was
removed under vacuum; the material was then tritu-
rated under petroleum spirit to yield 201 mg (82%) of
the pale-yellow product. Anal. Calc. for C26H37-
AuNO2P: C, 50.08; H, 5.98; N, 2.25. Found: C, 49.95;
H, 6.15; N, 2.05%. IR (cm−1, CH2Cl2): w(CꢀC) 2113.
UV–vis: u (nm) (m, M−1 cm−1) (THF): 342 (21 700).
1H-NMR (CDCl3, 300 MHz, l ppm): 1.10–2.10 (m,
33H, Cy), 7.55 (d, 2H, JHH=9 Hz, H4), 8.08 (d, 2H,
J
HH=9 Hz, H5). 31P-NMR (CDCl3, 121 MHz, l ppm):
56.8. SIMS; m/z: 1100 ([M+PCy3]+, 25), 624 ([M]+,
50), 477 [Au(PCy3)]+, 100).
4.2.2. [Au(4-CꢀCC6H4NO2)(PMe3)] (3)
[AuCl(PMe3)] (180 mg, 0.58 mmol) and 4-
HCꢀCC6H4NO2 (103 mg, 0.70 mmol) were stirred in a
solution of CH3ONa in MeOH (0.1 M, 15 ml) for 16 h.
After this time, a solid yellow product precipitated
which was collected by filtration. Yield 198 mg (81%).
Anal. Calc. for C11H13AuNO2P: C, 31.52; H, 3.13; N,
3.34. Found: C, 31.09; H, 3.21; N, 3.28%. IR (cm−1
,
)
CH2Cl2): w(CꢀC) 2115. UV–vis: u (nm) (m, M−1 cm−1
1
(THF): 339 (13 500). H-NMR (CDCl3, 300 MHz, l
ppm): 1.51 (m, 9H, Me), 7.52 (d, 2H, JHH=9 Hz, H4),
8.08 (d, 2H, JHH=9 Hz, H5). 31P-NMR (CDCl3, 121
MHz, l ppm): 1.4. SIMS; m/z: 349 ([Au(PMe3)2]+,
100), 273 ([Au(PMe3)]+, 25).
mV s−1
.
Fig. 1. Numbering scheme for NMR spectral assignments for 1–15.

S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
265
4.2.3. [(PCy3)Au(v-4-CꢀCC6H4CꢀC)Au(PCy3)] (4)
[AuCl(PCy3)] (200 mg, 0.39 mmol), 4-HCꢀCC6-
H4CꢀCH (24 mg, 0.19 mmol) and CuI (5 mg) were
stirred in a solution of CH3ONa in MeOH (0.1 M, 15
ml) for 12 h. Dichloromethane (100 ml) was added and
the solution filtered through a plug of silica. The sol-
vent was removed under vacuum to yield 183 mg (87%)
of the pale-yellow product. Anal. Calc. for C46H70-
Au2P2: C, 51.21; H, 6.54. Found: C, 51.30; H, 6.45%.
IR (cm−1, CH2Cl2): w(CꢀC) 2115. UV–vis: u (nm) (m,
Calc. for C52H38Au2P2: C, 55.83; H, 3.42%. Found: C,
54.87; H, 3.53%. IR (cm−1, CH2Cl2): w(CꢀC) 2106.
UV–vis: u (nm) (m, M−1 cm−1) (THF): 325 (65 600).
1H-NMR (CDCl3, 300 MHz, l ppm): 7.35–7.60 (m,
38H, Ph+C6H4). 31P-NMR (CDCl3, 121 MHz, l
ppm): 42.8. SIMS; m/z: 1119 ([M]+, 10), 757
([Au(PPh3)2]+, 35), 459 ([Au(PPh3)]+, 100).
4.2.7. trans,trans-[RuCl(dppm)2(v-4,4%-CꢀCC6H4C6-
H4CꢀC)RuCl(dppm)2]·H2O (11)
M
−1 cm−1) (THF): 325 (56 000), 306 (40 400). 1H-
cis-[RuCl2(dppm)2] (200 mg, 0.22 mmol), 4,4%-
HCꢀCC6H4C6H4CꢀCH (21 mg, 0.11 mmol) and
NH4PF6 (69 mg, 0.42 mmol) were heated in refluxing
CH2Cl2 (25 ml) for 9 h. The solution was filtered and
the solvent removed from the filtrate under reduced
pressure. The residue was triturated with Et2O and the
resultant solid was then redissolved in CH2Cl2. Triethy-
lamine (1 ml) was added with stirring and the solution
eluted through an alumina plug with CH2Cl2. Removal
of the solvent under reduced pressure yielded 145 mg
(68%) of the yellow product. Anal. Calc. for
C116H98OP8Ru2: C, 68.67; H, 4.87%. Found: C, 67.85;
H, 5.04%. IR (cm−1, CH2Cl2): w(CꢀC) 2077. UV–vis: u
(nm) (m, M−1 cm−1) (THF): 360 (90 400). 1H-NMR
(CDCl3, 300 MHz, l ppm): 1.55 (s, 2H, H2O), 4.90 (m,
8H, PCH2P), 6.10 (m, 4H, H4), 7.00–7.60 (m, 84H,
Ph+H5). 31P-NMR (CDCl3, 121 MHz, l ppm): −5.9.
SIMS; m/z: 2012 ([M+2H]+, 5), 905 ([RuCl(dppm)2]+,
85), 870 ([Ru(dppm)2]+, 100).
NMR (CDCl3, 300 MHz, l ppm): 1.20–2.00 (m, 66H,
Cy), 7.31 (s, 4H, C6H4). 31P-NMR (CDCl3, 121 MHz, l
ppm): 56.8. SIMS; m/z: 1079 ([M]+, 15), 757
([Au(PCy3)2]+, 100), 477 ([PCy3]+, 100).
4.2.4. [(PPh3)Au(v-4-CꢀCC6H4CꢀC)Au(PPh3)] (5)
[AuCl(PPh3)] (230 mg, 0.46 mmol), 4-HCꢀCC6H4-
CꢀCH (29 mg, 0.23 mmol) and CuI (5 mg) were stirred
in a solution of CH3ONa in MeOH (0.1 M, 15 ml) for
12 h. Dichloromethane (100 ml) was added and the
solution filtered through a plug of silica. The solvent
was removed under vacuum to yield 183 mg (87%) of
the pale-yellow product. Anal. Calc. for C46H34Au2P2:
C, 52.99; H, 3.29. Found: C, 52.46; H, 3.39%. IR
(cm−1, CH2Cl2): w(CꢀC) 2108. UV–vis: u (nm) (m,
M
−1 cm−1) (THF): 329 (53 800), 309 (37 700). 1H-
NMR (CDCl3, 300 MHz, l ppm): 7.36 (s, 4H, H4, H5),
7.40–7.60 (m, 30H, Ph). 31P-NMR (CDCl3, 121 MHz,
l ppm): 42.8. SIMS; m/z: 1042 ([M]+, 5), 721
([Au(PPh3)2]+, 10), 459 ([AuPPh3]+, 65).
4.2.8. trans-[Ru(4-CꢀCC6H4I)Cl(dppe)2] (12)
4.2.5. [(PCy3)Au(v-4,4%-CꢀCC6H4C6H4CꢀC)Au(PCy3)]
(7)
cis-[RuCl2(dppe)2] (500 mg, 0.52 mmol), 4-
HCꢀCC6H4I (240 mg, 1.05 mmol) and sodium hex-
afluorophosphate (200 mg, 1.19 mmol) were stirred in
CH2Cl2 (20 ml) for 6 h at r.t. Petroleum spirit (30 ml,
deoxygenated) was added via cannula and the total
solvent volume reduced to ꢀ25 ml in vacuo. The
mixture was filtered using Schlenk techniques and the
residue dissolved in CH2Cl2 (20 ml). Sodium methoxide
(65 mg, 1.19 mmol, in 2 ml of MeOH) was added to
deprotonate the vinylidene complex formed. The sol-
vent was removed in vacuo and the residue purified by
column chromatography, eluting with 4:1 CH2Cl2–
petroleum spirit. The product was precipitated by re-
moving the CH2Cl2 on a rotary evaporator. Upon
filtering, 480 mg of the yellow powder was isolated
(80%). Anal. Calc. for C60H52ClIP4Ru: C, 62.10; H,
4.52. Found: C, 62.34; H, 4.30%. UV–vis: u (nm) (m,
[AuCl(PCy3)] (200 mg, 0.39 mmol), 4,4%-HCꢀCC6H4-
C6H4CꢀCH (39 mg, 0.19 mmol) and CuI (5 mg, 0.03
mmol) were stirred in a solution of CH3ONa in MeOH
(0.1 M, 15 ml) for 16 h. The material was collected by
filtration, washed with MeOH and then with petroleum
spirit, affording 253 mg (56%) of the white product.
Anal. Calc. for C52H74Au2P2: C, 54.07; H, 6.46%.
Found: C, 53.33; H, 6.38%. IR (cm−1, CH2Cl2):
w(CꢀC) 2115. UV–vis: u (nm) (m, M−1 cm−1) (THF):
1
325 (56 000), 306 (40 400). H-NMR (CDCl3, 300 MHz,
l ppm): 1.20–2.00 (m, 66H, Cy), 7.31 (s, 4H, C6H4).
31P-NMR (CDCl3, 121 MHz, l ppm): 56.8. SIMS; m/z:
477 ([Au(PCy)3]+, 100).
4.2.6. [(PPh3)Au(v-4,4%-CꢀCC6H4C6H4CꢀC)Au(PPh3)]
(8)
M
−1 cm−1) (THF): 340 (24 500). IR (cm−1, CH2Cl2):
[AuCl(PPh3)] (150 mg, 0.30 mmol), 4,4%-HCꢀCC6H4-
C6H4CꢀCH (28 mg, 0.14 mmol) and CuI (5 mg) were
stirred in a solution of CH3ONa in MeOH (0.1 M, 15
ml) for 16 h. The material was collected by filtration,
washed with MeOH and then with petroleum spirit,
affording 118 mg (76%) of the white product. Anal.
w(CꢀC) 2068. 1H-NMR (CDCl3, 300 MHz, l ppm):
2.63 (m, 8H, CH2), 6.30 (d, JHH=8 Hz, 2H, H13),
6.90–7.44 (42H, Ph+H12). 31P-NMR (CDCl3, 121
MHz, l ppm): 50.1. SIMS; m/z: 1160 ([M]+, 17), 1125
([M−Cl]+, 32), 897 ([Ru(dppe)2]+, 23), 499
([Ru(dppe)]+, 16).

266
S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
4.2.9. trans-[Ru(4-CꢀCC6H4CꢀCSiMe3)Cl(dppe)2] (13)
trans-[Ru(4-CꢀCC6H4I)Cl(dppe)2] (12) (500 mg, 0.43
mmol) and trimethylsilylacetylene (180 ml, 1.27 mmol)
were dissolved in THF (15 ml). Dichlorobis(t-
riphenylphosphine)palladium(II) (10 mg, 0.014 mmol),
CuI (10 mg, 0.052 mmol) and Et3N (2 ml) were added
with stirring. The mixture was stirred for 20 min at r.t.
The solvent was then removed in vacuo and the residue
dissolved in CH2Cl2 and passed through an alumina
plug, eluting with CH2Cl2. Petroleum spirit was added
(ꢀ50 ml) and the solvent removed using a rotary
evaporator, affording 300 mg (62%) of the product as a
yellow powder. Anal. Calc. for C65H61ClP4RuSi: C,
69.05; H, 5.44. Found: C, 68.51; H, 5.50%. UV–vis: u
passed through an alumina plug. The solvent was re-
moved using a rotary evaporator and 54 mg (30%) of
the yellow powder was collected. Anal. Calc. for
C140H118P8O2Ru2: C, 73.67; H, 5.21. Found: C, 73.20;
H, 5.47%. UV–vis: u (nm) (m, M−1 cm−1) (THF): 438
1
(67 700). IR (cm−1, CH2Cl2): w(CꢀC) 2058. H-NMR
(CDCl3, 300 MHz, l ppm): 2.62 (m, 16H, CH2), 6.40–
7.60 (98H, Ph+H1+H12+H13). 31P-NMR (CDCl3,
121 MHz,
l
ppm): 54.4. SIMS; m/z: 999
([Ru(CꢀCPh)(dppe)2]+, 10), 898 ([Ru(dppe)2]+, 75).
4.3. Hyper-Rayleigh scattering measurements
An injection-seeded Nd:YAG laser (Q-switched
Nd:YAG Quanta Ray GCR5, 1064 nm, 8 ns pulses, 10
Hz) was focused into a cylindrical cell (7 ml) containing
the sample. The intensity of the incident beam was
varied by rotation of a half-wave plate placed between
crossed polarizers. Part of the laser pulse was sampled
by a photodiode to measure the vertically polarized
incident light intensity. The frequency doubled light
was collected by an efficient condenser system and
detected by a photomultiplier. The harmonic scattering
and linear scattering were distinguished by appropriate
filters; gated integrators were used to obtain intensities
of the incident and harmonic scattered light. The ab-
sence of a luminescence contribution to the harmonic
signal was confirmed by using interference filters at
different wavelengths near 532 nm. All measurements
were performed in THF using p-nitroaniline (i=
21.4×10−30 esu) [29] as a reference. Solutions were
sufficiently dilute such that the absorption of scattered
light was negligible. Further details on the experimental
procedure are reported in Refs. [30,31].
(nm) (m, M−1 cm−1) (THF): 370 (33 100). IR (cm−1
,
CH2Cl2): w(CꢀC) 2148, 2065. 1H-NMR (CDCl3, 300
MHz, l ppm): 0.24 (s, 9H, Me), 2.66 (m, 8H, CH2),
6.46 (d, JHH=8 Hz, 2H, H13), 6.87–7.40 (42H, Ph+
H12). 31P-NMR (CDCl3, 121 MHz, l ppm): 49.8. SIMS;
m/z: 1130 ([M]+, 100), 1095 ([M−Cl]+, 20), 897
([Ru(dppe)2−H]+, 25), 499 ([Ru(dppe)−H]+, 25).
4.2.10. trans-[Ru(4-CꢀCC6H4CꢀCH)(CꢀCPh)(dppe)2]
(14)
trans-[Ru(4-CꢀCC6H4CꢀCSiMe3)Cl(dppe)2] (13) (720
mg, 0.64 mmol), phenylacetylene (140 ml, 1.28 mmol),
sodium hexafluorophosphate (220 mg, 1.31 mmol) and
Et3N were stirred in CH2Cl2 for 4 h at r.t. The solvent
was then removed in vacuo and the residue purified by
column chromatography, eluting first with petroleum
spirit to remove excess acetylene, and then with 4:1
CH2Cl2–petroleum spirit to remove the yellow com-
plex. The solvent was removed, and the material was
then dissolved in CH2Cl2 (20 ml) and tetra-n-butylam-
monium fluoride (0.40 ml, 1 M solution in THF) was
added with stirring. The mixture was stirred for 30 min
at r.t. The solvent was then removed in vacuo and the
residue purified by column chromatography in alumina,
eluting with 2:3 CH2Cl2–petroleum spirit. The solvent
was removed using a rotary evaporator and 335 mg
(54%) of the yellow powder was collected. Anal. Calc.
for C70H58P4Ru: C, 74.79; H, 5.20. Found: C, 74.48; H,
5.20%. UV–vis: u (nm) (m, M−1 cm−1) (THF): 361
(35 400). IR (cm−1, CH2Cl2): w(CꢀC) 2057, w(CꢀCH)
4.4. Z-scan measurements
Measurements were performed at 800 nm using a
system consisting of a Coherent Mira Ar-pumped Ti-
sapphire laser generating a mode-locked train of ca. 100
fs pulses and a home-built Ti-sapphire regenerative
amplifier pumped with a frequency-doubled Q-switched
pulsed YAG laser (Spectra Physics GCR) at 30 Hz and
employing chirped pulse amplification. THF solutions
were examined in a glass cell with a 0.1 cm path length.
The Z-scans were recorded at two concentrations for
each compound and the real and imaginary part of the
nonlinear phase change determined by numerical fitting
[32]. The real and imaginary parts of the hyperpolariz-
ability of the solute were then calculated by assuming
linear concentration dependencies of the solution sus-
ceptibility. The nonlinearities and light intensities were
calibrated using measurements of a 1 mm thick silica
plate for which the nonlinear refractive index n2=3×
10−16 cm2 W−1 was assumed.
1
3294. H-NMR (CDCl3, 300 MHz, l ppm): 2.60 (m,
8H, CH2), 3.09 (s, 1H, CꢀCH), 6.58 (d, JHH=8 Hz,
2H, H12 or H13), 6.79 (d, JHH=8 Hz, 2H, H12 or H13),
6.89–7.59 (45H, Ph). 31P-NMR (CDCl3, 121 MHz, l
ppm): 54.5. SIMS; m/z: 1160 ([M]+, 17).
4.2.11. {trans-[Ru(CꢀCPh)(dppe)2]}2(v-4,4%-
CꢀCC6H4CꢀCCꢀCC6H4CꢀC)·2(H2O) (15)
trans-[Ru(4-CꢀCC6H4CꢀCH)(CꢀCPh)(dppe)2]
(14)
(180 mg, 0.16 mmol) was dissolved in CH2Cl2 (20 ml)
and PdCl2(PPh3)2 (8 mg) and CuI (4 mg) were added
with stirring. The solution was stirred for 6 h and then

S.K. Hurst et al. / Journal of Organometallic Chemistry 642 (2002) 259–267
267
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Acknowledgements
We thank the Australian Research Council
(M.G.H.), the Belgian Government (Grant No. IUAP-
PIV/11) (A.P.), the Fund for Scientific Research-Flan-
ders (G.0338.98, G.0407.98) (A.P.), the K.U. Leuven
(GOA/2000/03) (A.P.) for support of this work, and
Johnson-Matthey Technology Centre (M.G.H.) for the
generous loan of ruthenium salts. M.P.C. held an ARC
Australian Postdoctoral Research Fellowship, A.M.M.
held an Australian Postgraduate Award, and M.G.H.
holds an ARC Australian Senior Research Fellowship.
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