Synthesis, structural characterisation and photophysics of anionic cyclometalated bis(alkynyl)(benzo[h]quinolinate)platinate(II) species

Article abstract of DOI:10.1039/b210907g

The alkynylation of [Pt(bzq)(u-Cl)]₂ (bzqH = benzo[h]quinoline) with excess of LiC≡CR in diethyl ether leads to novel (7,8- benzoquinolinate)bis(alkynyl)platinate(II) monoanionic species [Pt(bzq)(C≡CR)₂]^- (R = ^tBu 1, SiMe ₃ 2, Ph 3, Tol 4, C₆H₄CF₃-4 5, C₅H₄N-2 6, C₆H₄-C≡CPh 7) which have been isolated as tetrabutylammoniun salts. The molecular X-ray structures of 3 and 6 reveal the presence of discrete anions with bond lengths and angles similar to those of related cyclometalated Pt compounds and no evidence of π-π or Pt-Pt stacking interactions. The influence of the R substituent on the photophysics of the complexes has been examined by UV-visible absorption, emission spectroscopy and cyclic voltammetry. Complexes 1-6 show a similar strong luminescence in both the solid state (structureless emission) and frozen solutions (well-resolved vibronic structures) while the emissions in solution at room temperature are red shifted (relative to the glass) and weak. For these complexes, on the basis of TD-DFT calculations which reproduce the experimental structure of anion 3, [Pt(bzq)(C≡CPh)₂]^-, the emissions are proposed to arise from mixed [π C≡CR/Pt d/π (bzq) → π* bzq] transitions. In contrast, complex 7 which contains the extended p-phenylethynylphenylacetylide ligand, C≡CC₆H ₄-C≡CPh, displays a structured emission both at 298 K and in glassy CH₂Cl₂ solutions. In this case the lack of a significant rigidochromism and DFT theoretical calculations support the involvement of a low-lying, metal perturbed acetylenic ³ππ * (C≡CC₆H₄-C≡CPh) excited state. The Royal Society of Chemistry 2003.

Full text of DOI:10.1039/b210907g

View Article Online / Journal Homepage / Table of Contents for this issue
Synthesis, structural characterisation and photophysics of anionic
cyclometalated bis(alkynyl)(benzo[h]quinolinate)platinate(II) species
Susana Fernández,a Juan Forniés,*b Belén Gil,a Julio Gómeza and Elena Lalinde*a
a Departamento de Química-Grupo de Síntesis Química de La Rioja, UA-CSIC,
Universidad de La Rioja, 26006, Logroño, Spain. E-mail: elena.lalinde@dq.unirioja.es
b Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón,
Universidad de Zaragoza-Consejo Superior de Investigaciones Científicas, 50009 Zaragoza,
Spain. E-mail: forniesj@posta.unizar.es
Received 6th November 2002, Accepted 23rd December 2002
First published as an Advance Article on the web 28th January 2003
᎐
The alkynylation of [Pt(bzq)(µ-Cl)] (bzqH = benzo[h]quinoline) with excess of LiC᎐CR in diethyl ether leads to
᎐
2
Ϫ
t
᎐
novel (7,8-benzoquinolinate)bis(alkynyl)platinate() monoanionic species [Pt(bzq)(C᎐CR) ] (R = Bu 1, SiMe 2,
Ph 3, Tol 4, C H CF -4 5, C H N-2 6, C H –C᎐CPh 7) which have been isolated as tetrabutylammoniun salts.
᎐
2
3
᎐
᎐
6
4
3
5
4
6
4
The molecular X-ray structures of 3 and 6 reveal the presence of discrete anions with bond lengths and angles
similar to those of related cyclometalated Pt compounds and no evidence of π–π or Pt–Pt stacking interactions.
The influence of the R substituent on the photophysics of the complexes has been examined by UV-visible
absorption, emission spectroscopy and cyclic voltammetry. Complexes 1–6 show a similar strong luminescence
in both the solid state (structureless emission) and frozen solutions (well-resolved vibronic structures) while the
emissions in solution at room temperature are red shifted (relative to the glass) and weak. For these complexes,
Ϫ
᎐
on the basis of TD-DFT calculations which reproduce the experimental structure of anion 3, [Pt(bzq)(C᎐CPh) ] ,
᎐
2
᎐
the emissions are proposed to arise from mixed [π C᎐CR/Pt d/π (bzq)
π* bzq] transitions. In contrast, complex
7 which contains the extended p-phenylethynylphenylacetylide ligand, C᎐CC H –C᎐CPh, displays a structured
᎐
᎐
᎐
᎐
᎐
6
4
emission both at 298 K and in glassy CH2Cl2 solutions. In this case the lack of a significant rigidochromism and DFT
3
᎐
᎐
theoretical calculations support the involvement of a low-lying, metal perturbed acetylenic ππ* (C᎐CC H –C᎐CPh)
᎐
᎐
6
4
excited state.
charge transfer by variation of the R substituent through the
Introduction
Pt–C᎐CR interaction;11–13 however, in some complexes, depend-
᎐
᎐
The chemistry of metal alkynyl complexes has long been the
subject of intense study mainly due to the versatile reactivity of
the unsaturated fragment and its wide variety of modes of
interaction with transition metals.1 Within this field the syn-
thesis of platinum acetylides has recently focused on the prep-
aration of specialty materials including non-linear optical,2
luminescent,3 liquid crystalline4 materials or the synthesis of
conjugated metal containing polymers.5 Platinum σ-acetylide
has also been employed as a building block for molecular
wires,6 macrocycles7 or hyperbranched8 and dendritic mole-
cules9 which are particularly attractive due to their potentially
useful redox, photophysical or catalytical properties. By far
the most work has been carried out with neutral trans- and
cis-platinum phosphine fragments.
The properties of platinum() complexes with chelate
diimine, terpyridyl or related cyclometalated ligands have
attracted considerable attention in recent years10 and, in this
context, a few systems containing alkynyl fragments have been
also prepared.11–13 These complexes usually exhibit long-lived
excited states mainly localized in the aromatic π systems which
are attractive for applications in chemical sensing, photo-
catalysis and in the development of supramolecular systems for
solar energy conversion. Additionally, for these square planar
d8 molecules, the axial positions are relatively open and vulner-
able to both nucleophilic attack and intermolecular Ptؒ ؒ ؒPt
stacking, facilitating exciplex quenching,10g,11a photoinduced
atom-transfer14 or excimer formation and excimer emission
when the excitation is delocalized through metal–metal interac-
tions.10k,15 The influence of non-covalent π–π ligand contacts on
the photoluminescence of this type of luminophores also has
many precedents.10e,k,16 It has also been shown that the nature
of the ancillary ligands can have marked effects on the lowest
emitting state. Thus, the incorporation of acetylide groups into
these systems usually tunes the energy of the emission attrib-
uted to a triplet metal-to-ligand (chelate aromatic π system)
ing on the nature of the R substituent, the photophysics are
derived from transitions between π and π* type orbitals largely
located on the aryl acetylide groups.11a,12a,c Despite considerable
progress in this area, most of the studies have focused on
neutral or cationic species and very little attention has been
devoted to exploring anionic systems.17
Recently, we have described the synthesis of homoleptic
Q [Pt(C᎐CR) ]18a,b and heteroleptic cis- and trans-Q2[Pt(C6F5)2-
᎐
᎐
2
᎐
4
t
18c–e
(C᎐CR) ] (R = Ph, Bu, SiMe )
dianionic alkynyl platinate
᎐
2
3
compounds and have shown that they are suitable precursors
for the preparation of homo and hetero (Pt–M, M = Cu(),
Ag(), Cd(), Hg(), Tl(), Rh(,) or Ir(,)) polynuclear com-
plexes stabilised by alkynyl and/or by Ptؒ ؒ ؒM bonding inter-
actions.19–20 A number of these complexes have been shown to
have luminescence properties that are associated with Ptؒ ؒ ؒPt,
Ptؒ ؒ ؒM and η2ؒ ؒ ؒM alkynyl bonding interactions.22 In view of
these results, we considered it worthwhile to prepare mono-
anionic bis(alkynide)cycloplatinate species of type [Pt(C∧N)-
Ϫ
᎐
(C᎐CR) ] in order to study their potential as precursors
᎐
2
of novel Pt–M (M = Tl, Cd or Hg) polynuclear complexes and
also gain further insights into the involvement of Ptؒ ؒ ؒM or
η2ؒ ؒ ؒM alkynyl contacts in the excited-state properties of
this type of cluster complexes. Here we describe the synthesis,
electronic absorption, luminescence and electrochemical prop-
erties of a series of bis(alkynyl)platinate compounds (NBu4)-
᎐
[Pt(bzq)(C᎐CR) ] (1–7) containing the planar orthometallated
᎐
2
7,8-benzoquinoline ligand (bzq).
Results and discussion
Synthesis and spectroscopic characterisation
The synthesis of the complexes is shown in Scheme 1. Treatment
of a yellow suspension of the dinuclear cycloplatinated chlor-
ide-bridged complex [Pt(bzq)(µ-Cl)]2 (bzqH = benzoquinoline
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
822

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Table 1 Selected bond lengths [Å] and angles [Њ] for (NBu4)[Pt(bzq)-
᎐
(C᎐CPh)2] 3
᎐
Pt(1)–C(1)
Pt(1)–N(1)
C(1)–C(2)
2.007(9)
2.065(8)
1.183(10)
Pt(1)–C(9)
Pt(1)–C(29)
C(9)–C(10)
1.985(11)
2.055(7)
1.188(12)
C(1)–Pt(1)–C(9)
C(9)–Pt(1)–N(1)
92.4(3)
94.1(4)
C(1)–Pt(1)–C(29)
C(29)–Pt(1)–N(1)
93.8(3)
79.7(3)
Table 2 Selected bond lengths [Å] and angles [Њ] for (NBu4)[Pt(bzq)-
᎐
(C᎐CC5H4N-2)2] 6 (molecules A and B)
᎐
Pt(1)–C(1)
Pt(1)–N(3)
C(1)–C(2)
1.976(6)
2.074(4)
1.205(7)
Pt(1)–C(8)
Pt(1)–C(25)
C(8)–C(9)
1.992(5)
2.050(4)
1.201(6)
C(1)–Pt(1)–C(8)
C(8)–Pt(1)–N(3)
93.74(19)
92.06(19)
C(1)–Pt(1)–C(25)
C(25)–Pt(1)–N(3)
93.65(18)
80.60(18)
Scheme 1
Pt(2)–C(28)
Pt(2)–N(6)
C(28)–C(29)
1.975(6)
2.063(4)
1.182(6)
Pt(2)–C(35)
Pt(2)–C(52)
C(35)–C(36)
1.975(5)
2.047(4)
1.209(6)
᎐
ligand) with an excess of LiC᎐CR in diethyl ether causes partial
᎐
or total dissolution of the initial yellow suspension, leading to
the formation of the anionic species [Pt(bzq)(C᎐CR) ] . These
Ϫ
᎐
᎐
2
C(35)–Pt(2)–C(28)
C(35)–Pt(2)–N(6)
93.74(19)
92.93(19)
C(28)–Pt(2)–C(52)
C(52)–Pt(2)–N(6)
92.44(18)
80.92(18)
anionic species, after usual work up by solvent removal, fol-
lowed by extraction with deoxygenated H2O or i-PrOH and
subsequent addition of NBu4Br (see Experimental for details)
By comparison the J(195Pt–13C) coupling to the cyclometal-
1
ϩ
can be crystallised as NBu4 salts in moderate to good yields
᎐
lated C atoms trans to alkynyl in complexes [Pt(C᎐CR)-
᎐
(32–83%). While neutral or cationic alkynyl cycloplatinated
compounds are known,11 to our knowledge these complexes
(1–7) are the first examples of anionic systems. We also noted
(NMe2NCH2(σ-Fc))(dmso)]11e and [Pt{η3-N,C,N-C3H3(CH᎐
᎐
11d
᎐
NR) -2,6}(C᎐CSiMe )] (R = 2,6-iPr C H ) was 790 and 616
᎐
2
3
2
6
3
Hz, respectively. For complexes 1–3 the expected two Cα and
two Cβ alkynyl carbons exhibit platinum satellites allowing
unambiguous assignment. In the three cases one of the Cα sig-
nals appears at rather high field [δ Cα (trans to N) 77.7 1; 119.24
2; 98.05 3] with respect to the other one [δ Cα (trans to C10)
110.95 1; 152.38 2; 123.8 3 (∆δ Cα 33.25 1, 33.14 2, 25.75 3)] and
exhibits the largest platinum coupling constant [1490 1; 1407 2;
1488 Hz 3 vs. 902 1; 895 Hz 2; not observed for 3], and is
therefore attributed to the alkynyl group located trans to the
iminic N atom. It is remarkable that the high frequency signal,
which is assigned to the Cα carbon atom located trans to the
ortometalated C10 atom, is shifted downfield (ca. 10 ppm) in
that whereas Robinson and coworkers,11e in the reaction of
᎐
[Pt{NCMe NCH (σ-Fc)}Cl(dmso)] and LiC᎐CPh, observed
᎐
2
2
facile reductive elimination giving rise to 1-dimethylamino-
methyl-2-phenylethynylferrocene, complexes 1–7 are thermally
stable in the solid state and in solution (at low temperature).
The new complexes 1–7 were obtained as bright yellow solids
and were fully characterized by elemental analysis, IR and
NMR (1H, 13C) spectroscopy, EI mass spectrometry as well as
single crystal X-ray crystallography for 3 and 6. All complexes
give the expected negative ion [M]Ϫ (100%) in their negative-ion
ES spectra and conductivity measurements in acetone confirm
their behaviour as 1 : 1 electrolytes. The IR spectra show two
=
t
᎐
relation to the homoleptic species [Pt(C᎐CR) ] species (R = Bu
Ϫ1
᎐
4
᎐
νC᎐C intense absorptions (2008–2108 cm ) consistent with a
᎐
98.9; SiMe3 140.4; Ph 120.9 ppm).22 The observed 1J(195Pt–13C)
cis configuration of the alkynyl ligands around the Pt() center.
For complex 7 one additional absorption is observed at 2209
cmϪ1 which is attributed to terminal free alkyne fragments. The
NMR data unambiguously reveal the presence of the 7,8-benzo-
quinolinate ligand and the existence of two inequivalent
alkynyl groups. A general labelling scheme for the inequivalent
bzq proton and carbon atoms is shown in Scheme 1. The NMR
data which were assigned on the basis of ligand spectra, the
presence of coupling constants and the results from two dimen-
coupling for this Cα carbon trans to C10 decreases slightly from
2Ϫ
᎐
those observed in the dianionic complexes [Pt(C᎐CR) ] (R =
᎐
4
But 975 Hz, R = SiMe3 924 Hz, R = Ph 982 Hz)22 suggesting a
similar trans influence for the cyclometalling sp2 and alkynyl sp
carbons. The Cβ alkyne carbon of the alkynyl fragment trans
to the iminic N atom appears also slightly shifted downfield
(∆δ Cβ 3.8 1 and 2; 2.9 3) and exhibits a notably higher 2J(195Pt–
13C) coupling constant (415 1; 374 2; 433 Hz 3 vs. 230 1; 205 2
and 235 Hz 3) as a result of the very low trans influence of
the iminic N donor atom. For the remaining complexes the
absence of platinum satellites precludes the assignment of these
carbons. On the basis of the data on complexes 1–3 and the
resonances in the corresponding homoleptic species a tentative
assignment is included in the Experimental section.
sional H–1H and H–13C COSY experiments performed on
complex 3 are collected in the Experimental section. The H
1
1
1
NMR spectra (CD3COCD3) exhibit two characteristic low field
doublets of doublets with platinum satellites in the ranges 9.39–
10.17 (ppm) and 8.37–8.66 (ppm) due to the H2 and H9 protons,
respectively. Both signals are considerably shifted to high fre-
quencies in comparison with the free ligand (δ H2 9.29; H9 7.79)
indicating that both rings act as good π acceptors. The 195Pt
coupling constants (25–27.3 Hz for H2 and 35–43 Hz for H9) are
characteristic of values observed for related Pt() complex-
es.10b,m,21 In the high-field region, two different But (δ 1.34, 1.32)
or SiMe3 (δ 0.15, 0.149) resonances in complexes 1 and 2 con-
firm the presence of non-equivalent alkynyl entities. The low
temperature 13C{1H} NMR spectra of all complexes show the
expected resonances for the bzq ligand, in addition to those of
᎐
X-Ray crystal structures of (NBu )[Pt(bzq)(C᎐CR) ], R ؍ Ph 3,
R ؍ C5H4N-2 6
᎐
4
2
The X-ray crystal structures of 3 and 6 were obtained, and their
structural features are almost identical. For complex 6 two dis-
tinct but crystallographically similar anions are found in the
unit cell. Selected bond distances and angles are given in Tables
1 and 2. Drawings of the anion of 3 and one of the anions of 6
(anion A) are given in Fig. 1.
In both molecules the platinum center exhibits the expected
square planar coordination and the benzoquinoline ligand is
essentially flat (the largest deviations from the main planes
defined by the metallocycle atoms are 0.102 Å 3 and 0.144 Å for
ϩ
10
᎐
the NBu4 cation and the two C᎐CR groups (trans to C and
᎐
trans to N). The metalate C10 carbon is found at high frequency
(162.0–164.18 ppm) and the expected large J(195Pt–13C) coup-
1
ling (735–777 Hz) is observed (except for complexes 4 and 7).
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
823

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Table 3 Absorption (∼2 × 10Ϫ5 M solutions) and electrochemical data for complexes 1–7
Compound
Absorption/nm (103 ε/MϪ1 cmϪ1
)
E ox/V
1
2
3
268(34), 308(14.8), 347(11.3), 409(7.7) (CH2Cl2)
272(24.3), 303(10.2), 345(10.4), 392(6.7), 429(2.6) (CH2Cl2)
275(231), 351(18.1), 397(10.3) (CH2Cl2)
0.680
0.852
0.836
352(14.2), 405(9.1) (acetone)
347(27.0), 392(15.6) (CH3CN)
4
5
270(29.4), 285(29.4), 304(23.6)sh, 351(11.1), 408(7.0) (CH2Cl2)
265(406), 306(49.6), 346(30.0), 392(13.0) (CH2Cl2)
345(18.3), 398(8.3) (acetone)
0.820
0.944
329(23.0), 344(23.4), 393(11.9) (CH3CN)
263(33.9), 308(27.2), 348(16.5), 393(8.9) (CH2Cl2)
267(38.5), 335(66.5), 350(67.6), 400(23.2) (CH2Cl2)
6
7
1.006
0.854
3 and 93.74(19)Њ for 6] and the twist angle between the
PtNC(bzq) and the PtCαCα planes (2.5Њ for both complexes) are
comparable to those observed in the related neutral cis complex
12c
᎐
[Pt(phen)(C᎐CTol) ] (92.52Њ; 9.6Њ). The ethynyl groups in 3
᎐
2
and 6 show the expected linear arrangement. Despite the pres-
ence of different trans donor atoms (N and C) the Pt–C acetyl-
ide bond lengths observed [1.985(11) and 2.007(9) Å 3; 1.976(6)
and 1.992(5) Å 6] are identical within experimental error.
These values are slightly longer than those reported for neutral
platinum() diimine bis(acetylide) complexes12 (cf. 1.948(3) Å
in [Pt(phen)(C᎐CTol) ]12c) and in the N–C–N orthometallated
᎐
᎐
2
3
᎐
derivative
[Pt{η -N,C,N-C H (CH᎐NR) -2,6}(C᎐CSiMe )]
᎐
᎐
3
3
2
3
(R = 2,6-iPr2C6H3) (1.945(2) Å)11d but perceptibly shorter than
᎐
the corresponding distances found in [Pt(C᎐CR)(Me NCH -
᎐
2
2
(σ-Fc))(dmso)] (R = SiMe3 2.076(5); Fc 2.059(6) Å).11e Pt–C
bonds to the bzq ring [2.055(7) Å for 3 and 2.050(4) Å for 6] are
slightly longer than the corresponding distances in the homo-
leptic derivative cis-[Pt(bzq)2] [1.999(12), 1.976(9) Å],21 a vari-
ation that may reflect the high trans influence of the alkynyl
ligands. The Pt–N bond distances [2.065(8) 3; 2.074(4) 6] are
shorter than those found in cis-[Pt(bzq)2] [2.153(8) and 2.149(9)
Å],21 probably caused by the higher trans influence of the C(sp2)
aryl carbon relatively to the C(sp) acetylide, but compare well
with those observed in related cycloplatinate complexes which
incorporate a N donor in a five-membered metalacycle.23
Optical properties and TD-DFT calculations
The UV/Vis absorption data are summarised in Table 3. All
complexes show intense absorption bands at 263–351 nm
(ε > 104 MϪ1 cmϪ1) which are probably due to ligand-centred
transitions (1IL π
π*) of the bzq cyclometalated and/or
alkynide groups. Complexes 1–6 also exhibit a moderately
intense low-energy feature (392–409 nm, ε 6.7–13 103 MϪ1 cmϪ1)
with a shoulder at 429 nm in the case of complex 2. Complex 7,
containing the extended diynyl ligand, exhibits an absorption
spectrum that is significantly different, in particular the low
energy band which is located at ca. 400 nm possesses a molar
absorption coefficient that is substantially higher (23200 MϪ1
cmϪ1) than the rest of the complexes. In order to check the
influence of the solvent, the absorption spectra for some com-
plexes (3, 5 and 7) were also collected in acetone and
acetonitrile (see Table 3). The small solvatochromic shift of the
lowest energy absorption is indicative of their charge-transfer
nature.
Ϫ
᎐
Fig. 1 Molecular structure of a) the anion [Pt(bzq)(C᎐CPh)2] in 3,
᎐
Ϫ
᎐
b) the anion [Pt(bzq)(C᎐C–C5H4N-2)2] (A) in 6. Ellipsoids are drawn
at the 50% probability level. Hydrogen atoms are omitted for clarity.
In previous studies with homoleptic, heteroleptic and mixed
platinum() complexes based on cyclometalated C∧N aromatic
ligands,10b,l,m,11a,17,21,23 the solvatochromic low energy absorption
bands in the range 350–450 nm have been mainly attributed to
metal-to-ligand charge-transfer transitions. In the present work
᎐
6), while the phenyl or pyridyl rings of the acetylide are tilted
(27.6 and 118.2 3; 6.9 and 6.2Њ 6) from the platinum coordin-
ation plane. Bond lengths and angles within the anions are the
usual for this type of complex and there are no significant inter-
actions arising from packing arrangements. The small chelate
bite N–Pt–C angles of the bzq ligand [79.7(3) 3 and 80.60(18)Њ
6] are characteristic of five-membered cyclometalated plat-
inum() compounds.10a–c,m,11d,e,21,23 The Cα–Pt–Cα angle [92.4(3)Њ
examination of the spectra for complexes 1–7 and comparison
᎐
with related homoleptic (NBu ) [Pt(C᎐CR) ] complexes indi-
᎐
4
2
4
cates the following points.Firstly, it is evident that the aggregate
transition comprising the low energy band (∼400 nm) shifts to
lower energy as the electron donating properties of the acetylide
t
᎐
᎐
᎐
substituents increase (Bu ∼ Tol > C᎐C–C H –C᎐CPh ∼ C᎐CPh
᎐
᎐
᎐
6
4
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
824

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Table 4 Population analysis (%) for the anion [Pt(bzq)(C᎐CPh)2]Ϫ 3
Table 5 Population analysis (%) for the anion [Pt(bzq)(C᎐CC6H4–
᎐
᎐
᎐
᎐
᎐
C᎐CPh)2]Ϫ 7
᎐
᎐
᎐
Pt
(C᎐CPh)2 [(C᎐C)2]
bzq
᎐
᎐
᎐
᎐
Pt
(C᎐CC6H4–C᎐CPh)2
bzq
᎐
᎐
HOMO Ϫ 5
HOMO Ϫ 4
HOMO Ϫ 3
HOMO Ϫ 2
HOMO Ϫ 1
HOMO
8.5
37.9 [6.3]
58.8 [1.4]
40.7 [8.1]
56.3 [20.2]
60.6 [20.9]
58.6 [18.4]
15.2 [4.2]
22.9 [4.9]
65.4 [9.9]
71.6 [9.1]
53.7
29.1
30.2
28.3
24.8
25.4
77.4
71.2
28.2
23.5
12.1
29.1
15.4
14.6
16.0
7.4
5.8
6.4
4.9
HOMO Ϫ 3
27.7
11.5
11.9
13.6
2.7
1.9
4.3
42.3
62.6
67.3
62.6
80.0
76.6
53.7
30.0
25.9
20.7
23.8
17.4
21.5
41.9
0
HOMO Ϫ 2
HOMO Ϫ 1
HOMO
LUMO
LUMO
LUMO ϩ 1
LUMO ϩ 2
LUMO ϩ 3
LUMO ϩ 1
LUMO ϩ 2
LUMO ϩ 3
0
100
composition to complex 3 with π alkynyl contributions of over
60% (Table 5), the first two unoccupied orbitals, LUMO and
᎐
᎐
> C᎐C–C H –CF ∼ C᎐C–Py-2 ∼ SiMe ) suggesting that the
᎐
᎐
6
4
3
3
᎐
᎐
᎐
HOMO is predominantly metal perturbed π C᎐CR centred
LUMO ϩ 1, are mainly π*–C᎐C–C H –C᎐CPh in character
᎐
6 4
᎐
᎐
ligand or metal based. Secondly, for complexes 1–6 these bands
are significantly red-shifted from the analogous low energy
absorptions observed in the corresponding homoleptic com-
(ca. 80%), the contribution of the Pt to these latter orbitals
being negligible (∼2%). The contribution of the bzq ligand is
᎐
only notable in the LUMO ϩ 2, which is a mixed C᎐CR (54%)/
᎐
᎐
plexes (NBu ) [Pt(C᎐CR) ] which are tentatively assigned as
bzq (42%) orbital, but it is located at 0.79 eV from the LUMO;
the LUMO ϩ 3 is again of a virtually pure alkynyl character.
As a further means of examining the properties of the
HOMO and LUMO orbitals, we obtained cyclic voltam-
mograms of all complexes in CH2Cl2 (0.1 mol dmϪ3 NBu4PF6)
and the results are also summarized in Table 3. All the com-
plexes exhibit, within the solvent window, only one irreversible
oxidation wave in the range of 0.68 to 1.006 eV vs. Fcϩ/Fc. This
result is in agreement with previous reports on Pt() cyclometal-
ated systems and other Pt() complexes containing diimine or
related chelating aromatic ligands that show irreversible oxid-
ations usually assigned as metal-centred oxidation from Pt() to
Pt(). However, the typical reversible reduction processes usu-
ally seen in these systems were not observed in our complexes
probably due to the anionic nature of these species. For com-
plex 1 the voltammogram was also recorded in THF and DMF
with identical results. The observation that the anodic potential
in general decreases as the π-donating abilities of the alkynyl
᎐
4
2
4
1
᎐
᎐
MLCT (Pt d/π C᎐CR
for (NBu ) [Pt(C᎐CPh) ]). This fact suggests that the LUMO of
π* C᎐CR) (i.e. 397 nm 3 vs. 362 nm
᎐
᎐
᎐
᎐
4
2
4
the optical transition is presumably localized on the bzq ligand.
For these complexes, the low energy transitions observed are
therefore mainly attributed to spin-allowed metal perturbed
ligand (acetylide)-to-ligand (benzoquinolinate) charge-transfer
᎐
(Pt d/π C᎐CR
π* bzq). For complex 2 the long wavelength
᎐
shoulder located at 429 nm is tentatively assigned as a transition
to the corresponding triplet state. The proposed assignment is
additionally supported by DFT calculations on complex 3,
which give an overall picture of the valence orbitals. The
B3LYP density functional theory (DFT) calculations essentially
reproduce the experimental structure of complex 3. The relative
compositions of the different energy levels in terms of compos-
ing fragments are reported in Table 4. As can be seen the
HOMO is a π orbital which is predominantly formed by the
᎐
C᎐CPh fragments with additional contributions from Pt(5d)
᎐
(16%) and the orthometallated phenyl portion (25%) of the
substituents increase is further evidence of the involvement of
᎐
bzq. The HOMO Ϫ 1 and HOMO Ϫ 2 also consist of a roughly
the Pt(d)–πC᎐CR interaction in the HOMO. The oxidation of
᎐
᎐
60% contribution of the C᎐CPh fragments and similar contri-
the bis(tert-butylacetylide) complex 1 occurs at a lower poten-
tial than for the others. This fact may be ascribed to the
presence of the most electron donating alkynyl ligand which
increases the energy of the dπ (Pt) orbital and is also in agree-
ment with the lowest absorption and emission (see below)
᎐
butions of Pt and bzq orbitals. The lowest lying unoccupied
molecular orbital LUMO is mainly localised over the bzq
ligand with a notable contribution of the orbitals of the pyridyl
and central fused aromatic ring. The LUMO ϩ 1 is also centred
in the C∧N ligand while the following unoccupied molecular
energies observed for this complex. In contrast the presence of
᎐
᎐
orbitals are π* C᎐CR in character, being located 1.47 and 1.73
electron withdrawing alkynyl groups such as C᎐C–C H -CF -4
᎐
᎐
6
4
3
᎐
eV respectively above the LUMO.
or C᎐C–C H N-2 makes the complexes harder to oxidise.
᎐
6 4
The overall picture is similar to those reported recently
The emission spectra of all complexes have been recorded in
the solid state (RT, KBr pellets), at room temperature in CH2Cl2
solution and at 77 K in CH2Cl2 glass. The complexes are
intensely emissive in the solid state (except complex 7) and in
low temperature glasses and moderately luminescent in fluid
solution. Similar spectra were obtained in concentrated solvent
glasses excluding excimer formation. Representative compar-
isons between solid state, fluid solution and glass emission
spectra for complexes 1 and 7 are provided in Fig. 2 and 3 while
Table 6 summarises the emission maxima, emission lifetimes
(solid state) and quantum yields.
᎐
᎐
for model complexes [Pt(C᎐CH) (COD)] and [Pt(C᎐CH) -
᎐
᎐
2
2
(iPr-DAB)] (iPr-DAB = N,NЈ-diisopropyl-1,4-diazabutadiene)
based on DFT calculations.24 In contrast to previous assign-
ments12,16a (as MLCT transitions) the low absorption bands
᎐
᎐
found in complexes [Pt(C᎐CH) (COD)] and [Pt(C᎐CH) -
᎐
᎐
2
2
(iPr-DAB)] have been also attributed to LЈLCT and mixed
᎐
MLCT/LЈLCT or LЈLCT [LЈLCT = ligand (C᎐CR)-to-ligand
᎐
(π* diimine) charge transfer] transitions respectively.24 In
platinum chemistry LЈLCT transitions have been also found in
α-diimine bis-thiolate compounds.16,25
For complex 7 the low-energy band has a high extinction
coefficient and does not show a notable solvatochromic effect
suggesting the notable contribution of an additional different
transition. In this case the lowest optical transition is attributed
With respect to the PL spectra there are several noteworthy
features. First, the emissive properties of complexes 1–6 are
similar suggesting that the photoluminescence of these deriv-
atives emanates from the same type of excited state. A clear
deviation is found in complex 7, which will be described separ-
ately. For complexes 1–6 the solid state emission spectral band
shapes (broad with a long tail to lower energies) were similar to
the corresponding solution (RT) values, although emission
maxima were consistently at shorter wavelengths (except 3), this
hypsochromic shift being, probably, a reflection of restricted
excited-state distortion in the solid matrix environment. A
second point to be noted is that, upon cooling at 77 K, the
to a transition based on the extended alkynyl ligand having
᎐
mainly metal perturbed π
π* (C᎐CR) character. Additional
᎐
evidence supporting this assignment is based on DFT calcu-
lations (Table 5). In this case the electronic structure is
somewhat different from that of 1–6 and this is due to the
᎐
᎐
fact that the extended C᎐C–C H –C᎐C–Ph alkynyl ligands
᎐
᎐
6
4
have relatively low-lying unoccupied π* orbitals. Thus, while
the highest-lying four MOs of complex 7 have a similar
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
825

View Article Online
Table 6 Emission and excitation spectral data for complexes 1–7 in KBr and in 10Ϫ3 M solutions
Compound
λexc/nm
λem/nm
ꢀ
τ/µs
1
KBr (298)
398, 468
468
533
561
0.82
0.73
0.52
CH2Cl2 (298)
CH2Cl2 (77)
KBr (298)
CH2Cl2 (298)
CH2Cl2 (77)
KBr (298)
CH2Cl2 (298)
CH2Cl2 (77)
Acetone (298)
Acetone (77)
CH3CN (298)
CH3CN (77)
KBr (298)
CH2Cl2 (298)
CH2Cl2 (77)
KBr (298)
CH2Cl2 (298)
CH2Cl2 (77)
Acetone (298)
Acetone (77)
CH3CN (298)
CH3CN (77)
KBr (298)
CH2Cl2 (298)
CH2Cl2 (77)
KBr (298)
0.069
0.025
0.056
357, 394, 421, 452, 487(sh)
396, 448, 476
457
347, 394, 433, 472
401, 427, 462, 499(sh)
462
352, 400, 447, 473
475
304, 348, 398, 440, 474
469
318, 358, 397, 447, 484
392, 460
470
345, 398, 444, 477
333, 393, 458
461
354, 398, 433, 473
473
330, 393, 435, 473
454
357, 395, 429, 473
333, 394, 459
456
354, 399, 432, 474
356, 393, 473
473
512, 547, 586(sh)
515
521
493, 532, 570
527, 598
526
505, 538, 581
537
493, 526, 569
534
509, 541, 594(sh)
530
534
505, 540, 581(sh)
513, 530
511
492, 526, 568
521
495, 528, 567(sh)
516
488, 524, 564
508, 583(sh)
517
495, 530, 569
544, 570, 604, 622
537, 567
2
3
4
5
0.79
0.78
0.181
0.023
6
7
0.13
—
0.012
0.067
CH2Cl2 (298)
CH2Cl2 (77)
356, 392, 424, 445, 471
535, 562, 589, 598, 636
comparable to those reported for many cyclometalated and
diimine platinum() complexes and has been linked to solvent–
solute interactions in fluid solution which seem to stabilise
the excited state emissive. Intrinsic lifetimes (solid state, KBr
pellets) in the submicrosecond range and the separation
between the lowest energy excitation and the highest energy
emission band (Table 6) are indicative of metal complex phos-
phorescence. The solution emission quantum yields determined
according to the method described by Demas and co-workers26
(Table 6) are in the range 0.012 to 0.181 and compare well with
those observed for analogous cyclometalated neutral complexes
such as [Pt(C∧N)(O∧O)]10b (0.02–0.25).
For complexes 3 and 5 the emission spectra were also
recorded in acetone and acetonitrile. The observation of small
solvatochromic shifts (see Table 6) is consistent with charge-
transfer excited states. The emission maxima in CH2Cl2 at 298
K are modified from 561 nm for 1 to 511 nm for 5 (1711 cmϪ1)
illustrating the slight tunability of the emission depending on
the nature of the acetylide substituent. Clearly, the emission
maximum shifts to lower energy as the π orbital energy and
donor capability of the acetylide ligand increase, in keeping
Fig. 2 Normalised emission spectra of 1 in KBr (—), in fluid CH2Cl2
solution at room temperature ( ؒ ؒ ؒ ) and at 77 K (---).
᎐
᎐
with a mainly π C᎐CR or Pt(d)/π C᎐CR based HOMO. There-
᎐
᎐
fore, for these complexes the origin of this emission band is
3
᎐
assigned as a triplet metal-perturbed LЈLCT [Pt(d)/π C᎐CR
᎐
π* bzq] excited state. The main TD-DFT calculated excitation
energies for the anion of complex 3, which are tabulated in
Table 7 and shown in Fig. 4, are in good agreement with the
experimental excitations. The two intense calculated excitations
at ca. 397 and 449 nm are mainly attributed to HOMO
LUMO ϩ 1 and HOMO Ϫ 2
LUMO supporting a metal-
perturbed LЈLCT assignment. The lowest calculated singlet
(HOMO
and HOMO Ϫ 3
518 nm) excitations are in reasonable agreement with the
LUMO 547 nm, HOMO Ϫ 1
LUMO 516 nm
Fig. 3 Normalised emission spectra of 7 in KBr (—), in fluid CH2Cl2
solution at room temperature (---) and at 77 K ( ؒ ؒ ؒ ).
LUMO 463 nm) and triplet (576, 559 and
experimental emission (λmax 527 nm).
Complex 7 (with cis-configured C᎐C–C H –C᎐CPh moieties)
᎐
6 4
᎐
᎐
᎐
emission profiles of these complexes (1–6) became intensified
and structured with maxima shifted to higher energies. The
vibronic interval is ca. 1300 cmϪ1 which is indicative of cyclo-
metalated bzq ligand involvement in the emissive excited state.
The small rigidochromic blue shift (19–49 nm) observed is
displays different solid-state, solution and glassy emissions in
comparison to complexes 1–6 (Fig. 3). The observed structured
emission in CH2Cl2 solution and the absence of rigidochromic
behaviour suggest that the nature of the excited state is
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
826

View Article Online
Table 7 TD-DFT RPA (random phase approximation) singlet excitation calculations for [Pt(bzq)(C᎐CPh)2]Ϫ 3
᎐
᎐
Transition
Contributions
o.s.
λexc(calc.)/nm
HOMO Ϫ 2
HOMO Ϫ 1
HOMO Ϫ 3
HOMO
HOMO Ϫ 1
HOMO Ϫ 4
HOMO Ϫ 2
HOMO Ϫ 5
HOMO Ϫ 5
HOMO Ϫ 2
LUMO
LUMO
LUMO
0.58
0.22
0.20
0.66
0.12
0.11
0.66
0.14
0.65
0.13
0.148
448.8
LUMO ϩ 1
0.062
396.8
LUMO ϩ 1
LUMO
LUMO ϩ 1
LUMO
LUMO
0.088
0.045
365.7
347
LUMO ϩ 1
analyses were carried out with a Carlo Erba EA1110 CHNS-O
microanalyzer. Mass spectra were obtained on a HP-5989B
mass spectrometer (ES(Ϫ) technique) and conductivities were
measured in acetone solutions (ca. 5 × 10Ϫ4 molϪ1) with a
Crison GLP 31 conductimeter. Emission and excitation spectra
were obtained on a Perkin-Elmer Luminescence Spectrometer
LS 50B and emission lifetime measurements were performed
with a dye laser (Lamda-Physik, LPD 3002 CES, ∆λ = 0.2 cmϪ1;
λ = 337, > 5 mJ pulseϪ1 in the range 332–350 nm, dye p-ter-
phenyl in dioxane) pumped by an excimer XeCl laser (Lamda-
Physik, LPX 105i, λ = 308 nm, 200 mJ pulseϪ1, FWHM ∼ 20 ns).
The solution emission quantum yields were measured by the
Demas and Crosby26 method using [Ru(bipy)3]Cl2 in degassed
acetonitrile as the standard. The platinum precursor [Pt(bzq)-
(µ-Cl)]2 (bzqH = benzo[h]quinoline) was prepared according
to the reported procedure.27 Alkynes, except for H–C᎐C–C H –
᎐
Ϫ
᎐
᎐
6
4
28
Fig. 4 Calculated excitation spectrum (bars) of [Pt(bzq)(C᎐CPh)2]
᎐
᎐
C᎐CPh which was prepared following a standard procedure,
and experimental solid-state (RT, KBr pellets) excitation and emission
spectra of complex 3.
᎐
were purchased from commercial suppliers and used as
received. Cyclic voltammetric studies were performed using an
EG&G 283 potentiostat/galvanostat. Anhydrous CH2Cl2 was
used as the solvent under a nitrogen atmosphere, and 0.1 M
tetra(n-butyl)ammonium hexafluorophosphate was used as the
supporting electrolyte.
different. Significantly, the glassy (77 K) peak maxima are simi-
lar to the emission peaks observed for the homoleptic derivative
᎐
᎐
(NBu ) [Pt(C᎐C–C H –C᎐CPh) ] (541, 570, 588, 607 nm). In
᎐
᎐
4
2
6
4
4
complex 7 a mixed IL/MLCT excited state that originates from
the alkynyl entities or the existence of two closely emissive
᎐
᎐
᎐
states of type π–π* C᎐CR/Pt(d)–π C᎐CR
π* C᎐CR is ten-
᎐
᎐
᎐
Computational details
tatively suggested as the origin of the emission. The consider-
able red shift of its glassy emission (535 nm) relative to 1–6
could be tentatively attributed to the low-lying delocalized
nature of the butadiynyl moieties, which affords LUMO
stabilisation.
In this work, the experimental crystal structure of the anion
Ϫ
᎐
[Pt(bzq)(C᎐CPh) ] 3, and a model of the anion [Pt(bzq)-
᎐
2
Ϫ
᎐
᎐
(C᎐CC H C᎐CPh) ] 7, based on the structure of 3, were used.
᎐
᎐
6
4
2
The density functional calculations were performed on isolated
molecules using the Gaussian 98 program package29 at the
B3LYP level.30 The basis set for the platinum atom was
LANL2DZ,31 with the corresponding ECP (effective core
potential), and 6-31G(d,p) for the C, N and H atoms. The exci-
tation energies for 3 were obtained using the Time Dependent
Theory (TD-DFT).
Conclusion
In summary the synthesis, electronic absorption, luminescence
and electrochemical properties of novel bis(alkynyl)platinate
᎐
compounds (NBu )[Pt(bzq)(C᎐CR)] 1–7 containing the planar
᎐
4
orthometallated 7,8-benzoquinoline ligand (bzq) have been
described. For complex 1–6 the low energy transitions observed
are mainly attributed on the basis of TD-DFT calculations to
metal perturbed ligand (acetylide)-to-ligand(benzoquinolinate)
charge transfer. For complex 7 containing the extended di-
Crystal structure determinations for 3 and 6
Both experiments were performed at 293 K in a κ-CCD area
diffractometer using graphite-monochromated Mo-Kα radi-
ation. All calculations were carried out using the SHELXL-9732
program and the data reduction with HKL Denzo ScalePack.33
The structures were solved by direct methods and refined on F 2.
All hydrogen atoms were constrained to idealised geometries
and were assigned isotropic displacement parameters equal to
1.2 times the Uiso value of their attached carbon for the aro-
matic and CH2 hydrogens and 1.5 times for the methyl groups.
Absorption corrections were carried out using the SORTAV34
program.
᎐
᎐
alkynyl ligand C᎐C–C H –C᎐C–Ph the lowest optical transi-
᎐
᎐
6
4
tion (absorption and emission) is attributed to a transition
᎐
᎐
having mainly metal perturbed π–π*(C᎐C–C H –C᎐C–Ph)
᎐
᎐
6
4
character.
Experimental
General procedures
All reactions were carried out under nitrogen atmosphere and
solvents were dried by standard procedures and distilled under
dry N2 before use. Proton (300 MHz) and 13C{1H}NMR
spectra were recorded on a Bruker ARX-300 spectrometer with
chemical shifts externally referenced to SiMe4. Infrared spectra
were recorded with a Perkin-Elmer FT-IR1000 spectrometer
as Nujol mulls between polyethylene sheets and C, H and N
Crystallographic data for 3: C45H54N2Pt, M = 817.99,
monoclinic, space group P21/n, a = 20.7488(4), b = 8.6637(2),
c = 24.5454(6) Å, β = 113.3822(8)Њ, V = 4049.97(16) Å3, Z = 4,
ρcalc = 1.342 g cmϪ3, F(000) = 1664, µ(Mo-Kα) = 3.495 mmϪ1,
λ = 0.71073 Å. The 23343 reflections measured yielded 8130
unique data (Θmax = 26.37Њ, Rint = 0.0515), 437 parameters,
R1 = 0.0599 [I > 2σ(I )], wR2 = 0.1472.
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
827

View Article Online
Crystallographic data for 6: C43H52N4Pt, M = 818.46,
monoclinic, space group P21/n, a = 19.3798(2), b = 16.8231(2),
c = 25.2980(4) Å, β = 108.9762(5)Њ, V = 7799.62(17) Å3, Z = 8,
ρcalc = 1.394 g cmϪ3, F(000) = 3316, µ(Mo-Kα) = 3.631 mmϪ1,
λ = 0.71073 Å. The 47259 reflections measured yielded 15798
unique data (Θmax = 26.37Њ, Rint = 0.0531), 872 parameters,
R1 = 0.0417 [I > 2σ(I )], wR2 = 0.0796.
CCDC reference numbers 197073 and 197074.
See http://www.rsc.org/suppdata/dt/b2/b210907g/ for crystal-
lographic data in CIF or other electronic format.
(CH2); 13.75 (CH3, NBu4); 1.85 (s, SiMe3); 1.54 (s, SiMe3);
m/z = 567 (MϪ, 100%). ΛM (acetone): 81 molϪ1 cm2 ΩϪ1.
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐CPh) ] 3
᎐
4
2
᎐
To a fresh (Ϫ25 ЊC) solution containing 8 equiv. of LiC᎐CPh
᎐
(2.446 mmol) in Et2O (30 mL) was added [Pt(bzq)(µ-Cl)]2
(0.25 g, 0.306 mmol) and the mixture was allowed to reach
room temperature. The mixture was then stirred for 2.5 h and
the remaining steps were identical to the procedure described
for 2 (0.25 g, 50%). (Found: C, 66.00; H, 7.09; N, 3.23.
C45H54N2Pt requires C, 66.07; H, 6.65; N, 3.42%); νmax/cmϪ1
t
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐C Bu) ] 1
᎐
᎐
4
2
(C᎐C) 2103s and 2080s (Nujol). δ (CD3COCD3, J/Hz): 10.17
᎐
H
(d, J = 4.3, 3J(Pt–H) = 25, H2); 8.63 (dd, J = 5.9, 1.8, 3J(Pt–H) =
43, H9); 8.49 (dd, J = 7.22, 1.2, H4); 7.79 (d, J = 8.8, H5); 7.64
(m); 7.53 (m); 7.39 (m) (H3, H6–8, 4H Ph); 7.20 (4H, Ph); 7.04
(m, 2H, Ph); 3.43 (m, NCH2, NBu4); 1.65 (m, –CH2–, NBu4);
1.24 (q, –CH2–, NBu4); 0.81 (t, –CH3, NBu4). δC{1H} (CDCl3,
J/Hz, 240 K): 162.73 (1JPt–C = 777 C10); 157.49 (2JPt–C ∼ 50, C12);
150.04 (C2); 143.46 (C11); 135.96 (C4); 134.49 (2JPt–C ∼ 90, C9);
132.87 (C13,14); 131.41(Co, Ph); 131.01 (Co, Ph); 130.09 (C7,8);
129.4 (C7,8); 129.22 (Cp, Ph); 129.12 (Cp, Ph); 127.6 (Cm, Ph);
[Pt(bzq)(µ-Cl)]2 (0.25 g, 0.306 mmol) was added to a fresh
t
᎐
solution of LiC᎐C Bu (2.446 mmol) (1 : 8 molar ratio) in
᎐
diethyl ether/hexane (25 mL) at low temperature (Ϫ40 ЊC) and
the mixture was allowed to warm to room temperature. After
stirring for 30 min the solvent was evaporated and the result-
ing yellow solid was extracted with cold deoxygenated water
(50 mL). The resulting yellow aqueous solution was rapidly
filtered under N2 through celite and, the filtrate treated with
vigorous stirring with a solution of (NBu4)Br (0.197 g, 0.611
mmol) in 10 mL of H2O. The resulting yellow solid 1 was
filtered, washed with deoxygenated water and air-dried
(0.34g, 83%); (Found: C, 62.34; H, 7.61; N, 3.92. C41H62N2Pt
127.54 (Cm, Ph); 127.3 (Ci, Ph); 126.0 (C13,14); 124 (Ci, Ph); 123.8
10
(C ᎐CPh trans to C ; 195Pt are not clearly resolved); 122.49
᎐
᎐
α
(C5,6); 121.14 (C3); 120.10 (C5,6); 106.4 (2JPt–Cβ = 235, ᎐C Ph
᎐
᎐
β
trans to C10); 103.49 (2JPt–Cβ = 433, ᎐C Ph trans to N); 98.05
᎐
requires C, 62.26; H, 8.03; N, 3.60%); νmax/cmϪ1 (C᎐C) 2108s
᎐
β
᎐
᎐
(1JPt–Cα = 1488, C ᎐CPh trans to N); 57.7 (N–CH ); 23.34 (CH );
᎐
᎐
α
2
2
and 2099vs (Nujol); δH(CD3COCD3, J/Hz): 9.39 (dd, J = 5.4,
19.12 (CH2); 13.66 (CH3, NBu4), m/z = 576 (MϪ, 100%). ΛM
1.2, 3J(Pt–H) = 25.5, H2); 8.66 (dd, J = 6, 2.4, 3J(Pt–H) = 40.2,
H9); 8.40 (dd, J = 7.8, 1.2, H4); 7.72 (d, J = 8.7, H5); 7.57 (d,
J = 8.7, H6); 7.5 (dd, J = 7.8, 5.4, H3); 7.45 (m, H7,8);
(acetone): 90 molϪ1 cm2 ΩϪ1
t
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐CTol) ] 4
᎐
3.46 (m, NCH2, NBu4); 1.62 (m, –CH2–, NBu4); 1,34 (s, Bu);
4
2
t
1,32(s, Bu); 1.22 (q, –CH2–, NBu4); 0.83 (t, –CH3, NBu4).
᎐
To a fresh (Ϫ15 ЊC) solution containing 8 equiv. of LiC᎐CTol
᎐
δC{1H} (CDCl3, J/Hz, 233 K): 164.18 (1JPt–C = 770, C10); 157.75
(2JPt–C = 48, C12); 149.71 (2JPt–C ∼ 40, C2); 143.3 (C11); 134.94
(C4); 134.5 (C9); 133.26 (C13,14); 129.14, 128.99 (C7,8); 125.65
(2.446 mmol) in Et2O (30 mL) [Pt(bzq)(µ-Cl)]2 (0.25 g,
0.306 mmol) was added and the mixture was stirred at this
temperature for 2 h. The mixture was then allowed to reach
room temperature (ca. 1 h.). The solvent was evaporated to
dryness and the yellow solid residue extracted with a mixture of
i-PrOH/deoxygenated water (10/50 mL). The resulting yellow
aqueous solution was rapidly filtered under N2 through celite
and, the filtrate treated with vigorous stirring with a solution of
(NBu4)Br (0.197 g, 0.611 mmol) in 10 mL of H2O; (0.13g, 32%);
(Found: C, 66.73; H, 6.81; N, 3.59%. C47H58N2Pt requires C,
(C13,14); 122.08 (C5,6); 120.7 (C3); 118.8 (C5,6); 113.36 (2JPt–Cβ
=
t
10
1
t
᎐
᎐
230, ᎐C Bu trans to C ); 110.95 ( J
= 902, C ᎐CBu
᎐
᎐
β
Pt–Cα
α
trans to C10); 109.5 (2JPt–Cβ = 415, ᎐C Bu trans to N); 77.7
t
᎐
᎐
β
t
(1JPt–Cα = 1490, C ᎐CBu trans to N); 57.5 (N–CH ); 32.95
᎐
᎐
α
2
(C(CH3)); 32.26 (C(CH3)); 29.37 (C(CH3)); 29.00 (C(CH3));
23.34 (CH2); 18.90 (CH2); 13.74 (CH3, NBu4); m/z 535 (MϪ,
Ϫ
t
Ϫ
᎐
100%), 1071 (M , 20), 989 (M Ϫ C᎐C Bu , 20). ΛM (acetone):
᎐
2
2
101 molϪ1 cm2 ΩϪ1.
66.72; H, 6.90; N, 3.30%); νmax/cmϪ1 (C᎐C) 2105s and 2082s
᎐
᎐
3
(Nujol). δH (CD3COCD3, J/Hz): 10.17 (d, J = 4.3, J(Pt–H) =
3
25,8, H2); 8.63 (dd, J = 6.0, 1.7, J(Pt–H) = 41, H9); 8.48 (d,
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐CSiMe ) ] 2
᎐
4
3 2
J = 7.9, H4); 7.78 (d, J = 8.7, H5); 7.62 (m); 7.52 (m) (H3, H6–8);
7.30 (d, J = 7.7 4H, CH, Tol); 7.02 (d, J = 7.7, 4H, CH, Tol);
3.47 (m, NCH2, NBu4); 2.88(s, 6H, CH3, Tol); 1.66 (m, –CH2–,
NBu4); 1.29 (m, –CH2–, NBu4); 0.80 (t, –CH3, NBu4). 13C{1H}
(CDCl3, 260 K): 162.94 (C10); 157.67 (C12); 149.97 (C2); 143.5
(C11); 135.6 (C4); 134.6 (C9); 133.4 (C13,14); 133.10 (C4, Tol);
132.9 (C4; Tol); 131.00 (CH, Tol); 130.75 (CH, Tol); 129.19
(C7ϩ8 bzq); 128.31 (CH, Tol); 128.20 (CH, Tol); 128.03 (s, this
᎐
To a solution of LiC᎐CSiMe (2.446 mmol) prepared from
᎐
3
n
᎐
HC᎐CSiMe (0.338mL, 2.446 mmol) and LiBu (2.43 mmol) in
᎐
3
Et2O (30 mL) at Ϫ25 ЊC [Pt(bzq)(µ-Cl)]2 (0.25 g, 0.306 mmol)
was added and the mixture was stirred at this temperature for
10 min. The reaction mixture was then allowed to warm to 25
ЊC and, after stirring for 30 min, all volatile materials were
removed in vacuo. The resulting residue was extracted with cold
i-PrOH, filtered and treated with (NBu4)Br (0.197 g, 0.611
mmol) affording 2 as a yellow solid (0.25 g, 51%); (Found: C,
57.53; H, 7.66; N, 3.40. C39H62N2PtSi2 requires C, 57.82; H,
10
᎐
signal could be tentatively assigned to C ᎐CTol trans to C );
᎐
α
127.18 (C1, Tol); 126.53 (C1, Tol); 122.97 (C13,14); 122.22 (C5,6);
3
5,6
10
᎐
120.88 (C , bzq); 119.84 (C ); 106.3 (᎐C Tol trans to C ); 103.3
᎐
β
7.71; N, 3.46%); νmax/cmϪ1 (C᎐C) 2031vs and 2008vs (Nujol).
᎐
(᎐C Tol trans to N); 97.0 (C ᎐CTol trans to N, 195Pt satellites are
᎐
᎐
᎐
᎐
᎐
β
α
δH (CD3COCD3, J/Hz): 10.16 (dd, J = 5.2, 1.2, 3JPt–H = 25.9, H2);
not resolved); 57.93 (N–CH2); 23.53 (CH2); 21.2 (CH3, Tol);
19.13 (CH2); 13.49 (CH3, NBu4); m/z = 603 (MϪ, 100%); ΛM
(acetone): 110 molϪ1 cm2 ΩϪ1.
8.58 (dd, J = 6.4, 1.6, 3JPt–H = 40.2, H9); 8.45 (dd, J = 8, 1, H4);
7.76 (d, J = 8.7, H5); 7.61 (d, J = 8.7, H6); 7.55 (dd, J = 8; 5.2,
H3); 7.48 (m, H7,8); 3.45 (m, NCH2, NBu4); 1.68 (m, –CH2–,
NBu4); 1.27 (q, –CH2–, NBu4); 0.85 (t, –CH3, NBu4); 0.15
(s, SiMe3); 0.149 (s, SiMe3). δC{1H} (CDCl3, J/Hz, 233 K):
163.0 (1JPt–C = 759.9, C10); 157.49 (2JPt–C = 28.2, C12); 152.38
᎐
Synthesis of (NBu4)[Pt(bzq)(C᎐CC6H4CF3-4)2] 5
᎐
[Pt(bzq)(µ-Cl)]2 (0.20 g, 0.245 mmol) was added to a solution
10
2
(1JPt–Cα = 895, C ᎐CSiMe trans to C ); 149.77 ( JPt–C ∼ 45, C2);
containing 10 equiv. of the lithiated ligand (HC᎐CC H CF -4,
᎐
᎐
᎐
᎐
α
3
6
4
3
149.28 (s, C11); 135.9 (C4); 135.8 (2JPt–C = 94, C9); 132.68
0.4 mL, 2.45 mmol, and n-BuLi 1.52 mL, 2.45 mmol) in ether
(30 mL) at Ϫ15 ЊC. The reaction mixture was allowed to warm
slowly to room temperature (ca. 1 h) and then evaporated to
dryness. The residue was extracted with cold i-PrOH (30 mL),
filtered under nitrogen and the filtrate stirred with a solution of
(C13,14); 129.2 (C7,8); 125.9 (C13,14); 122.19 (C5,6); 120.8 (C3);
119.9 (C5,6); 119.24 (1JPt–Cα = 1407, C ᎐CSiMe trans to N);
᎐
᎐
α
3
107.71 (2JPt–Cβ = 205, ᎐C SiMe trans to C ); 103.9 ( J
=
10
2
᎐
᎐
β
3
Pt–Cβ
᎐
374, ᎐C SiMe trans to N); 57.6 (N–CH ); 23.40 (CH ); 18.94
᎐
β
3
2
2
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
828

View Article Online
(NBu4)Br (0.16 g, 0.5 mmol) in deoxygenated H2O to yield
complex 5 as a yellow solid (0.27g, 57%); (Found: C, 58.88; H,
5.23; N, 2.66. C47H52N2Pt requires C, 59.17; H, 5.49; N, 2.93%);
Acknowledgements
This work was supported by the Spanish Ministerio de Ciencia
y Tecnología (Projects PB 98 1595-C01,02 and BQU2002-
03997-C0,C1, PGE, FEDER) and the Government of La Rioja
(APCI-b 2000 15). B. Gil thanks C.S.I.C. for a grant and
S. Fernandez thanks the government of La Rioja for a
Postdoctoral grant. We would also like to express our gratitude
to Dr P. Puyuelo for experimental assistance in laser
instrumentation.
νmax/cmϪ1 (C᎐C) 2105vs and 2082vs (Nujol). δ (CD3COCD3,
᎐
᎐
H
3
J/Hz): 10.1 (dd, J = 5.4, 1.2, J(Pt–H) = 27.3, H2); 8.54 (dd,
3
J = 6.3, 1.5, J(Pt–H) = 41, H9); 8.53 (d, J = 10.4, H4); 7.8 (d,
J = 8.7, H5); 7.65 (m, H6,3); 7.53 (dbr, 10H, H7,8 bzq and CH,
C6H4CF3); 3.45 (m, NCH2, NBu4); 1.74 (m, –CH2–, NBu4);
1.35 (q, –CH2–, NBu4); 0.89 (t, –CH3, NBu4). δF (CDCl3):
Ϫ145.58 (s, CF3); Ϫ145.67 (s, CF3). δC{1H} (CDCl3, J/Hz,
240 K): 162.0 (1JPt–C = 735, C10); 157.37 (C12); 149.94 (C2);
143.4 (C11); 136.37 (C4); 134.4 (C9); 133.7 (C–CF3); 133.01
(C13,14, C–CF3); 131.17 (Co; C6H4–CF3); 131.03 (Co–C6H4–CF3);
129.34 (C7ϩ8); 128.15 (Ci, C6H4–CF3); 127.04 (Ci; C6H4–CF3);
References
1 (a) R. Nast, Coord. Chem. Rev., 1988, 100, 319; (b) E. Sappa,
A. Tiripicchio and P. Braunstein, Coord. Chem. Rev., 1985, 65, 219;
(c) S. Lotz, P. H. Van Rooyen and R. Meyer, Adv. Organomet.
Chem., 1995, 370, 219; (d ) J. Forniés and E. Lalinde, J. Chem. Soc.,
Dalton Trans., 1996, 2587 and references therein; (e) J. Manna,
K. D. John and H. D. Hopkins, Adv. Organomet. Chem., 1995, 38,
79; ( f ) W. Beck, B. Niemer and M. Wiesner, Angew. Chem., Int. Ed.
Engl., 1993, 32, 923; (g) U. Rosenthal, P. M. Pellny, F. G. Kirchbauer
and V. V. Burlakov, Acc. Chem. Res., 2000, 33, 119; (h) U. Belluco,
R. Bertani, R. A. Michelin and M. Mozzon, J. Organomet. Chem.,
2000, 600, 37; (i) H. Lang, D. S. A. George and G. Rheinwald,
Coord. Chem. Rev., 2000, 206–207, 101.
126.17 (C13,14); 125.06 (C ᎐CC H CF trans to C10); 124.56
᎐
᎐
α
6
4
3
(Cm, C6H4–CF3); 127.7 (CF3); 125.0 (CF3); 122.62 (C5,6); 121.26
(C3); 120.59 (C5,6); 105.8 (2JPt–Cβ = 234, ᎐C C H CF trans to
᎐
᎐
β
6
4
3
10
᎐
᎐
᎐
β
C ); 102.93 (C ᎐CC H CF trans to N); 102.67 (᎐C C H CF
᎐
α
6
4
3
6
4
3
trans to N); 57.82 (N–CH2); 23.36 (CH2); 19.07 (CH2); 13.53
(CH3, NBu4); m/z = 710 (MϪ; 100%); ΛM (acetone): 93 molϪ1
cm2 ΩϪ1.
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐CC H N-2) ] 6
᎐
4
5
4
2
[Pt(bzq)(µ-Cl)]2 (0.25 g, 0.306 mmol) was added to a solution
2 I. R. Whittal, A. M. MacDonag and M. G. Hunphrey,
Adv. Organomet. Chem., 1998, 42, 291.
᎐
containing 10 equiv. of the lithiated ligand (HC᎐CC H N-2,
᎐
5
4
3 (a) I. Ara, J. R. Berenguer, E. Eguizabal, J. Forniés, J. Gómez,
E. Lalinde and J. M. Saez-Rocher, Organometallics, 2000, 19, 4385;
(b) V. W. W. Yam, K. L. Yu, K. M. C. Wong and K. K. Cheung,
Organometallics, 2001, 20, 721; (c) V. W. W. Yam, P. K. Y. Yeung,
L. P. Chan, W.-M. Kwok, D. L. Phillips, K. L. Yu, R. W.-K. Wong,
H. Yan and Q. J. Meng, Organometallics, 1998, 17, 2590; (d ) C. L.
Choi, Y. F. Chen, C. Yip, D. L. Phillips and V. W. W. Yam,
Organometallics, 2000, 19, 3192; (e) R. D’Amato, A. Furlani,
M. Colapietro, G. Portalone, M. Casalboni, M. Falconeri and
M. V. Ruso, J. Organomet. Chem., 2001, 627, 13; ( f ) C. W. Chan,
L. K. Cheng and C. M. Che, Coord. Chem Rev., 1994, 132, 87.
4 M. H. Kahara and S. Takahash, J. Mater. Chem., 1992, 2, 43;
D. W. Bruce, in Inorganic Materials, ed. D. W. Bruce and D. O’Hare,
Wiley, Chichester, 1996.
5 N. Chawdhury, A. Köhler, R. H. Friend, W. Y. Wong, J. Lewis,
M. Younus, P. R. Raithby, T. C. Corcoran, M. R. A. Al-Mandhary
and M. S. Shan, J. Chem. Phys., 1999, 110, 4963 and references
therein; N. J. Long, A. J. P. White, D. J. Williams and M. Younus,
J. Organomet. Chem., 2002, 649, 94 and references therein; F. Takei,
H. Hayashi, K. Onitsuka, N. Kobayashi and S. Takahashi,
Angew. Chem., Int. Ed., 2001, 40, 4092.
0.308 mL, 3.06 mmol, and n-BuLi 1.91 mL, 3.06 mmol) in ether
(30 mL) at Ϫ78 ЊC. The reaction mixture was allowed to warm
slowly to room temperature (ca. 2.5 h) and then evaporated to
dryness. The remaining steps were identical to the procedure
described for 5, using 0.197 g, 0.611 mmol of (NBu4)Br in
deoxygenated H2O complex 6 precipitated as a yellow solid
(0.31g, 62%); (Found: C, 62.78; H, 6.57; N, 6.56. C43H52N4Pt
requires C, 62.98; H, 6.39; N, 6.82%); νmax/cmϪ1 (C᎐C) 2110vs
᎐
᎐
and 2086vs (Nujol). δH (CD3COCD3, J/Hz): 10.13 (dd, J = 5.1,
1, 3J(Pt–H) = 27 H2, bzq); 8.65 (dd, J = 6.9, 1.3, 3J(Pt–H) = 35
H9, bzq); 8.51 (dd, J = 7.1, 1, H4, bzq); 8.39 (m, 2H, H6, 2-Py)
7.8 (d, J = 8.7, H5, bzq); 7.65 (m, H6,3, bzq); 7.54 (m, 4H, H7,8,
bzq and 2 H4, 2-Py); 7.32 (d, 2H, H3, 2-Py); 7.00 (m, 2H, H5,
2-Py); 3.53 (m, NCH2, NBu4); 1.72 (m, –CH2–, NBu4); 1.27
(q, –CH2–, NBu4); 0.79 (t, –CH3, NBu4). The low solubility of
this complex at low temperature precludes its characteris-
ation by 13C NMR spectroscopy; m/z = 577 (MϪ,100%). ΛM
(acetone): 81 molϪ1 cm2 ΩϪ1.
6 T. B. Peters, J. C. Bohling, A. M. Arif and J. A. Gladysz,
Organometallics, 1999, 18, 3261; W. Morh, J. Stahl, F. Hampel and
J. A. Gladysz, Inorg. Chem., 2001, 40, 3263; W. Y. Wong, G. L. Lu,
K. F. Ng, K. H. Choi and Z. Lin, J. Chem. Soc., Dalton Trans., 2001,
3250.
7 M. I. Bruce, K. Costuas, J. F. Halet, B. C. Hall, P. J. Low,
B. K. Nicholson, B. W. Skelton and A. J. White, J. Chem. Soc.,
Dalton Trans., 2002, 383; J. A. Whiteford, C. V. Lu and P. J. Stang,
J. Am. Chem Soc., 1997, 119, 2524; S. M. AlQuasidi, K. J. Galat,
M. Chai, D. G. Ray, P. L. Rinaldi, C. A. Tessier and W. J. Youngs,
J. Am. Chem. Soc., 1998, 120, 12149; E. Bosch and C. L. Barnes,
Organometallics, 2000, 19, 5522.
8 M. Hissler, A. Harriman, A. Khatyr and R. Ziessel, Chem. Eur. J.,
1999, 5, 3366; V. W. W. Yam, C. H. Tao, L. Zhang, K. M. C. Wong
and K. K. Cheung, Organometallics, 2001, 20, 453; S. Leininger and
P. J. Stang, Organometallics, 1998, 17, 3981.
9 K. Onitsuka, M. Fujimoto, N. Ohshiro and S. Takahashi, Angew.
Chem., Int. Ed., 1999, 38, 689; K. Onitsuka, A. Luchi, M. Fujimoto
and S. Takahashi, Chem. Commun., 2001, 741; R. Ziessel,
M. Hissler, A. El-ghayoury and A. Harriman, Coord. Chem. Rev.,
1998, 178–180, 1251.
10 For some recent work see: (a) M. D. Meijer, A. W. Kleij,
B. S. Willinas, D. Ellis, M. Lutz, A. L. Speck, G. P. M. van Klink
and G. van Koten, Organometallics, 2002, 21, 264; (b) J. Brooks,
Y. Babayan, S. Lamansky, P. I. Djorovich, I. Tsyba, R. Bau and
M. E. Thompson, Inorg. Chem., 2002, 41, 3055 and references
therein; (c) G. Minghetti, A. Doppin, S. Stoccoro, A. Zucca,
M. A. Cinellu, M. Manassero and M. Sansoni, Eur. J. Inorg. Chem.,
2002, 431; (d ) D. Song, Q. Wu, A. Hook, I. Kozin and S. Wang,
Organometallics, 2001, 20, 4683; (e) L. Wei, M. C. W. Chan,
K. K. Cheung and C. M. Che, Organometallics, 2001, 20, 2477;
᎐
᎐
᎐
Synthesis of (NBu )[Pt(bzq)(C᎐CC H C᎐CC H ) ] 7
᎐
4
6
4
6
5 2
᎐
᎐
᎐
To a solution containing 8 equiv. of LiC᎐CC H C᎐CPh (1.987
᎐
6
4
mmol) in Et2O (30 mL, Ϫ40 ЊC) was added [Pt(bzq)(µ-Cl)]2
(0.203 g, 0.248 mmol) and the mixture was allowed to reach
room temperature. Once at room temperature, the mixture was
stirred for 2 h and then evaporated to dryness. The resulting
residue was extracted with a cold mixture of i-PrOH and
EtOH, filtered and treated with (NBu4)Br (0.200 g, 0.62 mmol)
affording 7 as a yellow solid (0.153 g, 31%); (Found: C, 71.91;
H, 6.47; N, 2.67. C61H62N2Pt requires C, 71.95; H, 6.14; N,
2.75%); νmax/cmϪ1 (C᎐C) 2209s, 2098s and 2074s (Nujol).
᎐
᎐
δH (CD3COCD3, J/Hz): 10.11 (d, J = 4.6, 3J(Pt–H) = 26.8, H2);
8.59 (d, J = 4.6, 3J(Pt–H) = 31, H9); 8.51 (d, J = 7.8, H4); 7.81 (d,
J = 8.7, H5); 7.67 (m); 7.64 (m); 7.59 (m), 7.54 (H3, H6–8, 6H,
C6H4, Ph); 7.42 (m, 12H, C6H4, Ph); 3.43 (m, NCH2, NBu4);
1.68 (m, –CH2–, NBu4); 1.28 (q, –CH2–, NBu4); 0.83 (t, –CH3,
NBu4). δC{1H} (CDCl3, J/Hz, 233 K): 162.4 (C10); 157.46 (C12);
149.88 (C2); 143.42 (C11); 136.16 (C4); 134.45 (C9); 133.11–
130.89 (C13,14, C6H4, Ph); 129.65 (C7,8); 129.29 (C7,8); 128.26–
127.93 (C6H4, Ph); 126.6 (C13,14); 123.07 (C6H4, Ph); 122.5 (C5,6);
121.13 (C3); 120.37 (C5,6); 117.89 (C6H4, Ph); 117.57(C6H4, Ph);
᎐
106.71, 103.79, 102.55 (C ᎐C C H ); 90.11, 90.02, 89.40, 89.32
᎐
α
β
6
4
᎐
(C H C᎐CPh); 57.77 (N–CH ); 23.38 (CH ); 19.09 (CH ); 13.55
(CH3, NBu4). MS ES(Ϫ): molecular peak not observed. ΛM
(acetone): 96 molϪ1 cm2 ΩϪ1.
᎐
6
4
2
2
2
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
829

View Article Online
( f ) K. E. Dungey, B. D. Thompson, N. A. P. Kane-Macguire and
L. L. Wright, Inorg. Chem., 2000, 39, 5192; (g) D. K. C. Tears and
D. R. MacMillin, Coord. Chem. Rev., 2001, 211, 195; (h) C. P.
Newman, G. W. V. Cave, M. Wong, W. Errinton, N. W. Alcock and
J. P. Rourke, J. Chem. Soc., Dalton Trans., 2001, 2678; (i) S. W. Lai,
M. C. W. Chan, T. C. Cheung, S. M. Peng and C. M. Che,
Inorg. Chem., 1999, 38, 4046; (j) W. B. Connick, D. Geiger and
R. Eisenberg, Inorg. Chem., 1999, 38, 3264; (k) G. Arena,
G. Galogero, S. Campagna, L. M. Scolaro, V. Ricevuto and
R. Romeo, Inorg. Chem., 1998, 37, 2763; (l ) G. Y. Zheng, D. P.
Rillema, J. Depriest and C. Woods, Inorg. Chem., 1998, 37, 3588;
(m) M. V. Kulikova, K. P. Balashev, P. I. Kvam and J. Songstad,
Russ. J. Gen. Chem., 2000, 70, 163 and references therein;
(n) V. Balzani, A. Juris, M. Venturi, S. Campagna and S. Serroni,
Chem. Rev., 1996, 96, 759; (o) G. R. Newkome, W. E. Puckett,
V. K. Gupta and G. E. Kiefer, Chem. Rev., 1986, 86, 451; (p) A. D.
Ryabov, Chem. Rev., 1990, 90, 403; (q) I. Omae, Coord. Chem. Rev.,
1988, 83, 137.
Berenguer, J. Forniés, E. Lalinde, F. Martínez and M. Moreno,
Organometallics, 1996, 15, 1820; (e) For a review see: ref. 1(d).
19 (a) I. Ara, J. R. Berenguer, J. Forniés and E. Lalinde, Organo-
metallics, 1997, 16, 3921; (b) I. Ara, J. R. Berenguer, E. Eguizabal,
J. Forniés, E. Lalinde, A. Martín and F. Martínez, Organometallics,
1998, 17, 478; (c) I. Ara, J. R. Berenguer, E. Eguizábal, J. Forniés,
E. Lalinde and F. Martínez, Organometallics, 1999, 18, 4344;
(d ) J. R. Berenguer, E. Eguizabal, L. R. Falvello, J. Forniés,
E. Lalinde and A. Martín, Organometallics, 2000, 19, 490; (e) I. Ara,
J. R. Berenguer, E. Eguizabal, J. Forniés and E. Lalinde,
Organometallics, 2001, 20, 2686.
20 (a) I. Ara, J. R. Berenguer, J. Forniés, J. Gómez, E. Lalinde,
A. Martín and R. Merino, Inorg. Chem., 1997, 36, 6461; (b) I. Ara,
J. Forniés, J. Gómez, E. Lalinde, R. Merino and M. T. Moreno,
Inorg. Chem. Commun., 1999, 2, 62; (c) J. P. H. Chartmant,
J. Forniés, J. Gómez, E. Lalinde, R. Merino and M. T Moreno,
Organometallics, 1999, 18, 3353; (d ) J. P. H. Chartmant, L. R.
Falvello, J. Forniés, J. Gómez, E. Lalinde, M. T. Moreno, A. G.
Orpen and A. Rueda, Chem. Commun., 1999, 2045; (e) I. Ara,
J. Forniés, J. Gómez, E. Lalinde and M. T. Moreno, Organometallics,
2000, 19, 3133; ( f ) J. Forniés, J. Gómez, E. Lalinde and M. T.
Moreno, Inorg. Chem., 2001, 40, 5415; (g) J. R. Berenguer, J. Forniés,
J. Gómez, E. Lalinde and M. T. Moreno, Organometallics, 2001, 20,
4847.
21 P. Jolliet, M. Gianini, A. von Zelewsky, G. Bernardinelly and
H. Stoeckli-Evans, Inorg. Chem., 1996, 35, 4883.
22 J. R. Berenguer, J. Forniés, E. Lalinde and F. Martinez,
Organometallics, 1996, 15, 4537.
23 (a) L. Chassot, E. Muller and A. von Zelewski, Inorg. Chem., 1984,
23, 4249; (b) M. Ghedini, D. Pucci, A. Crispini and G. Barberio,
Organometallics, 1999, 18, 2116; (c) J. De Priest, G. Y. Zheng,
N. Goswami, D. M. Eichhorn, C. Woods and D. P. Rillema,
Inorg. Chem., 2000, 39, 1955; (d ) J. De Priest, G. Y. Zheng,
C. Woods, D. P. Rillema, N. A. Mikirova and M. E. Zandler,
Inorg. Chim. Acta, 1997, 264, 287.
24 J. van Slageren, A. Klein and S. Zalisv, Coord. Chem. Rev., 2002, 239,
193 and references therein.
25 J. A. Zuleta, J. M. Bevilacqua, D. M. Proserpio, P. D. Harvey and
R. Eisenberg, J. Am. Chem. Soc., 1992, 31, 2396; S. D. Cummings
and R. Eisenberg, J. Am. Chem. Soc., 1996, 118, 1949; T. M. Cocker
and R. E. Bachman, Inorg. Chem., 2001, 40, 1550.
26 J. N. G. Demas and A. Crosby, J. Phys. Chem., 1971, 75, 991.
27 P. S. Pregosin and F. Wombacher, J. Organomet. Chem., 1991, 418,
249.
28 S. Takahashi, Y. Kuroyama, K. Sonogashira and N. Hagihara,
Synthesis, 1980, 627.
29 Gaussian 98 (Revision A.11), M. J. Frisch, G. W. Trucks,
H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman,
V. G. Zakrzewski, J. A. Montgomery, Jr., R. E. Stratmann,
J. C. Burant, S. Dapprich, J. M. Millam, A. D. Daniels, K. N. Kudin,
M. C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi,
B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski,
G. A. Petersson, P. Y. Ayala, Q. Cui, K. Morokuma, P. Salvador,
J. J. Dannenberg, D. K. Malick, A. D. Rabuck, K. Raghavachari,
J. B. Foresman, J. Cioslowski, J. V. Ortiz, A. G. Baboul, B. B.
Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi,
R. Gomperts, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham,
C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill,
B. Johnson, W. Chen, M. W. Wong, J. L. Andres, C. Gonzalez,
M. Head-Gordon, E. S. Replogle and J. A. Pople, Gaussian, Inc.,
Pittsburgh PA, 2001.
30 C. Lee, W. Yang and R. G. Parr, Phys. Rev. B, 1988, 37, 785.
31 (a) P. J. Hay and W. R. Wadt, J. Chem. Phys., 1985, 82, 270;
(b) W. R. Wadt and P. J. Hay, J. Chem. Phys., 1985, 82, 284;
(c) P. J. Hay and W. R. Wadt, J. Chem. Phys., 1985, 82, 299.
32 G. M. Sheldrick, SHELX-97, a program for the refinement of
crystal structures, University of Göttingen, Göttingen, Germany,
1997.
11 For alkynyl cycloplatinate complexes see: (a) W. Lu, B. X. Mi,
M. C. W. Chan, Z. Hui, N. Zhu, S. T. Lee and C. M. Che,
Chem. Commun., 2002, 206; (b) S. Back, R. A. Gossage, M. Luzt,
I. del Rio, A. L. Spek, H. Lang and G. van Koten, Organo-
metallics, 2000, 19, 3296; (c) S. Back, M. Albrecht, A. L. Speck,
G. Rheinwald, H. Lang and G. van Koten, Organometallics,
2001, 20, 1024; (d ) J. W. Hoogervost, C. J. Elsevier, M. Luzt and
A. Speck, Organometallics, 2001, 20, 4437; (e) C. J. McAdam,
E. J. Blackie, J. L. Morgan, S. A. Mole, B. H. Robinson and
J. Simpson, J. Chem. Soc., Dalton Trans., 2001, 2362; ( f ) S. L. James,
G. Verspui, A. L. Speck and G. van Koten, Chem. Commun., 1996,
1309.
12 For alkynyl diimine compounds see: (a) S. C. Chan, M. C. W. Chan,
Y. Wang, C. M. Che, K. K. Cheung and N. Zhu, Chem. Eur. J., 2001,
7, 4180; (b) J. E. McGarrah, Y.-J. Kim, M. Hissler and R. Eisenberg,
Inorg. Chem., 2001, 40, 4510; (c) C. E. Whittle, J. A. Weinstein,
M. W. George and K. S. Schanze, Inorg. Chem., 2001, 40, 4053;
(d ) M. Hissler, W. B. Connick, D. K. Geiger, J. E. McGarrah,
D. Lipa, R. J. Lachicotte and R. Eisenberg, Inorg. Chem., 2000, 39,
447; (e) Y. Y. Ng, C. M. Che and S. M. Peng, New J. Chem., 1996, 20,
781; ( f ) S. L. James, M. Younus, P. R. Raithby and J. Lewis,
J. Organomet. Chem., 1997, 543, 233; (g) C. J. Adams, S. L. James,
X. Liu, P. R. Raithby and L. J. Yellowlees, J. Chem. Soc.,
Dalton Trans., 2000, 63; (h) Y. Y. Ng, C. M. Che and S. M. Peng,
New J. Chem., 1996, 20, 781.
13 For alkynyl terpyridyl complexes see: V. W. W. Yam, R. P. L. Tang,
K. M. C. Wong and K. K. Cheung, Organometallics, 2001, 20, 4076.
14 D. Sandirini, M. Maestri, V. Balzani, L. Chassot and A. von
Zelewsky, J. Am. Chem. Soc., 1987, 109, 7720.
15 H. Kunkely and A. Vogler, J. Am. Chem. Soc., 1990, 112, 5625;
C. W. Chan, M. Maestri, V. Balzani, C. Deuschel-Cornioley and
A. von Zelewsky, Adv. Photochem., 1992, 17, 1; V. H. Houlding
and V. M. Miskoswski, Coord. Chem. Rev., 1991, 111, 145;
W. B. Connick, L. M. Henling, R. E. Marsh and H. B. Gray,
Inorg. Chem., 1996, 35, 261; G. Y. Zheng and D. P. Rillema,
Inorg. Chem., 1998, 37, 1392; S. W. Lai, H. W. Lam, W. Lu,
K. K. Cheung and C. M. Che, Organometallics, 2002, 21, 226.
See also ref. 3(f).
16 M. Hissler, J. E. McGarrah, W. B. Connick, D. K. Geiger,
S. D. Cummings and R. Eisenberg, Coord. Chem. Rev., 2000, 208,
115; W. Paw, S. D. Cummings, M. A. Mansour, W. B. Connick,
D. K. Geiger and R. Eisenberg, Coord. Chem. Rev., 1998, 171,
125; J. A. Bailey, M. G. Hill, R. E. Marsh, V. M. Miskowski,
W. P. Schaefer and H. B. Gray, Inorg. Chem., 1995, 34, 4591.
17 K. P. Balashev, M. V. Puzyk, V. S. Kotlyar and M. V. Kulikova,
Coord. Chem. Rev., 1997, 159, 109; C. A. Craig, F. O. Garces,
R. J. Watts, R. Palmans and A. J. Frank, Coord. Chem. Rev., 1990,
152, 193.
18 (a) P. Espinet, J. Forniés, F. Martínez, M. Tomás, E. Lalinde,
M. T. Moreno, A. Ruíz and A. J. Welch, J. Chem. Soc.,
Dalton Trans., 1990, 791; (b) J. Forniés, E. Lalinde, A. Martín and
M. T. Moreno, J Chem. Soc., Dalton Trans., 1994, 135; (c) P. Espinet,
J. Forniés, F. Martínez, M. Sotés, E. Lalinde, M. T. Moreno, A. Ruíz
and A. J. Welch, J. Organomet. Chem., 1991, 403, 253; (d ) J. R.
33 Z. Otwinowski and W. Minor, in Methods in Enzymology,
C. W. Carter, Jr. and R. M. Sweet, Eds., Academic Press, New York,
1997, vol. 276A, p. 307.
34 R. H. Blessing, Acta Crystallogr., Sect. A, 1995, 51, 33.
D a l t o n T r a n s . , 2 0 0 3 , 8 2 2 – 8 3 0
830