Synthesis of di-, tri- and tetranuclear platinum(II) and copper(I) acetylide complexes

Article abstract of DOI:10.1016/j.jorganchem.2007.06.034

Heterobimetallic {cis-[Pt](μ-σ,π-C{triple bond, long}CPh)₂}[Cu(N{triple bond, long}CMe)]BF₄ (3a: [Pt] = (bipy)Pt, bipy = 2,2′-bipyridine; 3b: [Pt] = (bipy′)Pt, bipy′ = 4,4′-dimethyl-2,2′-bipyridine) is accessible by the reaction of cis-[Pt](C{triple bond, long}CPh)₂ (1a: [Pt] = (bipy)Pt, 1b: [Pt] = (bipy′)Pt]) with [Cu(N{triple bond, long}CMe)₄]BF₄ (2). Substitution of N{triple bond, long}CMe by PPh₃ (4) can be realized by the reaction of 3a with 4, whereby [{cis-[Pt](μ-σ,π-C{triple bond, long}CPh)₂}Cu(PPh₃)]BF₄ (5) is formed. On prolonged stirring of 3 and 5, respectively, N{triple bond, long}CMe and PPh₃ are eliminated and tetrametallic {[{cis-[Pt](η²-C{triple bond, long}CPh)₂}Cu]₂}(BF₄)₂ (6) is produced. Addition of an excess of N{triple bond, long}CMe to 6 gives heterobimetallic 3a. When instead of N{triple bond, long}CMe or PPh₃ chelating molecules such as bipy (7) are reacted with 3a then the heterobimetallic π-tweezer molecule [{cis-[Pt](μ-σ,π-C{triple bond, long}CPh)₂}Cu(bipy)]BF₄ (8) is formed. Treatment of 8 with another equivalent of 7 produced [Cu(bipy₂)]BF₄ (9) along with [Pt](C{triple bond, long}CPh)₂. However, when 3b is reacted with 1b in a 1:1 molar ratio then 10 and 11 of general composition [{[Pt](C{triple bond, long}CPh)₂}₂Cu]BF₄ are formed. These species are isomers and only differ in the binding of the PhC{triple bond, long}C units to copper(I). A possible mechanism for the formation of 10 and 11 is presented. The solid state structures of 6, 10 and 11 are reported. In 11 the [{cis-[Pt](μ-σ,π-C{triple bond, long}CPh)₂}₂Cu]⁺ building block is set-up by two nearly orthogonal positioned bis(alkynyl) platinum units which are connected by a Cu(I) ion, whereby the four carbon-carbon triple bonds are unsymmetrical coordinated to Cu(I). In trimetallic 10 two cis-[Pt](C{triple bond, long}CPh)₂ units are bridged by a copper(I) center, however, only one of the two PhC{triple bond, long}C ligands of individual cis-[Pt](C{triple bond, long}CPh)₂ fragments is η²-coordinated to Cu(I) giving rise to the formation of a [(η²-C{triple bond, long}CPh)₂Cu]⁺ moiety with a linear alkyne-copper-alkyne arrangement (alkyne = midpoint of the C{triple bond, long}C triple bond). In 6 two almost parallel oriented [Pt](C{triple bond, long}CPh)₂ planes are linked by two copper(I) ions, whereby two individual PhC{triple bond, long}C units, one associated with each Pt building block, are symmetrically π-coordinated to Cu.

Full text of DOI:10.1016/j.jorganchem.2007.06.034

Journal of Organometallic Chemistry 692 (2007) 4168–4176
www.elsevier.com/locate/jorganchem
Synthesis of di-, tri- and tetranuclear platinum(II) and copper(I)
acetylide complexes
*
´
Heinrich Lang , Petra Zoufala, Sami Klaib, Amaya del Villar, Gerd Rheinwald
Technische Universita¨t Chemnitz, Fakulta¨t fu¨r Naturwissenschaften, Institut fu¨r Chemie, Lehrstuhl fu¨r Anorganische Chemie,
Straße der Nationen 62, 09111 Chemnitz, Germany
Received 4 May 2007; received in revised form 15 June 2007; accepted 20 June 2007
Available online 27 June 2007
Abstract
Heterobimetallic {cis-[Pt](l-r,p-C„CPh)2}[Cu(N„CMe)]BF4 (3a: [Pt] = (bipy)Pt, bipy = 2,20-bipyridine; 3b: [Pt] = (bipy0)Pt,
bipy0 = 4,40-dimethyl-2,20-bipyridine) is accessible by the reaction of cis-[Pt](C„CPh)2 (1a: [Pt] = (bipy)Pt, 1b: [Pt] = (bipy0)Pt]) with
[Cu(N„CMe)4]BF4 (2). Substitution of N„CMe by PPh3 (4) can be realized by the reaction of 3a with 4, whereby [{cis-[Pt](l-r,p-
C„CPh)2}Cu(PPh3)]BF4 (5) is formed. On prolonged stirring of 3 and 5, respectively, N„CMe and PPh3 are eliminated and tetrame-
tallic {[{cis-[Pt](g2-C„CPh)2}Cu]2}(BF4)2 (6) is produced. Addition of an excess of N„CMe to 6 gives heterobimetallic 3a.
When instead of N„CMe or PPh3 chelating molecules such as bipy (7) are reacted with 3a then the heterobimetallic p-tweezer mol-
ecule [{cis-[Pt](l-r,p-C„CPh)2}Cu(bipy)]BF4 (8) is formed. Treatment of 8 with another equivalent of 7 produced [Cu(bipy2)]BF4 (9)
along with [Pt](C„CPh)2. However, when 3b is reacted with 1b in a 1:1 molar ratio then 10 and 11 of general composition
[{[Pt](C„CPh)2}2Cu]BF4 are formed. These species are isomers and only differ in the binding of the PhC„C units to copper(I). A pos-
sible mechanism for the formation of 10 and 11 is presented.
The solid state structures of 6, 10 and 11 are reported. In 11 the [{cis-[Pt](l-r,p-C„CPh)2}2Cu]+ building block is set-up by two
nearly orthogonal positioned bis(alkynyl) platinum units which are connected by a Cu(I) ion, whereby the four carbon–carbon triple
bonds are unsymmetrical coordinated to Cu(I). In trimetallic 10 two cis-[Pt](C„CPh)2 units are bridged by a copper(I) center, however,
only one of the two PhC„C ligands of individual cis-[Pt](C„CPh)2 fragments is g2-coordinated to Cu(I) giving rise to the formation of
a [(g2-C„CPh)2Cu]+ moiety with a linear alkyne–copper–alkyne arrangement (alkyne = midpoint of the C„C triple bond). In 6 two
almost parallel oriented [Pt](C„CPh)2 planes are linked by two copper(I) ions, whereby two individual PhC„C units, one associated
with each Pt building block, are symmetrically p-coordinated to Cu.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Platinum; Copper; Alkyne; Chelate; Multiheterometallic; X-ray structure; Mechanism
1. Introduction
R = singly-bonded inorganic, organic or organometallic
group; X = singly- or chelate-bonded inorganic or organic
ligand) the bis(alkynyl) titanocene fragment acts as an
organometallic chelating ligand (organometallic p-tweezer)
to stabilize a low-valent CuX moiety. Such complexes
allow to study intramolecular electron transfer, since the
remote early (titanium) and late (copper) transition metals
are spanned by r- and p-coordinated alkynyls [4]. They
also can be used as catalytic active species in homogeneous
catalysis to study, for example, copper(I)-assisted organo-
transfer reactions and olefine-isomerizations [5].
Recently, the reaction chemistry of organometallic che-
lating ligands, based on bis(alkynyl) titanocenes, toward
different inorganic and organic copper(I) salts was reported
[1–3]. In the thus formed heterobimetallic {[Ti](l-r,p-
C„CR)2}CuX assemblies ([Ti] = (g5-C5H4SiMe3)2Ti, . . .;
*
Corresponding author. Tel.: +49 371 531 21210; fax: +49 371 531
21219.
E-mail address: heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.06.034

H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
4169
In contrast, the reaction chemistry of group-11 salts
toward bis(alkynyl) transition metal complexes other than
[Ti](C„CR)2 is only less studied [1,2,6]. Among them,
bis(alkynyl) platinum complexes are of interest, since they
feature a square-planar structure around the d8-configurated
group-10 metal which differs from the tetrahedral coordina-
tion sphere of the group-4 metal atoms titanium, zirconium
and hafnium (d0), respectively. This structural difference
should significantly reflect on the chemistry of such species.
We here describe the synthesis and reaction chemistry of
[{cis-[Pt](l-r,p-C„CPh)2}Cu(N„CMe)]BF4 and [{cis-
as 3a. Complexes 3a and 3b are stable in the solid state and
can be handled in air without significant decomposition. In
contrast, the isostructural platinum(II)–silver(I) species
[{cis-[Pt](l-r,p-C„CPh)2}Ag(N„CMe)]BF4 are more
reactive, i.e. they decompose on exposure to sunlight and
air on formation of metallic silver [7].
In heterobimetallic 3a and 3b the organometallic chelate
cis-[Pt](C„CPh)2 stabilizes the low-valent [Cu(N„CMe)]+
fragment by the g2-coordination of both PhC„C ligands
to copper. As a result thereof, a 16-valence electron count
of the [(g2-C„CPh)2Cu(N„CMe)]+ unit is most likely, a
most favoured structural motif in organometallic p-tweezer
chemistry [1].
In 3a or 3b the acetonitrile ligand is only weakly-coordi-
nated to copper(I) as it could be shown by addition of
Lewis-bases L (L = PPh3, bipy, cis-[Pt](C„CPh)2). For
example, when equimolar amounts of PPh3 (4) were added
to 3a a color change from yellow over orange to orange-
brown took place. After appropriate work-up, tetrametallic
{cis-[Pt](g2-C„CPh)2Cu}2(BF4)2 (6) could be isolated in
good yield (Section 4, Scheme 1).
[Pt](C„CPh)2Cu}2](BF4)2
([Pt] = (bipy)Pt,
bipy = 2,
20-bipyridine; [Pt] = (bipy0)Pt, bipy0 = 4,40-dimethyl-2,
20-bipyridine).
2. Results and discussion
A straightforward synthesis method to prepare heterobi-
metallic platinum(II)–copper(I) tweezer complexes of type
[{cis-[Pt](l-r,p-C„CPh)2}Cu(N„CMe)]BF4 (3a, [Pt] =
(bipy)Pt, bipy = 2,20-bipyridine; 3b, [Pt] = (bipy0)Pt,
bipy0 = 4,40-dimethyl-2,20-bipyridine) is given by the reac-
tion of cis-[Pt](C„CPh)2 (1) with [Cu(N„CMe)4]BF4 (2)
in a 1:1 molar ratio in dichloromethane as solvent at
25 ꢁC (Eq. (1)) [6n].
Within the reaction of 3a with 4 presumably the hetero-
bimetallc organometallic p-tweezer [{cis-[Pt](l-r,p-
C„CPh)2}Cu(PPh3)]BF4 (5) is formed at first in which
PPh3 is datively-bonded to Cu(I). However, it appeared
that this species is not stable in solution and dimerizes on
elimination of PPh3 to give tetrametallic 6 (Scheme 1).
Complexes similar to 5 could lately be isolated in tita-
nium(IV)–copper(I) and titanium(IV)–silver(I) p-tweezer
chemistry. [1] There it was found that depending on the
donor–acceptor capacity of the Lewis-base L, reversible
coordination adducts of type [{[Ti](l-r,p-C„CR)2}M(L)]
+
BF4
-
Me
C
N
Ph
Cu
[Cu(N≡CMe)4]BF4
(2)
C
C
Ph
C
C
C
C
C
C
[Pt]
[Pt]
- 3 N≡CMe
Ph
Ph
X/{[Ti](l-r,p-C„CR) }MX are formed ([Ti] = (g5-C5H4
1a: [Pt] = (bipy)Pt
1b: [Pt] = (bipy´)Pt
3a: [Pt] = (bipy)Pt
3b: [Pt] = (bipy´)Pt
2
SiMe3)2Ti; M = Cu, Ag; R = singly-bonded inorganic,
organic or organometallic ligand; X = BF4, PF6, ClO4;
L ¼ NR03; PR30 ; PðOR0Þ3; . . .Þ [1,8]. Complex 6 can be
transferred to the starting material 3a on its reaction with
an 5-fold excess of N„CMe (Scheme 1).
bipy
bipy´ =
,
=
N
N
N
N
ð1Þ
The copper(I) ion in 3a and 3b possesses coordination
number 3. Thus, it should be possible to reach coordina-
tion number four at copper by adding, for example,
organic or organometallic chelating molecules such as bipy
After appropriate work-up, 3a and 3b could be isolated
as yellow solids which dissolve in polar organic solvents
such as dichloromethane and tetrahydrofuran, whereby
the bipy0 derivative 3b shows a somewhat better solubility
+
BF4
PPh3
-
Cu
Ph
C
C
C
C
2
[Pt]
Ph
4
( )
2PPh3
≡
-2 N CMe
-2 PPh3
5
2+
Ph
-
+
BF4
2BF4
C
-
C
Me
[Pt]
[Pt]
C
C
C
N
Ph
Cu
Cu
Cu
Ph
≡
N
CMe(exc.)
C
C
C
C
[Pt]
2
Ph
Ph
C
C
C
C
Ph
3a
6
Scheme 1. Synthesis of 6 from 3a and 4.

4170
H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
and cis-[Pt](C„CPh)2, respectively. Treatment of 3a with
one equivalent of bipy (7) produced the platinum(II)–cop-
per(I) complex [{cis-[Pt](l-r,p-C„CPh)2}Cu(bipy)]BF4
(8) in dichlormethane at 25 ꢁC (Eq. (2)). In 8 the copper(I)
ion possesses a pseudo-tetrahedral surrounding, set up by
the chelating ligands bipy and cis-[Pt](C„CPh)2 (Eq. (2)).
tion of 9 from 1a can be carried out by crystallization
from dichloromethane-n-pentane mixtures at 0 ꢁC. Due
to its lower solubility, complex 9 precipitates at first. Both
complexes were characterized by IR and H NMR spec-
troscopy, ESI-TOF mass spectrometry and elemental
analysis.
1
In attempt to synthesize a coordination complex in
which a copper(I) ion is embedded between two cis-
[Pt](C„CPh)2 entities, a structural motif which is typical
for 11, we reacted 3b with 1b in a 1:1 molar ratio (Eq.
(3)). Within this reaction, the acetonitrile ligand is replaced
by the organometallic chelate cis-[Pt](C„CPh)2 to give
[{cis-[Pt](C„CPh)(g2-C„CPh)}2Cu]BF4 (10) (Eq. (3)).
After appropriate work-up, complex 10 could be isolated
as an orange solid in quantitative yield.
+
+
BF4
-
BF4
-
Me
C
N
N
N
Cu
Cu
C
bipy(7)
Ph
Ph
C
C
C
C
-N≡CMe
[Pt]
C
C
[Pt]
Ph
C
Ph
8
3a
ð2Þ
+
-
Ph
BF4
C
C
+
C
C
+
[Pt]
Ph
-
Me
BF4
Ph
C
Ph
-
BF4
N
C
C
Ph
1b
C
+
Δ
C
T
Cu
Cu
ð3Þ
Ph
[Pt]
Cu
[Pt]
C
C
C
C
C
≡
-N CMe
C
[Pt]
C
C
C
C
C
Ph
Ph
[Pt]
Ph
C
Ph
10
3b
11
Heterobimetallic red 8 only dissolves in polar organic
solvents and is not stable for a longer period of time,
either in the solid state nor in solution. On elimination
of cis-[Pt](C„CPh)2 (1a) the bipy-copper complex [Cu(bi-
py)2]BF4 (9) is formed. This clearly shows that bipy is a
better chelating ligand for copper(I) then 1a. The forma-
tion of 1a and 9 from 8 can be enhanced, when 8 is
reacted with a further equivalent of bipy (7). The separa-
In 10 two cis-oriented [Pt](C„CPh)2 building blocks are
connected by a copper(I) ion, whereby one of the two
phenylethynyl ligands of individual cis-[Pt](C„CPh)2 units
is g2-coordinated to Cu(I). A linear C2–Cu–C2 entity
(C2 = midpoint of the C„C units) is formed. The respec-
tive [(g2-C„CPh)2Cu]+ moieties count to 18-valence
electrons.
+
Ph
C
C
[Pt]
C
C
Ph
Cu
Ph
C
C
+
[Pt]
+
C
+
BF4
Ph
C
Ph
-
C
C
Me
Ph
C
C
C
C
C
N
[Pt]
Ph
[Pt]
Ph
12
C
C
Ph
Ph
Cu
+ 1
Ph
Ph
C
C
C
C
-N≡CMe
Cu
[Pt]
Cu
Ph
C
C
C
[Pt]
[Pt]
13
C
3
Ph
+
Ph
Ph
10
C
C
C
C
C
C
[Pt]
Cu
[Pt]
C
C
Ph
Ph
11
Scheme 2. Possible mechanism for the formation of 11 by treatment of 1 with 3.

H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
4171
In the synthesis of 10 it is necessary to keep the reaction
time below 3 h, and to run the reaction between 0 and
20 ꢁC. Otherwise 10 starts to isomerize to give 11 (Eq.
(3)). On prolonged stirring of 10 at 25 ꢁC (12 h), complex
11 is formed in quantitative yield and can be isolated in
form of bright orange crystals. These studies show that
10 can be considered as an intermediate in the formation
of 11. In 11 all PhC„C units are g2-coordinated to cop-
per(I), a structural motif, which is characteristic in tita-
nium-, palladium- and platinum-p-tweezer chemistry [1,2].
A possible reaction sequence for the formation of 11 by
starting from 1 and 3 is presented in Scheme 2.
Complex 10, produced by the reaction of 1 with 3 (vide
supra), rearranges in solution to give most probably 12, a
compound in which the platinum and copper metal atoms
are connected by l,r-bridged phenylethynyl ligands
(Scheme 2). Complexes similar to 12 could be isolated
and characterized, i.e. [{(cis-[Pt](l-r-C„CPh)2)2}Ag]X
(X = ClO4,BF6) [1,6,7]. From platinum–silver chemistry
it is known that such molecules rearrange in solution to
give complexes of structural type 13 (Scheme 2) [1,6,7]. In
13, one of the two [cis-Pt(C„CPh)2Cu] units possess, as
typical for 12, l,r-bridging PhC„C ligands, while the sec-
ond [cis-Pt(C„CPh)2Cu] moiety shows a tweezer-type
arrangement with l-r,p-coordinating phenylacetylides.
Trimetallic 13 isomerizes at 25 ꢁC to produce 11 (Scheme
2) [1a,1c]. The proposed mechanism and hence, the forma-
tion of 11 from 10 via intermediates 12 and 13, relates to
isostructural platinum–silver complexes, which could be
isolated and characterized by single X-ray structure analy-
sis [1,6,7]. The formation of the appropriate isostructural
Pt–Ag complexes can be realized by controlling the temper-
ature and the reaction time, respectively. That such a mech-
anism may also play a key role in platinum–copper
chemistry is related to the observation that during the reac-
tion of 1b with 3b different colors (yellow-orange-red-
orange) appear. However, no further species could be
Fig. 2. ORTEP plot (50% probability level) of the molecular structure of
10 with the atom numbering scheme. The counter-ion BF4 and the
ꢀ
hydrogen atoms are omitted for clarity. Cu(1)–Pt(1) 2.7642(6), Cu(1)–C(1)
2.066(16), Cu(1)–C(2) 2.494(15), Pt(1)–N(1) 2.073(14), Pt(1)–N(2)
2.055(11), Pt(1)–C(1) 1.960(14), Pt(1)–C(9) 2.01(2), C(1)–C(2) 1.201(18),
C(2)–C(3) 1.477(19), C(9)–C(10) 1.15(2), C(10)–C(11) 1.43(2); Pt(1)–C(1)–
C(2) 177.4(15), Pt(1)–C(9)–C(10) 177.8(19), N(1)–Pt(1)–N(2) 79.1(5),
C(1)–Pt(1)–C(9) 86.5(6), C(1)–Cu(1)–C(2) 28.6(5), N(1)–Pt(1)–C(9)
175.8(6), N(2)–Pt(1)–C(1) 176.7(6), C(1)–C(2)–C(3) 168.7(18), C(9)–
C(10)–C(11) 176(2), N(1)–Pt(1)–C(1) 97.7(6), N(1)–Pt(1)–Cu(1) 118.2(3),
Pt(1)–Cu(1)–C(1) 45.1(4), Pt(1)–Cu(1)–C(2) 73.7(3), Cu(1)–Pt(1)–C(9)
65.0(5), Cu(1)–Pt(1)–C(1) 48.3(5), N(2)–Pt(1)–C(9) 96.7(5), N(2)–Pt(1)–
Cu(1) 134.2(3).
isolated, except 10 and 11, even not, when the reaction tem-
perature and the reaction time were systematically varied.
Complexes 3, 6 and 8–11 were characterized by elemen-
1
tal analysis and spectroscopy (IR, H NMR) (Section 4).
From 6, 10 and 11 the solid state structure was determined
by single X-ray structure determination.
Single crystals of 6, 10 and 11 could be grown by diffu-
sion of n-pentane into a dichloromethane solution contain-
ing 6, 10 or 11 at 25 ꢁC (6) or 0 ꢁC (10, 11). The molecular
structures of 6, 10 and 11 are shown in Figs. 1 (6), 2 (10) and
3 (11). Geometric details for 6 and 11 are listed in Tables 1
and 2. The crystal and intensity collection data for com-
plexes 6, 10 and 11 are summarized in Table 3 (Section 4).
Complex 6 crystallizes in the monoclinic space group
C2/m (Fig. 1). The half molecule is symmetry generated
by a mirror plane (x, ꢀy, z; ꢀx + 1/2) passing through
the Pt1 and Pt2 atoms; symmetry generated atoms are indi-
cated with the suffix A (Fig. 1).
Two almost parallel oriented cis-[Pt](C„CPh)2 planes
are linked by the copper(I) ions Cu(1) and Cu(1a) with
the platinum atoms Pt(1) and Pt(2) on the same site (the
bond distances are Pt1–Cu1 2.969(3) and Pt2–Cu1
˚
2.934(2) A), whereby two individual PhC„C ligands, one
associated with each platinum fragment, are symmetrical
Fig. 1. ORTEP plot (30% probability level) of the molecular structure of 6
with the atom numbering scheme. The counter-ions BF4ꢀ, the molecule
CH2Cl2 and the hydrogen atoms are omitted for clarity.
g2-coordinated to Cu(1). The bond distances are Cu(1)–
˚
C(1) 1.992(19), Cu(1)–C(9) 1.993(19) A for the Ca carbons

4172
H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
Table 2
Selected bond distances (A) and angles (ꢁ) for 11
a
˚
Bond distances
Pt(1)–Cu(1)
Pt(2)–Cu(1)
Pt(1)–C(1)
Pt(1)–C(9)
Pt(2)–C(27)
Pt(2)–C(35)
Pt(1)–N(1)
Pt(1)–N(2)
Pt(2)–N(3)
Pt(2)–N(4)
Cu(1)–C(1)
Cu(1)–C(2)
Cu(1)–C(9)
Cu(1)–C(10)
3.0405(11)
3.1824(11)
1.971(8)
1.960(9)
1.987(8)
1.991(8)
2.059(7)
2.075(7)
2.078(7)
2.071(6)
2.296(8)
2.549(8)
2.263(8)
2.509(9)
C(1)–C(2)
C(2)–C(3)
1.227(11)
1.450(11)
1.222(12)
1.448(12)
1.228(11)
1.456(11)
1.204(11)
1.450(11)
2.208(7)
2.282(8)
2.224(8)
2.457(8)
C(9)–C(10)
C(10)–C(11)
C(27)–C(28)
C(28)–C(29)
C(35)–C(36)
C(36)–C(37)
Cu(1)–C(27)
Cu(1)–C(28)
Cu(1)–C(35)
Cu(1)–C(36)
Angles
N(1)–Pt(1)–N(2)
N(3)–Pt(2)–N(4)
C(1)–Pt(1)–C(9)
C(27)–Pt(2)–C(35)
N(1)–Pt(1)–C(1)
N(1)–Pt(1)–C(9)
N(2)–Pt(1)–C(1)
N(2)–Pt(1)–C(9)
C(9)–C(10)–C(11)
a
79.4(3)
78.9(3)
88.0(3)
86.9(3)
96.0(3)
175.2(3)
173.8(3)
96.5(3)
169.1(9)
N(3)–Pt(2)–C(27)
N(3)–Pt(2)–C(35)
N(4)–Pt(2)–C(27)
N(4)–Pt(2)–C(35)
Pt(1)–C(1)–C(2)
Pt(1)–C(9)–C(10)
Pt(2)–C(27)–C(28)
Pt(2)–C(35)–C(36)
C(1)–C(2)–C(3)
98.5(3)
174.6(3)
176.0(3)
95.7(3)
173.0(7)
174.9(8)
175.8(7)
175.1(7)
173.4(8)
Fig. 3. ORTEP plot (50% probability leveꢀl) of the molecular structure of
11 with the atom numbering scheme. BF4 as counter-ion, the hydrogen
atoms and the CH2Cl2 molecule are omitted for clarity.
Table 1
a
˚
Selected bond distances (A) and angles (ꢁ) for 6
The estimated standard deviations of the last significant digit(s) are
shown in parenthesis.
Bond distances
Pt(1)–N(1)
Pt(1)–C(1)
C(1)–C(2)
Cu(1)–C(1)
Cu(1)–C(2)
Pt(1)–Cu(1)
2.055(18)
1.951(17)
1.225(10)
1.992(19)
2.15(2)
Pt(2)–Cu(1)
Cu(1)–C(9)
Cu(1)–C(10)
Pt(2)–N(2)
Pt(2)–C(9)
C(9)–C(10)
2.934(2)
1.993(19)
2.15(2)
2.051(18)
1.93(2)
However, due to the crystal quality (thin plates) the molec-
ular structure of 10 is only presented for comparison and
selected bond distances and angles are given for a rough
estimate.
2.969(3)
1.26(3)
Angles
The molecular structure of 10 involves two cis-oriented
(bipy0)Pt(C„CPh)2 units which are spanned by Cu(1).
Each of the two cis-[Pt](C„CPh)2 entities coordinate with
one alkynyl group (C(1)–C(2), C(1a)–C(2a)) toward Cu1,
thus Cu1 acts as a connecting ion. The phenylethynyl
ligands are thereby unsymmetrically g2-coordinated to
Pt(1)–C(1)–C(2)
C(1)–C(2)–C(3)
Pt(2)–C(9)–C(10)
C(9)–C(10)–C(11)
C(1)–Cu(1)–C(2)
C(1)–Cu(1)–C(9)
C(9)–Cu(1)–C(10)
C(2)–Cu(1)–C(9)
C(2)–Cu(1)–C(10)
a
173(2)
173(3)
176.5(18)
174(2)
33.2(8)
165.5(8)
34.9(8)
160.9(9)
126.0(9)
C(1)–Cu(1)–C(10)
Pt(1)–Cu(1)–Pt(2)
N(1)–Pt(1)–C(1)
N(1)–Pt(1)–Cu(1)
N(2)–Pt(2)–C(9)
N(2)–Pt(2)–Cu(1)
C(1)–Pt(1)–C(1A)
C(9)–Pt(1)–C(9A)
158.9(9)
83.82(7)
96.5(8)
97.2(8)
95.8(5)
94.2(5)
89.4(12)
85.5(12)
˚
Cu(1) (Cu(1)–C(1) 2.066(16), Cu(1)–C(2) 2.494(15) A)
(Fig. 2). The two platinum atoms are opposite positioned
to each other, whereby the Pt(1)–Cu(1)–Pt(1a) atoms are
linear oriented (Fig. 2). Following trends are found: (i)
the g2-coordinated carbon–carbon triple bonds C(1)–C(2)
are somewhat longer than the respective non-coordinated
acetylides C(9)–C(10), (ii) the Pt(1)–C(1)–C(2) and Pt(1)–
C(9)–C(10) angles are almost identical, and (iii) through
the p-bonding of C(1)–C(2) to Cu(1) the Pt(1)–C(1)–C(2)
unit is almost not affected (177.4(15)ꢁ), while the C(1)–
C(2)–C(3) moiety is cis-bent by 168.7(18)ꢁ.
The estimated standard deviations of the last significant digit(s) are
shown in parenthesis.
˚
and Cu(1)–C(2)/Cu(1)–C(10) 2.15(2) A for the Cb atoms
(PtCa„CbPh) (Table 1). Similar structural arrangements
are found, for example, in silver(I) transition metal chemis-
try [9]. The dihedral angle formed by the calculated mean
planes I (Pt(1), C(1), C(2) and N(1)) and II (Pt(2), C(9),
C(10) and N(2)) is 5.03(1)ꢁ (r.m.s. deviation of fitted
˚
atoms = 0.0075 (plane I) and 0.0187 A (plane II)). The
The solid state structure of 11 is illustrated in Fig. 3.
Complex 11 crystallizes in yellow blocks in the triclinic
Pt–C and Pt–N bond distances and angles are typical for
this type of complexes [1,2,6]. All other bond distances
and angles (Table 1) are in the range of expected values
and are characteristic for such groups.
Complex 10 crystallizes in the monoclinic space group
C2/c and possesses a centre of inversion at Cu(1)
(1 ꢀ x + 1/2, ꢀy + 1/2, ꢀz) (Fig. 2). The symmetry gener-
ated atoms are indicated with the suffix A (Fig. 2).
ꢀ
space group P1. In 11, the copper(I) ion Cu(1) unsymmet-
rically spans two almost orthogonal positioned cis-
[Pt](C„CPh)2 units, thus reaching coordination number
4 at copper and hence, following an 18-valence electron-
count.
Two coordination modes of the cis-[Pt](C„CPh)2 units
toward Cu1 in 11 are observed. The Pt2-containing Pt(2),

H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
4173
Table 3
Crystal and intensity collection data for 6, 10 and 11
Compound
6
10
11
Formula weight
Empirical formula
Chemical formula
Crystal system
Space group
1492.65
C53H38B2Cl2 Cu2F8N4Pt2
[C52H36Cu2N4Pt2](BF4)2 Æ CH2Cl2
Monoclinic
C2/m
14.3164(5)
24.6301(9)
15.8504(5)
5286.4(3)
–
108.942(2)
–
1.875
656.74
C28H22B0.50Cu0.50F2N2Pt
[C56H44CuN4Pt2](BF4)
Monoclinic
C2/c
20.8525(9)
9.4531(5)
23.2561(12)
4583.1(4)
–
91.3100(10)
–
1342.30
C53H38BCl2CuF4N4Pt2
[C52H36CuN4Pt2](BF4). CH2Cl2
Triclinic
ꢀ
P1
˚
a (A)
11.04910(10)
12.6557(2)
18.1036(2)
2497.37(5)
89.8340(10)
80.6930(10)
88.5420(10)
1.785
˚
b (A)
˚
c (A)
3
˚
V (A )
a (ꢁ)
b (ꢁ)
c (ꢁ)
qcalc (g cmꢀ3
)
1.904
Crystal dimension (mm)
Z
0.50 · 0.10 · 0.05
4
0.08 · 0.06 · 0.02
8
0.3 · 0.2 · 0.1
2
Diffractometer model
Radiation (k, A)
Bruker SMART CCD
0.71073
Bruker SMART CCD
0.71073
Bruker SMART CCD
0.71073
˚
Max., min. transmission
Absorption coefficient (l, mmꢀ1
Temperature (K)
Scan mode
0.7456, 0.1465
6.239
173(2)
0.681298, 0.534729
6.611
173(2)
0.424224, 0.221867
6.171
173(2)
)
x-scans
x-scans
x-scans
Scan range (ꢁ)
Index ranges
1.65–25.00
ꢀ14 6 h 6 17, ꢀ28 6 k 6 29,
ꢀ18 6 l 6 13
13634
1.75–26.00
ꢀ22 6 h 6 25, ꢀ8 6 k 6 11,
ꢀ13 6 l 6 28
7352
1.61–26.00
ꢀ13 6 h 6 13, ꢀ15 6 k 6 15,
ꢀ16 6 l 6 22
14585
Total reflections
Unique reflections
4590
3771
9641
Observed reflections [I P 32r(I)]
Refined parameters
Ra1, wR2a [I P 2r(I)]
Ra1, wRa2 (all data)
Weighted schematic parameters (a/b)
Rint
2546
336
0.0965, 0.1978
0.1791, 0.2398
0.1086/12.6701
0.1144
2213
243
0.0774, 0.1078
0.1586, 0.1296
0.0/0.0
0.1158
1.181, ꢀ1.963
7132
604
0.0478, 0.1179
0.0684, 0.1269
0.0715/0.0
0.0346
8.010, ꢀ2.400b
Max., min. peak in final Fourier map 5.827, ꢀ3.310b
ꢀ3
˚
(e A
)
Goodness-of-fit on F2b
1.113
0.964
0.995
P
P
P
P
P
a
2
2
R1 = [ (||Fo| ꢀ |Fc|)/ |Fo|]; wR2 = [ (w(Fo ꢀ Fc2)2)/ (wFo4)]1/2; P = [Fo2 + 2Fc2]/3c; S = [ w(Fo ꢀ Fc2)2]/(n ꢀ p)1/2; n = number of reflections,
p = parameters used; w = 1/[r2(Fo2) + (aP)2 + bP].
b
ꢀ3
;
˚
The highest unrefined electron density peaks (Q peaks) for 6 are located at distances below 131 pm around Pt: (d(Pt(1)–Q(1)) = 115.5 pm; 5.83 e A
d(Pt(2)–Q(2)) = 130.2 pm; 3.87 e A ) and for 11 below 100 pm around Pt: (d(Pt(1)–Q(1)) = 99.6 pm; 8.01 e A ; d(Pt(2)–Q(2)) = 92.4 pm; 1.70 e Aꢀ3).
According to Refs. [13,14], this might be observed for heavy atoms for which remaining electron density peaks with ca. 10% of the electron density of the
heavy atom are expected to be observed at distances between 60 and 120 pm.
ꢀ3
ꢀ3
˚
˚
˚
˚
C(27), C(28), C(35) and C(36) unit coordinates Cu1 in
plane, while the Pt1-containing Pt(1), C(1), C(2), C(9)
and C(10) entity coordinates Cu1 out-of-plane. Thus, the
highest deviation from a calculated mean plane (plane II)
of all non-hydrogen atoms for the Pt2-containing unit
(including Cu1, but excluding the two Ph groups; r.m.s.
Cu(1)–C(27) 2.208(7), and Cu(1)–C(35) 2.224 (8) A for
the Ca carbons as well as Cu(1)–C(2) 2.549(8), Cu(1)–
C(10) 2.509(9), Cu(1)–C(28) 2.282(8) and Cu(1)–C(36)
˚
2.457(8) A for the Cb atoms (PtCa„CbPh) (Table 2).
Within the Pt2Cu segment Cu(1) is more symmetrically
bound to Pt(1) than to Pt(2) (Table 2). The same phenom-
enum is observed in trimetallic {[(PPh3)2Pt(l-r,p-C„
CPh)2]2Ag}ClO4, [{[Ti](l-r,p-C„CR)2}2M]X (M = Cu,
Ag; X = BF4, PF6, ClO4; R = Ph, Fc) [1,2,6]. If one com-
pares the bond distances of the copper–carbon acetylides
with the data typical in heterobimetallic platinum–copper
tweezer chemistry, it is most obvious that in 11 longer
bonds are found. This indicates that in 11 the interaction
of the four acetylides with Cu(1) is weaker, when compared
with {cis-[Pt](l-r,p-C„CPh)2}CuX [1,6].
˚
deviation of fitted atoms = 0.0150 A) is observed for C35
˚
(0.0266(7) A). Above a calculated mean plane (plane I)
of all non-hydrogen atoms for the Pt1-containing unit
(excluding Cu and the two Ph groups, r.m.s. deviation of
˚
fitted atoms = 0.0390 A) Cu1 is located at a distance of
˚
1.0637(7) A. The dihedral angle formed by planes I and
II is 88.33(2)ꢁ.
Both bis(alkynyl) platinum building blocks Pt(C„
CPh)2 are acting as organometallic chelates toward Cu(1)
(Fig. 3, Table 2), whereby the carbon–carbon triple bonds
are asymmetric g2-coordinated. Typical copper–carbon
distances are Cu(1)–C(1) 2.296(8), Cu(1)–C(9) 2.263(8),
Through the g2-coordination of the PhC„C ligands to
Cu(1), a bond-lengthening of the C„C triple bonds from
˚
1.201(6) and 1.211(6) A in 1a [9] to 1.227(11) (C(1)–C(2)),

4174
H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
1.222(12) (C(9)–C(10)), 1.228(11) (C(27)–C(28)) and
1.204(11) A (C(35)–C(36)) in 11 is found (Table 2). This
were recorded at 67.890 MHz (internal standard, relative
to CDCl3, d 77.16 and CD2Cl2, d 53.50); 31P{1H} NMR were
recorded at 101.202 MHz in CDCl3 with P(OMe)3 as exter-
nal standard (d 139.0, relative to 85% H3PO4, d 0.00). Chem-
ical shifts are reported in d units (ppm) downfield from
tetramethylsilane with the solvent signal as reference. Melt-
ing points were determined using analytically pure samples,
sealed off in nitrogen-purged capillaries with a Gallenkamp
MFB 595 010 melting point apparatus. Microanalyses were
performed by the Organic Department at Chemnitz, Univer-
sity of Technology and the Institute of Organic Chemistry at
the University of Heidelberg.
˚
corresponds to the observation generally made in transi-
tion metal chemistry by changing from free, non-coordi-
nated alkynes to g2-coordinated acetylides. Due to the
p-bonding of C„C to Cu(1), the linear Pt–C„C–CPh units
in 1a are cis-bent, which is evidenced by considering the
corresponding Pt–C„C and C„C–CPh angles (Table 2).
Due to steric reasons and, due to the tweezer effect of the
bis(alkynyl) platinum units, the angles at Pt(1) and Pt(2)
differ from those ones typical for square-planar Pt com-
plexes and are in the range of 78–99ꢁ (Table 2). The Pt–C
and Pt–N bond distances are typical for this type of com-
plexes [1].
4.2. General remarks
Furthermore, it is found that copper(1) is only displaced
˚
by 1.0637(7) A from the Pt(1) coordination plane, while it
Compounds 1a, 1b [9] and [Cu(N„CMe)4]BF4 [10] were
prepared by published procedures. All other chemicals
were purchased by commercial suppliers and were used
as received.
˚
is with 0.2565(7) A above the ideal Pt(2) plane oriented
(Fig. 3). The platinum–copper distances with 3.0405(11)
and 3.1824(11) A show that no Pt–Cu interactions exist.
˚
3. Conclusion
4.3. Synthesis of 3a
Within this study the synthesis and properties of [{cis-
[Pt](l-r,p-C„CPh)2}Cu(N„CMe)]BF4 ([Pt] = (bipy)Pt,
(bipy0)Pt; bipy = 2,20-bipyridine, bipy0 = 4,40-dimethyl-
2,20-bipyridine) is discussed. The reaction chemistry of the
latter molecule toward diverse 2- and 4-electron donor
molecules L such as PPh3, bipy and [Pt](C„CPh)2 is
reported. Depending on L different (isomeric) complexes
are formed. Typical species are {cis-[Pt][(l-r,p-C„
To 225 mg (0.406 mmol) of 1a dissolved in dichloro-
methane (125 mL), molecule 2 (127 mg, 0.406 mmol) was
added in a single portion at 25 ꢁC, whereby a color change
from yellow to orange and again to yellow was observed.
After 12 h of stirring at this temperature the solvent was
decanted from the yellow precipitate and was washed with
n-pentane (2 · 10 mL). The remaining residue was tried in
oil-pump vacuum affording a yellow solid. Yield: 300 mg
(0.404 mmol, 99% based on 1a).
CPh)Cu]2}(BF4)2,
[{cis-[Pt](l-r,p-C„CPh)2}Cu(bipy)]-
BF4, [{cis-[Pt](C„CPh)(g2-C„CPh)}2Cu]BF4 and [{cis-
[Pt](l-r,p-C„CPh)2}2Cu]BF4. Furthermore, it could be
shown that depending on the temperature [{cis-[Pt](C„
CPh)(g2-C„CPh)}2Cu]BF4 isomerizes in solution via the
intermediate formation of [{cis-[Pt](l-r-C„CPh)2}2Cu]-
M.p. (ꢁC): 240 (decomp.). IR (KBr) [cmꢀ1]: mN„C 2289
(m), 2282 (w); mC„C 2028 (s), 1990 (sh); mB–F 1056 (vs).
1H NMR (d6-dmso): [d] 2.05 (s, 3H, CH3C„N), 7.1–7.3
(m, 6H, mH, pH/Ph), 7.46 (d, JHH ¼ 7:2 Hz, 4H, oH/
3
3
3
Ph), 7.84 (dd, JH5
¼ 5:9 Hz, JH5H4 ¼ 7:1 Hz, 2H, H5/
H6
3
BF4
and
[{cis-[Pt](l-r-C„CPh)2}Cu{[Pt](l-r,p-C„
bipy), 8.40 (dd, JH4H3 ¼ 8:1 Hz, 3J
¼ 7:1 Hz, 2H,
H4H5
4
H /bipy) 8.63 (d, JH3H4 ¼ 8:1 Hz, 2H, H3/bipy), 9.28 (d,
3
CPh)2}]BF4 to give trimetallic Pt2Cu [{cis-[Pt](l-r,p-C„
CPh)2}2Cu]BF4.
3J
¼ 5:9 Hz, 2H, H6/bipy). Anal. Calc. for
H6H5
C28H21N3PtCuBF4 (744.76): C, 45.16; H, 2.84; N, 5.63.
4. Experimental
Found: C, 44.96; H, 2.87; N, 5.24%.
4.1. General methods
4.4. Synthesis of 3b
All reactions were carried out in an atmosphere of puri-
fied nitrogen (O2 traces: CuO catalyst, BASF AG, Ludwig-
shafen, Germany; H2O traces: molecular sieve, 4 A, Roth
Complex 3b was prepared as described for the synthesis
of 3a (see above). Thus, 200 mg (0.349 mmol) of 1b were
reacted with 2 (109 mg, 0.349 mmol) in tetrahydrofuran
(125 mL). After appropriate work-up, complex 3b could
be isolated as a yellow solid in 270 mg (0.349 mmol,
100% based on 1b) yield.
˚
company) using standard Schlenk techniques. Solvents were
purified by distillation (n-hexane/n-pentane and dichloro-
methane: calcium hydride; benzene and toluene: sodium; tet-
rahydrofuran: sodium/benzophenone ketyl). FT-IR spectra
were recorded with a Perkin–Elmer FT-IR 1000 spectrome-
ter (KBr or as film between NaCl plates). NMR spectra were
recorded with a Bruker Avance 250 spectrometer operating
in the Fourier transform mode. 1H NMR spectra were
recorded at 250.123 MHz (internal standard, relative to
CDCl3, d 7.26 and CD2Cl2, d 5.32). 13C{1H} NMR spectra
M.p. (ꢁC): 220 (decomp.). IR (KBr) [cmꢀ1]: mN„C 2322
(m), 2291 (w); mC„C 2042 (s), 2027 (s), 1992 (sh); mB–F
1056 (vs). 1H NMR1 (d6-dmso): [d] 2.05 (s, 3H, CH3C„N),
1
The resonance signal for the CH3(bipy) protons is covered by the signal
of the d6-dmso solvent molecule.

H. Lang et al. / Journal of Organometallic Chemistry 692 (2007) 4168–4176
4175
m
p
3
7.2–7.3 (m, 6H, H, H/Ph), 7.44 (d, JHH ¼ 7:2 Hz, 4H,
25 ꢁC. After 12 h of stirring at this temperature all volatiles
were removed in oil-pump vacuum. Yield of 11: 221 mg
(0.176 mmol, 98% based on 1a).
0
o
H/Ph), 7.62 (d, JH5H6 ¼ 6:3 Hz, 2H, H5=bipy ), 8.44 (s,
3
0
0
2H, H3=bipy ), 9.04 (d, JH6H5 ¼ 6:3 Hz, 2H, H6=bipy ).
Anal. Calc. for C30H25N3PtCuBF4 (773.00): C, 46.61; H,
3.26; N, 5.43. Found: C, 46.36; H, 3.27; N, 5.15%.
3
From 10: Compound 1a (233 mg, 0.42 mmol) was dis-
solved in dichloromethane (50 mL) and 77 mg (0.35 mmol)
of 2 was added at 25 ꢁC. The reaction solution was stirred
for 12 h, whereas the color changed from yellow to brown.
75 mL of n-pentane were added and a greenish precipitate
formed. The thus obtained solid was dissolved in 10 mL of
dichloromethane. By a slow diffusion of n-pentane into this
solution gave yellow to orange colored crystals of 11.
Yield: 85 mg (0.064 mmol, 56% based on 1a).
4.5. Synthesis of 5 and 6
200 mg (0.286 mmol) of 3a were reacted with equimolar
amounts of PPh3 (4) in diethyl ether at 25 ꢁC. During the
course of the reaction the color of the reaction solution
turned from yellow to orange (formation of 5) and then
to orange-brown. After 24 h of stirring at this temperature
all volatiles were removed in oil-pump vacuum and the res-
idue was extracted with dichloromethane (20 mL). Evapo-
ration of the solvent in oil-pump vacuum gave 186 mg
(0.127 mmol, 95% based on 3a) of 6. Single crystals of 6
could be obtained by slow diffusion of n-pentane into a
dichloromethane solution containing 6 at 25 ꢁC.
M.p. (ꢁC): 229 (decomp.). IR (KBr) [cmꢀ1]: mC„C 2085,
1
2057; mB–F 1060. H NMR (CD3CN): [d] 7.2–7.3 (m, 6H,
m
p
o
3
H, H/Ph), 7.4–7.5 (m, 4H, H/Ph), 7.61 (pt, JHH ¼ 6:5
Hz, 2H, H5/bipy), 8.1–8.2 (m, 4H, H4, H3/bipy), 9.48 (d,
3JH6H5 ¼ 6:9 Hz, 2H, H6/bipy). Anal. Calc. for C52H36N4
Pt2CuBF4 Æ CH2Cl2 (1342.44): C, 47.42; H, 2.86 N, 4.17.
Found: C, 45.51; H, 3.30; N, 4.17%.
4.6. Synthesis of 8 and 9
4.9. Single X-ray structure analysis of 6, 10 and 11
200 mg (0.286 mmol) of 3a were reacted with one equiva-
lent of 7 in dichloromethane at 25 ꢁC. The reaction mixture
changed its color from yellow to orange (formation of 8).
Further addition of another equivalent of bipy produced a
red solution. Evaporation of all volatiles in oil-pump vacuum
yielded a red solid. Crystallization from a 1:1 dichlorometh-
ane-n-pentane mixture at 25 ꢁC gave red 9. On subsequent
cooling the remaining solution to 0 ꢁC pale yellow crystals
of 1a formed. Yield: 1a: 148 mg (0.286 mmol, 100% based
on 3a). 9: 124 mg (0.286 mmol, 100%).
The solid state structures of 6, 10 and 11 were deter-
mined by single crystal X-ray diffraction. Data collection
was performed on a Bruker axs SMART 1k with graphite
˚
monochromatized Mo Ka radiation (k = 0.71073 A). Crys-
tallographic data of 6 and 11 are given in Table 3, while the
data for 10, due to the crystal quality, are only given for
comparison in Fig. 2. The structures were solved by direct
methods using SHELXS-97 [11]. An empirical absorption cor-
rection was applied. The structures were refined by full-
matrix least-square procedures on F2 using SHELXL-97
[12]. All non-hydrogen atoms were refined anisotropically
and a riding model was employed in the refinement of
the hydrogen atom positions.
4.7. Synthesis of 10
To 3b (22 mg, 0.028 mmol) suspended in dichlorometh-
ane (25 mL) complex 1b (17 mg, 0.028 mmol) was added in
a single portion at 25 ꢁC, whereby a color change from red
to yellow was observed. After 3 h of stirring at this temper-
ature all volatiles were removed in oil-pump vacuum. The
orange residue was washed with n-pentane (2 · 5 mL).
Yield of 10: 36 mg (0.028 mmol, 100% based on 1b).
Orange single crystals could be grown from a saturated
10:1 dichloromethane-n-pentane mixture at 0 ꢁC.
5. Supplementary material
CCDC 645853, 645856 and 645854 contain the supple-
mentary crystallographic data for 6, 10 and 11. These data
can be obtained free of charge via http://www.ccdc.cam.a-
c.uk/conts/retrieving.html, or from the Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
M.p. (ꢁC): 228 (decomp.). IR (KBr) [cmꢀ1]: mC„C 2118
(s), 2033 (s); mB–F 1056 (vs). 1H NMR (d6-dmso)1: [d]
p
3
7.1–7.3 (m, 6H, mH, H/ Ph), 7.41 (d, JHH = 7.8 Hz, 4H,
oH/Ph), 7.58 (d, JH5H4 ¼ 5:4 Hz, 2H, H /bipy0), 8.40
5
3
Acknowledgements
3
6
3
(s, 2H, H /bipy0), 9.03 (d, JH6H5 ¼ 5:4 Hz, 2H, H /bipy0).
Anal. Calc. for C56H44N4Pt2CuBF4 (1313.52): C, 51.20;
H, 3.37; N, 4.26. Found: C, 50.97; H, 3.44; N, 4.45%.
The financial support from the Deutsche Forschungs-
gemeinschaft and the Fonds der Chemischen Industrie
have been essential throughout.
4.8. Synthesis of 11
References
Reaction of 1a with 3a: 100 mg (0.180 mmol) of 1a was
dissolved in dichloromethane (50 mL) and 134 mg
(0.180 mmol) of 3a was added in a single portion at
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