Wire like diplatinum, triplatinum, and tetraplatinum complexes featuring X[PtCCCCCCCC]mPtX segments; Iterative syntheses and functionalization for measurements of single molecule properties

Article abstract of DOI:10.1039/c9dt00870e

Reaction of (p-tol₃P)₂PtCl₂ and Me₃Sn(CC)₂SiMe₃ (1:1/THF/reflux) gives monosubstituted trans-Cl(p-tol₃P)₂Pt(CC)₂SiMe₃ (63%), which with wet n-Bu₄N⁺ F^- yields trans-Cl(p-tol₃P)₂Pt(CC)₂H (2, 96%). Hay oxidative homocoupling (O₂/CuCl/TMEDA) gives all-trans-Cl(p-tol₃P)₂Pt(CC)₄Pt(Pp-tol₃)₂Cl (3, 68%). Reaction of 3 and Me₃Sn(CC)₂SiMe₃ (1:1/rt) affords monosubstituted all-trans-Cl(p-tol₃P)₂Pt(CC)₄Pt(Pp-tol₃)₂(CC)₂SiMe₃ (46%), which is converted by a similar desilylation/homocoupling sequence to all-trans-Cl[(p-tol₃P)₂Pt(CC)₄]₃Pt(Pp-tol₃)₂Cl (7; 79%). Reaction of (p-tol₃P)₂PtCl₂ and excess H(CC)₂SiMe₃ (HNEt₂/cat. CuI) gives trans-Me₃Si(CC)₂Pt(Pp-tol₃)₂(CC)₂SiMe₃ (78%), which with wet n-Bu₄N⁺ F^- affords trans-H(CC)₂Pt(Pp-tol₃)₂(CC)₂H (96%). Hay oxidative cross coupling with 2 (1:4) gives all-trans-Cl[(p-tol₃P)₂Pt(CC)₄]₂Pt(Pp-tol₃)₂Cl (10, 36%) along with homocoupling product 3 (33%). Reaction of 3 and Me₃Sn(CC)₂SiMe₃ (1:2/rt) yields all-trans-Me₃Si(CC)₂(p-tol₃P)₂Pt(CC)₄Pt(Pp-tol₃)₂(CC)₂SiMe₃ (17, 77%), which with wet n-Bu₄N⁺ F^- gives all-trans-H(CC)₂(p-tol₃P)₂Pt(CC)₄Pt(Pp-tol₃)₂(CC)₂H (96%). Reaction of 3 and excess Me₃P gives all-trans-Cl(Me₃P)₂Pt(CC)₄Pt(PMe₃)₂Cl (4, 86%). A model reaction of trans-(p-tol)(p-tol₃P)₂PtCl and KSAc yields trans-(p-tol)(p-tol₃P)₂PtSAc (12, 75%). Similar reactions of 3, 7, 10, and 4 give all-trans-AcS[(R₃P)₂Pt(CC)₄]_nPt(PR₃)₂SAc (76-91%). The crystal structures of 3, 17, and 12 are determined. The first exhibits a chlorine-chlorine distance of 17.42 ?; those in 10 and 7 are estimated as 30.3 ? and 43.1 ?.

Full text of DOI:10.1039/c9dt00870e

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: J. A. Gladysz, Q.
Zheng, J. Schneider, H. Amini and F. Hampel, Dalton Trans., 2019, DOI: 10.1039/C9DT00870E.
This is an Accepted Manuscript, which has been through the
Volume 45 Number
1 7 January 2016 Pages 1–398
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
Accepted Manuscripts are published online shortly after
An international journal of inorganic chemistry
www.rsc.org/dalton
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

Page 1 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Wire Like Diplatinum, Triplatinum, and Tetraplatinum Complexes
Featuring X[PtCCCCCCCC]mPtX Segments; Iterative Syntheses
and Functionalization for Measurements of Single Molecule
Properties
‡a
¶a
b
a
Qinglin Zheng, Jakob Schneider, Hashem Amini, Frank Hampel, and John A.
a,b*
Gladysz
a
Institut für Organische Chemie and Interdisciplinary Center for Molecular Materials,
Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 42, 91054 Erlangen,
Germany
b
Department of Chemistry, Texas A&M University, PO Box 30012, College Station,
Texas 77842-3012, USA
E-mail: gladysz@mail.chem.tamu.edu
Abstract
Reaction of (p-tol P) PtCl
and Me Sn(CC) SiMe
(1:1/THF/reflux) gives
3
2
2
3
2
3
+
–
monosubstituted trans-Cl(p-tol P) Pt(CC) SiMe (63%), which with wet n-Bu N F
3
2
2
3
4
yields trans-Cl(p-tol P) Pt(CC) H (2, 96%). Hay oxidative homocoupling
3
2
2
(O /CuCl/TMEDA) gives all-trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) Cl (3, 68%). Reaction
2
3
2
4
3 2
of 3 and Me Sn(CC) SiMe
(1:1/rt) affords monosubstituted all-trans-Cl(p-
tol P) Pt(CC) Pt(Pp-tol ) (CC) SiMe (46%), which is converted by a similar
3
2
3
3
2
4
3 2
2
3
desilylation/homocoupling sequence to all-trans-Cl[(p-tol P) Pt(CC) ] Pt(Pp-tol ) Cl
3
2
4 3
3 2
(7; 79%). Reaction of (p-tol P) PtCl and excess H(CC) SiMe (HNEt /cat. CuI) gives
3
2
2
2
3
2
+
–
trans-Me Si(CC) Pt(Pp-tol ) (CC) SiMe (78%), which with wet n-Bu N F affords
3
2
3 2
2
3
4
trans-H(CC) Pt(Pp-tol ) (CC) H (96%). Hay oxidative cross coupling with 2 (1:4)
2
3 2
2
gives all-trans-Cl[(p-tol P) Pt(CC) ] Pt(Pp-tol ) Cl (10, 36%) along with homocoupling
3
2
4 2
3 2
product 3 (33%). Reaction of 3 and Me Sn(CC) SiMe (1:2/rt) yields all-trans-
3
2
3
Me Si(CC) (p-tol P) Pt(CC) Pt(Pp-tol ) (CC) SiMe (17, 77%), which with wet n-
3
2
3
2
4
3 2
2
3
+
–
Bu N
F
gives all-trans-H(CC) (p-tol P) Pt(CC) Pt(Pp-tol ) (CC) H (96%).
4
2 3 2 4 3 2 2
Reaction of 3 and excess Me P gives all-trans-Cl(Me P) Pt(CC) Pt(PMe ) Cl (4,
3
3
2
4
3 2
86%). A model reaction of trans-(p-tol)(p-tol P) PtCl and KSAc yields trans-(p-tol)(p-
3
2
tol P) PtSAc (12, 75%). Similar reactions of 3, 7, 10, and 4 give all-trans-
3
2
AcS[(R P) Pt(CC) ] Pt(PR ) SAc (76-91%). The crystal structures of 3, 17, and 12
3
2
4 n
3 2
are determined. The first exhibits a chlorine-chlorine distance of 17.42 Å; those in 10
and 7 are estimated as 30.3 Å and 43.1 Å.
†
Electronic supplementary information (ESI) available: Cyclic voltammogram traces.
CCDC 1899327 (3), 1898997 (17), and 1898998 (12). For ESI and crystallographic data
in CIF or other electronic format see DOI: 10.1039/c5sc03xxxx
‡
Present address: THOR Specialty Chemical Company Limited, 182 Jingang Ave., New
District, Zhenjiang, Jiangsu, 212132 PRC.

Dalton Transactions
Page 2 of 45
View Article Online
DOI: 10.1039/C9DT00870E
¶
Present address: Delmar Chemicals Inc., 9321 Rue Airlie, Montréal, QWC, H8R 2B2,
Canada
Key words: platinum, polyyne, phosphine, thioacetate, crystal structures, homocoupling
submitted to Dalton Transactions
-2-

Page 3 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Introduction
There has been great interest in compounds in which sp carbon chains span two
1
transition metals. In particular, polyynediyl moieties, -(CC) -, can be viewed as the
n
ultimate in unsaturated bridging organic ligands, as they can never be twisted out of
conjugation. As the field has developed, increased attention has been given to
compounds with more complex arrays of sp carbon chains. Some of these are of
2
interest with respect to molecular devices and materials properties, while others
3
possess a structural aesthetic and attract those drawn to synthetic challenges. Some
of the earliest practitioners in this field trained their sights on one dimensional polymers
4
4d,5
6
of the types Ia and Ib
(Figure 1), and second generation efforts included a few
6a
homologs with (CC) segments. More extensive attention has been given to arylene
3
4a,6,7
expanded analogs such as II,
which we note for the record but view any further
digression as beyond the scope of this study.
Figure 1. Previously synthesized polymers (I, II) and title complexes (III).
8
Efforts in our laboratory have focused on the elaboration of Re(CC) Re and
n
9
Pt(CC) Pt systems. These building blocks are available with chain lengths of up to
n
twenty eight sp carbon atoms, although as a side remark the current "record" is held by
10
purely organic compounds with bulky substituted trityl endgoups. We were attracted
to a related challenge, namely the synthesis of longitudinal arrays based upon -
4,6
L PtCCCCCCCC- repeat units. Despite the work on systems of the type I,
and
2
-3-

Dalton Transactions
Page 4 of 45
View Article Online
DOI: 10.1039/C9DT00870E
the collateral isolation of two trimetallic complexes with -L MCCCC- repeat units
2
4b
(discussion section), to our knowledge iterative synthetic strategies that afford families
of -[L M(CC) ] - species remain unknown. When such series are available, the
y
n m
gradual transition of physical and chemical properties to the macromolecular limit can
be mapped.
In this paper, we report efficient syntheses of such assemblies bearing two,
three, and four platinum atoms, each terminating in platinum-chloride bonds. We then
introduce thioacetate ligands at the termini, which can be transformed to the equivalent
11
of "alligator clips" for single molecule conductivity and other measurements. The first
12
series of reactions have been communicated,
but the second have never been
disclosed, despite a published investigation of the charge transport properties of one of
13
the sulfur containing complexes. Representative crystal structures are also described,
together with in depth analyses of spectroscopic and thermal properties. A detailed
investigation of the photophysical properties of the dichloride complexes has been
14
reported separately.
Results
1. Syntheses of Diplatinum Complexes. For syntheses of diplatinum polyynediyl
9
complexes L Pt(CC) PtL (IV), monofunctional monoplatinum building blocks such as
y
n
y
trans-Ar'(Ar P) PtCl suffice. Under appropriate conditions, the chloride ligands can be
3
2
replaced by a variety of alkynyl groups. The oxidative homocoupling of L Pt(CC) H
y
n/2
species then affords the target molecules IV, although the precursors are often
generated in situ due to rapidly decreasing stabilities when n > 2. In contrast, the
iterative synthesis of longitudinally extended homologs III requires difunctional platinum
building blocks, such as the dichloride complex trans-(Ar P) PtCl . However, at certain
3
2
2
stages monofunctionalizations are likely to be necessary. Thus, reactions with terminal
alkynes and diynes (1:1 mol ratios) were screened under conditions previously
employed for related monochloride complexes. Unfortunately, mixtures of bis(alkynyl),
-4-

Page 5 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
the desired monoalkynyl/monochloride, and unreacted dichloride complexes were
always obtained.
Accordingly, the previously reported unsymmetrical stannyl/silyl diyne
Me Sn(CC) SiMe was prepared by the sequential reaction of H(CC) SiMe with n-
3
2
3
2
3
15
BuLi and Me SnCl, as shown in Scheme 1. It was then combined (1:1 mol ratio) with
3
16
either cis- or trans-(p-tol P) PtCl in refluxing THF. Me SnCl elimination occurred in
3
2
2
3
preference to Me SiCl elimination to give the monosubstituted product trans-Cl(p-
3
17
tol P) Pt(CC) SiMe (1) in 63% yield after workup.
Indeed, reactions of other
3
2
2
3
platinum dichloride complexes L PtCl and the trimethylstannyl alkyne Me SnCCPh
2
2
3
18
give the monosubstitution products trans-ClL PtCCPh in good yields.
2
-5-

Dalton Transactions
Page 6 of 45
View Article Online
DOI: 10.1039/C9DT00870E
Scheme 1. Syntheses of diplatinum complexes.
Complex 1 and all other new compounds below were characterized by
1
13
1
31
1
microanalysis, NMR ( H,
spectrometry. The IR 
C{ H},
P{ H}) and IR spectroscopy, and mass
31
13
values and P NMR data are provided in Table 1, and
C
CC
NMR data are listed in Table 2. In all cases, trans stereochemistry could be assigned
1
19
based upon the diagnostic magnitudes of the J
values (2518-2615 Hz). Other
PPt
data are analyzed in the discussion section.
Complex 1 was elaborated to a diplatinum octatetraynediyl complex similarly to
9a,b
related trialkylsilylbutadiynyl adducts described earlier.
First, reaction with wet n-
+
–
Bu N F gave the butadiynyl complex trans-Cl(p-tol P) Pt(CC) H (2) in 96% yield.
4
3
2
2
-6-

Page 7 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Subsequent oxidative homocoupling under Hay conditions (O , CuCl, TMEDA,
2
20
acetone) afforded the target complex 3 (Scheme 1) as a yellow solid in 68% yield.
The thermal stabilities of 3 and all other octatetraynediyl complexes were characterized
by various measures as given in Table 3. Their UV-visible spectra were also recorded,
as summarized in Table 4 and depicted in Figure 2.
Figure 2. UV-visible spectra (for concentrations and  values, see Table 4).
The application of this family of compounds as "molecular wires" requires
introducing functionality that can effectively bind gold or another suitable surface or
11
break junction tip. Towards this end, moderately bulky cis triarylphosphine ligands
such as p-tol P may weaken the attachment. Thus, the feasibility of a "post synthetic
3
modification" for introducing smaller phosphines was tested. As shown in Scheme 1, 3
and Me P (4.8 equiv) were combined in CH Cl . After 1 h, workup gave the
3
2
2
tetrakis(trimethylphosphine) complex 4 (Scheme 1) in 86% yield.
2. Syntheses of Tri- and Tetraplatinum Complexes. It was next sought to
elaborate 3 to higher homologs by selectively introducing a single butadiynyl ligand. As
shown in Scheme 2, reaction with Me Sn(CC) SiMe (1.0 equiv) gave the
3
2
3
monosubstituted trimethylsilylbutadiynyl complex 5 (Scheme 2) in 46% yield after
chromatography. Presumably some disubstituted product also formed, but was removed
on the column. Next, a desilylation/homocoupling sequence analogous to that used to
convert 2 to 3 was carried out. This gave first the butadiynyl complex 6 (50%; Scheme
-7-

Dalton Transactions
Page 8 of 45
View Article Online
DOI: 10.1039/C9DT00870E
2) and then the tetraplatinum target (7; 48% or 24% from 5) as an orange solid.
Curiously, the desilylation of 5 was much slower than that of 1. When the conversion of
5 to 7 was carried out in a single pot without purification of the intermediate 6, the
overall yield improved to 79%.
Scheme 2. Synthesis of tetraplatinum complex 7.
To access the corresponding triplatinum species, a two-fold cross coupling was
envisioned as shown in Scheme 3. In a standard procedure for the formation of
21
platinum-alkynyl linkages, either cis- or trans-(p-tol P) PtCl was condensed with
3
2
2
16,17
excess H(CC) H in HNEt in the presence of CuI.
In both cases, workups gave
2
2
22
the bis(butadiynyl) complex trans-H(CC) Pt(Pp-tol ) (CC) H (8, 47%). However, a
2
3 2
2
two step procedure gave somewhat better overall yields. First, (p-tol P) PtCl and
3
2
2
H(CC) SiMe
were similarly condensed to give trans-Me Si(CC) Pt(Pp-
3 2
2
3
22
tol ) (CC) SiMe (9; 78%). Both trimethylsilyl groups could then be removed with
3 2
2
3
+
–
wet n-Bu N F to give 8 (96%). Next, in a one-pot sequence, 1 was similarly de-
4
-8-

Page 9 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
9a
silylated to 2, and Me SiCl was added to scavenge fluoride ion. Then 8 was added
3
(0.25 equiv or 1:4 mol ratio) and cross coupling effected under Hay conditions.
Chromatography gave the triplatinum target 10 (36% based upon 8; Scheme 3). Some
homocoupling product 3 also formed (33% based upon 1), but could be separated.
Scheme 3. Synthesis of the triplatinum complex 10.
3. Thioacetate complexes. Covalent connections to gold electrodes, as well as
the formation of self assembled monolayers on gold surfaces, are most commonly
11
effected using -SH groups. Since thiols can be prone to oxidation, they are often
generated in situ by basic hydrolyses or NaBH reductions of the corresponding
4
11,23,24
thioacetates.
Palladium halide complexes are known to readily react with
-9-

Dalton Transactions
Page 10 of 45
View Article Online
DOI: 10.1039/C9DT00870E
25
potassium thioacetate (KSAc) to give thioacetate complexes. Thus, a model reaction
9b
was carried out with the platinum chloride complex trans-(p-tol)(p-tol P) PtCl (11) as
3
2
shown in Scheme 4 (top). Workup gave the expected substitution product trans-(p-
tol)(p-tol P) Pt(SAc) (12) in 75% yield.
3
2
Pp-tol3
Pt Cl
Pp-tol3
Pp-tol3
Pt SAc
Pp-tol3
CH2Cl2
+
H3C
H3C
KSAc
(1.5
equiv)
12, 75%
11
3, 10, 7, or 4
CH2Cl2
KSAc (3 equiv)
KSAc = KSC(=O)CH3
Pp-tol3
AcS Pt
Pp-tol3
p-tol3P
C
C C C C C C C Pt SAc
p-tol3P
13, 91%
or
Pp-tol3
p-tol3P
Pp-tol3
AcS Pt C C C C C C C C Pt C C C C C C C C Pt SAc
Pp-tol3
Pp-tol3 p-tol3P
14, 86%
or
Pp-tol3
AcS Pt
Pp-tol3
p-tol3P
C C C C C C C Pt C C C C C C C C Pt C C C C C C C C Pt SAc
p-tol3P
Pp-tol3 p-tol3P
Pp-tol3
p-tol3P
C
15, 80%
or
PMe3
AcS Pt
PMe3
Me3P
C
C C C C C C C Pt SAc
Me3P
16, 76%
Scheme 4. Syntheses of thioacetate complexes.
Similar conditions were then applied to the di-, tri-, and tetraplatinum complexes
3, 10, and 7, as well as trimethylphosphine-substituted 4. As shown in Scheme 4
(bottom), the corresponding bis(thioacetate) complexes 13-16 were isolated in 76-91%
–1
yields. The IR 
bands were observed at 1613-1625 cm (m; Table 1), with those
C=O
for the homologous series 13-15 monotonically increasing with the number of repeat
–1
units m. The IR 
bands were found at 942-946 cm (m).
C-S
4. Other chemistry. In the course of developing the syntheses in Schemes 1-3 or
-10-

Page 11 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
exploring routes to still higher homologs, a number of other reactions were evaluated.
One dead end that merits emphasis is shown in Scheme 5. The reaction of the
diplatinum complex 3 and excess H(CC) SiMe was carried out under standard
2
3
conditions (cat. CuI/HNEt ) with the idea of replacing both chloride ligands with
2
trimethylsilylbutadiynyl groups. However, workup gave the monoplatinum complex 9, a
key building block in Scheme 3, in 77% yield. This indicates that platinum-polyynediyl
linkages can, under appropriate conditions, undergo net  bond metatheses with
terminal alkynes, and suggests a general way to deoligomerize any of the species III
back to monoplatinum complexes.
Scheme 5. Additional platinum-carbon bond forming reactions.
With regard to possible extension of the title series, 3 was treated with 2 equiv of
Me Sn(CC) SiMe under conditions similar to those used for the 1:1 reaction in
3
2
3
Scheme 3. As shown in Scheme 5, the expected disubstitution product 17 could be
-11-

Dalton Transactions
Page 12 of 45
View Article Online
DOI: 10.1039/C9DT00870E
isolated in 77% yield. Numerous efforts were made to selectively protodesilylate one of
the termini. However, satisfactory conditions were never found. Nonetheless, both
+
–
trimethylsilyl groups could be efficiently removed with wet n-Bu N F , affording 18
4
(Scheme 5) in 96% yield. The monosilylated intermediate would be an attractive
precursor to another tetraplatinum complex, and 18 is a potential monomer for oxidative
polymerizations that would yield higher homologs of the title complexes.
5. Other characterization. The diplatinum complexes 3 and 17 could both be
crystallized (the former as a diacetone solvate). The crystal structures were determined
as outlined in Table 5 and the experimental section. The molecular structures are
depicted in Figure 3, and key interatomic distances and bond angles are provided in
Table 6. In both cases, the sp carbon chains adopted S-shaped conformations
containing an inversion center. These features have also been seen in the structures of
1b
other tetraynes and higher polyynes. All bond lengths and angles were within the
1b
ranges found in related diplatinum complexes. The platinum-platinum distances were
12.750-12.833 Å, and the chlorine-chlorine distance in 3 was 17.422 Å. Although single
crystals of 10 and 7 could not be obtained, the chlorine-chlorine distances can be
estimated as 30.3 and 43.1 Å, respectively, using the platinum-platinum and platinum-
chlorine distances in 3.
-12-

Page 13 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Figure 3. Thermal ellipsoid plots (50% probability) of 3·(acetone) with the acetone molecules omitted
2
(top) and 17 (bottom).
Single crystals of the model thioacetate complex 12 could also be obtained, and
the structure was similarly determined. The results are given in Figure 4, and confirm
25
that none of the several alternative thioacetate coordination modes are operative. The
bond distances and angles about platinum and the thioacetate carbon atom are
unexceptional. All are in good agreement with those in two other platinum(II) thioacetate
complexes, both of which are dianionic (most pronounced difference: Pt-S 2.3793(7) Å
26
in 12 vs. 2.3048(4)-2.3312(4) Å in others).
Unfortunately, none of the other
thioacetate complexes in Scheme 4 could be crystallized.
Figure 4. Thermal ellipsoid plot (50% probability of 12. Key bond distances (Å) and angles (°): Pt-C
,
11
2.046(3); Pt-S, 2.3793(7); Pt-P , 2.3117(6); Pt-P , 2.3020(6); S-C, 1.745(3); CO, 1.213(4); C -Pt-S,
1
2
11
170.50(7); P -Pt-P , 172.92(2); Pt-S-C, 110.89(10); S-C-O, 125.2(2); O-C-C, 121.2(3).
1
2
-13-

Dalton Transactions
Page 14 of 45
View Article Online
DOI: 10.1039/C9DT00870E
Cyclic voltammograms of 3, 10, and 7 showed partially reversible one-electron
oxidations, as summarized in Table 7 and depicted in Figure s1 in the electronic
supplementary information (ESI). The i
values decreased with the Pt/C chain
c/a
sp
9a,b
length, as seen for several series of diplatinum polyynediyl complexes.
In contrast,
the corresponding thioacetate complexes did not show any appreciable anodic current
following the initial oxidation.
Discussion
1. Related complexes and synthetic methodology. As briefly noted in the
introduction, two trimetallic group 10 complexes with two butadiynediyl linkages have
4b
27
been previously reported, and their syntheses are shown in Scheme 6 (20, top). An
analogous route to our triplatinum complex 10 would be challenging due to the very
9a,b
poor stabilities of octatetraynyl (L M(CC) H) complexes, even at low temperatures.
y
4
Using other types of metal-carbon bond forming reactions, we have isolated an adduct
28
with a trans-Re(CC) Pd(CC) Re linkage, and some Au(CC) Ru(CC) Au species
2
2
n
n
2b
(n = 2-4) have been recently reported. Berke has synthesized tetrairon complexes
with Fe(CC) Fe(CC) Fe(CC) Fe backbones, as well as diron analogs, and
2
2
2
demonstrated that stable junctions to gold STM tips can be generated from Me Sn-
3
30
(CC) Fe moieties.
2
-14-

Page 15 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Scheme 6. Additional relevant reactions or complexes.
Schemes 1-3 provide reasonably efficient routes to the title complexes, capped
by the tetraplatinum adduct 7 with a linear array of 28 platinum and sp carbon atoms.
However, extensions to higher homologs may require some luck. Key questions include:
(1) Can one of the two chloride ligands of 7 be selectively substituted using any of the
X(CC) X' building blocks employed above? (2) If not, can a mixture of mono- and
2
disubstitution products be easily separated? If yes, it should be possible to access a
-15-

Dalton Transactions
Page 16 of 45
View Article Online
DOI: 10.1039/C9DT00870E
Pt(CC) H species that could undergo oxidative homocoupling to an octaplatinum
2
complex. Another approach would involve converting both termini of triplatinum complex
29
10 to Pt(CC) H moieties. A subsequent oxidative cross coupling with excess 2 –
2
analogous to the reaction of 8 and excess 2 used to access 10 – would afford a penta-
platinum complex.
We are also interested in altering the dimensionality in which the polyynediyl
segments in the title complexes are arrayed. In a complementary investigation, we have
described efficient routes to adducts in which two Pt(CC) Pt moieties (n = 3, 4) bear
n
lateral (as opposed to longitudinal) relationships, as illustrated by 21 in Scheme 6
9g
(middle). These may be regarded as precursors to multistranded molecular wires. A
priori, there is no impediment to extending the synthetic methodology (treatment of
triarylphosphine precursors with the 1,3-diphosphine Ph P(CH ) PPh ) to 3, 10, and 7.
2
2 3
2
Another approach to altering the dimensionality of the title complexes would
involve reactions with 1,2-diphosphines. For example, we find that triarylphosphine
ligands in diplatinum polyynediyl complexes trans,trans-Ar'(Ar P) Pt(CC) Pt(PAr ) Ar'
3
2
4
3 2
9g
can be replaced by Ph PCH CH PPh
2
and presumably tetraalkyl analogs
2
2
2
31
Me PCH CH PMe . This results in a cis,cis isomer. As shown in the hypothetical
2
2
2
2
reaction in Scheme 6 (bottom), analogous substitutions would delinearize or "kink" the -
L PtCCCCCCCC- repeat units, transforming them to two (or three) dimensional
2
structures that have tantalizing possibilities as precursors to molecular polygons and
related species.
2. Analyses of properties. As summarized in Table 3, the thermal stabilities of the
title dichloride and bis(thioacetate) complexes are striking. They all persist to >160 °C in
the solid state. In most cases, exotherms are detected, but for 3, 10, and 7, mass loss
begins only at much higher temperatures. Solutions of 3, 10, 7, and the thioacetate
analogs showed no deterioration after several hours in air. These data auger well for the
isolation of higher homologs.
-16-

Page 17 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
31
As shown in Table 1, the P NMR signals of the phosphine ligands on the
internal platinum atoms (CPt(Pp-tol ) )C) are 2.7-3.4 ppm upfield of those on the
3 2
13
terminal platinum atoms ( 16.7-16.8 vs. 19.4-20.1 ppm). In contrast, the C NMR
signals of the sp carbon atoms on the internal platinum atoms (CPtC) are downfield
(105.8-106.1 ppm for 10, 7, and the SAc analogs) from those on the terminal platinum
atoms (XPtC; X = Cl, 83.7 ppm; X = SAc, 95.3 ppm). The same trend is found for the
corresponding PtCC carbon atoms (X = Cl, 95.9 vs. 88.5-88.6 ppm; X = SAc, 95.9 vs.
92.9-93.0 ppm). As noted for many other octatetraynediyl complexes, the chemical
shifts of the four innermost sp carbon atoms fall into a relatively narrow range (58.7-63.6
8,9
ppm).
NICS calculations that may aid additional assignments have recently been
32
reported.
As summarized in Table 1, the IR 
patterns are practically identical for the
CC
title dichloride and bis(thioacetate) complexes, regardless of number of -
–1
–1
L PtCCCCCCCC- repeat units (2138-2142 cm m, 1999-2008 cm w vs. 2142-
2
–1
–1
2150 cm m, 1999-2011 cm w). In contrast, the UV-visible spectra (Figure 2 and
Table 4) show progressively more intense and red-shifted absorptions with increased
chain length. Accordingly, the tetraplatinum complexes (7, 15) are orange, but the
others are yellow. The homology between the spectra of 7 and 15, as well as the
triplatinum complexes 10 and 14 (Figure 2), is striking. These trends indicate substantial
electronic interactions between the tetrayne moieties, which in a separate study has
14
been principally ascribed to dπ(Pt)-pπ(C) overlap. This overlap furthermore plays a
14
role in the excited state photophysics of 10 and 7. It is also apparent that longer
wavelength absorptions intensify and red-shift when chloride ligands are replaced by
(CC) SiMe or (CC) H ligands (Figure 2).
2
3
2
As noted in the results section, there are no exceptional bond lengths or angles
in the crystal structures in Figures 3 and 4. However, the structures do convey a visual
impression that anchoring a -S-Pt linkage to a gold break junction, STM tip, or the like
-17-

Dalton Transactions
Page 18 of 45
View Article Online
DOI: 10.1039/C9DT00870E
has the potential to be sterically impeded by cis-Pp-tol ligands. The Au-S distances on
3
33
…
gold surfaces have been calculated to be 2.36 Å, which translates to Au Pt distances
of about 4.7 Å for any -S-Pt species derived from our complexes. Although crystal
structures could not be obtained for the analogous trimethylphosphine complexes 4 or
16, one can mentally strip away all but the ipso carbon atoms from the phosphine
ligands in Figures 3 and 4. It is clear that in such less congested environments, such as
would be experienced with Me P ligands (4, 16), the -S-Pt moiety could more readily
3
anchor to any tip or surface. Several platinum alkynyl complexes have been subjected
to single molecule measurements, but most of these have featured ligand based thiol
24
groups. A well characterized silver nanoparticle based assembly that exploits -S-Pt
23
linkages, trans,trans-Ag-S-L Pt-CC-biphenylene-CC-PtL -S-Ag, has been reported.
2
2
Here n-Bu P ligands (L) that are cis to the -S-Pt linkage could be successfully
3
employed.
3. Conclusion. This study has provided the first series of longitudinally extended
linear polymetallic/sp carbon arrays to be obtained by directed synthesis, as opposed to
polymerization or oligomerization. The general methodology can likely be applied to still
higher homologs as noted above. The net result is a well defined series of stable, easily
handled, functionalizable building blocks that may be of use for molecular devices or
new synthetic directions (Scheme 6), and aid in understanding the transition between
the molecular and macromolecular limit for polymers that feature metals in the main
chain. Strategies for optimizing the anchoring of such complexes via metal-sulfur
linkages to noble metal surfaces or STM tips have also been suggested.
-18-

Page 19 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
Experimental Section
General. Reactions were conducted under dry N atmospheres using standard
2
Schlenk techniques. Workups of platinum complexes were carried out in air. Solvents
were treated as follows: THF, Et O, and hexane, distilled from Na/benzophenone;
2
acetone, distilled from CaCl , CH Cl , distilled from K CO ; MeOH, distilled from Mg.
2
2
2
2
3
The following were used as received: n-BuLi (1.6 M in hexane, Acros), TMEDA (99%,
Janssen), CuCl and CuI (2  Aldrich, 99.99%, and other sources), HNEt (common
2
+
–
commercial sources), n-Bu N F (1.0 M in THF, 5 wt% H O, Aldrich), ClSnMe (99%,
4
2
3
Acros), ClSiMe (Lancaster), potassium thioacetate (KSAc; Lancaster), Me P (1.0 M in
3
3
toluene, Aldrich), and alumina for chromatography (neutral, Fluka).
NMR spectra were obtained on standard 300 or 400 MHz spectrometers. IR and
mass spectra were recorded on ASI React-IR 1000 and Micromass Zabspec
instruments, respectively. DSC and TGA data were obtained with a Mettler-Toledo
34
9b
DSC-821 instrument. Cyclic voltammograms were recorded as described earlier
and in Table 7. Microanalyses were conducted on a Carlo Erba EA1110 instrument.
trans-Cl(p-tol P) Pt(CC) SiMe (1). A round bottom flask was charged with cis
3
2
2
3
16
or trans-(p-tol P) PtCl (0.874 g, 1.00 mmol), Me Sn(CC) SiMe (0.285 g, 1.00
3
2
2
3
2
3
mmol), and THF (120 mL), and fitted with a condenser. The solution was refluxed (24
h). The solvent was removed by rotary evaporation and the residue chromatographed
on an alumina column (2.5  30 cm, 1:3 v/v CH Cl /hexane). The solvent was removed
2
2
from the product containing fraction (R (TLC) 0.23) by rotary evaporation to give 1 as a
f
pale yellow solid (0.600 g, 0.625 mmol, 63%), dec pt 238 °C (capillary). Calcd for
C H ClP PtSi: C, 61.27; H, 5.35. Found: C, 61.14; H, 5.30.
49 51
2
1
3
NMR (, CDCl ): H 7.59-7.54 (m, 12H, o to P), 7.17 (d, J = 7.8 Hz, 12 H, m to
3
HH
13
1
P), 2.36 (s, 18H, CCH ), 0.02 (s, 9H, SiCH ); C{ H} 140.5 (s, p to P), 134.9 (virtual t,
3
3
2
35
3
35
1
J
= 6.0 Hz, o to P), 128.7 (virtual t, J = 5.6 Hz, m to P), 126.6 (virtual t, J
CP CP
CP
35
2
= 30.5 Hz, i to P), 92.7, 87.9 (2t, J = 2.3, 3.2 Hz, PtCCC), 84.0 (t, J = 14.8 Hz,
CP
CP
-19-

Dalton Transactions
Page 20 of 45
View Article Online
DOI: 10.1039/C9DT00870E
31
1
1
PtC), 77.6, (s, CSi), 21.6 (s, CCH ), 0.4 (s, SiCH ); P{ H} 20.1 (s, J
= 2564
3
3
PPt
36
37
+
+
Hz). IR: Table 1. UV-vis: Table 4. MS 960 (9%, 1 ), 924 (18%, 1–Cl ), 851 (19%,
+
+
1–Cl–SiMe  ), 803 (100%, [(tol P) Pt] ).
3
3
2
trans-Cl(p-tol P) Pt(CC) H (2). A round bottom flask was charged with 1 (0.500
3
2
2
+
–
g, 0.521 mmol), THF (20 mL), and n-Bu N F (1.0 M in THF/5 wt% H O; 0.200 mL,
4
2
0.200 mmol). The solution was stirred (0.5 h). Then H O (60 mL) was added. The
2
mixture was extracted with CH Cl (3  80 mL), and the solvent removed by rotary
2
2
evaporation. The residue was dissolved in THF (2 mL), and MeOH (20 mL) added. The
precipitate was collected by filtration and dried by oil pump vacuum to give 2 as a
slightly yellow solid (0.443 g, 0.499 mmol, 96%), dec pt 110 °C (capillary). Calcd for
C H ClP Pt: C, 62.20; H, 4.88. Found: C, 62.18; H, 4.86.
46 43
2
1
3
NMR (, CDCl ): H 7.58-7.53 (m, 12H, o to P), 7.17 (d, J
= 7.8 Hz, 12 H, m
HH
3
13
1
to P), 2.35 (s, 18H, CH ), 1.42 (s, 1H, CH); C{ H} 140.6 (s, p to P), 134.9 (virtual t,
3
2
35
3
35
1
J
= 6.3 Hz, o to P), 128.7 (virtual t, J = 5.6 Hz, m to P), 126.5 (virtual t, J
CP CP
CP
35
3
2
= 30.3 Hz, i to P), 86.8 (t, J = 2.8 Hz, PtCC), 80.5 (t, J = 14.3 Hz, PtC), 67.9
CP
CP
1
4
31
1
(t, J = 2.3 Hz, PtCCC), 59.8 (s, CH), 21.6 (s, CH ); P{ H} 20.2 (s, J
= 2560
CP
36
3
PPt
37
+
+
Hz). IR: Table 1. UV-vis: Table 4. MS 888 (9%, 2 ), 852 (22%, 2–Cl ), 802
+
(100%, [(tol P) Pt] ).
3
2
trans,trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) Cl (3). A three neck flask was
3
2
4
3 2
charged with 2 (0.300 g, 0.338 mmol) and acetone (23 mL), and fitted with a gas
dispersion tube and a condenser. The solution was heated to 30 °C. A Schlenk flask
was charged with CuCl (0.230 g, 2.32 mmol) and acetone (23 mL), and TMEDA (0.460
mL, 3.07 mmol) was added with stirring. After 0.5 h, stirring was halted, and a grayish
solid separated from a blue supernatant. Then O was bubbled through the three neck
2
flask with stirring. After ca. 5 min, the blue supernatant was added in portions. After 4 h,
the solvent was removed by rotary evaporation. The residue was chromatographed on a
silica gel column (2.5  40 cm, 67:33 v/v CH Cl /hexane). The solvent was removed
2
2
-20-

Page 21 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
from the product containing fraction (R (TLC) 0.48) by rotary evaporation and oil pump
f
vacuum to give 3 as a yellow solid (0.205 g, 0.116 mmol, 68%). The sample slightly
darkened at 170 °C, slowly turned black with further heating, and liquefied at 299 °C
(capillary). DSC/TGA: Table 3. Calcd for C H Cl P Pt : C, 62.27; H, 4.77. Found: C,
92 84 2 4
2
62.01; H, 5.08.
NMR (, CDCl ): H 7.56-7.51 (m, 24H, o to P), 7.15 (d, J
1
3
= 7.8 Hz, 24H, m
HH
3
13
1
2
35
to P), 2.34 (s, 36H, CH ); C{ H} 140.7 (s, p to P), 134.8 (virtual t, J = 6.1 Hz,
o
3
CP
3
35
1
35
to P), 128.4 (virtual t, J = 5.4 Hz, m to P), 126.4 (virtual t, J = 29.8 Hz, i to P),
CP
2
CP
88.5 (s, PtCC), 83.6 (t, J = 15.3 Hz, PtC), 63.4 (s, PtCCC), 58.9 (s, PtCCCC),
CP
31
1
1
36
37
21.5 (s, CH ); P{ H} 20.1 (s, J
= 2553 Hz). IR: Table 1. UV-vis: Table 4. MS
PPt
3
+
+
+
+
1773 ([3] , 6%), 802 ([(tol P) Pt] , 100%), 497 ([tol PPt] , 50%), 405 ([tol PPt] , 92%).
3
2
3
2
trans,trans-Cl(Me P) Pt(CC) Pt(PMe ) Cl (4). A Schlenk flask was charged
3
2
4
3 2
with 3 (0.186 g, 0.105 mmol, 1.0 equiv) and CH Cl (12 mL). Then Me P (1.0 M in
2
2
3
toluene; 0.50 mL, 0.50 mmol, 4.8 equiv) was added via syringe. The mixture was stirred
until alumina TLC (30/70 v/v CH Cl /hexane) showed 3 to be consumed (1 h). The
2
2
solvents were removed by oil pump vacuum and the residue was filtered through a silica
gel column (2  5 cm, 85:15 v/v CH Cl / MeOH). The solvent was removed from the
2
2
filtrate by rotary evaporation. The residue was dissolved in CH Cl , and hexane was
2
2
added. The precipitate was collected by filtration and dried by oil pump vacuum to give
4 as a yellow solid (0.078 g, 0.090 mmol, 86%). The sample turned black at 220 °C and
remained solid at 330 °C (capillary). Calcd for C H Cl P Pt : C, 27.88; H, 4.21.
20 36 2 4
2
Found: C, 27.41; H, 4.20.
1
2
35 3
35
NMR (, CDCl3): H 1.57 (virtual t, J
= 3.5 Hz,
J
= 25.6 Hz, 36H,
HPt
HP
13
1
2
CH ); C{ H} 84.7 (s, PtCC), 80.4 (t, J
= 17.0 Hz, PtC), 63.5 (s, PtCCC), 57.6
CP
3
1
35 3
35
31
1
(s, PtCCCC), 13.5 (virtual t, J
= 19.4 Hz,
J
= 76.3 Hz, CH ); P{ H}
CP
HPt
3
1
36
37
+
+
13.4 (s, J
= 2284 Hz). IR: Table 1. MS: 861 ([4] , 100%), 825 ([4Cl] , 30%),
PPt
+
749 ([4ClMe P] , 60%).
3
-21-

Dalton Transactions
Page 22 of 45
View Article Online
DOI: 10.1039/C9DT00870E
trans,trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) (CC) SiMe (5). A round bottom
3
2
4
3 2
2
3
flask was charged with 3 (0.235 g, 0.124 mmol) and CHCl (2.5 mL). A solution of
3
Me Sn(CC) SiMe (0.038 g, 0.13 mmol) in CHCl (2.5 mL) was slowly added by
3
2
3
3
syringe over 4 h with stirring. After another 18 h, the solvent was removed by rotary
evaporation. The residue was chromatographed on an alumina column (1  40 cm, 2:3
v/v CH Cl /hexane). The solvent was removed from the product containing fraction (R
f
2
2
(TLC) 0.60) by rotary evaporation and oil pump vacuum to give 5 as a yellow solid
(0.112 g, 0.060 mmol, 46%). The sample slightly darkened at 245 °C, slowly turned
black with further heating, and liquefied at 289 °C (capillary). Calcd for
C H ClP Pt Si: C, 63.92; H, 5.04. Found: C, 63.48; H, 5.03.
99 93
4
2
1
3
NMR (, CDCl ): H 7.57-7.48 (m, 24H, o to P), 7.14 (d, J
= 7.7 Hz, 24H, m
HH
3
13
1
to P), 2.34, 2.33 (2s, 36H, CCH ), 0.00 (s, 9H, SiCH ); C{ H} 140.7, 140.5 (2s, p to
3
3
2
35
3
P), 134.9, 134.8 (2 virtual t, J = 4.6, 5.1 Hz, o to P), 128.7, 128.6 (2 virtual t, J
CP
CP
35
1
35
= 5.6, 5.6 Hz, m to P), 127.4, 126.5 (2 virtual t, J = 30.5, 30.5 Hz, i to P), 106.1,
CP
1
2
105.7 (2t, J = 12.8, 14.8 Hz, CPtCCCCSiMe ) 83.6 (t, J = 14.9 Hz, ClPtC),
CP
3
CP
95.9,
Me SiCCCCPtCCCCCCC), 21.5 (s, CCH ), 0.3 (s, SiCH ); P{ H} 20.1 (s, J
PPt
95.1,
92.4,
88.6,
68.0,
63.6,
63.3,
59.0,
58.7
(9s,
31
1
1
3
3
3
36
1
36
37
= 2556 Hz), 16.8 (s, J
= 2523 Hz). IR: Table 1. UV-vis: Table 4. MS 1857
PPt
+
+
+
([5] , 13%), 924 ([(tol P) PtC SiMe ] , 9%) (802 ([(tol P) Pt] , 100%).
3
2
4
3
3
2
trans,trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) (CC) H (6). A round bottom flask
3
2
4
3 2
2
+
–
was charged with 5 (0.200 g, 0.108 mmol), CHCl (5 mL), and n-Bu N F (1.0 M in
3
4
THF/5 wt% H O; 0.100 mL, 0.100 mmol). The solution was stirred (24 h). The solvent
2
was removed by oil pump vacuum. The residue was chromatographed on a silica gel
column (3  30 cm, 1:1 v/v CH Cl /hexane). The solvent was removed from the product
2
2
containing fraction by rotary evaporation and oil pump vacuum to give 6 as an orange
solid (0.097 g, 0.054 mmol, 50%).
1
3
NMR (, CDCl ): H 7.54-7.49 (m, 24H, o to P), 7.15 (d, J
= 7.3 Hz, 24H, m
HH
3
-22-

Page 23 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
13
1
to P), 2.35, 2.33 (2s, 36H, CH ), 1.45 (s, 1H, CH); C{ H} 140.7, 140.6 (2s, p to P),
3
2
35
3
134.9, 134.8 (2 virtual t, J
= 6.1, 6.1 Hz, o to P), 128.7, 128.6 (2 virtual t, J
=
CP
CP
35
1
35
4.6, 6.1 Hz, m to P), 127.4, 126.5 (2 virtual t, J
= 30.5, 29.3 Hz, i to P), 106.0,
CP
2
2
102.6 (2t, J
= 15.2, 15.2 Hz, CPtCCCCH), 83.7 (t, J
= 13.7 Hz, ClPtC),
CP
CP
95.7, 93.9, 88.5, 72.0, 63.6, 63.2, 59.8, 59.0 58.8 (9s, HCCCCPtCCCCCCC),
31
1
1
36
1
36
21.5 (s, CH ); P{ H} 20.1 (s, J
= 2553 Hz), 16.7 (s, J
= 2534 Hz). IR:
PPt
3
PPt
37
+
+
+
Table 1. MS 1787 ([6] , 13%), 1752 ([6] Cl, 5%), 802 ([(tol P) Pt] , 100%).
3
2
trans,trans,trans,trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) (CC) (p-tol P) Pt-
3
2
4
3 2
4
3
2
(CC) Pt(Pp-tol ) Cl (7). A. A three neck flask was charged with 6 (0.120 g, 0.0670
4
3 2
mmol) and acetone (20 mL), and fitted with a gas dispersion tube and a condenser. A
Schlenk flask was charged with CuCl (0.200 g, 2.02 mmol) and acetone (5 mL), and
TMEDA (0.200 mL, 1.33 mmol) was added with stirring. After 0.5 h, stirring was halted,
and a grayish solid separated from a blue supernatant. Then O was bubbled through
2
the three neck flask with stirring. After ca. 5 min, the blue supernatant was added in
portions. After 6 h, the solvent was removed by rotary evaporation. The residue was
chromatographed on a silica gel column (3  15 cm, 1:1 v/v CH Cl /hexane). The
2
2
solvent was removed from the product containing fraction (R (TLC) 0.12) by rotary
f
evaporation and oil pump vacuum to give 7 as an orange solid (0.048 g, 0.013 mmol,
48%). B. A three neck flask was charged with 5 (0.200 g, 0.108 mmol) and THF (10
+
–
mL), and fitted with a gas dispersion tube and a condenser. Then n-Bu N F (1.0 M in
4
THF/5 wt% H O; 0.100 mL, 0.100 mmol) was added with stirring. After 24 h, Me SiCl
2
3
(0.050 mL, 0.40 mmol) was added. After 10 min, acetone (25 mL) was added and the
solution was heated to 30 °C. A Schlenk flask was charged with CuCl (0.318 g, 3.21
mmol) and acetone (20 mL), and TMEDA (0.500 mL, 3.33 mmol) was added with
stirring. After 0.5 h, stirring was halted, and a greyish solid separated from a blue
supernatant. Then O was bubbled through the three necked flask with stirring. After ca.
2
5 min, the blue supernatant was added in portions. After 4 h, the solvent was removed
-23-

Dalton Transactions
Page 24 of 45
View Article Online
DOI: 10.1039/C9DT00870E
by rotary evaporation. The residue was chromatographed on a silica gel column (3  25
cm, 1:1 v/v CH Cl /hexane). The solvent was removed from the product containing
2
2
fraction (R (TLC) 0.11) by rotary evaporation and oil pump vacuum to give 7 as an
f
orange solid (0.151 g, 0.0422 mmol, 79%). The samples slightly darkened at 235 °C
and became black at 288 °C (capillary). DSC/TGA: Table 3. Calcd for
C
H
Cl P Pt : C, 64.52; H, 4.74. Found: C, 64.48; H, 5.00.
192 168 2 8 4
1
NMR (, CDCl ): H 7.54-7.45 (m, 48H, o to P), 7.14-7.10 (m, 48H, m to P), 2.33,
3
13
1
2.32 (2s, 36H, CH ); C{ H} (100 MHz, CDCl ): 140.7 (s, p to P), 134.8, 134.7 (2
3
3
2
35
35 3
virtual t, J = 6.0, 6.0 Hz, o to P), 128.6, 128.7 (2 virtual t,
J
= 5.1, 5.1 Hz , m
CP
CP
35 1
2
to P), 127.2, 126.5 (2 virtual t,
J
= 30.5, 30.5 Hz, i to P), 106.1, 105.8 (2t, J
=
CP
CP
38
2
16.0, 16.0 Hz, CPtC), 95.9 (CCPtCC), 88.6 (ClPtCC), 83.7 (t, J
= 9.6 Hz,
CP
ClPtC),
63.6,
63.4,
63.2,
59.0
(2

intensity),
58.6
(5s,
31
1
1
36
ClPtCCCCCCCCPtCCCC), 21.4 (s, CH ); P{ H} 20.1 (s, J
= 2553 Hz),
PPt
3
1
36
37
+
16.7 (s, J
= 2520 Hz). IR: Table 1. UV-vis: Table 4. MS 3574 ([7] , <1%), 802
PPt
+
([(tol P) Pt] , 100%).
3
2
trans-H(CC) Pt(Pp-tol ) (CC) H (8). A. A Schlenk flask was charged with cis-
2
3 2
2
16
or trans-(p-tol P) PtCl (0.875 g, 1.00 mmol), CuI (0.060 g, 0.30 mmol), and HNEt
2
3
2
2
(75 mL). The mixture was cooled to –45 °C (CO /CH CN), and H(CC) H (1.43 M in
2
3
2
39
THF; 20 mL, 28.6 mmol) added with stirring. After 1 h, the cold bath was removed.
After another 1.75 h, the solvent was removed by oil pump vacuum. The residue was
extracted with toluene (3  10 mL). The extracts were filtered through an alumina
column (12 cm), which was rinsed with toluene until colorless. The toluene was
removed by rotary evaporation. The residue was reprecipitated from CH Cl /hexane,
2
2
collected by filtration, and dried by oil pump vacuum to give 8 as a pale yellow solid
(0.428 g, 0.475 mmol, 47%). B. A Schlenk flask was charged with 9 (0.875 g, 0.836
+
–
mmol), THF (20 mL), and n-Bu N F (1.0 M in THF/5 wt% H O; 0.200 mL, 0.200
4
2
mmol). The solution was stirred (0.5 h). The solvent was removed by oil pump vacuum.
-24-

Page 25 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
The residue was chromatographed on a silica gel column (3  15 cm; 2:3 v/v
CH Cl /hexane). The solvent was removed from the product containing fraction by
2
2
rotary evaporation and oil pump vacuum to give 8 as a pale yellow solid (0.727 g, 0.806
mmol, 96%). The samples slightly darkened at 170 °C, slowly turned black with further
heating, and remained solid at 350 °C (capillary). Calcd for C H P Pt: C, 66.58; H,
50 44 2
4.92. Found: C, 65.24; H, 4.93.
1
3
NMR (, CDCl ): H 7.58-7.53 (m, 12H, o to P), 7.17 (d, J
= 7.6 Hz, 12H, m
HH
3
13
1
to P), 2.36 (s, 18H, p to P)), 1.46 (s, 2H, CH); C{ H} 140.6 (s, p to P), 134.8 (virtual t,
2
35
3
35
1
J
= 6.5 Hz, o to P), 128.4 (virtual t, J = 6.1 Hz, m to P), 127.5 (virtual t, J
CP CP
CP
35
2
= 30.5 Hz, i to P), 102.7 (t, J = 15.3 Hz, PtCC), 93.8 (s, PtCC), 72.1 (s, CCH),
CP
31
1
1
36
37
59.7 (s, CH), 21.4 (s, CH ); P{ H} 17.0 (s, J
= 2527 Hz). IR: Table 1. MS
3
PPt
+
+
+
902 ([8] , 28%), 852 ([(tol P) PtC H] , 46%), 802 ([(tol P) Pt] , 100%).
3
2
4
3
2
trans-Me Si(CC) Pt(Pp-tol ) (CC) SiMe (9). A (Scheme 3). A Schlenk flask
3
2
3 2
2
3
16
was charged with cis- or trans-(p-tol P) PtCl (0.175 g, 0.200 mmol), CuI (0.020 g,
3
2
2
40
0.11 mmol), HNEt (15 mL), H(CC) SiMe (0.122 g, 0.998 mmol), and CH Cl (5
2
2
3
2
2
mL). The solution was stirred (2 h) and then refluxed (2 h). The solvent was removed by
rotary evaporation. The residue was extracted with toluene (3  50 mL) The extracts
were filtered through a alumina column (7 cm). The solvent was removed by rotary
evaporation. The residue was suspended in MeOH (10 mL). The solid was collected by
filtration and dried by oil pump vacuum to give 9 as a yellow solid (0.162 g, 0.155 mmol,
78%). B (Scheme 5). A Schlenk flask was charged with 3 (0.090 g, 0.051 mmol), CuI
40
(0.005 g, 0.03 mmol), HNEt (10 mL), and H(CC) SiMe (0.030 g, 0.25 mmol). The
2
2
3
mixture was stirred (23 h). The solvent was removed by oil pump vacuum. The residue
was extracted with toluene (3  25 mL), and a workup identical to that in A gave 9 as a
yellow solid (0.076 g, 0.039 mmol, 77%), dec pt 259 °C (capillary). Calcd for
C H P PtSi : C, 64.29; H, 5.78. Found: C, 63.98; H, 5.81.
56 60 2
2
1
3
NMR (, CDCl ): H 7.56-7.51 (m, 12H, o to P), 7.16 (d, J
= 7.8 Hz, 12H, m
HH
3
-25-

Dalton Transactions
Page 26 of 45
View Article Online
DOI: 10.1039/C9DT00870E
13
1
to P), 2.36 (s, 18H, CCH ), 0.00 (s, 18H, SiCH ); C{ H} 140.3 (s, p to P), 134.7
3
3
2
35
3
35
(virtual t, J
= 6.5 Hz, o to P), 128.5 (virtual t, J
= 5.5 Hz, m to P), 127.4
CP
CP
CP
1
35
2
(virtual t, J
= 30.3 Hz, i to P), 105.9 (t, J
= 14.7 Hz, PtCC), 95.2, 92.6 (2s,
CP
31
1
1
PtCCC), 77.2 (s, CSi), 21.6 (s, CCH ), 0.4 (s, SiCH ); P{ H} 16.8 (s, J = 2540
PPt
3
3
36
37
+
+
Hz). IR: Table 1. UV-vis: Table 4. MS 1046 ([9] , 20%), 924 ([(tol P) PtC SiMe ] ,
3
2
4
3
+
24%), 802 ([(tol P) Pt] , 100%).
3
2
trans,trans,trans-Cl(p-tol P) Pt(CC) Pt(Pp-tol ) (CC) Pt(Pp-tol ) Cl (10). A
3
2
4
3 2
4
3 2
+
three neck flask was charged with 1 (0.500 g, 0.521 mmol), THF (20 mL), and n-Bu N
4
–
F (1.0 M in THF/5 wt% H O; 0.200 mL, 0.200 mmol). The solution was stirred (0.5 h).
2
–1
An IR spectrum showed complete conversion to 2 (2154 cm ), and Me SiCl (0.050 mL,
3
0.40 mmol) was added. After 10 min, acetone (40 mL) and 8 (0.118 g, 0.131 mmol)
were added. A Schlenk flask was charged with CuCl (0.500 g, 5.05 mmol) and acetone
(20 mL), and TMEDA (1.00 mL, 6.65 mmol) was added with stirring. After 0.5 h, stirring
was halted, and a greyish solid separated from a blue supernatant. Then O was
2
bubbled through the three neck flask with stirring. After ca. 5 min, the blue supernatant
was added in portions. After 6 h, the solvent was removed by rotary evaporation. The
residue was chromatographed on a silica gel column (3  30 cm, 2:1 v/v
CH Cl /hexane). The combined product fractions were taken to dryness and again
2
2
chromatographed on a silica gel column (3  65 cm, 1:1 v/v CH Cl /hexane). The
2
2
solvent was removed from the product containing fractions (R (THF) 0.14 for 3, 0.12 for
f
10) by rotary evaporation and oil pump vacuum to give 3 as a yellow solid (0.154 g,
0.0868 mmol, 33% based upon 1) and 10 as an orange solid (0.127 g, 0.0475 mmol,
36% based upon 8). The sample of 10 slightly darkened at 278 °C, turned black at 288
°C, and liquefied at 308 °C (capillary). DSC/TGA: Table 3. Calcd for C
H
Cl P Pt :
142 126 2 6 3
C, 63.77; H, 4.75. Found: C, 63.67; H, 4.88.
1
NMR (, CDCl ): H 7.55-7.46 (m, 36 H, o to P), 7.16-7.12 (m, 36 H, m to P),
3
13
1
2
2.34 (s, 54 H, CH ); C{ H} 140.7 (s, p to P), 134.8, 134.7 (2 virtual t, J = 6.1, 6.1
3
CP
-26-

Page 27 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
35
3
35
1
Hz, o to P), 128.7 (virtual t, J = 5.4 Hz, m to P), 127.2, 126.4 (2 virtual t, J
=
CP
CP
35
2
30.5, 30.5 Hz, i to P), 105.8 (t, J = 15.3 Hz, CPtC), 95.9 (s, CCPtCC), 88.5 (s,
CP
2
ClPtCC), 83.7 (t,
J
= 14.5 Hz, ClPtC), 63.6, 63.2, 58.94, 58.86 (4s,
CP
31
1
1
36
PtCCCCCCCCPt), 21.4 (s, CH ); P{ H} 20.1 (s, J
= 2556 Hz), 16.7 (s,
3
PPt
1
36
37
+
J
= 2520 Hz). IR: Table 1. UV-vis: Table 4. MS 2675 ([10] , 5%), 802 ([(tol P) -
PPt
+
3
2
Pt] , 100%).
trans,trans-Me Si(CC) (p-tol P) Pt(CC) Pt(Pp-tol ) (CC) SiMe
(17).
round bottom flask was charged with 3 (0.220 g, 0.124 mmol), Me Sn(CC) SiMe
3
A
3
2
3
2
4
3 2
2
3
3
2
(0.075 g, 0.26 mmol), and CHCl (2.5 mL). The solution was stirred (4 h). The solvent
3
was removed by rotary evaporation. The residue was chromatographed on an alumina
column (3.5  20 cm, 2:3 v/v CH Cl /hexane). The solvent was removed from the
2
2
product containing fractions (R (TLC) 0.77) by rotary evaporation and oil pump vacuum
f
to give 17 as a yellow solid (0.186 g, 0.0956 mmol, 77%). The sample slightly darkened
at 210 °C, slowly turned black with further heating, and remained solid at 330 °C
(capillary). DSC: Table 3. Calcd for C
H
P Pt Si : C, 65.42; H, 5.28. Found: C,
106 102 4 2 2
65.39; H, 5.19.
1
3
NMR (): H (CDCl ) 7.52-7.47 (m, 24H, o to P), 7.13 (d, J
= 7.9 Hz, 24H, m
HH
3
13
1
to P), 2.34 (s, 36H, CCH ), 1.45 (s, 18H, SiCH ); C{ H} (CD Cl ) 141.5 (s, p to P),
3
3
2
2
2
35
3
35
135.0 (virtual t, J
= 12.0 Hz, o to P), 128.6 (virtual t, J
= 12.1 Hz, m to P),
CP
CP
1
35
2
127.4 (virtual t, J
= 61.0 Hz, i to P), 107.1, 105.9 (2t, J
= 15.3, 14.8 Hz,
CP
CP
CPtC), 95.59, 95.57, 92.6, 77.7, 63.6, 58.8 (6s, SiCCCCPtCCCC), 21.6 (s,
31
1
1
36
CCH ), 0.3 (s, SiCH ); P{ H} (CDCl ) 16.6 (s, J
= 2534 Hz). IR: Table 1. UV-
3
3
3
PPt
37
+
+
vis: Table 4. MS
1945 ([17] , 8%), 924 ([(tol P) PtC SiMe ] , 24%), (803
3
2
4
3
+
([(tol P) Pt] , 100%).
3
2
trans,trans-H(CC) (p-tol P) Pt(CC) Pt(Pp-tol ) (CC) H (18). A round bottom
2
3
2
4
3 2
4
+
–
flask was charged with 17 (0.285 g, 0.146 mmol) and THF (30 mL). Then n-Bu N F
4
(1.0 M in THF/5 wt% H O; 0.400 mL, 0.400 mmol) was added with stirring. After 0.5 h,
2
-27-

Dalton Transactions
Page 28 of 45
View Article Online
DOI: 10.1039/C9DT00870E
the solvent was removed by oil pump vacuum. The residue was chromatographed on a
silica gel column (3  15 cm, 40:60 v/v CH Cl /hexane). The solvent was removed from
2
2
the product containing fractions by rotary evaporation and oil pump vacuum to give 18
as an orange solid (0.252 g, 0.140 mmol, 96%), dec pt 175 °C (capillary). DSC/TGA:
Table 3. Calcd for C H P Pt : C, 66.66; H, 4.81. Found: C, 67.03; H, 5.38.
100 86 4
1
2
3
NMR (, CDCl ): H 7.54-7.49 (m, 24H, o to P), 7.15 (d, J
= 7.8 Hz, 24H, m
HH
3
13
1
to P), 2.34 (s, 36H, CH ), 1.45 (s, 2H, CH); C{ H} 140.6 (s, p to P), 134.7 (virtual t,
3
2
35
3
35
J
J
= 12.3 Hz, o to P), 128.6 (virtual t, J
= 10.7 Hz, m to P), 127.3 (virtual t,
CP
CP
CP
1
35
2
= 61.0 Hz, i to P), 106.0, 102.6 (2t, J
= 15.3, 15.3 Hz, CPtC), 95.7, 93.9,
CP
31
1
1
72.0, 63.4, 59.8, 58.9 (6s, HCCCCPtCCCC), 21.4 (s, CH ); P{ H} 16.7 (s, J
3
PPt
36
37
+
= 2529 Hz).
IR: Table 1. UV-vis: Table 4. MS
1800 ([18] , 13%), 852
+
+
([(tol P) PtC H] , 15%), (803 ([(tol) P) Pt] , 100%).
3
2
4
3
2
trans-(p-tol)(p-tol P) Pt(SAc) (12). A Schlenk flask was charged with trans-(p-
3
2
9b
tol)(p-tol P) PtCl (11; 0.186 g, 0.200 mmol), KSAc (0.036 g, 0.32 mmol), and CH Cl
2
3
2
2
(10 mL). The mixture was stirred (20 h). The solvent was removed by oil pump vacuum.
The residue was chromatographed on a silica gel column (2  10 cm, CH Cl ). The
2
2
solvent was removed from the product containing fraction (TLC) by rotary evaporation
and oil pump vacuum to give 12 as a white solid (0.145 g, 0.149 mmol, 75%). The
sample slightly darkened at 208 °C, slowly turned black with further heating, and
liquefied at 238 °C (Capillary). DSC: no endotherm or exotherm below 230 °C. TGA:
onset of mass loss, 224 °C. Calcd for C H OP PtS: C, 63.15; H, 5.40; S, 3.31.
51 52
2
Found: C, 62.78; H, 5.64; S, 3.66.
1
3
NMR (, CDCl ): H 7.41-7.36 (m, 12H, o to P), 7.03 (d, J = 7.7 Hz, 12H, m to
3
HH
3
3
P), 6.40 (d, J = 7.9 Hz, 2H, o to Pt), 5.95 (d, J = 7.7 Hz, 2H, m to Pt), 2.30 (s,
HH
HH
13
1
18H, PC H CH ), 1.88 (s, 3H, PtC H CH ), 1.48 (s, 3H, C(O)CH ); C{ H} 204.3 (s,
6 4
3
2
6 4
3
3
C=O), 141.7 (t, J = 9.2 Hz, i to Pt), 139.3 (s, p to P), 137.6 (s, o to Pt), 134.6 (virtual
CP
35
2
2
35
t, J = 6.0 Hz, o to P), 129.0 (s, p to Pt), 128.1 (virtual t, J = 5.1 Hz, m to P),
CP
CP
-28-

Page 29 of 45
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT00870E
1
35
127.9 (s, m to Pt), 127.5 (virtual t, J = 14.7 Hz, i to P), 34.3 (s, C(O)CH ), 21.4 (s,
CP
3
31
1
1
36
PC H CH , p to P), 20.5 (s, PtC H CH , p to Pt); P{ H} 21.1 (s, J = 3080 Hz).
PPt
6 4
3
6 4
3
1
37
+
IR (cm , powder film) 1613 (m, 
), 946 (m,  ). MS 969 ([12] , 1%), 894
C=O
C-S
+
+
+
([(tol P) (tol)Pt] , 45%), 803 ([(tol P) Pt] , 100%), 497 ([tol PPt] , 20%), 405
3
2
3
2
3
+
([tol PPt] , 25%).
2
trans,trans-(AcS)(p-tol P) Pt(CC) Pt(Pp-tol ) (SAc) (13). A Schlenk flask was
3
2
4
3 2
charged with 3 (0.177 g, 0.100 mmol), KSAc (0.034 g, 0.30 mmol), and CH Cl (10 mL).
2
2
The mixture was stirred (20 h). The resulting suspension was filtered through an
alumina column (2  3 cm), which was washed with CH Cl (15 mL). The solvent was
2
2
removed from the combined filtrate by rotary evaporation. Then CH Cl (5 mL) was
2
2
added, followed by hexane to precipitate the product. This procedure was repeated two
times. The precipitate was collected by filtration and dried by oil pump vacuum to give
13 as a yellow solid (0.168 g, 0.0906 mmol, 91%). The sample slightly darkened at 258
°C, slowly turned black with further heating, and liquefied at 293 °C (capillary).
DSC/TGA: Table 3. Calcd for C H O P Pt S : C, 62.19; H, 4.89; S, 3.46. Found: C,
96 90 2 4 2 2
62.36; H, 5.14; S, 3.17.
1
3
NMR (, CDCl ): H 7.53-7.48 (m, 24H, o to P), 7.12 (d, J = 7.8 Hz, 24H, m to
3
HH
13
1
P), 2.32 (s, 36H, C H CH ), 1.33 (s, 6H, C(O)CH ); C{ H} 203.0 (s, C=O), 140.3 (s, p
6 4
2
3
3
35
3
35
to P), 134.9 (virtual t, J = 6.0 Hz, o to P), 128.4 (virtual t, J = 5.5 Hz, m to P),
CP
CP
1
35
2
127.5 (virtual t, J = 30.3 Hz, i to P), 95.3 (t, J = 15.6, PtC), 93.0 (s, PtCC) ,
CP
CP
31
1
63.8, 59.4 (2s, PtCCCC), 33.3 (s, C(O)CH ), 21.5 (s, PC H CH , p to P); P{ H}
3
6 4
37
3
1
36
+
19.4 (s, J
= 2615 Hz). IR: Table 1. UV-vis: Table 4. MS 1853 ([13] , 5%), 1777
PPt
+
+
+
([13SAc] , 2%), 1549 ([13tol P] , 10%), 878 ([(AcS)(tol P) Pt] , 60%), 803
3
3
2
+
([(tol P) Pt] , 100%).
3
2
trans,trans,trans-(AcS)(p-tol P) Pt(CC) Pt(Pp-tol ) (CC) Pt(Pp-tol ) (SAc)
3
2
4
3 2
4
3 2
(14). Complex 10 (0.170 g, 0.064 mmol), KSAc (0.019 g, 0.17 mmol), and CH Cl (12
2
2
mL) were combined in a procedure analogous to that for 13. An identical workup gave
-29-