Short-chained platinum complex catalyzed hydrosilylation under thermomorphic conditions: Heterogeneous phase separation at ice temperature

Article abstract of DOI:10.3390/molecules26020378

Homogeneous catalysts PtCl₂ [5,5^′-bis-(n-ClCF₂ (CF₂ )₃ CH₂ OCH₂ )-2,2^′-bpy] (2A) and PtCl₂ [5,5^′-bis-(n-HCF₂ (CF₂ )₃ CH₂ OCH₂ )-2,2^′-bpy] (2B), which contained short fluorous chains, were synthe-sized and used in catalysis of hydrosilylation of alkynes. In these reactions the thermomorphic mode was effectively used to recover these catalysts from the reaction mixture up to eight cycles by taking advantage of heterogeneous phase separation at ice temperature. This kind of catalysis had previously been observed in fluorous catalysts of platinum containing about 50% F-content, but in this work the percentage of F-content is decreased to only about 30%, by which we termed them as “very light fluorous”. Our new type of catalyst with limited number of F-content is considered as the important discovery in the fluorous technology field as the reduced number of fluorine atoms will help to be able to comply the EPA 8-carbon rule. The metal leaching after the reaction has been examined by ICP-MS, and the testing results show the leaching of residual metal to be minimal. Additionally, comparing these results to our previous work, fluorous chain assisted selectivity has been observed when different fluorous chain lengths of the catalysts are used. It has been found that there exists fluorous chain assisted better selectivity towards β-(E) form in the Pt-catalyzed hydrosilylation of non-symmetric terminal alkyne when the Pt catalyst contains short fluorous chain (i.e., 4 Cs). Phenyl acetylenes showed the opposite regioselectivity due to pi-pi interaction while using the same catalyst via Markovnikov’s addition to form terminal vinyl silane, which is then a major product for Pt-catalyzed hydrosilylation of terminal aryl acetylene with triethylsilane. Finally, the kinetic studies indicate that the insertion of alkyne into the Pt-H bond is the rate-determining step.

Full text of DOI:10.3390/molecules26020378

molecules
Article
Short-Chained Platinum Complex Catalyzed Hydrosilylation
under Thermomorphic Conditions: Heterogeneous Phase
Separation at Ice Temperature
Chiao-Fan Chiu 1,2,†, Jinn-Hsuan Ho 3,†, Eskedar Tessema 4, Yijing Lu 4, Chia-Rui Shen 5,6, Chang-Wei Lin 7,
*
and Norman Lu 4,8,
*
1
2
3
4
5
6
7
8
Department of Pediatrics, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan;
chioufan2008@gmail.com
Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University,
Taoyuan 333, Taiwan
Department of Chemical Engineering, National Taiwan University of Technology, Taipei 106, Taiwan;
jhho@mail.ntust.edu.tw
Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 106, Taiwan;
eskedartessema18@gmail.com (E.T.); yijinglu@hotmail.com.tw (Y.L.)
Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University,
Taoyuan 333, Taiwan; crshen@mail.cgu.edu.tw
Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital,
Taoyuan 333, Taiwan
Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine,
Chang Gung Memorial Hospital & Chang Gung University, Taoyuan 333, Taiwan
Development Center for Smart Textile, National Taipei University of Technology, Taipei 106, Taiwan
Correspondence: naturewei@cgmh.org.tw (C.-W.L.); normanlu@mail.ntut.edu.tw (N.L.)
These authors contributed equally to this work.
*
†
ꢀꢁꢂꢀꢃꢄꢅꢆꢇ
ꢀꢁꢂꢃꢄꢅꢆ
0
0
0
Abstract: Homogeneous catalysts PtCl2[5,5 -bis-(n-ClCF2(CF2)3CH2OCH2)-2,2 -bpy] (2A) and PtCl2[5,5 -
bis-(n-HCF2(CF2)3CH2OCH2)-2,20-bpy] (2B), which contained short fluorous chains, were synthe-
sized and used in catalysis of hydrosilylation of alkynes. In these reactions the thermomorphic
mode was effectively used to recover these catalysts from the reaction mixture up to eight cycles by
taking advantage of heterogeneous phase separation at ice temperature. This kind of catalysis had
previously been observed in fluorous catalysts of platinum containing about 50% F-content, but in
this work the percentage of F-content is decreased to only about 30%, by which we termed them as
“very light fluorous”. Our new type of catalyst with limited number of F-content is considered as
the important discovery in the fluorous technology field as the reduced number of fluorine atoms
will help to be able to comply the EPA 8-carbon rule. The metal leaching after the reaction has been
examined by ICP-MS, and the testing results show the leaching of residual metal to be minimal.
Additionally, comparing these results to our previous work, fluorous chain assisted selectivity has
been observed when different fluorous chain lengths of the catalysts are used. It has been found
Citation: Chiu, C.-F.; Ho, J.-H.;
Tessema, E.; Lu, Y.; Shen, C.-R.; Lin,
C.-W.; Lu, N. Short-Chained Platinum
Complex Catalyzed Hydrosilylation
under Thermomorphic Conditions:
Heterogeneous Phase Separation at
Ice Temperature. Molecules 2021, 26,
378. https://doi.org/10.3390/
molecules26020378
Received: 19 December 2020
Accepted: 9 January 2021
Published: 13 January 2021
that there exists fluorous chain assisted better selectivity towards β-(E) form in the Pt-catalyzed
Publisher’s Note: MDPI stays neu-
tral with regard to jurisdictional clai-
ms in published maps and institutio-
nal affiliations.
hydrosilylation of non-symmetric terminal alkyne when the Pt catalyst contains short fluorous chain
(i.e., 4 Cs). Phenyl acetylenes showed the opposite regioselectivity due to pi-pi interaction while using
the same catalyst via Markovnikov’s addition to form terminal vinyl silane, which is then a major
product for Pt-catalyzed hydrosilylation of terminal aryl acetylene with triethylsilane. Finally, the
kinetic studies indicate that the insertion of alkyne into the Pt-H bond is the rate-determining step.
Copyright: © 2021 by the authors. Li-
censee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and con-
ditions of the Creative Commons At-
tribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Keywords: heterogeneous separation; catalyst; fluorous; hydrosilylation; platinum; thermomorphic;
recovery; selectivity
Molecules 2021, 26, 378. https://doi.org/10.3390/molecules26020378
https://www.mdpi.com/journal/molecules

Molecules 2021, 26, 378
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1. Introduction
Developing recyclable catalysts, able to reduce the waste of expensive transition metals
is one of the important issues in sustainable research. Generally, homogeneous catalysts
have good catalytic activity but they have limitation on separation catalytic recovery [1],
whereas heterogeneous catalysts are easily recyclable but with low catalytic activity [2–4].
A valuable method, called thermomorphic system provides a good resolution which makes
the catalyst dissolve in one condition but precipitate in another. Using the special solubility
selectivity of fluorous chain-containing metal complex [5,6] is very promising for the
catalytic thermomorphic system in the development of fluorine chemistry [7].
Many polyfluorinated chain-containing metal complexes are used in the fluorous
biphasic system (FBS) [8] which is an immiscible two-solvent system having one fluo-
rous solvent and a common organic one. After reaction completion, the fluorous chain-
containing metal complexes can be easily extracted from the fluorous solvent while the
other organic products stay in organic layer. To ensure the good solubility for fluorous
chain-containing compounds soluble in fluorous solvents, “heavy fluorous content” [9]
(more than 60% fluorine content, F-content) is required. This may result in a big draw-
back [10]; that is the need for expensive fluorous starting material and the solvent. To
reduce the F-content of compounds and fluorous solvent, an alternative way is to use
the different solubility of “light fluorous compounds” (less than 60% of F-content) [5,11]
between high and low temperature in a common organic solvent. In this method, a fluorous
chain-containing metal catalyst could be soluble at high temperature during the catalytic
reactions, but insoluble at room temperature (or lower temperature) for the recovery of
catalysts via a simple liquid-solid separation [12–17]. This is a typical application of “light
fluorous” metal catalysts in the so-called “thermomorphic condition”.
A variety of fluorous chain-containing metal complexes have been synthesized in our
laboratory and studied for the possible applications [18,19]. In 2016, we have demonstrated
the first example of using a fluorous chain-containing Pt complex with heavy fluorine
content {[PtCl2[5,50-bis-(n-C11F23CH2OCH2)-2,20-bpy] (3a), with 53% F-content for the Pt
catalyst} successfully catalyzed the hydrosilylation of alkynes in dibutyl ether (DBE) under
thermomorphic condition [19]. The results of the catalytic hydrosilylation reaction showed
high reaction yields, good turnover numbers and good recovery of the catalyst for up to
8 times of re-usage with very low leaching level of Pt (ca. 0.001%).
The hydrosilylation of alkynes has been performed with a variety of metal catalysts,
including Pt, Ir, Ru, Rh, and Co complexes, and usually produced three possible products,
α, β-(E) and β-(Z) isomers [20–29]. Generally, β-(E) is the thermo-dynamically favored
isomer and dominates in most researches using aliphatic and aryl alkynes, such as Lewis’s
work using Karstedt’s Pt catalyst [30], Marko’s work using N-heterocyclic carbene Pt(0)
catalysts (>95% yield) [31], Ge’s work using bisphosphine Co catalysts (60–90% yield) [32],
Jesus’s work using water-soluble N-heterocyclic carbene Pt(0) Complexes as a recyclable
catalyst (58–97% yield) [33,34], and Mata’s work using a recoverable Pt catalyst immobi-
lized on the surface of graphene (80–99% yield) [35]. Additionally, Chauhan and Sarkar’s
work using Pt-nanoparticle catalyst (95–98% yield) [36] and Cai’s work using a reusable
K2PtCl4/Xphos-SO3Na/PEG-400/H2O system (72–93% yield) [37] were reported to be
efficient and recyclable to give β-(E) vinylsilane. However, α isomer has also been achieved
to be the major product in few studies, such as Corma’s work, which only presented for
aryl acetylenes, using ligand-free Pt3 cluster catalyst (65–93% yield) [38], Trost’s work
using pentamethylcyclopentadiene Ru catalysts (61–92% yield) [39], and Huang’s work
using iminopyridine-oxazoline Co catalyst (55–95% yield) [40]. Additionally, Mori’s work
reported RhI-based catalyst which gave the β-(Z) isomer as a dominant product for both
aliphatic and aryl alkynes [41]. This study, which is focused on recoverable catalysis, suc-
cessfully developed a new recyclable Pt catalyst 2A under thermomorphic condition to
afford only two isomeric products,
α
and
β-(E) isomers, with better yield (>99%), where
the major products usually being -(E) isomer for the aliphatic alkynes and
β
α
-vinylsilanes

Molecules 2021, 26, 378
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for the aryl alkynes in the hydrosilylation of terminal alkynes. All the results with usual
features are discussed below.
It is important [42] that we could further lower the F-content of catalyst, in a way
that its F-content is even lower than that of so-called “light fluorous” catalyst; and is
without compromising the separation effectiveness, so they become readily adapted to the
conventional chemical and biochemical processes. In this work, the even shorter fluorous
chain-containing platinum catalysts, [PtCl2(5,50-bis(CH2OCH2C4F8Cl)-2,20-bpy)] (2A) and
[PtCl2(5,50-bis(CH2OCH2C4F8H)-2,20-bpy)] (2B) with the even lower fluorine content (i.e.,
31.0 and 33.4% F-content for 2A and 2B, respectively.) have been synthesized and been ap-
plied to catalyze the hydrosilylation reactions of internal and terminal alkynes. To the best
of our knowledge, this is the first example of the application of very short polyfluorinated
Pt complexes as effective, recoverable hydrosilylation catalysts under thermomorphic
condition showing heterogeneous phase separation at ice temperature. These “very light
fluorous” Pt complexes 2A and 2B feature on homogeneously catalyzing reaction at high
temperature in common organic solvent and turning to the heterogeneous precipitation
at lower temperature under thermomorphic condition. Taking into consideration of their
good catalytic capabilities and good thermal stability, these catalysts could be regarded as
the very good alternatives to most of the homogeneous catalysts.
2. Results and Discussion
2.1. Catalyst Synthesis
The preparation of ligands bis-5,50-(n-ClCF2(CF2)3CH2OCH2)-2,20-bpy (1A) and bis-
5,50-(n-HCF2(CF2)3CH2OCH2)-2,20-bpy (1B) followed a literature procedure [43]. The lig-
and of 1A or 1B has the lower F-content (wt. %), which is 42.6 and 47.2%, respectively. The
reaction of fluorinated bipyridine (bpy) ligands, 1A, 1B, with K2PtCl4 in DMSO, as shown in
0
0
Scheme 1, resulted in the synthesis of Pt complexes PtCl2[5,5 -bis-(n-ClC4F8CH2OCH2)-2,2 -
bpy] (2A) and PtCl2[5,50-bis-(n-HC4F8CH2OCH2)-2,20-bpy] (2B) as red solids, respectively.
Compounds of 2A and 2A exhibit the F-content being 31.0 and 33.4%, respectively; and are
soluble in Bu2O at 120 ◦C forming a red color solution. However, compounds 2A and 2B
are insoluble in Bu2O at 25 ◦C (see Figures S3 and S4 & Scheme S1). Complexes of 2A and
2B are also abbreviated as 55-8FCl-PtCl2 and 55-8FH-PtCl2, respectively.
Scheme 1. Synthesis of the short fluorous chain Pt complexes.
2.2. Recoverable Pt Complex-Catalyzed Hydrosilylation of Alkynes
The fluorinated short-chained Pt complex 2A and 2B were then examined for the
following experiments to catalyze the addition of HSiEt3 (
alkyne 5-decyne ( ); (b) terminal alkynes 1-decyne ( ), 1-hexyne (
); and (c) aromatic terminal alkynes (8–
3
) to (a) symmetrical internal
) and functionalized
10) in the following
4
5
6
terminal propargylic alkyne (
hydrosilylation reactions.
7
(a) Symmetrical internal alkyne
The Pt catalyst (2A or 2B)-catalyzed hydrosilylation of 5-decyne (
3) under thermomorphic condition was successfully carried out to afford product 4a in
4
) with triethylsilane
(
quantitative conversions, as shown in Scheme 2, whereas no product 4a could be found in
the reaction without using Pt catalyst for 24 h. The best reaction condition for the catalyst 2A
◦
was optimized at 120 C for 2 h via the GC-MS examination of the reaction while the NMP
was used as the internal standard. The quantitative conversion of the hydrosilylations were
still observed even over the eight cycles of Pt catalyst recycling almost without decreasing

Molecules 2021, 26, 378
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the activity under the thermomorphic condition (Table 1). The similar catalytic effect on
the converting yield is also shown by Pt catalyst 2B whose structure is to have H atom to
replace Cl atom of 2A at the terminal of fluorous chains.
Scheme 2. The Pt catalyst (2A or 2B)-catalyzed hydrosilylation of 5-decyne (4) with triethylsilane (3)
under thermomorphic condition.
Table 1. Hydrosilylation reactions of 5-decyne (4) and triethylsilane (3) in the presence of 2A and
2B catalysts.
55-8FCl-PtCl2 (2A)
Time (h)
Yield (%) a
55-8FH-PtCl2 (2B)
Time (h)
Yield (%) a
Run
1
2
3
4
5
6
7
8
2
2
2
2
2
2
2
2
100
99 (89)
100 (94)
100
100
100
2
2
2
2
2
2
2
2
100
100
94
100 (91)
100 (94)
90
100
100
100
96
Reaction conditions: Temp = 120 ◦C; cat 2A or 2B 1 mol%,
4
(276 mg, 2 mmol),
3
(232 mg, 2 mmol), solvent: 2 mL.
a: Based on GC yield; isolated yields are given in parentheses.
Generally, catalysts with high F-content have good performance under thermomorphic
0
0
condition, e.g., PtCl2[5,5 -bis-(n-C11F23CH2OCH2)-2,2 -bpy] (55-23F-PtCl2) reported in our
previous work (with C11F23 moiety, %F = 53) [19], but the catalyst 2A here only containing
“very-light fluorous” chain (e.g., C4F8, %F = 31) still showed the impressive catalytic
activity and efficient recovery under thermomorphic condition (Figures S1 and S3) shown
in Table 1.
Generally speaking, typical Pt-based catalysts for the hydrosilylation of alkynes can
be used at significantly lower Pt/substrate ratios than 1 mol% loading. We mainly use
1 mol% of catalyst 2A loading because the scope of this study is on recycling and reuse of
catalyst. The hydrosilylation of 5-decyne (4) with triethylsilane (3) was also reported by F.
Alonso’s group using Pt/TiO2 as the catalyst by using more stringent catalytic loading of
0.25 mol% [44]. They showed catalytic results under very short reaction time (less than 2 h)
at first two catalytic reaction cycles, but the catalyst’s activity was significantly decreased
to make the third-cycle reaction taking 3 h for the same conversion and the fifth-cycle
reaction giving only 62% conversion after 24 h. In contrast, the fifth-cycle hydrosilylation in
our work still had very good performance of 99.5% conversion (entry 5 in Table 1), which
indicates that Pt catalyst 2A is both very efficient and robust. The Pt catalyst 2A-catalyzed
hydrosilylations of 5-decyne (
4
) with triethylsilane (
3
) in Bu2O have also been studied
◦
kinetically at 120 and 130 C. These two sets of data points are shown in Section S3 in
Supplementary Materials. In both cases, the integrated rate law derived from the alkyne
concentration vs time plots is ln[5-◦decyne] = ln[5-decyne]0-kt, with k = 0.069 (R2 = 0.95) &
◦
◦
0.099 (R2 = 0.99) at 120 C and 130 C, respectively. [Note: ln[5-decyne]0 = 0]; at 130 C the
derived ln[5-decyne]0 value is very close to 0]. The first reaction order with respect to the
alkyne suggests that the insertion of the latter into the Pt-H bond is the rate-determining
step, in agreement with the recent results reported by Kuhn’s group [45]. These two
kinetically monitored reactions at 0.5 h show the respective turnover frequencies (TOF) are
174 and 198 h−1. These data show that 2A is recoverable, robust and catalytically effective.

Molecules 2021, 26, 378
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The Pt catalyst 2A-catalyzed hydrosilylation of 5-decyne (
4
) and dimethylphenylsilane
(
30) was also carried out in a shorter reaction time (ca. 40 min) to afford only E-form product
of 4c based on the GC-MS analysis, as shown in Scheme 3. The good recycling results under
the thermomorphic condition were also confirmed by the nearly quantitative conversion of
the hydrosilylation catalyzed by the reused Pt catalyst for up to eight cycles (Table 2) with
very good turnover number (TON = ~100).
Scheme 3. The Pt catalyst 2A-catalyzed hydrosilylation of 5-decyne (
(3 ) under thermomorphic condition.
4) with dimethylphenyl-silane
0
0
Table 2. Hydrosilylation reactions of 5-decyne (
4
) and dimethyl-phenylsilane (
3
) under thermomor-
phic condition.
Cycle
Time (h)
Yield (%) a
1
2
3
4
5
6
7
8
1
1
1
1
1
1
1
1
100
98
100 (97)
100
100
100
100 (97)
100
Reaction conditions: T = 120 ◦C, cat. 2A: 1 mol%, 4 (276 mg, 2 mmol), 30 (272 mg, 2 mmol), solvent: 2 mL. a: Based
on GC yield; isolated yields are given in parentheses.
(b) Terminal alkynes
b.1. Two terminal alkyl acetylenes
The Pt complex 2A-catalyzed hydrosilylation of triethylsilane (
[i.e., 1-decyne ( ) or 1-hexyne ( )] under thermomorphic mode is shown in Scheme 4. The
hydrosilylation of 1-decyne ( ) with triethylsilane ( ) afforded two products, triethyl(dec-1-
3) with terminal alkyne
5
6
5
3
en-2-yl)silane (5a) and (E)-triethyl(dec-1-en-1-yl)silane (5b) with a GC-MS or NMR method
to monitor the reaction and to determine the products under thermomorphic condition.
This hydrosilylation also showed very good recycling results under thermomorphic condi-
tion. The structure of 5a and 5b were identified by the 1H-NMR spectrum of their mixture
(see Figure S7). The signals of Ha and Ha’ of 5a are shown as two doublet peaks at 5.2
and 5.6 ppm with a coupling constant of 2.7 Hz, which is consistent to that of geminal
alkenyl protons. For 5b, the Hb’ shows a doublet-triplet splitting peak and the Hb shows a
doublet peak with a coupling constant of 18.9 Hz, which represents for the alkenyl protons
at the trans position. The ratio of 5a and 5b determined from the integration of 1H-NMR
spectrum equals to 1:2, which is almost similar to the ratio from GC-MS method (1:1.82)
(see entry 5 in Table 3).
Scheme 4. The Pt complex 2A-catalyzed hydrosilylation of 1-decyne (5) or 1-hexyne (6) with triethyl-
silane (3) under thermomorphic condition.

Molecules 2021, 26, 378
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Table 3. Hydrosilylation reaction of 1-decyne (5) and triethylsilane (3) under thermomorphic condition.
Cycle
Time (h)
5a:5b
Yield (%) a
1
2
3
4
5
6
7
8
1
1
1
1
1
1
1
1
1:1.58
1:1.67
1:1.48
1:1.77
1:1.82
1:1.74
1:1.40
1:1.58
100
100 (96)
100 (92)
100
100 (92)
100
100 (99)
100 (91)
Reaction conditions: T = 120 ◦C, cat. 2A 1 mol%, 5 (276 mg, 2 mmol), 3 (232 mg, 2 mmol), solvent: 2 mL. a: Based
on GC yield; isolated yields are given in parentheses. The other terminal alkyne (1-hexyne (6)) recycling data are
shown in Table S1 in Supplementary Materials.
The other terminal alkyne, 1-hexyne (
with triethylsilane ( ) in the presence of Pt catalyst 2A successfully (Scheme 4). The reaction
was completed within 30 min to produce two isomers -form 6a and -(E)-form 6b whose
1H-NMR spectrum shows similar characteristic peaks (see Figure S8) to that of
-form 5a
and -(E)-form 5b. The signals for Ha and Ha’ of 6a are 5.3 ppm (dt, J = 3.3, 1.2 Hz) and
6) also underwent the hydrosilylation reaction
3
α
β
α
β
5.6 ppm (dt, J = 3.3, 1.5 Hz); and the signals for Hb and Hb0 of 6b are 5.5 ppm (dt, J = 18.6,
1.5 Hz) and 6.0 ppm (dt, J = 18.6, 6.3 Hz), respectively. As shown in entry 1 of Table S1, the
ratio of 6a and 6b is approximately 1:4.7 estimated by a GC-MS method.
b.2. One functionalized terminal alkyl acetylene (propargyl alcohol)
In Scheme 5, the hydrosilylation of 2-methylbut-3-yn-2-ol (7), a terminal alkyne with a
bulky substituent (hydroxyisopropyl) with triethylsilane ( ) for 1 h afforded two isomers,
3
α
-form 7a and β-(E)-form 7b in 99.4% yield with an estimated ratio of 1:2.1 from GC data,
and/or 1:2.3 from 1H-NMR spectra. The good recycling results for this reaction were shown
in Table 4. When comparing with the previously reported long fluorous chained platinum
complex (
α:β = 1:2) [19], a slightly better selectivity was observed in this work by using Pt
catalyst 2A (1:2.3). Although the heterogeneous catalyst PtO/PtO2-Fe3O4 in literature [46
]
showed a better selectivity for 7a and 7b (1:3.5), it is worth mentioning that the Pt complex
2A in this work still has good selectivity among a homogeneous type of catalysts.
Scheme 5. The Pt-catalyzed hydrosilylation reaction of 2-methylbut-3-yn-2-ol (7) and triethylsilane
(3) under thermomorphic condition.
Table 4. Hydrosilylation reaction of 2-methylbut-3-yn-2-ol (7) and triethylsilane (3) under thermo-
morphic condition.
Cycle
Time (h)
7a:7b
Yield (%) a
1
2
3
4
5
6
7
8
1
1
1
1
1
1
1
1
1:2.1
1:2.1
1:2.0
1:2.2
1:2.1
1:1.9
1:2.0
1:2.0
100 (96)
99
99 (92)
99
98
100
100
99
Reaction conditions: T = 120 ◦C, cat. 2A 1 mol%, 7 (168 mg, 2 mmol), 3 (232 mg, 2 mmol), solvent: 2 mL. a: Based
on GC yield; isolated yields are given in parentheses.

Molecules 2021, 26, 378
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(c) Three terminal aryl acetylenes
In Scheme 6, the Pt catalyst 2A-catalyzed hydrosilylation of phenylacetylene (
8
) with
triethylsilane (3) for 1~3 h under thermomorphic condition afforded two isomers, α-form
8a and -(E)-form 8b with an estimated ratio of 2:1 according to GC-MS analysis. The
characteristic 1H-NMR signals (see Figure S9
for the geminal alkenyl protons of -form
8a appear at 5.6 ppm (d, J = 3 Hz) and 5.9 ppm (d, J = 3 Hz), and the signals for the trans
β
)
α
position protons of (E)-form 8b show at 6.4 ppm (J = 18.9 Hz) and 6.9 ppm (J = 19.5 Hz)
Most of the ratios of 8a and 8b determined by the integration of 1H-NMR spectrum are
close to 2:1.
.
Scheme 6. The Pt complex 2A-catalyzed hydrosilylation of phenyl acetylenes (
8~10) with triethyl-
silane (3).
Which is consistent to the ratio from GC-MS data in Table 5. Interestingly, the major
product for the hydrosilylation of the terminal aryl acetylene ( ) is thermodynamically
unfavored -form 8a, whereas the major products for the alkyl acetylenes ( and ) are
thermodynamically favored -(E)-form 5b 6b and 7b. The selectivity of ratio of 8a 8b
8
α
5,
6
7
β
,
:
decreased after 6 runs is because some of the catalysts start to degrade during the course of
repeated reactions.
Table 5. Hydrosilylation reaction of phenylacetylene (8) and triethylsilane (
3) under thermomor-
phic condition.
Cycle
Time (h)
8a:8b
Yield (%) a
1
2
3
4
5
6
7
8
2
2
2
2
2
2
2
2
2.02:1
2.25:1
2.26:1
2.25:1
2.21:1
2.20:1
1.86:1
1.80:1
99 (92)
99 (96)
99
100 (98)
100
100
100
100
Reaction conditions: T = 120 ◦C, cat.2A 1 mol%, 8 (204 mg, 2 mmol), 3 (232 mg, 2 mmol), solvent: 2 mL. a: Based
on GC yield; isolated yields are given in parentheses.
When we compare the efficiency of our catalyst 2A with a heterogeneous molecular
complex immobilized on the surface of graphene, catalyst 2A showed better catalytic
efficiency at the elevated temperature. Mata [35] and his colleagues used 1 mol% catalytic
loading of their catalyst in the similar reactions to obtain 40% yield after 3 h where TON
and TOF are 40 and 13, respectively. They have further optimized the reaction and used
0.5 mol% loading to obtain 94% yield after 20 h. Where TON and TOF are 188 and 9.4,
respectively. However, we have obtained on average 100% yield in 2 h with TON and TOF
values of 100 and 50, respectively.
According to the literatures, which isomer being the major product for the hydrosily-
lation of phenylacetylene depends on the different catalysts. The thermodynamically stable
β
-(E)-isomer was the major product when the hydrosilylation was catalyzed with a homo-
◦
geneous Karstedt’s catalyst at 60 C for 1 h, and the product ratio was
β-(E):β-(Z):
α
iso-
mers = 81:1:18 [30]. However, the
α isomer was the major product when it was catalyzed by a

Molecules 2021, 26, 378
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◦
heterogeneous catalyst Pt/CeO2 at 70 C for 18 h [44] with the product ratio of
β-(E):α
= 26:74
and the conversion 39% for THF and 50% for water as the solvents, respectively. Compara-
tively, using the Pt catalyst 2A in this work which was homogeneous under thermomorphic
mode, but provided thermodynamically unfavored α-form as the major product with better
conversions (mostly more than 99%) and shorter reaction time (1~3 h).
Lastly, to further understand this unusual product selectivity, two more substituted
phenyl acetylenes with electron-withdrawing fluoro group and electron-donating methyl
group were brought to this 2A catalyzed hydrosilylation under thermomorphic mode. The
hydrosilylation of 4-fluorophenylacetylene (
as the major product in 99% high yield with the product ratio of 9a
GC) (Table S2). Similarly, the hydrosilylation of 4-methylphenylacetylene (10) at 120 C for
9 α-form isomer
) at 120 ◦C for 4~5 h afforded
:
9b = 2.54:1 (estimated by
◦
2~5 h also produced
ratio of approximately 10a
hydrosilylation reactions of either 4-fluorophenylacetylene (
10) with triethylsilane ( ) under thermomorphic conditions are shown Tables S2 and
S3 in Supplementary Materials. No matter what kind of three substituents connected
on the phenyl ring at para position, the thermodynamically less favored -form isomer
α
-form isomer as the major product in 99% high yield with the product
10b = 2.13:1 estimated by GC (entry 4, Table S3). The results of
) or 4-methylphenylacetylene
:
9
(
3
α
would be the major product. Thus, Figure 1 and the related discussion below also explain
the observed moderate regioselectivity of the 2A-catalyzed hydrosilylations of aryl and
aliphatic acetylenes.
To understand the better product ratio from the Pt complex 2A-catalyzed hydrosilyla-
tion (short-fluorous-chains), a plausible mechanism containing the geometry of Pt complex
was proposed. The optimized structure of 2A in the gaseous phase has been obtained by
DFT theoretical calculation, showing the two fluorous side-chains whose -CH2OCH2-Rf
0
moieties can form the two five-membered rings at the both sides of 5,5 -substituted bipyri-
dine to extend the metal planarity (in Figure 1 and Figure S10 of Supplementary Materials).
Similar type of extended the Pt metal planarity (with U-shaped like arrangement) has
been found on the experimental data of 55–8FH-PtI2 (see Figure S11) in our previous re-
search [47]. This optimized 2A arrangement also shows the intramolecular five-membered
ring and other weak interactions (see Figure S10); and also be observed to be similar to that
of the complexes 55–4FH-MX2, where X = Br or I; M = Pt, with the loop structure reported
by our group [48] (see Figure S12).
As shown is Figure 1 which is similar to Chalk-Harrod mechanism, the proposed
mechanism for 2A-catalyzed hydrosilylation of terminal aliphatic alkyne with triethylsilane
is described in a 3D-view instead of 2D-view of a well-known Chalk-Harrod mechanism.
Firstly, in species I the 2A catalyst is believed to appear in the reduced form, Pt(0) [49
]
at the elevated temperature. Besides the planar Pt(bpy) core, the Pt complexes which
contain two intramolecular five-membered ring in the species I, II, III and IV can extend its
planarity with slight U-shaped structure. The Et3SiH is oxidatively added to [Pt], followed
by coordination of the alkyne and insertion to Pt-H bond. Thus, the electronic effect due
to the polarization of an alkyne in hydrosilylation would direct the hydride addition to
the more electropositive C-atom (in II). After the oxidative addition of silane, the alkyne
is shown by approaching from the top of the Pt(bpy)-based molecular plane. When the
alkyne (the 2nd reactant) has been attached to the Pt, this step of migration-insertion shows
that the R group of the alkyne (III at bottom) has been forced to keep away from the
silyl-group side of the metal complex (in IV) which then leads to generate
the major product. This addition shows the anti-Markovnikov’s selectivity. This proposed
mechanism reasonably explains the better product ratio of -(E) to in 1-decyne ( ),
1-hexyne ( ) and propargyl alcohol ( ) in the hydrosilylations catalyzed by Pt catalyst 2A in
this study. However, if the R group is the aromatic moiety, then the bond axis of the linear
aryl acetylene molecule (H-C
C-R) rotates more than 90o with respect to Pt-b axis (which
is the molecular plane normal) (see Figure 1). For example, in an extreme case, if the tilting
angle is equal to 180◦, then it is like the linear molecule is exactly flipped over (R-C
C-H).
Such a phenomenon occurs possibly due to steric reason and other weak interactions (e.g.,
β-(E) form as
β
α
5
6
7
≡
≡

Molecules 2021, 26, 378
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pi-pi interaction), when linear aromatic alkyne in species III is attached to the Pt center.
Thus, 2A-catalyzed hydrosilylation of terminal aryl acetylenes with triethylsilane gives rise
to the α isomer as the major product.
Figure 1. The proposed mechanism for 2A-catalyzed hydrosilylation of terminal (alkyl) alkyne with
triethylsilane. (Note: H is labeled in red color).
2.3. Detection of Metal Recovery by ICP-MS
After discussing the hydrosilylation reaction of alkyne substrates, we randomly used
ICP-MS to detect the leakage of metal catalysts, as shown in Table 6. The quantity of
residual Pt metal present in the solution was analyzed, taking random samples among the
product solutions resulting from the thermomorphic hydrosilylation. Only very low Pt
leaching was observed in solution from the complex 2A- and 2B-catalyzed hydrosilylations
under thermomorphic conditions. The residual platinum content in the product is only
minimal since the recovery rate is greater than 99 %. Looking at the leaching test results,
whether it is for 2A or 2B, the measured platinum content is in the ppb level even after
the 8 times of repeated recycling. It can be concluded that the metal catalyst used in this
experiment not only effectively catalyzes hydrosilylation, but also easily achieved with
almost no Pt leaching during the recycling processes.

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Table 6. Detection of platinum metal leakage by ICP-MS.
Ppb a
Recovery (%)
b
Leaching Level (10–4
)
Table (& Cycle)
Catalyst
1–2
1–3
1–7
1–8
1–2
1–3
1–7
1–8
2–4
2A
2A
2A
2A
2b
2B
2B
2B
2A
2A
2A
2A
2A
2A
2A
2A
2A
517.5
444.7
137.1
41.6
21.7
31.3
56.6
43.6
29.9
107.5
79.4
60.7
98.0
1753.0
2347.0
276.5
805.7
6.63
5.70
1.76
0.53
0.28
0.40
0.72
0.56
0.38
1.38
1.02
0.78
1.26
22.50
30.10
3.54
10.30
99.93
99.94
99.98
99.99
99.99
99.99
99.99
99.99
99.99
99.98
99.98
99.99
99.98
99.77
99.69
99.96
99.89
3–2
3–4
3–6
S1–4 c
S1–7 c
S1–8 c
4–4
5–4
a: (in ppb) detected from ICP-MS analysis for every 5 mL of sample solution which is diluted from 2 mL
reaction mixture. b: The Pt leaching level is calculated as follows: taking entry 1–2 (Table 1- Cycle 2) for example:
(517.5 ppb × 5 mL)/(0.02 mmol Pt) = 517.5
×
(mg Pt/103 L)
×
5
×
(10–3 L)/(2 × 10–2 × 195 mg Pt) = 6.63 × 10−4
.
c: These three entries are shown in Table S1 in Supplementary Materials.
In order to evaluate the effect of a series of fluorous chain on the Pt catalyst recovery, the
fluorinated moieties of Rf = CF3, C4F8Cl (C4F8H), C8F16H and C11F23 in the fluorous chain
have been investigated for the systematic purpose. In other words, for the fluorous chains with
Rf = CF3 and C8F16H moieties which are from respective [PtCl2(5,50-bis(CH2OCH2CF3)-2,20-
0
0
bpy)] (2C) and [PtCl2(5,5 -bis(CH2OCH2C8F16H)-2,2 -bpy)] (2D) complexes have also studied
to give a trend for the series (see Section S7 in Supplementary Materials). When Rf = CF3 group,
it has been found that 55-3F-PtCl2 (2C) is totally soluble in DMF and moderately soluble in
Bu2O. The images of these solubility properties are shown in Section S7 of Supplementary
Materials (see Figure S13a,b). Thus, complex 2C with one carbon fluoro-chain which is so short
that it cannot give the useful heterogeneous phase separation property at room temperature
for the recycling studies here. When Rf = C8F16H group which is sparingly soluble in Bu2O
ether (solubility image is shown in Figure S14 in Supplementary Materials).
Thus, 55-16FH-PtCl2-catalyzed hydrosilylations of 5-decyne with HSiEt3 at 120 ◦C
under thermomorphic mode have also been carried out. These results shown in Table S4
in Supplementary Materials indicate that these 55–16FH-PtCl2
lations can take slightly longer than 3 h to complete. Thus, by comparing the reactivities
from a series of Pt metal complexes which are 55-8FCl-PtCl2 2A), 55-16FH-PtCl2 (see
Section S7.2, Table S4 in Supplementary Materials) and 55-23F-PtCl2 19], the rate due to
(2D)-catalyzed hydrosily-
(
[
the steric reasons follows the trend: the shorter the chain of fluorous catalyst, the faster the
hydrosilylation.
3. Experimental Section
3.1. General Procedures
HP 6890 GC containing a 30 m 0.250 mm HP-1 capillary column with a 0.25 mm
stationary phase film thickness was used to censor the reaction. The same GC instrument
with a 5973 series mass selective detector was used to Acquire GC/MS data. The flow
rate was 1 mL/min and splitless. Samples analyzed by fast atom bombardment (FAB)
mass spectroscopy were done by the staff of the National Central University (Taoyuan,
Taiwan) mass spectrometry laboratory. The amounts of residual Pt samples were analyzed
by ICP-MS. Infra-red spectra were obtained on a Perkin Elmer RX I FT-IR Spectrometer.
NMR spectra were recorded on Bruker AM 500 and Joel AM 200 using 5 mm sample tubes.
CD3OD, CD2Cl2, CDCl3, deuterated DMF and deuterated DMSO were the references

Molecules 2021, 26, 378
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1
for both H- and 13C-NMR spectra; and Freon® 11 (CFCl3) was the reference for 19F
NMR spectra.
3.2. General Procedures in Catalytic Hydrosilylation Reaction and Recovery
In a typical run, an alkyne (2 mmol) and silane (2 mmol) were charged into 10 mL
reaction tube containing a magnetic stirrer bar, then the Pt catalyst (1 mol%) and followed
by dibutyl ether, DBE, solvent (2 mL). Then the reaction mixture was set to react at 120 ◦C
for the given period of time before GC/MS analysis was done to confirm the completion of
the reaction. Once the catalytic recovery was done, the pure product was isolated by using
CH2Cl2/water extraction and the CH2Cl2 layer was pumped under reduced pressure to
obtain the pure product. The product was finally analyzed by using 1H-NMR spectroscopy.
The Pt-catalyzed hydrosilylation reactions of all the alkyne substrates with
3 were
carried out under the thermomorphic condition that effectively confirmed the practicability
of reutilizing the catalyst in Bu2O solvent. Every round the catalytic reaction was performed
◦
at 120 C under N2 gas. At the end of each run, the product mixtures were put into freezer
(0 ◦C) for about 5 min, and then centrifuged to separate the catalyst and reaction mixture
(see Scheme S1 in Supplementary Materials). After catalyst was recovered by decantation
and washed three times by the same solvent, it was again supplied with the same amounts
of Bu2O solvent, the alkyne substrate, and HSiEt3 to continue to the next round. The
products were tracked with GC-MS and 1H-NMR, using NMP as internal standard until
the end of the reaction was confirmed.
3.3. Starting Materials
Chemicals, reagents, and solvents employed were commercially available and used
as received. H(CF2)4CH2OH and Cl(CF2)4CH2OH were purchased from either Aldrich
or SynQuest.
3.4. Preparation of Platinum Complexes
0
The reaction of K2PtCl4 with fluorinated bipyridine derivatives, bis-5,5 -(n-C4F8ClCH2OCH2)-
2,20-bpy (01A) and bis-5,50-(n-C4F8HCH2 OCH2)-2,20-bpy (1B), resulted in the synthesis of
0
0
PtCl2[5,5 -bis-(n-C4F8ClCH2OCH2)-2,2 -bpy] (2A) and PtCl2[5,5 -bis-(n-C4F8HCH2OCH2)-
2,20-bpy] (2B), as red solids. 1A or 1B (10.0 mmol; its synthesis see Supplementary Materi-
als), K2PtCl4 (11.0 mmol) and DMSO (2 mL) were charged into 50 mL round-bottomed flask.
The reaction was stirred under nitrogen at room temperature for 4 h, and the complexes
2A and 2B would then precipitate from the reaction mixture [50–53]. After collection of the
precipitates, water and Et2O were used to wash the red solids for several times, and the
yields were 87% and 85%, for 2A and 2B, respectively.
3.5. Analytical Data for Two Ligands and Their Platinum Metal Complexes (1A, 1B, 2A, 2B)
55-8FCl-bpy (1A). Yield: 90%. m.p.: 75 ◦C. FT-IR (cm−1): v (bpy, m) 1600, 1557, 1466; v
1
(CF2 stretch, s) 1182, 1112. H-NMR (300 MHz, DMSO-d6, rt):
δ (ppm) 8.65 (d, J =1.5 Hz,
2H, H6), 8.39 (d, J = 8.4 Hz, 2H, H3), 7.90 (dd, J = 8.1 Hz, J = 2.1 Hz, 2H, H4), 4.78 (s, 4H,
bpy-CH2), 4.28 (t, J = 7.35 Hz, 4H, -CH2CF2-); 13C-NMR (125 MHz, DMSO-d6, 350 K):
δ
(ppm) 192.3, 186.2, 174.3, 170.5, 157.8 (10C, bpy), 161.6–144.2 (-C4F8Cl), 108.4 (bpy-
CH2O-), 103.9 (-CH2CF2-); 19F-NMR (470 MHz, DMSO-d6, 350 K):
(ppm) 68.4 (t,
120.2 (m, 4F, -CF2CF2Cl), 122.1
δ
−
J = 14.1 Hz, 4F, -CF2Cl),
−
118.8 (t, 4F, -CH2CF2),
−
−
(s, 4F, -CH2CF2CF2-). 713 (M+), 463 (M+-CH2C4F8H), 447 (M+-OCH2C4F8H), 182 (M+-
(OCH2C4F8H)2), 91 (C6H5N).
55-8FH-bpy (1B). Yield: 80%. m.p.: 68 C. FT-IR (cm−1): v (bpy, m) 1598, 1558, 1469; v
◦
1
(CF2 stretch, s) 1159, 1126. H-NMR (300 MHz, CDCl3, rt):
δ (ppm) 8.62 (s, 2H, H6), 8.41
(d, J = 8.2 Hz, 2H, H3), 7.80 (d, J = 8.2 Hz, 2H, H4), 6.04 (tt, J = 51.9 Hz, J = 5.5 Hz, 2H,
CF2H), 4.70 (s, 4H, bpy-CH2), 3.99 (t, J = 14.68 Hz, 4H, -CH2CF2-); 13C-NMR (125 MHz,
CDCl3, 350 K):
71.9 (bpy-CH2O-), 67.0 (-
δ
(ppm) 121.0, 132.1, 136.5, 148.6, 155.9 (10C, bpy), 108.0–118.5 (-C4F8Cl),
H2CF2-); 19F-NMR (470 MHz, CDCl3, 350 K):
(ppm) 137.2
C
δ
−

Molecules 2021, 26, 378
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(t, J = 13.7 Hz, 4F, -CF2H),
−
119.5 (t, 4F, -CH2CF2),
−
125.4 (m, 4F, -CF2CF2Cl),
−
130.2 (s,
4F, -CH2CF2CF2-). GC/MS: 644 (M+), 429 (M+-CH2C4F8H), 413 (M+-OCH2C4F8H), 182
(M+-(OCH2C4F8H)2), 91 (C6H5N).
55-8FCl-PtCl2 (2A). Yield: 87%. Decomposed temperature = 315.5 C. FT-IR (cm-1): v
◦
(bpy, m) 1617, 1477; v (CF2 stretch, s) 1180, 1132, 1103. 1H-NMR (500 MHz, DMSO-d6,
rt):
J = 1.8 Hz, 2H, H4), 4.92 (s, 4H, bpy-CH2), 4.36 (t, J = 14.1 Hz, 4H, -CH2CF2-); 13C-
NMR (125 MHz, DMSO-d6, 350 K): (ppm) 155.8, 146.9, 138.7, 137.2, 123.6 (10C, bpy),
148.3–120.1 (-C4F8Cl), 70.1 (bpy-CH2O-), 66.8 (-
H2CF2-); 19F-NMR (470 MHz, DMSO-
d6, 350 K): (ppm) 67.9 (t, J = 14.1 Hz, 4F, -CF2Cl), -118.5 (t, 4F, -CH2CF2), 119.7 (m,
δ (ppm) 9.47 (d, J =1.8 Hz, 2H, H6), 8.56 (d, J = 8.1 Hz, 2H, H3), 8.32 (dd, J = 8.7 Hz,
δ
C
δ
−
−
4F, -CF2CF2Cl), -121.6 (s, 4F, -CH2CF2CF2-). HR-FAB: (M+, m/z): C22H1435Cl4F16N2O2Pt
calculated: 976.9202, found: 976.9207; C22H1435Cl337ClF16N2O2Pt calculated: 978.9185,
found: 978.9183; C22H1435Cl237Cl2F16N2O2Pt calculated: 980.9185, found: 980.9171.
55–8FH-PtCl2 (2B). Yield: 85 %. m.p.: 290 °C. FT-IR (cm−1): v (bpy, m) 1672, 1477; v (CF2
stretch, s) 1394, 1164, 1108. 1H-NMR (500 MHz, DMSO-d6, rt):
δ
(ppm) 9.49 (s, H6), 8.57
(2H, d, J = 8.2 Hz, 2H, H3), 8.33 (d, J = 8.2 Hz, 2H, H4), 7.05 (tt, J = 50.3 Hz, J = 5.6 Hz,
2H, HCF2-), 4.94 (4H, s, bpy-CH2), 4.33 (4H, t, J = 14.8 Hz, -
H2CF2-); 13C-NMR (125 MHz,
DMSO-d6, rt): (ppm) 156.0, 146.9, 139.0, 137.4, 123.9 (10C, s, bpy), 120.0–105.0 (8C, -C4F8H),
70.1 (2C, s, bpy-CH2), 66.6 (2C, t, J = 24.5 Hz, -CH2CF2-); 19F-NMR (470 MHz, DMSO-d6, rt):
(ppm) 119.7 (m, 4F, -CH2CF2-), 125.1 (s, 4F, -CH2CF2CF2-) 130.1 (m, 4F, -CF2CF2H),
C
δ
δ
−
−
,
−
−
138.8 (d, 4F, J = 49.6 Hz, -CF2H). HR-FAB: (M+, m/z) C22H1635Cl2F16N2O2Pt calculated m/z
908.9981, found 908.9985; C22H1635Cl37ClF16N2O2Pt calculated m/z 910.9952, found 910.9946;
C22H1637Cl2F16N2O2Pt calculated m/z 912.9922, found 912.9921.
4. Conclusions
Concerns for the environment and scarcity of resources is becoming a challenge
which motivates chemists to look for more economical and more ecofriendly process.
Therefore, developing a recoverable catalyst with a better activity, better selectivity, and
easier separation, with a better yield is everyone’s goal. Reported here, this work showed
effective catalysis by using shortest fluoro-chain complexes containing the (%)F-content
being less than 35 wt.%. The catalyst was very effectively recycled up to eight times for
all the experiments done, but almost without affecting its activity and selectivity. In these
reactions the thermomorphic mode was effectively used to recover these short fluorous
ponytailed catalysts from the reaction mixture up to eight cycles by using heterogeneous
◦
phase separation at 0 C. The product yield was also higher in every reaction run; sometimes
it reached to even 100%. The metal leaching studies via ICP-MS method showed that the
metal in the complex is effectively recovered throughout the catalytic cycles with very little
loss, which is almost negligible. Additionally, the kinetic studies have been carried out for
2A-catalyzed hydrosilylations of 5-decyne (
4
) with triethylsilane (
3
) in Bu2O at 120 and
◦
130 C. The results showed that the 1st order kinetics where the rate is directly proportional
to the concentration of 5-decyne. Thus, we suggest that the insertion of alkyne into the
Pt-H bond is the rate-determining step which agrees well with recent results reported by
Kuhn et al. [45]. Furthermore, the regioselectivity followed the Chalk-Harrod mechanism
as it undergoes the syn kind of reaction to give
α and β-(E) products, of which the β-(E)
was the major form for most of the cases.
Supplementary Materials: The following are available online at, Figures S1–S4: thermomorphic
property data, Figures S5 and S6: kinetic study, Figures S7–S9 1H-NMR spectra of hydrosilylation
products, Figures S10–S12: optimized structure from theoretical calculations, Tables S1–S4: recovery
and recycling study. Scheme S1: The recycling procedure of the complex 2A during the recoverable
2A-catalyzed hydrosilylation.
Author Contributions: N.L., J.-H.H., C.-R.S. performed the conceptualization and had the research
idea; E.T. and Y.L. performed syntheses and characterization of the platinum complexes, and con-
ducted the catalytic studies. E.T. and C.-F.C. studied the rate and mechanism of the catalytic reaction;

Molecules 2021, 26, 378
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N.L., C.-F.C. and C.-W.L. analyzed the obtained data and wrote the manuscript. All authors have
read and agreed to the published version of the manuscript.
Funding: MOST 106–2113-M-027–001 and university joint grants: NTUT-CGMH-108–03 and NTUT-
CGMH-106–7 (or CORPG3G0071).
Data Availability Statement: The data presented in this study are available in the article and
supplementary materials.
Acknowledgments: We gratefully acknowledge the Ministry of Science and Technology in Taiwan
and university joint grants (NTUT-CGMH). Authors thank R. L. Sobocinski for proof-reading.
Conflicts of Interest: The authors declare no conflict of interest.
Sample Availability: Some of fluorous platinum metal complexes are available from the authors.
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