Mitsuo Ishikawa’s research while affiliated with Hiroshima University and other places

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Publications (302)


Platinum-catalyzed reactions of 2,3-bis(dimethylsilyl)pyridine with mono- and di-substituted alkynes
  • Article

March 2021

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18 Reads

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2 Citations

Inorganica Chimica Acta

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Shouta Yoshima

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Mitsuo Ishikawa

The synthesis and platinum-catalyzed reactions of 2,3-bis(dimethylsilyl)pyridine (1) are described. The reaction of 1 with diphenylacetylene in the presence of a platinum catalyst gave the corresponding six-membered ring compound arising from dehydrogenative double silylation of the alkyne. Similar reactions of 1 with mono-substituted acetylenes such as tert-butylacetylene, 1-hexyne, and phenylacetylene proceeded to give regioisomers of cyclic products.


Synthesis and optical properties of compounds via platinum-catalyzed hydrosilylation of triethynyltriazine and silyl-substituted oligothiophenes

April 2020

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12 Reads

Journal of Organometallic Chemistry

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Sakino Takase

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Haruka Komuro

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[...]

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Mitsuo Ishikawa

New types of starlike compounds and branched polymers with a triazine core and silylbithienyl or silylterthienyl arms were prepared by the use of platinum-catalyzed hydrosilylation. The UV–Vis absorption and fluorescence properties of these molecules have been investigated. In the fluorescence spectra of the silylbithienyl substituted starlike compound, their emission maxima derived from the bithiophene units were observed. In the branched polymer with silylbithienyl units, a peak derived from the interaction between the triazine and bithienyl units was observed at about 500 nm. No significant difference between the starlike compound and branched polymer with silylterthienyl units was observed in their UV–Vis absorption and fluorescence spectra. DFT calculations were performed to understand the photophysical properties of the starlike molecules with silylbithienyl and silylterthienyl arms.


Synthesis and optical properties of polymers with bithiophene condensed with disilacyclohexadiene rings and benzothiadiazole

September 2019

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18 Reads

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1 Citation

Journal of Organometallic Chemistry

New types of polymers composed of bithiophene condensed with disilacyclohexadiene rings and benzothiadiazole were prepared by the platinum-catalyzed dehydrogenative bissilylation. UV–Vis absorption and fluorescence properties of these polymers have been investigated. The fluorescence spectra of these polymers showed only the bands ascribed to the benzothiadiazole units even when the bithiophene units were irradiated. For these polymers, photoenergy transfer occurs from donor to acceptor. DFT calculations were performed to understand the photophysical properties of the polymers.


Platinum-catalyzed reactions of 3,4-bis(dimethylsilyl)- and 2,3,4,5-tetrakis(dimethylsilyl)thiophene with alkynes and alkenes

October 2018

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20 Reads

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9 Citations

Journal of Organometallic Chemistry

The reactions of 3,4-bis(dimethylsilyl)thiophene (1) and 2,3,4,5-tetrakis(dimethylsilyl)thiophene (17) with alkynes and alkenes have been reported. The reactions of 1 with alkynes such as diphenylacetylene, 3-hexyne, phenyltrimethylsilylacetylene, and trimethylsilylacetylene, in the presence of a catalytic amount of tetrakis(triphenylphosphine)platinum(0) at 80 °C gave the [1,4]disilino[2,3-c]thiophene derivatives. With alkenes under the same conditions, 1 afforded the five-membered ring products, in addition to hydrosilylation products. Treatment of 2,3,4,5-tetrakis(dimethylsilyl)thiophene (17) with diphenylacetylene and styrene gave the respective dehydrogenative double silylation products, arising from 2 equivalents of the alkyne and alkene, and compound 17.


Figure 1. Optimized structures for 10a, TS(10−11a), and 11a (left) and 10b, TS(10−11b), and 11b (right). Total energy of 10a is taken as the zero of relative energy. 
Figure 2. Optimized structures for TS(10−14a) and 14a (left), TS(10−14b) and 14b (right), and TS(14a−14b) (bottom center). Total energy of 10a is taken as the zero of relative energy. 
Figure 3. Energies for all optimized structures along the a-and b-reaction paths. Total energy of 10a is taken as the zero of relative energy. 
Figure 4 of 4
Platinum-Catalyzed Reactions of 2,3-Bis(diisopropylsilyl)thiophene with Alkynes
  • Article
  • Full-text available

November 2017

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75 Reads

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6 Citations

ACS Omega

The reactions of 2,3-bis(diisopropylsilyl)thiophene (1) with diphenylacetylene, phenylacetylene, trimethylsilylacetylene, and mesitylacetylene have been reported. The reactions of 1 with diphenylacetylene and phenylacetylene in the presence of a catalytic amount of tetrakis(triphenylphosphine)platinum(0) at 80 °C gave [1,4]disilino[2,3-b]thiophene derivatives. With trimethylsilylacetylene, 1 afforded two types of products arising from sp-hybridized C–H bond activation of the acetylene, together with [1,3]disilolo[4,5-b]thiophene derivatives. A similar treatment of 1 with mesitylacetylene produced two regioisomers of products arising from the C–H bond activation of mesitylacetylene. Theoretical calculations for the intramolecular reactions of 10a and 10b are also discussed.

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Platinum-catalyzed reactions of 2,3-bis(dimethylsilyl)furan with alkynes

October 2017

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23 Reads

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2 Citations

Journal of Organometallic Chemistry

The synthesis and platinum-catalyzed reactions of 2,3-bis(dimethylsilyl)furan (1) have been reported. The reactions of 1 with diphenylacetylene and phenyl(trimethylsilyl)acetylene in the presence of a platinum catalyst gave the corresponding six-membered ring compounds produced from dehydrogenative double silylation of alkynes. The similar reactions of 1 with mono-substituted acetylenes such as phenylacetylene and trimethylsilylacetylene proceeded to give the regioisomers of cyclic products. DFT calculations for the reaction mechanism of the platinum-catalyzed reaction of 1 with phenyl(trimethylsilyl)acetylene are also reported.


Preparation of branched molecules by regioselective hydrosilation of tetrakis(ethynyldimethylsilyl)silanes and some of their properties

July 2017

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15 Reads

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4 Citations

Journal of Organometallic Chemistry

New types of molecules, tetrasilylsilanes with the arms composed of oligothienylsilylvinyl units, were prepared by the platinum-catalyzed hydrosilation reactions. UV–Vis absorption and fluorescence properties of these molecules have been investigated. Polymer 9 showed good heat resistance against Td10 (10% weight loss temperature) at 402 °C even in air.


The Chemistry of Silacyclobutenes: Synthesis, Reactions, and Theoretical Studies

December 2016

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22 Reads

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8 Citations

Coordination Chemistry Reviews

The synthesis and reactions of various silacyclobutenes developed by our research group are reported in this review. The nickel-catalyzed reactions of phenylethynylpolysilanes and silacyclopropenes generated photochemically from the phenylethynylpolysilanes, with phenyl(silyl)acetylenes afforded the silacyclobutene derivatives. The photolysis and thermolysis of acylpolysilanes in the presence of alkynes readily produced the silacyclobutenes. These reactions provide important routes for the synthesis of various types of the silacyclobutenes. The silacyclobutenes thus obtained underwent thermal reactions to give many types of the products, whose structures highly depend on those of the starting silacyclobutenes. The results on the theoretical studies concerning the synthesis and reactions of the silacyclobutenes have also been reported.


Synthesis of pentamethyldisilanyl-substituted starlike molecule with triazine core and its application to dye-sensitized solar cells

October 2016

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5 Reads

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5 Citations

Journal of Organometallic Chemistry

Two-dimensional starlike molecule 7 consisting of benzothiadiazole-thiophenylphenyltriazine groups and pentamethyldisilanyl substituted thienylene units that extend to three directions was synthesized by the reactions of 2,4,6-tris[4-(4-hexyl-5-(7-(3-hexyl-5-iodothiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)-thiophen-2-yl)phenyl]-1,3,5-triazine (5) with the pentamethyldisilanylthienyl substituted stannyl derivative (6). UV-visible absorption and fluorescence properties of starlike molecules 4 and 7 have been investigated in dioxane and in the solid state. The application of TiO2-electrode coated on the surface with the use of 7 to dye-sensitized solar cells has been discussed.


Platinum-catalyzed reactions of 2,3-bis(diethylsilyl)thiophene with alkynes

September 2016

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21 Reads

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4 Citations

Journal of Organometallic Chemistry

The reactions of 2,3-bis(diethylsilyl)thiophene 1 with alkynes such as diphenylacetylene, 3-hexyne and phenylacetylene in the presence of a catalytic amount of Pt(PPh3)4 in benzene at 80 °C proceeded to give products 2, 3, and 6a,b, respectively. Treatment of a mixture consisting of 1 and 1,4-diethynylbenzene with a Pt(PPh3)4 catalyst in refluxing benzene produced three types of isomers consisting of two di(silyl)thiophene units and a diethynylbenzene unit. Computational analyses for the reaction mechanism of the platinum-catalyzed reaction have also been reported.


Citations (48)


... The reaction of 2,3-dibromopyridine with i-PrMgCl at room temperature followed by quenching with chloropentamethyldisilane afforded 2-bromo-3-(pentamethyldisilanyl)pyridine (1) in 70% yield. 25 To obtain 2-phenylethynyl-3-(pentamethyldisilanyl)pyridine, 1 was reacted with phenylacetylene under the Sonogashira coupling reaction conditions. When a mixture of 1 and ethynylbenzene in the presence of a PdCl 2 (PPh 3 ) 2 -CuI catalyst was heated to reflux in triethylamine, an unexpected product, 1,1-dimethyl-2-phenyl-3-(trimethylsilyl)-1H-silolo(3,2-b)pyridine (2a), was obtained in 15% isolated yield, along with intermolecular bis-silylation product 3a (8% yield) from the reaction of 2-phenylethynyl-3-(pentamethyldisilanyl)pyridine with phenylacetylene (Scheme 3). ...

Reference:

Synthesis of Pyridine-Fused Siloles by Palladium-Catalyzed Intramolecular Bis-Silylation
Platinum-catalyzed reactions of 2,3-bis(dimethylsilyl)pyridine with mono- and di-substituted alkynes
  • Citing Article
  • March 2021

Inorganica Chimica Acta

... Among the described alkyne hydrosilylation catalysts, those containing Pt, [9][10][11][12][13] Pd, [14] Rh,, [15][16][17] Ru, [18] etc. have been the most extensively studied. However, due to the low availability of noble metals and rising prices of such catalysts, more and more researchers try to develop sustainable alternatives. ...

Platinum-catalyzed reactions of 3,4-bis(dimethylsilyl)- and 2,3,4,5-tetrakis(dimethylsilyl)thiophene with alkynes and alkenes
  • Citing Article
  • October 2018

Journal of Organometallic Chemistry

... [29][30][31][32] A key step in the mechanism of transition metal-catalysed hydrosilylation is the oxidative addition of the metal to the Si-H bond. [21][22][23]25,26,[33][34][35] While this fundamental step of organometallic chemistry, to form (silyl)M(H) complexes, has been well-studied for Pd's neighbouring elements Rh, [36][37][38][39][40][41][42][43][44][45][46][47][48] Pt, [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] and most other transition metals, [33][34][35] it is much less understood for Pd. The oxidative addition of Rh and Pt to Si-H is facile, and complexes have been reported with a variety of ligand scaffolds and silanes. ...

Platinum-Catalyzed Reactions of 2,3-Bis(diisopropylsilyl)thiophene with Alkynes

ACS Omega

... 17 Computational details 18 Quantum chemical calculations were all performed at the density functional theory (DFT) level 19 using the Gaussian 16 software package 33 . The DFT functional used is the MN15 functional 20 34 . The models of CoPc, CoPc-16Cl, CoN4C10 motif (based on XANES spectra analysis, see 21 Supplementary Figs. ...

Preparation of branched molecules by regioselective hydrosilation of tetrakis(ethynyldimethylsilyl)silanes and some of their properties
  • Citing Article
  • July 2017

Journal of Organometallic Chemistry

... During the past two decades, intense interest has been directed towards silacyclobutenes due to their high ring strain and reactivity [1][2][3][4][5][6][7]. In particular, silacyclobut-2-ene has been the target of numerous investigations on its structure and reactivity since novel synthetic methods for silacyclobutene were developed by Auner [1] and Takahashi [2,3]. ...

The Chemistry of Silacyclobutenes: Synthesis, Reactions, and Theoretical Studies
  • Citing Article
  • December 2016

Coordination Chemistry Reviews

... These reactions can be performed using halogenated triazine derivatives (e.g., brominated triazine derivatives) [21] or triazine-based organometallics (e.g., triazine-based boronate esters) [46]. For example, 2,4,6-tris(4-(4,4,5,5tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl) [1,3,5] triazine is a joint starting compound to obtain large triazine-based structures by Suzuki couplings, as can be seen in Scheme 11A [53]. In addition, the implementation of a tribrominated triazine compound serves as an appropriate synthetic route to produce star-shaped photoactive molecules by C-N cross-coupling (also called Buchwald-Hartwig amination) or Stille reactions. ...

Synthesis of pentamethyldisilanyl-substituted starlike molecule with triazine core and its application to dye-sensitized solar cells
  • Citing Article
  • October 2016

Journal of Organometallic Chemistry

... 12,13 Recently, we have demonstrated that the platinum-catalyzed reactions of 2,3-bis(diethylsilyl)thiophene with alkynes such as diphenylacetylene, 3-hexyne, and phenylacetylene afford the respective [1,4]disilino [2,3-b]thiophenes. 14 In these reactions, [1,2,5]platinadisilolo [3,4-b]thiophene derivatives would be formed as the reactive intermediates. ...

Platinum-catalyzed reactions of 2,3-bis(diethylsilyl)thiophene with alkynes
  • Citing Article
  • September 2016

Journal of Organometallic Chemistry

... Although the BDE difference between the strain-free C-C and Si-C bonds is small, strain could be more important in the SCB ring than in the all-carbon cyclobutene ring (vide infra). Here it can be noted that the cyclobutene and disilacyclobut-3-ene rings are less suitable than the SCB ring because the former opens only rarely upon photolysis (e.g., benzocyclobutene does not undergo photochemical ring-opening unless further derivatized) [14,49], while the latter is unstable and readily oxidized in air to 1,3-disila-2-oxacyclopentenes [50]. It should also be noted that strained four-membered rings with heteroatoms from Groups 15 and 16 are problematic in the context of excited state aromaticity indicators as these heteroatoms provide lone-pair electrons that will interact electronically with the π-conjugated annulene. ...

The Chemistry of Benzodisilacyclobutenes and Benzobis(disilacyclobutene)s: New Development of Transition-Metal-Catalyzed Reactions, Stereochemistry and Theoretical Studies
  • Citing Article
  • January 2016

Dalton Transactions

... Cyclic organosilicon compounds have been intensively researched in the last decades as these heterocyclic systems find applications as odorants, pharmaceuticals, agrochemicals, dyes or polymers. [1][2][3][4][5][6][7] The smaller and thus strained silicon-containing heterocycles are also of fundamental interest due to their high reactivity. [8] Siletane, four-membered silacycles, were already discovered by Sommer and Baum in 1954 and prepared by reduction of chloro (3-bromopropyl)dimethylsilane. ...

The Chemistry of Silacyclopropenes
  • Citing Article
  • August 2015

... Since our initial study on the chemistry of benzo-1,1,2,2-tetraethyl-1, 2-disilacyclobutene published in 1991 [1], we have investigated the thermolysis, photolysis, and transition metal-catalyzed reactions of many benzo-1,2-disilacyclobutenes [2][3][4][5][6]. We have also found that the transition metal-catalyzed reactions of cis-and trans-benzo-1,2-ditert-butyl-1,2-dimethyl-and benzo-1,2-diisopropyl-1,2-dimethyl-1,2-disilacyclobutenes with alkynes proceeded with high stereospecificity to give the respective adducts, arising from the insertion of the carbon-carbon triple bond into a silicon-silicon bond in the benzodisilacyclobutenyl ring [7,8]. ...

Stereochemistry of Disilanylene-Containing Cyclic Compounds. Palladium-Catalyzed Reactions of cis- and trans-3,4-Benzo-1,2-diisopropyl-1,2-dimethyl-1,2-disilacyclobut-3-ene with Ethylene
  • Citing Article
  • May 2012

Organometallics