Transition‐Metal‐Catalyzed Direct Arylation of Caged Silsesquioxanes: Substrate Scope and Mechanistic Study

Imoto, Hiroaki; Wada, Satoshi; Yumura, Takashi; Naka, Kensuke

doi:10.1002/ejic.201900126

Cited by 3 publications

(3 citation statements)

References 56 publications

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“…UV–vis spectroscopy revealed the typical absorption bands of aromatic groups connected to a silicon atom (see Figure S14 in the Supporting Information) . The absorption maxima for 1-NaphPhSi(OMe) 2 , 2-NaphPhSi(OMe) 2 , and 9-PhenPhSi(OMe) 2 were found at 284, 272, and 258 nm, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

2022

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High-refractive-index polysiloxanes containing naphthyl, phenanthrenyl, phenyl, and methyl groups have been synthesized using a polycondensation reaction starting from substituted di- and trialkoxysilanes. The obtained polymers comprised linear siloxane and partially cross-linked silsesquioxane units and showed optical transparencies of up to 99% at a thickness around 120 μm and high refractive indices of up to 1.622. The polymeric structures contained stabilized silanol groups that were further cross-linked at increased temperatures of 200 °C resulting in the formation of hybrid inorganic–organic resins. These typical thermal treatments at 200 °C for 72 h kept the transparencies as high as 98% and slightly lowered the RIs to values up to 1.610. A detailed structure evaluation of the resulting systems showed, depending on the size of the polycyclic aromatic substituent, excimer formation, which is based on weak interactions of the aromatic groups in the polymeric material. After thermal consolidation, glass-transition temperatures of the cross-linked systems were in the range of 18–74 °C depending on the composition. Thermal stabilities of the final resins reached higher values than commonly used siloxane resins up to 470 °C. The final materials are potential resins for high-temperature optical applications.

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Section: Results and Discussionmentioning

confidence: 99%

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

2022

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“…Selected examples to transform or derivatize POSS silanes include hydrolysis/alcoholysis, [24] arylation, [25, 26] and hydrosilylation [27, 28] (Figure 1 A). An ideal transformation for POSS functionalization would allow for one, three or eight reactions with minimal alteration of reaction setup up to gram‐scale.…”

Section: Figurementioning

confidence: 99%

Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium‐Catalyzed Carbene Insertion into Si−H Bonds

2021

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We report carbene insertion into Si−H bonds of polyhedral oligomeric silsesquioxanes (POSS) for the synthesis of highly functionalized siloxane nanomaterials. Dirhodium(II) carboxylates catalyze insertion of aryl‐diazoacetates as carbene precursors to afford POSS structures containing both ester and aryl groups as orthogonal functional handles for further derivatization of POSS materials. Four diverse and structurally varied silsesquioxane core scaffolds with one, three, or eight Si−H bonds were evaluated with diazo reactants to produce a total of 20 new POSS compounds. Novel diazo compounds containing a fluorinated octyl group and boron‐dipyrromethene (BODIPY) chromophore demonstrate the use of highly functionalized substrates. Transformations of aryl(ester)‐functionalized POSS compounds derived from this method are demonstrated, including ester hydrolysis and Suzuki–Miyaura cross‐coupling.

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“…Selected examples to transform or derivatize POSS silanes include hydrolysis/alcoholysis, [24] arylation, [25,26] and hydrosilylation [27,28] (Figure 1 A). An ideal transformation for POSS functionalization would allow for one, three or eight reactions with minimal alteration of reaction setup up to gram-scale.…”

mentioning

confidence: 99%

Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium‐Catalyzed Carbene Insertion into Si−H Bonds

2021

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We report carbene insertion into Si À H bonds of polyhedral oligomeric silsesquioxanes (POSS) for the synthesis of highly functionalized siloxane nanomaterials. Dirhodium(II) carboxylates catalyze insertion of aryl-diazoacetates as carbene precursors to afford POSS structures containing both ester and aryl groups as orthogonal functional handles for further derivatization of POSS materials. Four diverse and structurally varied silsesquioxane core scaffolds with one, three, or eight SiÀH bonds were evaluated with diazo reactants to produce a total of 20 new POSS compounds. Novel diazo compounds containing a fluorinated octyl group and boron-dipyrromethene (BODIPY) chromophore demonstrate the use of highly functionalized substrates. Transformations of aryl(ester)-functionalized POSS compounds derived from this method are demonstrated, including ester hydrolysis and Suzuki-Miyaura cross-coupling.

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Transition‐Metal‐Catalyzed Direct Arylation of Caged Silsesquioxanes: Substrate Scope and Mechanistic Study

Cited by 3 publications

References 56 publications

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium‐Catalyzed Carbene Insertion into Si−H Bonds

Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium‐Catalyzed Carbene Insertion into Si−H Bonds

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