A spectroscopic investigation of incompletely condensed polyhedral oligomeric silsesquioxanes (POSS-mono-ol, POSS-diol and POSS-triol): Hydrogen-bonded interaction and host–guest complex

Liu, Hongzhi; Kondo, Shin-ichi; Tanaka, Ryoji; Oku, Hirosuke; Unno, Masafumi

doi:10.1016/j.jorganchem.2008.01.027

Cited by 69 publications

(49 citation statements)

References 35 publications

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“…PSS are generally not able to model geminal silanols which might explain why 2 a – c did not show any signs of racemization in the silica‐mimicking experiments. Depending on concentration and solvent, PSS, furthermore, form dimers in solution lowering their acidity . In this regard, the use of silanetriols might be better suited to model the acidic surface of silica …”

Section: Methodsmentioning

confidence: 99%

Unusual Racemization of Tertiary P‐Chiral Ferrocenyl Phosphines

Popp

Hanf

Hey‐Hawkins

2020

Chemistry A European J

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Te rtiary phosphinesa re generally knownt o Scheme1.P-Stereogenic ferrocenyl phosphine boranes 1a-c. [a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.All given values are in kJ mol À1 .[a] See the Supporting Information for details. [b] DFT with ORCA: [37,38] PWPB95 [39] /def2-QZVP [40,41] . Figure 3. Calculated [37][38][39][40][41] structure of 2a.U pon protonation the internal dihedral angle (PCCC) is significantly decreased. Hydrogena toms, except for phosphorus-bound proton,a nd 4-methoxyphenyl groups are omitted for clarity.

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Section: Methodsmentioning

confidence: 99%

Unusual Racemization of Tertiary P‐Chiral Ferrocenyl Phosphines

Popp

Hanf

Hey‐Hawkins

2020

Chemistry A European J

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“…The intramolecular and intermolecular hydrogen-bondingi nteractions for POSS-silanol have been investigated. [26][27][28] Compared with POSS-diols, which only participate in intramolecular H-bonding,P OSS-triols form intermoleculars elf-associated species( in both solution phase and solid phase). However,n ow ork has commented on concentration effects of POSS-related silanol H-bondingw ith an emphasis on the inhibition or enhancement on catalytic activity.P revious work to study model-like catalysis of POSS-triols has focused on metal-siloxide coordination; [16,29,30] no literature describes the mechanisticb ehavior of POSS-triols as catalysts in the absence of metals.I nt hese studies,t he observed catalytic activity was hypothesized to effectively mimic what occurs on asilica surface.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and Binding Studies Reveal Cooperativity and Off‐Cycle Competition for H‐Bonding Catalysis with Silsesquioxane Silanols

Jagannathan

Diemoz

Targos

et al. 2019

Chemistry A European J

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The catalytic activity, kinetics, and quantification of H‐bonding ability of incompletely condensed polyhedral oligomeric silsesquioxane (POSS) silanols are reported. POSS‐triols, a homogeneous model for vicinal silica surface sites, exhibit enhanced H‐bonding compared with other silanols and alcohols as quantified using a 31P NMR probe. Evaluation of a Friedel–Crafts addition reaction shows that phenyl‐POSS‐triol is active as an H‐bond donor catalyst whereas other POSS silanols studied are not. An in‐depth kinetic study (using RPKA and VTNA) highlights the concentration‐dependent H‐bonding behavior of POSS‐triols, which is attributed to intermolecular association forming an off‐cycle dimeric species. Binding constants provide additional support for reduced H‐bond ability at higher concentrations, which is attributed to competitive association. POSS‐triol self‐association disrupts H‐bond donor abilities relevant for catalysis by reducing the concentration of active monomeric catalyst.

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“…They have attracted considerable interest in recent years due to not only their high performance, which originates from the combination of advantages of the inorganic and organic components in these materials, but also the unique features derived from their nanometer‐scale architecture 6–10. POSS have proven to be excellent platforms for new hybrid materials,11–14 homogeneous models for silica,15, 16 supports for organometallic catalysts,17–19 biocompatible drug carriers,20 and also as anion receptors 21, 22…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, and thermal curing of a novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane

Fan

Yang

2012

J of Applied Polymer Sci

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A novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane (OPAPS, (SiO 1.5 C 6 H 4 NHCH 2 CBCH) 8 ) was prepared from octa(aminophenyl)silsesquioxane and propargyl bromide. The chemical structure of OPAPS was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance, X-ray diffraction (XRD), high-performance liquid chromatography, gel permeation chromatography, differential scanning calorimetry, and thermal gravimetric analysis (TGA). The structure of the thermally cured polymer of OPAPS was characterized by FTIR, XRD, and TGA. It had good thermal stability. TGA demonstrated that the thermal decomposition temperatures (T d5 ) of the cured OPAPS polymer in nitrogen and air were 455.6 and 458.8 C, respectively. The thermal curing reaction kinetics of OPAPS were studied and some kinetic parameters were obtained.

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A spectroscopic investigation of incompletely condensed polyhedral oligomeric silsesquioxanes (POSS-mono-ol, POSS-diol and POSS-triol): Hydrogen-bonded interaction and host–guest complex

Cited by 69 publications

References 35 publications

Unusual Racemization of Tertiary P‐Chiral Ferrocenyl Phosphines

Unusual Racemization of Tertiary P‐Chiral Ferrocenyl Phosphines

Kinetic and Binding Studies Reveal Cooperativity and Off‐Cycle Competition for H‐Bonding Catalysis with Silsesquioxane Silanols

Synthesis, characterization, and thermal curing of a novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane

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