bis-Nitrile and bis-Dialkylcyanamide Platinum(II) Complexes as Efficient Catalysts for Hydrosilylation Cross-Linking of Siloxane Polymers

Islamova, Regina M.; Dobrynin, Mikhail V.; Ivanov, Daniil M.; Власов, А. В.; Kaganova, E. V.; Grigoryan, G. V.; Kukushkin, Vadim Yu.

doi:10.3390/molecules21030311

Cited by 30 publications

(27 citation statements)

References 45 publications

(58 reference statements)

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“…In the process of polymerization, platinum may cause a release of hydrogen from water or hydroxyl groups, being the reason for emergence of bubbles in the plaster model [2]. The advantages of the addition silicon are: precise impression, minor contraction, detailed impression, high elasticity and quick restoration, dimensional stability, non-toxic and non-irritating.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dimensional Stability and Accuracy of Silicone – Based Impression Materials Using Different Impression Techniques – A Literature Review

Naumovski

Kapushevska

2017

Prilozi

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A quality-made dental impression is a prerequisite for successful fixed-prosthodontic fabrication and is directly dependent on the dimensional stability, accuracy and flexibility of the elastomeric impression materials, as well as on the appropriately used impression techniques. The purpose of this paper is to provide a literature review of relevant scientific papers which discuss the use of various silicone impression materials, different impression techniques and to evaluate their impact on the dimensional stability and accuracy of the obtained impressions. Scientific papers and studies were selected according to the materials used, the sample size, impression technique, storage time, type of measurements and use of spacer for the period between 2002 and 2016. In the reviewed literature several factors that influence the dimensional stability and accuracy of silicone impression molds, including the choice of the type of viscosity, impression material thickness, impression technique, retention of the impression material on the tray, storage time before the casting, number of castings, hydrophilicity of the material, release of byproducts, contraction after polymerization, thermal contraction and incomplete elastic recovery were presented. The literature review confirmed the lack of standardization of methodologies applied in the research and their great diversity. All findings point to the superiority of the addition silicone compared to the condensation silicone.

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Section: Introductionmentioning

confidence: 99%

“…The polycondensation process releases alcohol that contributes to the contraction (reduction) of the impression [2]. The advantages of the condensation silicon are: precise impression if poured quickly after it is taken and good elastic restoration after removing the impression from the mouth.…”

Section: Introductionmentioning

confidence: 99%

Dimensional Stability and Accuracy of Silicone – Based Impression Materials Using Different Impression Techniques – A Literature Review

Naumovski

Kapushevska

2017

Prilozi

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“…For example, Islamova et al. studied the activities of cis ‐ and trans ‐isomers of Pt II nitrile complexes ([PtCl 2 (NCR) 2 ], R=NMe 2 , N(C 5 H 10 ), Ph, CH 2 Ph, 18 ) for hydrosilylation cross‐linking . It was found that the cis ‐complexes are much more active than their trans ‐congeners and cis ‐[PtCl 2 (NCCH 2 Ph) 2 ] shows the best catalytic activity.…”

Section: Curing Systems (Cross‐linking Reactions)mentioning

confidence: 99%

Catalytic Systems for the Cross‐Linking of Organosilicon Polymers

Wang

Klein

Mejía

2017

Chemistry An Asian Journal

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Silicones and silicone rubbers are omnipresent in household and industrial products such as lubricants,c oatings, sealants,i nsulators, medicald evices, etc. This plethora of applicationsa rises from their unparalleled properties including hydrophobicity,l ow surfacee nergy,c hemical inertness, extreme temperature stability,e lasticity,a nd biocompatibility.E vent hough silicones have been known for more than five decades, their chemistry is still far from fully understood. Industrially,t he vast majority of processesf or their synthesis, transformation, andu se are based on rather well established, alas outdated technologies, which are frequently empirical and poorly investigated. Thisr eview attempts to summarize the different approaches for the synthesis of silicone rubbers by vulcanizationorc uring of silicone polymers, the catalysts used, and the corresponding reaction mechanisms. Apart from the well-known methods (radical, hydrosilylation, and metal-based condensation), novel approaches such as organo-and bio-catalysis are also addressed.

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“…[10] Pt(II) complexes were also studied as catalysts in hydrosilylation of styrene [11] and as improved alternative for curing of silicone rubber by hydrosilylation. [12] A neutral Pt(II) complex in its supramolecular assembly (microcrystalline fibbers) has been studied as a highly efficient polarized yellow-orange light emitter. [13] On the other hand, Pt(II) complexes are primarily known as widely used chemotherapy drugs, especially the complexes from the group of cisplatin [14] and related compounds with improved performance or less side effects.…”

Section: Introductionmentioning

confidence: 99%

Three Reactions, One Catalyst: A Multi‐Purpose Platinum(IV) Complex and its Silica‐Supported Homologue for Environmentally Friendly Processes

Racleş¹,

Zaltariov²,

Damoc³

et al. 2019

Applied Organom Chemis

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Although platinum nanoparticles and complexes ‐especially of Pt(0) and Pt(II)‐ are well known catalysts, siloxane‐based platinum complexes are rarely reported. Herein, a Platinum(IV) complex of 4‐aminopyridinium‐modified disiloxane was prepared and characterized by medium and far infrared spectroscopy, NMR and EDX. The formation of the complex was monitored by UV–Vis spectroscopy, which showed the high affinity and selectivity of this ligand for Pt, with a stability constant of 7.53·103 M−1. The catalytic activity of the siloxane‐based complex was tested in three types of reactions: reduction of p‐nitrophenol, oxidation of glucose and starch, and hydrosilylation. The hydrophobic behavior of the permethylated disiloxane moiety ensures good hydrolytic stability, while the N‐donor ligand stabilizes the in‐situ formed Pt nanoparticles. The generation of Pt nanoparticles during p‐nitrophenol reduction was confirmed by TEM and SEM. Contrary to most reports, the aerobic oxidation of mono‐ and polysaccharides occurred without oxidation agents or mediators added, in mild conditions, at room temperature and pH ~9. The same metal complex was found active in hydrosilylation of vinyl‐siloxanes with temperature‐modulated rate, thus being useful in silicone cross‐linking systems without the need of inhibitors. The method was adapted to one‐pot synthesis of silica‐supported Pt(IV) complex, which acted as efficient and reusable heterogeneous hydrosilylation catalyst, limiting the contamination of the product with Pt. This approach is promising for superior valorization of scarcely available and expensive platinum metal. By the same method, multifunctional soluble complexes and mesoporous silica may be obtained, with tunable catalytic performance.

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bis-Nitrile and bis-Dialkylcyanamide Platinum(II) Complexes as Efficient Catalysts for Hydrosilylation Cross-Linking of Siloxane Polymers

Cited by 30 publications

References 45 publications

Dimensional Stability and Accuracy of Silicone – Based Impression Materials Using Different Impression Techniques – A Literature Review

Dimensional Stability and Accuracy of Silicone – Based Impression Materials Using Different Impression Techniques – A Literature Review

Catalytic Systems for the Cross‐Linking of Organosilicon Polymers

Three Reactions, One Catalyst: A Multi‐Purpose Platinum(IV) Complex and its Silica‐Supported Homologue for Environmentally Friendly Processes

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