Wyniki wyszukiwania - BazTech

1

Kompleksy platyny typu Markó zawierające n-heterocykliczne ligandy karbenowe o właściwościach supersterycznych

Bolt Małgorzata, Żak Patrycja

Wiadomości Chemiczne

|

2021

|

[Z] 75, 1-2

31--53

EN

Progress in technology implying increasing demand for advanced materials dedicated for specific application has become a driving force stimulating research in different branches of science. It has been estimated that over 90% highly processed compounds have been obtained by the methods whose pivotal processes take place in the presence of catalysts based on transition metal complexes. Although these processes permit obtaining desired products, they are often charged with numerous drawbacks that prevent their implementation in industry. That is why the search for new catalytic systems ensuring high efficiency of final products and a possibility of reaction control is still an important direction of studies. Markó complexes are a group of platinum(0) coordination compounds of type [(NHC)Pt(dvtms)]. Although much attention has been recently attracted to these class of compounds, their number reported in hitherto literature is still limited. Owing to the possibility of wide modification of NHC carbene ligand attached to metal, the structures, and thus also properties, of the final complexes can be relatively easily matched to the requirements of individual catalytic reactions. It is particularly interesting in view of permanent development of new technologies and still increasing demand for new synthetic methods of more sophisticated materials dedicated to specific applications. In this paper, the synthesis and characterization of Markó type platinum(0) complexes containing bulky N-heterocyclic carbene ligands is described and their applications in the synthesis of new and unknown organic and organosilicon compounds are discussed. The main advantages of these complexes are highlighted providing an overview of this fascinating area of research.

2

Kataliza procesów hydrosililowania z udziałem cieczy jonowych

Bartlewicz Olga, Szymańska Anna, Jankowska-Wajda Magdalena, Dąbek Izabela, Maciejewski Hieronim

Wiadomości Chemiczne

|

2021

|

[Z] 75, 1-2

5--29

EN

Hydrosilylation is a fundamental and elegant method for the laboratory and industrial synthesis of organosilicon compounds. The hydrosilylation reaction is usually performed in a single-phase homogeneous system. A major problem, particularly in homogeneous catalysis, is the separation of catalyst from the reaction mixture. The presence of metals in the reaction products, even in trace quantities, is unacceptable for many applications, therefore efforts have been made at applying heterogeneous catalysts or immobilised metal complexes in order to obtain high catalytic activity and easy product isolation at the same time. One of the methods for producing such catalysts is the employment of ionic liquids as agents for the immobilization of metal complexes. Biphasic catalysis in a liquid-liquid system is an ideal approach through which to combine the advantages of both homogeneous and heterogeneous catalysis. The ionic liquids (ILs) generally form the phase in which the catalyst is dissolved and immobilized. In our research we have obtained a number of catalytic systems of such a type which were based on rhodium and platinum complexes dissolved in phosphonium, imidazolium, pyridinium and ammonium liquids. Currently, there has a common trend to obtain heterogenized systems that combine advantages of homogeneous and heterogeneous catalysis, which makes the hydrosilylation process more cost- effective. Such integration of homo- and heterogeneous catalysts is realized in several variants, as supported IL phase catalysts (SILPC) and solid catalysts with ILs layer (SCILL). Although all the above systems show high catalytic activities, their structure is unknown. This is why we have made attempts to modify selected ionic liquids (corresponding to our most effective systems) and we have applied them as ligands in the synthesis of platinum and rhodium complexes. Another group of catalysts comprises anionic complexes of rhodium and platinum which were obtained by reactions between halide complexes of metals and a respective ionic liquid. Most of the obtained complexes are solids insoluble in hydrosilylation reagents and are characterized by a high catalytic activity. A considerable development of heterogeneous catalysts of this type and their application in many hydrosilylation processes can be expected in the future. This mini-review briefly describes the recent progress in the design and development of catalysts based on the presence of ionic liquids and their applications for hydrosilylation processes.

3

Aminoalkyl functionalized siloxanes

Łubkowska M., Stańczyk W.

Polimery

|

2014

|

T. 59, nr 11-12

763--768

EN

Polydimethylsiloxanes bearing aminoalkyl groups as terminal or side chain moieties have found a broad application as polymer modifiers, fabric conditioners, release agents, personal care products and hydrophobizing agents. Methods of aminosiloxane synthesis as well as established and future applications of these silicone materials are reviewed.

PL

Przedstawiono metody syntezy funkcjonalizowanych silikonów — aminoalkilosiloksanów — polimerów i oligomerów o szerokim spektrum zastosowań w budownictwie, przemyśle włókienniczym i kosmetycznym. Opisano procesy kondensacji, hydrosililowania oraz polimeryzacji z otwarciem pierścienia, a także metody otrzymywania małocząsteczkowych siloksanów wykorzystywanych jako modyfikatory polimerów (poliamidów, poliuretanów i epoksydów). Omówiono również tradycyjne i potencjalne zastosowania tych amfifilowych materiałów.

4

Katalizowane cynkiem asymetryczne hydrosililowanie ketonów i imin

Gajewy J.

Wiadomości Chemiczne

|

2013

|

[Z] 67, 5-6

521--562

EN

One of the fundamental research goals in modern chemistry is the development of efficient and selective procedures to access organic compounds. Among all of the methodologies developed so far, catalysis offers an efficient and economical approach to enantiomericaly pure substances. In particular, transition metal catalysts modified by ligands, usually phosphines, are one of most successful examples of practical catalysis. Unfortunately, most of the applied metals (e.g., Pd, Rh, Ru, Ir) are low abundant, toxic and expensive. For this reason, recent research is focusing on their replacement by cheaper and low toxic metals. For example, the use of zinc can be of great interest, due to its abundance (0.0076% in the earth crust), biological relevance and distinct abilities. In the last two decades many scientific group have been working on finding new, high efficient and inexpensive catalytic system based on zinc for enantioselective transformations. It has been found that many of important organic reactions (for example aldol, Diels-Alder, Friedel-Crafts, Henry reactions) in their asymmetric version can be catalyzed by zinc complexes. One of them is also asymmetric reduction of double carbon-heteroatom bonds through addition of hydride (from silane). Hydrosilylation reduction is a promising alternative for the catalytic transformation of organic molecules to other reduction methods such as: hydrogenation and transfer hydrogenation owing to its operational simplicity and mild conditions. This review will give a general overview of the possible applications of zinc-catalyzed hydrosilylation of carbonyl compounds and imines. Since the understanding of mechanism of reaction is crucial for rational planning of new and more efficient ligands, some part of this article was devoted for mechanical considerations.

5

Synteza reaktywnych żywic siloksanowo-silseskwioksanowych

Szołyga M., Dutkiewicz M., Marciniec B., Maciejewski H.

Polimery

|

2013

|

T. 58, nr 10

766--771

PL

Na drodze kondensacji hydrolitycznej otrzymano serię żywic siloksanowo-silseskwioksanowych z węzłami sieci w postaci struktur POSS Q8, zawierających reaktywne grupy SiH obecne w mostkach siloksanowych łączących cząsteczki silseskwioksanu (POSS). Przebadano wpływ stechiometrii reagentów (POSS/dichlorometylosilan) na strukturę syntezowanego materiału. Przeprowadzono próby addycji grup SiH do wiązań wielokrotnych w olefinach, w reakcji hydrosililowania alkoholu allilowego. Otrzymano serię żywic zawierających w swojej strukturze reaktywne grupy funkcyjne, potencjalnie zdolne do oddziaływania z polimerami organicznymi, oraz jednostki Q8 POSS. Materiały tego typu mogą stanowić tańszą ale pełnowartościową alternatywę dla typowych POSS.

EN

A series of siloxane-silsesquioxane resins with POSS Q8 structures as network nodes containing reactive SiH groups in the siloxane bridges between silsesquioxane (POSS) molecules were prepared in a hydrolytic condensation process. The effect of reactant molar ratios (POSS/dichloromethylsilane) on the structure of synthesized product was investigated. Attempts were made to carry out the addition reaction of SiH groups with multiple bonds of olefins in the process of hydrosilylation of allyl alcohol. As a result, the resins containing Q8 POSS units and reactive functional groups capable to interact chemically with organic polymers, were obtained. This type of material can be a cheaper but still valuable alternative for the typical POSS compounds.

6

Efektywna synteza fluorofunkcyjnych (poli)siloksanów

Maciejewski H., Karasiewicz J., Marciniec B.

Polimery

|

2012

|

T. 57, nr 6

449-455

PL

Przeprowadzono badania nad syntezą fluorofunkcyjnych polisiloksanów opartą na procesach hydrosililowania fluorowanych eterów allilowych, których prekursorami były alkohole fluorowane. Porównano aktywność katalityczną kompleksów platyny i rodu w badanej reakcji i wyselekcjonowano najbardziej aktywny, bazujący na siloksylowym kompleksie rodu. Przeprowadzono także immobilizację wybranego kompleksu za pomocą czterech różnych cieczy jonowych i porównano aktywność katalityczną wytworzonych układów, w wielokrotnie powtórzonym cyklu reakcyjnym, przy użyciu takiej samej porcji katalizatora.

EN

Synthesis of fluorofunctional polysiloxanes based on hydrosilylation of fluoroalkyl ethers (precursors of the latter were fluoro alcohols) was studied. The most active catalyst, based on rhodium siloxide complex, was selected on the ground of a comparison of the catalytic performance of platinum and rhodium complexes. The rhodium complex was immobilized in four different ionic liquids and catalytic activities of the obtained systems were compared, while performing multiple reaction runs with the use of the same portion of catalyst.

7

Technologie syntezy fluorofunkcyjnych związków krzemu

Maciejewski H., Karasiewicz J.

Chemik

|

2012

|

Vol. 66, nr 7

735-741

PL

W artykule przedstawiono uniwersalną metodę syntezy dla różnorodnych fluorofunkcyjnych pochodnych krzemoorganicznych (silanów, polisiloksanów i silseskwioksanów) w oparciu o procesy hydrosililowania eterów allilowo-fluoroalkilowych, katalizowane siloksylowym kompleksem rodu [{Rh(?-OSiMe3)(cod)}2], im mobilizowanym w cieczy jonowej. Dla powyższego procesu przeprowadzono badania optymalizacyjne i określono podstawowe założenia technologiczne.

EN

A versatile method was presented for synthesis of different fluorofunctional organosilicon derivatives (silanes, polysiloxanes and silsesquioxanes) based on hydrosilylation of allyl-fluoroalkyl ethers. The process of hydrosilylation was catalysed by rhodium siloxide complex [{Rh-OSiMe3)(cod)}2] immobilised in ionic liquid. Studies on optimisation of the above process were performed and a brief foredesign was worked out.

8

Silicone nanostructures

Kępczyński M., Kuźmicz D., Romek M., Nowakowska M.

Polish Journal of Applied Chemistry

|

2009

|

Vol. 53, nr 1

37-42

EN

Polysiloxane with covalently attached undecanoic acid groups was obtained in a two-step synthesis. Four molecules of methyl undec-10-enoate were attached to 1,3,5,7-tetramethylcyclotetrasiloxane (D4H) by hydrosilylation reaction yielding a new monomer, tetra(l 1-methoxy-l l-oxoundecyl)tetramethyl-cyclotetrasiloxane . The monomer was polymerized using anionic ring opening polymerization with concomitant hydrolysis of ester bonds. The silicone polymer thus obtained can self-organize in aqueous environment forming large objects, probably vesicles, with diameter of 1 pm. Silicon nanocapsules of controlled size can be prepared in a simple way in the polymerization processes of Dj""1*"'1 within vesicle templates. The monomer swells the surfactant vesicles up to 50 mol % based on the surfactant. Polymerization of D4"IK,"yl inside membrane yields nanocapsules of size similar to the originate vesicles.

9

Liquid crystal monolayers on silicon surface

Szeląg A., Trybała A., Stańczyk W.

Polish Journal of Applied Chemistry

|

2009

|

Vol. 53, nr 1

93-99

EN

Surface Organometallic Chemistry (SOMC) methods have been applied, for the first time, in synthesis of liquid crystalline (LC) layers on silicon wafer surface. We have obtained unique materials with modified semiconductor (Si) surface, which can be applied in opto-electronics as switching and coupling devices as well as orienting optical elements in liquid crystalline cells. The covalently bonded LC monolayers can orient low molecular weight LC thin films up to -10 |im thickness. They are expected to be used primarily as a novel type of couplers and routers in laser telecommunication technology. The evaluation of the most effective analytical methods is also presented.

10

Technologie otrzymywania funkcjonalizowanych polisiloksanów

Maciejewski H., Szubert K., Marciniec B.

Polimery

|

2009

|

T. 54, nr 10

706-711

PL

Artykuł stanowi przegląd literaturowy dotyczący technologii otrzymywania sfunkcjonalizowanych polisiloksanów na drodze reakcji hydrosililowania katalizowanej kompleksem rodu [{Rh(ž-OSiMe3)(cod)}2] immobilizowanym w cieczy jonowej (schemat A). Przedstawiono założenia i parametry procesu (tabela 1), omówiono syntezę funkcjonalizowanych polisiloksanów na podstawie epoksyfunkcyjnych prekursorów siloksanowych a także wybrane zastosowania takich prekursorów do wytwarzania nowych materiałów.

EN

The paper is a review of technologies of preparation of polysiloxanes via hydrosilylation reaction catalyzed with rhodium complex [{Rh(ž-OSiMe3)(cod)}2] immobilized in ionic liquid (Scheme A). The assumptions and parameters of the process are presented (Table 1). The syntheses of functionalized polysiloxanes basing on epoxyfunctional silicone precursors were discussed as well as selected applications of such precursors for preparation of new materials.

11

Silikony "hybrydowe" - przegląd fluorowanych i niefluorowanych siloksanów polisilalkilenowych lub polisilarylenowych

Guida-Pietrasanta F.

Polimery

|

2006

|

T. 51, nr 2

104-114

PL

W artykule przeglądowym przedstawiono główne metody syntezy siloksanów polisilalkilenowych lub polisilarylenowych zwanych silikonami "hybrydowymi". Szczegółowo opisano dwie drogi syntezy: polikondensację zsyntetyzowanych a,w-bissilanoli (schematy A, C-P) i polihydrosililowanie a,w-dienów przez a,w-dihydrooligosiloksany (schematy B, Q-V). Omówiona nowa klasa polisiloksanów była zaprojektowana by zapobiegać depolimeryzacji, której ulegają klasyczne polisiloksany w średniej lub wysokiej temperaturze i w środowisku kwaśnym i zasadowym. Elastomery otrzymane w reakcji sieciowania tych nieorganiczno-organicznych polimerów hybrydowych charakteryzują się wysoką stabilnością termiczną pozwalającą na ich stosowanie w szerokim zakresie temperatur. Właściwy dobór łańcucha głównego i łańcuchów bocznych polimeru umożliwia uzyskanie materiałów o specyficznych właściwościach kwalifikujących je do używania w obszarze zaawansowanych technologii (kosmicznej, wojskowej, komputerowej, itp.).

EN

This overview on polysilalkylene or polysilarylene siloxanes fluorinated or not, so-called "hybrid" silicones reports the main synthetic routes to obtain these polymers together with the properties of the different polymers. Two routes are presented in more detail: - synthesis of a,w-bis silanol monomers (prepared either via an organometallic route or via hydrosilylation of a,w-dienes) followed by polycondensation of these bis silanols; - polyhydrosilylation of a,w-dienes by a,w-dihydrooligosiloxanes. This new class of polysiloxanes has been developed, mainly since the 1970s, to avoid the possible depolymerization observed under certain conditions (acid or base, medium or high temperature) for classical polysiloxanes. The elastomers prepared by crosslinking of these inorganic-organic hybrid polymers exhibit very high thermal stability and rather low temperature flexibility, and depending on the nature of their backbones or of their side chains, they may be resistant to solvents or fuels. They may thus find applications in advanced technological areas (aerospace, defense, computer applications).

12

Synthesis of Diphenylphosphine Oxide and Diethyl Phosphonate with 4-Dimethylsila-2-hexen-6-ol Moiety

Gawdzik B., Wawrzeńczyk C.

Polish Journal of Chemistry

|

2005

|

Vol. 79 / nr 3

541-545

EN

Two reagents useful for the Horner-Wittig or Wadshworth-Emmons reaction: 3-(2- hydroxyethyldimethylsila)-2-propen-1-yldiphenylphosphine oxide (5a) and diethyl 3-(2-hydroxyethyldimethylsila)-2-propen-1-ylphosphonate (5b) were synthesized from propargyl chloride and dimethylchlorosilane. The usefulness of phosphine oxide was demonstrated in the olefination reactions of benzaldehyde and hexanal.

13

Octasilsesquioxanes as Hybrid Nanocomposite Platforms. II. Synthesis, Characterization and Properties of Some Alkyl-functionalized Sislesquioxanes

Dare E., Olatunji G., Ogunniyi D.

Polish Journal of Chemistry

|

2005

|

Vol. 79 / nr 1

101-107

EN

The syntheses of octaalkylsilsesquioxanes 3, 4, 5 and 6 have been achieved by the platinum- catalyzed hydrosilylation of octahydrogensilsesquioxane 2 with _-halo-alkenes and other unsaturated substrates. These compounds were characterized by spectroscopic techniques and elemental analysis. Thermogravimetric analyses of 3 and 4 shows that they are reasonably stable thermally, and may act as building blocks to ceramics, nanometer ball bearing at around 400°C and photoresist materials.

14

Silanowe środki wiążące. Cz. IX. Epoksyfunkcyjne karbosilany

Maciejewski H., Dąbek I., Marciniec B.

Polimery

|

2004

|

T. 49, nr 10

677-683

PL

Epoksyfunkcyjne karbosilany stanowią kolejną grupę silanowych środków wiążących, które dzięki swojej budowie, a tym samym właściwościom, znajdują zastosowanie jako czynniki sieciujące, promotory adhezji oraz modyfikatory napełniaczy i powierzchni mineralnych. Przedstawiono metody syntezy, właściwości i charakterystykę, a także główne kierunki zastosowań epoksylunkcyjnych karbosilanów, w szczególności 3-glicydoksypropylotrialkoksysilanów i beta-(3,4-epoksycykloheksylo)etylotrialkoksysilanów. Pierwsze z tych związków są wykorzystywane przede wszystkim w roli silanowych środków wiążących, natomiast drugie jako modyfikatory polimerów. Opracowana przez autorów technologia syntezy 3-glicydoksypropylotrietoksysilanu, oparta na katalitycznym procesie hydrosililowania eteru allilowo-glicydylowego, stanowi podstawę produkcji tego silanu w P.I.W. Unisil w Tarnowie.

EN

Epoxyfunctional carbosilanes are a group of silane coupling agents, which because of their structures and properties are applied as crosslinking agents, adhesion promoters or modifiers of fillers and mineral surfaces. Methods of syntheses [equation (2) and (3)], properties and characteristics as well as main directions of applications of epoxyfunctional carbosilanes, especially 3-glicydoxypropyltrialkoxysilanes [Formula (I)] and beta-(3,4--epoxycyclohexyl)ethyltrialkoxysilanes [Formula (II)] have been presented. The first ones are used mainly as silane coupling agents while the other ones as modifiers of polymers. Technology, developed by authors, of 3-glicydoxypropyltriethoxysilane synthesis basing on catalytic process of allyl-glicydyl ether hydrosilylation is a base of this silane production at the UNISIL Co., Ltd. in Tarnów, Poland.

15

Hydrosililowanie organofunkcyjnych olein poli(wodoro, metylo) siloksanami

Maciejewski H., Guliński J., Marciniec B.

Przemysł Chemiczny

|

2003

|

T. 82, nr 8-9

918-920

16

Hydrosililowanie alkenów na katalizatorach multimetalicznych

Adamiec J., Fiedorow R., Charytonik J., Maciejewski H., Guliński J., Marciniec B.

Przemysł Chemiczny

|

2003

|

T. 82, nr 8-9

661-663

17

Synthesis of 3-chloropropyltrichlorosilane via the catalytic hydrosilylation of allyl chloride with trichlorosilane catalyzed by platinum catalyst - from laboratory scale to pilot plant

Guliński J., Marciniec B., Maciejewski H., Oczkowicz S.

Polish Journal of Chemical Technology

|

1999

|

Vol. 1, nr 1

11-15

EN

The method for the synthesis of 3-chloropropyltrichlorosilane based on the hydrosilylation of allyl chloride with trichlorosilane in the presence of an original Pt catalytic system has been worked out. The yield and selectivity of Cl(CH2)3SiCl3 depend on the nature of the catalytic system and several other factors (the mode of substrate addition, reaction procedure, etc.)- The optimum reaction conditions were determined. A successful scale-up of the process under study allowed us to implement it on a pilot scale as the first step of the newly emerging Polish low-tonnage organosilane industry.