scholarly journals Preparation of Tri(alkenyl)functional Open-Cage Silsesquioxanes as Specific Polymer Modifiers

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1063
Author(s):  
Katarzyna Mituła ◽  
Michał Dutkiewicz ◽  
Julia Duszczak ◽  
Monika Rzonsowska ◽  
Beata Dudziec
Keyword(s):  
Condensation Reaction ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Double Decker ◽  
Application Potential ◽  
Synthetic Routes ◽  
High Yields ◽  
Chain Lengths ◽  
Tga And Dsc ◽  
Melting And Crystallization Temperatures

The scientific reports on polyhedral oligomeric silsesquioxanes are mostly focused on the formation of completely condensed T8 cubic type structures and recently so-called double-decker derivatives. Herein, we report on efficient synthetic routes leading to trifunctionalized, open-cage silsesquioxanes with alkenyl groups of varying chain lengths from -vinyl to -dec-9-enyl and two types of inert groups (iBu, Ph) at the silsesquioxane core. The presented methodology was focused on hydrolytic condensation reaction and it enabled obtaining titled compounds with high yields and purity. A parallel synthetic methodology that was based on the hydrosilylation reaction was also studied. Additionally, a thorough characterization of the obtained compounds was performed, also in terms of their thermal stability, melting and crystallization temperatures (TGA and DSC) in order to show the changes in the abovementioned parameters dependent on the type of reactive as well as inert groups at Si-O-Si core. The presence of unsaturated alkenyl groups has a profound impact on the application potential of these systems, i.e., as modifiers or comonomers for copolymerization reaction.

scholarly journals Synthetic Routes to Silsesquioxane-Based Systems as Photoactive Materials and Their Precursors

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 504 ◽  
Author(s):  
Beata Dudziec ◽  
Patrycja Żak ◽  
Bogdan Marciniec
Keyword(s):  
Scientific Literature ◽  
Complex Nature ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Optoelectronic Materials ◽  
Organic Chromophores ◽  
The Past ◽  
Photoactive Materials ◽  
Application Potential ◽  
Synthetic Routes ◽  
Organic Optoelectronic

Over the past two decades, organic optoelectronic materials have been considered very promising. The attractiveness of this group of compounds, regardless of their undisputable application potential, lies in the possibility of their use in the construction of organic–inorganic hybrid materials. This class of frameworks also considers nanostructural polyhedral oligomeric silsesquioxanes (POSSs) with “organic coronae” and precisely defined organic architectures between dispersed rigid silica cores. A significant number of papers on the design and development of POSS-based organic optoelectronic as well as photoluminescent (PL) materials have been published recently. In view of the scientific literature abounding with numerous examples of their application (i.e., as OLEDs), the aim of this review is to present efficient synthetic pathways leading to the formation of nanocomposite materials based on silsesquioxane systems that contain organic chromophores of complex nature. A summary of stoichiometric and predominantly catalytic methods for these silsesquioxane-based systems to be applied in the construction of photoactive materials or their precursors is given.

Improved Elastomers through Control of Network Chain-Length Distributions

1999 ◽  
Vol 72 (3) ◽  
pp. 465-483 ◽  
Author(s):  
J. E. Mark
Keyword(s):  
Chain Length ◽  
Addition Reaction ◽  
Condensation Reaction ◽  
Bimodal Distribution ◽  
Polymer Chains ◽  
Network Chain ◽  
End Linking ◽  
Chain Lengths ◽  
Bimodal Elastomers

Abstract Methods are described for obtaining elastomers of controlled network chain-length distributions by restricting the reactivity of the polymer chains to their ends, and then end linking these chains with a multi-functional reactant. The networks of this type that have proved to be of greatest interest consist of short chains end linked with long chains to yield a bimodal distribution of network chain lengths. These bimodal elastomers have unusually high extensibility for their values of the modulus and ultimate strength, and thus considerable toughness, even in the unfilled state. Most such elastomers have been prepared from chains of poly(dimethylsiloxane), by carrying out either a condensation reaction between hydroxyl-terminated chains and tetraethoxysilane, or an addition reaction between vinyl-terminated chains and a poly(methylhydrogen siloxane) oligomer. The material presented in this review discusses the preparation of such elastomers, the characterization of some of their properties, and the interpretation of some of these properties in terms of the molecular theories of rubber-like elasticity.

Synthetic Routes for 1,4-disubstituted 1,2,3-triazoles: A Review

2019 ◽  
Vol 23 (8) ◽  
pp. 860-900 ◽  
Author(s):  
Chander P. Kaushik ◽  
Jyoti Sangwan ◽  
Raj Luxmi ◽  
Krishan Kumar ◽  
Ashima Pahwa
Keyword(s):  
Solid Phase ◽  
Click Reaction ◽  
Biological Activities ◽  
Triazole Ring ◽  
Copper Catalysts ◽  
Biologically Active ◽  
Pharmaceutical Chemistry ◽  
Biological Targets ◽  
Synthetic Routes ◽  
High Yields

N-Heterocyclic compounds like 1,2,3-triazoles serve as a key scaffolds among organic compounds having diverse applications in the field of drug discovery, bioconjugation, material science, liquid crystals, pharmaceutical chemistry and solid phase organic synthesis. Various drugs containing 1,2,3-triazole ring which are commonly available in market includes Rufinamide, Cefatrizine, Tazobactam etc., Stability to acidic/basic hydrolysis along with significant dipole moment support triazole moiety for appreciable participation in hydrogen bonding and dipole-dipole interactions with biological targets. Huisgen 1,3-dipolar azide-alkyne cycloaddition culminate into a mixture of 1,4 and 1,5- disubstituted 1,2,3-triazoles. In 2001, Sharpless and Meldal came across with a copper(I) catalyzed regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles by cycloaddition between azides and terminal alkynes. This azide-alkyne cycloaddition has been labelled as a one of the important key click reaction. Click synthesis describes chemical reactions that are simple to perform, gives high selectivity, wide in scope, fast reaction rate and high yields. Click reactions are not single specific reaction, but serve as a pathway for construction of simple to complex molecules from a variety of starting materials. In the last few decades, 1,2,3-triazoles attracted attention of researchers all over the world because of their broad spectrum of biological activities. Keeping in view the biological importance of 1,2,3-triazole, in this review we focus on the various synthetic routes for the syntheisis of 1,4-disubstituted 1,2,3-triazoles. This review involves various synthetic protocols which involves copper and non-copper catalysts, different solvents as well as substrates. It will boost synthetic chemists to explore new pathway for the development of newer biologically active 1,2,3-triazoles.

Synthesis of 3-(Cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8- carboxylic Acids Via an Efficient Three-component Condensation Reaction between Cyclohexylisocyanide and 2-Aminopyridine-3-carboxylic Acid in the Presence of Aromatic Aldehyde

2018 ◽  
Vol 21 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ghasem Marandi
Keyword(s):  
Biological Sciences ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
High Performance ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
New Materials ◽  
One Pot ◽  
High Yields ◽  
Benzaldehyde Derivatives

Aim and Objective: The reaction of cyclohexylisocyanide and 2-aminopyridine-3- carboxylic acid in the presence of benzaldehyde derivatives in ethanol led to 3-(cyclohexylamino)-2- arylimidazo[1,2-a]pyridine-8-carboxylic acids in high yields. In a three component condensation reaction, isocyanide reacts with 2-aminopyridine-3-carboxylic acid and aromatic aldehydes without any prior activation. Material and Methods: The synthesized products have stable structures which have been characterized by IR, 1H, 13C and Mass spectroscopy as well as CHN-O analysis. Results: In continuation of our attempts to develop simple one-pot routes for the synthesis of 3- (cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids, aromatic aldehydes with divers substituted show a high performance. Conclusion: In conclusion, this study introduces the art of combinatorial chemistry using a simple one-pot procedure for the synthesis of new materials which are interesting compounds in medicinal and biological sciences.

Synthesis and Characterization of a Novel Ionic Liquid Based on N,N,N,N-tetramethylethylenediamine and its Application in the Synthesis of 1,8-dioxo-octahydro Xanthenes

2018 ◽  
Vol 21 (7) ◽  
pp. 526-532 ◽  
Author(s):  
Zahra Abdi Piralghar ◽  
Mohammad Mahmoodi Hashemi ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Chlorosulfonic Acid ◽  
Solvent Free ◽  
Aryl Aldehydes ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Solvent Free Conditions ◽  
Aryl Aldehyde ◽  
High Yields

Aim and Objective: In this work, we synthesized and characterized a novel Brönsted acidic ionic liquid from the reaction of N, N, N’, N’-tetramethylethylenediamine with chlorosulfonic acid and explored its catalytic activity in 1, 8-dioxo-octahydroxanthenes synthesis. Materials and Methods: Dimedone, aryl aldehydes, and the ionic liquid as the catalyst were reacted under solvent-free conditions. The progressive of the reaction was monitored by a thin layer of chromatography (ethyl acetate/n-hexane = 1/5). All products were characterized as the basis of their spectra data and melting point by comparison with those reported in the literature. Results: The prepared ionic liquid was successfully applied in the synthesis of 1, 8-dioxooctahydroxanthenes in good to high yields on the reaction of aryl aldehyde and dimedone at 120oC under solvent-free conditions. Conclusion: This research demonstrates that the catalyst is impressive for 1, 8-dioxo-octahydroxanthenes synthesis under solvent-free conditions.

Temperature Dependent Green Synthesis of 3-Carboxycoumarins and 3,4-unsubstituted Coumarins

2019 ◽  
Vol 16 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Jack van Schijndel ◽  
Dennis Molendijk ◽  
Luiz Alberto Canalle ◽  
Erik Theodorus Rump ◽  
Jan Meuldijk
Keyword(s):  
Knoevenagel Condensation ◽  
Ammonium Bicarbonate ◽  
Solvent Free ◽  
Temperature Dependent ◽  
Step Procedure ◽  
Synthetic Routes ◽  
High Yields ◽  
Temperature Optima ◽  
Solvent Free Synthesis ◽  
Full Conversion

Aim and Objective: Because of the low abundance of 3,4-unsubstituted coumarins in plants combined with the complex purification process required, synthetic routes towards 3,4-unsubstituted coumarins are especially valuable. In the present work, we explore the possibilities of a solvent-free Green Knoevenagel condensation on various 2-hydroxybenzaldehyde derivatives and malonic acid without the use of toxic organocatalysts like pyridine and piperidine but only use ammonium bicarbonate as the catalyst. Materials and Methods: To investigate the scope of the Green Knoevenagel condensation for the synthesis of 3,4-unsubstituted coumarins, various 2-hydroxybenzaldehyde derivatives were screened as starting material in the optimized two-step procedure developed for 2-hydroxybenzaldehyde. </P><P> Results: This study shows that the intramolecular esterification and the decarboxylation are in competition, but show different temperature optima. In order to suppress premature decarboxylation and maximize the yield of coumarin, a two-step procedure was adopted. The reaction mixture containing ammonium bicarbonate is initially kept at 90ºC for 1 hour. After completion of the cyclization, the temperature of the reaction mixture is increased to 140ºC for 2 hours. Following this protocol, coumarin could be isolated with a yield of 95%. Conclusion: A two-step procedure for the solvent-free synthesis of several 3,4-unsubstituted coumarins was developed using ammonium bicarbonate, resulting in high yields of the desired products. Moreover, this procedure has a low E-factor and is, therefore an environmental friendly reaction in line with the principles of Green Chemistry. It was shown that by initially capping the temperature at 90ºC, premature decarboxylation can be suppressed. After full conversion to the intermediate 3-carboxycoumarin, the temperature can be increased to 140ºC finalizing the reaction. Ammonium bicarbonate was shown to catalyze both the Green Knoevenagel condensation and the decarboxylation step.

scholarly journals Steady state charge conduction through solution processed liquid crystalline lanthanide bisphthalocyanine films

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1603-1615
Author(s):  
Chandana Pal ◽  
Isabelle Chambrier ◽  
Andrew N. Cammidge ◽  
A. K. Sharma ◽  
Asim K. Ray
Keyword(s):  
Metal Ions ◽  
Liquid Crystalline ◽  
Microscopy Study ◽  
Individual Characteristics ◽  
Central Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Double Decker ◽  
Order Of Magnitude ◽  
Chain Lengths

In-plane electrical characteristics of non-peripherally octyl(C[Formula: see text]H[Formula: see text]- and hexyl(C[Formula: see text]H[Formula: see text]-substituted liquid crystalline (LC) double decker lanthanide bisphthalocyanine (LnPc[Formula: see text] complexes with central metal ions lutetium (Lu), and gadolinium (Gd) have been measured in thin film formulations on interdigitated gold (Au) electrodes for the applied voltage ([Formula: see text] range of [Formula: see text]. The conduction mechanism is found to be Ohmic within the bias of [Formula: see text] while the bulk limited Poole–Frenkel mechanism is responsible for the higher bias. The compounds show individual characteristics depending on the central metal ions, substituent chain lengths and their mesophases. Values of 67.55 [Formula: see text]cm[Formula: see text] and 42.31 [Formula: see text]cm[Formula: see text] have been obtained for room temperature in-plane Ohmic conductivity of as-deposited octyl lutetium (C[Formula: see text]LuPc[Formula: see text] and hexyl gadolinium (C[Formula: see text]GdPc[Formula: see text] films, respectively while C[Formula: see text]GdPc[Formula: see text] films exhibit nearly two orders of magnitude smaller conductivity. On annealing at 80[Formula: see text]C, Ohmic conductivities of C[Formula: see text]LuPc[Formula: see text] and C[Formula: see text]GdPc[Formula: see text] are found to have increased but the conductivity of C[Formula: see text]GdPc[Formula: see text] decreased by more than one order of magnitude to 1.5 [Formula: see text]cm[Formula: see text]. For physical interpretation of the charge transport behavior of these three molecules, their UV-vis optical absorption spectra in the solution and in as-deposited and annealed solid phases and atomic force microscopy study have been performed. It is believed that both orientation and positional reorganizations are responsible, depending upon the size of the central ion and side chain length.

scholarly journals Synthesis of Silsesquioxanes with Substituted Triazole Ring Functionalities and Their Coordination Ability

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 439
Author(s):  
Monika Rzonsowska ◽  
Katarzyna Kozakiewicz ◽  
Katarzyna Mituła ◽  
Julia Duszczak ◽  
Maciej Kubicki ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Molecular Complex ◽  
Coordination Compounds ◽  
Triazole Ring ◽  
Spectroscopic Characterization ◽  
Process Conditions ◽  
Double Decker ◽  
Triazole Ligand ◽  
Coordination Ability ◽  
High Yields

A synthesis of a series of mono-T8 and difunctionalized double-decker silsesquioxanes bearing substituted triazole ring(s) has been reported within this work. The catalytic protocol for their formation is based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) process. Diverse alkynes were in the scope of our interest—i.e., aryl, hetaryl, alkyl, silyl, or germyl—and the latter was shown to be the first example of terminal germane alkyne which is reactive in the applied process’ conditions. From the pallet of 15 compounds, three of them with pyridine-triazole and thiophenyl-triazole moiety attached to T8 or DDSQ core were verified in terms of their coordinating properties towards selected transition metals, i.e., Pd(II), Pt(II), and Rh(I). The studies resulted in the formation of four SQs based coordination compounds that were obtained in high yields up to 93% and their thorough spectroscopic characterization is presented. To our knowledge, this is the first example of the DDSQ-based molecular complex possessing bidentate pyridine-triazole ligand binding two Pd(II) ions.

scholarly journals Rapid four-component synthesis of dihydropyrano[2,3-c]pyrazoles using nano-eggshell/Ti(IV) as a highly compatible natural based catalyst

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Reaction Times ◽  
Diffraction Field ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Work Up

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.

Synthesis and characterization of periphery-functionalized porphyrazines containing mixed pyrrolyl and pyridylmethylamino groups

2009 ◽  
Vol 13 (02) ◽  
pp. 223-234 ◽  
Author(s):  
Tomasz Goslinski ◽  
Ewa Tykarska ◽  
Wojciech Szczolko ◽  
Tomasz Osmalek ◽  
Aleksandra Smigielska ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Chemical Sensors ◽  
Electronic Materials ◽  
Condensation Reaction ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Coordination Properties ◽  
Perpendicular Orientation ◽  
Selective Sensor

The condensation reaction of 2-amino-3-[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile with a series of diketones led to novel dinitriles, of which 2-(2,5-dimethyl-1H-pyrrol-1-yl)-3-[methyl(3-pyridylmethylene)amino]-2(Z)-butene-1,4-dinitrile, the product of the Paal-Knorr reaction, was successfully utilized in the Linstead macrocyclization towards symmetrical and unsymmetrical porphyrazines. NMR and X-ray study revealed an almost perpendicular orientation of the pyrrolyl groups in relation to the porphyrazine platform. The newly synthesized macrocycles with different peripheral groups show interesting spectroscopic and electrochemical properties. Due to selective sensor/coordination properties they are expected to find applications as chemical sensors and electronic materials.

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