Styrenyl Groups Research Articles

Mechanofluorochromic property of coumarin derivatives containing carbonyl group

Four novel coumarin derivatives with different substituents (CMCO-H, CMCO-F, CMCO-CH3 and CMCO-CF3) functionalized by carbonyl unit were designed and synthesized. The relationship between spatial structure and photophysical properties of these coumarin compounds in different states had been systematically studied. In the single molecule state, with the increase of solvent polarities, the fluorescent peaks exhibited obvious solvatochromic effect, accompanied by a decrease in intensity. The significant solvatochromism effect suggested that these four coumarin derivatives both are typical intramolecular charge transfer molecules. The density functional theory calculation results showed that the electron clouds were transferred from coumarin unit and the connected aromatic ring to carbonyl and styrenyl groups. Meanwhile, compounds CMCO-CH3 and CMCO-CF3 exhibited reversible mechanofluorochromic (MFC) property between yellow and orange emission. The single crystal XRD, powder XRD and SEM experiment suggested that the modulation of photophysical properties come from the change of compounds spatial structures. The study provided an efficient way for the design of organic compounds with MFC property.

Synthesis of Oxazolones with Extended Conjugation and Evaluation of their Linear and Nonlinear Optical Photochemistry

AbstractOxazolones or azlactones are small heterocyclic systems that can be easily functionalized with a double bond directly attached to their structure. In addition, they can be substituted on the opposite side of the heterocycle with styrenyl groups to extend their conjugation. This allows for versatile tuning of their linear and non‐linear optical properties. In this work, eight doubly substituted oxazolones including different push‐pull or pull‐pull designs were synthesized, and their linear and non‐linear photophysical properties were studied. As we show, the two‐photon activity of these systems is dependent on the donor‐acceptor pattern, where a methoxy substitution on the styrene end of the molecule and an acetyl group on the other end shows two‐photon Z‐E conversion properties with an important two photon absorption cross section of 308 GM. Most oxazolones shown in this study undergo picosecond relaxation to the electronic ground state, releasing the biphotonic energy to their surrounding environment. The results obtained in this work are indicative of potential applications of these molecules in schemes where high spatial patterning or thermalization is required.

Polymerizable Surfactant Ligand for Stabilization and Film Formation of CsPbBr3 Nanocrystals.

Surfactant ligands are important in the synthesis of inorganic perovskite nanocrystals (NCs), not only for stabilizing NCs but also for surface defect passivation. A new polymerizable surfactant ligand with a multidentate l-cysteine head, a long oleoyl tail, and a polymerizable styrenyl group (NOSVC) is designed for the post-synthesis treatment and stabilization of colloidal CsPbBr3 NCs in this work. 1H nuclear magnetic resonance and X-ray photoelectron spectroscopy analysis show that the l-cysteine head has strong interactions with the NCs. The absolute photoluminescence quantum yields of the colloidal NCs are increased from 45.1% of the pristine NCs stabilized with oleic acid/oleyl amine to 91.8% after NOSVC treatment. NOSVC-stabilized CsPbBr3 colloidal NCs show enhanced stabilities when exposed in polar solvents. The NOSVC-stabilized CsPbBr3 NCs in a solid film state allow for a photopolymerization to be carried out with the assistance of a photoinitiator. The polymerized films of NOSVC-treated NCs exhibit significantly enhanced stability against thermal radiation, ultraviolet irradiation, and humidity. We also fabricated self-healing polymer films incorporating NOSVC-treated CsPbBr3 NCs as a green filter for a white light-emitting diode device. The green light-emitting films are very stable in humid environments, revealing the great application potential of NOSVC-treated CsPbBr3 NCs in flexible display and lighting devices.

Tuning Mechanical Properties of Polymeric Hydrogels Using Orthogonally Functionalized Crosslinkers

A unique orthogonal crosslinker-induced hydrogel, whose mechanical strength can be tunable by the crosslinker topology upon thermal treatment, is described herein. The crosslinker containing cationic moieties and crosslinkable styrenyl groups was employed for the preparation of orthogonally crosslinked hydrogels having ionic and covalent characteristics. The manipulation of the orthogonal crosslinkers topology and the ionic bond strength between cationic and anionic moieties facilitated the control of the mechanical properties. Short-term temporal modulation of hydrogel moduli, a key factor of the substrates for cell development, was demonstrated and could provide dynamic microenvironment for biological process. In addition, on-demand control of the elastic properties of the hydrogels by application of a thermal stimulus provides new avenues to regulate cell growth. Furthermore, the orthogonality of the crosslinkers allowed molecular functionalization of a wide range of molecules of interest to the hydrogels by thiol-ene Michael addition (nucleophilic addition of sulfhydryl and carbon-carbon double bonds) in a friendly manner as demonstrated in our work.

Straightforward Synthesis of Triester-Substituted Pyrrolizidines by a Three-Component Reaction of β,γ-Unsaturated α-Keto Esters, Proline, and Maleates

A three-component reaction of β,γ-unsaturated α-keto esters, proline, and dialkyl maleates has been developed. This reaction provides pyrrolizidine derivatives containing three ester groups and a styrenyl group, as well as a quaternary center, in moderate to good yields and with good to excellent diastereoselectivities.

One-pot regioselective synthesis of meta-terphenyls via [3 + 3] annulation of nitroallylic acetates with alkylidenemalononitriles.

A highly efficient one-pot method has been developed for the synthesis of meta-terphenyls via a regioselective [3 + 3] annulation-elimination sequence involving Morita-Baylis-Hillman (MBH) acetates of nitroalkenes and alkylidenemalononitriles. The reaction takes place in a regioselective manner under mild conditions (Et3N, room temperature) to afford a wide variety of meta-terphenyls bearing aryl, heteroaryl and styrenyl groups. This novel [3 + 3] annulation takes advantage of the 1,3-bielectrophilic character of MBH acetates and 1,3-binucleophilic character of alkylidenemalononitriles and proceeds in a cascade fashion comprising an SN2' substitution, intramolecular 6-endo-trig Michael addition and double elimination. Representative synthetic transformations of the products, for instance, to meta-terphenyl derived isoindolinones have also been demonstrated.

Total Synthesis of (−)-Blepharocalyxin D and Analogues

An efficient strategy for the total synthesis of (-)-blepharocalyxin D and an analogue is described. The key step involves an acid-mediated cascade process in which reaction of methyl 3,3-dimethoxypropanoate with γ,δ-unsaturated alcohols possessing diastereotopic styrenyl groups gives trans-fused bicyclic lactones with the creation of two rings and four stereocenters in one pot.

Synthesis of Decahydropyrrolo[2,1,5-cd]indolizine through Consecutive [2 + 3] Cycloadditions and 6-Exo-Trig Cyclization

Azomethine ylide formed from glycine methyl ester and cinnamaldehyde adds to N-phenylmaleimide to form pyrrolidine derivative, further treatment of which with cinnamaldehyde and N-phenylmaleimide affords the second [2 + 3] cycloaddition adduct, a pyrrolizine derivative with two styrenyl groups at the 3,5-positions. Addition of ICl to the pyrrolizine derivative results in the 6-exo-trig cyclization of the styrenyl groups to form a cycl[3.2.2]azine derivative. The reactions are highly stereoselective affording 11 chiral carbons in three steps. The structure of the cycl[3.2.2]azine derivative was determined by single-crystal X-ray analysis.

Quantum chemical studies on para-substituted styrenyl fullerene. Study of substitution effects on structural and electronic properties

Quantum chemical investigations on para-substituted styrenyl fullerene derivatives with substituents linked to para position of styrenyl group have been carried out. The density functional theory (DFT) have been used in this study with B3LYP functional and the modest 3-21G* basis sets. The substituents were variable donating and withdrawing to study the effect of such structural change on the structural and electronic properties of the studied molecules.

Well-Defined Polymers Bearing Pendent Alkene Functionalities via Selective RAFT Polymerization.

A facile synthetic approach for the preparation of well-defined (co)polymers bearing pendent alkene functionalities was established by selective reversible addition-fragmentation chain transfer (RAFT) (co)polymerization. A divinyl monomer 4-(3'-buten-1'-oxy)-2,3,5,6-tetrafluorostyrene (1) with a styrenyl group and a pendent alkene group was synthesized. Due to a very high reactivity of the styrenyl group relative to the alkene group in 1, functional fluoro(co)polymers with both well-defined structures and pendent alkene groups were prepared by RAFT polymerizations of 1 and copolymerization of 1 with pentafluorostyrene (PFS). Alkene-functionalized diblock copolymers were also prepared by RAFT copolymerization of 1 with PFS or styrene, extending from a poly(styrene-alt-maleic anhydride) macro-chain transfer agent. Hydrolysis and ammonolysis of these copolymers resulted in amphiphilic diblock fluorocopolymers with alkene-functionalized hydrophobic segments, which were shown to form internally-functionalized micelles in THF-water.

Study of photocrosslinkable polysiloxanes bearing gem di-styrenyl groups: Synthesis and thermal properties

The synthesis of photocrosslinkable polysiloxanes containing gem di-oxaalkylene styrenyl groups and gem di-urethane-α-methyl styrenyl groups has been performed by copolycondensation of α,ω-dihydroxy polydimethyl siloxanes and dichlorosilanes bearing either cyclic acetal groups or Si–H groups (onto which the cyclic acetal groups are further added) and dichlorosilanes bearing alkyl groups. The introduction of styrenyl groups was then achieved by hydrolysis of the acetal groups into the corresponding alcohols followed by reaction with chloromethyl styrene or with 3-isopropenyl-α,α- dimethylbenzyl isocyanate. The structure of the different products synthesized was determined by IR, 1H, 13C and 29Si NMR spectroscopies. The thermal properties of the polysiloxanes bearing gem di-styrenyl groups have been studied at low and high temperatures. These products have been crosslinked under UV, in the presence of a cationic photoinitiator, and showed very good release paper properties.

Synthesis and applications of polysiloxanes containing photocrosslinkable oxaalkylene styrenyl groups

The synthesis of photocrosslinkable polysiloxanes containing (or not) alkylfluorinated groups and oxaalkylene styrenyl groups was performed. It was carried out either by modification of commercially available polysiloxanes bearing Si-vinyl groups which were reacted with 2-mercaptoethanol followed by addition of p-(chloromethyl)styrene, or by copolycondensation of α,ω-dihydroxy polydimethylsiloxanes and dichlorosilanes bearing acetoxy groups and dichlorosilanes bearing fluorinated groups. The introduction of styrene groups was then achieved by hydrolysis of the acetoxy group into the corresponding alcohol followed by reaction with p-(chloromethyl)styrene. The structure of the final products was determined by IR, 1 H and 13 C NMR spectroscopies. These products have been crosslinked under UV, in the presence of a cationic photoinitiator, and showed very good release paper properties and a good thermal resistance. The properties are enhanced when the copolymers contain fluorinated groups.

Halodecarboxylation of α,β-Unsaturated Carboxylic Acids bearing Aryl and Styrenyl Group at β-Carbon with Oxone® and Sodium Halide

Reaction of a,b-unsaturated carboxylic acid bearing aryl and styrenyl group at b-carbon with Oxone ® and sodium halide in

ChemInform Abstract: Halodecarboxylation of α,β‐Unsaturated Carboxylic Acids Bearing Aryl and Styrenyl Group at β‐Carbon with Oxone® and Sodium Halide.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Formation and Characterization of Covalently Bound Polyelectrolyte Brushes

Poly(4-vinylpyridine) (PVP), functionalized at one terminus with a styrenyl group, was end-grafted to vinyl-functionalized self-assembled monolayers by UV irradiation in 1-methyl-2-pyrrolidinone. In this solvent and with oxygen excluded, surface reactions appeared to be selectively limited to the polymer terminus. The dry film thickness was determined by ellipsometry and the grafted amount by FTIR-ATR (Fourier transform infrared spectroscopy in attenuated total reflection). Controlled amounts of positive charge were introduced into the grafted chains by alkylation with a 2.5% solution of CH3I in dimethylformamide (DMF). FTIR-ATR was used to quantify the extent of alkylation, from 10% to 96%. These polyelectrolyte brushes will comprise a model system for studying polyelectrolytes at surfaces.