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1.
J Am Chem Soc ; 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39079042

RESUMO

Solid-phase polymer synthesis, historically rooted in peptide synthesis, has evolved into a powerful method for achieving sequence-controlled macromolecules. This study explores solid-phase polymer synthesis by covalently immobilizing growing polymer chains onto a poly(ethylene glycol) (PEG)-based resin, known as ChemMatrix (CM) resin. In contrast to traditional hydrophobic supports, CM resin's amphiphilic properties enable swelling in both polar and nonpolar solvents, simplifying filtration, washing, and drying processes. Combining atom transfer radical polymerization (ATRP) with solid-phase techniques allowed for the grafting of well-defined block copolymers in high yields. This approach is attractive for sequence-controlled polymer synthesis, successfully synthesizing di-, tri-, tetra-, and penta-block copolymers with excellent control over the molecular weight and dispersity. The study also delves into the limitations of achieving high molecular weights due to confinement within resin pores. Moreover, the versatility of the method is demonstrated through its applicability to various monomers in organic and aqueous media. This straightforward approach offers a rapid route to developing tailored block copolymers with unique structures and functionalities.

2.
Macromol Rapid Commun ; 45(3): e2300458, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37955104

RESUMO

A straightforward approach is employed to synthesize methylene-bridged poly(hetero aromatic)s based on furan, pyrrole, thiophene, and thiophene derivatives. The process involves an electrophilic aromatic substitution reaction facilitated by a visible light-initiated system consisting of manganese decacarbonyl and an iodonium salt. The approach mainly relies on the formation of halomethylium cation, the attack of this cation to heteroaromatic, regeneration of methylium cation on the heteroaromatic, and reactivity differences between halomethylium and heteroaromatic methylium cations for successful polymerizations. This innovative synthetic strategy lead to the formation of polymers with relatively high molecular weights as the stoichiometric imbalance between the comonomers increased. Accordingly, these newly obtained polymers exhibit remarkable fluorescence properties, even at excitation wavelengths as low as 330 nm. Moreover, by harnessing the halogens at chain ends of homopolymers, block copolymers are successfully synthesized, offering opportunities for tailored applications in diverse fields.


Assuntos
Luz , Metano/análogos & derivados , Polímeros , Polimerização , Cátions , Tiofenos
3.
Angew Chem Int Ed Engl ; 63(18): e202316431, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38012084

RESUMO

Carbon nanomaterials, specifically carbon dots and carbon nitrides, play a crucial role as heterogeneous photoinitiators in both radical and cationic polymerization processes. These recently introduced materials offer promising solutions to the limitations of current homogeneous systems, presenting a novel approach to photopolymerization. This review highlights the preparation and photocatalytic performance of these nanomaterials, emphasizing their application in various polymerization techniques, including photoinduced i) free radical, ii) RAFT, iii) ATRP, and iv) cationic photopolymerization. Additionally, it discusses their potential in addressing contemporary challenges and explores prospects in this field. Moreover, carbon nitrides, in particular, exhibit exceptional oxygen tolerance, underscoring their significance in radical polymerization processes and allowing their applications such as 3D printing, surface modification of coatings, and hydrogel engineering.

4.
Psychopathology ; 56(6): 440-452, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37062284

RESUMO

INTRODUCTION: Despite the similarities in poor social competence and clinical manifestations of poor social behavior, no study has compared the theory of mind performance between social anxiety disorder (SAD) and schizophrenia, considering the effect of social-evaluative anxiety and neurocognitive functions. In our study, we aimed to compare the theory of mind functions and social-evaluative anxiety between patients with SAD and schizophrenia and healthy controls and to examine the relationship between the theory of mind, neurocognitive skills, and social-evaluative anxiety. METHODS: Thirty-four consecutive patients with schizophrenia, 29 patients with SAD, and 30 controls matched by age, education level, and sex were enrolled in the study. Structured Clinical Interview for DSM, Beck Depression Inventory, Liebowitz Social Anxiety Scale, Theory of Mind measures (Reading the Mind in the Eyes Test, Hinting Task, Faux Pas Test), Social Appearance Anxiety Scale, Fear of Positive Evaluation Scale, Fear of Negative Evaluation Scale-Short Form, and neuropsychological tests were administered to all participants. RESULTS: A greater significant deterioration in theory of mind and neurocognitive functions was found in patients with schizophrenia compared to those with SAD and healthy controls. Social evaluation anxiety was highest in patients with SAD. Although social-evaluative anxiety was associated with the theory of mind function in schizophrenia, only fear of positive evaluation was associated with SAD. In all groups, neither theory of mind nor neurocognitive ability measures were correlated with social anxiety levels and related symptoms. CONCLUSIONS: The impaired theory of mind functioning detected in our study is more prominent in the schizophrenia group and largely independent of anxiety in schizophrenia and SAD. Although social evaluation anxiety, as a transdiagnostic concept, seems to be independent of theory of mind function in general, fear of positive evaluation seems to be associated with hinting in both disorders.


Assuntos
Fobia Social , Esquizofrenia , Teoria da Mente , Humanos , Esquizofrenia/diagnóstico , Medo , Ansiedade , Testes Neuropsicológicos
5.
Angew Chem Int Ed Engl ; 61(23): e202117377, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35128771

RESUMO

The application of photochemistry in polymer synthesis is of interest due to the unique possibilities offered compared to thermochemistry, including topological and temporal control, rapid polymerization, sustainable low-energy processes, and environmentally benign features leading to established and emerging applications in adhesives, coatings, adaptive manufacturing, etc. In particular, the utilization of photochemistry in controlled/living polymerizations often offers the capability for precise control over the macromolecular structure and chain length in addition to the associated advantages of photochemistry. Herein, the latest developments in photocontrolled living radical and cationic polymerizations and their combinations for application in polymer syntheses are discussed. This Review summarizes and highlights recent studies in the emerging area of photoinduced controlled/living polymerizations. A discussion of mechanistic details highlights differences as well as parallels between different systems for different polymerization methods and monomer applicability.


Assuntos
Polímeros , Estrutura Molecular , Fotoquímica , Polimerização , Polímeros/química
6.
Macromol Rapid Commun ; 42(7): e2000686, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33570222

RESUMO

A new visible light induced step-growth polymerization of dibromoxylene, and diols using dimanganese decacarbonyl and diphenyliodonium salt is described. The polymerization is suggested to proceed by substitution reaction between dixylenium cations formed upon visible light irradiation in the presence of dimanganese decacarbonyl and diphenyl iodonium salt. For the described substitution reaction with diols as nucleophilic component, the scope of the process is studied. Furthermore, the presence of halide groups at chain ends of the resulting polymers provided the possibility of initiating subsequent free radical and free radical promoted cationic resulting in the formation of polyether-based block copolymers.


Assuntos
Luz , Polímeros , Cátions , Radicais Livres , Polimerização
7.
Macromol Rapid Commun ; 42(14): e2100166, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34142403

RESUMO

Various ligation processes have recently become a powerful tool in synthetic polymer chemistry. Herein, the use of a new photochemical ligation process as a versatile approach for the cross-linking polymerization, functionalization of polymer chain ends, and surface modification of various materials such as silica and graphene oxide, is demonstrated. The process is based on the formation of urethane linkages by the reaction of photochemically in situ generated isocyanates from benzoyl azides with hydroxyl moieties in the presence of organobase, bicyclo[2.2.2]-1,4-diazaoctane (DABCO) under ambient conditions. The intermediates and obtained materials are characterized by NMR, FTIR, TGA, and TEM analyses. It is believed that this simple and efficient ligation process will expand future applications to fabricate complex macromolecular structures, biomaterials, and gels.


Assuntos
Azidas , Polímeros , Materiais Biocompatíveis , Estrutura Molecular , Polimerização
8.
J Am Chem Soc ; 140(40): 12728-12731, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30257091

RESUMO

A novel method for photochemical step-growth synthesis of poly( N-ethylcarbazole) (PEC) via consecutive diphenyl iodonium hexafluorophospate (Ph2I+PF6-) mediated electron transfer and coupling reactions is reported. The photoinduced electron transfer reaction of the excited N-ethylcarbazole (EC) in the presence of Ph2I+PF6- as the oxidizing salt proceeded efficiently giving EC radical cations (EC+•). Subsequently, the protons released concomitantly with coupling of two EC radical cations. The successive reactions involving excitation, electron transfer, proton release, and coupling lead to the formation of PEC. The electrochemical properties and surface morphology of the thin films of the formed polymers before and after dedoping were investigated by cyclic voltammetry, differential pulse voltammetry, and atomic force microscopy techniques, respectively.

9.
Macromol Rapid Commun ; 37(13): 1046-51, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27168378

RESUMO

Thioxanthone (TX) and its derivatives, which are widely used as photoinitiators in UV curing technology, hold promising research interest in biological applications. In particular, the use of TXs as anticancer agent has recently been manifested as an outstanding additional property of this class of molecules. Incorporation of TX molecules into specially designed polymers widens their practical use in such applications. In this study, two water-soluble, biocompatible, and stable polymers, namely poly(vinyl alcohol) and poly(ethylene glycol), possessing TX moieties at the side chains and chain ends, respectively, are prepared and used as anticancer and radiotherapy agents. The findings confirm that both polymers are potential candidates for therapeutic agents as they possess useful features including water-solubility, radiosensitizer effect, and anticancer activity in a polymeric scaffold.


Assuntos
Antineoplásicos/farmacologia , Quimiorradioterapia , Neoplasias/terapia , Polietilenoglicóis/farmacologia , Álcool de Polivinil/farmacologia , Xantonas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Álcool de Polivinil/síntese química , Álcool de Polivinil/química , Relação Estrutura-Atividade , Tioxantenos/síntese química , Tioxantenos/química , Tioxantenos/farmacologia , Células Tumorais Cultivadas , Xantonas/síntese química , Xantonas/química
10.
Macromol Rapid Commun ; 36(10): 923-8, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25855091

RESUMO

A novel one-component type II polymeric photoinitiator, poly(vinyl alcohol)-thioxanthone (PVA-TX), is synthesized by a simple acetalization process and characterized. PVA-TX enables photopolymerization of methyl methacrylate and acrylamide in both organic and aqueous media. Photopolymerization proceeds even in the absence of a co-initiator since PVA-TX possesses both chromophoric and hydrogen donating sites in the structure.


Assuntos
Radicais Livres/química , Álcool de Polivinil/química , Xantonas/química , Acrilamida/química , Dimetilformamida/química , Luz , Metilmetacrilato/química , Processos Fotoquímicos , Polimerização , Solventes , Tioxantenos/química , Água/química
11.
Turk Psikiyatri Derg ; 35(1): 14-23, 2024.
Artigo em Inglês, Turco | MEDLINE | ID: mdl-38556933

RESUMO

OBJECTIVE: This study aimed to compare the criminal, sociodemographic and clinical characteristics, paraphilic behaviors, sexual attitudes, gender perceptions, and rape-related beliefs of people assessed for criminal liability for rape against adults and children. METHOD: The study compared 40 people investigated for criminal liability for rape against an adult (RAA) with 40 individuals investigated for criminal liability for crime of rape against a child (RAC), and 43 age, sex and education matched individuals without any sexual crime history using the Structured Clinical Interview form for DSM-5 disorders, Hendrick Brief Sexual Attitude Scale, Gender Perception Scale, Illinois Rape Myth Acceptance Scale, and Barratt Impulsiveness Scale-11. RESULTS: All participants were male. There was no difference between the groups in terms of lifelong or existing psychiatric diseases. All participants had full criminal responsibility during the crime. No participant in any group was diagnosed with a paraphilic disorder. It was determined that people in both RAC and RAA groups tended to use sexuality as a tool, paid less attention to birth control methods, had a far less egalitarian perception of gender, and their myths about rape were significantly higher compared to the control group. The control group was much more impulsive than the sex offenders. CONCLUSION: Our results show that the act of sexual assault should not be explained only by impulsivity or psychiatric disorders, and that gender perception and sexual myths may also be influential. The fact that all individuals had full criminal responsibility emphasizes the need for more research on the social and cultural origins of sexual violence.


Assuntos
Vítimas de Crime , Criminosos , Estupro , Delitos Sexuais , Adulto , Criança , Humanos , Masculino , Feminino , Estupro/psicologia , Identidade de Gênero , Atitude , Comportamento Sexual , Vítimas de Crime/psicologia
12.
Appl Neuropsychol Adult ; : 1-9, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36652595

RESUMO

This study aims to compare the Theory of Mind (ToM) functions in the siblings and offspring of female Schizophrenia patients in an evaluation of the association between neurocognitive functions and ToM. A battery of ToM tests (Reading the Mind in the Eyes Test, Hinting Test and Faux Pas Test) and neurocognitive tests (Digit Span Test, Corsi Block Test, Digit Symbol Substitution Test, Rey's Auditory Verbal Learning Test, Trail Making Test, The Stroop Test, Wisconsin Card Sorting Test) were used to assess 31 offspring, 29 siblings of female schizophrenia patients and 28 healthy controls (HC). When the ToM functions of the offspring, siblings and HC groups in the present study are compared, no significant difference is identified between the offspring and sibling groups in Hinting, Faux Pas and Eyes tests, while Hinting test performance of the sibling group was significantly lower than those of the HCs. Neurocognitive functions are more affected both in offspring and siblings than HC. Although it was determined that ToM deficits of the patients' relatives were not as prominent as their neurocognitive functions, ToM is an endophenotype candidate in schizophrenia.

13.
ACS Macro Lett ; 12(8): 1173-1178, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37531639

RESUMO

Fast bulk depolymerization of poly(n-butyl methacrylate) and poly(methyl methacrylate), prepared by atom transfer radical polymerization (ATRP), is reported in the temperature range between 150 and 230 °C. Depolymerization of Cl-terminated polymethacrylates was catalyzed by a CuCl2/TPMA complex (0.022 or 0.22 equiv vs P-Cl) and was studied using TGA, also under isothermal conditions. Relatively rapid 5-20 min depolymerization was observed at 230 and 180 °C. The preparative scale reactions were carried out using a short-path distillation setup with up to 84% depolymerization within 15 min at 230 °C.

14.
Langmuir ; 28(21): 8035-45, 2012 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-22548322

RESUMO

In this paper we describe a novel methodology for grafting polymers via radical photopolymerization initiated on gold surfaces by aryl layers from diazonium salt precursors. The parent 4-(dimethylamino)benzenediazonium salt was electroreduced on a gold surface to provide 4-(dimethylamino)phenyl (DMA) hydrogen donor layers; free benzophenone in solution was used as a photosensitizer to strip hydrogen from the grafted DMA. This system permitted efficient surface initiation of photopolymerization of 2-hydroxyethyl methacrylate. The resulting poly(2-hydroxyethyl methacrylate) (PHEMA) grafts were found to be very adherent to the surface as they resist total failure after being soaked in the well-known paint stripper methyl ethyl ketone. The PHEMA grafts were reacted with 1,1'-carbonyldiimidazole to yield carbamate groups that are able to react readily with amino groups from proteins. The final surface consisted of protein-functionalized PHEMA grafts where bovine serum albumin (BSA) protein is specifically linked to the grafts by covalent bonds. We used X-ray photoelectron spectroscopy to monitor the chemical changes at the gold surface all along the process from the neat gold to the end-protein-functionalized polymer grafts: the PHEMA graft thickness ranged from 7 to 27 nm, and the activation by 1,1'-carbonyldiimidazole reached 37% of the OH groups, which was sufficient for 90% surface coverage of the grafts by BSA. This work conclusively provides a new approach for bridging reactive and functional polymers to surfaces via aryl diazonium salts in a simple, fast, and efficient approach of importance in biomedical and other applications.


Assuntos
Hidrogênio/química , Metilaminas/química , Poli-Hidroxietil Metacrilato/síntese química , Radicais Livres/química , Metilaminas/síntese química , Estrutura Molecular , Processos Fotoquímicos , Poli-Hidroxietil Metacrilato/química , Polimerização , Sais/síntese química , Sais/química , Propriedades de Superfície
15.
ACS Macro Lett ; 11(3): 342-346, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35575368

RESUMO

A versatile strategy for the fabrication of block copolymers by the combination of two discrete living polymerization techniques─reversible complexation mediated living radical polymerization (RCMP) and photoinduced radical oxidation addition deactivation (PROAD) processes─is reported. First, RCMP is conducted to yield poly(methyl methacrylate) with iodide end groups (PMMA-I). In the following step, PMMA-I is used as macroinitiator for living PROAD cationic polymerization of isobutyl vinyl ether. Successful formation of the block copolymers is confirmed by 1H NMR, FT-IR, GPC, and DSC investigations.


Assuntos
Polímeros , Polimetil Metacrilato , Cátions/química , Polimerização , Polimetil Metacrilato/química , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Macromol Rapid Commun ; 32(23): 1906-9, 2011 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-21910152

RESUMO

Current preparation methods for hydrogels based on redox or photopolymerization of water soluble monomers are simple to use, and flexible, but have the drawback of requiring additional modification steps for tuning or introducing properties for specific purposes. We have devised a simple and rapid synthetic strategy to prepare hydrogels possessing reactive sites to incorporate any molecules of interest by "Click Chemistry". The strategy is based on the use of propargyl acrylamide (PAm) as comonomer together with acrylamide (AAm) and N,N'-methylene bisacrylamide (BAAm) as crosslinker in photoinitiated polymerization. With the selective reactivity of photochemically generated free radicals towards acrylic function of PAm, hydrogels with clickable acetylene groups can be prepared in one pot, one step manner. Based on the acetylene functionality, any molecule possessing azide groups can be conjugated onto hydrogel by "Click Chemistry" as demonstrated on the example of fluoroscent azide functional pyrene.


Assuntos
Acrilamida/química , Acrilamidas/química , Química Click/métodos , Hidrogéis/síntese química , Fotoquímica/métodos , Hidrogéis/química
17.
Chem Commun (Camb) ; 57(44): 5398-5401, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33942841

RESUMO

A novel visible light induced step-growth polymerization to form poly(phenylene methylene) by electrophilic aromatic substitution reactions is described. The effect of different nucleophilic aromatic molecules on polymerization has been investigated. The possibility of combining step-growth polymerization with conventional free radical and free radical promoted cationic polymerizations through photoinduced chain-end activation has been demonstrated. Highly fluorescent fibers of the resulting block copolymers were obtained using the electrospinning technique. The versatile photoinduced step-growth polymerization process reported herein paves the way for a new generation of polycondensates and their combination with chain polymers that cannot be obtained by conventional methods.

18.
ACS Macro Lett ; 10(6): 679-683, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35549101

RESUMO

In the drive toward the development of efficient and stable inorganic semiconductor materials with broadband solar absorption ability to induce various photochemical processes is a highly attractive research field. In this study, two-dimensional (2D) few-layer black phosphorus (BP) exfoliated in a solvent is utilized as photocatalyst to initiate the polymerization of various monomers under visible and near-IR (NIR) light irradiation. Upon the light exposure, few-layer BP generates excited electrons and holes, which undergo electron transfer reactions with the onium salts to form free radicals capable of initiating free radical polymerization. Among the onium salts tested, aryldiazonium salt was found to be the most efficient in the photopolymerization process owing to its favorable reduction potential with the conduction edge potential of BP. The presented strategy also provides the possibility for the in situ preparation of BP-polymer composite materials.

19.
Des Monomers Polym ; 23(1): 134-140, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-33029081

RESUMO

A completely metal-free and environmentally friendly strategy is demonstrated for the preparation of graft copolymers by combining photoinduced Atom Transfer Radical Polymerization (ATRP) and Ring Opening Polymerization (ROP). Polymerizations are simultaneously realized in a one-pot manner. For this purpose, bare vinyl monomers, vinyl monomers with hydroxyl functional groups, and lactone monomers were simultaneously polymerized under visible light using specific catalysts. While vinyl monomers construct the main chain, the lactone monomers were polymerized from the hydroxyl functions present at the side chain. Spectral and chromatographic analyses prove that the utilized strategy is successful in the preparation of graft copolymers controlled molecular weights and narrow distributions.

20.
Polymers (Basel) ; 11(10)2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31569688

RESUMO

A completely metal-free strategy is demonstrated for the preparation of star copolymers by combining atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP) for the syntheses of block copolymers. These two different metal-free controlled/living polymerizations are simultaneously realized in one reaction medium in an orthogonal manner. For this purpose, a specific core with functional groups capable of initiating both polymerization types is synthesized. Next, vinyl and lactone monomers are simultaneously polymerized under visible light irradiation using specific catalysts. Spectral and chromatographic evidence demonstrates the success of the strategy as star copolymers are synthesized with controlled molecular weights and narrow distributions.

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