scholarly journals Azaacenes Based Electroactive Materials: Preparation, Structure, Electrochemistry, Spectroscopy and Applications—A Critical Review

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5155
Author(s):  
Kamil Kotwica ◽  
Ireneusz Wielgus ◽  
Adam Proń
Keyword(s):  
Critical Review ◽  
Field Effect Transistors ◽  
Spectroscopic Properties ◽  
Molecular Shape ◽  
Structural Features ◽  
Redox Potentials ◽  
Preparation Methods ◽  
Organic Memory Devices ◽  
Distribution Mode ◽  
Reported Data

This short critical review is devoted to the synthesis and functionalization of various types of azaacenes, organic semiconducting compounds which can be considered as promising materials for the fabrication of n-channel or ambipolar field effect transistors (FETs), components of active layers in light emitting diodes (LEDs), components of organic memory devices and others. Emphasis is put on the diversity of azaacenes preparation methods and the possibility of tuning their redox and spectroscopic properties by changing the C/N ratio, modifying the nitrogen atoms distribution mode, functionalization with electroaccepting or electrodonating groups and changing their molecular shape. Processability, structural features and degradation pathways of these compounds are also discussed. A unique feature of this review concerns the listed redox potentials of all discussed compounds which were normalized vs. Fc/Fc+. This required, in frequent cases, recalculation of the originally reported data in which these potentials were determined against different types of reference electrodes. The same applied to all reported electron affinities (EAs). EA values calculated using different methods were recalculated by applying the method of Sworakowski and co-workers (Org. Electron. 2016, 33, 300–310) to yield, for the first time, a set of normalized data, which could be directly compared.

scholarly journals Redox-State Dependent Spectroscopic Properties of Porous Organic Polymers Containing Furan, Thiophene, and Selenophene

2017 ◽  
Vol 70 (11) ◽  
pp. 1227 ◽  
Author(s):  
Carol Hua ◽  
Stone Woo ◽  
Aditya Rawal ◽  
Floriana Tuna ◽  
James M. Hook ◽  
...  
Keyword(s):  
Solid State ◽  
Redox State ◽  
Spectroscopic Properties ◽  
Structural Features ◽  
Organic Polymers ◽  
Stimuli Responsive ◽  
Porous Organic Polymers ◽  
Paramagnetic Resonance ◽  
Responsive Materials ◽  
State Dependent

A series of electroactive triarylamine porous organic polymers (POPs) with furan, thiophene, and selenophene (POP-O, POP-S, and POP-Se) linkers have been synthesised and their electronic and spectroscopic properties investigated as a function of redox state. Solid state NMR provided insight into the structural features of the POPs, while in situ solid state Vis-NIR and electron paramagnetic resonance spectroelectrochemistry showed that the distinct redox states in POP-S could be reversibly accessed. The development of redox-active porous organic polymers with heterocyclic linkers affords their potential application as stimuli responsive materials in gas storage, catalysis, and as electrochromic materials.

scholarly journals Early Neurological Assessment and Long-Term Neuromotor Outcomes in Late Preterm Infants: A Critical Review

Medicina ◽  
2020 ◽  
Vol 56 (9) ◽  
pp. 475
Author(s):  
Domenico M. Romeo ◽  
Martina Ricci ◽  
Maria Picilli ◽  
Benedetta Foti ◽  
Giorgia Cordaro ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Preterm Infants ◽  
Gestational Age ◽  
Critical Review ◽  
Neonatal Period ◽  
Late Preterm ◽  
Motor Disorder ◽  
Neurological Assessment ◽  
Late Preterm Infants ◽  
Reported Data

Background and Objectives: Late preterm (LP) infants (born between 34 and 36 weeks of gestational age) are considered at higher risk of neonatal morbidities, mortality, and neurological impairments than full-term born infants (FT). The aim of this study was to provide a critical review of the literature outlining the different aspects of neurological function reported both in the neonatal period and in the follow up of late preterm infants. Materials and Methods: A comprehensive search of the MEDLINE, Embase, PsycINFO, and CINAHL electronic databases was made, using the following search terms: ‘Late preterm infants’, ‘Near term infants’, ‘neurological assessment’, ‘neurological outcome’, ‘neuromotor outcome’, cerebral palsy’, ‘CP’, ‘motor impairment’, including all the studies reporting clinical neurological assessment of LP (including both neonatal period and subsequent ages). Results: A total of 35 articles, comprising 301,495 children, were included as fulfilling the inclusion criteria: ten reported neonatal neurological findings, seven reported data about the first two years after birth, eighteen reported data about incidence of CP and motor disorder during the infancy. Results showed a more immature neurological profile, explored with structured neurological assessments, in LP infants compared with FT infants. The LP population also had a higher risk of developing cerebral palsy, motor delay, and coordination disorder. Conclusion: LP had a higher risk of neurological impairments than FT infants, due to a brain immaturity and an increased vulnerability to injury, as the last weeks of gestational age are crucial for the development of the brain.

scholarly journals Noncovalent Bonds, Spectral and Thermal Properties of Substituted Thiazolo[2,3-b][1,3]thiazinium Triiodides

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 506 ◽  
Author(s):  
Irina Yushina ◽  
Natalya Tarasova ◽  
Dmitry Kim ◽  
Vladimir Sharutin ◽  
Ekaterina Bartashevich
Keyword(s):  
Electron Density ◽  
Noncovalent Interactions ◽  
Material Design ◽  
Spectroscopic Properties ◽  
Structural Features ◽  
Halogen Bonds ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Pairwise Interactions ◽  
Noncovalent Bonds

The interrelation between noncovalent bonds and physicochemical properties is in the spotlight due to the practical aspects in the field of crystalline material design. Such study requires a number of similar substances in order to reveal the effect of structural features on observed properties. For this reason, we analyzed a series of three substituted thiazolo[2,3-b][1,3]thiazinium triiodides synthesized by an iodocyclization reaction. They have been characterized with the use of X-ray diffraction, Raman spectroscopy, and thermal analysis. Various types of noncovalent interactions have been considered, and an S…I chalcogen bond type has been confirmed using the electronic criterion based on the calculated electron density and electrostatic potential. The involvement of triiodide anions in the I…I halogen and S…I chalcogen bonding is reflected in the Raman spectroscopic properties of the I–I bonds: identical bond lengths demonstrate different wave numbers of symmetric triiodide vibration and different values of electron density at bond critical points. Chalcogen and halogen bonds formed by the terminal iodine atom of triiodide anion and numerous cation…cation pairwise interactions can serve as one of the reasons for increased thermal stability and retention of iodine in the melt under heating.

Photoswitching of Redox Potentials and Spectroscopic Properties in the UV/vis Region

2005 ◽  
Vol 60 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Nedko Drebov ◽  
Nikolai Tyutyulkov ◽  
Stojan Karabunarliev ◽  
Fritz Dietz
Keyword(s):  
Spectroscopic Properties ◽  
Visible Spectral Region ◽  
Redox Potentials ◽  
Electron Systems ◽  
Excitation Energies ◽  
Reduction Potentials ◽  
Open Ring ◽  
Wavelength Absorption ◽  
Donor Acceptor ◽  
Ct Transitions

The photoswitching of optical and electrochemical properties of di-donor, di-acceptor and donor-acceptor substituted photochromic tetrahydropyrene - [2,2]metacyclophanene and dihydropyrene - [2,2]metacyclophanediene systems has been studied theoretically. A switching of the halfwave oxidation and reduction potentials should be possible in the case of bis(pyridinium) and bis(hydroxyphenyl) substituted systems. Because of the relatively great perturbation of the planarity of the π-electron systems by large torsion of the substituents out of the π-electron structure of the photochromic system and the stair-like structure of the ring-opened isomer, relatively large excitation energies for CT transitions have been calculated with the AM1-CI procedure. The ring-closed structures should absorb in the visible spectral region, and the open-ring isomers should have a longest-wavelength absorption in the UV region.

scholarly journals Substitution Effect on the Charge Transfer Processes in Organo-Imido Lindqvist-Polyoxomolybdate

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 44 ◽  
Author(s):  
Patricio Hermosilla-Ibáñez ◽  
Kerry Wrighton-Araneda ◽  
Walter Cañón-Mancisidor ◽  
Marlen Gutiérrez-Cutiño ◽  
Verónica Paredes-García ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Theoretical Study ◽  
Bathochromic Shift ◽  
Substitution Effect ◽  
Spectroscopic Properties ◽  
Electrochemical Studies ◽  
Redox Potentials ◽  
Metal Centre ◽  
Transfer Processes ◽  
Organic Fragment

Two new aromatic organo-imido polyoxometalates with an electron donor triazole group ([n-Bu4N]2[Mo6O18NC6H4N3C2H2]) (1) and a highly conjugated fluorene ([n-Bu4N]2[Mo6O18NC13H9]) (2) have been obtained. The electrochemical and spectroscopic properties of several organo-imido systems were studied. These properties were analysed by the theoretical study of the redox potentials and by means of the excitation analysis, in order to understand the effect on the substitution of the organo-imido fragment and the effect of the interaction to a metal centre. Our results show a bathochromic shift related to the charge transfer processes induced by the increase of the conjugated character of the organic fragment. The cathodic shift obtained from the electrochemical studies reflects that the electronic communication and conjugation between the organic and inorganic fragments is the main reason of this phenomenon.

scholarly journals Functional Nanofibrous Biomaterials of Tailored Structures for Drug Delivery—A Critical Review

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 522
Author(s):  
Zhen Li ◽  
Shunqi Mei ◽  
Yajie Dong ◽  
Fenghua She ◽  
Yongzhen Li ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Extracellular Matrix ◽  
Critical Review ◽  
Polymeric Materials ◽  
Structural Features ◽  
Advantages And Disadvantages ◽  
Drug Molecules ◽  
Wide Range ◽  
Polymeric Nanofibers ◽  
Insight Into

Nanofibrous biomaterials have huge potential for drug delivery, due to their structural features and functions that are similar to the native extracellular matrix (ECM). A wide range of natural and polymeric materials can be employed to produce nanofibrous biomaterials. This review introduces the major natural and synthetic biomaterials for production of nanofibers that are biocompatible and biodegradable. Different technologies and their corresponding advantages and disadvantages for manufacturing nanofibrous biomaterials for drug delivery were also reported. The morphologies and structures of nanofibers can be tailor-designed and processed by carefully selecting suitable biomaterials and fabrication methods, while the functionality of nanofibrous biomaterials can be improved by modifying the surface. The loading and releasing of drug molecules, which play a significant role in the effectiveness of drug delivery, are also surveyed. This review provides insight into the fabrication of functional polymeric nanofibers for drug delivery.

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