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Polymer Semiconductors
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Polymers in Energy Conversion and Storage, 2022
Moises Bustamante-Torres, Jocelyne Estrella-Nuñez, Odalys Torres, Sofía Abad-Sojos, Bryan Chiguano-Tapia, Emilio Bucio
Most of the polymers that have worked optimally for PTFTs are p-channeled. To improve hole-transporting polymers, a balance is made among the HOMO energy levels, which should be between −5 and −5.5 eV in normal conditions. As a result, the EHOMO presents an inverse behavior to the ionization potential. This condition gives rise to easy air-induced oxidation, and the acceptor sites quickly begin to complicate the environmental stability of the PTFT. Then, the current flow is excellent, and high mobility values can be obtained. The most common problem for these transistors is high voltage thresholds. The addition of substituents improves their solubility and stability (Facchetti 2011). The positioning of the alkyl groups as part of the side chain of the polymer allows the transistors to have greater mobility (Lei, Dou and Pei 2012).
Free-Wilson Model
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Bogdan Bumbăcilă, Mihai V. Putz
The Free & Wilson model relates structure to its biological potency. In some situations, fragments/substituents of a molecule can be considered as a unit that can also be substituted. An R group, a substituent can be a molecular fragment that can be attached to a molecule. The molecule can be composed by a molecular core and one or more R groups, different or not between each other. In their first model, Free, and Wilson described a common molecular core with two substituents: R1 and R2. R1 could have been H or CH3 and R2−N(CH3)2 or N(C2H5)2. Four analog molecules could be described by the combinations made with these substituents. (Free et al., 1964) A matrix with the numbers 0 and 1 can be created, where these 2 numbers are indicating the absence or presence of a certain substituent on the molecular scaffold. Then the linear regression formula which is relating the molecular structure with the potency/biological activity is drawn as it was previously presented.
Symbols, Terminology, and Nomenclature
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
e rst part of this table lists substituent groups and their line formulas. A substituent group is de ned by IUPAC as a group that replaces one or more hydrogen atoms attached to a parent structure. Such groups are sometimes called radicals, but IUPAC now reserves the term radical for a free molecular species with unpaired electrons. IUPAC does not recommend some of these names, which are marked here with asterisks (e.g., amyl*), but they are included in this list because they are often encountered in the older literature. Substituent group names that are formed Substituent Groups
Synthesis, characterization, and optical studies of pentoxy-substituted tetrakis(pentafluorobenzyloxy)phthalocyanines
Published in Journal of Coordination Chemistry, 2018
Mukaddes Özçeşmeci, Idris Sorar, Ibrahim Özçeşmeci, Esin Hamuryudan
The phthalocyanines (Pcs), obtained in 1907 by chance, are a very important class of compounds whose structure was elucidated in the 1930s. The importance of Pcs is due to their application in a wide range of fields, such as pigments, dyes, photodynamic therapy agents, and catalysts. The optical, electronic, coordination and structural properties that can be modified for the purposes of Pcs have led to many different applications than traditional uses [1–3]. The biggest obstacle limiting the areas that Pcs can be used is their solubility problems. Substitution at the peripheral and non-peripheral positions with groups like tert-butyl, alkyl, alkoxy, alkylthio, aryloxy chains, macrocyclic, or fluorinated groups increases the solubility of Pcs, since these substituents increase the distance among the stacked Pcs. Solubility of Pcs in common polar and nonpolar solvents permits the application of purification methods and increases the applications and plays a key role in obtaining thin films with various methods [4–17].