Position Of Methoxy Substituent Research Articles

Effects of the number and position of methoxy substituents on triphenylamine-based chalcone visible-light-absorbing photoinitiators

Five visible-light-absorbing triphenylamine-based chalcone photoinitiators (CY1–CY5) have been synthesized for application in free radical photopolymerization.

Acenaphthoquinoxaline Derivatives as Dental Photoinitiators of Acrylates Polymerization.

A series of dyes based on the acenaphthoquinoxaline skeleton was synthesized. Their structure was modified by introducing electron-withdrawing and electron-donating groups, increasing the number of conjugated double bonds and the number and position of nitrogen atoms, as well as the arrangement of aromatic rings (linear or angular). The dyes were investigated as a component in the photoinitiating systems of radical polymerization for a potential application in dentistry. They acted as the primary absorber of visible light and the acceptor of an electron, which was generated from a second component being an electron donor. Thus, the radicals were generated by the photoinduced intermolecular electron transfer (PET) process. Electron donors used differed in the type of heteroatom, i.e., O, S and N and the number and position of methoxy substituents. To test the ability to initiate the polymerization reaction by photoinduced hydrogen atom transfer, we used 2-mercaptobenzoxazole as a co-initiator. The effectiveness of the photoinitiating systems clearly depends on both the modified acenaphthoquinocaline structure and the type of co-initiator. The lower amount of heat released during the chain reaction and the polymerization rate comparable to this achieved for the photoinitiator traditionally used in dentistry (camphorquinone) indicates that the studied dyes may be valuable in this field.

Efficiently luminescent cuprous iodide complexes supported by novel N^P-chelating ligands: Synthesis, structure and optoelectronic performances

Phosphorescent cuprous complexes (1–6) with general formula CuI(N^P) (PPh3), where N^P = 2-(2′-diphenylphosphinophenyl)-1-phenyl-5-methoxybenzimidazole derivatives, have been designed and synthesized. The crystal structures of the neutral four-coordinated Cu(I) complexes are determined by single crystal X-ray diffraction. At 293 K, these complexes exhibit intense phosphorescence with exceptionally high photoluminescence quantum yields (up to 88.3%) and short decay times (4.8–55.2 μs). The emission maxima can be fine-tuned from 529 nm to 577 nm, depending upon the number and position of methoxy substituent on the N^P ligand. Especially, complex 5 exhibits phosphorescence (533 nm) with photoluminescence quantum yield of 70.5% and decay time of 19.5 μs, implying its potential to serve as a phosphor for organic light emitting diode (OLED). Solution-processed OLED incorporating complex 5 as dopant emitter achieves a maximum brightness of 7729 cd with CIE coordinates (0.4351, 0.5398), constituting a step further toward the design of cuprous complexes as cheap and environmental alternatives to the luminescent noble metal complex.

Fe(III)(MeO‐salen)Cl] complexes and their in vitro cytotoxicity against KB and HepG2 human cancer cells

AbstractMethoxy‐substituted iron(III)‐salen complexes ([Fe(III)(MeO‐salen)Cl] with salen = N,N’‐bis(salicylidene)‐1,2‐ethylenediimine) were synthesized and structurally analyzed. Their in vitro cytotoxicity against KB and HepG2 human cancer cells was examined. The obtained results obviously demonstrated the correlation between the cytotoxicity of the complexes and the position of methoxy substituents in the salicylidene moieties as the following; 3‐OCH3 < H ~ 6‐OCH3 < 4‐OCH3 < 5‐OCH3.

Effect of number and position of methoxy substituents on fine-tuning the electronic structures and photophysical properties of designed carbazole-based hole-transporting materials for perovskite solar cells: DFT calculations

In perovskite solar cells (PSCs), the state-of-art Spiro-OMeTAD, which used as a hole-transporting material (HTM), suffered from complicated multistep synthesis and difficult purification that make this material cost ineffective, in addition to it being UV-unstable. Thus, new, cost-effective and easy to synthesize small organic molecules is still required. As reported, a carbazole-based compound (R01) was synthesized using a simple two steps method from low-cost commercially available compounds and used as an HTM. R01 exhibited higher conductivity and hole-mobility compared to that of the Spiro-OMeTAD. PSCs fabricated with R01 produced a power conversion efficiency of 12.03%, equivalent to that obtained in devices where Spiro-OMeTAD was the HTM. These findings highlighted R01 as a highly promising HTM with high performance, facile synthesis, and low cost. From a structural perspective, methoxy groups (–OCH3) in the HTM structure are controlling the HOMO level of the compound, apart from the critical role they play in anchoring the material onto the core perovskite layer. In this paper, we report a systematic study of the electronic structures and photophysical properties of twelve designed derivatives of R01. R01 was modified by substituting some hydrogen in the carbazole rings by two, four and six methoxy groups at different positions. The ground and excited state geometries are optimized by applying density functional theory (DFT) and its time-dependent functional (TDDFT), respectively. Detailed investigation of two factors: (i) the number and (ii) position of methoxy groups on the frontier molecular orbitals (FMOs), absorption and emission wavelengths, ionization potential, electron affinity, reorganization energies and charge mobility are examined and discussed. The electro-optical and nonlinear optical (NLO) properties are finely tuned in the R01 derivatives. By incorporating methoxy substituents into this carbazole-based compound, systematic design of potential materials for PSCs can be feasible.

Investigation of chalcones as selective inhibitors of the breast cancer resistance protein: critical role of methoxylation in both inhibition potency and cytotoxicity.

ABCG2 plays a major role in anticancer-drug efflux and related tumor multidrug resistance. Potent and selective ABCG2 inhibitors with low cytotoxicity were investigated among a series of 44 chalcones and analogues (1,3-diarylpropenones), by evaluating their inhibitory effect on the transport of mitoxantrone, a known ABCG2 substrate. Six compounds producing complete inhibition with IC(50) values below 0.5 μM and high selectivity for ABCG2 were identified. The number and position of methoxy substituents appeared to be critical for both inhibition and cytotoxicity. The best compounds, with potent inhibition and low toxicity, contained an N-methyl-1-indolyl (compound 38) or a 6'-hydroxyl-2',4'-dimethoxy-1-phenyl (compound 27) moiety (A-ring) and two methoxy groups at positions 2 and 6 of the 3-phenyl moiety (B-ring). Methoxy substitution contributed to inhibition at positions 3 and 5, but had a negative effect at position 4. Finally, methoxy groups at positions 3, 4, and 5 of the B-ring markedly increased cytotoxicity and, therefore, should be avoided.

Influence of methoxy groups on the antiproliferative effects of [Fe III(salophene-OMe)Cl] complexes

We synthesized methoxy-substituted iron(III)-salophene complexes ([Fe III(OMe-salophene)Cl] with salophene = N, N′-bis(salicylidene)-1,2-phenylenediamine) and analyzed their biological activity in MCF-7 and MDA-MB-231 breast cancer as well as in HT-29 colon carcinoma cells. The results obtained in a time-dependent chemosensitivity test clearly demonstrated the correlation between the cytotoxicity of the complexes and the position of methoxy substituents in the salicylidene moieties: 3-OCH 3 ( 4) < 5-OCH 3 ( 8) < H ( 2) < 4-OCH 3 ( 6) = 6-OCH 3 ( 10). Compounds 6 and 10 caused cytocidal effects already at a concentration of 0.5 μM. Both lead compound 2 and complex 8 showed similar time response curves, however, with a 5-fold lower activity compared to 6 and 10, respectively. Referring to [Fe III(salophene)Cl] ( 2), methoxy substitution was accompanied with the loss of tumor cell selectivity. Moreover, the free ligands ( 1, 3, 5, 7, and 9) were inactive.

Intermolecular interaction between multifunctional porphyrin and ubiquinone analogues

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