scholarly journals Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

2020 ◽  
Vol 16 ◽  
pp. 2589-2597
Author(s):  
Jannis Ludwig ◽  
Tobias Moje ◽  
Fynn Röhricht ◽  
Rainer Herges
Keyword(s):  
Carboxylic Acid ◽  
High Spin ◽  
Spin State ◽  
Intramolecular Coordination ◽  
Carboxylic Acid Groups ◽  
Molecular Spin ◽  
Switching Efficiency ◽  
Spin Switching

We present the synthesis and the spin switching efficiencies of Ni(II)-porphyrins substituted with azopyridines as covalently attached photoswitchable ligands. The molecules are designed in such a way that the azopyridines coordinate to the Ni ion if the azo unit is in cis configuration. For steric reasons no intramolecular coordination is possible if the azopyridine unit adopts the trans configuration. Photoisomerization of the azo unit between cis and trans is achieved upon irradiation with 505 nm (trans→cis) and 435 nm (cis→trans). Concurrently with the isomerization and coordination/decoordination, the spin state of the Ni ion switches between singlet (low-spin) and triplet (high-spin). Previous studies have shown that the spin switching efficiency is strongly dependent on the solvent and on the substituent at the 4-position of the pyridine unit. We now introduced thiol, disulfide, thioethers, nitrile and carboxylic acid groups and investigated their spin switching efficiency.

scholarly journals Synthesis of 4-substituted azopyridine-functionalized Ni(II) porphyrins as molecular spin switches

2020 ◽  
Author(s):  
Jannis Ludwig ◽  
Tobias Moje ◽  
Fynn Röhricht ◽  
Rainer Herges
Keyword(s):  
Carboxylic Acid ◽  
High Spin ◽  
Spin State ◽  
Intramolecular Coordination ◽  
Carboxylic Acid Groups ◽  
Molecular Spin ◽  
Switching Efficiency ◽  
Spin Switching

We present the synthesis and the spin switching efficiencies of Ni(II)-porphyrins substituted with azopyridines as covalently attached photoswitchable ligands. The molecules are designed in such a way that the azopyridines coordinate to the Ni ion if the azo unit is in cis configuration. For steric reasons no intramolecular coordination is possible if the azopyridine unit adopts the trans configuration. Photoisomerization of the azo unit between cis and trans is achieved upon irradiation with 505 nm (trans→cis) and 435 nm (cis→trans). Concurrently with the isomerization and coordination/decoordination, the spin state of the Ni ion switches between singlet (low-spin) and triplet (high-spin). Previous studies have shown that the spin switching efficiency is strongly dependent on the solvent and on the substituent at the 4-position of the pyridine unit. We now introduced thiol, disulfide, thioethers, nitrile and carboxylic acid groups and investigated their spin switching efficiency.

scholarly journals Grafting TRAIL through Either Amino or Carboxylic Groups onto Maghemite Nanoparticles: Influence on Pro-Apoptotic Efficiency

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 502
Author(s):  
Hanene Belkahla ◽  
Andrei Alexandru Constantinescu ◽  
Tijani Gharbi ◽  
Florent Barbault ◽  
Alexandre Chevillot-Biraud ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Cancer Therapy ◽  
Computational Study ◽  
Carcinoma Cells ◽  
Maghemite Nanoparticles ◽  
Carboxylic Acid Groups ◽  
Lung Carcinoma Cells ◽  
Biological Studies ◽  
Apoptotic Effect ◽  
Carboxylic Groups

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF cytokine superfamily. TRAIL is able to induce apoptosis through engagement of its death receptors DR4 and DR5 in a wide variety of tumor cells while sparing vital normal cells. This makes it a promising agent for cancer therapy. Here, we present two different ways of covalently grafting TRAIL onto maghemite nanoparticles (NPs): (a) by using carboxylic acid groups of the protein to graft it onto maghemite NPs previously functionalized with amino groups, and (b) by using the amino functions of the protein to graft it onto NPs functionalized with carboxylic acid groups. The two resulting nanovectors, NH-TRAIL@NPs-CO and CO-TRAIL@NPs-NH, were thoroughly characterized. Biological studies performed on human breast and lung carcinoma cells (MDA-MB-231 and H1703 cell lines) established these nanovectors are potential agents for cancer therapy. The pro-apoptotic effect is somewhat greater for CO-TRAIL@NPs-NH than NH-TRAIL@NPs-CO, as evidenced by viability studies and apoptosis analysis. A computational study indicated that regardless of whether TRAIL is attached to NPs through an acid or an amino group, DR4 recognition is not affected in either case.

scholarly journals Vacancy tuned thermoelectric properties and high spin filtering performance in graphene/silicene heterostructures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zainab Gholami ◽  
Farhad Khoeini
Keyword(s):  
Electric Fields ◽  
High Spin ◽  
High Efficiency ◽  
Practical Applications ◽  
External Electric Fields ◽  
Ferromagnetic Exchange ◽  
High Spin Polarization ◽  
Filtering Effect ◽  
Spin Switching ◽  
Spin Filtering

AbstractThe main contribution of this paper is to study the spin caloritronic effects in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR is subjected to the ferromagnetic exchange and local external electric fields, and their responses are determined using the nonequilibrium Green’s function (NEGF) approach. To further study the thermoelectric (TE) properties of the GSNRs, three defect arrangements of divacancies (DVs) are also considered for a larger system, and their responses are re-evaluated. The results demonstrate that the defected GSNRs with the DVs can provide an almost perfect thermal spin filtering effect (SFE), and spin switching. A negative differential thermoelectric resistance (NDTR) effect and high spin polarization efficiency (SPE) larger than 99.99% are obtained. The system with the DV defects can show a large spin-dependent Seebeck coefficient, equal to Ss ⁓ 1.2 mV/K, which is relatively large and acceptable. Appropriate thermal and electronic properties of the GSNRs can also be obtained by tuning up the DV orientation in the device region. Accordingly, the step-like GSNRs can be employed to produce high efficiency spin caloritronic devices with various features in practical applications.

Theoretical study on the reduction reactions from solid char(N): The effect of the nearby group and the high-spin state

Energy ◽  
2019 ◽  
Vol 189 ◽  
pp. 116286 ◽  
Author(s):  
Hai Zhang ◽  
Lei Luo ◽  
Jiaxun Liu ◽  
Anyao Jiao ◽  
Jianguo Liu ◽  
...  
Keyword(s):  
High Spin ◽  
Spin State ◽  
Theoretical Study ◽  
High Spin State ◽  
Reduction Reactions

AFM Imaging of Molecular Spin-State Changes through Quantitative Thermomechanical Measurements

2014 ◽  
Vol 26 (18) ◽  
pp. 2889-2893 ◽  
Author(s):  
Edna M. Hernández ◽  
Carlos M. Quintero ◽  
Olena Kraieva ◽  
Christophe Thibault ◽  
Christian Bergaud ◽  
...  
Keyword(s):  
Spin State ◽  
Afm Imaging ◽  
Molecular Spin ◽  
State Changes

Dual-temperature and pH responsive (ethylene glycol)-based nanogels via structural design

2014 ◽  
Vol 5 (8) ◽  
pp. 3061-3070 ◽  
Author(s):  
Yohei Kotsuchibashi ◽  
Ravin Narain
Keyword(s):  
Carboxylic Acid ◽  
Ethylene Glycol ◽  
Salt Concentration ◽  
Structural Design ◽  
Solution Temperature ◽  
Ph Responsive ◽  
Solution Ph ◽  
Critical Solution Temperature ◽  
Carboxylic Acid Groups ◽  
The Core

Dual-temperature and pH responsive (ethylene glycol)-based nanogels were synthesized. Both the core and the shell of the nanogels showed a lower critical solution temperature (LCST) and the LCST of the shell was strongly affected by the solution pH and salt concentration due to the presence of carboxylic acid groups at the nanogel surface.

Metal ion retention properties of water-insoluble polymers containing carboxylic acid groups

2005 ◽  
Vol 99 (3) ◽  
pp. 697-705 ◽  
Author(s):  
Bernabé L. Rivas ◽  
Benita Quilodrán ◽  
Eduardo Quiroz
Keyword(s):  
Carboxylic Acid ◽  
Metal Ion ◽  
Carboxylic Acid Groups ◽  
Insoluble Polymers
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