Synthesis and properties of a photochromic perinaphthothioindigo conjugated with two porphyrins

2020 ◽  
Vol 24 (08) ◽  
pp. 1030-1037
Author(s):  
Kazuya Ogawa ◽  
Masaki Sato ◽  
Kenta Terao
Keyword(s):  
Absorption Spectra ◽  
Trans Isomer ◽  
Absorption Peak ◽  
Homo Lumo ◽  
Cis Isomer

In this study, we synthesized a new porphyrin-perinaphthothioindigo composite in which two porphyrins are connected to a perinaphthothioindigo dye through ethynyl linkages. The UV-vis absorption spectra of the composite showed an absorption peak originating from the trans-isomer at around 730 nm. Upon photoirradiation at 760 nm, the intensity of this absorption decreased with increasing absorption of the cis-isomer around 500 nm. The HOMO–LUMO absorption of the cis-isomer is blue-shifted by ˜230 nm compared to that of trans-isomer due to lack of [Formula: see text] conjugation. The shift by 230 nm is 100 nm larger than that observed for the monoporphyrin-substituted compound, indicating the expansion of [Formula: see text] conjugation by the additional porphyrin.

Synthesis and photophysical properties of a porphyrin-perinaphthothioindigo dye

2013 ◽  
Vol 17 (08n09) ◽  
pp. 821-830 ◽  
Author(s):  
Kazuya Ogawa ◽  
Joanne Dy ◽  
Rena Maeda ◽  
Yasunori Nagatsuka ◽  
Kenji Kamada ◽  
...  
Keyword(s):  
Cross Section ◽  
Trans Isomer ◽  
Triple Bond ◽  
Photophysical Properties ◽  
Reference Compound ◽  
Photochromic Compounds ◽  
Two Photon ◽  
Enhancement Factors ◽  
Homo Lumo ◽  
Cis Isomer

A new porphyrin-perinaphthothioindigo composite, where porphyrin and perinaphthothioindigo dye are connected though a triple bond, was synthesized. In UV-vis absorption spectra of the composite, absorption originating from the trans-isomer appeared at 655 nm. Upon photoirradiation at > 700 nm, the intensity of this absorption decreased with increase of absorption of the cis-isomer around at 530 nm. The HOMO–LUMO absorption of the cis-isomer is blue-shifted by 125 nm compared to that of trans-isomer due to the lack of π-conjugation. The 2PA cross-section values obtained for both isomers were 2,000 and 700 GM, respectively. The value of 2,000 GM is of the largest class among the values reported for photochromic compounds. The enhancement factors by the connection of porphyrin to perinaphthothioindigo were found to be 3.5–3.9 by measuring cross-section values of bis(TMS-ethynyl)perinaphthothioindigo as the reference compound. Two-photon isomerization of the trans-isomer to the cis-isomer was successfully conducted using femtosecond pulses.

scholarly journals Reaction of cis- and trans-Dichlorotetra(Dimethylsulfoxide)Ruthenium(II) With the Antiviral Drug Acyclovir

2000 ◽  
Vol 7 (6) ◽  
pp. 325-334 ◽  
Author(s):  
Aglaia Koutsodimou ◽  
Giovanni Natile
Keyword(s):  
Trans Isomer ◽  
Early Stage ◽  
Antiviral Drug ◽  
Metallic Substrate ◽  
Purine Base ◽  
Coordination Environment ◽  
Molar Ratios ◽  
Discrete Amount ◽  
Cis And Trans ◽  
Cis Isomer

NMR was used to investigate the reaction of cis- and trans-[RuCl2(DMSO)4] with the antiviral drug acyclovir, a guanine derivative containing the acyclic (2-hydroxo) ethoxymethyl pendant linked to N(9). Studies were performed in aqueous solutions at ambient temperature and at 37 °C, and at various molar ratios. Both isomers yielded two compounds, a monoadduct and a bisadduct, the relative yields being dependent upon the metal to ligand concentration ratios. The products derived from the two Ru isomers displayed identical NMR spectra, suggesting that they have the same coordination environment, however the rate of formation of the monoadduct was higher in the case of the trans isomer than in the case of the cis isomer, while the rate of conversion of the monoadduct into the bisadduct appeared to be similar in both cases. As a consequence in the case of the trans isomer there is accumulation of monoadduct in the early stage of the reaction, whose concentration afterwards decreases with the progress of the reaction. As for platinum, also for ruthenium the preferred binding site is N(7) of the purine base, however, in the case of ruthenium a discrete amount of bisadduct is formed even in the presence of an excess of metallic substrate with respect to the acyclovir ligand; under similar conditions a platinum substrate would have given, nearly exclusively, the monoadduct.

scholarly journals Effects of Aromatic Thiol Capping Agents on the Structural and Electronic Properties of CdnTen (n = 6,8 and 9) Quantum Dots

2021 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Imran ◽  
Muhammad Jawwad Saif ◽  
Tahir Farooq ◽  
Javed Iqbal
Keyword(s):  
Quantum Dots ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Capping Agents ◽  
Aromatic Thiol ◽  
Td Dft ◽  
Structural And Electronic Properties ◽  
Aromatic Thiols ◽  
Capping Ligands ◽  
Homo Lumo

Thiols are efficient capping agents used for the synthesis of semiconductor and metal nanoparticles. Commonly, long-chain thiols are used as passivating agents to provide stabilization to nanoparticles. Theoretical methods rarely reported aromatic thiol ligands’ effects on small-sized CdTe quantum dots’ structural and electronic properties. We have studied and compared the structural and electronic properties of (i) bare and (ii) aromatic thiols (thiophenol, 4-methoxybenzenethiol, 4-mercaptobenzonitrile, and 4-mercaptobenzoic acid) capped CdnTen quantum dots (QDs). Aromatic thiols are used as thiol-radical because of the higher tendency of thiol-radicals to bind with Cd atoms. This work provides an understanding of how the capping agents affect specific properties. The results show that all aromatic thiol-radical ligands caused significant structural distortion in the geometries. The aromatic thiol-radical ligands stabilize LUMOs, stabilize or destabilize HOMOs, and decrease HOMO-LUMO gaps for all the capped QDs. The stabilization of LUMOs is more pronounced than the destabilization of HOMOs. We also studied the effect of solvent on structural and electronic properties. TD-DFT calculations were performed to calculate the absorption spectra of bare and capped QDs, and all the capping ligands resulted in the redshift of absorption spectra.

[1H,15N] N.M.R. Kinetic Studies of Reactions of cis- and trans-[PtCl2(15NH3)(c-C6H1115NH2)] with Guanosine 5'-Monophosphate

1999 ◽  
Vol 52 (3) ◽  
pp. 173 ◽  
Author(s):  
Sarah J. Barton ◽  
Kevin J. Barnham ◽  
Abraha Habtemariam ◽  
Urban Frey ◽  
Rodney E. Sue ◽  
...  
Keyword(s):  
Trans Isomer ◽  
Active Metabolite ◽  
Kinetic Studies ◽  
Trans Influence ◽  
Trans Complex ◽  
Kinetics Of Reaction ◽  
Cis And Trans ◽  
Kinetics Of ◽  
Cis Isomer ◽  
Amine Ligand

cis-[PtCl2(15NH3)(c-C6H11NH2)] is an active metabolite of the oral platinum(IV) anticancer drug cis,trans,cis-[PtCl2(CH3CO2)2(NH2)(c-C6H11NH2)]. Since it is likely that guanine bases on DNA are targets for this drug, we have analysed the kinetics of reaction of this platinum(II) metabolite with guanosine 5′-monophosphate (5′-GMP) at 310 K, pH 7, using [1H, 15N] n.m.r. methods. Reactions of the trans isomer are reported for comparison. The reactions proceed via aquated intermediates, and, for the cis isomer, the rates of aquation and substitution of H2O by 5′-GMP are 2-5 times faster trans to the amine ligand (c-C6H11NH2) compared to trans to NH3 for both the first and second steps. For the trans complex, the first aquation step is c. 3 times faster than for the cis complex, as expected from the higher trans influence of Cl¯, whereas the rate of the second aquation step (trans to N7 of 5′-GMP) is comparable to that trans to NH3. These findings have implications for the courses of reactions with DNA.

FORMATION OF Te NANOWIRES IN ZEOLITE AFI AND THEIR POLARIZED ABSORPTION SPECTRA

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2817-2822 ◽  
Author(s):  
SHUN-ICHI INOUE ◽  
NAOTO KOSHIZAKI ◽  
TETSUYA KODAIRA
Keyword(s):  
Raman Scattering ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Spectral Shape ◽  
Absorption Peak ◽  
High Loading ◽  
One Dimensional ◽  
Anisotropic Properties ◽  
Scattering Spectra ◽  
Raman Scattering Spectra

Te atoms were loaded into nanochannels of zeolite AFI single crystals. The polarized absorption and Raman scattering spectra were measured. The absorption spectra of Te loaded AFI showed large anisotropic properties. The absorption spectra of E//c deeply depended on the loading density of Te atoms. In low Te loading density, Te was adsorbed into the nanochannels in a dimer form whose absorption peak appeared at ca. 3.5 eV . In high loading density, Te form one dimensional nanowires inside the channels. Nanowire formation causes large anisotropic absorption and changes in the spectral shape.

Sur la réduction de polyméthyldihydro-2,3 phénalènones-1 par l'hydrure de lithium et d'aluminium

1974 ◽  
Vol 52 (17) ◽  
pp. 3106-3112 ◽  
Author(s):  
E. Costakis ◽  
P. Canonne ◽  
R. St-Jean
Keyword(s):  
Trans Isomer ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Considerable Extent ◽  
Lithium Aluminum ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Cis Isomer ◽  
Steric Constraints

The reduction of some polymethyl-2,3-dihydro phenalen-1-ones by lithium aluminum hydride yields a mixture of cis and trans isomers; the percentage of each isomer depends to a considerable extent on its structure. Indeed, for some, the trans isomer predominates while for others the cis isomer is obtained in up to 88% yields. Moreover, in the particular case in which the trans isomer is formed in low yields, its preferred conformation is trans diaxial.The steric constraints which render certain transition states unfavourable during the attack of the hydride are discussed with the aid of spectroscopic data on the alcohols obtained. [Journal translation]

The importance of conformation in the reactivity of radical cations. Changing configuration at saturated carbon centres

1992 ◽  
Vol 70 (1) ◽  
pp. 272-279 ◽  
Author(s):  
Allyson L. Perrott ◽  
Donald R. Arnold
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Molecular Mechanics ◽  
Radical Cation ◽  
Trans Isomer ◽  
Radical Cations ◽  
Singlet Excited State ◽  
Photostationary State ◽  
Configurational Isomerization ◽  
Cis Isomer

Irradiation of an acetonitrile solution of cis 1-methyl-2-phenylcyclopentane (1bcis); 1,4-dicyanobenzene (2), an electron-accepting photosensitizer; and 2,4,6-collidine (3), a nonnucleophilic base, leads to configurational isomerization of the cyclopentane; the photostationary state lies > 99% in favour of the trans isomer. The mechanism proposed for this reaction involves formation of the radical cation of 1bcis by photoinduced electron transfer to the singlet excited state of 2, deprotonation of the radical cation assisted by the base 3, reduction of the resulting benzylic radical by the radical anion [Formula: see text], and reprotonation of the benzylic anion to give both the cis and the trans isomers of 1b. The photostationary state is controlled by the relative rates of deprotonation of the radical cations of 1bcis and trans; these rates are dependent upon the extent of overlap of the SOMO of the radical cation, which is largely associated with the phenyl ring, and the benzylic carbon–hydrogen bond. Molecular mechanics calculations (MM3 and MMP2) are used to calculate the preferred conformations of the isomers. The required orbital overlap is 31% effective with the global minimum conformation of the cis isomer and essentially ineffective for the low-lying conformations of the trans isomer. This proposed mechanism is supported by Stem–Volmer quenching studies, which indicate that both isomers quench the singlet excited state of 2 at the diffusion-controlled rate, and by deuterium incorporation studies. When irradiation of the cis isomer is carried out in acetonitrile–methanol-O-d as solvent, isomerization is accompanied by deuterium exchange at the benzylic position; the trans isomer is stable under these conditions. Keywords: photosensitized electron transfer, radical cation, deprotonation, configurational isomerization, conformation, molecular mechanics (MM3).

Synthèse, structure et études spectroscopiques RMN 1H et 13C de dérivés perhydrocyclododéca[b]furaniques

1991 ◽  
Vol 69 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Michel Albrand ◽  
René Dolmazon ◽  
Patrick Pollet
Keyword(s):  
Conformational Analysis ◽  
Force Field ◽  
Key Words ◽  
Molecular Mechanics ◽  
Trans Isomer ◽  
Nmr Spectra ◽  
Synthetic Route ◽  
Force Field Calculations ◽  
Cis Isomer ◽  
C Nmr

A synthetic route to perhydrocyclododeca[b]furan-3-ols, perhydrocyclododeca[b]furan-3-ones, and perhydrocyclododeca[b]furan derivatives is described. Their configurations were determined. For the perhydrocyclododeca[b]furan-3-one and perhydrocyclododeca[b]furan pairs, the cis isomer was much less stable than the trans isomer. This agrees well with results from a conformational analysis, carried out by molecular mechanics. The 1H and l3C NMR spectra are reported. Key words: perhydrocyclododeca[b]furans, conformations, force field calculations, 1H and 13C NMR.

Quantum Yield and Curing Velocity of Two α-Hydroxy Ketone Photoinitiators

2013 ◽  
Vol 721 ◽  
pp. 233-236
Author(s):  
Peng Li
Keyword(s):  
Quantum Yield ◽  
Absorption Spectra ◽  
Spectroscopic Analysis ◽  
Absorption Peak ◽  
Quantum Yields ◽  
Hydroxy Ketone ◽  
Mass Percentage ◽  
The Relationship

The quantum yield is an important parameter to evaluate the initiation efficiency of photoinitiators and improve the curing velocity of photocurable materials. In this paper, two α-hydroxy ketone photoinitiators (Darocure1173 and Irgacure184) were studied based on the spectroscopic analysis and photo-initiated theory. Exposure fore-and-aft absorption spectra of samples with different exposure thickness (5mm, 10mm, 15mm, 20mm and 25mm) were measured. Quantum yields were obtained by analyzing the relationship between the exposure thickness and evaluation error. The curing velocity related to different photoinitiator and photoinitiator mass percentage was studied. Results show that quantum yields of Darocure1173 and Irgacure184 are 0.277% and 0.207% respectively at absorption peak (247nm). Optimal proportions of two photoinitiators are 6% and 5% respectively. Darocure1173 is prior to Irgacure184 in curing velocity.

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