55080-55-2Relevant articles and documents
Azomethine phthalimides fluorescent E→Z photoswitches
Georgiev, Anton,Yordanov, Dancho,Dimov, Deyan,Zhivkov, Ivailo,Nazarova, Dimana,Weiter, Martin
, (2020)
Herein, we report the synthesis and E→Z photoswitching behavior of two 4-substituted azomethine phthalimides containing anthracenyl and 4-(dimethylamino)phenyl moieties (EAMP1 and EAMP2). These compounds represent newly synthesized and unstudied photoswitches with dual fluorescence properties as E-isomers and at photostationary state (PSS) depending on the solvent polarity. Steady-state fluorescence measurements were performed in various solvents and the results show strong sensitivity on the environmental polarity. The kinetics of E→Z photoswitching to PSS was studied in AcCN by visible light activation at 410 nm (EAMP1) and long wavelength UV-light activation at 350 nm (EAMP2). The quantitative and qualitative performance of the switching behavior was evaluated by the degree of photoisomerization (R) and the rate constant (k). It was found for EAMP1 R = 6.95 %, k = 8.87 × 10?4 s?1 and EAMP2 R = 88.72 %, k = 4.00 × 10?4 s?1, respectively. The reason for the lower photoconversion of EAMP1 compared to the EAMP2 was analyzed through optimization of the molecular geometry of E- and Z-isomers in the ground state (S0) and first excited state (S1) by DFT/TD-DFT calculations with B3LYP/6-31+G(d,p) level of theory using IEFPCM in AcCN. It was found that E-isomers in the S0 have nonplanar conformation, while the Z-isomer of EAMP1 prefers twisted conformation and the Z-isomer of EAMP2 T-shaped conformation is energetically advantageous compared to the twisted one. The reason is the weak H….π noncovalent interaction (NCI) between 4-(dimethylamino)phenyl moiety and phthalimide ring. Moreover, the Z-isomer of EAMP2 is unusual stable up to 600 min at room temperature in dark compared to the EAMP1, which undergoes full Z→E relaxation for less than 60 min at the same conditions. The Z→E relaxation of EAMP2 is achieved for 90 min at 60 °C. The fluorescence E→Z switching behavior was studied by emission measurements in AcCN and 1,4-DOX as E-isomers and at PSS in room and liquid nitrogen (77 K) temperatures. In the polar and nonpolar solvents, red-shifted emissions with increased fluorescence quantum (Φfl) yields have been observed at PSS compared to the E-isomers. The molecular rotor behavior was studied in the binary mixture of glycerol:ethanol and the results show a sensitivity of the emission bands depending on the environmental viscosity. Time-resolved fluorescence decay measurements were performed in AcCN and 1,4-DOX as E-isomers and at PSS to estimate the mechanism of fundamental fluorescence bands. We found that dyes at PSS have longer lifetime (τ) compared to the E-isomers, especially in less polar 1,4-DOX.
Synthesis of phthalimide disperse dyes and study on the interaction energy
Zhan, Yizhen,Zhao, Xue,Wang, Wei
, p. 240 - 250 (2017)
Three azo dyes had been synthesized using N-ethyl substituted, dibromo-substituted and dicyano-substituted phthalimides as diazo components. All of the synthesized intermediates and dyes have been characterized by MS, 1H NMR, IR and elemental analyses. The dyeing behavior and fastness properties of these dyes have been investigated. Modeling the interaction energy of benzene-benzene, phthalimide-benzene and phthalimide-phthalimide rings, molecule optimization and the interaction energy researching have been done with density functional theory ωB97XD, 6-311G++(d,p) basis set. The results showed that: phthalimide molecule has better coplanarity. Molecule energy of benzene-benzene, phthalimide-benzene and phthalimide-phthalimide rings decreased first and then increased with the increase of the distance between the rings, the lowest energy happened when the distance was about 3.5 ?. Electrostatic force affected the interaction energy most. Substituent groups mainly altered the dispersion force and reduced the energy of the system. The optimization interaction energy of phthalimide-phthalimide, phthalimide-benzene and benzene-benzene was ?47.78 kJ/mol, ?34.66 kJ/mol and ?17.59 kJ/mol. Substituted dibromo group reduced the dipole interaction of the dye.
New insight into probe-location dependent polarity and hydration at lipid/water interfaces: Comparison between gel- and fluid-phases of lipid bilayers
Singh, Moirangthem Kiran,Shweta, Him,Khan, Mohammad Firoz,Sen, Sobhan
, p. 24185 - 24197 (2016)
Environment polarity and hydration at lipid/water interfaces play important roles in membrane biology, which are investigated here using a new homologous series of 4-aminophthalimide-based fluorescent molecules (4AP-Cn; n = 2-10, 12) having different lipophilicities (octanol/water partition coefficient-log-P). We show that 4AP-Cn molecules probe a peculiar stepwise polarity (ENT) profile at the lipid/water interface of the gel-phase (Lβ′) DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) bilayer at room temperature, which was not anticipated in earlier studies. However, the same molecules probe only a subtle but continuous polarity change at the interface of water and the fluid-phase (Lα) DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) bilayer at room temperature. Fluorescence quenching experiments indicate that solutes with different log-P values adsorb at different depths across DPPC/water and DOPC/water interfaces, which correlate with the polarity profiles observed at the interfaces. Molecular dynamics simulations performed on eight probe-lipid systems (four in each of the DPPC and DOPC bilayers-a total run of 2.6 μs) support experimental results, providing further information on the relative position and angle distributions as well as hydration of probes at the interfaces. Simulation results indicate that besides positions, probe orientations also play an important role in defining the local dielectric environment by controlling the probes' exposure to water at the interfaces especially of the gel-phase DPPC bilayer. The results suggest that 4AP-Cn probes are well suited for studying solvation properties at lipid/water interfaces of gel- and fluid-phases simultaneously.
