The first fluorine-substituted hexabenzocoronene has been synthesized and its electronic structure and optical properties have been reported [Q. Zhang, et al., Org. Lett. 7 （2005） 5019]. In this letter, the electron...The first fluorine-substituted hexabenzocoronene has been synthesized and its electronic structure and optical properties have been reported [Q. Zhang, et al., Org. Lett. 7 （2005） 5019]. In this letter, the electronic structure and excited state properties of the fluorine-substituted hexabenzocoronene are studied with quantum chemistry method as well as the transition and the charge difference densities. The transition densities show the orientations and strength of the dipole moments and the charge difference densities reveal the orientation and results of the intramolecular charge transfer. The calculated transition energies and oscillator strengths are consistent with the experimental data, and the theoretical results of transition and charge difference densities are valuable to understanding the excited state properties of the fluorine-substituted hexabenzocoronene.展开更多
The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass(BAG),hydroxyapatite(HA)and fluorine substituted hydro...The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass(BAG),hydroxyapatite(HA)and fluorine substituted hydroxyapatite(FHA)nanoparticles.The synthesized powders were incorporated at 10%and 20%into the epoxy-based dental sealer.The setting time,flow and solubility and microhardness of the modified and unmodified samples were examined.The bioactivity was evaluated using FESEM-EDX and elemental mapping,ATR-FTIR and XRD.The flow value of all of the experimental groups except the FHA modified samples,was greater than 20 mm.Concerning solubility,no specimens exhibited more than 1%weight loss.The solubility value of the FHA groups was statistically significant lower than other groups(p≤0.001).The mean hardness values of all of the modified samples were significantly higher than the unmodified group(p≤0.001).Regarding bioactivity,in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles.Based on these results,the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers.Additionally,they improved the in vitro bioactivity of the epoxy sealer.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10374040. The authors thank Dr. Meng-Tao Sun （Department of Chemical Physics, Lund University, Sweden） for stimulating discussions.
文摘The first fluorine-substituted hexabenzocoronene has been synthesized and its electronic structure and optical properties have been reported [Q. Zhang, et al., Org. Lett. 7 （2005） 5019]. In this letter, the electronic structure and excited state properties of the fluorine-substituted hexabenzocoronene are studied with quantum chemistry method as well as the transition and the charge difference densities. The transition densities show the orientations and strength of the dipole moments and the charge difference densities reveal the orientation and results of the intramolecular charge transfer. The calculated transition energies and oscillator strengths are consistent with the experimental data, and the theoretical results of transition and charge difference densities are valuable to understanding the excited state properties of the fluorine-substituted hexabenzocoronene.
基金supported by International Campus of Tehran University of Medical Sciences(IC-TUMS)and health Services grant No.9423684001.
文摘The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass(BAG),hydroxyapatite(HA)and fluorine substituted hydroxyapatite(FHA)nanoparticles.The synthesized powders were incorporated at 10%and 20%into the epoxy-based dental sealer.The setting time,flow and solubility and microhardness of the modified and unmodified samples were examined.The bioactivity was evaluated using FESEM-EDX and elemental mapping,ATR-FTIR and XRD.The flow value of all of the experimental groups except the FHA modified samples,was greater than 20 mm.Concerning solubility,no specimens exhibited more than 1%weight loss.The solubility value of the FHA groups was statistically significant lower than other groups(p≤0.001).The mean hardness values of all of the modified samples were significantly higher than the unmodified group(p≤0.001).Regarding bioactivity,in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles.Based on these results,the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers.Additionally,they improved the in vitro bioactivity of the epoxy sealer.
