有机室温磷光(room temperature phosphorescence,RTP)材料凭借制备简单、类型丰富、毒性低等特点,以及在显示、传感、生物成像等方面广阔的应用前景而备受关注.一般的有机RTP材料,其磷光寿命<10 ms,而具有长寿命(τ>100 ms)有机...有机室温磷光(room temperature phosphorescence,RTP)材料凭借制备简单、类型丰富、毒性低等特点,以及在显示、传感、生物成像等方面广阔的应用前景而备受关注.一般的有机RTP材料,其磷光寿命<10 ms,而具有长寿命(τ>100 ms)有机RTP材料其磷光衰减过程裸眼可见,因而具有更广阔的应用前景.本文总结了近年来兼具高效率和长寿命有机RTP材料的分子设计策略,包括引入重原子、形成主-客体材料、构筑H聚集、形成氢键和设计成DonorAcceptor(D-A)结构.展开更多
DNA photocleavage properties of halogenated mono-hydroxyl corrole 1-5 were investigated.It was found that these corroles were able to photocleavage supercoiled pBR 322 DNA（SC） into nicked-circular DNA（NC）.The acti...DNA photocleavage properties of halogenated mono-hydroxyl corrole 1-5 were investigated.It was found that these corroles were able to photocleavage supercoiled pBR 322 DNA（SC） into nicked-circular DNA（NC）.The activity of these corroles follows an order of 4>3>2≈1>5.The photosensitized singlet oxygen（Φ;） quantum yield by these corroles also follows that same order,showing the photocleavage activity is related to the heavy atom effect of halogen atoms on corroles.展开更多
The first step of phasing in any de novo protein structure determination using isomorphous replacement （IR） or anomalous scattering （AD） experiments is to find heavy atom positions. Traditionally, heavy atom posit...The first step of phasing in any de novo protein structure determination using isomorphous replacement （IR） or anomalous scattering （AD） experiments is to find heavy atom positions. Traditionally, heavy atom positions can be solved by inspecting the difference Patterson maps. Due to the weak signals in isomorphous or anomalous differences and the noisy background in the Patterson map, the search for heavy atoms may become difficult. Here, the direct demodulation （DD） method is applied to the difference Patterson maps to reduce the noisy backgrounds and sharpen the signal peaks. The real space Patterson search by using these optimized maps can locate the heavy atom positions more accurately. It is anticipated that the direct demodulation method can assist in heavy atom position determination and facilitate the de novo structure determination of proteins.展开更多
The first hyperpolarizabilities of four squaric acid homologues: squaric acid, 1, 2-dithiosquaric acid, 1, 2-diselenosquaric acid and 1,2-ditellurosquaric acid have been calculated using ab initio and DFT methods. The...The first hyperpolarizabilities of four squaric acid homologues: squaric acid, 1, 2-dithiosquaric acid, 1, 2-diselenosquaric acid and 1,2-ditellurosquaric acid have been calculated using ab initio and DFT methods. The effects of equilibrium geometries. basis set and electron correlation on the first hyperpolarizabilities of these molecules were investigated. The frequency dispersion effect and solvent effect, which are essential to get reliable outputs in comparison to the experimental results, have also been explored. On the basis of these investigations, it is worthy to point out that the heavy atom effect takes effect for these squaric acid homologues.展开更多
A series of symmetrical and unsymmetrical phenylene-vinylene （PV） based chro- mophores with the molecular configuration of donor-π-donor （D-g-D） were prepared and characterized. Iodine was first introduced into t...A series of symmetrical and unsymmetrical phenylene-vinylene （PV） based chro- mophores with the molecular configuration of donor-π-donor （D-g-D） were prepared and characterized. Iodine was first introduced into the Jr-conjugation backbone of the PV based chromophores in order to study the heavy atom effect on their linear absorption, two-photon absorption （TPA） properties, as well as singlet oxygen generation properties. TPA cross-sections of these chromophores were investigated by using the two-photon excited fluorescence method. The unsymmetrical chromophores were found to have larger TPA cross-section values compared to their symmetrical counterparts. For one of the unsymmetrical chromophores with the iodine incorporation, a large TPA cross section value with quenched emission was found. The decreased fluorescence quantum yield of a molecule can be ascribed to the increased intersystem crossing, which is favorable for enhancing the singlet oxygen generation. Therefore, the unsymmetrical PV based chromophores with heavy atom incorporation are promising singlet oxygen sensitizers for the photodynamic therapy application.展开更多
文摘有机室温磷光(room temperature phosphorescence,RTP)材料凭借制备简单、类型丰富、毒性低等特点,以及在显示、传感、生物成像等方面广阔的应用前景而备受关注.一般的有机RTP材料,其磷光寿命<10 ms,而具有长寿命(τ>100 ms)有机RTP材料其磷光衰减过程裸眼可见,因而具有更广阔的应用前景.本文总结了近年来兼具高效率和长寿命有机RTP材料的分子设计策略,包括引入重原子、形成主-客体材料、构筑H聚集、形成氢键和设计成DonorAcceptor(D-A)结构.
基金supported by the National Natural Science Foundation of China(Nos.20771039,20625205, 20871122,20971046)National Key Foundation Research Development Project(973) Item of China(No. 2007CB815306)
文摘DNA photocleavage properties of halogenated mono-hydroxyl corrole 1-5 were investigated.It was found that these corroles were able to photocleavage supercoiled pBR 322 DNA（SC） into nicked-circular DNA（NC）.The activity of these corroles follows an order of 4>3>2≈1>5.The photosensitized singlet oxygen（Φ;） quantum yield by these corroles also follows that same order,showing the photocleavage activity is related to the heavy atom effect of halogen atoms on corroles.
基金Supported by National Natural Science Foundation of China(10979005)National Basic Research Program of China(2009CB918600)
文摘The first step of phasing in any de novo protein structure determination using isomorphous replacement （IR） or anomalous scattering （AD） experiments is to find heavy atom positions. Traditionally, heavy atom positions can be solved by inspecting the difference Patterson maps. Due to the weak signals in isomorphous or anomalous differences and the noisy background in the Patterson map, the search for heavy atoms may become difficult. Here, the direct demodulation （DD） method is applied to the difference Patterson maps to reduce the noisy backgrounds and sharpen the signal peaks. The real space Patterson search by using these optimized maps can locate the heavy atom positions more accurately. It is anticipated that the direct demodulation method can assist in heavy atom position determination and facilitate the de novo structure determination of proteins.
文摘The first hyperpolarizabilities of four squaric acid homologues: squaric acid, 1, 2-dithiosquaric acid, 1, 2-diselenosquaric acid and 1,2-ditellurosquaric acid have been calculated using ab initio and DFT methods. The effects of equilibrium geometries. basis set and electron correlation on the first hyperpolarizabilities of these molecules were investigated. The frequency dispersion effect and solvent effect, which are essential to get reliable outputs in comparison to the experimental results, have also been explored. On the basis of these investigations, it is worthy to point out that the heavy atom effect takes effect for these squaric acid homologues.
基金National Natural Science Foundation of China(21102144)in part supported by 100 Talents Programme of Chinese Academy of Sciences
文摘A series of symmetrical and unsymmetrical phenylene-vinylene （PV） based chro- mophores with the molecular configuration of donor-π-donor （D-g-D） were prepared and characterized. Iodine was first introduced into the Jr-conjugation backbone of the PV based chromophores in order to study the heavy atom effect on their linear absorption, two-photon absorption （TPA） properties, as well as singlet oxygen generation properties. TPA cross-sections of these chromophores were investigated by using the two-photon excited fluorescence method. The unsymmetrical chromophores were found to have larger TPA cross-section values compared to their symmetrical counterparts. For one of the unsymmetrical chromophores with the iodine incorporation, a large TPA cross section value with quenched emission was found. The decreased fluorescence quantum yield of a molecule can be ascribed to the increased intersystem crossing, which is favorable for enhancing the singlet oxygen generation. Therefore, the unsymmetrical PV based chromophores with heavy atom incorporation are promising singlet oxygen sensitizers for the photodynamic therapy application.
