排序方式: 共有5条查询结果,搜索用时 9 毫秒
1
1.
2.
Rikuhei Tanikaga Takeshi Nishikawa Naoki Tomita 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):455-456
Stereochemistry in alkylations and H-D exchange of configurationally defined α-sulfonyl- and α-sulfinyl-carbanions generated from the compounds I-IV, are discussed. 相似文献
3.
Hitoshi Tamiaki Masaaki Amakawa Yoshiyuki Shimono Rikuhei Tanikaga Alfred R. Holzwarth Kurt Schaffner 《Photochemistry and photobiology》1996,63(1):92-99
Abstract— A comparison of the spectra of in vitro (3-hydroxymethyl-131 -oxometallochlorin) and in vivo chlorosomal (bacterio-chlorophyll- c ) aggregates suggests a similar supramolecular structure for the artificial oligomers and the bacte-riochlorophyll- c aggregates in the extramembranous antenna complexes (chlorosomes) of green photosynthetic bacteria. Synthetic zinc and magnesium chlorins have been found to aggregate in 1 % (vol/vol) tetrahydrofuran and hexane solutions and in thin films to form oligomers with the Qy absorption bands shifted to longer wavelengths by about 1900 (Zn chlorins) and 2100 cm−1 (Mg) relative to the corresponding monomer bands. Visible absorption and circular dichroism spectra of various zinc chlorins establish that a central metal, a 31 -hydroxy and a 131 -keto group are functional prerequisites for the aggregation. Vibrational bands measured by IR spectroscopy of solid films reveal two characteristic structural features of the oligomers: (1) a five-coordinated metallochlorin macrocycle with an axial ligand (bands at 1500-1630 cm−1 ), and (2) a hydrogen bond between the keto oxygen of one chlorin and the hydroxy group of a second chlorin, the oxygen of which is chelated to the metal atom of a third molecule, i.e . C=O…H-O…M (=Zn or Mg). 相似文献
4.
5.
1