Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent elec...Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent electron transfer rate constants were calculated depending on the chain length and solvent polarity.展开更多
Benzo[d]thiazol-2-ylmethanol undergoes progressive oligomerization under solvothermal conditions in the presence of FeCl_(3)·6H_(2)O,yielding a heterocyclic aggregate,namely 1,2,3-tris(benzo[d]thiazol-2-yl)-2,9-d...Benzo[d]thiazol-2-ylmethanol undergoes progressive oligomerization under solvothermal conditions in the presence of FeCl_(3)·6H_(2)O,yielding a heterocyclic aggregate,namely 1,2,3-tris(benzo[d]thiazol-2-yl)-2,9-dihydrobenzo[b]cyclopenta[e][1,4]thiazine.Single-crystal X-ray diffraction analysis was conducted on four distinct compounds isolated during the reaction,and electrospray ionization mass spectrometry(ESI-MS)of both solid products and intermediate reaction solutions enabled the identification of 15 consecutive reaction steps,where Fe(Ⅲ)was directly involved in eight steps.These transformations comprise nine intermolecular C─C coupling events and six intramolecular ring expansion processes.The heteroatoms(N,O,and S)play distinct mechanistic roles according to their positions within the heterocyclic framework:(1)nitrogen and oxygen coordinate with Fe(Ⅲ),facilitating activation of the reaction site;(2)homolytic cleavage of the C─O bond promotes C─C coupling reactions;and(3)C─S migration induces intramolecular ring expansion.Notably,theoretical calculations indicate a decrease in Gibbs free energy along the intramolecular reaction pathways,substantiating the proposed mechanism and activation mode,which underscores the essential role of Fe(Ⅲ)in enabling the reaction progression.Furthermore,an investigation of the photophysical properties revealed that the resulting heterocyclic aggregates exhibit strong luminescence within the 535–610 nm wavelength range,approaching the near-infrared region.These findings highlight the significance of this reaction pathway in the controlled synthesis of functional oligomers and polymers from monomeric precursors,particularly through catalysis by cost-effective metal ions.展开更多
A wealth of literature has been published in the studies of Chinese fresh-water fish chromosomes within recent years.In this paper,we review the inter-and intraspecific genetic diversities found in Chinese fresh-water...A wealth of literature has been published in the studies of Chinese fresh-water fish chromosomes within recent years.In this paper,we review the inter-and intraspecific genetic diversities found in Chinese fresh-water fishes,and explore the characteristics and mechanisms that underline these diversities and variations. We also propose the hypothesis how the genetic diversities had evolved in the fresh-water fishes.展开更多
文摘Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent electron transfer rate constants were calculated depending on the chain length and solvent polarity.
文摘Benzo[d]thiazol-2-ylmethanol undergoes progressive oligomerization under solvothermal conditions in the presence of FeCl_(3)·6H_(2)O,yielding a heterocyclic aggregate,namely 1,2,3-tris(benzo[d]thiazol-2-yl)-2,9-dihydrobenzo[b]cyclopenta[e][1,4]thiazine.Single-crystal X-ray diffraction analysis was conducted on four distinct compounds isolated during the reaction,and electrospray ionization mass spectrometry(ESI-MS)of both solid products and intermediate reaction solutions enabled the identification of 15 consecutive reaction steps,where Fe(Ⅲ)was directly involved in eight steps.These transformations comprise nine intermolecular C─C coupling events and six intramolecular ring expansion processes.The heteroatoms(N,O,and S)play distinct mechanistic roles according to their positions within the heterocyclic framework:(1)nitrogen and oxygen coordinate with Fe(Ⅲ),facilitating activation of the reaction site;(2)homolytic cleavage of the C─O bond promotes C─C coupling reactions;and(3)C─S migration induces intramolecular ring expansion.Notably,theoretical calculations indicate a decrease in Gibbs free energy along the intramolecular reaction pathways,substantiating the proposed mechanism and activation mode,which underscores the essential role of Fe(Ⅲ)in enabling the reaction progression.Furthermore,an investigation of the photophysical properties revealed that the resulting heterocyclic aggregates exhibit strong luminescence within the 535–610 nm wavelength range,approaching the near-infrared region.These findings highlight the significance of this reaction pathway in the controlled synthesis of functional oligomers and polymers from monomeric precursors,particularly through catalysis by cost-effective metal ions.
基金State Education Commission Research Foundation for Doctoral Disciplines
文摘A wealth of literature has been published in the studies of Chinese fresh-water fish chromosomes within recent years.In this paper,we review the inter-and intraspecific genetic diversities found in Chinese fresh-water fishes,and explore the characteristics and mechanisms that underline these diversities and variations. We also propose the hypothesis how the genetic diversities had evolved in the fresh-water fishes.
