title: Synthesis of a novel hypocrellin B derivative and its photogeneration of semiquinone anion radical.
abstract: In order to improve the photosensitizing activity of HB further, the complex of 5,8-di-Br-HB with Al(3+) was first designed and synthesized in high yield. 5,8-di-Br-HB forms a 2:1 type (metal-ligand ratio) complex with Al(3+) measured by molar ratio and continuous variation methods. The new photosensitizer was characterized by UV-Vis, IR, 1H NMR and elemental analysis measurements. Based on the above experimental results, we first proposed a polymer-like structural model of the complex. The water-solubility and red absorption of the [Al(2)(5,8-di-Br-HB)Cl(4)](n) complex are both enhanced over hypocrellin B. In addition, the EPR and spectrophotometric measurements demonstrate that semiquinone anion radical of [Al(2)(5,8-di-Br-HB)Cl(4)](n) can be produced by [Al(2)(5,8-di-Br-HB)Cl(4)](n) photosensitization. The generation efficiency of ([Al(2)(5,8-di-Br-HB)Cl(4)](n))(.-) is almost equal to that of HB(.-). These results obtained indicated that [Al(2)(5,8-di-Br-HB)Cl(4)](n)was at least a favorable Type I phototherapeutic agent.
authors.affiliation: Center for Molecular Science, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: J H
authors.initials: JH
authors.lastname: Ma
authors.forename: J Q
authors.initials: JQ
authors.lastname: Zhao
authors.forename: L J
authors.initials: LJ
authors.lastname: Jiang
mesh_terms: D000535:Aluminum; D017607:Aluminum Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D016227:Benzoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010569:Perylene / Q000031:analogs & derivatives*; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry; D011809:Quinones / Q000138:chemical synthesis* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: C442579:Al2(5,8-di-Br-HB)Cl4; D017607:Aluminum Compounds; D016227:Benzoquinones; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D011809:Quinones; C025232:semiquinone radicals; D010569:Perylene; D000535:Aluminum; C064522:hypocrellin B