title: Porphyrin-appended europium(III) bis(phthalocyaninato) complexes: synthesis, characterization, and photophysical properties.
abstract: Mixed cyclization of 3-mono-, 4-mono-, or 4,5-di(porphyrinated) phthalonitrile compounds 2, 3, or 6 and unsubstituted phthalonitrile with the half-sandwich complex [EuIII(acac)(Pc)] (Pc=phthalocyaninate, acac=acetylacetonate) as the template in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol afforded novel porphyrin-appended europium(III) bis(phthalocyaninato) complexes 7-9 in 30-40% yield. These mixed tetrapyrrole triads and tetrad were spectroscopically and electrochemically characterized and their photophysical properties were also investigated with steady-state and transient spectroscopic methods. It has been found that the fluorescence of the porphyrin moiety is quenched effectively by the double-decker unit through an intramolecular photoinduced electron-transfer process, which takes place in several hundred femtoseconds, while the recombination of the charge-separated state occurs in several picoseconds. By using different phthalocyanines containing different numbers of porphyrin substituents at the peripheral or nonperipheral position(s) of the ligand, while the other unsubstituted phthalocyanine remains unchanged in these double-deckers, the effects of the number and the position of the porphyrin substituents on these photophysical processes were also examined.
authors.affiliation: Department of Chemistry, Shandong University, Jinan 250100, China.
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Bian
authors.forename: Xinghai
authors.initials: X
authors.lastname: Chen
authors.forename: Dongying
authors.initials: D
authors.lastname: Wang
authors.forename: Chi-Fung
authors.initials: CF
authors.lastname: Choi
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Peihua
authors.initials: P
authors.lastname: Zhu
authors.forename: Dennis K P
authors.initials: DK
authors.lastname: Ng
authors.forename: Jianzhuang
authors.initials: J
authors.lastname: Jiang
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Weng
authors.forename: Xiyou
authors.initials: X
authors.lastname: Li
mesh_terms: D005063:Europium / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D015394:Molecular Structure; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D007211:Indoles; D054833:Isoindoles; D011166:Porphyrins; D005063:Europium; C013647:phthalocyanine