Molina Desiré, El-Khouly Mohamed E, El-Kemary Maged, Fukuzumi Shunichi, Fernández-Lázaro Fernando, Sastre-Santos Ángela
División de Química Orgánica, Instituto de Bioingeniería, Universidad Miguel Hernández, Avda. de la Universidad, s/n, Elche, 03202, Spain.
Department of Chemistry, Faculty of Science, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.
Chemistry. 2016 Dec 5;22(49):17800-17807. doi: 10.1002/chem.201603788. Epub 2016 Oct 31.
A new family of light-harvesting zinc phthalocyanine (ZnPc)-diketopyrrolopyrrole (DPP) hybrids have been synthesized and characterized. The absorption spectral measurements showed that the major absorptions of DPP (450-600 nm) are complementary to those of zinc phthalocyanine (300-400 and 600-700 nm). Therefore, the designed hybrids absorb over a broad range in the visible region. The geometric and electronic structures of the dyads were probed by initio B3LYP/6-311G methods. The majority of the HOMOs were found to be located on the ZnPc, while the majority of the LUMOs were on the DPP units. The DPP units serve as the antenna, which upon excitation undergo efficient singlet-singlet energy transfer to the attached ZnPc units. The formed singlet ZnPc, in turn, donates its electron to the electron-deficient DPP forming the low-lying radical ion pairs ZnPc -DPP (energy=1.44-1.56 eV as calculated from the electrochemical measurements). The excited-state events were confirmed by using a transient absorption technique in the picosecond-microsecond time range, as well as a time-resolved emission technique. The rates of energy transfer from the singlet DPP to ZnPc were found to be extremely fast >10 s , while the rates of electron transfer from the singlet excited state of ZnPc to DPP were found to be 3.7-6.6×10 s .
合成并表征了一类新型的光捕获锌酞菁（ZnPc）-二酮吡咯并吡咯（DPP）杂化物。吸收光谱测量表明，DPP的主要吸收峰（450 - 600 nm）与锌酞菁的吸收峰（300 - 400和600 - 700 nm）互补。因此，所设计的杂化物在可见光区域有较宽的吸收范围。采用从头算B3LYP/6 - 311G方法研究了二元体系的几何和电子结构。发现大多数最高占据分子轨道（HOMOs）位于ZnPc上，而大多数最低未占据分子轨道（LUMOs）位于DPP单元上。DPP单元充当天线，激发后会向连接的ZnPc单元进行高效的单重态-单重态能量转移。形成的单重态ZnPc反过来将其电子给予缺电子的DPP，形成低能的自由基离子对ZnPc - DPP（根据电化学测量计算，能量为1.44 - 1.56 eV）。通过使用皮秒-微秒时间范围内的瞬态吸收技术以及时间分辨发射技术证实了激发态事件。发现从单重态DPP到ZnPc的能量转移速率极快，>10 s ，而从ZnPc的单重激发态到DPP的电子转移速率为3.7 - 6.6×10 s 。
