Department of Pharmaceutical Chemistry and Drug Control, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove, 50005, Czech Republic.
Phys Chem Chem Phys. 2010 Mar 20;12(11):2555-63. doi: 10.1039/b918546a. Epub 2010 Jan 21.
A series of octasubstituted zinc(II) tetrapyrazinoporphyrazines (TPyzPz), aza-analogues of phthalocyanines, differing in the number of peripheral N,N-diethylamino (n = 0-8) and tert-butylsulfanyl substituents (m = 8-n) has been synthesized. All possible congeners were characterized including adjacent and opposite isomers. Steady-state (UV-vis, fluorescence) and time-resolved (fluorescence, femtosecond transient absorption) spectroscopies, redox and photochemical (singlet oxygen formation) properties were investigated and compared. The peripheral tertiary amino substituents (donor) induce a new competitive relaxation pathway to fluorescence and intersystem crossing due to the mixing of the first excited state S(1) of the TPyzPz macrocycle with a nearby intramolecular charge transfer (ICT) state. The fluorescence quantum yield and fluorescence lifetime of 6Zn bearing one N,N-diethylamino substituent (n = 1, m = 7) decreased with increasing solvent polarity, while the same observables of 5Zn with no donor centre (n = 0, m = 8) were not affected. Protonation of the N,N-diethylamino substituent in 6Zn led to a strong increase of the fluorescence intensity. The cyclic voltammetry data, the steady-state and time-resolved emission and transient absorption studies revealed strong electronic coupling between the TPyzPz moiety and N,N-diethylamino substituents. ICT is an extremely rapid process occurring with a time constant of 10 ps and 7 ps in 6Zn (n = 1, m = 7) and 11Zn (n = 8, m = 0) in pyridine, respectively. The ICT efficiency decreased in non-polar solvents. The presence of two N,N-diethylamino substituents in 7Zn (n = 2, m = 6) considerably quenched the S(1) states in pyridine (polar, coordinating), toluene (non-polar, non-coordinating) and toluene-1% pyridine (v/v) (non-polar, coordinating). The photophysical properties of compounds with more donor substituents on the periphery (n > 2, m < 6) were similar to those of 7Zn.
一系列八取代的锌(II)四吡嗪并卟啉嗪（TPyzPz），即酞菁的氮杂类似物，在取代基 N,N-二乙基氨基（n = 0-8）和叔丁基硫基（m = 8-n）的数量上存在差异。所有可能的同系物都进行了表征，包括相邻和相反的异构体。通过稳态（UV-vis、荧光）和时间分辨（荧光、飞秒瞬态吸收）光谱、氧化还原和光化学（单线态氧形成）性质的研究和比较。外围的叔氨基取代基（供体）由于 TPyzPz 大环的第一激发态 S(1)与附近的分子内电荷转移（ICT）态混合，诱导了一条新的竞争弛豫途径至荧光和系间窜越。带有一个 N,N-二乙基氨基取代基（n = 1，m = 7）的 6Zn 的荧光量子产率和荧光寿命随着溶剂极性的增加而降低，而没有供体中心的 5Zn（n = 0，m = 8）的相同观测值不受影响。6Zn 中 N,N-二乙基氨基取代基的质子化导致荧光强度的大幅增加。循环伏安法数据、稳态和时间分辨发射和瞬态吸收研究表明，TPyzPz 部分和 N,N-二乙基氨基取代基之间存在强烈的电子耦合。ICT 是一个极其快速的过程，在吡啶中分别以 6Zn（n = 1，m = 7）和 11Zn（n = 8，m = 0）中的 10 ps 和 7 ps 的时间常数发生，在非极性溶剂中，ICT 效率降低。7Zn（n = 2，m = 6）中存在两个 N,N-二乙基氨基取代基，在吡啶（极性、配位）、甲苯（非极性、非配位）和甲苯-1%吡啶（v/v）（非极性、配位）中，大大猝灭了 S(1)态。具有更多外围供体取代基（n > 2，m < 6）的化合物的光物理性质与 7Zn 相似。
