摘要
研究了不同磺化度的酞菁在甲醇－水混合溶剂中的聚集行为．通过紫外－可见光谱测定，发现磺化度在1．0以上时染料在稀溶液中主要以单体和二聚体的形式存在，并可用简便的方法计算出聚集平衡常数和平衡时单体所占的百分比，得到磺化度越低越易聚集的结论．有关激发态的实验表明，增加酞菁磺化度有助于提高表观荧光量子产率，但对荧光寿命影响较小．
Phthalocyanines can be used as dyes, optical and electrical materials, catalysts and models for naturally existing macrocycles([1]), especially it can be one of the possible candidates for photodynamic therapy([2]) (PDT). Particular attention has focused on its sulfonated derivatives because they are highly water-soluble and show great promise in PDT since they can be retained by tumor tissues. However, as with other water-soluble dyestuffs([3]), the sulfonated phthalocyanines tend to dimerize in aqueous solutions. These aggregates will depress the photoactivity of these dyes and phototoxicity towards biological tissues since their major pathway of deactivation is through internal conversion process to the ground state([4]). Thus, it is important to evaluate quantitatively the influence of sulfonation on aggregation([5]) and other photophysical properties of phthalocyanine dyes. In the present work, we try to illustrate the effect of sulfonation degree on dimerization for metal-free sulfonated phthalocyanines (HSPCs). The dimerization equilibrium constant (K) and the percentage of monomer in the solution (alpha) were obtained spectrophotometrically. The quantum yield of fluorescence (phi(f)) and the lifetime of the singlet excited state (tau(f)) of these sulfonated phthalocyanines have also been measured. These confirm an inverse order between the extent of dimerization and the sulfonation degree or these sulfonated phthalocyanines.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1996年第2期163-168,共6页
Acta Physico-Chimica Sinica
