A non-covalent supramolecular complex combining porphyrin (Por), phthalocyanine (Pc) and fullerene [ C 60], was obtained through zinc metal-pyridine coordination between a covalently meso-linked heterodimer ZnPor-ZnPc (4) and a N-pyridylfulleropyrrolidine derivative (5). The complexation was studied in toluene by absorption and fluorescence binding studies, and evidenced that the coordination of the N-pyridylfulleropyrrolidine (5) occurs preferentially through the zinc ion center of ZnPc (log K > 6.0) rather than ZnPor (log K = 5.23). Steady-state and time-resolved spectroscopies evidenced that upon selective excitation of either the Por, or the Pc moiety in [( ZnPor-ZnPc )∪ C 60], the singlet excited state of Pc was generated efficiently in both cases (either from singlet-singlet energy transfer from 1Por* to Pc, or directly after selective excitation of the Pc moiety). Next, an electron transfer occurred from the 1Pc* to the C 60 to generate the charge-separated specie [( ZnPor-ZnPc •+)∪ C 60•-]. Finally, the back electron transfer afforded the Pc triplet excited state rather than the ground state. The introduction of a covalent meso-linkage between Por and Pc in the heterodimer 4 and in the supramolecular assembly 4∪5 induces appreciable differences toward the photo-induced processes and the binding constants in comparison with other β-covalently linked analogue systems.
通过锌金属-吡啶配位,在共价中链异二聚体 ZnPor-ZnPc (4) 和 N-吡啶基富勒吡咯烷衍生物 (5) 之间获得了卟啉 (Por)、酞菁 (Pc) 和富勒烯 [ C 60] 的非共价超分子复合物。在甲苯中通过吸收和荧光结合研究了这种复合物,结果表明,N-吡啶基富勒吡咯烷(5)优先通过 ZnPc(log K >6.0)而不是 ZnPor(log K = 5.23)的锌离子中心发生配位。稳态光谱和时间分辨光谱证明,在对[( ZnPor-ZnPc )∪ C 60]中的 Por 或 Pc 分子进行选择性激发时,Pc 的单线激发态在两种情况下都能有效地产生(从 1Por* 到 Pc 的单线-单线能量转移,或直接在 Pc 分子被选择性激发后产生)。接着,电子从 1Pc* 转移到 C 60,生成电荷分离的物质[( ZnPor-ZnPc -+)∪ C 60--]。最后,反向电子转移产生了 Pc 三重激发态而非基态。在异源二聚体 4 和超分子组装体 4∪5 中,Por 和 Pc 之间引入了共价中间连接,这使得光诱导过程和结合常数与其他 β 共价连接的类似体系相比有明显的不同。