Modular Synthesis of Benzene-Centered Porphyrin Trimers and a Dendritic Porphyrin Hexamer
摘要:
Rigid, star-shaped D-3-symmetric arrays have been synthesized in which three porphyrin macrocycles are attached to the 1, 3, and 5 positions each of a benzene core through linkers consisting of collinear repetitive phenylethynyl units. Using the same methodology, a dendridic porphyrin hexamer having an external diameter of ca. 10 nm has been also obtained. By successive substitution of the three benzene positions, both a porphyrin trimer, the three linkers of which are of different length, and a starlike porphyrin, in which the complexed metal ions are different from each other, have been synthesized. The latter is the first example of a prochiral arrangement of metal ions in a D-3-symmetric ligand. To investigate their capability of forming ordered self-assembled monolayers on gold substrates, some of the porphyrin trimers and the dendritic porphyrin hexamer described in this work bear meta-thioanisole units at the apical positions. Analogously to similar multiporphyrin systems described in the Literature, in which, however, the chromophores were arranged collinearly, the interaction between the chromophores of the multiporphyrin arrays described in this work is negligible, in the ground state, while effective energy transfer takes place in the singlet excited state.
to the 1, 3, and 5 positions of a benzene core through linkers consisting of collinear repetitive phenylethynyl units have been carried out using Pd(0)-catalyzed coupling reactions. By the same procedure, an analogous 10-(4-pyridin-yl)porphyrin hexamer in which all positions of the benzene core are substituted has been obtained. Likewise, the preparation of suitably sized cyclic porphyrin hexamers, in
八个新的星形D(3)对称阵列的合成,其中三个15-(吡啶-4-基)卟啉亚基通过由共线重复的连接子连接到苯核的1、3和5位苯乙炔基单元已使用Pd(0)催化的偶联反应进行。通过相同的步骤,获得了类似的10-(4-吡啶基-基)卟啉六聚体,其中苯核的所有位置均被取代。同样,详细描述了适当大小的环状卟啉六聚物的制备,其中所有六个或至少三个交替的卟啉环均与Zn(II)离子络合。在解决方案中,这种环状卟啉六聚体与星形聚卟啉形成超分子组装,其中星形聚卟啉通过顶端吡啶环与Zn(II)离子的配位而保持在大环的内部。所建议的结构由(1)H NMR光谱和MALDI-TOF质谱测量支持。它们与相应的超分子的结合常数的高值一致,其范围在K = 1.1 x 10(10)和1.4 x10(9)M(-1)之间。