Favereau Ludovic, Cnossen Arjen, Kelber Julien B, Gong Juliane Q, Oetterli René M, Cremers Jonathan, Herz Laura M, Anderson Harry L
Chemistry Research Laboratory, Department of Chemistry, University of Oxford , Oxford OX1 3TA, United Kingdom.
Clarendon Laboratory, Department of Physics, University of Oxford , Oxford OX1 3PU, United Kingdom.
J Am Chem Soc. 2015 Nov 18;137(45):14256-9. doi: 10.1021/jacs.5b10126. Epub 2015 Nov 6.
Five-coordinate geometry is the standard binding mode of zinc porphyrins with pyridine ligands. Here we show that pseudo-octahedral six-coordinate zinc porphyrin complexes can also be formed in solution, by taking advantage of the chelate effect. UV-vis-NIR titrations indicate that the strength of this second coordination is ca. 6-8 kJ mol(-1). We have used the formation of six-coordinate zinc porphyrin complexes to achieve the template-directed synthesis of a 3D π-conjugated spiro-fused array of 11 porphyrin units, covalently connected in a nontrivial topology. Time-resolved fluorescence anisotropy experiments show that electronic excitation delocalizes between the two perpendicular nanorings of this spiro-system within the experimental time-resolution of 270 fs.
五配位几何结构是锌卟啉与吡啶配体的标准结合模式。在此我们表明，利用螯合效应，伪八面体六配位锌卟啉配合物也能在溶液中形成。紫外-可见-近红外滴定表明这种二级配位的强度约为6 - 8 kJ mol⁻¹。我们利用六配位锌卟啉配合物的形成实现了由11个卟啉单元组成的三维π共轭螺稠阵列的模板导向合成，这些卟啉单元以一种复杂的拓扑结构共价连接。时间分辨荧光 anisotropy实验表明，在270 fs的实验时间分辨率内，电子激发在这个螺环系统的两个垂直纳米环之间离域。
