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ISSN 1998-9539

Effect of Transition Metal Cations on Assembly of Highly Ordered 2D Multiporphyrin Arrays on Liquid and Solid Substrates

E. V. Ermakova,a Yu. Yu. Enakieva,a A. I. Zvyagina,a Yu. G. Gorbunova,a,b M. A. Kalinina,a and V. V. Arslanova@

aFrumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia

bKurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia

@Corresponding author E-mail: vladimir.arslanov@gmail.com

 

DOI: 10.6060/mhc161177a

Macroheterocycles 2016 9(4) 378-386

 

Metal-ligand supramolecular coordination at the air/water interface offers a route to generate highly ordered 2D multichromophore architectures for fabricating film-like surface attached metal organic frameworks (SURMOF) for applications in electronics, photonics and chemical sensing. Metal complexes of tetrapyridyl porphyrins (TPyP) are well known as convenient building blocks for the assembly of 3D coordination polymers. Herein, we suggest a new strategy of the assembly of highly ordered 2D coordination networks in Langmuir monolayers by using non-metalated ligands as starting tectones, instead of the metal complexes of tetrapyridyl porphyrin. High degree of structural ordering of 2D multiporphyrin arrays with face-on orientation of macrocycles is achieved by the interaction of metal ions with peripheral groups of the ligand as well as with macrocyclic core. A combination of thermodynamic analysis with spectral studies was applied to determination of both types of complex formation in the monolayer. Structural order in 2D hybrid networks depends on the type of initiating metal ion and it increases in a row Cd(II) < Cu(II) < Zn(II). In the presence of metal ions in the subphase, the monolayer of ТРуР undergoes fluorescence quenching. This monolayer comprises mostly a MТРуР with low quantum yield, whereas all observed fluorescence is determined by small amounts of the free ligand controlled by the metalation process in the monolayer. The as-formed hybrid 2D coordination networks with tunable degree of macrocycle metalation can be hierarchically integrated into variously ordered multilayer MOFs. We also demonstrated structural similarity between the monolayers at the air/water interface and related multilayer SURMOFs fabricated on solids by Langmuir-Schaefer technique. The fluorescence quenching in these water-stable SURMOF films makes it possible to use them for the development of SURMOF-based nanosensors. 

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