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Systems Chemistry Approach towards Semiconductive Supramolecular Copolymers with Homo- and Heterometallophilic Interactions

Periodic Reporting for period 2 - SUPRACOP (Systems Chemistry Approach towards Semiconductive Supramolecular Copolymers with Homo- and Heterometallophilic Interactions)

Reporting period: 2018-11-01 to 2020-04-30

Understanding the molecular features governing the self-assembly of functional molecules into functional materials represents a major challenge. For example, to understand why a particular functional material (biological, optoelectronic) works efficiently, it is of utmost importance to program and control the molecular packing. Thus, one of the great challenges of this proposal is to program rationally designed metal complexes to create new materials with unprecedented properties. In particular, the problem to be addressed is to create functional self-assembled materials that are soluble, processable, stimuli-responsive and programmable by understanding the molecular and supramolecular features responsible for these properties. In particular, the use of Pt(II) and Pd(II) complexes and pi-conjugated ligands as building blocks is allowing us to create unprecedented materials with exciting properties, some of them to be yet discovered.

This understanding is important for the society to create new functional materials that can be applicable in optoelectronics and life sciences. For example, the molecular organization in devices such as solar cells, transistors, etc dictates their performance. Or in another example, programming molecules to form water soluble biomaterials is key to better undertstand the operation of biological systems.
The overall objectives are to program metal complexes to self-assemble in a defined fashion to create new materials with superior optical and electronic properties (semiconductivity, dichroism, emission, etc). Also, these materials are expected to be formed and disassembled reversible and controlled by external stimuli such as light and pH. Some of these properties, in particular the stimuli-responsive and excellent optical properties have been already achieved. In the second half of the period, we expect to analyze the electronic properties, such as charge transport.
A summary of the results achieved in the initial 30 months is included in the section project achievements. I have tried to upload a pdf file with the detailed summary but the format is not accepted. I will send it via email.
Some of our findings have gone beyond the state of the art. This includes:
1) WP1: the synthesis of the tetrapyridyl Pd(II) complexes with extended ligands is unprecedented. Given the novelty of these materials, this has gone beyond the state of the art. Exciting properties are envisaged for these systems
2) WP1: the discovery of new, unconventional non-covalent interactions and the existence of concomitant polymorphs is supramolecular polymers is a clear breackthrough in the field. This also allows establish a relationship between self-assembly and crystal engineering, which is relevant for scientists of different disciplines.
3) WP3: we exploited coordination isomerism for the first time to control self-assembly processes, which has allowed to broaden the scope of coordination isomerism and introduce a new method for pathway control in self-assembly.
Until end of the project, we expect to optimize the scope of coordination isomerism and expand it to aqueous medium to create novel stimuli-responsive materials. Also, by synthesizing the new Pt double salts, materials with excellent and unprecedented new properties are envisaged. The same applies to the donor-acceptor systems described in WP4, which are the most challenging systems of the proposal. The synthesis of these systems has just started recently.