Fulvenyl-Functionalized Polyisocyanides: Redox-active (Cross-) Conjugated Polymers as Materials for Organic Polymer Batteries and Electrochromic Diodes
Synthesis and Properties of Functional Materials
Preparatory and Physical Chemistry of Polymers
Final Report Abstract
In the course of this project, we were able to establish synthetic accesses to two types of fulvenylfunctionalized isocyanides (M1/M2) and to the corresponding polyisocyanides (P1/P2). Polymer P1e shows particular potential for applications in organic electronics, as it exhibits a high electron affinity (LUMO = -3.45 eV), and a near record high electron mobility of 1.04 (±2.5)*10-2 cm2/Vs. Type 2 polymers (P2a/P2d, P2i) show equally great promise for further development, due to their unusually low optical gaps and high electron affinities (in case of P2a/P2b) that are likely caused by extensive π-π-stacking of the fulvenyl sidechains along the polymer backbone. We also made block-copolymers accessible (BP11, BP4, BP5) and proved their general suitability for the fabrication of single component organic photovoltaic cells. Furthermore, we prepared, characterized, and published gold(I) chloride complexes (Au1/Au2) of nearly all isocyanide monomers. These works were also very well received by the scientific community and broadened scope and appeal of this project significantly. Overall, we have very successfully established this new class of materials, and opened a broad range of opportunities for synthetic development and optimization, as well as for their application in organic electronic devices. Outlook: Aside from the obvious possibility of the optimization of electronic properties, a key issue that needs to be addressed in the future, is the fact that none of the investigated polymers showed no melting/crystallization or glass-transitions prior to decomposition. Thermal annealing near the glass transition or melting temperature is typically required to effect self-organization of blockcopolymers into well-defined separate phases. Therefore, the available polymers cannot self-organize into a thermodynamically morphology. Furthermore, the chemical stability of Type 2 monomers needs to be improved. This may be achieved through substitution of the H-atom on the exocyclic fulvene-bond by F or alkyl-groups (P4, X = F, CH3). Finally, a point that we have not been able to address yet, is the synthesis of -block-PIC BCPs (e.g. P(M2i-b-M2a)). This type of material would make sole use of the properties of PICs, and would therefore more pure show their potenitialities, as compared to BCP with conjugated polyarenes.
Publications
- “Fulvenyl-functionalized Polyisocyanides – Cross-conjugated Electrochromic Polymers With Variable Optical and Electrochemical Properties”, Macromolecules 2018, 51, 5323-5335
S. Schraff, Y. Sun, F. Pammer
(See online at https://doi.org/10.1021/acs.macromol.8b00977) - “Gold(I) Complexes of Fulvenyl-functionalized Arylisocyanides”, Eur. J. Inorg. Chem. 2019, 42-50
S. Schraff, Y. Sun, A. Orthaber, F. Pammer
(See online at https://doi.org/10.1002/ejic.201801031) - “All-Conjugated Donor-Acceptor Block Copolymers featuring a Pentafulvenyl-Polyisocyanide-Acceptor”, Polymer Chem. 2020, 11, 1852-1859
S. Schraff, S. Maity, L. Schleeper, Y. Dong, S. Lucas, A. A. Bakulin, E. von Hauff, F. Pammer
(See online at https://doi.org/10.1039/C9PY01879D) - “Asymmetric Chain-growth Synthesis of Polyisocyanides with Chiral Nickel Pre-Catalysts”, J. Polym. Sci. A: Polym. Chem. 2020, 58, 2221-2233
S. Schraff, N. M. Kreienborg, J. Trampert, Y. Sun, A. Orthaber, C. Merten, F. Pammer
(See online at https://doi.org/10.1002/pol.20200153)
