Conjugated Metallo-Supramolecular Polymers Containing a Phosphole Unit

Abstract

International audienceA new building block, TPT, composed of the substituted phosphole ring surrounded by two thiophene rings with 2,2':6',2''-terpyridine-4'-yl (tpy) end-groups, is prepared and assembled with metal ions (Co2+, Cu2+, Fe2+, Ni2+ and Zn2+) into metallo-supramolecular polymers (MSPs) and properties of both TPT and the MSPs are compared with those of their counterparts with terthiophene central blocks. A distinct red shift of the UV/vis band about 60 to 100 nm proves the decrease in the bandgap energy due to replacing the thiophene-2,5-diyl with a phosphole-2,5-diyl central unit, which is due to the lowered aromaticity of phosphole ring compared to the aromaticity of thiophene ring. Assembling of TPT with metal ions gives oligomeric chains comprising up to ten unimeric units in dilute solutions. MSPs with Fe2+ and Ni2+ ion couplers exhibit very slow constitutional dynamics, while those with Cu2+ and Zn2+ ion couplers quite fast constitutional dynamics. A metal to ligand charge transfer is observed only for Fe2+-MSPs, while luminescence only for Zn2+-MSPs, mainly at an excess of Zn2+ ions, which indicates a positive effect of the end-capping of MSP chains with these ion

Singlet fission in thin films of metallo-supramolecular polymers with ditopic thiophene-bridged terpyridine ligands

“…Evidence supporting the formation of excimers in the solid T has been recently obtained also from the luminescence spectra of the solid T diluted in the solid KBr. 37 The excimer formation also explains the extraordinary large Stokes shift observed for the solid T. The difference between the Stokes shifts of T observed for the thin film and diluted solution, respectively, 18,24 which is equal to ca. 0.8 eV, can be regarded as the stabilization energy of the excimer according to ref.…”

Iron (II) Metallo-Supramolecular Polymers Based on Thieno[3,2-b]thiophene for Electrochromic Applications

“…The red color of Fe-MSPs is rather surprising because the “generic” color of MSPs with [Fe(tpy) 2 ] 2+ centers is blue due to the very intense MLCT band occurring at 550 nm and above [ 12 , 32 ]. Nevertheless, it is also well known that this MLCT band is significantly contributed by transitions in the central parts of unimeric units [ 24 , 25 , 26 , 27 ]. This interesting feature can potentially help in easy color tuning the EC devices based on bis( tpy ) Fe-MSPs because their electrochromism is closely related to the color changes accompanying the MSP assembling, which are easy to determine.…”

“…MSPs derived from α,ω-bis( tpy ) unimers with short oligophenylene [ 19 ] or oligothiophene [ 15 , 16 ] central units represent a significant portion of already reported electrochromic MSPs. Those derived from unimers with oligothiophene central units have been the subject of our studies [ 23 , 24 , 25 , 26 ] that we later on extended to include phosphole [ 27 ] and thieno[3,2- b ]thiophene [ 28 ] central units. These new unimers and their MSPs exhibited redshifted absorption (narrower energy bandgap) and increased fluorescence quantum yield compared to the counterparts with central units composed exclusively of thiophene-2,5-diyl units.…”

Terpyridine-Containing π-Conjugated Polymers for Light-Emitting and Photovoltaic Materials

“…Contrarily, Vitvarová et al ( 2017 ) synthesized a novel building block that comprised a substituted phosphole ring surrounded by two thiophene rings with tpy fragments as end-groups. It was then coordinated with metal ions such as Co 2+ , Cu 2+ , Fe 2+ , Ni 2+ , and Zn 2+ to produce metallo-supramolecular polymers (MSPs).…”