A modular approach to underexplored, unsymmetrical 1benzothieno3,2-
b
1benzothiophene (BTBT) scaffolds delivers a library of BTBT materials from readily available coupling partners by combining a ...transition-metal free Pummerer CH-CH-type cross-coupling and a Newman-Kwart reaction. This effective approach to unsymmetrical BTBT materials has allowed their properties to be studied. In particular, tuning the functional groups on the BTBT scaffold allows the solid-state assembly and molecular orbital energy levels to be modulated. Investigation of the charge transport properties of BTBT-containing small-molecule:polymer blends revealed the importance of molecular ordering during phase segregation and matching the highest occupied molecular orbital energy level with that of the semiconducting polymer binder, polyindacenodithiophene-benzothiadiazole (PIDTBT). The hole mobilities extracted from transistors fabricated using blends of PIDTBT with phenyl or methoxy functionalized unsymmetrical BTBTs were double those measured for devices fabricated using pristine PIDTBT. This study underscores the value of the synthetic methodology in providing a platform from which to study structure-property relationships in an underrepresented family of unsymmetrical BTBT molecular semiconductors.
A modular approach to underexplored, unsymmetrical 1benzothieno3,2-
b
1benzothiophene (BTBT) scaffolds, combining a transition-metal free Pummerer CH-CH-type cross-coupling and a Newman-Kwart reaction, delivers a library of BTBT materials.
ortho
-Diethylhexyloxyphenylene benzothiadiazole paracyclophane-1,9-diene as a mixture of diastereomers was synthesized by a sequential benzyne-induced Stevens rearrangement, oxidation and pyrolysis ...of a dithia3.3paracyclophane. Reaction of these highly strained cyclophanedienes with the second generation Grubbs catalyst showed that they can be ring opened to alternating
cis
,
trans
-phenylenevinylene polymers.
In situ
NMR experiments showed that one isomer
8a
polymerised to 90% conversion, whereas the other
8b
gave only 9% conversion due to steric hindrance on both faces of the alkene bridges of this isomer. The resulting polymers can be readily isomerized in dilute solution using visible light to the all-
trans
isomer and the optical and electrochemical properties of these polymers were examined by theory and experiment.
The preparation of highly strained
o
-dialkoxyphenylene benzothiazole paracyclophane-1,9-dienes is reported and the diastereoselectivity of the ring opening metathesis investigated.
Understanding the stability of conjugated polymers towards mechanical stimuli is critical for optimizing the processing and use of these materials in a range of electronic and optoelectronic devices, ...such as transistors, light emitting diodes and solar cells. The fast-growing field of mechanochemistry aims to tame the destructive mechanical forces to perform specific chemical changes in mechanophores but it can also be used to probe the stability of conjugated polymers towards destructive mechanical forces. Using ultrasonication it is possible to benchmark the mechanical integrity of phenylenevinylene block copolymers and show, through experimental studies and DFT simulation, that conjugated olefins are highly stable to
cis
-
trans
isomerisation upon extensive elongation, a useful property for the development of flexible organic electronics.
The performance of flexible electronic devices must be stable to repeated mechanical deformation in use. We show that the structural and optical properties of
cis, trans
-PPVs are maintained when subjected to elongational forces during ultrasonication.
Understanding the stability of conjugated polymers towards mechanical stimuli is critical for optimizing the processing and use of these materials in a range of electronic and optoelectronic devices, ...such as transistors, light emitting diodes and solar cells. The fast-growing field of mechanochemistry aims to tame the destructive mechanical forces to perform specific chemical changes in mechanophores but it can also be used to probe the stability of conjugated polymers towards destructive mechanical forces. Using ultrasonication it is possible to benchmark the mechanical integrity of phenylenevinylene block copolymers and show, through experimental studies and DFT simulation, that conjugated olefins are highly stable to
cis
–
trans
isomerisation upon extensive elongation, a useful property for the development of flexible organic electronics.
The highly strained ortho-diethylhexyloxy 2.2paracyclophane-1,9-diene (M1) can be synthesized by ring contraction of a dithia3.3paracyclophane using a benzyne-induced Stevens rearrangement. This ...paracyclophanediene undergoes ring-opening metathesis polymerization to give well-defined 2,3-dialkoxyphenylenevinylene polymers with an alternating cis/trans alkene stereochemistry and controllable molecular weight. Fully conjugated block copolymers with electron-rich and electron-deficient phenylene vinylene polymer segments can be prepared by sequential monomer additions. These polymers can be readily isomerized to the all-trans stereochemistry polymer. The optical and electrochemical properties of these polymers were investigated by theory and experiment.
-Diethylhexyloxyphenylene benzothiadiazole paracyclophane-1,9-diene as a mixture of diastereomers was synthesized by a sequential benzyne-induced Stevens rearrangement, oxidation and pyrolysis of a ...dithia3.3paracyclophane. Reaction of these highly strained cyclophanedienes with the second generation Grubbs catalyst showed that they can be ring opened to alternating
,
-phenylenevinylene polymers.
NMR experiments showed that one isomer 8a polymerised to 90% conversion, whereas the other 8b gave only 9% conversion due to steric hindrance on both faces of the alkene bridges of this isomer. The resulting polymers can be readily isomerized in dilute solution using visible light to the all-
isomer and the optical and electrochemical properties of these polymers were examined by theory and experiment.
The synthesis of donor-acceptor di-, tri- and tetrablock copolymers
via
sequential ROMP of electron rich and electron deficient paracyclophanediene monomers using Grubbs ruthenium carbene initiator,
...G3
, is discussed. Block copolymers were initially formed with a
cis
/
trans
alkene geometry and these can be readily photoisomerised to the all
trans
forms. The optical and electrochemical properties of these block copolymers were examined by theory and experiment, and it was found that the HOMO and LUMO energy levels are localised on the donor and acceptor blocks, respectively.
Sequential ROMP of electron rich and electron deficient paracyclophanediene monomers gives donor-acceptor di-, tri- and even tetrablock phenylenevinylene coploymers.
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