302906-79-2

Upstream product

• 34904-03-5 4-(N,N-dimethylamino)benzyltriphenylphosphonium iodide 
• 302906-76-9 (E)-2-formyl-6,6'-bis(4,5-dihydro-6H-cyclopenta[b]thienylidene) 
• 302906-75-8 (E)-4,5,4',5'-Tetrahydro-[6,6']bi[cyclopenta[b]thiophenylidene] 
• 121-69-7 N,N-dimethyl-aniline 

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• 302906-83-8 (E)-2-formyl-2'-[(E)-(4-N,N-dimethylaminobenzylidene)methyl]-6,6'-bis(4,5-dihydro-6H-cyclopenta[b]thienylidene) 

Relevant academic research and scientific papers

Design and synthesis of push-pull chromophores for second-order nonlinear optics derived from rigidified thiophene-based π-conjugating spacers

Two series of push-pull chromophores built around thiophene-based π-conjugating spacers rigidified either by covalent bonds or by noncovalent intramolecular interactions have been synthesized and characterized by UV-vis spectroscopy, electric field induced second harmonic generation (EFISH) and differential scanning calorimetry. Comparison of the linear and second-order nonlinear optical properties of chromophores based on a covalently bridged dithienylethylene (DTE) spacer with those of their analogues based on open chain DTE shows that the rigidification of the spacer produces a considerable bathochromic shift of the absorption maximum together with a dramatic enhancement of the molecular quadratic hyperpolarizability (μΒ) which reaches values among the highest reported so far. A second series of NLO-phores has been derived from a 2,2′-bi(3,4-ethylenedioxythiophene) (BEDOT) π-conjugating spacer. As indicated by X-ray and UV-vis data, rigidification of the spacer originates in that case, from noncovalent intramolecular interactions between sulfur and oxygen atoms. Again, comparison with the parent compounds based on an unsubstituted bithiophene spacer reveals a marked red shift of the absorption maximum and a large enhancement of μΒ. In an attempt to distinguish the contribution of the electronic and geometrical effects of the ethylenedioxy group, a third series of NLO-phores based on 3,4-ethylenedioxythiophene (EDOT) and 3,4-dihexyloxythiophene spacers has been synthesized. Comparison with compounds based on unsubstituted thiophene shows that, despite a red shift ofλmax, introduction of alkoxy groups leads to a decrease of μΒ. Theoretical calculations indicate that this effect results from a decrease of the dipole moment (μ) caused by the auxiliary electron-donor alkoxy groups on the thiophene ring. In contrast, replacement of BT by BEDOT produces an increase of μ, which associated with the noncovalent rigidification of the BT system accounts for the observed enhancement of μΒ.

Huge enhancement of the quadratic nonlinear optical susceptibility in push-pull chromophores based on bridged dithienylethylene spacers

Replacement of the open chain dithienylethylene π-conjugating spacer by its bridged analog in push-pull NLO-phores produces a dramatic increase of the quadratic hyperpolarisability.