Synthesis and Optical Properties of α,β‐Unsaturated Ketones Bearing a Benzofuran Moiety

Abstract

Five p-expanded a,b-unsaturated ketones have been prepared from as trongly electron-richb enzofuran derivative via Knoevenagel reactiona nd aldol condensation. The incorporation of two 6-didodecylaminobenzofuran-2-yl groups at the periphery of D-p-A and D-p-A-p-D molecules resulted in dyes with excellents olubility in the majority of organic solvents. In contrasttothe majority of a,b-unsaturat-ed ketones,t hese dyes emit relatively strongly in the red region with af luorescenceq uantum yield up to 40 %. They also display strong solvatofluorochromism with emission shiftingf rom 570 nm in toluene to 670 nm in CHCl 3 .D epending on the chemical structure, they two-photon cross-sections( s 2 )a re up to 1700GM( 1GM= 10 50 cm 4 s photon À1 ).were varied between 9.0 10 -7 -1.5 10 -5 m for optimal signal intensities, depending on the dye and solvent used.

High-speed two-photon polymerization 3D printing with a microchip laser at its fundamental wavelength

“…To improve the 2PP process, a recently synthesized photoinitiator based on an α,βunsaturated 1,3-diketone [22] was used ( Fig. 1(a)).…”

“…1(b)), which given its dipolar D-π-A architecture should lead to strong two-photon absorption at ~1040 nm. Initial two photon absorption assessment of the synthesized photoinitiator is reported in [22]. The dye is highly transparent in the NIR with only background absorption (see inset in Fig.…”

Photoinitiators for two-photon polymerisation: effect of branching and viscosity on polymerisation thresholds

“…[15][16][17] A number of research groups have utilised carbonyl moieties in the creation of 2PA PIs, with high sensitivity and low polymerisation thresholds. 2,3,11,[17][18][19][20][21] These are oen focussed on several well-known functional components, including; a-b-unsaturated ketones, 3,16,21 thioxanthones, 1,15 ketocoumarins, 19,22 1,3-diketones 23 and acylo-phosphine oxides. 24 Furthermore, many groups have produced dipolar, quadrupolar and octupolar PIs for TPP.…”

Annulated Azuleno[2,1,8‐ija]azulenes: Synthesis and Properties

“…It is noteworthy that both aldol condensations occurred in α positions of the same ketone, which is dissimilar to what Gryko and co-workers reported for the same dione upon condensation with benzofuran moieties. [21] After the deprotection of the aldehyde groups, a two-fold intramolecular aldol condensation produced compound 7 with the thiophene in the syn configuration as confirmed by 13 C NMR spectroscopy (see Supporting Information section). Nucleophilic addition using lithium TIPS-acetylide followed by a reduction with Scheme 1.…”