Novel dispirobifluorenes and indeno-spirobifluorenes: syntheses and properties

ortho‐, meta‐, and para‐Dihydroindenofluorene Derivatives as Host Materials for Phosphorescent OLEDs

“…[10] In another recent example, Haley et al synthe-sized a new class of appealing electron-accepting materials based on an antiaromatic, fully conjugated [2,1-c]indenofluorene backbone (bridged ortho-terphenyl). [7] However, the aromatic p-conjugated analogue, the dihydroindeno[2,1-c]fluorenyl core described in this work (incorporated in 3, Scheme 1), is almost absent from literature [12][13][14] and its intrinsic properties have never been studied. Due to the importance of the dihydroindeno [1,2-b]fluorene in organic electronics, it is of great interest to design and incorporate the other dihydroindenofluorene isomers in other optoelectronic devices.…”

ortho‐, meta‐, and para‐Dihydroindenofluorene Derivatives as Host Materials for Phosphorescent OLEDs

“…In this context our group has, for example, recently reported the first incorporation of bridged meta-terphenyls, i.e. dihydroindeno[1,2-a]fluorene and dihydroindeno[2,1-b]fluorene, in nondoped blue OLEDs.[10] In another recent example, Haley et al synthesized a new class of appealing electron-accepting materials based on an antiaromatic, fully conjugated [2,1-c]-indenofluorene backbone (bridged ortho-terphenyl).[7] However, the aromatic p-conjugated analogue, the dihydroindeno[2,1-c]fluorenyl core described in this work (incorporated in 3, Scheme 1), is almost absent from literature [12][13][14] and its intrinsic properties have never been studied. Due to the importance of the dihydroindeno[1,2-b]fluorene in organic electronics, it is of great interest to design and incorporate the other dihydroindenofluorene isomers in other optoelectronic devices.…”

Straightforward Synthesis and Properties of Highly Fluorescent [5]‐ and [7]‐Helical Dispiroindeno[2,1‐c]fluorenes

“…For example, twisted π‐system countenances fast intersystem crossing from singlet to triplet states, resulting in low fluorescence quantum yields of helicenes . Although SBFs and helicenes have been studied for a long time, the studies of materials combining both structural motifs are rare in literature . The asset of the combination of the above‐mentioned principles, that is, helicity and the SBF moiety, have been sporadically indicated by photophysical properties of helical bitriphenylene, [5]‐helical spiroindenofluorene and dispiroindenofluorene (DSIF) which exhibited considerably high fluorescence with quantum yields of 30, 83, and 70 %, respectively.…”

“…Although SBFs and helicenes have been studied for a long time, the studies of materials combining both structural motifs are rare in literature . The asset of the combination of the above‐mentioned principles, that is, helicity and the SBF moiety, have been sporadically indicated by photophysical properties of helical bitriphenylene, [5]‐helical spiroindenofluorene and dispiroindenofluorene (DSIF) which exhibited considerably high fluorescence with quantum yields of 30, 83, and 70 %, respectively. The indeno[2,1‐ c ]fluorene (IF) core in 5,8‐dihydroindeno[2,1‐ c ]fluorene (DHIF) (Figure ) represents a suitable structural motif for a combination of helicity with SBF, but the lack of synthetic procedures or a general synthetic methodology for its preparation limits further insight to structure‐property relationship and complicates tuning of the physical properties.…”

“…Only a handful of reports have been published for the preparation of DHIF and its substituted derivatives . Worth mentioning are works by Chen, Liu, Yuan, and especially by Poriel . Synthesis of fully conjugated indeno[2,1‐ c ]fluorenes was reported by Haley .…”