Spiro‐Bridged Ladder‐Type Oligo(para‐phenylene)s: Fine Tuning Solid State Structure and Optical Properties

Abstract

A set of ladder-type quaterphenyls with an incremental number of spiro-bifluorene units in the bridge positions as well as an in-plane bent quaterphenyl carrying all bridges on one and the same side of the ribbon are synthesized and characterized. While spiro-bifluorene substituents lead to bathochromically shifted maxima in the UV-vis absorption spectra, this effect can be compensated by in-plane bending. The influence of different deposition techniques on the solid state structure is analyzed by X-ray diffraction of single crystals obtained by crystallization from solution as well as sublimation. An increasing number of spiro-bifluorene substituents are found to aid thin-film formation.

Rigidly Fused Spiro‐Conjugated π‐Systems

“…To promote vacuum process ability and single crystal growth, Hecht et al explicitly omitted solubilizing groups. [19] Accordingly, compounds 11, 12, and 13 (Scheme 3) with methyl or spiro-fused fluorene were designed and synthesized. Single crystals from these three compounds were easily obtained through solution crystallization, or sublimation; however, the disparate crystal growth methods resulted in different crystal structures for compound 12 and 13 molecules.…”

“…In combination with the yellow emitter 3,4,5,6-tetrakis(3,6-diphenyl-carbazol-9yl)-1,2-dicyanobenzene (4CzPNPh), white OLEDs are capable of offering a turn-on voltage of 3.5 V and a current efficiency (CE) of 3.6 Cd A À 1 , along with CIE coordinates of (0.29, 0.33). [21] Regarding the spiro-fused dihydroindenofluorene family, Poriel et al systematically investigated four positional isomer compounds (16)(17)(18)(19), Scheme 6) with three different phenyl linkages (para/meta/ortho), and two different ring bridge arrangements (anti/syn). [3,[22][23][24] As shown in Figure 4, compounds 1 and 16-19 displayed very similar low-energy absorption edges in THF solution, whereas their band intensities were significantly different.…”

“…To promote vacuum process ability and single crystal growth, Hecht et al. explicitly omitted solubilizing groups [19] . Accordingly, compounds 11 , 12 , and 13 (Scheme 3) with methyl or spiro‐fused fluorene were designed and synthesized.…”

A–π–A, D–π–D and D–π–A blue emitting fluorophores based on dispiro[fluorene-9,6′-indeno[1,2-b]fluorene-12′,9′′-fluorene]

“…32 DSF-IF is also found as building block in fused extended -conjugated systems. [33][34][35][36] From an organic chemistry point of view, the formation of the two spiro bridges of substituted DSF-IF compounds has been the purpose of several synthetic studies, which have led to a new generation of DSF-IF positional isomers. 15,37,38 However, this scaffold is not restricted to organic electronic applications since its appealing 3D geometry has allowed to design predictably ordered materials, 39 liquid crystals, 40 electroactive polymers, 24,28 showing its interesting versatility.…”

Influence of the pendant substituent at the C1 position of a spirobifluorene scaffold on the electronic properties

“…This key characteristic has been advantageously used to design high triplet energy materials (E T 4 2.7 eV), which are particularly attractive for hosting phosphors in phosphorescence OLEDs (PhOLEDs). [22][23][24] Poly-substituted organic materials with specific properties have also been investigated, taking advantage from the different SBF positions (C1 [25][26][27][28] and C3 [29][30][31] ).…”