Dimension-controlled assemblies of modified bipyrroles stabilized by electron-withdrawing moieties

Abstract

Benzoyl-substituted bipyrroles possessing aliphatic chains were synthesized and formed a variety of dimension-controlled assembled structures as mesophases through various intermolecular interactions.

A computer algorithm to discover iterative sequences of organic reactions

“…As the first set of examples of previously undescribed iterations, we consider the syntheses of various poly(heterocycles) shown in Fig. 3 that are potentially useful in molecular electronics [24][25][26] and sensing 27 . We chose this family for illustration because the iterations do not conventionally couple the heterocyclic subunits but instead build them from acyclic precursors (allowing more flexible substitution patterns; groups marked as R in the figure) and because the key, ring-forming steps have close literature precedents (Supplementary Fig.…”

2,2′-Bipyrrole-Based Porphyrinoids

“…Furthermore, the electronic structure of the bipyrrole unit can enhance global π-conjugation of macrocycles by the deprotonation-coupled oxidation of the electron-rich bipyrrole π-system. In fact, 2,2′-bipyrroles with electron-withdrawing benzoyl groups are highly polarized, which induces dipole–dipole interaction, π–π stacking, and hydrogen-bonding interaction leading to unique self-assemblies applicable to functional materials. , Such features of bipyrrole endow various porphyrinoids with interesting structures and properties, and these bipyrrole-based systems continue to occupy a very important part of porphyrinoid chemistry. − One of the most intriguing applications is anion supramolecular chemistry, such as sensing, templating, extraction, and catalysis, , and porphyrinoids are considered to have potential application to these research areas. , In this sense, a brief overview of the chemistry of bipyrrole-containig porphyrinoids is intended here, especially focusing on their synthesis and structure. Section describes synthetic methods for 2,2′-bipyrroles.…”

Conformation-Changeable π-Electronic Systems with Metastable Bent-Core Conformations and Liquid-Crystalline-State Electric-Field-Responsive Properties

“…In our previous study, bipyrroles substituted with modified benzoyl units at the α-positions and possessing four or six aliphatic chains generated several assembled structures, such as liquidcrystalline mesophases, via intermolecular interactions. 8 Notably, bipyrrole derivatives are considered unique mesogens that can form diverse assembly modes according to their conformations. In this study, dibenzoylbipyrrole derivatives bearing two aliphatic chains present at the para positions of the benzoyl units exhibited dynamically ordered behaviors due to their polarized conformations.…”

“…Conventional bent-core π-electronic mesogens, such as phenylene moieties linked by ester units, were used for chiral smectic assemblies with spontaneous polarization properties, leading to electric-field-responsive behaviors and ferroelectric materials. , As directly linked arene oligomers, dimers of five-membered π-systems, such as 2,2′-bipyrrole ( 1 ), have either C 2h symmetry ( anti conformation) or C 2v symmetry ( syn conformation) (Figure ), , which significantly affects their assembly modes. In our previous study, bipyrroles substituted with modified benzoyl units at the α-positions and possessing four or six aliphatic chains generated several assembled structures, such as liquid-crystalline mesophases, via intermolecular interactions . Notably, bipyrrole derivatives are considered unique mesogens that can form diverse assembly modes according to their conformations.…”

“…Following the previously reported synthetic procedures for 2a and derivatives, , benzoyl-substituted bipyrroles 2b and 3a – c , substituted with alkoxy (OC n H 2 n +1 ) moieties (Figure a), were synthesized in 64–92% yield using 1 and the corresponding dimethylbenzamides . According to theoretical geometry optimizations at the ωB97X-D/6-31+G­(d,p) level, the syn conformations in 2a , b , whose most stable configurations showed the carbonyl and pyrrole NH oriented in the same direction, were less stable than the corresponding anti conformations by only 1.03 and 1.01 kcal/mol, respectively (Figures b and S5).…”