Background and Originality Content

Chirality has been widely employed in the design of novel nanomolecular carbon structures in the fields of organic chemistry and material science.^1-3 Chiral macrocycles, in particular, offer several advantages, such as a rigid backbone enabling a stable chiral conformation, a terminal-less structure enabling excited states to spread across the whole molecule, and a cavity capable of accommodating guest molecules. However, the limited expansibility and tedious chiral introduction of these larger carbon structures restrict their wider application despite interest in their precise organic synthesis.^{4, 5} Consequently, the translation of molecular chirality into nanoscale chirality has been a subject of intense current research activity. Nanogrids, an emerging area of chiral carbon nanostructures, are powerful square carbon nanomaterials with edges and vertices, and their extraordinary expandable skeleton allows for constructing complex covalent nanoarchitectures.⁶Recently, a series of novel chiral nanogrids, including windmill-type,⁷ diamond-type,⁸ladder-type and drawing hands-type,^{9, 10} have been synthesized using Friedel-Crafts gridization. Our studies have demonstrated the potential of ordered chiral nanogrids for stereoregular organic nanopolymers applications.^{10, 11} The use of nanogrids and gridization in constructing complex chiral nanoarchitectures may therefore translate into a powerful molecular installation nanotechnology.

Chirality is a ubiquitous phenomenon in nature, and is also prevalent in the world of chemistry, particularly in many organic compounds.¹² Axial chirality, one of the most important chiral types, has been studied for over a century.¹³ Axially chiral molecule have broad applications, including molecular sensing,¹⁴ chiral resolution,¹⁵ chiral assembly and chemical catalysis.^{16, 17} Three categories of axially chiral molecules can be identified: biaryl axially chiral molecules (biphenyls, binaphthylenes and heterocycles),¹⁸ olefin axially chiral molecules (dienes, aromatic hydrocarbons and cycloalkanes) and spiro axially chiral molecules.^{19, 20} Of these, biaryl axially chiral molecules, particularly 2,2’-disubstituted derivatives of 1,1’-binaphthyl, are a versatile class of compounds that have found applications in many areas of chemistry and material.²¹ The robust configurational stability of binaphthyl derivatives in a broad range of conditions,²² combined with their tunable chiral dihedral angle, makes them an ideal platform for transferring stereoinformation and exhibiting excellent optical properties.²³ Here, we propose a fascinating class of A-type nanogrids (AGs), which consist of difluorenyl biaromatic derivatives (green and blue, A2 synthons which represents two reaction sites) and thiophene derivatives (red, B2 synthons which represents two reaction sites, Figure 1). AGs with a tunable axial chiral dihedral angle can exhibit varying photoelectric properties. Furthermore, we anticipate that AGs can be synthesized through an ”A2+B2” Friedel-Crafts gridization (FCG) reaction. Our investigations revealed that FCG provides an effective strategy for