Chiral Recognition of Hexahelicene on a Surface via the Forming of Asymmetric Heterochiral Trimers

Abstract

Chiral recognition among helical molecules is of essential importance in many chemical and biochemical processes. The complexity necessitates investigating manageable model systems for unveiling the fundamental principles of chiral recognition at the molecular level. Here, we reported chiral recognition in the self-assembly of enantiopure and racemic hexahelicene on a Au(111) surface. Combing scanning tunneling microscopy (STM) and atomic force microscopy (AFM) measurements, the asymmetric heterochiral trimers were observed as a new type of building block in racemic helicene self-assembly on Au(111). The intermolecular recognition of the heterochiral trimer was investigated upon manual separation so that the absolute configuration of each helicene molecule was unambiguously determined one by one, thus confirming that the trimer was “2+1” in handedness. These heterochiral trimers showed strong stability upon different coverages, which was also supported by theoretical calculations. Our results provide valuable insights for understanding the intermolecular recognition of helical molecules.

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…Articles [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] can be attributed to the first of the thematic areas indicated in the PCCP Section, and the distribution of these articles into the above categories is presented in Table 2 . As it can be seen, of the four types of articles established by the magazine’s standards ( Reviews , Originals, Communications , Editorials ), only the first two are presented here.…”

“…The first of them [ 1 ], dated early November 2018, was devoted to the study of the intermolecular interactions that contribute to the stability of the tear film; it was the first to study the conformation of the hydrocarbon chain and rheology of meibum from babies. Articles [ 2 , 3 , 6 ] can also be referred to the biology-medical direction in the Thematic Area 1; the first two of them are devoted to the problem of the so-called molecular recognition of organic compounds, and the third to the specific interaction of peptide molecules in aqueous solutions. The most significant place in this thematic area belongs to works in which mesoporous micro- and nano-spherical particles, and the intermolecular forces associated with them, appear as the object of research [ 12 , 15 , 16 , 17 , 20 ].…”

“…This area is the largest in terms of the number of related publications and includes 91 articles, namely [ 1 , 2 , 3 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 ,…”

Conceptions of Vibrational Signatures Based on Chiral/Helical Functionalized Helicenes Nanostructures: Analyzed of Normal and Identical Modes

“…Helicene molecules, which are made of ortho-fused rings, have unique properties combining the electron delocalization and helicity [1][2][3][4] . Therefore, they exhibit chiroptical properties, such as optical rotation [5][6][7] and specific electronic circular dichroism bands 8,9 . In addition, their electronic responses, chirality also leads to remarkable vibrational properties, which can be probed using Vibrational Circular Dichroism (VCD) and Vibrational Raman Optical Activity (VROA) spectroscopies 10,11 .…”

On-Surface Mechanochemistry Synthesis of Non-Alternant Non-Benzenoid Aromatic Compounds Containing 4 to 8-Membered Rings

“…The conversion of a [7]helicene to planar coranulene derivative on Ag(111) surface (18) or the transformation of helical compounds with azuleno moieties to planar species with fulvaleno segments on Cu(001) surface (19) demonstrates such surface-induced reactions. Although several reports on the deposition of helical compounds on metal surfaces have been published (20)(21)(22), their further transformations have not been studied yet in detail and, thus, the above-mentioned studies (18,19) represent unique reports on the planarization of helical compounds in this potentially attractive but hitherto unexplored area.…”