Substituent effect on inter-ring interaction in paracyclophanes

Abstract

The theoretical calculations, namely multipole-derived charge analysis, quantum theory of atom in molecules, and nonbonding interaction (NCI), were performed for [2.2]paracyclophanes, [2.2]paracyclophane-7,9-dienes, and [3.3]paracyclophanes optimized at B3LYP/6-311++G** level, including dispersion correction. The substituent effect of the electron donor N(Me) 2 and electron acceptor NO 2 group and the influence of the length of bridges joining the aromatic ring on aromatic ring interaction energy (AIE) and strain energy were discussed. The local and electrostatic character of the substituent effect in paracyclophanes was shown. The presence of the weak orbital through-space C•••C interaction between the [3.3]paracyclophane ring and weak CH•••O hydrogen bonds between the substituents in the different rings was shown.

Thiourea Organocatalysts as Emerging Chiral Pollutants: En Route to Porphyrin-Based (Chir)Optical Sensing

“…Such low electron density is characteristic of a weak and unstable ππ interaction in 1a•P3. [108,109] order stabilization energies of 2.90 kcal mol −1 , and, from the π-π stacking, the secondorder stabilization energy was 7.78 kcal mol −1 for 1a•P3 complex (Figure 6 and Table S32 in the Supplementary Materials) [110]. The Zn⋯N second-order stabilization energies were 143.64 kcal mol −1 (Table S32 in the Supplementary Materials).…”

“…Such low electron density is characteristic of a weak and unstable π-π interaction in 1a•P3. [108,109]. The QTAIM approach also reveals the presence of weak interactions between H•••C, H•••F, and F•••C atoms in the aryls of the host-guest pair.…”

Synthesis of New Planar-Chiral Linked [2.2]Paracyclophanes-N-([2.2]-Paracyclophanylcarbamoyl)-4-([2.2]Paracyclophanylcarboxamide, [2.2]Paracyclophanyl-Substituted Triazolthiones and -Substituted Oxadiazoles

“…Compounds comprising the −NH–NH–C=O moiety are known as acylhydrazide linkers. More specifically, acylhydrazide-based compounds have shown antioxidant activities [ 1 , 2 , 3 , 4 ]. Hydrazides and carbohydrazides have been described as useful building blocks for the assembly of various heterocyclic rings [ 5 ].…”

What Is the Main Feature Distinguishing the Through-Space Interactions in Cyclophanes from Their Aliphatic Analogues?

“…The aim of our present study is a comparison of the through-space interaction and some through-bond interactions in typical cyclophanes with two benzene rings where one benzene ring is joined with an aliphatic unit, [ n ]­cyclophanes and araliphanes as well as aliphatic analogues of cyclophanes where both benzene rings have been replaced with alicyclic ones. As the “reference system”, we have taken a typical cyclophane, widely investigated I [2.2]­paracyclophane − (Scheme ). The other typical cyclophanes analyzed are II metapara[2.2]­cyclophane, anti -[2.2]­metacyclophanes IIIa and IIIb , ,, and syn -[2.2]­metacyclophane IIIc .…”

“…We have undertaken investigation of the geometry, atomic charges, mobility of the electrons in the molecule, energy of the interactions between the benzene ring and aliphatic unit, steric strain, and the attractive and repulsive through-space interactions for compounds presented in Scheme . The typical cyclophanes I – III − and [ n ]­cyclophanes VI – IX , were the object of previous investigation, but in order to perform a reliable comparative study of the different groups of cyclophanes, analysis of properties using the same method of calculation seems to be desirable. The crystal structure of compounds V, X , and XI and the derivative of XII were known, but the intramolecular interactions have not been an object of investigations up to now.…”