Dynamic or undynamic chirality generated by helical arrangement of a shape-persistent ring and rod doubly bridged in a molecule

Abstract

We synthesized molecular assemblies of a ring and rod that were covalently bound in a molecule. The bridged components were helically arranged in a threaded or unthreaded form to show unique chiroptical properties based on shape-persistent m-phenylacetylene rings with six, five and four units and phenylene-ethynylene rods.

Chiral diversification through the assembly of achiral phenylacetylene macrocycles with a two-fold bridge

“…A model macrocycle 13 is composed of two halves of a [6]PA sequence that are doubly-bridged, and was used for monitoring complexation by 1 H NMR spectroscopy, since most protons were well-assigned. Chiral ditopic guests ( R , R )- 14 and ( S , S )- 14 were used as an external chiral source 16. They could be captured by the formation of hydrogen bonds at terephthalamide bridges (Fig.…”

“…We have been interested in a design strategy to provide multiple chiral structures through the assembly and double-bridging of achiral components 14–16. Here, we used phenylacetylene macrocycles (PAMs)17 as achiral components for the creation of multiple chiral molecules.…”

SESIUM KLORIDA (CsCl) : TRANSPORT ION DALAM LARUTAN

“…Waktu bagi bola tersebut untuk jatuh antara dua tanda diukur dengan teliti dan diulangi beberapa kali. Viskositas cairan dihitung dengan rumus : f = 6 π η r T (45) dimana f : gaya tahan η : viskositas r : jari-jari bola v : kecepatan Pada kesetimbangan gaya ke bawah (mm o )g = f, sehingga 6 π η r v = (m-m o ) g (46) Dengan m : masa bola logam mo : massa cairan yang dipindahkan oleh bola logam g : konstanta…”

A Chiral [3]Rotaxane Comprising Achiral Bis-macrocyclic and Dumbbell-Shaped Components

“…The induction of other chiral rotaxane structures has been studied recently. Katoono and Suzuki arranged the macrocyclic and axle components of a [1]­rotaxane-type structure in a molecularly chiral manner . Furthermore, we have synthesized a helically chiral [2]­rotaxane from highly symmetrical macrocyclic and axle components; two-point interlocking resulted in a helical conformation of the axle component in this [2]­rotaxane …”

“…Katoono and Suzuki arranged the macrocyclic and axle components of a [1]rotaxane-type structure in a molecularly chiral manner. 11 Furthermore, we have synthesized a helically chiral [2]rotaxane from highly symmetrical macrocyclic and axle components; 12 two-point interlocking resulted in a helical conformation of the axle component in this [2]rotaxane. 13 In this paper, we report a new mode of combining dumbbellshaped and macrocyclic components to generate chirality in a [3]rotaxane.…”