Homologous Ladder Cyclohexasilanes.
Rebekka S Klausen1, Fan Fang2, Andrew Molino1
1Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland, 21218, USA.
Angewandte Chemie (International Ed. in English)
|June 28, 2025
Summary
Researchers synthesized novel ladder cyclohexasilanes with fused rings. The study reveals how reaction conditions influence ring configuration and how additional rings shift light absorption properties.
Area of Science:
- Organosilicon Chemistry
- Materials Science
- Photophysics
Background:
- Ladder silanes are silicon-based compounds with unique structural properties.
- Controlling stereochemistry in fused ring systems is crucial for tuning material characteristics.
- Understanding structure-property relationships in silicon cages is key for developing new materials.
Purpose of the Study:
- To synthesize novel ladder cyclohexasilanes with up to three fused rings.
- To investigate the influence of reaction conditions (kinetic vs. thermodynamic control) on ring fusion configuration.
- To explore the relationship between the number of fused rings and light absorption properties.
Main Methods:
- Synthesis of five new ladder cyclohexasilane derivatives.
- Utilized a coupling reaction between a 1,4-dipotassiooligosilyl dianion and cyclohexasilane.
- Employed combined experimental and computational (theoretical) studies for structural and photophysical analysis.
Main Results:
- Successfully synthesized bi- and tricyclic ladder cyclohexasilanes.
- Demonstrated that kinetic control favors cis configuration, while thermodynamic control yields trans configuration.
- Computational studies indicated a bathochromic shift in light absorption with increasing rings in the trans-diastereomeric series.
Conclusions:
- The stereochemical outcome of ladder cyclohexasilane annulation is controllable via reaction conditions.
- The number of fused rings significantly impacts the electronic properties, specifically light absorption.
- These findings provide insights into the synthesis and properties of complex organosilicon structures.
More Related Videos
09:34Synthesis of Information-bearing Peptoids and their Sequence-directed Dynamic Covalent Self-assembly
Published on: February 6, 2020
7.5K
09:35Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
11.6K
Related Concept Videos
02:02Chair Conformation of Cyclohexane
15.4K
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
15.4K
02:28Cycloalkanes
13.3K
Cycloalkanes are saturated cyclic hydrocarbons with carbon atoms arranged in the form of rings. They have two fewer hydrogen atoms than the corresponding acyclic alkane; therefore, their general formula is CnH2n. The structural formulas of cycloalkanes are simplified using the line-angle representation. The regular polygons are used to represent the cycloalkane rings, with each side representing a carbon-carbon bond.
The IUPAC nomenclature of cycloalkanes follows similar rules that apply to...
The IUPAC nomenclature of cycloalkanes follows similar rules that apply to...
13.3K
02:11Conformations of Cyclohexane
13.2K
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
13.2K
02:37Disubstituted Cyclohexanes: cis-trans Isomerism
12.4K
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
12.4K
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
10.8K
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
10.8K
02:29Conformations of Cycloalkanes
12.3K
Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3 hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that...
12.3K