UV Raman Analysis of the C:H Network Formed by Compression of Benzene

Abstract

A continuing challenge in understanding the linkage of unsaturated molecules to produce novel networks has been the analysis of the reaction products. Here we report a UV Raman spectroscopic analysis of the amorphous C:H (a-C:H) network formed by compression of benzene. The network contains both sp 2 -and sp 3 -bonded carbon, indicating that the aromaticity of some of the benzene rings must have been destroyed during the formation of the network. The Raman spectrum of the network resembles that of hydrogen-rich polymeric a-C:H. Analysis by means of UV Raman spectroscopy of a wide range of novel networks produced by compression of unsaturated molecules should be possible.

High-pressure polymorphism inl-threonine between ambient pressure and 22 GPa

“…One possibility is amorphisation, as seen for L-alanine at 15 GPa. 18 Cleavage of primary covalent bonds forms another potential route, exemplified by proton transfer in oxalic acid at 5.3 GPa, 82 or even wholescale decomposition into amorphous networks such as is seen for benzene 83,84 and pyridine. 85,86 Although the hydrogen bonds in L-threonine are substantially compressed up to 22.3 GPa, it is remarkable that their distances all find precedents at ambient pressure, and none of them can be described as 'abnormally short' (Fig.…”

Pressure-Induced Polymerization: Addition and Condensation Reactions

“…As important building blocks for PIP, aromatic compounds also attract continuously attentions. Since the 1980s, benzene (C 6 H 6 ), as the proto model of aromatic systems, has been systematically explored in the high-pressure research [35][36][37][38][39][40][41][42][43][44][45]. In recent years, through optimizing the synthetic conditions (a slow compression/decompression rate), one-dimensional sp 3 carbon nanothreads were identified from the sample recovered from compressing C 6 H 6 at room temperature [46,47].…”

From Molecules to Carbon Materials—High Pressure Induced Polymerization and Bonding Mechanisms of Unsaturated Compounds

“…The recovered products are white solid and become orange, red and finally black when heated [101]. Several techniques including Raman and IR spectroscopy were explored to investigate the product, which shows it is an amorphous C:H network containing both sp 2 and sp 3 -bonded carbon [102] and the aromaticity of the benzene ring was destroyed. This process mainly takes place during the decompression process, and radical species are contained in the reaction [100].…”