Vibrational spectra and conformational isomerism of calixarene building blocks: 2-benzylphenolPart IV. For Parts I–III see refs. 1–3.

2003 ◽  
Vol 1 (4) ◽  
pp. 714-719 ◽  
Author(s):  
Sergei Katsyuba ◽  
Alla Chernova ◽  
Reinhard Schmutzler
Keyword(s):  
Vibrational Spectra ◽  
Building Blocks ◽  
Conformational Isomerism

Flexible “piperazine–pyrazine” building blocks: conformational isomerism of “equatorial–axial” sites toward the constructions of silver(i) coordination chains

CrystEngComm ◽  
2010 ◽  
Vol 12 (11) ◽  
pp. 3388 ◽  
Author(s):  
Shu-Chun Hsu ◽  
Jing-Yun Wu ◽  
Chin-Fen Lee ◽  
Chung-Chou Lee ◽  
Long-Li Lai ◽  
...  
Keyword(s):  
Building Blocks ◽  
Conformational Isomerism

For1ation of Zeolites: A Molecular Description

1987 ◽  
Vol 111 ◽  
Author(s):  
Prabir K. Dutta ◽  
M. Puri ◽  
D. C. Shieh
Keyword(s):  
Raman Spectroscopy ◽  
Vibrational Spectra ◽  
Crystallization Process ◽  
Building Blocks ◽  
Monovalent Cations ◽  
Zeolite X ◽  
Zeolite Formation ◽  
Amorphous Aluminosilicate ◽  
Molecular Description

AbstractRaman spectroscopy of the solution, solid and gel phases present during crystallization of zeolite X was investigated. The vibrational data indicate that an amorphous aluminosilicate solid, composed primarily of four membered aluminosilicate rings is in contact with monomeric silicate ions during the prenucleation stages of the zeolite formation. No intermediate building blocks specific to zeolite X could be discerned from the vibrational spectra. The influence of a series of monovalent cations on the crystallization process was also examined, and a model of zeolite formation has been proposed.

scholarly journals Control of Dynamic sp3-C Stereochemistry

2021 ◽  
Author(s):  
Aisha Bismillah ◽  
Toby Johnson ◽  
Burhan Hussein ◽  
Andrew Turley ◽  
Ho Chi Wong ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Dynamic Properties ◽  
Building Blocks ◽  
Metal Coordination ◽  
Chiral Molecules ◽  
Conformational Isomerism ◽  
Configurational Change ◽  
Nitrogen Inversion ◽  
Intermolecular Reactions ◽  
Cope Rearrangements

Abstract Stereogenic sp3-hybridized carbon centres are fundamental building blocks of chiral molecules. Unlike dynamic stereogenic motifs, such as sp3-nitrogen centres or atropisomeric biaryls, sp3-carbon centres are usually fixed, requiring intermolecular reactions to undergo configurational change. Here, we report the internal enantiomerization of fluxional carbon cages and the consequences of their adaptive configurations for the transmission of stereochemical information. The sp3-carbon stereochemistry of the rigid tricyclic cages is inverted through strain-assisted Cope rearrangements, emulating the low-barrier configurational dynamics typical for sp3 nitrogen inversion or conformational isomerism. This dynamic enantiomerization can be stopped, restarted, or slowed by external reagents, while the configuration of the cage is controlled by neighbouring, fixed stereogenic centres. As part of a phosphoramidite–olefin ligand, the fluxional cage acts as a conduit to transmit stereochemical information from the ligand while also transferring its dynamic properties to chiral-at-metal coordination environments, influencing catalysis and ligand exchange energetics.

Vibrational spectra and conformational isomerism of 2-phenoxy-5,6-benz-1,3,2-dioxaphosphepins

1989 ◽  
Vol 38 (4) ◽  
pp. 757-762
Author(s):  
R. R. Shagidullin ◽  
I. Kh. Shakirov ◽  
R. P. Arshinova ◽  
R. A. Kadyrov
Keyword(s):  
Vibrational Spectra ◽  
Conformational Isomerism

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Sign in / Sign up

Export Citation Format

Share Document