| 词条 | Newman projection | |||||||||
| 释义 |
A Newman projection, useful in alkane stereochemistry, visualizes the conformation of a chemical bond from front to back, with the front atom represented by a dot and the back carbon as a circle. The front carbon atom is called proximal, while the back atom is called distal. This type of representation clearly illustrates the specific dihedral angle between the proximal and distal atoms.[1] This diagram style is an alternative to a sawhorse projection, which views a carbon-carbon bond from an oblique angle, or a wedge-and-dash style, such as a Natta projection. These other styles can indicate the bonding and stereochemistry, but not as much conformational detail. This projection is named after American chemist Melvin Spencer Newman, who introduced it in 1952 as partial replacement for Fischer projections, which are unable to represent conformations and thus conformers properly.[2][2] A Newman projection can be used to visualize any sort of bond, not just a single bond between carbons of an alkane. For example, it can be used to study cyclic molecules,[3] such as the chair conformation of cyclohexane:
See also{{commons category|Newman projection}}
References1. ^{{Cite journal|last=Moss|first=GP|date=1996-01-01|title=Basic terminology of stereochemistry (IUPAC Recommendations 1996)|url=https://www.degruyter.com/view/j/pac.1996.68.issue-12/pac199668122193/pac199668122193.xml|journal=Pure and Applied Chemistry|volume=68|issue=12|pages=2193–2222|doi=10.1351/pac199668122193|issn=1365-3075}} 2. ^Newman, MS. Record. Chem. Progr. (Kresge-Hooker Sci. Lib.) 1952, 13, 111 3. ^1 {{Cite journal|last=Newman|first=MS|date=1955|title=A notation for the study of certain stereochemical problems|journal=Journal of Chemical Education|volume=32|issue=7|pages=344|doi=10.1021/ed032p344|issn=0021-9584}} 1 : Stereochemistry |
|||||||||
| 随便看 |
|
|||||||||
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。