benzene ring


Also found in: Dictionary, Thesaurus, Medical, Financial.

benzene ring

[′ben‚zēn ‚riŋ]
(organic chemistry)
The six-carbon ring structure found in benzene, C6H6, and in organic compounds formed from benzene by replacement of one or more hydrogen atoms by other chemical atoms or radicals.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Aromatic region of the 1H-NMR spectrum (Table-1) of 2 showed two doublets at I' 7.30 (4H, J = 8.4 Hz) and 7.08 (4H, J = 8.4 Hz), which could be attested for two p-substituted benzene rings that revealed a symmetrical dimeric nature of 2.
In the previous section, the Raman stretching frequency of the bridging imidazole was used to reconcile the opposing changes in electronic density across the imidazole ring, and by association, the effect of the functional group changes on the benzene ring. However, in the case of the terminal group change, significant electronic and vibrational effects were observed such as the correlation of stokes shift with luminescence yield which have been absent for the regioisomers.
According to [sup.1]H NMR data, there exist an H signal on symmetrical spaces of benzene ring including [[delta].sub.H] 6.93 (2H, s) and double-bond signals [[delta].sub.H] 7.72 ([sup.1]H, d, J = 15.8) and [[delta].sub.H] 6.44 ([sup.1]H, d, J = 15.8), indicating that the double bonds possess trans configuration.
Although Robb's group had calculated this system by using CASSCF, the overlaps of ethylene moiety and benzene ring in synchronous and asynchronous mode were neglected.
Based on the solution P concentrations, it appears that benzoic and cinnamic acids behave as distinct groups, with the key differences in their structures being the distance of the carboxyl group from the benzene ring and the inclusion of a double-bond in the carboxyl side chain, both of which may influence their ability to form stable complexes with P in solution.
Environmental Protection Agency (EPA) and other regulatory agencies to identify diesters of orthophthalic acid, also called simply phthalic acid, an aromatic dicarboxylic acid in which the two carboxylic acid groups are located on adjacent carbons (positions 1 and 2) in the benzene ring. Both di-n-butyl phthalate (DBP) and di-(2-ethyl-hexyl) phthalate (DEHP) are examples of such phthalates; these phthalates are chemically and toxicologically distinct from diesters of isophthalic or terephthalic acids, which are not considered to be true "phthalates," as defined by the U.S.
The predominant isomer found in the body is alpha-tocopherol, which has three methyl groups in addition to the hydroxyl group attached to the benzene ring. The diet of animals is comprised of different proportions of tocopherol isomers and specific alpha-tocopherol-binding proteins are responsible for retention of this isomer in the cells and tissues of the body.
In IR spectrometer, the following absorption peaks were observed: at 3300 c [m.sup.-1] corresponding to the stretching vibration absorption of N-H; at 1570 and 1480 c [m.sup.-1] corresponding to the stretching vibration absorption peaks of C=C which belong to the quinone- and benzene rings, respectively; at around 1300 c [m.sup.-1] corresponding to the stretching vibration of C-N in the benzene ring; at around 1140 and 810 c [m.sup.-1] corresponding to the plane bending vibrations of C-H which belong to quinone- and benzene rings, respectively.
was found to proceed with difficulty due to the simultaneous presence of a substituent in the [N.sup.1] (the nitrogen connected directly with the benzene ring) and the ortho-position of the phenylhydrazone as in this experiment, as shown in the following example (Fig.
The 1 H-NMR spectrum exhibited 3 doublets at d 7.45 (J=1.8), 7.40 (J=1.8) and 7.11 (J=1.8) indicating the presence of a trisubstituted benzene ring with meta coupled H's.
Like Kekule's apocryphal dream of the tail-biting serpent and the benzene ring (3), I was overcome, so to speak, by a flash of clarity that I might electromotively transport proteins out of an unfixed gel directly onto nitrocellulose sheets in a protein gel-destaining chamber I used almost every day.