In organic chemistry, the phenyl group or phenyl ring is a cyclic group of atoms with the formula C6H5. Phenyl groups are closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group. Phenyl groups have six carbon atoms bonded together in a hexagonal planar ring, five of which are bonded to individual hydrogen atoms, with the remaining carbon bonded to a substituent. Phenyl groups are commonplace in organic chemistry. Although often depicted with alternating double and single bonds, phenyl groups are chemically aromatic and show nearly equal bond lengths between carbon atoms in the ring.
2 Structure, bonding, characterization 3 Preparation, occurrence, and applications 4 References 5 External links
Usually, a "phenyl group" is synonymous to C6H5– and is represented
by the symbol Ph or, archaically, Φ.
C6H6 + E+ → C6H5E + H+
where E+ (the "electrophile") = Cl+, NO2+, SO3. These reactions are called electrophilic aromatic substitutions.
Representative compounds containing phenyl groups
Phenylalanine, a common amino acid.
Biphenyl, consisting of two phenyl groups. The two rings tend not to be coplanar.
Phenyl groups are found in many organic compounds, both natural and synthetic (see figure). Most common among natural products is the amino acid phenylalanine, which contains a phenyl group. A major product of the petrochemical industry is "BTX" consisting of benzene, toluene, and xylene - all of which are building blocks for phenyl compounds. The polymer polystyrene is derived from a phenyl-containing monomer and owes its properties to the rigidity and hydrophobicity of the phenyl groups. Many drugs as well as many pollutants contain phenyl rings. One of the simplest phenyl-containing compounds is phenol, C6H5OH. It is often said the resonance stability of phenol makes it a stronger acid than that of aliphatic alcohols such as ethanol (pKa = 10 vs. 16–18). However, a significant contribution is the greater electronegativity of the sp2 alpha carbon in phenol compared to the sp3 alpha carbon in aliphatic alcohols. References
^ a b March, Jerry (1992). Advanced organic chemistry : reactions, mechanisms, and structure (4th ed.). New York: Wiley. ISBN 0-471-60180-2. ^ a b "Virtual Textbook of Organic Chemistry: Aromaticity". Michigan State University. http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/react3.htm ^ "phenyl: definition of phenyl in Oxford dictionary (American English) (US)". Retrieved 3 March 2016. ^ Hansch, Corwin.; Leo, A.; Taft, R. W. (1991-03-01). "A survey of Hammett substituent constants and resonance and field parameters". Chemical Reviews. 91 (2): 165–195. doi:10.1021/cr00002a004. ISSN 0009-2665. ^ Hameka, Hendrik F. (1987). "Computation of the structures of the phenyl and benzyl radicals with the UHF method". The Journal of Organic Chemistry. 52 (22): 5025–5026. doi:10.1021/jo00231a035. ISSN 0022-3263. ^ Silva, Pedro Jorge (2009). "Inductive and Resonance Effects on the Acidities of Phenol, Enols, and Carbonyl α-Hydrogens". The Journal of Organic Chemistry. 74 (2): 914–916. doi:10.1021/jo8018736. ISSN 0022-3263. PMID 19053615.
Media related to
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Only carbon, hydrogen and oxygen
Only one element apart from C, H, O
Disulfide Sulfone Sulfonic acid Sulfoxide Thial Thioester Thioether Thioketone Thiol
Selenol Selenonic acid Seleninic acid Selenenic acid
Isothiocyanate Phosphoramide Sulfenyl chloride Sulfonamide Thiocyanate
See also chemical classification, chemical nomenclature (inorganic, organic)