View source for Phenanthroline

{{chembox
| Watchedfields = changed
| verifiedrevid = 265740134
|   Name = Phenanthroline
|   ImageFile = 1,10-phenanthroline.svg
<!-- | ImageSize = 200px -->
|   ImageName = 1,10-phenanthroline
|   IUPACName = 1,10-phenanthroline
| Section1 = {{Chembox Identifiers
|   CASNo = 66-71-7
|    CASNo_Ref = {{cascite}}
|   SMILES = c1ccnc3c1ccc2cccnc23
|   RTECS = SF8300000
  }}
| Section2 = {{Chembox Properties
|   Formula = C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>
|   MolarMass = 180.21 g/mol
|   Appearance = colourless crystals
|   Density = 1.31 g/cm<sup>3</sup>
|   Solubility = moderate
|   Solvent = other solvents
|   SolubleOther = acetone
|   MeltingPt = 117 °C
|   BoilingPt =
|   pKb = 
  }}
| Section7 = {{Chembox Hazards
|   ExternalMSDS =
|   MainHazards = mild neurotoxin, strong nephrotoxin, and powerful diuretic
|   RPhrases = {{R25}}, {{R50/53}}
|   SPhrases = {{S45}},{{S60}},{{S61}}
  }}
| Section8 = {{Chembox Related
|   OtherCpds = [[2,2'-bipyridine]]<br />ferroin<br />[[phenanthrene]]
  }}
}}

'''Phenanthroline''' ('''phen''') is a [[heterocyclic]] [[organic compound]]. As a bidentate [[ligand]] in [[coordination chemistry]], it forms strong complexes with most metal ions.  In terms of its coordination properties, phen is similar to [[2,2'-bipyridine]] (bipy).  

==Synthesis==
Phenanthroline may be prepared by two successive [[Skraup reaction|Skraup reactions]] of [[glycerol]] with [[o-Phenylenediamine|''o''-phenylenediamine]], catalyzed by [[sulfuric acid]], and an oxidizing agent, traditionally [[Aqueous solution|aqueous]] [[arsenic acid]] or [[nitrobenzene]].<ref>{{cite journal | author = B. E. Halcrow, W. O. Kermack | journal = [[J. Chem. Soc.]] | pages = 155–157 | year = 1946 | doi = 10.1039/jr9460000155 | title = 43. Attempts to find new antimalarials. Part XXIV. Derivatives of o-phenanthroline (7 : 8 : 3′ : 2′-pyridoquinoline)}}</ref>  Dehydration of [[glycerol]] gives [[acrolein]] which condenses with the [[amine]] followed by a cyclization.

==Peptidase inhibitor==
1,10-Phenanthroline is an [[enzyme inhibitor|inhibitor]] of [[metallopeptidase]]s, with one of the first observed instances reported in carboxypeptidase A.<ref>{{Cite journal | doi = 10.1021/bi00908a006 | author = Felber, JP, Coombs, TL & Vallee, BL | title = The mechanism of inhibition of carboxypeptidase A by 1,10-phenanthroline | journal = Biochemistry | year = 1962 | volume = 1 | pages = 231–238 | pmid = 13892106}}</ref> Inhibition of the enzyme occurs by removal and chelation of the metal ion required for catalytic activity, leaving an inactive apoenzyme. 1,10-Phenanthroline targets mainly zinc metallopeptidases, with a much lower affinity for calcium.<ref>{{cite journal | author = Salvesen, GS & Nagase, H | title = Inhibition of proteolytic enzymes | journal = Proteolytic enzymes: a practical approach, 2 edn | year = 2001 | volume = 1 | pages = 105–130}}</ref>

==Ferroin and analogues==
The complex [Fe(phen)<sub>3</sub>]<sup>2+</sup>, called "[[ferroin]]," is used for the [[spectrophotometry|photometric]] determination of Fe(II).<ref>Belcher, R. "Application of chelate Compounds in Analytical Chemistry" Pure and Applied Chemistry, 1973, volume 34, pages 13-27.</ref>  It is used as a [[redox]] [[redox indicator|indicator]] with [[standard potential]] +1.06 V.  The reduced ferrous form has a deep red colour and the oxidised form is light-blue.  Ferroin is used as a cell permeable [[Enzyme inhibitor|inhibitor]] for [[metalloprotease]]s in cell biology.

The pink complex [Ni(phen)<sub>3</sub>]<sup>2+</sup> has been resolved into its Δ and Λ isomers.<ref>{{cite journal | title = Resolution of the tris-(1,10-Phenanthroline)Nickel(II) Ion | author = [[George B. Kauffman]], Lloyd T. Takahashi | journal = [[Inorg. Synth.]] | year = 1966 | volume = 5 | pages = 227–232}}</ref>  The analogous [Ru(phen)<sub>3</sub>]<sup>2+</sup> has long been known to be bioactive.<ref>{{cite journal | author =F. P. Dwyer, E. C. Gyarfas, W. P. Rogers, J. H. Koch | title = Biological Activity of Complex Ions | journal = [[Nature (journal)|Nature]] | volume = 170 | pages = 190–191 | year = 1952 | doi = 10.1038/170190a0}}</ref>

==Related ligands==
In the related compound "bathophenanthroline," the 4 and 7 positions are substituted by [[phenyl]] groups.

==As an indicator for alkyl lithium reagents==
Alkyl lithium reagents form deeply colored derivatives with phenanthroline.  The alkyl lithium content of solutions can be determined by treatment of such reagents with small amounts of phenanthroline (ca. 1 mg) followed by titration with alcohols to a colourless [[endpoint (chemistry)|endpoint]].<ref>{{OrgSynth | author = Paul J. Fagan and William A. Nugent | title = 1-Phenyl-2,3,4,5-Tetramethylphosphole| collvol = 9 | collvolpages = 653| year = 1998 | prep = CV9P0653}}</ref>

[[Grignard reagents]] may be similarly titratred.<ref>{{cite journal | author =Ho-Shen Lin, Leo A. Paquette | title = A Convenient Method for Determining the Concentration of Grignard Reagents | journal = Synth. Commun. | volume = 24 | pages = 2503–2506 | year = 1994 | doi = 10.1080/00397919408010560}}</ref>

==References==
<references/>

==External Links==
* The [[MEROPS]] online database for peptidases and their inhibitors: [http://meropstest.sanger.ac.uk/cgi-bin/smi_summary?mid=J00150 1,10-Phenanthroline]


[[Category:Redox indicators]]
[[Category:Chelating agents]]
[[Category:Phenanthrolines]]

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[[fr:1,10-phénantroline]]
[[it:1,10-fenantrolina]]
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[[ja:フェナントロリン]]
[[pl:Fenantrolina]]
[[pt:Fenantrolina]]
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[[Category:2Fix]]