Phenanthroline
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| Names | |
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| IUPAC name
1,10-phenanthroline
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| Identifiers | |
66-71-7  |
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| 3D model (Jmol) | Interactive image |
| ChEBI | CHEBI:44975 |
| ChEMBL | ChEMBL415879 |
| ChemSpider | 1278 |
| DrugBank | DB02365 |
| ECHA InfoCard | 100.000.572 |
| RTECS number | SF8300000 |
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| Properties | |
| C12H8N2 | |
| Molar mass | 180.21 g/mol |
| Appearance | colourless crystals |
| Density | 1.31 g/cm3 |
| Melting point | 117 °C (243 °F; 390 K) |
| moderate | |
| Solubility in other solvents | acetone
ethanol |
| Acidity (pKa) | 4.86 (phenH+)[1] |
| Hazards | |
| Main hazards | mild neurotoxin, strong nephrotoxin, and powerful diuretic |
| R-phrases | R25, R50/53 |
| S-phrases | S45,S60,S61 |
| Related compounds | |
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Related compounds
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2,2'-bipyridine ferroin phenanthrene |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
Phenanthroline (phen) is a heterocyclic organic compound. It is a white solid that is soluble in organic solvents. It is used as a ligand in coordination chemistry, it forms strong complexes with most metal ions.[2]
Contents
Synthesis[edit]
Phenanthroline may be prepared by two successive Skraup reactions of glycerol with o-phenylenediamine, catalyzed by sulfuric acid, and an oxidizing agent, traditionally aqueous arsenic acid or nitrobenzene.[3] Dehydration of glycerol gives acrolein which condenses with the amine followed by a cyclization.
Coordination chemistry[edit]
In terms of its coordination properties, phen is similar to 2,2'-bipyridine (bipy) but binds metals more tightly since the chelating nitrogen donors are preorganized.
Many homoleptic complexes are known. Particularly well studied is [Fe(phen)3]2+, called "ferroin." It was used for the photometric determination of Fe(II).[4] It is used as a redox indicator with standard potential +1.06 V. The reduced ferrous form has a deep red colour and the oxidised form is light-blue.[5] The pink complex [Ni(phen)3]2+ has been resolved into its Δ and Λ isomers.[6] Copper(I) forms [Cu(phen)2]+, which is luminescent.[7][8]
Bioinorganic chemistry[edit]
The ferroin analogue [Ru(phen)3]2+ has long been known to be bioactive.[9]
1,10-Phenanthroline is an inhibitor of metallopeptidases, with one of the first observed instances reported in carboxypeptidase A.[10] 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.[11]
Related phen ligands[edit]
A variety of substituted derivatives of phen have been examined as ligands.[8] Neocuproine, 2,9-dimethyl-1,10-phenanthroline, is a bulky ligand. In "bathophenanthroline," the 4 and 7 positions are substituted by phenyl groups. The more electron-rich phenanthroline ligand is 3,4,7,8-tetramethyl-1,10-phenanthroline.[2]
As an indicator for alkyllithium reagents[edit]
Alkyllithium reagents form deeply colored derivatives with phenanthroline. The alkyllithium 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.[12] Grignard reagents may be similarly titrated.[13]
References[edit]
- ^ Durand, J., et al., "Long-Lived Palladium Catalysts for Co/Vinyl Arene Polyketones Synthesis: A Solution to Deactivation Problems", Chemistry – A European Journal 2006, volume 12, 7639-7651. doi:10.1002/chem.200501047
- ^ a b C.R. Luman, F.N. Castellano "Phenanthroline Ligands" in Comprehensive Coordination Chemistry II, 2003, Elsevier. ISBN 978-0-08-043748-4.
- ^ B. E. Halcrow; W. O. Kermack (1946). "43. Attempts to find new antimalarials. Part XXIV. Derivatives of o-phenanthroline (7 : 8 : 3′ : 2′-pyridoquinoline)". J. Chem. Soc.: 155–157. doi:10.1039/jr9460000155.
- ^ Belcher, R. "Application of chelate Compounds in Analytical Chemistry" Pure and Applied Chemistry, 1973, volume 34, pages 13-27.
- ^ Bellér, G. B.; Lente, G. B.; Fábián, I. N. (2010). "Central Role of Phenanthroline Mono-N-oxide in the Decomposition Reactions of Tris(1,10-phenanthroline)iron(II) and -iron(III) Complexes". Inorganic Chemistry. 49: 3968–3970. doi:10.1021/ic902554b. PMID 20415494.
- ^ George B. Kauffman, Lloyd T. Takahashi (1966). "Resolution of the tris-(1,10-Phenanthroline)Nickel(II) Ion". Inorg. Synth. 5: 227–232. doi:10.1002/9780470132395.ch60.
- ^ Armaroli, N., "Photoactive Mono- and Polynuclear Cu(I)-Phenanthrolines. A Viable Alternative to Ru(Ii)-Polypyridines?", Chemical Society Reviews 2001, volume 30, 113-124.doi:10.1039/b000703j
- ^ a b Pallenberg, A. J.; Koenig, K. S.; Barnhart, D. M., "Synthesis and Characterization of Some Copper(I) Phenanthroline Complexes", Inorg. Chemistry 1995, volume 34, 2833-2840. doi:10.1021/ic00115a009
- ^ F. P. Dwyer; E. C. Gyarfas; W. P. Rogers; J. H. Koch (1952). "Biological Activity of Complex Ions". Nature. 170 (4318): 190–191. doi:10.1038/170190a0. PMID 12982853.
- ^ Felber, JP, Coombs, TL & Vallee, BL (1962). "The mechanism of inhibition of carboxypeptidase A by 1,10-phenanthroline". Biochemistry. 1 (2): 231–238. doi:10.1021/bi00908a006. PMID 13892106.
- ^ Salvesen, GS & Nagase, H (2001). "Inhibition of proteolytic enzymes". Proteolytic enzymes: a practical approach, 2 edn. 1: 105–130.
- ^ Paul J. Fagan and William A. Nugent (1998). "1-Phenyl-2,3,4,5-Tetramethylphosphole". Org. Synth.; Coll. Vol., 9, p. 653
- ^ Ho-Shen Lin; Leo A. Paquette (1994). "A Convenient Method for Determining the Concentration of Grignard Reagents". Synth. Commun. 24 (17): 2503–2506. doi:10.1080/00397919408010560.
