Neocuproine Property

Melting point:

159-164 °C

Boiling point:

337.46°C (rough estimate)

Density 

1.1345 (rough estimate)

refractive index 

1.6152 (estimate)

RTECS 

SF8380000

storage temp. 

Keep in dark place,Sealed in dry,Room Temperature

solubility 

methanol: 0.1 g/mL, clear

form 

crystalline

pka

6.01±0.30(Predicted)

color 

white to beige

Water Solubility 

slightly soluble

Sensitive 

Light Sensitive

Merck 

6449

InChIKey

IYRGXJIJGHOCFS-UHFFFAOYSA-N

CAS DataBase Reference

484-11-7(CAS DataBase Reference)

NIST Chemistry Reference

1,10-Phenanthroline, 2,9-dimethyl-(484-11-7)

EPA Substance Registry System

1,10-Phenanthroline, 2,9-dimethyl- (484-11-7)

Safety

Hazard Codes 

Xi,Xn

Risk Statements 

36/37/38-20/21/22-22

Safety Statements 

26-36/37/39-36-24/25

WGK Germany 

3

TSCA 

Yes

HS Code 

29339990

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P405Store locked up.

Neocuproine Chemical Properties,Usage,Production

Chemical Properties

OFF-WHITE TO VERY PALE YELLOW CRYSTALLINE POWDER

Uses

Due to the steric hindrance of the methyl groups attached to the carbon atoms adjacent to the nitrogen donor atoms of phenanthroline, the reagent does not give the low spin vivid red complex characteristic of phenanthroline derivatives with iron(II). However, in the presence of reducing agents it reacts with copper to give a copper(I) complex of composition MA2 and of tetrahedral symmetry. This chelate is insoluble in water and can be extracted by chloroform in which the absorption maximum of the complex appears at 457 nm. In this way the concentration of the complex can be measured. The method is suitable for the determination of copper in iron, manganese and vanadium ores even in the presence of aluminium, germanium, titanium and silicon.
Neocuproine is today considered one of the most selective reagents. Unfortunately, it is rather expensive. 2,3-bis-(2-pyridyl)quinoxaline, prepared by Belcher et al. by condensation of o-diketone, 2,2'-dipyridyl and 0-phenylenediamine(44) contains the functional grouping characteristic of cuproine; it is quite suitable for the determination of copper and it is cheap. Starting with various substituted o-phenylene-diamines Belcher synthesized 25 different quinoxaline derivatives, of which 2,3-bis-[2-(-methyl)-pyridyl)]quinoxaline proved to be identical with neocuproine as regards analytical selectivity. Besides copper, titanium(III) is the only metal ion which gives a colour reaction with the reagent. However, the coloured titanium(III) complex is formed only at lower pH and hence it does not interfere with the determination of copper. The copper complex of the reagent can be extracted quantitatively with isopentyl alcohol usually as a perchlorate ion pair.

Uses

Neocuproine is a phenanthroline based metal ion chelating agent.

Definition

ChEBI: A member of the class of phenanthrolines that is 1,10-phenanthroline bearing two methyl substituents at positions 2 and 9.

Purification Methods

Purifiy it as the hemihydrate by crystallisation from water and as the anhydrous base from *benzene. [Beilstein 23/8 V 527.]