I’ve been trying to find a method to perform a spectrophotometric analysis to determine lead concentration (on the ppm level). This would require some chelator capable of forming a coloured complex with lead in the aqueous phase.

Fe(II) ion can bind to o-phenanthroline to form an orange colour (with deeper hues based on the present concentration of iron irons). I was wondering if lead(II) can too complex in the same way.

Note: The source of lead is $\ce{Pb(NO3)2}.$ This means some nitrate ions will be present in solution after dissociation of this chemical in water.


1 Answer 1


Yes, there are numerous known lead(II) o-phenanthroline complexes with thiocyanate, perchlorate and bulkier organic ligands. As for nitrate, Bytheway et al. [1] reported synthesis (from lead(II) nitrate in methanol) and crystal structure of bis((1,10-phenanthroline)-(nitrato-O,O'))-lead(II):

rystal structure of bis((1,10-phenanthroline)-(nitrato-O,O'))-lead(II)
Figure 1. crystal structure of $\ce{[(phen)2Pb(NO3)2]}$ (CCDC: 1246661, CSD: RAQMAX).

Unfortunately, there is no UV-Vis/NIR spectra available. Harrowfield et al. [2, p. 1030] reported that the crystals are colorless, which likely eliminates visible region of detection.


  1. Bytheway, I.; Engelhardt, L.; Harrowfield, J.; Kepert, D.; Miyamae, H.; Patrick, J.; Skelton, B.; Soudi, A.; White, A. Lewis-Base Adducts of Lead(II) Compounds. XIII. Synthetic, Structural and Theoretical Studies of Some 2:1 Adducts of 1,10-Phenanthroline With Lead(II) Oxoanion Salts. Aust. J. Chem. 1996, 49 (10), 1099. DOI: 10.1071/CH9961099.
  2. Harrowfield, J.; Miyamae, H.; Skelton, B.; Soudi, A.; White, A. Lewis-Base Adducts of Lead(II) Compounds. VII. Synthetic and Structural Studies of Some 1:1 Adducts of Linear Polyamines With Lead(II) Nitrate. Aust. J. Chem. 1996, 49 (10), 1029. DOI: 10.1071/CH9961029.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.