2
$\begingroup$

I am just about to start my senior project synthesis of PbS quantum dots and we ordered the wrong lead acetate. The method calls for lead (II) acetate and we got lead (IV) acetate. If we use the lead (IV) acetate will our synthesis be contaminated and not work or can we still use that chemical with two extra acetates attached?

$\endgroup$
  • $\begingroup$ Perhaps it's possible to turn the lead(IV) into lead(II) quantitatively with a mild reducing agent before you actually start the quantum dot syntheses? $\endgroup$ – Nicolau Saker Neto Feb 25 '14 at 22:38
3
$\begingroup$

You might run into problems. $\ce{Pb(OAc)4}$ is a pretty strong oxidant!

What will be your sulfide source? Are you sure that it isn't oxidized these conditions?

Edit 1

At least N,N'-diarylthioureas are efficiently desulfurized by lead tetraacetate and furnish ureas (and sulfur) via a carbodiimide intermediate, see Bull.Chem. Soc. Jpn., 1984, 57, 315-316.

Edit 2 If you don't mind a personal advice: I wouldn't want to add complexity to the protocol just to maneuver around problems (and create others) I wouldn't have if I were using the right starting materials in the first. (The German term for that is verschlimmbessern, which translates to something like disimprove).

| improve this answer | |
$\endgroup$
  • $\begingroup$ Sulfur is coming from a sulfurea/thiourea solution. The other reagents used are SDS CTAB as stabilizing agents and EDTA as a chelating agent to disperse Pb. Could adding a base such as aqua ammonia stabilize the excess acetate? $\endgroup$ – user4505 Feb 25 '14 at 21:48
  • $\begingroup$ In the present procedure aqua ammonia is already used in the preparation of the reaction mixture of water EDTA, SDS, and CTAB before the lead and sulfur precursors are added. the aqua ammonia is used to change the pH to 10 because EDTAs ligand formation is pH dependent and needs to be at a high pH around 10 for the fully deprotonated EDTA4− form to be prevalent. Does this make a difference now? $\endgroup$ – user4505 Feb 25 '14 at 22:52
  • $\begingroup$ You would still have the wrong oxidation state, isn't it? I know that Pb(II) does form complexes with EDTA, what about Pb(IV)? I have no idea. $\endgroup$ – Klaus-Dieter Warzecha Feb 25 '14 at 23:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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