Preventing formation of copper (II) hydroxide in alkaline solution

All I was hinting at is that if the copper gets complexed by ammonia AFTER it first precipitated, finding a complexing agent capable of complexing copper to prevent precipitation in high pH shouldn't be a problem.

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Is there an ideal stoichiometric ratio for this? Or simply excess?

Whether you need an excess or not depends on the complex stability constant. But in general using small excess - if it doesn't interfere - would be a good idea, it keeps you on the safe side.

In technical application EDTA, Quadrol or tartrate is in use. Application electroless copper bathes for electroless plating.

But this will go in this way, that during adding the ammonia copper hydroxide precipitates and dissolve later on. The other mentioned complex agents prevent this phenomina.

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In technical application EDTA, Quadrol or tartrate is in use. Application electroless copper bathes for electroless plating.

Also, following the tartrate suggestion - would really most dicarboxylic acids work for this application? Or do the hydroxyl groups help complex the metal center in addition to the carboxylate groups?

Thanks for the insight you guys. Borek, I'd like to avoid the addition of any complexing agents that contain N-atoms as they contaminate my solution. Tartrate may be a good starting point as there it is only C, O.

Is there an ideal stoichiometric ratio for this? Or simply excess?

Have you ever added ammonia to copper(II) solution?