ONeill - 3-5-2021 at 22:58
Hello mad scientist,
I hope this si the right subsection of the discussion board for my question.
So in coordination compounds (with metal = M) you sort the ligands (e.g., A, B, C) by the alphabet:
[MABC]
When you have a ligand with an atom that has an element symbol that is longer than one letter, the element with the single letter element symbol goes
first, e.g., a single carbon (hypothetically) comes before chlorido:
[M C Cl] added spaces to make it more visible
But how is it with abbrevations such as Cp? I am aware that IUPAC discourages abbrevations in general, but Cp is so common in the literature. Is
titanocene dichloride [Ti (Cp)2 Cl2] or [Ti Cl2 (Cp)2]
I tried to find the answer in the Red Book from IUPAC, but was not successful. Maybe the smart members here can give me some advice. I appreciate your
time.
Many thanks,
ONeill
njl - 4-5-2021 at 05:32
For some reason I always see Cp first as in (Cp)2[TiCl2]. Whether or not that's correct, I don't know.
DraconicAcid - 4-5-2021 at 08:41
Ti(Cp)2Cl2 or Cp2TiCl2. (Cp)2[TiCl2] would suggest that the cyclopentadienyls are cations, and not coordinated to the TiCl2 anion. Chemists who
write it that way should be slapped. Square brackets have a defined meaning, people!