Talk:Niobocene dichloride

Synthesis

Is anyone able to correct next equation, the second line in the synthesis of this mettalocene:

(C₅H₅)₄Nb + 2 HCl + 0.5 O₂ → [{C₅H₅)₂NbCl}₂O]Cl₂ + 2 C₅H₆

Please, at the moment only two chlorines enter the reaction, while four are coming out, as well as an extra niobium atom and some cyclopentadienes. As I have no access to a chemical library I am only able to note the discrepancy, not to correct it properly.T.vanschaik (talk) 15:44, 13 May 2024 (UTC)

That equation also has a simple typo in it: unbalanced parens around the cyclopentadienyl ligand in the product. And also the Cp weren't balanced (4 in but 2*2+2=6 out) and even Nb wasn't (1 in but 2 out). Here is a naively balanced form (shorthanded to clarify):

2(Cp)₄Nb + 4 HCl + 0.5 O₂ → [{Cp₂NbCl}₂O]Cl₂ + 4 CpH

User:Smokefoot might know better whether this is chemically correct in the context, or if other reagents are involved. I usually see "1/2" (or as a composed fraction) rather than "0.5" in this sort of context, but again might just be different authors' preferences. DMacks (talk) 16:05, 13 May 2024 (UTC)

Seems to be correct. Did you check it with literature source?T.vanschaik (talk) 16:42, 13 May 2024 (UTC)

OK, I put in a refined set of equations, here they are with comments.

Install Cp's on Nb, reduce Nb(V) to Nb(IV)

NbCl₅ + 5 NaC₅H₅ → 5 NaCl + (C₅H₅)₄Nb + "C₅H₅"

Protonolysis of 2 Cp's per Nb, oxidize Nb(IV) back to Nb(V)

2 (C₅H₅)₄Nb + 4 HCl + 0.5 O₂ → [(C₅H₅)₂NbCl]₂OCl₂ + 4 C₅H₆

Protonolysis of oxo (which stabilizes Nb(V)), re-reduce Nb(V) to Nb(IV). This eq is not balanced

[(C₅H₅)₂NbCl]₂OCl₂ + SnCl₂ + 2 HCl → 2 (C₅H₅)₂NbCl₂ + SnCl₄ + H₂O

The Inorganic Synthesis, which I have in front of me, is a little different and says that "The ionic substances containing niobium(V) that exist in these red solutions (referring to [(C₅H₅)₂NbCl]₂OCl₂) have not all been identified. ..."

BTW, I use two spaces between reagents and between reagents and arrows in equations, but some editors don't like that style. You folks are welcome to revise or whatever.--Smokefoot (talk) 16:52, 13 May 2024 (UTC)

Wiki source-code (like HTML) isn't sensitive to how much whitespace, just "any vs none". And our MOS does prescribe using spaces between coefficients and formulas and from other symbols. DMacks (talk) 18:11, 13 May 2024 (UTC)