Talk:Titanocene dichloride

Undue weight to anticancer work?
ChemAbs lists >3400 references to titanocene dichloride, and today, we get a listing primary references to one group who work on one declining aspect of this compound. WP:UNDUE. Seems parochial, and tacky. --Smokefoot (talk) 15:24, 4 February 2012 (UTC)


 * This diff shows the changes that Smokefoot made 18 minutes after posting the above, with the edit summary "trim multiple primary citations to one group on a non-application, cite just one for leading references, WP:UNDUE", and I'd like to make some comments.
 * 1. The alleged "non-application" has been in the article for at least 5 years.
 * 2. The alleged "non-application" is supported by the following citation, a SECONDARY source that I added to the article while expanding the coverage of titanocene dichloride's antitumour properties.
 * 3. Another source that I had yet to add is the book "Metals in Medicine" by Dabrowiak in 2009 which has a section on "Titanium compounds for treating cancer" (pages 167 to 177), which focuses primarily on titanocene dichloride and budotitane. It includes mention of the host-guest chemistry using CB[7] and molybdocene dichloride, FYI.
 * 4. Smokefoot's "trim" removed all mention of molybdocene dichloride, but left a reference to it behind. The statement on transferrin has been supported by a primary source for years, which Smokefoot removed.  The refences now after that comment don't support it.  This "trim" was done with a lack of care or competence, IMO, which is suprising and disappointing coming from Smokefoot.
 * 5. Secondary sources link the metallocene dihalides together, and whilst I appreciate the point that secondary sources are preferred to primary, I find that the primary sources provide detail that the secondary ones lack. Maybe I went too far using primary sources - as my talk page notes, I'm not at my best right now - and I certainly have used the Metals in Medicine book, but I suggest a discussion without a wholesale reversion might have been more productive, and I didn't need to be called "parochial" and "tacky" in an edit summary nor accused of ulterior motives in editing on my talk page.
 * 6. I would favour retitling the section something like "Antitumour properties" because the clinical trials did not lead to actual medical use. I should have done this on the molybdocene dichloride article, and will later on.  I will revert Smokefoot's "trim" and take another stab at the section including adding the other secondary source and looking again at what primary material to use.  Perhaps we can then have a polite and productive discussion?
 * EdChem (talk) 13:15, 5 February 2012 (UTC)
 * Well first of all, our condolences at an apparently difficult time for you. I should have noticed. So we might wait for you to recollect before we engage on this and related articles, since there are more important things in life than Wikipedia.  Briefly, I am very vigilant to even inadvertent conflicts of interest or undue weight on themes where I am expert, but we can deal with all this later when you have come to some personal resolution.  With best wishes, --Smokefoot (talk) 14:38, 5 February 2012 (UTC)
 * Well first of all, our condolences at an apparently difficult time for you. I should have noticed. So we might wait for you to recollect before we engage on this and related articles, since there are more important things in life than Wikipedia.  Briefly, I am very vigilant to even inadvertent conflicts of interest or undue weight on themes where I am expert, but we can deal with all this later when you have come to some personal resolution.  With best wishes, --Smokefoot (talk) 14:38, 5 February 2012 (UTC)

"Huh"
Hi, I noticed your comment in this diff relating to the following text:
 * Viewing the Cp ligands as tridentate, the complex has a coordination number of 8.

If you consider a Cp&minus; ligand as having two discrete carbon-carbon double bonds and the negative charge localised on the rings' fifth carbon atom, then it can bind to a metal occupying three of the metal centre's coordinate sites: two &eta;2-olefin bonds to &pi;-systems and a &sigma;-bond using the lone pair. This is, I think, what is meant. EdChem (talk) 15:25, 19 June 2017 (UTC)
 * Do you have any reason why it shouldn't be removed? OrganoMetallurgy (talk) 16:10, 19 June 2017 (UTC)
 * Sure, it can donate three electron pairs, which is important for electron counting (bonding, electron configuration, the 18-electron rule, etc.). but that's not what coordination number is. Without evidence to the contrary, Cp binds its five atoms, which is instead what is relevant for coordination number. And the whole concept of denticity is for non-consecutive atoms whereas here we have hapticity. The structural details of "all five atoms" and "hapacity" are verified by the "η5-" nomenclature detail. DMacks (talk) 18:33, 19 June 2017 (UTC)
 * the idea that Cp is tridentate-"like" is a memory or teaching device. In that way, ferrocene is seen as a ML4X2 octahedral.  This terminology, which maybe I inserted, would confuse many readers, and like DMacks says, denies delocalization.  In the old, old days, there was the tought that eta-6-C6H6 was localized upon coordination (bad crystallography), and of course folks loved the idea that benzene is a frozen triene.  etc.  --Smokefoot (talk) 19:46, 19 June 2017 (UTC)
 * No worries, glad it's all sorted. I've used this and related compounds, but it's been a while since I studied their electronic details and didn't know if there was any special detail or recent research I was overlooking. DMacks (talk) 03:03, 20 June 2017 (UTC)

I agree with OrganoMetallurgy's perspective, it doesn't belong here. Possibly include it in an article on coordination number as an approach for reconciling why metals with typically six coordination sites might suddenly appear to have ten, but appreciating bonding like this is more through electron counting and MOs, etc. EdChem (talk) 06:22, 20 June 2017 (UTC)

Incorrect Citation
I noticed that citation 20 does not include the reactions shown. I'm looking for the right citation now because I need it for my work, I'll update if I find it. 76.176.147.6 (talk) 20:36, 1 September 2020 (UTC)
 * Do you read English? "bis(η5‐2,4‐cyclopentadienyl)bis(trimethylphosphine)titanium is prepared by the reduction of Cp2TiCl2 by magnesium in the presence of trimethylphosphine"--Smokefoot (talk) 21:23, 1 September 2020 (UTC)