Talk:Hapticity

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Contents 1 Hapto - where does it come from? 2 What has Zeise got to do with this? 3 Two questions 4 Proposal

[edit] Hapto - where does it come from?

I removed this sentence here: [1] -- "eta is the first letter of the Greek word pronounced "hapto", meaning "held" in Greek". According to some Wikipedians on the language reference desk, this isn't the case. Does IUPAC have anything interesting about the history of this symbol? --HappyCamper 18:55, 23 July 2006 (UTC)

Delighted to see interest in this article, even if the focus is off the chemistry. Here's the source: "Proposed nomenclature for olefin-metal and other organometallic complexes" F. Albert Cotton J. Am. Chem. Soc.; 1968; 90(22); 6230-6232. Here is the key except: "The adjectival prefix hapto (from the Greek haptein, ηαπτειν, to fasten, denoting contact or combination^2a) is placed before the name of the olefin." {I think that I transcribed the Gk correctly from the PDF journal article}

"(2a) “Webster’s Third New International Dictionary,” unabridged, 1961, G. and C. Merriam Co., Springfield, Mass."

So I will reinsert a modification of this information into the article. Thank you for the suggestion and keep checking up - WE needs that!--Smokefoot 20:11, 23 July 2006 (UTC)

Ah :-) Is this the same person who wrote the little book on group theory and chemistry? --HappyCamper 21:25, 23 July 2006 (UTC)

ηαπτειν isn't a word though...eta is not an H, the H in English comes from the alpha pronounced with an h-like sound in front of it, which is not marked by any letter but by a "breathing mark". Adam Bishop 21:37, 23 July 2006 (UTC)

Then, what is Cotton referring to in his original paper? Hm...I should get a hold of a copy to see more closely what is happening. I don't know Greek, so if I sound silly, my apologies in advance. I will ask a classics colleague about this, and if I find anything interesting, I'll let everyone know. --HappyCamper 21:44, 23 July 2006 (UTC)

Apparently hapto is derived from the same root as used for hapten in biology and apparently it is supposed to mean 'fasten" more than "hold" which I used in an early draft of this article. Organometallic chemists sound out the "h" in hapto. Very possibly imperfect from the perspective of classics professor, but this nomenclature is pervasive and indelible. --Smokefoot 22:22, 23 July 2006 (UTC)

I assume Cotton just transliterated "haptein" and assumed the H was an eta, or it's just a typo. It's pronounced "hapto-" in Greek too, they just don't have a H in the spelling. Adam Bishop 00:25, 24 July 2006 (UTC)

Thanks for the clarification. It's really helpful! --HappyCamper 05:02, 24 July 2006 (UTC)

[edit] What has Zeise got to do with this?

1) I recommend relocating the fascinating bits on Zeise's salt and the associated personalities possibly to the history of organometallic chemistry or history of Zeise's salt. The hapto thing directly comes from organometallics as practiced in the 60's with polyolefins that gave really complicated molecules. Novices might say, η²-alkene, and this terminology is formally valid, but this is also quite obvious because virtually no other bonding modes are known for alkenes. 2) "The term was introduced in organometallic nomenclature in during the mid-1950s" Hapticity for organometallic chem was introduced by Cotton in the 60's, I thought we settled this. 3) We might revise the subtitle on molecules with "hapticity" molecules dont have hapticity any more than they have "stereochemistry". Ligands do.--Smokefoot 01:04, 25 July 2006 (UTC)

The business on Zeise's salt and Dunitz X-ray structure seems like a giant non sequitur. Yes, these are facts - but pertinent or cruft?--Smokefoot 04:52, 26 July 2006 (UTC)

Well, I like that sort of information, but you're right, in a sense, it's a bit too esoteric for what is needed here. We need something like History of Hapticity to place all these things perhaps. Not sure what to do really. --HappyCamper 21:24, 26 September 2006 (UTC)

[edit] Two questions

1. Can a reaction be degenerate? Check out the degenerate page.
2. I think "imaginary symmetry axis" is a little bit wrong, because the symmetry axis is definitely there, it's not imaginary. There is no axle, but I think there is an axis of symmetry. Thoughts??--Chris 20:45, 26 September 2006 (UTC)

I don't understand the first question. Could you rephrase it? As for the second one, well, it's semantics I think. There isn't a "stick" that the two sandwiches rotate around, but it's definitely there. Maybe we should change that to "rotating around the principle axis of symmetry". That would be more precise. --HappyCamper 21:22, 26 September 2006 (UTC)

For the first, I think what is meant is that it is a 'nonreaction reaction' .. hence, it does not generate a new species (but it does generate another species, one can prove that the metal is hopping to another carbon using nifty labeling experiments, e.g. via NMR). I am not good enough in the definition of degeneracy to see if it is indeed a proper term here. For the second, HappyCampers suggestion might be a good one. --Dirk Beetstra ^{T C} 21:43, 26 September 2006 (UTC)

I just meant that degeneracy applies to energy levels, not reactions.--Chris 06:21, 27 September 2006 (UTC)

I made this edit here [2], but turns out principal axis doesn't have a definition for what we are thinking of right now. What's a good one to use? The principle axis is the group element which has the highest symmetry, or something like that? --HappyCamper 00:13, 27 September 2006 (UTC)

I put a link to rotational symmetry, which has the definition you were looking for.--Chris 06:21, 27 September 2006 (UTC)

[edit] Proposal

I like the page but I think it could use a quick reference to a simlipifed deffinition of the term Hapticity. Somthing like "In most cases Hapticity is the number of times a ligand unit binds to the traget molecule". Lets face it most pepole who will come to this page will be students wanting a collage level difinition. Bsanchez 12:20, 9 August 2007 (UTC)

Well the spirit of WE-chem is that you could try out a simplified definition - even an imperfect one - and await the edits, but the one you suggest is incorrect. Then again, the term is routinely misused even by professional scientists, who confuse it with denticity. —The preceding unsigned comment was added by Smokefoot (talk • contribs) 03:13, 10 August 2007.

What you say its true, that pepole sould use denticity, however i'm currently at a good uni doing my thesis and every one uses the term hapticity. I'm going to mull it over for a few days to see if I can find a nice way of putting it.Bsanchez 07:31, 16 August 2007 (UTC)

Oh my! Folks at so-called "good uni's" are mortal: maybe you should edit their usage, not the article! Anyway, it's only nomenclature and not a deeply significant principle.--Smokefoot 12:50, 16 August 2007 (UTC)