# Have the STRUCTURES of synthesized anthropomorphic molecules (nanoputians) been verified experimentally?

Have the molecular structures of any synthesized anthropomorphic molecules (nanoputians) been verified experimentally?

This is a different question than this question as I am asking here about the structure, not the actual shape of the molecule. The importance of the distinction was pointed out in this helpful comment. Was there some property that was measured that confirmed that the correct, desired molecular structure had been in fact correctly synthesized?

• What would be satisfactory evidence to you? Surely they were characterized by the common spectroscopic techniques. Apr 16 '17 at 2:47
• I don't currently have access to the original article, but when I looked while reading your previous question, they seemed to have done some NMR analysis of various nanoputians. Apr 16 '17 at 2:51
• @Tyberius I don't have a copy of the paper right now either. If NMR can confirm or at least pretty-much confirm the final structure, that would be the basis of an excellent answer here. I'm assuming molecular weight alone would not be.
– uhoh
Apr 16 '17 at 2:55
• @jerepierre I'll defer to the authors, or to the SE community here on that. I don't have the paper now, so I can't see what they've done. And stop calling me Shirley :)
– uhoh
Apr 16 '17 at 2:59
• To publish a paper in the first place, you need lots of "proof" of the structure. You can't publish a paper saying "I think I made this" without NMR, MS, IR, elemental analysis, ... to back it up. Regarding your assumption that MW alone is not proof, it is true that NMR is slightly better, but it is still not 100% validation. They can be misinterpreted and there have been many cases in history of "I think I made this; here's the evidence" and then realising that they actually made something different that has qualitatively the same NMR spectrum. So, even NMR is not foolproof. Apr 16 '17 at 6:30

The first article wikipedia's entry refers to (here) is not only a publication behind a paywall, but with freely available supporting information, too. This in principle allows to replicate the work.

Browsing through the latter provides all / most / many details of how building blocks were prepared, how they were joined; including both numerical and graphical display of 1H and (broadband decoupled) 13C NMR spectral data. Like the following, found on page 22 of the SI:

and 13C NMR (same page, below)

Perhaps (i.e. the following is a speculation) the "main" article in the journal includes additional spectroscopic data (UV, IR; MS) or characterisation (melting point, combustion analysis, etc.) as the article stretches from page 8750 to 8766.

To have a more rounded perception of this work done, it would be interesting to look at the echo by others in the community. Which was the context this publication was cited? Did the original researchers continue to work on these compounds, and which context? In which ways other researchers than the authors echoed this work? Because ACS's page indicates the publication was noticed in freely accessible media, it were worth to look up about this article in SciFinder, too.

• I never thought to look for supporting information. Ok we're definitely on the right track!
– uhoh
Apr 16 '17 at 12:29
• I don't know if this type of analysis can confirm complete molecules, or if a mixture of incomplete molecules and/or broken molecules can produce similar spectra at this resolution.
– uhoh
Apr 16 '17 at 12:49
• @uhoh For some moment, I offer you an exchange here: chat.stackexchange.com/rooms/57191/nanoputains Apr 16 '17 at 12:54

I will probably edit this to add more as requested, but I have access to the original article.

As an example of how they characterized these molecules, here is the data they present for the "NanoChef":

Mp: 117-124 °C. IR (KBr): 2966, 2929, 2900, 2867, 2225, 1580, 1481, 1350, 1230, 1022 cm-1. 1H NMR (400 MHz, CDCl3): δ 7.63 (s, 1 H), 7.60 (s, 1 H), 7.47 (d, J ) 1.5 Hz, 2 H), 7.40 (t, J ) 1.5 Hz, 1 H), 7.22 (s, 1 H), 6.89 (m, 4 H), 2.39 (t, J ) 7.0 Hz, 4 H), 1.62 (sext, J ) 7.2 Hz, 4 H), 1.35 (s, 9 H), 1.29 (s, 9 H), 1.05 (t, J ) 7.2 Hz, 6 H). 13C NMR (100 MHz, CDCl3): δ 147.6, 136.2, 135.7, 134.4, 133.6, 129.8, 126.8, 125.9, 124.6, 123.3, 122.2, 121.7, 108.6, 108.0, 106.0, 104.9, 92.7, 91.4, 88.1, 79.4, 75.0, 30.9, 30.7, 28.3, 22.1, 21.3, 13.5. HRMS: calcd for C43H42O2 590.3185, found 590.3178.

So it appears they looked at melting point, IR, $\ce{H}$ NMR, and $\ce{^13C}$ NMR, as well as determining High Resolution Mass Spectrometry.

• Thanks! I've just got a copy yesterday as well, but since it's the first synthesis paper I've ever tried to sit and read, any help is greatly appreciated.
– uhoh
Apr 20 '17 at 1:22