Abstract: “Nitroxyl (HNO) is the one-electron reduced form of nitric oxide, a compound whose high reactivity makes it difficult to study. Previously, we developed NitroxylFluor, a fluorescent probe suitable for live-cell fluorescence imaging of HNO. This project aims to create derivatives of NitroxylFluor to optimize its localization, spectral properties, and photophysical properties. The proposed three congeners will be red-shifted as we replace the endocyclic oxygen of the xanthene chromophore with a quaternary carbon, dimethylsilicon, and a sulfonyl group. These probes will allow for multiplexed imaging with other probes, fluorescent proteins, or other labels to see interaction between HNO and other analytes and targets. With longer wavelength emissions from these derivatives, there will be reduced light scattering allowing deeper tissue penetration for in vivo imaging. With organelle directing groups, these probes will also give us a greater understanding of where HNO is produced at the subcellular level.”
East Central IL ACS Undergraduate Research Conference
Thank you for joining us for the 5th Annual ECI-ACS conference!
This a very beautiful work. I was wondering, is there a desired fluorescence color for the third compound when the chemical structures are proposed?
Can blue-shifted derivatives be attempted with NitroxylFluor?
If so, how will the strategy differ if attempting a blue-shift instead of a red-shift?
I am thinking, after Magenta and Yellow, your team only need Cyan to complete the primary colors. Of course, you will lose the pros of working with longer wavelengths, but let’s keep that fact aside.
Also, out of all the future work plans, which one would you like to try first?
Thank you, Vianney!
The NitroxylFluor derivative with the sulfonyl group will have absorption and emission in the near-IR region.
In the original NitroxylFluor project, the lab developed the NitroxylBlue series with absorption around 350nm and emission around 448nm. NitroxylFluor was created after the NitroxylBlue probes because the lab wanted probes with absorption and emissions in the visible light region.
Right now, I’m working on synthesizing the chlorinated Magenta dye.
Thank you for the questions!
Thank you for the response. Even if you do not have time in your presentation for a full analysis of the NMR spectra (and given the amount of synthetic work you have done, I believe you may not have time for full analysis) at least state it as you did here how the compounds were characterized. Nice job.
Thank you for the feedback!
I liked the use of multiple posters to allow the viewer to see the details of your presentation. A couple of questions:
1) what are the yields of your intermediate steps and the overall yield of the yellow product that you synthesized
2) How do you know you have your intermediate and final products? What method(s) did you use to determine the intermediate and final products? (UV VIS, NMR, Mass Spec, elemental analysis). That evidence would be helpful in the presentation to lend validity to your claims of synthetic product.
Thank you for your questions and feedback!
1) The yield of each intermediate and the final product are listed below.
Negishi coupling – 99%
Grignard – 88%
Ring closure with boron tribromide – 80%
DDQ oxidation – 99%
I was unable to obtain a clean product from the chlorination step so I ran the TBS protection on a mixture and got a yield of 12% over the two steps.
Lithiation to the dye – 54%
EDC coupling – 54%
Trityl deprotection to the final product – 88%
2) I used proton NMR to determine the intermediates and the final product. Thank you for the advice. I will be sure to include this information in the future.