Running the green light….

Antony Williams, who I had a great time with over coffee yesterday, alerted me to his blog post about a new chemical with some amazing properties – shining UV light onto the solution turns the liquid green instantaneously, and removal of the UV source results in instant change of color from green back to transparent.
Aaron Rowe and Kyle Finchsigmate also blogged about it.
You can see the chemical structure here:
See those two rings with nitrogens highlighted in blue? See the bond that connects those two rings? That bond is broken by UV light and immediately rebinds once the light is gone.
Think of the applications for this!
And here is a video so you can observe the color changes for yourself:

4 responses to “Running the green light….

  1. I got a deal on a bunch of UV LED’s. So I hooked up three of them to my 5V power supply and then passed various items nearby. I found the strip embedded in all U.S. currency with the denomination that glows either green or blue under UV light.
    Then I found out my drivers license has the RI Anchor and motto “Hope” that stand out when UV light is applied.
    Then there’s the Bud Light t-shirt. It glows when exposed to UV light.

  2. Hank Roberts

    Lots of things fluoresce green.
    This chemical, they say, turns green — that is it absorbs everything but green light and so looks that color in white light.

  3. Hank,
    The bond break described in the post probably just emits energy in the form of light with a wavelength that corresponds to the color green.

  4. From what I’ve understood of the article, the bond is the least energetic state, and with that bond it’s transparent. When energy is fed in, the bond can break, reshaping the molecule into one which is opaque and reflects green light.
    I can see some applications for things like this, such as glasses that get darker in sunlight.