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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: collinsmith on April 21, 2011, 10:06:31 AM

Title: NMR IR and Mass SPec Graph Reading
Post by: collinsmith on April 21, 2011, 10:06:31 AM

I'm having problems trying to put together this unknown compound so here is what i have... using the the Mass spec i was able to find out the molecular formula (c6h16o1), and i have 1 peak with a multiplet meaning i have 1 equivalent Peak. but now from that one peak is really throwing me a curve ball!
. so here are the graphs... PLEASE HELP IM GOING CRAZY!!!!!!!!!!!

IR spec
http://img832.imageshack.us/i/img20110420212729.jpg/
NMR spec
http://img535.imageshack.us/i/img20110420223047.jpg/
Mass Spec
http://img156.imageshack.us/i/sgcshpunk2massspec.jpg/

Thanks in advance greatly appreciated

Title: Re: NMR IR and Mass SPec Graph Reading
Post by: MOTOBALL on April 23, 2011, 01:13:26 PM

1. Unfortunately your formula is wrong; C6H16O1N0 (element symbols are ALWAYS in caps) requires [6 + 1] + [0 - 16]/2 = -1 double bond equivalents, which is nonsensical.

2.  There are some issues with the mass spectrum.  If m/z 103-5 is the molecular ion cluster, then m/z 94 is not real (i.e. is background); if m/z 94 is real, then m/z 103-5 is background OR the spectrum is a composite of two compounds. Your prof. has either deliberately, or unknowingly, given you a curve-ball.

3.  I recognize the spectrum as probably due to a well-known molecule, MW 94 Da; ignore the m/z 103-5 cluster !!

Good Luck.