semicarbazones, imines with aldehydes
Could any one please help me understand some thing, i have made cinnamaldehyde from benzaldehyde using the wittig reaction, and i used it again to extend the chain out, i added a semicarbazone to the moldecule, which removed the oxygen bond to nitrogen, why does it attck the oxygen? i was told this also makes it more flurecent, i am making a "spydust you see, a chemical to catch criminals in the act, i just dont understand what i have made"
why does this attack the o and why does it become more fluorescent, i understand that i have imines, but i again dont know why, i have now just added an amino acid to the solution and i am waiting for the reaction to happen, is there any thing you can help me with that may help me understand this alittle better, sorry x thank you for your time!!
Hi, i can answer part of ur question, the reaction betw semicarbazide and aldehyde(extended cinnemald). In semicarbazide, NH2-NH-C=o-NH2. I cud not put keto oxygen in down position, but imagine in that way. Now, only hydrogen attached to Nitrogen is weakly bonded and ready to loose, as Nitrogen has lonepair of electrons and highly electron dense, so it can lose Hydrogen electrons (which is electropositive) to undergo conjugation with carbonyl carbon,which gives it more stability. In the aldehyde structure of cinnemald, the HC=O has electron negativity oxygen atom which is also bulky. Thus the electropositive hydrogens prefer electronegative oxygen and always =o is ustable, due to bulky nature of oxygen and weak double bond character. So =O easily breaks and forms -OH and takes away the other hydrogen from nitrogen, thereby forming water molc.
Hope this helps. But you have a nice thought provoking question there. Let me know if you find the answer for flouresence.