Mar
14

Creases and Precipitates

First of all, good news.  With some of the new dianhydride I have synthesized, I have been able to make creasable polymers, which means they are high molecular weight.  I will soon proceed to attempt a bulk polymer synthesis. I have also been stuck on the new dianhydride syntheses for a while.  I did some molecular modelling, and it turns out the that lowest energy state for the singly substituted ETBDA-TC is contorted in such a way as to prevent a second addition, and this is why I was seeing residual bisphenol signatures, so I have mostly scrapped that compound.  The TBD dianhydride was proceeding well until the isolation of the dianhydride.  Unfortunately, in many solvents like Ac2O and EtOAc, a saturated solution forms a sludge rather than precipitating when cooled.  This binds the solvent in a matrix and makes it difficult to isolate.  After thoroughly drying it and experimenting with different solvents, I have been able to extract small amounts with hexanes, in which it is only slightly soluble.  The NMR and  IR look good for this compound, so I will take a meltemp and elemental analysis.  I am really hoping to form a crystal by some means for XRD, so I am trying a variety of methods, but so far no luck.  That is about it.  I am wrapping up my work and looking at a few more polymers while  I write my thesis, so hopefully all goes well in the next month or so.