IR, NMR and structure of some prepared bismaleimides and DFT Study

Bismaleimides (BMIs) are versatile building blocks in polymer synthesis. BMIs thermosetting addition polyimide resins are the key components of aeroengines and aircraft because of their high temperature stability and fatigue resistance. BMI crosslinkers are commonly used to explore and characterize protein structure or interactions by site specific biomolecule modification (i.e. click chemistry), and forming crosslinks between sites in a protein oligomer or interaction can assist in determining intra - and intermolecular distances. In this study some bismaleimides required in gram quantities and economic synthesis of these compounds in our laboratory and on the other hand, detailed spectral for this class of compounds study. FT-IR spectra show the position of the absorption bands vary with the type and length of the link spacer (R) between the two maleimide rings on the studied bismaleimides. Spin-lattice relaxation times T1 for 1HNMR (1H TI) values of imide protons for model system of studied bismalimides appeared systematically correlated with the differences in type (direct, aromatic and aliphatic) and aliphatic chain length spacer link between two maleimides rings.