CRYSTAL-STRUCTURE AND HYDROGEN-BONDING CHARACTERISTICS OF N,N-BIS(3,5-DIMETHYL-2-HYDROXYBENZYL)METHYLAMINE, A BENZOXAZINE DIMER

The X-ray crystal structure of N,N-bis(3,5-dimethyl-2-hydroxybenzyl) m ethylamine as a model dimer for benzoxazine-based phenolic resins is p resented, and a hydrogen-bonding scheme involving both inter- and intr amolecular hydrogen bonding is proposed. Hydrogen bonding of this mode l dimer is further studied with Fourier transform infrared (FT-IR) spe ctroscopy in crystalline, quenched, and molten phases as well as in so lution, Additional hydrogen-bonding schemes are proposed. These result s are compared to results obtained from molecular modeling using a mod el dimer with a tert-butyl functionality. The preferred conformations of methyl functional trimers are modeled based on preferred dimer conf ormations.