Tri-block amphiphilic copolymers with hybrid architectures were synthesized by coupling linear （poly（ethylene） glycol）（PEG） and dendritic second-generation Fréchet-type poly（benzyl ether）（PBE） via the Williamson reaction （Gisotv,et al. Angew Chem,Int Ed Engl,1992,31:1200～1202）.Our experimental study shows that the powerful two-dimensional （）1H- （）13C heteronuclear multiple-quantum correlation （HMQC） and two-dimensional （）1H- （）13C heteronuclear multiple-bond correlation （HMBC） NMR techniques rather than the classical one-dimensional （）1H and （）13C-NMR methods can provide clear evidence to verify the formation of the tri-block copolymers.In our measurements HMQC and HMBC NMR techniques directly detected the signal of ether bonds bridged in-between PBE dendrons and PEG blocks,therefore,the formation of the block copolymers are evidently confirmed in molecular level.This work also provides a general method to exactly confirm the formation of block copolymers.
A new ligand N,N′-bis(2-methelene-1,10-phenanthroline)-3,6-dioxa-1,8-octaneethylenediamine(L) and the corresponding complexes LaL, LaL(Phe), and LaL( Try) were synthesized. The interaction of the complexes with calf thymus DNA was studied by means of electronic absorbance spectra, flurescence spectra, circula r dichroic spectra and viscosity experiments. All the results indicate that the complexes may interact mainly with calf thymus DNA by intercalation and coordina tion binding.
