A series of 2,6-dibenzhydryl-N-(2-phenyliminoacenaphthylenylidene)-4-methylbenzenamines ( L1 - L5 ) and the nickel(II) dibromide complexes thereof ( C1 - C5 ) were synthesized and fully characterized. The molecular structures of representative complexes were determined by single-crystal X-ray diffraction and revealed a distorted-pyramidal geometry at nickel. All nickel(II) procatalysts exhibited very high activity for the polymerization of ethylene, with activities as high as the range of 107 g of PE (mol of Ni)-1 h-1

Ethylene polymerization was performed using a series of 2-[1-(2,6-dibenzhydrylphenylimino)ethyl]-6-[1-(arylimino)ethyl]pyridyliron(II) chlorides with the activity in the range of 10(7) g PE mol(-1) (Fe) h(-1), which is the highest observed in iron procatalysts at elevated reaction temperatures such as 80 °C in the presence of MMAO and 60 °C in the presence of MAO, without any trace of ethylene oligomerization.

We propose a novel physical mechanism for breaking the diffraction barrier in the far field. Termed fluorescence emission difference microscopy (FED), our approach is based on the intensity difference between two differently acquired images. When fluorescence saturation is applied, the resolving ability of FED can be further enhanced. A detailed theoretical analysis and a series of simulation tests are performed. The validity of FED in practical use is demonstrated by experiments on fluorescent nanoparticles and biological cells in which a spatial resolution of <λ/4 is achieved. Featuring the potential to realize a high imaging speed, this approach may be widely applied in nanoscale investigations.