A series of chiral and achiral bis(2-oxazolinylphenolato)nickel(II) complexes 2 were synthesized by reactions of various 2-(4,5-dihydro-2-oxazolyl)phenol derivatives with nickel chloride hexahydrate. The molecular structure of complex 2a was determined by X-ray single crystal diffraction. The crystal of complex 2a was monoclinic, space group P21 with cell dimension of a=1.1121(4) nm, b=0.9472(3) nm, c=1.4113(5) nm, ==90, =91.450(6), V=1.4861(8) nm3, Z=2, and =0.693 mm—1. In the solid state, the nickel(II) ion was in a square-planar coordination geometry. The catalytic activities of complexes 2 in Baeyer-Villiger reaction with molecular oxygen were investigated.
Two new complexes [η^5-C5H4CMe2-（p-fluorophenyl）]TiCL3 （1） and [η^5-C4h4C（cyclo-C5H10）-（p-fluorophenyl）]TiCl3 （2） were synthesized and characterized. Their activities and selectivities for trimerization of ethylene were investigated. The introduction of fluorine atom greatly weakened the arene coordination, but this disadvantageous factor can be eliminated by introduction of a bulky substituent, such as cyclo-C5H10, to the bridging carbon linked to the Cp ring. The combinative effect of the fluorine substitute and the bridging unit can make complex 2 as a highly active and selective catalyst for ethylene trimerization. Its productivity and selectivity for 1-hexene can reach 1024.0 kg·mol^-1·h^-1 and 99.3% respectively.
