Synthesis And Property Study Of Ru Olefin Metathesis Catalyst

Olefin metathesis reactions refer to the process that carbon-carbon double bonds were recombined to form new molecules which catalysted by metal complexes.In general,there are two factors that affect the central nature of the ruthenium metal: one is the introduction of a large volume of N-heterocyclic carbene(NHC)ligand;another is the chelating atomic species and the chelating atoms of the space and electronic effects.In addition,ruthenium residues are produced during the catalytic reaction,and in order to reduce the ruthenium residue in the product and to improve the e fficiency of the catalyst,on the basis of previous research work,in this paper,several new ruthenium catalysts have been designed and synthesized,and their properties have been studied.1.A series of nitrogen-containing chelated ruthenium carbene metathesis catalysts were synthesized.In order to improve the catalytic activity and initiation rate of the nitrogen chelate ruthenium carbene catalyst,we introduce the electron withdrawing group into the imine carbon and the benzylidene benzene so that the chelated nitrogen atoms can be quickly dissociated from the metal center,The catalytic activity and initiation rate of the catalyst containing the strong electron-withdrawing group is same to that of the Hoveyda catalyst.At the same time,the series of catalysts have catalytic activity for the ring-closing metathesis(RCM)reaction of N-protected and O-protected substrates and the cross-metathesis(CM)reaction of allyl benzoate and styrene.2.A multi-core ruthenium olefin metathesis catalyst has been synthesized.In the synthesis of the catalyst,the initial inference shows that a multi-core catalyst was obtained accidentally.The catalyst has high catalytic activity and selectivity in the presence of N-protected or O-protected substrates,and it is also activitied for the cross metathesis reaction(CM).3.An indolinooxazolidine tagged N-heterocyclic carbene Ru olefin metathesis catalyst was synthesized.This complex is a homogeneous catalyst and has high catalytic activity in the presence of N-protected or O-protected substrates.Importantly,under acidic condition the indolinooxazolidine tag exists as an open protonated form and under basic condition the tag is in a closed form.The distribution of this catalyst in a two-phase system can be controlled b y simply changing the pH,making the recovery of this catalyst easily obtainable.4.A ruthenium carbene complex containing pyrrole nitrogen heterocyclic ligands was synthesized.The preparation method of complex was simple and the product to obtain,easily.Since the complex structure contains two pyrrole nitrogen heterocyclic ligands,it has good thermal stability,and even it can be placed for a long time without deterioration in the solution.