Synthesis Of Lewis Base-Accessible MOFs And Their Catalysis To Cycloaddition Of CO₂ With Epoxides

Recently,metal-organic frameworks（MOFs）have been extensively applied in catalysis.As a new series of microporous materials,the structural topology,BET surface and pore of MOFs can be easily modified,and diverse Lewis acid/base active sites can be introduced into the framework.So,the fictionalization of MOFs can achieve the effective catalysis of versatile organic reactions.In this work,through different crystallographic methods,three new metal-orgnaic frameworks with Lewis base sites have been synthesized,and their catalysis to the cycloaddition of CO₂ with epoxides has been studied in detail.1、Synthesis of amino-modified microporous entangled MOF and its catalysisA new MOF,[Zn（2-NH₂-bpca）（bimb）]·xsolvents（1）has been constructed based on 2-amino-biphenyl-4,4’-dicarboxylic acid（2-NH₂-H₂bpdc）.This compound exhibits five-fold interpenetration of dia net in the[3+2]entangled mode.Coordination-free amino groups direct into the channels as the Lewis base.It was found that Yield of1,2-epoxyheptane almost reached to 92.6%with catalyst 1（5%）and TBAB（5%）at 1atm CO₂ and 80°C for 12 h.The recycle catalytic experiments show that the yield of Yield still can reach to 84.5%after five runs,which indicates the excellent sustainability and practicability of 1.The substrates 1,2-epoxydecane,epichlorohydrin and styrene oxide can also be totally converted to related cyclic carbonates.2、Synthesis of amino-decorated self-penetrating MOF from high-connected SBU and its catalysisBased on a rigid ligand 3-amino-biphenyl-4,4’-dicarboxylic acid（3-NH₂-H₂bpdc）,a new MOF[Zn₄O（NH₂-bpdc）₃（bpe）_0.5（H₂O）]·10DMF（2）has been built through the mixed-ligand strategy.This compound exhibits a senven-connected self-penetrating framework,with abundant metal active sites and coordination-free amino moieties as the Lewis base.Catalysis results showed that Yield of 1,2-epoxyheptane almost reached to 94.2%with catalyst 2（5%）and TBAB（5%）at 1 atm CO₂ and 80°C for 12h.The recycle catalytic experiments show that the yield of Yield still can reach to86.4%after five runs,which indicates the excellent sustainability and practicability of2.The substrates 1,2-epoxydecane,epichlorohydrin and styrene oxide can also be converted to related cyclic carbonates over 99%.3、Synthesis of isoquinoline modulated microporous MOF and its catalysisBased on 5-（isoquinolin-5-yl）isophthalic acid,a new microporous MOF named[Cu₃（L）₃·2DMF]·2DMF（3）.This compound presents a unusual{3,4,6}-connected topology with cage-like pore and 1D channel.This compound exhibits a high iodine capture of 661.84 mg/g.Catalysis results showed that Yield of 1,2-epoxyheptane almost reached to 99%with catalyst 3（5%）and TBAB（5%）at 1 atm CO₂ and 80°C for 12 h.The recycle catalytic experiments show that the yield of Yield still can reach to 94.1%after five runs,which indicates the excellent sustainability and practicability of 3.The substrates 1,2-epoxydecane,epichlorohydrin and styrene oxide can also be converted to related cyclic carbonates with sanctified yields.