金属-有机骨架材料(MOF)的分类及其在计算化学的发展和前景李鹏李芳2020/2/1ContentA.常见的金属-有机骨架材料分类及其特点B.MOF材料的计算化学研究方法及应用C.MOF材料应用的前景A.常见的金属-有机骨架材料分类a.IRMOF系列材料(IsoreticularMetal-OrganicFramework)b.ZIF系列材料(Zeoliticimidazolateframework)c.CPL系列材料(CoordinationPillared-Layer)d.MIL系列材料(MaterialsofInstitutLavoisier)e.PCN系列材料(PorousCoordinationNetwork)f.UiO系列材料(UniversityofOslo)通过使用含更长的二羧酸配体反应物,IRMOF系列化合物的孔道尺寸可以增大到28.8Å,孔隙率从55.8%增大到91.1%,大大超过了沸石的孔隙率。IRMOF材料用于合成IRMOF系列材料的不同配体IRMOF是由分离的次级结构单元[Zn4O]6+无机基团与一系列芳香羧酸配体,以八面体形式桥连自组装而成的微孔晶体材料。MohamedEddaoudi,JaheonKim,NathanielRosi,DavidVodak,JosephWachter,MichaelO’Keeffe,OmarM.Yaghi*.SystematicDesignofPoreSizeandFunctionalityinIsoreticularMOFsandTheirApplicationinMethaneStorage.Science,2003,300,1127ZIF材料ZIF,即类沸石咪唑酯骨架材料,是利用Zn(Ⅱ)或Co(Ⅱ)与咪唑配体反应,合成出的类沸石结构的MOF材料。BoWang,AdrienP.Coˆte´,HiroyasuFurukawa,MichaelO’Keeffe&OmarM.Yaghi.Nature,2008,(453)207.ANHPHAN,CHRISTIANJ.DOONAN,FERNANDOJ.URIBE-ROMO,CAROLYNB.KNOBLER,MICHAELO’KEEFFE,ANDOMARM.YAGHI*.ACCOUNTSOFCHEMICALRESEARCH.2010(43).58-67.CPL系列材料CPL材料的结构由六配位金属元素与中性的含氮杂环类的2,2’-联吡啶、4,4’-联吡啶、苯酚等配体配位而成。其中的四个配位位置是金属和吡嗪类羧酸配体链接而成的二维平面结构,剩下的两个位置是金属与线形二齿有机配体配位形成。Angew.Chem.Int.Ed.1999,38,No.1-2,140-143Angew.Chem.Int.Ed.2008,120,3978–3982MIL系列材料MIL材料是使用不同的过渡金属元素和琥珀酸、戊二酸等二羧酸配体合成。其最大的一个特点就是在外界因素的刺激下,材料结构会在大孔和窄孔两种形态之间转变,即呼吸现象。PCN材料PCN系列材料含有多个立方八面体纳米孔笼,并在空间上形成孔笼-孔道状拓扑结构。这种材料在气体存储方面有巨大潜力。J.AM.CHEM.SOC.2008,130,1012-1016UiO系列材料UiO材料由含Zr(锆)的正八面体[Zr6O4(OH)4]与12个对苯二甲酸(BDC)有机配体相连,形成包含八面体中心孔笼和八个四面体角笼的三维微孔结构。J.AM.CHEM.SOC.2008,130,13850–13851Chem.Commun.,2011,47,9603–9605B.MOF材料的计算化学研究方法及应用量子力学方法分子模拟方法分子力学方法第一性原理方法、密度泛函理论蒙特卡罗方法、分子动力学方法Experimental−ComputationalcombinationThemethanemoleculeusingtheTransferablePotentialsforPhaseEquilibriaUnitedAtom(TraPPE-UA)forcefield,inwhichCH4ismodeledasasingle,unchargedLJspherelocatedonthecarbonatom.FortheZIFatoms,weuseLJparameterstakenfromtheOptimizedPotentialsforLiquidSimulationsAllAtom(OPLS-AA)forcefield,UFFforZn.GCMC→ComplexChemicalSystems(MCCCS)Towheeprogram.Bindingenergies→Large-scaleAtomic/MolecularMassivelyParallelSimulator(LAMMPS)J.Phys.Chem.C2013,117,10326−10335ThecorrespondingisothermsfromtheGCMCsimulation,whichagreewithexperimentallymeasuredvaluestowithin13%,validatingourchosenOPLSparametersforthesesystems.TheCH4adsorptions:ZIF-71-97-93-96-25.TheseresultssuggestthatthedominantinfluenceonadsorptionofCH4intheZIFsisBETsurfaceareaorfreevolume,consistentwithresultsobtainedbytheSnurrgroupandWangetal.低压高压RSCAdv.,2014,4,16503GCMCsimulationmethodsProgram:MultipurposeSimulationCode(MuSiC-4.0)developedbytheSnurrgroup.Interconversionoffugacityandpressure:Peng–Robinsonequationofstate(PREOS).Model:ZIF-8frameworksweretreatedasrigidwithfrozenatom,H2andCH4wererepresentedbyaunited–atommodel,N2andCO2weremimickedasathree-siterigidmodel.CutoffradiusofLJinteractions:1.4nmLong-rangeelectrostaticinteractions:EwaldmethodSteps:107,50%forequilibration,50%forcalculatingtheensembleaverages.Forcefieldparameters:Ԑ=0.635ԐUFFandσ=1.0σUFFForcefieldvalidationTheeffectofstructureontheexcessCH4uptakefollowstheorderZIF8HLZIF-8ZIF8_55CH4UCZIF8_ja3AdsorptionsitesAt1barand77K,alittleamountofH2moleculesareadsorbedonZIF-8frameworkandtheirpreferentialadsorptionsitesareclosetotheimidazolerings.Withincreasingofgaspressure,moreH2moleculesareadsorbedinthemiddleofthefacesoftheaccessiblesurfaceareaofZIF-8framework.TheCH4adsorptionisothermsforfourdifferentinitialstructuresofZIF-8at298KhavebeencomputedusingGCMCsimulationswiththeproposedforcefieldadsorptionisothermsforfourgasessuchasCH4,H2,CO2andN2atdifferenttemperatureswerecomputedusingGCMCsimulationandwerefoundtobeinagoodagreementwiththeexperimentaldata.InthecaseofH2,theprobabilitydensitydistributionprofilesindicatethatthepreferentialadsorptionsitesofH2moleculesinZIF-8arelocatedclosetotheMeIMringswherethehost–guestVDWinteractionsaremaximal,asrevealedbythepotentialenergysurfaces(PES).ConclusionsMOF材料模拟的前景在氢储领域的应用在气体吸附与分离领域的应用在催化反应中的应用在药物缓释方面的应用