平面正方形配合物取代反应的机理和反位效应.pdf

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1、第24卷第4期化学研究中国科技核心期刊2013年7月CHEMICALRESEARCHhxyj@henu．edu．cnLigandsubstitutionreactionmechanismandtrans-effectofsquare。planarcomplexesZhao—wen，ZHANGWu，TENGHong—mei(CollegeoJChemistryandChemicalEngineering，HenanUniversity，Kaifeng，475004，Henan，China)Abstract：Thecauseoftrans—effe

2、ctforsquareplanarcomplexeshaspuzzledpeoplefornearly3century．Basedonthefactthattheligandsubstitutionreactionsofsquare—planarcomplexesre—actbyaSN2mechanism，themostpreferableconfigurationsfortheintermediateandtransitionstate2werededucedwhiletherepulsionsbetweentheligandsinthere

3、actionpathwaywereconsidered．Furthermore，thecausesoftrans—effectwererevealed，andanewtheory——ligandrepulsiontheorywasproposedtoillustratethetrans—effect．Itwasfoundthatas—proposedtheorycanbewelladoptedtoindependentlyandsystematicallyexplainthetrans—effectforallkindsofmonodentat

4、eligands．Keywords：square—planarcomplex；substitutionreaction；reactionmechanism；trans—effectCLCnumber：()641Doeumentcode：AArticleID：1008—101】(20】3)04一O33]一O5平面正方形配合物取代反应的机理和反位效应于I文，张武，滕洪梅(河南大学化学化工学院，河南开封475004)摘要：平面正方形配合物反位效应的起因已经困惑了人们将近一个世纪。作者根据平面正方形配合物取代反应的缔合机理，考虑了配体取代反应进行过程中

5、配体问的排斥作用，分析了最易形成的中间体和过渡态2的空间构型；揭示了反位效应的起因，提出了一种配体排斥理论，从而比较系统和圆满地解释了平面正方形配合物取代反应的反位效应。关键词：平面正方形配合物；取代反应；反应机理；反位效应In1926，CHERNYAEVdiscoveredthattheligandsubstitutionreactionsofsquareplanarPt(II)com—plexesfollowthetrans—effectrule；thatis，thereactivityofoneligandinthecomplexisre

6、latedtothena—tureofthetrans—positionligand．Undertheguidanceofthetrans—effectrule，manynovelPt(II)complexeshavebeensynthesized，andsomeofthemhavebeenfoundtoexhibitantitumoractivity[．Thisaddstotheoreticalandpracticalsignificancetounderstandthecauseoftrans—effect．Forthispurpose，s

7、everaltheories，includingFPHHBEPF’Selectrostaticpolarizationtheory，CHATT’S丌一bondingtheory，andBE—NERJEA’Sdissociationtheory。havebeenproposedtoexplainthetrans—effectrule[一．Amongthem，dissociationtheoryisnowrarelymentioned，becauseitdoesnotconformtothegenerallyacceptedassociationm

8、echanism．Electrostaticpolarizationtheoryisonlyapplicabletod—ligands，while／l