Controllable Alkoxylation Of Anderson-type Heteropolyoxometalates And Their Catalytic Properties

POMs are an exceptional family of inorganic oxide anions consisting of Mo,W,V,etc.early transition metal ions at their highest oxidization states with structural versatility.The Anderson-type hetreopolyanions are one of the most important subclass since their most flexibility benefited from the central heteroatom.Among the frontier of current POMs investigations,organic modification and functionalization of POMs stands for one of most hot topics.The organic modification of POMs can incorporate POMs with advanced functional organic moieties on their surfaces to make the structure versatility more accessible and the design of advanced functional materials more rational.Regarding the Organoalkoxylation,Triols as special alkoxo organic ligands have been widely applied for the stabilization and functionalization of different POM clusters including Anderson,Lindqvist,and Dawson structured POMs.Furthermore,based on POM-linker strategy,it is an effective strategy to incorporate POMs with advanced functional organic moieties on their surfaces to make the structure versatility more accessible and the design of advanced functional materials more rational.Based on previous researches,in this dissertation,a direct modification protocol was proposed and well developed for the controllable synthesis of single-side,symmetrically,asymmetrically triol-functionalized Anderson organic hybrids and the corresponding isomer with specific triol modification mode.The related reaction mechanism,spontaneous resolution,isomer transformation and catalytic property are further investigated.There are six parts in this work as follows:(1)Applying direct modification protocol for the synthesis of single-side triol-functionalized Anderson ? isomer organic hybrids.Their intrinsic chirality was discovered and the spontaneous resolution of enantiomers occurred upon crystallization.(2)The ?2-O atom in Anderson-type POMs was pronated and became reactive site for the synthesis of single-side triol-functionalized Anderson ? isomer organic hybrids.Proton-controlled isomer transformation between the ? and ? isomer was discovered.This will open up a new era for controllable regioselective activation and further developing chemical reactivity of?2-O atoms in the Anderson cluster.(3)By excess proton addition,diol functionalization mode was discovered for the synthesis of single-sidetriol-functionalized Anderson ? isomer organic hybrids.Such diol functionalization mode not only works for some specific triol ligands but also can readily be extended to the diol ligands,which will greatly enrich the species of alkoxo-derivatized Anderson POM clusters.Such a proton introduced protocol may serve as a key option to control whether the ?,? or ? isomer will be generated.Besides extending special tripodal ligands with carboxyl group to symmetrically functionalized the Anderson cluster.Such Anderson organic hybrids cannot be obtained for the traditional reconstruction protocol.This has extended the versatility of tripodal ligands applied for Anderson-type POMs modification.(4)Through stepwise synthesis strategy,single-side ? isomer was utilized as a precursor to efficiently synthesized asymmetrically triol-functionalized Anderson organic hybrids.The as-prepared asymmetric hybrids are chiral,which can be used as potential synthons for developing POM-based chiral hybrid materials.(5)An isomer of the organically-derivatized “Anderson-Evans” heteropolyanions,which stands for the first example of the organically derivatized 1:6 heteropolyanions with the same peculiar butterfly-shaped topology as that of the heptamolybdate isopolyanion,a late-coming discovery pending for more than half a century.The obtained hybrid materials can serve as catalysts for selectively catalytic oxidation of KA oil with atom economy utilization of 30 % H2O2 under ambient conditions,to afford AA in high yield(93%)and high selectivity(97%)as well as incredible high TON of 9985.The route is economically feasible and competitive,eco-friendly,sustainable and promising at the same time for practical industrial AA production.(6)Applying triol-functionalized Anderson organic hybrids to catalyzed [4+1] cycloaddition reaction of cross carbon–heteroatom dehydrogenative coupling.It is a general,efficient and green approach toward diversified penta-heterocycle formation.These investigations has greatly enriched the category of Organoalkoxylation derivatives of Anderson cluster,Providing a reliable and convenient Synthetic methodology for the controllable design of triol-functionalized Anderson organic hybrids with specific and desirable functionalization modes which were the first time discovered in this dissertation.The versatility of tripodal ligands functionalized Anderson-type POMs modification mode will make the design of advanced functional materials more rational and leading the related investigations in the field of Organoalkoxylation of Anderson clusters.