| Since Omar Yaghi reported the first three-dimensional metal-organic framework?MOF?,MOF-5,in the year 1999,MOFs have obtained great development and attracted numerous attentions from scientists and structure chemists from all over the world.Compared to other inorganic materials such as zeolites,porous carbon and mesoporous silica,MOFs assess unique properties including ultrahigh BET surfaces and porousity,variable structures and topologies,tunable channels and functional frameworks and so on,which make MOFs great potential in widely applications like gas adsorption and separation,heterocatalysis,luminescent sensors,drug delivery,optics and magnesium.Designing and synthesizing novel MOF materials is still the hot spot for structure chemists,however,considering the complexity of coordination style of metal ions causing the variability of inorganic clusters and the diversity of connection modes of organic linker leading to the sophistication of topologies,structure predicting and designing are of great challenges.In order to work out this problem,three possible strategies have been come out.First is the so-called post-synthesis modification?PSM?.Specific function groups could be imported by ligand exchange without changing the connection modes.Second is the reticular chemistry.We can design and synthesize a series of isostructures by use of a series of similar linkers.Third is the supramolecular building block?SBB?assembly.Firstly SBBs could be synthesized by reacting metal ions and ligand and then SBBs assemble with organic linkers to form final framework.In this essay,we mainly research and synthesize the assembly of a few different MBBs and SBBs with metal ions or linkers,and obtain a series of novel MOFs successfully.We have synthesized a new dendritic pyrene-based multicarboxylic ligand and CuxIy cluster as MBBs and Cu3N6 clusters and NaxZny clusters as SBBs,and obtained 14 novel MOFs and invest their structures and properties in detail.The whole essay can be divided into four parts as follow:Firstly,anovelpyrene-basedmulticarboxylicligand,1,3,6,8-tetrakis?3,5-isophthalic acid?pyrene?H8TIAPy?,had been designed and synthesized and then reacted with Zn2+,Eu3+,In3+to obtain three novel MOFs,[Zn4?TIAPy???DMSO?2??H2O?4]??Guest??1?,[Eu2?H2TIAPy???H2O?4]??Guest??2?and[?CH3?2?NH2?+][In?H4TIAPy?]??Guest??3?,respectively.Compound 1 can take place solvent-induced single crystal-to single crystal transformation and during the process,the Zn in the structure could be exchanged by Cu completely.We further discuss the possible mechanism with theory calculation.In the structure of compound 2,each ligand possesses two uncoordinated carboxylic acid,thus compound 2 shows base resistance in certain content.By treating compound 2 with base,the fluorescence emission gradually occurs red shift.Theory calculations have been used for mechanism discussion.Compound 3 is a two-dimensional structure and each ligand has four uncoordinated carboxylic groups.Each layer interacts with each other by hydrogen bonds between the uncoordinated carboxylic groups.Meanwhile,compound3 is a semi-conductor and could catalysis the decompose of organic dyes under the irradiation of UV.The rate of decompose can be as high as 90%in four hours.Secondly,we choose CuxIy cluster as MBB,reacting with 4,5-dicyanoimidazole,and obtain five new MOFs,[Cu2?DCI?2]?MeCN??4?,[Cu4I4?DCI??HDEA?]?5,DEA=ethylenediamine?,[Cu4I4?DCI??HDPPA?]?6,DPPA=tripropylamine?,[Cu2I2?DCI??HDMP?]?7,DMP=2,6-dimethylpyridine?,[Cu16I16?DCI?4?HTMHDA?2?H2O?]?8,TMHDA=N,N,N',N'-tetramethylhexamine?under different conditions.Compound 4 shows excellent water stability and acid or base resistance.It can keep high crystallinity after soaking in water for one week and can keep still under a wide range of pH from 0 to 13.5.After changing the synthesis procedure slightly,we could obtain this material in a large scale within a short time.The mild synthesis condition,excellent water stability and acid and base resistance make this material great potential in industrial applications.Meanwhile,we could get four new compounds 5,6,7,8 after adding different organic amines.They possess different space groups and channel structures.The sizes of channels match with those of the amines,indicating the template effect.We make use of theoretical calculation to compare the host-guest interactions.Thirdly,the Cu3N6 cluster has been synthesized by reacting pyrazole with Cu?NO3?2,and then assemble this cluster with H2BDC and adipic acid to obtain four novel structures,[Cu3??3-OH??pz?3?BDC?1.5?DMF?]?HDMA??DMF?2?H2O??9,pz=pyrazole?,[Cu3??3-OH??pz?3][Cu3??3-O??pz?3]?BDC?1.5[Cu?BDC??H2O?]?10?,[Cu3??3-OH??pz?3]?apd??EDA?0.5?EtOH??11,apd=adipic acid,EDA=ethyldiamine?,[Cu3??3-OH??pz?3]?apd??12?,with the stepwise strategy successfully.In the structure of compound 9,the Cu3N6 cluster remains and assembly with the ligand.In the structure of compound 10,the Cu3N6 cluster dimerizes into Cu6N12 cluster and assembly with ligand consequently.This structure possesses many vacant metal sites and can interact with CO2 firmly,leading to the good selective sorption capacity.In compound 11,the Cu3N6 cluster polymerizes into one-dimensional?Cu3N6?n chain.In compound 12,Cu3N6 assembly with adipic acid to form a novel dodecahedral cages and the connection of the cages forms complicated three-dimensional structure.Finally,reacting NaN3 with MeCN forms 5-methyltetrazole and then react with Na and Zn ions by in-situ reaction to get two multinuclear MOFs,Zn2Na4?L?6?NO3?2?13,L=5-methyltetrazole?,Zn18Na27?L?51?NO3?12?14?.In compound 13,Na20?NO3?12cluster forms a dodecahedral cage and the cage assembly further to form a larger dodecahedral cage Zn12Na8?L?30.This Zn12Na28?L?30?NO3?12 cage-in-cage structure is relatively rare in MOFs.Then the forty-nuclear giant cages connect with other eight cages to form a body-center cubic structure.In compound 14,the connection of the ligand,Na and Zn forms a giant thirty-nuclear spindle-shaped cage.The cage packs with each other by shared face along the axis of the spindle and shared edge perpendicular to axis,thus forming a complicated structure. |
PDF Full Text Request