Metal-organic Frameworks Based On W/S/Cu Cluster Units

The work of this thesis is focused on the studies of the performances of the W/S/Cu cluster units in building metal-organic frameworks(MOFs),and also guests absorption and exchanging properties,recognition and sensing of small molecules of the porous W/S/Cu units-based MOFs.Complexes 1,2,3 have similar structures,which contain hexanuclear cluster unit(WS4Cu5)3+,Va,where the five Cu+atoms show a quadrangular pyramidal arrangement around the WS42-anion.The Va unit is first been observed in a MOF and acts as a tetrahedral node in a diamondoid(dia)net.Nanotubes are formed within 4-fold dia nets with round-shaped cross-section of 6.6 × 6.6 ?.Complex 1x contains heptad-nuclear cluster unit(WS4Cu6)4+,?a,where the six Cu+ atoms show an octahedral arrangement around the WS42-anion.The ?a unit acts as a tetrahedral node in a dia net of complex 1x.Complexes 4 contains(WS4Cu3)+,?a cluster unit,where the three Cu+ atoms show a triangular arrangement around the WS42-anion.The ?a unit acts as a '?' shaped node and forms a 'zigzag' chain structure.Complexes 5 is constructed by a long ligand 4,4'-di(4-pyridyl)biphenyl(dpbp,15.7 A),which contains four anionic and four cationic frameworks,[WS4Cu3I2(dpbp)2]-n and[WS4Cu4(dpbp)2]n2+.More interestingly,the anionic net is formed by the tetranuclear(WS4Cu3I2)-,?a unit,the cationic net is formed by the pentanuclear(WS4Cu4)2+,?a unit,forming an unprecedent 8-fold non-equivalent interpenetrated structure[2+2+(2*2)].Large rhombus nanotubes with diagonal dimensions of?20×10? are formed within this highly interpenetrating framework.Complexes 6,7,8 have similar structures containing pentanuclear cluster unit(WS4Cu4)2+,IVb,which is isomeric to the ?a unit of complex 5.The ?b unit has not been used in building MOFs as SBU before this case,and it can be described as a quadrangular pyramidal Va cluster unit missing one Cu+atom in the basal plane.The ?b unit functions as a triangular node,and the tpt ligand functions as a triangular connector,giving rise to a framework with the overall topology related to the SrSi2(srs)net.Large cages with an inner-diameter of 11? are formed between the two srs frameworks,and the volume of one cage is about 930 ?3.The cages in the ab plane are connected by small channels with a cross-section of 3.2 × 3.8?,thus forming a two dimensional pores in the ab plane.The cages are large enough to incorporate many solvent guests,while the channels between cages are small,and it is difficult for some large solvents molecules going through.Complex 9 contains brick-wall like layer with a hexnuclear(WS4Cu5)3+,?b unit as SBU,which is a new type of W/S/Cu cluster unit and isomeric to the ?a unit of complex 1.The five Cu+ atoms are in one plane with the W atom forming a planar SBU.The ?b unit acts as a 'T'-shaped node in a brick-wall like layer structure.Complexes 10,11,12 have similar structures,which contain pentanuclear cluster unit(WS4Cu4)2+,?a,which acts as a tetrahedral node and forms a dia network.Square-shaped nanotubes with the inner cross-section of 5.4 × 5.3 A are formed within 6-fold interpenetrating frameworks.Strong C-H…N hydrogen bonds are formed between the paired dptz ligands of the interpenetrated networks with average C…N distance of 3.291(2)A,which stabilize the overall nanotubular architecture.The nanotubular architecture of 10 is stable after removing the solvent guests until 170?.X-ray analysis of the desolvated compound 10' revealed an intact nanotubular skeleton,but the pore size expands slightly to 5.7×5.3? and the cell volume increases by 1.5%.The C-H…N hydrogen bonds between networks are weakened in 10' with average C…N distance of 3.371(2)A.The DMF guests can be exchanged with other solvent molecules,CH3OH,C2H5OH,H2O,CHCl3,CH3CN and acetone,forming other inclusion compound 10?solvent with the host framework unchanged.When accommodating different solvent molecules as guests,the resulting inclusion compounds 10?solvent exhibit different colors depending on the solvent guests,representing a crystalline porous material with a solvatochromic behavior.And more interestingly,the band gaps of these solvent-included complexes 10?solvent are in linear correlation with the polarity of the guest solvents,and the solvent molecules can be sensed by the changes of UV-Vis spectra of the corresponding inclusion compounds,showing a new way of signal transduction as a new kind of sensor.