Molecular Clusters Of Solid And Liquid Structure Information Relevance,Assembly Of Process And Reaction After Modification Based On 2-(hydroxymethyl)quinolin-8-ol

Although the fundamental speciation process underlying the formation of low nuclearity cluster-based compound is well understood,the process by which larger structures are formed is not clear due to the large library of building blocks,fragments,and clusters potentially available as the number of metals within a building block increases.The accurately detection of these species in solution remains a great challenge,which is essential for further exploration of the formation and possible applications of such clusters.In this thesis,We use a three-site chelating ligand 2-(hydroxymethyl)quinolin-8-ol with Ni2+ ions in solvents,to build an octanuclear cluster compound.It was followed by a comprehensive study of its formation process using electrospray mass spectrometry in solution which provides the self-assembly mechanism.Further studies involved the post-synthetic modifications of this compound.This thesis is divided into three chapters:The first chapter introduces the subject of interest where the system introduced involved the supramolecular chemistry and complex modifications which are research hotspot.It includes the latest progress of ligands in-situ reaction and problems that are encountered.At the same time,we introduced the application of ESI-MS technique in solution chemistry of coordination complexes,which provides new ideas and new methods for the study of clusters.In chapter 2,the synthesis of an octanuclear compound,[Ni8(Hhmq)8(mtz-H)2(N3)2Br4·7CH3CN](1),using a three-site chelating ligand,2-(hydroxymethyl)quinolin-8-ol,in the presence of azide in acetonitrile is described.Due to the in-situ reaction of the latter two the central methyl tetrazolium template is generated under the condition.The analogous chloride complex,[Ni8(Hhmq)8(mtz-H)2(N3)2Cl4·7CH3CN](2),is also synthesized in a similar manner.The presence of the Ni8 clusters in methanol or mixed solvent of DMSO was demonstrated using high-resolution ESI-MS and their physical behaviors were studied.We found that the Ni8 clusters are stable in the above two solvents with peaks in the mass spectra at 1134.98,which corresponds to the species[Ni8(Hhmq)8(mtz-H)2(N3)2Br2]2+.The results indicate the Ni8 clusters retain the main framework in different solutions.The stabilities of the Ni8 clusters were confirmed by further tests using CSI-MS.Knowing that Ni8 crystals is stable in various solvents we proceed with ESI-MS to track Ni8 cluster formation process,and found that the strongest ion peaks are located at m/z=623.04,1245.09 and 1343.01,where these species contain the[Ni4(Hhmq)4(mtz-H)(N3)]fragment.This particular result evidences that[Ni4(Hhmq)4(mtz-H)(N3)]2+is an importance intermediate in the formation of the Ni8 cluster.The successful elucidation of the multi-core cluster compound assembly process and its reaction mechanism provides methodology for building large clusters with novel structures and special functions.We also tested the chemical stability of Ni8.X-ray powder diffraction shows that under the high temperature and pressure Ni8 powder diffraction patterns remain unchanged;ESI-MS showed that under high temperature and pressure Ni8 retains its structure.The work of this chapter provides the precursor for the next chapter research.The third chapter describes the post-synthetic modification of the Ni8 compounds.We firstly use the Ni8 compounds as raw materials to form adducts with extra metal ions by varying the conditions of temperature and pressure.Two new compounds with deccanuclear,structures,[Co2Ni8(Hhmq)6(H2hmq)2(mtz-H)3(N3)2Cl5·4CH3CN],and[Co2Ni8(Hhmq)6(H2hmq)2(mtz-H)2(tz-H)(N3)2Cl5]were obtained.The two decanuclear compounds contain the Ni8 cluster as the base and have the asymmetric captured[Co2(mtz-H)Cl4]-and[Co2(tz-H)Cl4]-on its periphery The crystals were structurally analyzed and the causes of the asymmetric capture is due to the size constraint where the two halves are pulled on coordination of the[Co2(mtz-H)Cl4]-and[Co2(tz-H)Cl4]-units.The thermal stabilities of the decanuclear compounds are also reported.Electrospray mass spectrometry(ESI-MS)was used to study the solution behavior of[Co2Ni8(Hhmq)6(H2hmq)2(mtz-H)3(N3)2Cl5-4CH3CN](3).The MS spectra of 3 display peak at m/z of 1096.04 which corresponds to[Ni8(Hhmq)6(H2hmq)2(mtz-H)3(N3)2]2+(fitting:m/z=1096.02).It suggests the adduct can easily lose the[Co2(mtz-H)Cl4]under the MS conditions.Finally,the Ni8 cluster is found to capture the nitrogen heterocyclic methyl tetrazolium from solution under the condition of mass spectrometry and displays a peak at m/z of 1139.05,which corresponds to the adduct,[Ni8(Hhmq)8(mtz-H)2(N3)2(mtz-H)(OH)(CH3OH)(H2O)]2+.In the case of tetrazolium Ni8 framework picks one to give peak at m/z of 1125.02,corresponding to[Ni8(Hhmq)8(mtz-H)2(N3)2(tz-H)(OH)(H2O)3]2+.The ability of Ni8 clusters to associate with some organic ligands under MS condition in solution may provide a way to generate adducts of higher nuclearity and may be used for purification.Using coordination clusters in post-synthetic reaction is the new level function regulation,after the multi-step series reaction depends on good design concept,and rational inorganic-organic combination strategy,which is a complex research of major challenges.