Synthesis And Application Of Functional Block Molecules

Molecular building blocks(MBBs)are fundamental units for the synthesis of specific functional materials.Complex and diverse functional materials can be realized by specific design and thesis of functional MBBs and controlled self-assembly processes.Thisthesis mainly focuses on the synthesis of functional MBBsand applications of MBBs for the construction of conjugated microporous polymers(CMPs)catalysts,the assembly of single-molecule devicesand the growth of multivariate surface mounted MOFs(MTV-SURMOFs).The main contents of this thesiscan be devided into three parts as showd following:(1)The reaction of 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl(4-NH2-TEMPO)with 2,5-dibromobenzoic acid resulted in TEMPO functionalized organic monomer,2,5-dibromo-N-(2,2,6,6-tetramethylpiperidine)-benzamide.The Sonogashira-Hagihara coupling reaction of 2,5-dibromo-N-(2,2,6,6-tetramethylpiperidine)-benzamide with1,4-diethynylbenzene,1,3-diethynylbenzene,and1,3,5-triethynylbenzene,resulting in the formation of three TEMPO radical decorated CMPs,named CMP-1-TEMPO,CMP-2-TEMPO,and CMP-3-TEMPO,respectively.The chemical composition and structural information of CMPs-TEMPO were characterized by FT-IR,XRD,EPR spectraand SEM.Moreover,the catalytic activity of the above CMPs-TEMPO toward the selective oxidation of alcohols was examined and the results indicated that when reactions were carried out under O2 atmosphere,temperature 80 oC,trifluorobenzene as solvent,and terbutyl nitrile(TBN)as co-catalyst,the all three CMPs-TEMPO enable selectively oxidize a broad range of alcohols,including primary and secondary aromatic alcohols,and heteroatom aromatic alcohols into their corresponding aldehydes and ketones.Among them,CMP-1-TEMPO show best durability that is after three cycles,the catalytic activity remains 80%,whil the catalytic activities of CMP-2-TEMPO and CMP-3-TEMPO significantly decreased(less than50%)after three catalytic cycles.The possible reason is that partially decomposition accurs during catalytic reaction leading to decreased catalytic active sites.(2)By using 4,4′-biphenyldicarboxylic acid and 4,4′-bipyridine as parent MBBs,electron-withdrawinggroups(e.g.,-NO2),electron-donating groups(e.g.,-NH2)andelectrochemical active group(e.g.,ferrocene)were incorporated onto their backbone as appended groups.The single molecular conductivity of thepyridine functionalized MBBs was measuredby scanning tunneling microscope break junctionmethod(STMBJ).The results indicate that the single molecular conductivity of pyridine functionalized MBBs depends on many aspects,including the nature of appendant groups,steric hindrance,andtwistangle.(3)By using mixed-linker strategy together with layer-by-layer growth method,a familiy of [M2L2P] type MOF,denoted asmultivariated SURMOFs films(MTVSURMOFs)were grown onto pyridine-terminated Si-Au substrates.XPS and SEMwere employed to analyze the chemical compostionand morphology of the obtained MTV-SURMOFs.The results showed that mixed-linker strategy combined with layer-by-layer growth methodis an effective method to fabricate MTVSURMOFs.