Controllable Syntheses Of Porous Metal-organic Frameworks:Encapsulation Of Ln^Ⅲ Cations For Tunable Luminescence And Small Drug Molecules For Efficient Delivery

Two novel porous metal-organic frameworks (MOFs),[Zn3(L)(H2O)2]·3DMF·7H2O(MOF-1) and [(CH3)2NH2]6[Ni3(L)2·(H2O)6]·3DMF·15H2O (MOF-2), were synthesizedsolvothermally (H6L=1,2,3,4,5,6-hexakis(3-carboxyphenyloxymethylene)benzene). InMOF-1, six carboxylates of the L ligand show the same coordination mode: each carboxylategroup bridges two ZnIIatoms. In this way, four pairs of ZnIItrimers are linked by four Lligands to form a [Zn3L]4cubic cage with square windows of ca.11.0×11.0.Neighboring ZnIItrimers are linked by the backbones of L ligands to form a fascinating3D6-connected framework with the point symbol of (412.63)2. In MOF-2, eight L ligands bridgesix NiIIatoms to generate a rhombic dodecahedron [Ni6L8] cage. Each cage is surrounded byeight adjacent ones through sharing the carboxylate groups to yield an unusual3D porousframework. Idealizing the structure as a sphere, the diameter of MOF-2is ca.22.6and theinternal cavity size is ca.18.5×18.5. From the topological point of view, the L ligandcan be viewed as a6-connected node, and the NiIIatom can be regarded as a4-connectednode. Thus, the3D framework of MOF-2can be reduced to a binodal (4,6)-connected netwith the point symbol of (44.62)(46.89).The two porous metal-organic frameworks have been also characterized by elementalanalyses, infrared spectra (IR), X-ray diffractions and thermogravimetric (TG) analyses. Inaddition, the controlled pore size and the regular channels of MOF-1allow it application insome guest molecules adsorption. So the encapsulations of LnIIIcations for tunableluminescence and small drug molecules for efficient delivery were investigated for MOF-1indetails.