Metal-Organic Frameworks are interesting category of materials containing metal or metal cluster nodes and multitopic organic linkers. Tunability of cluster nodes and organic linkers offers infinite possibilities to design and synthesize variety of MOF structures with fascinating topologies and properties.
In this thesis, several Cd(II) and Zn(II) metal organic frameworks have been prepared from the reaction of Cd(II) or Zn(II) salts, benzene-1,3,5-tricarboxylic acid (H3BTC) or benzene-1,4-dicarboxylic acid (H2BDC), and three bis(pyridyl)-based linkers as pillar ligands under solvothermal condition or solvent layering methods. The compounds have been characterized by FT-IR spectroscopy, elemental analysis and PXRD. The structure of [Cd3(BTC)2(4-bpdb)2]n (4-bpdb= 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) has also been characterized by single crystal X-ray diffraction. Crystallographic result shows a 3D structure with a single complex net which can be simplified as two interpenetrated sqc27 net with a point symbol of {4.62}2{42.610.83}. The capability of the MOFs in adsorption of Congo red (CR) and Neutral red (NR) organic dyes together with kinetics and thermodynamics of adsorption have been investigated in detail. In addition, conversion of the 3D architecture of Cd- or Zn-MOFs into the nano-sized CdO and ZnO particles have also been studied.
Our attempts in preparation of Zn(II) mixed ligands MOFs by the reaction of Zn(II) salts, H3BTC and three bis(pyridyl)-based linkers under different reaction conditions were failed and only known structures of [Zn(BTC)](H2NMe2).DMF]n and [Zn3(BTC)2(H2O)3]n were isolated.
.
 

Coordination polymers (CPs) and metal−organic frameworks (MOFs) are considered as promising materials for many potential applications. The Structure of these compounds are controlled by a variety of factors including the coordination preference of the metal ion, the nature of the bridging ligand, coordinating ability of the counteranion, and choice of crystallization solvent.
In this thesis, five new silver(I) coordination polymers {[Ag(μ-bib)1.5](SO3CF3)•(CH3CN)0.5}n (1), {[Ag(μ-bib)](NO3).(H2O)}n (2), {[Ag(μ-bib)]BF4}n (3), {[Ag(μ-bpb)2]NO3}n (4), and {[Ag(μ-bdb)1.5]SO3CF3}n (5) (bib= 1,4-bis(imidazolyl)butane, bpb= 1,4-bis(pyrazol-1-yl)butane, and bdb= bis(3.5-dimethylpyrazol-1-yl)benzene have been prepared and fully characterized by FT-IR spectroscopy, X-ray powder diffraction (XRPD), elemental analysis, and single crystal X-ray diffraction.
In the structure of {[Ag(μ-bib)1.5](SO3CF3)•(CH3CN)0.5}n (1), silver(I) ions act as three connected nodes (3-c) and bib ligand act as linkers (2-c), forming two-dimensional honeycomb nets with large hexagonal windows. Unusual ABCDEFABCDEF packing mode of the hcb layers in the 3D packing is another feature of this structure. Compounds 2 and 3 have one-dimensional structures. 2 is a zig-zag chain polymer while 3 illustrate a double strand helical DNA-shaped structure. Connection of silver(I) ions with bidentate bpb and bdb linkers form two-dimensional coordination polymers of 4 and 5 with 44-sql and hcb nets, respectively. In all the complexes, triflate, nitrate and tetrafluoroborate anions remain uncoordinated. The bib and bpb ligands with –(CH2)4- spacer group display various conformations, showing different ligand lengths and dihedral angles.
Influence of different factors such as: counter anion, steric hindrance, spacer group of the linker ligands, solvent, and reaction conditions on the structure of resultant polymers have been investigated in detail. In addition, anion exchange property, structural transformation behavior and Mechanochemical synthesis of the complexes have also been studied.