The Design, Synthesis, Structure And Characterization Of Supramolecar Coordination Polymers Based On 2-amino-5-sulfobenzoic Acid

In this paper, we choose 2-amino-5-sulfobenzoic acid (H2asba) as the main ligand to react with transition metal ions Co(II)(d7)/Cu(II)(d9)/Cd(II)/Zn(II)(d10) in the presence of N-containing auxiliary flexible ligands, N,N’-bis(4-pyridyl)methylurea (4bpmu), 1,4-bis(triazol-l-ylmethyl)benzene (bbtz) etc, leading to the formation of fifteen supramolecular coordination polymers by adopting different synthetic methods. The influences of reaction temperature, central metal ions, the auxiliary ligands and solvent on the crystalline architectures of complexes have been discussed. All the complexes were characterized by single-crystal X-ray diffraction analysis, FT-IR, PXRD, thermogravimetric analysis and the diffuse reflectance UV-Vis-NIR spectra etc. The fluorescence properties of d10 [Cd(II)/Zn(â…¡] coordination compounds have been studied. The potential use of some d10 complexes as the fluorescent probe for some metal ions and nitroaromatic compounds has been investigated. The structure-property relationship is further discussed.The work consists of the following three parts:1. The self-assembly between 2-amino-5-sulfobenzoic acid and the d7 metal ion Co(â…¡) in the presence of N-containing auxiliary ligands result in four coordination polymers. Complexes {[Co(asba)(bix)1.5(H2O)2]·2H2O}n (1) and{[Co(asba)(bbtz)1.5(H2O)2]·2H2O}n (2) exhibit similar 1Dâ†'2D polyrotaxane structure. Complex{[Co(asba)(bimb)]}n (3) contains 1D polymeric chain with two kinds of alternative rings, which further extend to a 3D supramolecular structure through Ï€-Ï€ stacking and hydrogen bonds. Complex{[Co(asba)(4bpmu)]}n (4) exhibits a 3D framework structure with Schlafli symbol 33.46.52.64. The asba2" ligand adopt monodentate coordination mode in 1 and 2, chelating coordination mode in 3 and 4. The dehydration/rehydration behaviors of 1 and 2 have been studied. Gas sorption properties of the complex 1 have been explored.2. Four supramolecular coordination polymers were obtained through the assembly between 2-amino-5-sulfobenzoic acid and the d9 transition metal ion Cu(II) in the presence of the N-containing auxiliary flexible ligands. In complex{[Cu(asba)(3bpme)0.5(H20)]·H2O}n (5), Cu(II) is linked by the ligand asba2- as well as the auxiliary flexible ligand 3bpme, resulting in a 2D wave-like layer. Complex{[Cu(bth)2(H2O)2]·2(Hasba)·2H2O}n (6) consists of two lattice Hasba- anions and exhibits polymeric chain structure, which further extends into a 3D supramolecular network through hydrogen bonds. Complex{[Cu2(asba)2(mbix)2(H2O)2]·H2O}n (7) exhibits a 3D network structure with Schlafli symbol 33.43.54.64.7, in which the asba2"-bridged 2D layer was linked by the auxiliary ligand mbix. Complex {[Cu2(asba)2(obix)2(H2O)2]#3H2O}n (8) is a dinuclear complex, which further extends into a 3D supramolecular network through the hydrogen bonding. The ligand asba2" in 5,7 and 8 shows rich coordination modes. The solid state diffuse reflectance UV-Vis-NIR spectra of 5-8 were studied. The reversible dehydration/rehydration behaviors have been observed in 5-8.3. Seven supramolecular coordination polymers were successfully synthesized through the assembly between the acid 2-amino-5-sulfobenzoic and d10 transition metal ions Zn(II)/Cd(II) in the presence of the N-containing auxiliary ligands. The structure of complex {[Zn(asba)(bbtz)1.5(H2O)2]·2H2O}n (9) is similar to those of complexes 1 and 2. Complexes {[Zn(asba)(4bpmu)]}n (10) and{[Cd(asba)(4bpmu)}n (14) exhibit the similar crystal structure to that of complex 4. Complexes{[Zn(asba)(mbix)]}n (11) and {[Zn(asba)(mbix)2(H20)]·H2O·DMF}n (12) exhibit different structure, which are obtained under different reaction temperature. Complex 11 exhibits 2D layered structure, further extending into a 3D supramolecular network. The auxiliary ligand mbix in complex 12 link the Zn(II) ions into a helical chain, in which the asba2" anion only acts as a monodentate ligand. Complex {[Cd(Hasba)2(4bpme)2(H2O)2]·4bpme·4H2O}n (13) is a mononuclear unit, which further extends into a 3D supramolecular architecture through the hydrogen bonding and Ï€...Ï€ stacking interactions. Complex{[Cd(asba)(bbtz)1.5(H2O)]·2H2O}n (15) shows a three-fold interpenetrated 3D framework architecture in which the asba2- ligand acts as the pillar. The potential use of the complexes 9,11,12,14 and 15 as the fluorescent probe for some metal ions and nitroaromatic compounds has been investigated in detail. The desolvation/resolvation behaviors of 9,12,13 and 15 have been explored. The desorption/adsorption to gases of complex 15 has been studied.