| The design and synthesis of functional coordination polymers (CPs) is attracting much attention for their extensive application in gas adsorption and separation, magnetism, fluorescent and electronic materials, catalysis, etc. Recently, N,N’-dipyridyldiamides have aroused great interest ascribed to the following advantages:(1) the pyridyl groups exhibit strong binding ability toward transition metal ions; (2) the length between the pyridyl groups is tunable; (3) the amides functionality can be either hydrogen bonding donor or acceptor to promote host - guest interactions. In this thesis, we choose N,N’-di(3-pyridyl)succinamide (L) to associate with transition metal ions in the presence of polycarboxylic acids to give a series of CPs with diverse structures. According to the structure characteristics of these CPs, we study the fluorescent properties, adsorption toward organic dyes, photocurrent response and catalytic properties. The key results are briefly summarized as follows:1. The CP of [Zn(1,2,3-BTA)(H2O)]·(H2L)0.5·2H2O (1·2H2O) is prepared via the reaction of L with Zn(OAc)2·2H2O in the presence of 1,2,3-benzenetricarboxylic acid hydrate (1,2,3-H3BTA). Compound 1·2H2O features a Zn-based 1D anionic structure supported by 1,2,3-H3BTA ligands, leaving L doubly protonated and functions as a counterion to balance the charge. Compound 1·2H2O is highly selective toward Congo Red (CR) adsorption (1129 mg·g-1). Instant adsorption of CR by 1·2H2O leads to the formation of a unique Cp-dye composite 1·0.75CR·6H2O, which demonstrates remarkably enhanced photocurrent response compared to that of its precursor.2. From the 1D coordination polymer of 1·2H2O, two homo-or hetero-metallic 2D coordination polymers [Zn3L(1,2,3-BTA)2(H2O)6]·4H2O (2·4H2O) and [Zn2CoL(1,2,3-BTA)2(H2O)6]·4H2O (2c·4H2O) are prepared, by taking advantage of the unsaturated coordination of three carboxylates of 1,2,3-BTA in 192H2O, coupled with the potential coordination of the L ligand. Compounds 2·4H2O and 2c 4H2O are also possible through direct metal-ligand assembly. By the direct reaction, [Zn2.76Coo.24L(1,2,3-BTA)2(H2O)6]·4H2O (2a·4H2O) and [Zn2.4oCoo.6oL(1,2,3-BTA)2(H2O)6]·4H2O (2b·4H2O) are accordingly prepared to demonstrate the universality of hetero-metallic doping. Compounds 2·4H2O,2a·4H2O-2c-4H2O are 2D CPs formed by linking [1,2,3-BTA]-based 1D chains by L ligands. Within the 2D polymer matrices, there are two types of coordination environments for metal ions and the doped Zn(Ⅱ)/Co(Ⅱ) can only access one site, which means that the doping is site-selective. Increasing the Co content causes the quenching of photoluminescence and the improvement of photocurrent responses.3. Using Zn(OAc)2, L and polycarboxylates, seven coordination polymers, namely {[Zn(1,3,5-HBTA)(L)0.5(H2O)]·H2O}n, (1,3,5-H3BTA=1,3,5-benzenetricarboxylic acid) (3),{[Zn(1,3,5-HBTA)(L)0.5(H2O)2]H2O}n (4), [Zn(1,2,4,5-BTCA)0.5(L)0.5]n (1,2,4,5-H4BTCA=1,2,4,5-benzenetetracarboxylic acid) (5), [Zn(4,4’-CDBA)(L)]n (4,4’-H2CDBA=benzophenone-4,4’-dicarboxylic acid) (6), [Zn(5-MPA)(L)]n (5-H2MPA=5-methylisophthalic acid) (7),{[Zn(4-MOPA)(L)]·0.5H2O}n (3-H2MOPA= 4-methoxyisophthalic acid) (8) and{[Zn(4-NPA)(L)]0.5H2O}n (4-H2NPA= 4-nitroisophthalic acid) (9) have been synthesized hydrothermally and characterized by IR, element analysis and X-ray single crystal diffraction. In compound 4, the [1,3,5-HBTA]2-ligand is the hydrolysis product of 5-H2CPA (5-H2CPA=5-cyanoisophthalic acid). Compounds 8 and 9 feature ID chain structures whereas 3,4,6 and 7 are 2D layer networks, and compound 5 exhibits a 3D network. The different coordination modes of polycarboxylates and conformations of L play decisive roles in affecting the coordination geometry of metal cation and the structural outcome of these complexes. There are two types of coordination geometries for the central metal Zn(Ⅱ). In 3,6,7,8 and 9, the Zn(Ⅱ) ions adopt a distorted tetrahedral geometry; while in 4 and 5, the Zn(Ⅱ) ions exhibit a slightly distorted square-pyramidal geometry. The Zn(Ⅱ) ions in 4 and 5 can be partly substituted by Co(Ⅱ) ions to generate hetero-metallic congeners of 4a and 5a. Further catalysis experiments demonstrated that 2c,4a and 5a are active toward the formation of n-tert-butyl-benzo[d]oxazol-2-amine by the insertion reaction between 2-amino phenol and n-butylisocyanide.4. Reactions of L with AgOTf, AgTFA and AgNO3 (OTf=triflate, TFA= trifluoroacetate) produce three CPs of [Ag(L)(OTf)·DMF·MeCN]n (10·DMF·MeCN), [Ag(L)(TFA)·2H2O]n (11·2H2O) and{[Ag(L)]2(NO3)2}n (12). In 10·DMF·MeCN, two 1D [Ag(L)] chains are joined by the Ag…Ag,π…π and hydrogen-bonding interactions to form a 1D double chain structure, which is further linked to other equivalent ones via the hydrogen bonding interactions to yield a 3D structure. In 11·H2H2O, the 1D [Ag(L)] helical chains are connected by the Ag…O,π…π, C-H…π and hydrogen-bonding interactions to afford a 3D framework. In 12, two kinds of 1D [Ag(L)] chains are linked by the Ag…O and hydrogen-bonding interactions to form a 3D structure. The luminescent properties of 10-12 along with L are also investigated. |
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