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Three novel metal–organic frameworks (MOFs) photocatalysts with different structures [Cd(4-Hptz)2(H2O)2Cl2](4-Hptz = 4-(1H-tetrazol-5-yl)-pyridine) (1), [Cu(btx)2(ClO4)2]n(btx = 1,4-bis(triazol-1-ylmethyl)benzene) (2), and [Cu(btx)(ClO4)]n (3) have been synthesized by solvothermal reaction successfully. All samples were characterized by X-ray, FT-IR, XPS and UV–Vis diffuse reflectance spectra. The photocatalytic properties were investigated by degradation of methylene blue (MB) dye and reduction of Cr(VI) to Cr(III) in aqueous solution under UV light. Control experiments show that the pH value is vital for Cr(VI) reduction, and meanwhile, the use of hole scavenger of methanol promotes the photocatalytic reduction significantly. It has been also demonstrated that photocatalysts 1 and 2 are efficient for MB degradation. The cyclic experiments indicated three photocatalysts are stable and reusable, enabling them to be the potential candidate in environment governance.

Four new complexes of Robson-type macrocycles, [CuH(L1)]2(ClO4)2(H2O)2 (1), [CuH(L2)] ClO4 (2), [Cu H(L3)]2(ClO4)2 (3), [Cu H(L4)]2(ClO4)2(CH3CH2OH)2(CH3CN)2(4) and two reported Robson-type macrocycles polymers {[CuL5](H2O)2}n(5), {[MnL5](H2O)2}n (6) were obtained. The ligands (H2L1, H2L2, H2L3) are the products from the condensation between bata and N,N′-bis(3-formyl-5-X-salicylimine)-1,2-ethylenediimine (X = CH3, Cl, F), respectively. Ligands H2L4 and H2L5 are the products of N,N′-bis(3-formyl-5-methylsalicylimine)-1,2-propylenediimineand condensation with bafa and bapa, respectively. All the metal ions have unsaturated coordinated sites, which are available for NO binding. The binding of the complexes with NO molecules have been confirmed by UV–Vis spectrophotometry. The binding constants were calculated to be 1.28 × 103 M−1, 8.9 × 102 M−1, 7.7 × 103 M−1, 1.2 × 103 M−1, 1.2 × 103 M−1, 1.3 × 103 M−1 for 1, 2, 3, 4, 5 and 6, respectively. The control experiments revealed there was non-reversible binding of NO, which can be ascribed to specially coordination environment of the central ions. Moreover, the interactions of the complexes with calf thymus DNA (CT-DNA) have been measured by agarose gel electrophoresis, and unobvious DNA cleavage ability of complexes 1, 3 and 4 indicating no damage to DNA. The results reveal that complexes 1, 3 and 4 can be served as potential NO scavengers.

The synthesis, crystal structures, and magnetic properties of a nonanuclear dysprosium complex [Dy9(μ3-OH)8(μ4-OH)2(N3)8{(py)2C(OCH3)O}8](OH)·4H2O (1, (py)2C(OCH3)OH = the hemiacetal form of di-2-pyridyl ketone) and a tetranuclear dysprosium complex [Dy4(μ4-O)(μ-N3)2(μ-OCH3)2(L)4](OH)2·3.5CH3OH (2, HL = 2-(benzothiazol-2-yl-hydrazonomethyl)-6-methoxyphenol) have been prepared and structural characterization. Nine DyIII ions in 1 form a sandglass with the eight DyIII atoms at the apexes and one DyIII ion located at the center of a square antiprism formed by eight DyIII ions, while four DyIII ions in 2 form an irregular tetrahedron. Complexes 1 and 2 have been investigated by direct current (dc) and alternating current (ac) susceptibility measurements. The ac susceptibility studies revealed that complexes 1 and 2 exhibit slow magnetic relaxation. Moreover, complex 2 shows two-step thermal magnetic relaxation with their energy barriers of about 15 K and 2.68 K, respectively. The orientations of the magnetic anisotropy of DyIII ions in 1 and 2 were also estimated by electrostatic calculations.

Three dinickel(II) macrocyclic complexes [Ni 2 L(μ-OAc)]ClO 4 •X (L = L 1 , L 2 and L 3 ) with two 2-thiophenoethyl pendant arms, have been synthesized by cyclocondensation between N , N -bis(3-aminopropyl)-2-thiophenoethylamine and 2,6-diformyl-4-R-phenol (where R = Me, Cl and F and X = MeOH, 2MeCN and H 2 O, respectively), in the presence of nickel(II) ions. The complexes were characterized by elemental analysis, spectroscopic methods and X-ray diffraction techniques. The geometry around both of the Ni(II) ions in each molecule is a slightly distorted octahedral and the thiopheno groups do not coordinate to the Ni(II) ions, resulting that the complexes display contorted saddle-form configurations. The distances between the Ni⋯Ni centers for the complexes are 3.145, 3.171 and 3.155 A, respectively. The influences of the substituted groups R in the benzene rings of the macrocyclic units on the structure, electrochemistry, magnetism, cleavage and antibacterial property to DNA have been investigated. The ES-MS results of the complexes confirm that [Ni 2 L] 2+ species in methanol solution are very stable because all the peaks in ES-MS spectra contain this kind of units. The reduction potentials of the complexes shift towards anode upon increasing the drawing electronic ability of substituted groups. Magnetic measurements in the 2–300 K range indicate weak antiferromagnetism for the dinuclear Ni(II) complexes and the magnetic exchange interactions enhance with the decrease of the Ni–Ni distances. These complexes exhibit cleavage activities towards plasmid pBR322 DNA and antibacterial activities.

Two new isomorphous tetranuclear complexes [Cu4L2(4,4′-bipy)2]·(ClO4)4·2CH3CN·2H2O (1) and [Zn4L2(4,4′-bipy)2]·(ClO4)3·CH3O·4H2O (2) have been obtained and fully characterized (where bipy = bipyridine, H2L = macrocycle is the [2+2] condensation product of 2,6-diformyl-4-fluoro-phenol and 1,4-diaminobutane). They exhibit wheel-like configuration in which two 4,4′-bipy molecules connect two dinuclear [M2L]2+ units. The interactions of the complexes with calf thymus DNA were studied by UV–Vis and CD spectroscopic techniques. The binding constants of 1 and 2 are 2.27 × 106 and 3.89 × 105 M−1, respectively. The magnetic measurement of 1 reveals that there are strong antiferromagnetic coupling (J = –272.6 cm−1) between two Cu(II) ions in the macrocyclic unit and ferromagnetic interaction (j′ = 41.7) between the Cu(II) ions in two adjacent macrocyclic units. Furthermore, the cyclic voltammogram of 1 shows that it undergoes two quasi-reversible processes with the half wave potentials –0.232 and –0.606 V, respectively.

Two new coordination polymers of Robson-type macrocycles, [Cu2L1(μ-ClO4)2]∞ (1) and [Cu2L2(μ-ClO4)2]∞ (2) (where H2L1and H2L2 are the [2+2] condensation products of 2,6-diformyl-4-flurophenol with 1,3-diaminopropane and 2-hydroxy-1,3-diaminopropane, respectively), have been synthesized and characterized. The intriguing feature is that intermolecular perchlorato bridges occur between adjacent copper(II) centers. The cyclic voltammograms of the complexes show that each complex undergoes two pseudo-reversible processes with the half wave potentials, −0.361 V and −0.729 V for 1, and −0.372 V and −0.744 V for 2, respectively. Magnetic susceptibility was measured for 1 and 2 over a temperature range of 2–300 K. The optimized magnetic data were J = −359.6 cm−1, j′ = −30 cm−1 and R = 6.8 × 10−8 for 1 and J = −411 cm−1, j′ = −26 cm−1 and R = 2.4 × 10−7 for 2, respectively. The data reveal antiferromagnetic couplings between the copper(II) ions of intra- and intermolecular units.

Three dimetallic complexes of the unsymmetrical macrocycle (L)2−, [M1M2L]2+ (M1M2 = NiNi, CuZn, CuCd), have been synthesized by cyclocondensation between N,N′-bis(3-formyl-4-n-butylsalicylidene)ethylenediimine and 1,3-diaminopropane in the presence of M 1 2 + and M 2 2 + .The crystal structure of the complex [Ni2L4(H2O)2](ClO4)2 · 0.5CH3OH was determined by X-ray diffraction techniques.The asymmetric unit contains two complete macrocyclic complexes which are nevertheless quite similar to one another.The nickel–nickel separations, bridged by the two phenoxides, are 2.977 A and 2.982 A.In each molecule, the Ni(II) located in the ethylene chain linked site has a square planar geometry whereas the Ni(II) located in the propylene chain linked site has an octahedral environment.The results of ES-MS and cycle voltammograms confirm that Cu–Zn, Ni–Ni form stable complexes with the macrocyclic ligand L, however the complex composed of Cu–Cd was unstable, and easily lost Cd2+ from the complex in methanol solution.The cyclic voltammograms of the complexes show that each complex undergoes a stepwise reduction process, e.g.[Ni2L]2+ with E 1 / 2 1 = - 0.862 V and E 1 / 2 2 = - 1.20 V .Magnetic measurements in the 2–300 K range indicate weak antiferromagnetism for the dinuclear nickel(II) complex with the exchange constantJ = −0.90 cm−1.

A novel saddle-form macrocyclic barium complex was synthesized by cyclo-condensation of diformylpyridine with [BaL1(ClO4)2]·3H2O. In the complex crystal [BaL2(ClO4)2(H2O)]·MeOH·1.5H2O, two perchlorate anions are cis-coordinated to barium(II), and the coordinated water molecule is located on the opposite side to the perchlorate anion. 1H NMR and ES MS spectra were used to characterize its structure in methanol solution. The mechanism of the reaction was discussed.

Three alkaline earth metal cryptates (Barium(II), Strontium(II), Calcium(II)) were synthesized by (2+3) template condensation of tris(3-aminopropyl)amine with 2,6-diformylpyridine and characterized by some physical methods. The solution structure of [BaL]2+ (L=cryptand) was studied by electrospray mass spectrometry, 1H-13C NMR and molecular dynamics method based on analysis of 1H NMR NOE spectrum. The crystal structure presents a tricapped trigonal prism structure in which barium(II) is enclosed within the macrobicycle and is nine-coordinated by six imino nitrogen atoms and three pyridyl nitrogen atoms.