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Three Ni(II) complexes {[NiL(μ-OAc)(CH3CH2OH)]2Ni} (1), {[NiL(μ-OAc)(CH3OH)]2Ni]·2CH2Cl2·2CH3OH (2) and {[NiL(μ-OAc)(CH3OH)]2Ni}·1.5CH3OH (3) based on a Salamo-type bis-oxime ligand (H2L = 2,2′-[ethylenedioxybis(nitrilo-methylidyne)]dinaphthol) have been synthesized and characterized by physicochemical and spectroscopic methods. The complexes 1, 2 and 3 are all trinuclear structures, and the center Ni(II) ions are six-coordinated and show the slightly distorted octahedral coordination. They all consist of three Ni(II) ions, two deprotonated L2- units, two μ-acetato ligands and two coordinated solvent molecules, as well as the crystallizing solvent molecules. Although the molecular structures of the Ni(II) complexes 1, 2 and 3 are similar to each other, obtained in different solvents, the supramolecular structures are entirely different. The complexes 1, 2 and 3 possess the self-assembled infinite 1D, 3D and 2D supramolecular structures via different intermolecular interactions (hydrogen bonds, C–H···π and π···π stacking interaction), respectively. But complex 2 formed a 3D structures by intramolecular hydrogen bonds. It is significant that the solvent molecules have obvious effects on the optical properties and molecular configuration. The Hirshfeld surface analysis showed that the short-range forces of the hydrogen bonds in complexes 1, 2 and 3 accounted for 67.8%, 44.6% and 52.7%, respectively. The molecular orbital energies for ligand H2L and complex 1 were obtained by DFT calculation, and the electron distribution, energy level and energy gap of HOMO and LUMO were given.

Four new hetero-pentanuclear 3d–4f complexes [Zn4(L)2La(NO3)2(OEt)(H2O)] (1), [Zn4(L)2Ce(NO3)2(OMe)(MeOH)] (2), [Zn4(L)2Pr(NO3)2(OEt)(EtOH)] (3) and [Zn4(L)2Nd(NO3)2(OMe)(MeOH)] (4) were synthesized by the reactions of a newly synthesized octadentate bis(salamo)-based tetraoxime ligand (H4L) with Zn(OAc)2·2H2O and Ln(NO3)3·6H2O (Ln = La, Ce, Pr and Nd), respectively, and characterized via elemental analyses, FT-IR, UV-Vis spectroscopy and single crystal X-ray crystallography. The X-ray crystallographic investigation revealed that all ZnII ions were located in N2O3 coordination spheres, and possessed a trigonal bipyramid coordination environment. The LnIII ion lay in an O8 coordination sphere, and adopted a distorted square antiprismatic coordination environment. Furthermore, supramolecular interactions and fluorescence properties were investigated.

Two newly di- and tri-nuclear Cu(II) and Ni(II) complexes constructed from a half-salamo chelating ligand (HL: 2-[O-(1-ethyloxyamide)]oxime-6-methoxyphenol), [Cu2(L)2(μ-OAc)2] (1) and [{Ni3(μ-OAc)2(L)2(OAc)2]·CHCl3 (2), and one tetranuclear Co(II) complex [Co4(L′)4(MeOH)4] (3) based on an unexpected ligand H2L′ derived from the cleavage of HL have been synthesized and characterized by elemental analyses, IR, UV–vis spectra, and single crystal X-ray diffraction analyses. The single crystals of complexes 1, 2 and 3 in the process of synthesis are obtained through different routes. The complex 1 includes two Cu(II) atoms, two completely deprotonated (L)− units and two μ-acetate ions, which displays a propeller-type motif. The complex 2 contains three Ni(II) atoms, two completely deprotonated (L)− units, two μ-acetate ions, two chelating acetate ions and one crystallizing chloroform molecule, the crystal structure of complex 2 reveals a butterfly-type motif. The complex 3 is made up of four Co(II) atoms, four completely deprotonated (L′)2− units (HL′: 2-[O-(1-hydroxyethyl)]oxime-6-methoxyphenol) and four coordinated methanol molecules, which shows a windmill-type motif. Besides, magnetic properties and Hirshfeld surface analyses were discussed.

C60H50Co2N9O15, triclinic, P1̅ (no. 2), a = 13.6074(19) Å, b = 13.9185(17) Å, c = 15.837(2) Å, α = 81.196(4)°, β = 86.607(4)°, γ = 81.665(4)°, Z = 2, V = 2930.7(7) Å3, Rgt(F) = 0.0564, wRref(F2) = 0.2010, T = 296(2) K.

Three novel N4-cavity Cu(II), Ni(II) and Zn(II) mononuclear complexes, [Cu(L)(NO3)2][Cu(L)(NO3)]NO3 (1) [Ni(L)(NO3)2] (2) and [Zn(L)(NO3)2] (3) were successfully synthesized via the reactions of a pyridine-containing N4-cavity bisoxime ligand L (L = 2,2'-[Ethylenedioxobis(azetidinyl)]pyridine) with Cu(II), Ni(II) and Zn(II) nitrates, respectively. Complexes 1-3 were characterized via elemental analysis, IR, UV-Vis spectra and X-ray crystallography. All three complexes are monoclinic systems, containing one M(II) atom and one (L) ligand moiety. Complexes 2 and 3 form centrosymmetric molecules. In addition, supramolecular interactions, Hirshfeld surface analysis were used to analyze the crystal properties that have been studied.

A new salamo-type fluorescence probe H2L was synthesized by a series of reactions and corroborated by single-crystal X-ray crystallography and 1H NMR spectra. Fluorescence of Co2+ selectively response showed “off” when cations were sequentially detected. The LOD of H2L to Co2+ was calculated to be 3.73 × 10-7 M in DMF/water (9:1, v/v) solution system. Meanwhile, the single crystal of the Co2+ complex with H2L was obtained by solvent evaporation. The structure of the complex [Co3(L)2(MeOH)2(μ-OAc)2]·2MeOH was validated by single-crystal X-ray diffraction, IR, and elemental analyses, and the mechanism of recognition of Co2+ by H2L was got. Density functional theory (DFT) and Hirshfeld surface analyses were investigated to further understand the experimental results observed.

Binuclear CoIII complex [Co2(L)3(DMF)3] containing a Schiff ligand H2L was synthesized and analyzed by elemental analysis, single crystal X-ray crystallography, FT-IR, UV–Vis absorption spectroscopy, Hirshfeld surface analysis and DFT calculation. The CoIII complex was a 3:2 ((L)2− : CoIII) binuclear structure. The spatial configuration of central CoIII ions was six-coordinated slightly twisted octahedron. The 3D supramolecular network structure was linked by intermolecular hydrogen bonds, C H···π and π···π stacking interactions. The Schiff ligand H2L exhibits weak luminescence, but this weak fluorescence is turned on after coordination with the ZnII ion. Furthermore, H2L could as an “OFF-ON” chemosensor for fluorescent recognition of ZnII.

Heterotrinuclear 3d-4f complexes with a naphthalenediol-based acyclic bis(salamo)-type ligand have been synthesized and structurally characterized. Spectral titrations clearly show that the heterotrinuclear complexes [Zn2(L)La(OAc)3] (1), [Zn2(L)Ce(OAc)3] (2) and [Zn2(L)Dy(OAc)3(CH3OH)]·CH2Cl2 (3) are acquired by the substitution reaction of the obtained homotrinuclear Zn(II) complex with 1 equiv. of Ln(NO3)3 (Ln3+=La3+, Ce3+ and Dy3+). Two Zn(II) ions are penta- and hexa-coordinated with geometries of distorted tetragonal pyramid and octahedron. La(III) ion is deca-coordinated, adopting a distorted bicapped square antiprism geometry. Ce(III) ion is nona-coordinated with geometry of distorted capped square antiprism as well as Dy(III) ion. The different coordination modes of acetate ions in complexes 1, 2 and 3 lead to different coordination numbers of the lanthanide(III) ions. Furthermore, the structures and fluorescence properties have been discussed.

Three trinuclear complexes constructed from a naphthalenediol-based bis(Salamo)-type tetraoxime ligand (H4L1), [Cu3(L1)(OAc)2]·CH3OH (1), [Zn3(L1)(OAc)2(CH3OH)2]·4CHCl3 (2), and [Cu2(L1)Na(NO3)(CH3OH)] (3), and one dinuclear complex, [{Cu(L2)}2] (4), based on an unexpected ligand H2L2 derived from the cleavage of H4L1 have been synthesized and characterized by X-ray diffraction analyses. Different anionic sources, transition metal salts, and rationally controlled reaction conditions play important roles in the construction of the resulting complexes with variable coordination geometries (coordination number ranges from 4 to 7), and four types of supramolecular network were controlled by noncovalent interactions, such as hydrogen bond, π···π stacking, C–H···π, Cu···π, and halogen-related interactions. The fluorescence properties of H4L1 and its complexes were investigated, and 2 exhibits unique bright cyan–yellow visible fluorescent emissions in different solvents.

C38H38Mn2N2O14, triclinic, P1̅ (no. 2), a = 8.2828(12) Å, b = 10.428(2) Å, c = 12.152(3) Å, α = 113.44(2)°, β = 93.369(16)°, γ = 107.890(16)°, Z = 1, V = 896.5(3) Å3, Rgt(F) = 0.0578, wRref(F2) = 0.1288, T = 293(2) K.

An unprecedented dinuclear CuII complex, [Cu2(L2)2], derived from a salamo-like chelating ligand H2L2, was produced by the cleavage of a newly synthesized, half-salamo-like ligand HL1 (2-[O-(1-ethyloxyamide)]oxime-3,5-dichloro-phenol). This was synthesized and characterized by elemental analyses, IR, UV&ndash, Vis and fluorescent spectra, single crystal X-ray diffraction analysis, and Hirshfeld surface analysis. X-ray crystallographic analysis indicated that the two CuII (Cu1 and Cu2) ions bore different (N2O3 and N2O2) coordination environments, the penta-coordinated Cu1 ion possessed a slightly twisted tetragonal pyramid geometry with the &tau, value &tau, = 0.004, and the tetra-coordinated Cu2 ion showed a slightly twisted square planar geometry. Interestingly, one oxime oxygen atom participated in the coordination reported previously. Moreover, an infinite two-dimensional layered supramolecular network was formed. Compared with HL1, the CuII complex possessed the characteristic of fluorescence quenching.

Two novel structurally characterized Co(II) metal-organic framework (Co(II) MOF) and Cd(II) coordination polymer (Cd(II) CP), [{Co(L)}2]n·nCH3COCH3 and [Cd(H2L)(CH3COO)2]n were self-assembled from a newly designed salamo-like ligand H2L bearing double terminal pyridine groups and Co(II) and Cd(II) ions, respectively. In the Co(II) MOF, the Co1 and Co2 ions are six-coordinated octahedron geometries, have similar coordination environments, and are located in the N2O2 cavities of the ligand (L)2− units, forming "Co1-L" and "Co2-L" parts, respectively. The terminal pyridine N atoms of the "Co1-L" (or "Co2-L") part are connected with "Co1-L" and "Co2-L" parts respectively, forming a metal-organic framework with double helix structure in thea-direction and regular channels in the c-direction. In the Cd(II) CP, Cd(II) ion is seven-coordinated single cap triangular prism geometry, did not participate in the coordination of the N2O2 cavity, but coordinated with free acetate in the solution. Two bidentate acetate anions chelate to Cd1 ion, and two Cd1 ions are bridged by O atom of one of the acetate anions to form Cd2(OAc)2 unit which was used as the junction point to connect with the terminal pyridine N atoms of H2L. Finally, the coordination polymer with large pore channels was formed. Spectroscopic analyses of H2L and its Co(II) MOF and Cd(II) CP are performed using IR, UV–Vis and fluorescence spectroscopy. TGA analyses show that the Co(II) MOF and Cd(II) CP have good stabilities. Various short-range interactions in the Co(II) MOF and Cd(II) CP are investigated through Hirshfeld surfaces analyses.

The Schiff base binuclear Zn(II) complexes, [Zn2(L)2∙(H2O)2]∙2DMF (1) and its coordination polymer [Zn2(L)2∙(4,4′-bpy)2]n (2) (H2L = 3-[(5-chloro-2-hydroxy-benzylidene)-amino]-4-hydroxy-chromen-2-one, 4,4′-bpy = 4,4′-bipyridine), were synthesized under the same experimental condition without or with the auxiliary ligand 4,4′-bpy, respectively. The structural analysis revealed that complexes 1 and 2 have different crystal structures. The complex 1 was a centrosymmetric binuclear structure. It is noteworthy that the linker 4,4′-bpy was introduced during the synthesis of complex 2, so that two water molecules in complex 1 were replaced by two 4,4′-bpy linkers to form one-dimensional (1D) chain-like coordination polymer. The central Zn(II) ions in complex 1 were penta-coordinated distorted square pyramid geometry with τ = 0.42. However, the Zn(II) ions of complex 2 were hexa-coordinated distorted octahedral geometry. The fluorescence spectrum showed the complex 2 containing 4,4′-bpy was substantially quenching of the fluorescence as compared with the complex 1. In addition, it could be seen from the DFT calculation the energy gaps of the complexes 1 and 2 were both reduced compared to the ligand H2L. However, the LUMO and HOMO orbits of the complex 2 were occupied by the 4,4′-bpy, which is different from complex 1, resulting in 1 and 2 had different spectral properties.

Two novel mono- and heptanuclear Ni(II) complexes, [Ni(HL1)2(EtOH)2]·2EtOH (1) and [Ni7(L2)3(μ3-OMe)2(μ3-OH)6(MeOH)6] (2), have been synthesized by the reaction of Ni(II) acetate with H2L1 and H2L2, respectively. In the Ni(II) complex 1, the ligand H2L1 was partially deprotonated, only NO donor atoms of one salicylidene moiety of the (HL1)− unit coordinate to Ni(II) atom. While all the three H2L2 ligands in the Ni(II) complex 2 were completely deprotonated. The seven Ni(II) atoms are all hexa-coordinated, and have two coordination environments. The fluorescence properties of the ligands, the Ni(II) complexes 1 and 2 have been discussed.

Using 3-MeOsalamo H2L (H2L = 1,2-bis(3-methoxysalicylideneaminooxy)ethane) with Zn(OAc)2·2H2O, Ln(NO3)3·6H2O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, and Tb), and 4,4′-bipy (4,4′-bipyridine) or H2bdc (terephthalic acid), three new families of heteromultinuclear ZnII–LnIII complexes: [{Zn(L)Ln(NO3)3(CH3OH)}2(4,4′-bipy)] (Ln = La (1·2CH3OH) and Ce (2)), [{Zn(L)Ln(NO3)3}2(4,4′-bipy)] (Ln = Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), and Tb(8)), [{(ZnL)2Ln}2(bdc)2]·(NO3)2·2CHCl3 (Ln = Ce (9), Pr (10) and Sm (11·2CH3CH2OH)), and 2∞[Zn(L)Ln(bdc)1.5] (Ln = Eu (12) and Gd (13·2CHCl3)) were obtained, respectively. Complexes 1–8 are heterotetranuclear dimers based on [Zn(L)Ln] moieties which are linked through the exo-dentate 4,4′-bipy having nitrogen-donor atoms. Heterohexanuclear complexes 9–11 constructed from almost linear trinuclear cationic [(ZnL)2Ln] moieties which are linked through the exo-dentate (bdc)2– bearing oxygen-donor atoms. Two 2D coordination polymers 12 and 13 are also assembled by [Zn(L)Ln] units with (bd...

C38H38Co2N2O14, monoclinic, P21/n (no. 14), a = 9.7459(5) Å, b = 7.9026(7) Å, c = 24.0622(15) Å, β = 100.260(5)°, Z = 2, V = 1823.6(2) Å3, Rgt(F) = 0.0576, wRref(F2) = 0.1201, T = 293(2) K.

C40H38CoN4O6, monoclinic, C2/c (no. 15), a = 25.848(2) Å, b = 9.7537(5) Å, c = 13.8302(11) Å, β = 93.760(7)°, Z = 4, V = 3479.3(4) Å3, R gt(F) = 0.0770, wR ref(F 2) = 0.1824, T = 293 K.

C38H34Ni2Cl2N4O12, monoclinic, C2/c (no. 15), a = 17.867(3) Å, b = 9.170(6) Å, c = 24.651(5) Å, β = 110.837(2)°, Z = 4, V = 3775(3) Å3, Rgt(F) = 0.0323, wRref(F2) = 0.1078, T = 293(2) K.

A rare homotrinuclear CuII salamo-based complex [Cu3(L)2(μ-OAc)2(H2O)2]·2CHCl3·5H2O was prepared through the reaction of a non-symmetric salamo-based ligand H2L and Cu(OAc)2·H2O, and validated by elemental analyses, UV-Visible absorption, fluorescence and infrared spectra, molecular simulation and single-crystal X-ray analysis techniques. It is shown that three CuII atoms and two wholly deprotonated ligand (L)2− moieties form together a trinuclear 3:2 (M:L) complex with two coordination water molecules and two bi-dentate briging μ-acetate groups (μ-OAc−). Besides, the Hirshfeld surface analysis of the CuII complex was investigated. Compared with other ligands, the fluorescent strength of the CuII complex was evidently lowered, showing that the CuII ions possess fluorescent quenching effect.

C52H42CuN4O4, monoclinic, I12/c1 (no. 15), a = 21.8573(13) Å, b = 5.8605(4) Å, c = 33.683(2) Å, β = 97.428(5)°, Z = 4, V = 4278.4(5) Å3, R gt(F) = 0.0554, wR ref(F 2) = 0.1255, T = 293(2) K.

C46H38MnN3O8, triclinic P1̅ (no. 2), a = 8.9705(6) Å, b = 12.0309(8) Å, c = 18.4209(13) Å, α = 96.303(2)°, β = 103.884(2)°, γ = 101.636(2)°, Z = 2, V = 1864.0(2) Å3, R gt(F) = 0.0496, wR ref(F 2) = 0.1274, T = 296 K.

C26H22N2O4, triclinic P1̅, a = 8.035(3) Å, b = 10.387(4) Å, c = 13.126(5) Å, α = 83.831(10)°, β = 78.214(10)°, γ = 81.470(10)°, Z = 2, V = 1101.78(19) Å3, R gt(F) = 0.0663, wR ref(F 2) = 0.1830, T = 296(2) K.

Three polyhydroxyl-bridged tetranuclear MnIII complexes [Mn4(L1a)2(&mu, 3-OMe)2(&mu, 2-OMe)2(MeOH)2] (1), [Mn4(L2a)2(&mu, 2-OMe)2(H2O)2] (2), and [Mn4(L3a)2(&mu, 2-OMe)2(H2O)2] (3) derived from Mnn+-promoted reactivity of Schiff base ligands (HL1 = 1-(4-{[(E)-3,5-dichlorine-2-hydroxybenzylidene]amino}phenyl)ethanone O-benzyloxime, HL2 = 1-(4-{[(E)-3-bromine-5-chloro-2-hydroxybenzylidene]amino}phenyl) ethanone O-benzyloxime, and HL3 = 1-(4-{[(E)-3,5-dibromine-2-hydroxybenzylidene]amino}phenyl)ethanone O-benzyloxime) have been synthesized and characterized. In the MnIII complexes 1, 2, and 3, the newly formed ligands (L1a)4&minus, (L2a)4&minus, and (L3a)4&minus, are derived from the chemoselective cleavage of the C=N bond in the original Schiff base ligands HL1, HL2, and HL3 to form corresponding halogenated salicylaldehyde, 3,5-dichlorosalicylaldehyde, 3-bromine-5-chlorosalicylaldehyde, and 3,5-dibrominesalicylaldehyde, respectively. Then, the further addition of acetone to two halogenated salicylaldehyde molecules in situ &alpha, &alpha, double aldol reaction promoted by Mnn+ ions in the presence of base to give the new ligands ((Lna)4&minus, X-ray crystallographic analyses of the MnIII complexes 1, 2, and 3 show that the three complexes are all tetranuclear structure and crystallizes in the triclinic system, space group P-1. The four MnIII ions and bridging alkoxido groups are arranged in a face-shared dicubane-like core with two missing vertices. In the three MnIII complexes, the asymmetric unit contains two kinds of different MnIII ions (Mn1 and Mn2), where the MnIII ions are all hexacoordinated with slightly distorted octahedral geometries. Simultaneously in the synthesis of multinuclear Mnn+ complexes above, we explored the crystal structure, spatial configuration, and spectroscopic properties of the multinuclear MnIII complexes with different halogen substituents.

Solvent-induced trinuclear NiII complexes, [{Ni(L)(MeOH)}2(OAc)2Ni]·2MeOH (1), [{Ni(L)(EtOH)}2(OAc)2Ni]·2H2O (2), [{Ni(L)(n-PrOH)}2(OAc)2Ni]·2H2O (3) and [{Ni(L)(i-PrOH)}2(OAc)2Ni] (4), have been prepared with an unsymmetric Salamo-like ligand H2L, and characterized via X-ray crystallography, FT-IR, UV-Vis and fluorescence spectra. In complexes 1, 2, 3 and 4, there are two ligand (L)2− moieties, two acetato ligands, two coordinated methanol, ethanol, n-propanol or i-propanol molecules, respectively, as well as other crystallizing solvent molecules. Two acetato ligands coordinated to the three NiII ions via usual Ni-O-C-O-Ni bridges, and four µ-phenoxo oxygen atoms coming from two [NiL(solvent)] units coordinate to the central NiII ions. Although different solvents are induced in the complexes, all the NiII ions are six-coordinated and adopt geometries of distorted octahedron. Magnetic measurements were performed on complex 2, an intramolecular antiferromagnetic interaction was observed between NiII ions and a simulation of the experimental data gives J = −2.96 cm−1 and g = 2.30.

A new Cu(II) complex with asymmetric Salamo-type ligand (H2L, 4-bromo-6′-ethoxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) has been synthesized and characterized structurally. The X-ray crystal structure of the Cu(II) complex shows it to be a binuclear complex, in which each Cu(II) atom is in a distorted square-pyramidal geometry. The Cu(II) complex crystallizes in the monoclinic system, space group P21/c, with unit cell parameters a = 14.7109(1), b = 8.6254(7), c = 30.124(3) A, β = 100.7400(1), and Z = 4. The Cu(II) complex consists of two Cu(II) atoms, and two L2– units, and each Cu(II) complex molecule links four other molecules into an infinite 2D-layer supramolecular structure. Meanwhile, the Cu(II) complex exhibits emission with the maximum emission wavelength λmax = 443 nm when excited at λex = 340 nm.

Two new Co(II) complexes, [{Co(L)}2{Co(Pic)2(CH3OH)2}] (1) and [{CoL(μ-OAc)}2Co] (2), where H2L = 2,2′-[Ethylenedioxybis(nitrilomethylidyne)]dinaphthol, were designed, synthesized and characterized by elemental analysis, FT-IR spectra, UV-Vis spectra, and X-ray crystallography. Complex 1 consists of two [CoL] and one [Co(Pic)2(CH3OH)2] (Pic = picrate) units and in the [CoL] unit, the Co(II) atom is tetra-coordinated with a slightly distorted square-planar geometry. In the [Co(Pic)2(CH3OH)2] unit, the Co(II) atom is hexa-coordinated with a slightly distorted octahedral geometry. Meanwhile in complex 2, two acetate ions coordinate to three Co(II) atoms through Co-O-C-O-Co bridges and four μ-naphthoxo oxygen atoms from two [CoL] units also coordinated to the central Co(II) atom. Thus, complex 2 has two distorted square pyramidal coordination geometries around the terminal Co(II) atom and an octahedral geometry around the central Co(II) atom. The supramolecular structures of complex 1 is a 3D-network supramolecular structure linked by C-H···O hydrogen bonds and π···π stacking interaction, but complex 2 possesses a self-assembled 2D-layer supramolecular structure linked by C-H···π and π···π stacking interactions. The structure determinations show that the coordination anions are important factors influencing the crystalline array.

A new heteronuclear Ln-Co carbonyl cluster, Ce4Yb2(μ3-L)4(CF3COO)8(DMF)6Co (L=(CO)6Co2CC(COO)2-), has been synthesized by reaction of (CO)6Co2CC(COOH)2 with Ce (OOCCF3)32H2O and Yb (OOCCF3)32H2O. The cluster structure was characterized by single-crystal X-ray diffraction and IR. The crystal is monoclinic crystal system and C2/c space group. X-ray analysis revealed that the heterometallic cluster belonged to a rare class of Ln-Co carbonyl cluster bridged by carboxylate groups of carbonyl cluster ligands. The cluster was monometric unit and exhibited cage-like configuration.

A new naphthalenediol-based bis(salamo)-type fluorescent probe H4L for Zn2+ and CN- was reported. Probe H4L showed a highly selective fluorescence enhancement toward Zn2+ over other metal ions including Cd2+, and obtained the L-Zn2+complex can only detect CN- in various anions. Their recognition mechanisms were explained by Job plots, fluorescent and UV-vis titrations, and theoretical calculations. The L-Zn2+complex has been synthesized and structurally characterized using Hirshfeld surface analysis, elemental analyses, IR, UV-Vis and fluorescent spectra. Additionally, the relay probe with the wide adaptability of pH range and excellent stability showed highly selectivity for CN- recognition.

[Zn4(L1)2(OAc)2(CH3CH2OH)2] and [CuL2(H2O)] with new asymmetric Salamo-type ligands have been synthesized and characterized. There are two coordination geometries (trigonal bipyramidal and square pyramidal) in the Zn(ΙΙ) complex, and the Cu(II) complex has square-pyramidal geometry. A self-assembling continual zigzag chain is formed by intermolecular hydrogen bonds in the Cu(II) complex. The self-assembling array of the Zn(II) complex is linked by intermolecular C–H⋯O and C–H⋯π interactions. Blue emissions of the Zn(II) and Cu(II) complexes in DMF solution are exhibited by fluorescence.

The complex characteristics of p-sulfonated calix[n]arene (SCnA) and two tryptophans N-[(tert-butoxy) carbonyl]-tryptophan (trp-A) and N-carbobenzoxy-tryptophane (trp-B) were examined through various techniques. Spectrofluorimetry was performed at different temperatures to determine the stability constants and evaluate the thermodynamic parameters of the two complexes. The effect of pH on complex formation was estimated. According to the fluorescence data, the assumption about the steric hindrance of the tert-butyl group of trp-A and the phenyl group of trp-B was put forward. (1)H NMR was also performed to determine the binding interaction mechanism. Results showed that the indole benzene rings of the two tryptophans partly penetrated into the cavity of p-sulfonated calix[n]arene. The shift in Ha, Hb and Hc, Hd positions became more significant as the number of phenolic units of the calixarene ring increased. Molecular modeling of the complexes elucidated the assumption about the steric hindrance of the tert-butyl group of trp-A and the phenyl group of trp-B. These observations of molecular modeling computation are consistent with previous fluorescence data and (1)H NMR results.

A new mononuclear CdII complex, [CdL(H2O)2], with halogen-substituted Salen-type bisoxime ligand (H2L = 4,4′-dibromo- 6,6′-dichloro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol), was synthesized and structurally characterized. The CdII complex crystallizes in the monoclinic system, space group C2/c. The CdII center exhibits a slightly distorted octahedral geometry with halogen-substituted Salen-type bisoxime ligand forming the basal N2O2 coordination plane and two oxygen atoms from the coordinated water molecules in the axial position. An infinite 1D metal-water chain is formed by intermolecular hydrogen-bonding and π-π stacking interactions of neighboring benzene rings. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

A new trinuclear Ni(II) complex {[NiL(DMF)]2(OAc)2Ni}·2DMF (H2L = 4,4′-dichloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol) is synthesized and characterized by elemental analyses, IR spectra, UV-Vis spectra and X-ray crystallography. The results show that the Ni(II) complex consists of three Ni(II) ions, two tetradentate (μ-L)2− units, two coordinated μ-acetate ions, two coordinated DMF molecules, and two crystallization DMF molecules. All hexacoordinated Ni(II) ions of the complex have a slightly distorted octahedral geometry. The crystal packing of the Ni(II) complex reveals a notable feature of this structure: the formation of an infinite supramolecular 2D layered structure by virtue of intermolecular C-H…O hydrogen bonding.

A supramolecular CoII complex, [CoL(H2O)2], bearing Salen-type bisoxime chelate ligand 4,4′,6,6′-tetrachloro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L), has been synthesized and structurally characterized by elemental analyses, IR spectra, UV–vis spectra, and X-ray diffraction techniques. The crystal structure of [CoL(H2O)2] indicates that the CoII complex consists of one CoII atom, one L2– unit, and two coordinated water molecules. The CoII complex exhibits slightly distorted octahedral geometry with the Salen-type bisoxime ligand forming the basal N2O2 coordination plane and two oxygen atoms from the coordinated water molecules in the axial positions. An infinite 1D metal–water chain and 2D supramolecular network structure were formed by intermolecular O-H···O, O-H···Cl, and C-H···O hydrogen bonding and π-π stacking interactions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Met...

The supramolecular interaction between cucurbit[7]uril (CB[7]) as the host and the anti-cancer drug methotrexate (MTX) as the guest was studied using fluorescence spectroscopy, UV-visible absorption spectroscopy, 1H NMR, 2D NOESY, and theoretical calculations. The experimental results confirmed the formation of 1:2 inclusion complex with CB[7] and indicated a simple and sensitive competitive method for the fluorescence detection of MTX. It was found that the fluorescence intensities of CB[7]-palmatine, CB[7]-berberine and CB[7]-coptisine were quenched linearly upon the addition of MTX. The linear ranges obtained in the detection of MTX were 0.1-15μgmL-1, 0.2-15μgmL-1, and 0.4-15μgmL-1 with detection limits of 0.03μgmL-1, 0.06μgmL-1, and 0.13μgmL-1, respectively. This method can be used for the determination of MTX in biological fluids. These results suggested that cucurbit[7]uril is a promising drug carrier for targeted MTX delivery and monitoring, with improved efficacy and reduced toxicity in normal tissues.

A supramolecular CuII complex, [Cu(L)(H2O)] (H2L: 4,4′,6,6′-tetrachloro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol), has been synthesized and structurally characterized. X-ray crystallographic analysis shows that the complex is a centrosymmetric mononuclear CuII complex, and the CuII atom is penta-coordinated by two phenolic O atoms and two oxime N atoms from the deprotonated Salen-type ligand, and one oxygen atom from the coordinated water molecule. A self-assembling continual supramolecular structure is formed by intermolecular O3-H3···O2 and O3-H3···Cl1 hydrogen bonds.

The tri-nuclear cobalt(II) complex, [(CoL)2(μ-OAc)2Co]·2CHCl3 (H2L = 5,5'-dimethoxy-2,2'-[(ethylene)dioxybis(nitrilome thylidyne)]diphenol), has been synthesised. Its X-ray structure shows it to contain two acetate ions coordinating to the three cobalt(II) atoms through Co–O–C–O–Co bridges, and four μ-phenoxo-oxygen atoms from two [CoL] chelates also coordinating to the central cobalt(II) atom. The complex possesses two penta- and one hexa-coordinated cobalt atoms. The crystal packing of the CoII complex shows that a 2D-layer supramolecular network parallel to the ab-plane is formed through intermolecular C–H···O and C–H···Cl hydrogen bonding interactions.

Two nickel(II) complexes, namely {[NiL(MeOH)(μ-OAc)]2Ni}·2CH2Cl2·2MeOH (1) and {[NiL(EtOH)(μ-OAc)]2Ni}·2EtOH (2) {H2L = 5, 5′-dimethoxy-2, 2′-[(ethylene)dioxybis(nitrilomethylidyne)]diphenol}, were synthesized and structurally characterized. Two trinuclear NiII complexes are both hexacoordinate around the central NiII atoms, showing octahedral coordination arrangements, and each complex comprises three divalent NiII atoms, two deprotonated L2– ligands, in which four μ-phenoxo oxygen atoms forming two [NiL(X)] (X = MeOH or EtOH) units, and coordinated and non-coordinated solvent molecules. Complex 1 exhibits a 2D supramolecular network through intermolecular O–H···O, C–H···O and C–H···π interactions, whereas complex 2 forms an infinite 1D chain by intermolecular C–H···O hydrogen bonding interactions.

Salen-type bisoxime 5,5′-dimethoxy-2,2′-[(ethylenedioxy)bis(nitrilomethylidyne)]diphenol (H2L) and its trinuclear Ni(II) cluster {[(NiL)(n-BuOH)]2(μ-OAc)2Ni} · n-BuOH have been synthesized and structurally characterized. The structure of H2L adopts an L-shape conformation where the two salicylaldoxime moieties are well separated. In the trinuclear Ni(II) cluster, two acetates coordinate to three Ni(II)'s through Ni–O–C–O–Ni bridges, four μ-phenoxos from two [NiL(n-BuOH)] units also coordinate to Ni(II), and two n-butanols coordinate to two terminal Ni(II)'s forming a distorted octahedral geometry. The Ni–O–C–O–Ni and μ-phenoxo bridges play important roles in assembling Ni(II) and the ligands. H2L forms a rectangle-like large cave structure through O–H ··· N, C–H ··· O, and C–H ··· π hydrogen-bond interactions, whereas its trinuclear Ni(II) cluster exhibits a 3-D supramolecular network structure through intermolecular O–H ··· O, C–H ··· O, and C–H ··· π hydrogen-bond interactions.

A new Salen-type bisoxime chelating ligand, 3,3′-dimethoxy-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol (H2L), and its Ni(II) cluster, [{NiL(CH3CH2OH)}2(OAc)2Ni]·2CH3CH2 OH·CH3COCH3, have been synthesized and characterized by elemental analyses, FT-IR spectra, UV-vis spectra, 1H-NMR, molar conductance measurements, and thermal properties. X-ray crystallographic analyses reveal that the structure of the Ni(II) cluster is as follows: two acetate groups coordinating to three metal(II) ions through Ni–O–C–O–Ni bridges and four μ-phenoxo oxygen atoms from two [NiL(CH3CH2OH)] units also coordinating to metal(II) ions. In the cluster, two ethanol molecules coordinate to the two terminal nickel(II) ions and form a trinuclear structure. Meanwhile, the Ni–O–C–O–Ni and μ-phenoxo bridges play important roles in assembling metal ions and ligands.

An unexpected dinuclear Cu(II) complex, [Cu2(L2)2] (H2L2 = 3-methoxysalicylaldehyde O-(2-hydroxyethyl)oxime), has been synthesized via complexation of Cu(II) acetate monohydrate with H4L1. Catalysis by Cu(II) results in unexpected cleavage of two N–O bonds in H4L1, giving a dialkoxo-bridged dinuclear Cu(II) complex possessing a Cu–O–Cu–O four-membered ring core instead of the usual bis(salen)-type tetraoxime Cu3–N4O4 complex. Every complex links six other molecules into an infinite-layered supramolecular structure via 12 intermolecular C–H ··· O hydrogen bonds. Furthermore, Cu(II) complex exhibits purple emission with maximum emission wavelength λmax = 417 nm when excited with 312 nm.

An unprecedented dinuclear copper(II) complex, [Cu2(L2)2] (H2L2 = 3-Methoxysalicylaldehyde O-(2-hydroxyethyl)oxime), has been synthesized via the complexation of copper(II) acetate monohydrate with unsymmetrical Salen-type ligand H2L1 (H2L1 = 3-Methoxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol). The crystal structure of the copper(II) complex has been determined by single-crystal X-ray diffraction method. The catalysis of copper(II) ions results in the unexpected cleavage of one of the N˭O bonds in the ligand H2L1, giving a novel dialkoxo-bridged dinuclear copper(II) complex possessing a Cu˭O˭Cu˭O four-membered ring core instead of the usually desired Salen-type bisoxime Cu˭N2O2 mononuclear complex.

A tetranuclear Zn(ΙΙ) complex, [Zn4L2(OAc)2(CH3OH)2] with an unsymmetric Salen-type bisoxime (H3L = 6-hydroxy-4′,6′-dibromo-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol), has been synthesized and structurally characterized. There are two kinds of coordination geometry (trigonal bipyramidal and square pyramidal) in the Zn(ΙΙ) complex. The molecule has serious distortion probably from the asymmetry. The complex exhibits blue emission with the maximum emission wavelength λ max = 423 nm when excited with 340 nm.

Two solvent-induced complexes, [CoL2(CH3OH)2] (1) and [CoL2(CH3CH2OH)2] (2), have been synthesized by the reaction of an oxime-type ligand (HL, 4-[(Ethoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one) with cobalt(II) acetate tetrahydrate in different solvents. X-ray crystallographic analyses have indicated that complexes 1 and 2 have a similar structure, consisting of one CoII atom, two L− units, and two coordinated methanol or ethanol molecules. Interestingly, two CoII atoms in the structures of complexes 1 and 2 are all six-coordinated, approaching a staved octahedral geometry, but complexes 1 and 2 are grown up in methanol/chloroform and ethanol, respectively. Right because of this, solvent effect cause to the difference of the crystal structures: complex 1 forms an infinite supramolecular chain by intermolecular hydrogen bonds, while complex 2 exhibits three-dimensional supramolecular networks through intermolecular hydrogen bonds and C-H···π interactions.

Two new Cu(II) complexes, [Cu(L1)2] (1) and [Cu(L2)2] (2) (HL1 = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-methyl oxime; HL2 = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-ethyl oxime), have been synthesized and characterized by physicochemical and spectroscopic methods. X-ray crystallographic analyses show that complexes 1 and 2 have similar structures, consisting of one Cu(II) atom and two L− units. In both complexes, the Cu(II) atom, lying on an inversion center, is four-coordinated in a trans-CuN2O2 square-planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate oxime ligands. Moreover, both complexes form an infinite three-dimensional supramolecular structure involving intermolecular C–H···Br hydrogen bonds and π···π stacking interactions between the metal chelate rings and aromatic rings. Substituent effects in the two complexes are discussed.

A dinuclear Cu(II) complex, [Cu2(L2)2] (H2L2 = 4-methoxysalicylaldehyde O-(2-hydroxyethyl)- oxime), has been synthesized through the complexation of Cu(II) acetate monohydrate with the ligand H2L1 (H2L1 = 5,5´ -dimethoxy-2,2´-[(ethylene)dioxybis(nitrilomethylidyne)]diphenol), and characterized by elemental analyses, IR, UV/Vis and emission spectra. The crystal structure of the Cu(II) complex has been determined by single-crystal X-ray diffraction. The catalysis by Cu(II) ions results in the unexpected cleavage of the N-O bonds in the ligand H2L1, giving a novel dialkoxo-bridged dinuclear Cu(II) complex possessing a Cu-O-Cu-O four-membered ring core instead of the expected salen-type bisoxime Cu-N2O2 complex

A new dinuclear CuII complex, [Cu2(3-MeOSalamo-2)(H2O)3]·2pic·CH3COCH3·H2O, has been synthesized by the reaction of copper(II) picrate tetrahydrate with H2(3-MeOSalamo-n) (n = 2). X-ray crystallographic analysis reveals that the complex is a dinuclear structure when the O-alkyl chain length is relatively short (two CH2 groups), while a tetranuclear structure is obtained when the O-alkyl chain length becomes longer (four CH2 groups). In the complex, the μ-phenoxo bridging, picratol, and intermolecular hydrogen bonds play important roles in assembling CuII ions and ligands. Interestingly, the complex not only has a helical chain, but has an infinite metal–water chain supramolecular structure.

A new Co(II) cluster, {[CoL(DMF)]2(OAc)2Co}·2DMF (H2L = 4,4′-dichloro-2,2′-[(1,3-propylene)dioxybis (nitrilomethylidyne)]diphenol), has been synthesized and characterized by elemental analysis, IR spectrum, UV–Vis spectrum, and X-ray diffraction method. The results indicate that the Co(II) cluster consists of three Co(II) ions, two tetradentate (μ-L) 2− units, two coordinated μ-acetate ions, two coordinated DMF, and two crystallizing DMF molecules. All the hexa-coordinated Co(II) ions of the Co(II) cluster have a slightly distorted octahedral geometry. The crystal packing of the Co(II) cluster shows that a notable feature of this structure resides in the formation of a novel 2D supramolecular structure through intermolecular C‒H···O interaction and weak intramolecular C‒H···(Ph) interaction along the b-axes.

Three mononuclear Schiff base copper(II) complexes, [Cu(L1)2] (1), [Cu(L2)2] (2) and [Cu(L3)2] (3) (HL1= 2,4-dichloro-6-[(2-chloro-3-pyridyl)iminomethyl]phenol, HL2 = 2,4-dibromo-6-[(2-chloro-3-pyridyl)-iminomethyl]phenol, HL3 = 2-bromo-4-chloro-6-[(2-chloro-3-pyridyl)iminomethyl]phenol), have been synthesized and characterized by elemental analyses, IR, UV–Vis spectra, and X-ray single crystal diffraction. X-ray structures reveal each crystal unit contains two molecules and the coordination environment around the copper(II) atom is tetracoordinated by two Schiff base ligands, showing a tetrahedron geometry with some distortion. Pairs of intermolecular C–H···X (X = Cl or Br), C–H···N and C–H···O hydrogen bonds form many hydrogen bonding rings and play a crucial role in stabilizing the crystal structures.

Two new complexes, [Cu(L1)2] (1) and [Cu(L2)2(H2O)]·CH3OH (2), have been synthesized via the complexation of copper(II) acetate monohydrate with two mono-oxime chelating ligands (HL1: 4-[(Methoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H- pyrazol-3(2H)-one and HL2: 4-[(Ethoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one), respectively. X-ray crystal structure determination of the two complexes show that complex 1 consists of one copper(II) ion, two bidentate (L1)− units, and the copper atom of complex 1 has a square planar geometry distorted tetrahedrally with four-coordination, while complex 2 consists of one copper(II) ion, two bidentate (L2)− units, one coordinated H2O, and one crystallizing methanol molecule, as expected from the analytical data. And the copper atom of complex 2 has a slightly distorted tetragonal pyramid geometry with five-coordination. Complex 2 is a self-assembling infinite chain supramolecular structure formed by intermolecular hydrogen bonds. Meanwhile, the photoph...