Structural characterization of a new samarium-sodium heterometallic coordination polymer

Lanthanide-containing materials are of inter-est in the field of crystal engin-eering because of their unique properties and distinct structure types. In this context, a new samarium-sodium heterometallic coordination polymer, poly[tetra-kis-(μ2-2-formyl-6-meth-oxy-phenolato)samarium(III)sodium(I)], {[SmNa(C8H7O3)4]·solvent}n (Sm-1), was synthesized and crystallized via slow evaporation from a mixture of ethanol and aceto-nitrile. The compound features alternating SmIII and NaI ions, which are linked by ortho-vanillin (o-vanillin) ligands to form a mono-periodic chain-like coordination polymer. The chains propagate along the [001] direction. Residual electron density of disordered solvent mol-ecules in the void space could not be reasonably modeled, thus the SQUEEZE function was applied. The structural, vibrational, and optical properties are reported.

Synthesis, Crystal Structures and Magnetic Properties of Trinuclear {Ni2Ln} (LnIII = Dy, Ho) and {Ni2Y} Complexes with Schiff Base Ligands

The reaction of the Schiff base ligand o-OH-C6H4-CH=N-C(CH2OH)3, H4L, with Ni(O2CMe)2∙4H2O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes [Ni2Ln(H3L)4(O2CMe)2](NO3) (Ln = Dy (1), Ho (2), and Y (3)) which crystallize in the non-centrosymmetric space group Pna21. The complex cation consists of the three metal ions in an almost linear arrangement. The {Ni2Ln} moieties are bridged through two deprotonated Ophenolato groups from two different ligands. Each terminal NiII ion is bound to two ligands through their Ophenolato, the Nimino atoms and one of the protonated Oalkoxo groups in a distorted octahedral. The central lanthanide ion is coordinated to four Ophenolato oxygen from the four ligands, and four Ocarboxylato atoms from two acetates which are bound in the bidentate chelate mode, and the coordination polyhedron is biaugmented trigonal prism, which probably results in a non-centrosymmetric arrangement of the complexes in the lattice. The magnetic properties of 1–3 were studied and showed that 1 exhibits field induced slow magnetic relaxation.

Anion-Dependent Structure and Luminescence Diversity in ZnII-LnIII Heterometallic Architectures Supported by a Salicylamide-Imine Ligand

To advance the structural development and fully explore the application potential, it is highly desirable but challenging to elucidate the relationship between the structures and properties of Zn^II-Ln^III heterometallic species. Herein, three types of Zn^II-Ln^III heterometallic compounds (Ln^III = Gd^III, Tb^III) formulated as [Zn₁₆Ln₄L₁₂(μ₃-O)₄(NO₃)₁₂]·8CH₃CN (ZnLn-1), [Zn₂Ln₂L₂(NO₃)₆(H₂O)₂]·3CH₃CN (ZnLn-2), and [Zn₄Ln₂L₈(OAc)₁₂]·xCH₃CN (ZnLn-3: for Ln = Gd, x = 5; for Ln = Tb, x = 4) were dictated by common inorganic anions, NO₃^- and OAc^-, with the aid of the multidentate ligand H₂L with propane as the central skeleton and 3-methoxysalicylamide and 3-methoxysalicylaldimine as terminal groups. ZnLn-1 features cubic cages with four {Zn₄L₃} tetrahedral subunits and four Ln³⁺ centers positioned at the eight vertices alternately when NO₃^- was introduced into the reaction system exclusively. An attempt to replace NO₃^- in ZnLn-1 with OAc^- partially led to the formation of {Zn₂Ln₂L₂} heterometallic wheels. Meanwhile, ZnLn-3 featuring double-hairpin-like {Zn₄Ln₂L₄} hemicycles that are orthogonal to each other assisted by intermolecular hydrogen bonds was constructed when NO₃^- in ZnLn-1 was completely replaced by OAc^-. Their structural integrity in solution were ascertained by both emission and ¹H NMR spectroscopy. Ascribed to the different Zn²⁺-containing antenna, ZnTb-2 possesses a relatively strong emission characteristic of Tb³⁺; ZnTb-1 has moderate Tb³⁺ luminescence, yet an absence of Tb³⁺ emission is found in ZnTb-3. Such an emission difference could be mainly attributed to the antenna effect directed by distinct structural characteristics induced by anions. The anion-dictated self-assembly strategy presented herein not only offers a facile approach to regulate the coordination mode of H₂L to such an extent to obtain diverse structures of Zn^II-Ln^III heterometallic species but also provides an understanding of how common inorganic anions tune coordination-driven self-assemblies as well as the subsequent luminescence properties.

Tuning the coordination behavior of an unexplored asymmetric multidentate ligand for developing diverse heterometallic architectures with luminescent and magnetic properties

Three types of heterometallic species including metal clusters and a metal macrocycle have been developed by tuning the coordination behavior of a new asymmetric ligand with metal cations and anions.

Unprecedented Dinuclear CuII N,O-Donor Complex: Synthesis, Structural Characterization, Fluorescence Property, and Hirshfeld Analysis

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–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 τ value τ = 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.

Fluorescence Properties and Density Functional Theory Calculation of a Structurally Characterized Heterotetranuclear [ZnII2–SmIII2] 4,4′-Bipy-Salamo-Constructed Complex

A new heterotetranuclear complex, [{Zn(L)Sm(NO3)3}2(4,4′-bipy)]·2CH3OH, was synthesized via an unsymmetrical single salamo-like ligand H2L: 6-methoxy-6′-ethoxy-2,2′-[ethylenedioxybis(azinomethyl)]diphenol, with Zn(OAc)2·2H2O, Sm(NO3)3·6H2O, and 4,4′-bipyridine by the one-pot method. The [ZnII2–SmIII2] complex was validated via elemental analysis, powder X-ray diffraction (PXRD) analysis, infrared spectroscopy, and ultraviolet–visible (UV–Vis) absorption spectroscopy. The X-ray single crystal diffraction analysis of the [ZnII2–SmIII2] complex was carried out via X-ray single-crystal crystallography. The crystal structure and supramolecular features were discussed. In addition, while studying the fluorescence properties of the [ZnII2–SmIII2] complex, the density functional theory (DFT) calculation of its structure was also performed.

A Newly Synthesized Heterobimetallic NiII-GdIII Salamo-BDC-Based Coordination Polymer: Structural Characterization, DFT Calculation, Fluorescent and Antibacterial Properties

A unprecedented hetero-bimetallic 3d-4f BDC-salamo-based coordination polymer, [(L)Ni(BDC)Gd(NO3)(DMF)] was prepared and validated via elemental analyses, IR and UV–Visible absorption spectra, DFT calculation, and X-ray crystallography. The six-coordinated Ni1 ion lies at the N2O2 donor site of the L2− moiety, and one DMF O atom and carboxylate O atom occupy, collectively, the axial positions, and form a twisted octahedron. The nine-coordinated Gd1 ion consists of three oxygen atoms (O12, O13, and O14) of two carboxylate groups, two oxygen atoms (O8 and O9) derived from one bidentate nitrate group, and an O2O2 coordination site (O1, O2, O6, and O5) of the L2− unit, forming a twisted three-capped triangular prism coordination geometry. Compared to the ligand (H2L), the fluorescence intensity decreases due to the coordination of metal ions. Meanwhile, the antibacterial activities are researched.

An Unexpected Trinuclear Cobalt(II) Complex Based on a Half-Salamo-Like Ligand: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, Antimicrobial and Fluorescent Properties

An unexpected trinuclear Co(II) complex, [Co3(L2)2(μ-OAc)2(CH3OH)2]·2CH3OH (H2L2 = 4,4′-dibromo-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) constructed from a half-Salamo-based ligand (HL1 = 2-[O-(1-ethyloxyamide)]oxime-4-bromophenol) and Co(OAc)2·4H2O, has been synthesized and characterized by elemental analyses, infrared spectra (IR), UV-Vis spectra, X-ray crystallography and Hirshfeld surface analysis. The Co(II) complex contains three Co(II) atoms, two completely deprotonated (L2)2− units, two bridged acetate molecules, two coordinated methanol molecules and two crystalline methanol molecules, and finally, a three-dimensional supramolecular structure with infinite extension was formed. Interestingly, during the formation of the Co(II) complex, the ligand changed from half-Salamo-like to a symmetrical single Salamo-like ligand due to the bonding interactions of the molecules. In addition, the antimicrobial activities of HL1 and its Co(II) complex were also investigated.

A New Half-Salamo-Based Homo-Trinuclear Nickel(II) Complex: Crystal Structure, Hirshfeld Surface Analysis, and Fluorescence Properties

A new homo-trinuclear Ni(II) half-salamo-based complex [Ni3(L)2(μ-OAc)2(OAc)2(CH3OH)2]·2CH3OH was synthesized via the reaction of a tridentate ligand HL (2-[O-(1-ethyloxyamide)]oxime-4-bromophenol) and Ni(OAc)2·4H2O, and characterized using elemental analyses, IR spectra, UV-Vis absorption spectra, X-ray crystallography, and Hirshfeld analysis. Interestingly, single-crystal X-ray analysis showed that the two acetate molecules were bonded simultaneously with the Ni(II) atoms by mono-dentate chelating and bidentate bridging coordination modes, respectively, and the resulting hexa-coordinate geometries were ultimately formed. Furthermore, the Hirshfeld analysis of the complex was studied. Compared with HL, the complex fluorescence intensity was significantly lowered, indicating that the Ni(II) ions have fluorescence quenching characteristics.

A cationic tetrahedral Zn(ii) cluster based on a new salicylamide imine multidentate ligand: synthesis, structure and fluorescence sensing study

We present here a monocationic Zn^II tetrahedral cluster which is extremely stable and exhibits highly sensitive and selective recognition of phosphates against other common anions in water containing media.

Synthesis and Fluorescence Properties of a Structurally Characterized Hetero-Hexanuclear Zn(II)-La(III) Salamo-Like Coordination Compound Containing Auxiliary Ligands

A hetero-hexanuclear Zn(II)-La(III) coordination compound, [{(ZnL)2La}2(bdc)2](NO3)2 (H2bdc = terephthalic acid) has been synthesized with a symmetric Salamo-like bisoxime, and characterized by elemental analyses, IR, UV-Vis, fluorescent spectroscopy, and single-crystal X-ray diffraction analysis. All of the Zn(II) ions are pentacoordinated by N2O2 donator atoms from the (L)2− unit and one oxygen atom from one terephthalate anion. The Zn(II) ions adopt trigonal bipyramidal geometries (τZn1 = 0.61, τZn2 = 0.56). The La(III) ions are decacoordinated in the Zn(II)-La(III) coordination compound and has a distorted bicapped square antiprism geometry. Meanwhile, the photophysical property of the Zn(II)-La(III) coordination compound was also measured and discussed.

A heterotrimetallic Ni(II)–Dy(III) bis(salamo)-based complex: synthesis, structure and fluorescent property

A discrete heterotrinuclear complex [{Ni2LDy(OAc)3(CH3OH)}2] · 2CH3OH · 3CH2Cl2, with a naphthalenediol-based acyclic bis(salamo) ligand H4L, has been synthesized and structurally characterized using elemental analyses, IR, UV/Vis and fluorescence spectra and single crystal X-ray diffraction. The crystal structure shows two crystallographically independent but chemically identical molecules (moleculesIandII). All the Ni(II) atoms are hexa-coordinated with slightly distorted octahedral geometries. The central Dy atoms are nona-coordinated with slightly distorted tricapped trigonal prism geometries. An infinite 3D supramolecular structure is formed via intermolecular hydrogen bonding and C–H…π interactions.

Synthesis and Fluorescence Properties of Structurally Characterized Heterobimetalic Cu(II)⁻Na(I) Bis(salamo)-Based Complex Bearing Square Planar, Square Pyramid and Triangular Prism Geometries of Metal Centers

A novel heterotrinuclear complex [Cu₂(L)Na(µ-NO₃)]∙CH₃OH∙CHCl₃ derived from a symmetric bis(salamo)-type tetraoxime H₄L having a naphthalenediol unit, was prepared and structurally characterized via means of elemental analyses, UV-Vis, FT-IR, fluorescent spectra and single-crystal X-ray diffraction. The heterobimetallic Cu(II)–Na(I) complex was acquired via the reaction of H₄L with 2 equivalents of Cu(NO₃)₂·2H₂O and 1 equivalent of NaOAc. Clearly, the heterotrinuclear Cu(II)–Na(I) complex has a 1:2:1 ligand-to-metal (Cu(II) and Na(I)) ratio. X-ray diffraction results exhibited the different geometric behaviors of the Na(I) and Cu(II) atoms in the heterotrinuclear complex; the both Cu(II) atoms are sited in the N₂O₂ coordination environments of fully deprotonated (L)⁴⁻ unit. One Cu(II) atom (Cu1) is five-coordinated and possesses a geometry of slightly distorted square pyramid, while another Cu(II) atom (Cu2) is four-coordination possessing a square planar coordination geometry. Moreover, the Na(I) atom is in the O₆ cavity and adopts seven-coordination with a geometry of slightly distorted single triangular prism. In addition, there are abundant supramolecular interactions in the Cu(II)–Na(I) complex. The fluorescence spectra showed the Cu(II)–Na(I) complex possesses a significant fluorescent quenching and exhibited a hypsochromic-shift compared with the ligand H₄L.

Synthesis and Fluorescence Properties of a New Heterotrinuclear Co(II)-Ce(III)Complex Constructed from a bis(salamo)-Type Tetraoxime Ligand

[Co₂(L)Ce(OAc)₃(CH₃CH₂OH)]·1.5CH₃OH∙0.5CH₂Cl₂, a heterotrinuclear Co(II)-Ce(III) bis(salamo)-type complex with a symmetric bi(salamo)-type ligand H₄L and an acyclic naphthalenediol moiety, was designed, synthesized and characterized by elemental analyses, FT-IR, UV-Vis and fluorescence spectroscopy and X-ray crystallography. The X-ray crystallographic investigation revealed the heterotrinuclear complex consisted of two Co(II) atoms, one Ce(III) atom, one (L)^4‒ unit, three μ₂-acetate ions, one coordinated ethanol molecule, one and half crystallization methanol molecule and half crystallization dichloromethane molecule. Two Co(II) atoms located in the N₂O₂ coordination spheres, are both hexacoordinated, with slightly distorted octahedral geometries. The Ce(III) atom is nine-coordinated and located in the O₆ cavity possesses a single square antiprismatic geometry. In addition, supramolecular interactions exist in the Co(II)-Ce(III) complex. Two infinite 2D supramolecular structures are built via intermolecular O-H···O, C-H···O and C-H···π interactions, respectively.

Unprecedented Hexanuclear Cobalt(II) Nonsymmetrical Salamo-Based Coordination Compound: Synthesis, Crystal Structure, and Photophysical Properties

A novel hexanuclear Co(II) coordination compound with a nonsymmetrical Salamo-type bisoxime ligandH4L, namely [{Co3(HL)(MeO)(MeOH)2(OAc)2}2]·2MeOH, was prepared and characterized by elemental analyses, UV–vis, IR and fluorescence spectra, and X-ray single-crystal diffraction analysis. Each Co(II) is hexacoordinated, and possesses a distorted CoO6 or CoO4N2 octahedrons. The Co(II) coordination compound possesses a self-assembled infinite 2D supramolecular structure with the help of the intermolecular C–H···O interactions. Meanwhile, the photophysical properties of the Co(II) coordination compound were studied.

Synthesis, crystal structure, luminescence and electrochemical properties of a Salamo-type trinuclear cobalt(II) complex

A trinuclear Co(II) complex, [{CoL(C4H9OH)}2-(OAc)2Co]·C3H7NO, was synthesized by the reaction of a Salamo-type chelating ligand (H2L=4,42′-dinitro-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol) with cobalt(II) acetate tetrahydrate in n-butanol, and characterized by elemental analyses, X-ray crystallography, FT-IR and UV/Vis spectra. In the Co(II) complex, there are two ligand L2− units, two μ 2-acetate ions, two coordinated n-butanol molecules and one non-coordinated N,N-dimethylformamide molecule. The Co(II) atoms in the structure of the Co(II) complex adopt slightly distorted octahedra geometries. Furthermore, through intermolecular C–H···O, O–H···O and C–H···π interactions, infinite layer-like, plane-like and 3D supramolecular structures are constructed. The fluorescence and electrochemical properties of the Co(II) complex have also been investigated.