Supramolecular assembly of three Ag(I) coordination polymers derived from flexible N-containing ligands and polycarboxylates: synthesis,structures, and catalytic properties

Three Ag(I) coordination polymers [Ag(L1)]·(H₃bptc)·H₂O (1), [Ag₂(L2)(oba)]·H₂O (2), and [Ag₂(L2)₂]·(H₂bptc) (3) [L1 = 1,4-bis(3,5-dimethylpyrazole)butane, L2 = 1,4-bis(2-methylbenzimidazole)butane, H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, H₂oba = 4,4′-oxybis(benzoic acid)] constructed from N-containing ligands with different flexibilities and organic carboxylates as co-ligands have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis. All three complexes display 1D chain structures, which are further extended into 2D supramolecular networks via non-classical C–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of the complexes 1–3 have been investigated in detail. Complexes 2 and 3 reveal promising catalytic activities for the degradation of methyl orange in a Fenton-like process.     

Diverse topologies of three cobalt(II) coordination polymers constructed from flexible bis(benzimidazole) and dicarboxylate ligands

Three cobalt(II) coordination polymers {[Co(L1)(nda)(H₂O)₂]·2H₂O} _n (1), [Co(L2)(tbi)(H₂O)] _n (2) and [Co(L2)(bpdc)(H₂O)] _n (3) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol, L2 = 1,3-bis(benzimidazol-1-yl)-2-propanol, H₂nda = 2,6-naphthalenedicarboxylic acid, H₂tbi = 5-tert-butyl isophthalic acid and H₂bpdc = 4,4′-biphenyldicarboxylic acid) were synthesized and characterized by physicochemical and spectroscopic methods. Complex 1 exhibits a 1D loop-like structure, which is further extended into a 3D 3,3,4T31 network through two O–H···O hydrogen bonding interactions. Complex 2 displays a 1D ladder-like chain, arranged into a 2D supramolecular network with 3,3,4L34 topology via classical O–H···O hydrogen bonding interactions, whereas complex 3 features a 2D 3,4L13 layer structure and further assembles into a 3D framework with a twofold interpenetrating sqc65 topology through O–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of these complexes for the degradation of Congo red in a Fenton-like process have been investigated.     

Syntheses,structures and properties of complexes of indole-3-propionic acid

Three complexes [Zn₂(IPA)₂(phen)₄](HIPA)₂(NO₃)₂·H₂O (1), {[Zn(IPA)₂(bipy)]·3H₂O}_n (2), and {[Mn(IPA)₂(bipy)(H₂O)]·2H₂O}_n (3) (HIPA = indole-3-propionic acid, phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine) were synthesized and characterized by physico-chemical and spectroscopic methods. Complex 1 displays a zero-dimensional structure, whilst 2 and 3 show one-dimensional chains, which are linked into supramolecular networks through hydrogen bonding interactions and/or π···π stacking interactions. The luminescence properties of complexes 1 and 2 were investigated.     

Polyoxometalate-based supramolecular hybrids composed of Cu/2, 2′-dimethyl-4, 4′-bithiazole fragments extended via non-bonding S···O interactions

Four polyoxometalate-based complexes, namely [Cu^I(dm4bt)₂]₃[PMo₁₂O₄₀] (1), H₂[Cu^I(dm4bt)₂]₂{[Cu ₂ ^I (dm4bt)₃]₂[SiW₁₂O₄₀]}[SiW₁₂O₄₀] (2), [Cu^I(dm4bt)₂]₅ {[Cu^I(dm4bt)][P₂W₁₈O₆₂]} (3) and {Cu ₂ ^II (dm4bt)₂[Mo₆O₂₀]} (4) (dm4bt = 2,2′-dimethyl-4,4′-bithiazole), were synthesized hydrothermally from copper nitrate and various polyoxoanions. X-ray crystal structural analysis reveals that all four complexes have supramolecular structures, in which the dm4bt ligands coordinate with the Cu atoms to give different Cu/dm4bt fragments, which are further connected into supramolecular structures via non-bonding S···O interactions between Cu/dm4bt fragments and polyoxoanions. The crystal structures also reveal the crucial role of S···O interactions in the packing structures of complexes 1–4. The electrochemical and electrocatalytic properties of 1–3 with respect to bromate reduction were investigated.     

Three cobalt(II) coordination polymers constructed from flexible bis(thiabendazole) and dicarboxylate linkers: crystal structures,fluorescence, and photocatalytic properties

Three Co(II) coordination polymers, namely, {Co(btbb)_0.5(ndc)(H₂O)}_n (1), {[Co(btbb)(bpdc)]·1.5H₂O}_n (2), and {[Co(btbp)₂(3-npa)]·2H₂O}_n (3) (btbb = 1,4-bis(thiabendazole)butane, btbp = 1,3-bis(thiabendazole)propane, H₂ndc = 2,6-naphthalenedicarboxylic acid, H₂bpdc = 4,4′-biphenyldicarboxylic acid and 3-H₂npa = 3-nitro phthalic acid) were synthesized under hydrothermal conditions. Their X-ray crystal structures show that complexes 1 and 2 both have 2D uninodal 3-connected hcb (honeycomb) structures. Complex 1 is further extended into a threefold interpenetrating 3D 4,4-connected mog (moganite) supramolecular architecture with the point symbol of {4.6⁴.8}₂{4².6².8²} by O–H···O hydrogen bonding interactions. Complex 2 shows a 3D supramolecular framework involving π···π stacking interactions. Complex 3 features a uninuclear structure, which is further assembled into an ordered 2D hydrogen-bonded-driven pattern with O–H···O and O–H···N hydrogen bonding interactions. The fluorescence spectra and photocatalytic properties of complexes 1–3 for degradation of methyl orange were investigated.     

Substituted group-directed assembly of six coordination compounds based on pyrazole bifunctional ligands

Six new complexes [Mn₈(μ₄-O)₄(phpz)₈(MeOH)₄]·(MeOH)(H₂O) (1) [Co₂(HphpzH)(Hphpz)₂(phpz)₂]·4(MeOH) (2), Ni(Hphpz)₂ (3), [Ni(Hphpz)₂]·H₂O (4), [Zn₄(pzpy)₄Cl₄] (5) and [Cu₂(pzpy)₂(HCO₂)₂(H₂O)₂] (6) have been synthesized by hydrothermal reactions of MCl₂·4H₂O (M = Mn, Co, Ni, Zn or Cu) with 5-(2-hydroxyphenyl)-3-pyrazole (HphpzH) or 2-(1H-pyrazol-3-yl)pyridine (Hpzpy). The complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 is an octanuclear Mn(III) cluster, complexes 2 and 6 are binuclear Co(III) and Cu(II), respectively, complexes 3 and 4 are isomorphous mononuclear species, while complex 5 is a tetranuclear Zn(II) cluster. The magnetic behavior of complex 1 was investigated. Magnetic susceptibility measurements revealed antiferromagnetic exchange interactions between the metal centers in the clusters. The luminescence properties of the complexes were investigated at room temperature in the solid state.     

Syntheses,crystal structures and in vitro anticancer activities of oxovanadium(IV) complexes of amino acid Schiff base and 1,10-phenanthroline ligands

Four oxovanadium(IV) complexes, namely [VO(desa-met)(phen)]·MeOH·2H₂O (1) (desa-met = Schiff base derived from 4-(diethylamino)salicylaldehyde and dl-methionine, phen = 1,10-phenanthroline), [VO(o-van-met) (phen)]·MeOH·CH₂Cl₂·3H₂O (2) (o-van-met = Schiff base derived from o-vanillin and dl-methionine), [VO(dtbs-napa)(phen)]·2H₂O (3) (dtbs-napa = Schiff base derived from 3,5-di-tert-butyl salicylaldehyde and 3-(1-naphthyl)-l-alanine) and [VO(hyna-napa)(phen)]·1.5H₂O (4) (hyna-napa = Schiff base derived from 2-hydroxy-1-naphthaldehyde and 3-(1-naphthyl)-l-alanine), were synthesized and characterized by IR, HRMS, UV–vis spectra, molar conductance and single-crystal X-ray diffraction (XRD). X-ray structural analysis showed that the V(IV) atoms in all four complexes are six-coordinated in a distorted octahedral environment. In the crystals of complexes 1 and 2, π–π stacking interactions together with hydrogen bonds connect the molecular units into 2D networks. Meanwhile, CH–π stacking interactions are observed between the aromatic rings in the crystals of 1 and 4, while the π–π stacking interactions between aromatic rings in the crystals of 2 and 3 are arranged with a face-to-face mode. The in vitro anticancer activities of these complexes against A-549 and HeGp2 cells were tested by MTT assay.     

Synthesis,crystal structures and photocatalytic properties of four silver(I) coordination polymers based on semirigid bis(pyrazole) and carboxylic acid co-ligands

Four Ag(I) coordination polymers, formulated as [Ag(L1)(tpa)_0.5] _n (1), {[Ag(L2)(ndc)_0.5]·0.5H₂ndc} _n (2), [Ag(L3)_0.5(ndc)_0.5] _n (3) and {[Ag(L3)]·H₃bptc} _n (4) (L1 = 4,4′-bis(pyrazole-1-ylmethyl)-biphenyl, L2 = 4,4′-bis(3,5-dimethylpyrazol-1-ylmethyl)-biphenyl, L3 = 1,4-bis(3,5-dimethylpyrazol-1-ylmethyl)benzene, H₂tpa = terephthalic acid, H₂ndc = 2,6-naphthalenedicarboxylic acid, H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid), have been hydrothermally synthesized and structurally characterized. Complex 1 features the rare binodal (4,4)-connected 2D 4,4L10 topological network with a point symbol of {3²·4.6²·7}₂{3²·6²·7²}. Complex 2 has a folded ladder-like chain structure, which is further extended into a 3D supramolecular network via O–H···O hydrogen bonding and π···π stacking interactions. Complexes 3 and 4 both possess 1D zigzag chain structures. Complex 3 is further extended into a binodal (3,4)-connected network with the point symbol of {4.8⁴·10}{6²·8²}₂ by Ag···O weak interactions, while complex 4 is further connected through O–H···O hydrogen bonding and π···π interactions to afford a 2D supramolecular structure. The photoluminescence spectra and photocatalytic properties of these complexes for degradation of methylene blue and methyl orange are reported.     

A series of 3d metal complexes prepared by in situ reactions of a flexible diacylhydrazine ligand: synthesis,structures and magnetic properties

The coordination reactions of 3d metal salts with malonic acid N,N′-bis(salicyloyl) bishydrazide (H₆mbshz) afforded three complexes, namely [Cu₂(H₂bshz)(Py)₄Cl₂]·Py (1) (Py = pyridine), [Fe₂(bshz)(Py)₂] (2) and the known complex [Ni₄(aehba)₂(DMF)₂(H₂O)₂]·2DMF (3), where bshz = N,N′-bis(salicyloyl)hydrazine anion and aehba^4? = azo-enolic-2-hydroxybenzamide anion. The X-ray crystal structures of all three complexes have been obtained. Complexes 1 and 2 are composed of N–N-bridged binuclear units, while complex 3 displays a planar tetranuclear structure in which four Ni(II) centers are linked together by N–N and N=N bonds. The bshz anions in 1 and 2 and aehba^4? anions in 3 were all generated in situ from H₆mbshz. A mechanism for these reactions is proposed, involving tandem C–N cleavage and C–N/N–N coupling processes via free radical intermediates. Magnetic investigations revealed dominant antiferromagnetic interactions between the metallic centers of each complex.     

Syntheses,characterization, and magnetic properties of two 3D frl topological frameworks constructed from nickel diphosphonates

Two 3D open-framework nickel diphosphonates, [Ni₃(H₂zdn)₂(bpe)₂]·4H₂O (1) and [Ni₃(H₂zdn)₂(bpy)₂]·bpy·4H₂O (2) (H₅zdn = zoledronic acid, bpe = trans-4,4-vinylenedipyridine, bpy = 4,4′-dipyridyl), have been prepared and structurally characterized. In complex 1, the metal centers are linked by zoledronate ligands to generate a 2D layer, containing 14- and 24-membered rings. These 2D layers are further pillared by the bpe ligands into a 3D network structure with cylindrical channels. Magnetic susceptibility measurements reveal ferrimagnetism at T _c = 3.8 and 4.4 K for complexes 1 and 2, respectively.     

Syntheses,crystal structures,and DNA binding and catalytic properties of two transition metal coordination polymers constructed from 5-aminoisophthalic acid and bis-benzimidazole ligands

Two mixed-ligand transition metal coordination polymers, {[Co(aip)(bbp)]·(H₂O)} _n (1) and {[Ni₂(aip)(Hbbop)₂]·(H₂O)₂} _n (2) (H₂aip = 5-aminoisophthalic acid, bbp = 1,3-bis(benzoimidazol-2-yl)propane, H₂bbop = 1,3-bis(benzimidazol-2-yl)-2-oxapropane), were synthesized and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, and thermogravimetric analyses. Complex 1 has a 1D chain structure, while 2 has a 3-connected 2D network with (6³) topology. Both structures are further connected by hydrogen bonds and π–π stacking interactions to form the 3D supramolecular architectures. DNA binding and catalytic properties of the two complexes were investigated.     

Three metal complexes based on tetrazolyl ligands: Hydrothermal syntheses,crystal structures,and fluorescence properties

Three new complexes based on 1-tetrazole-4-imidazole-benzene (Tibz), namely, [Cd(Tibz)₂(H₂O)₂] _n (I), [Mn(Tibz)₂(H₂O)₄] · 2H₂O (II) and [Co(Tibz)₂(H₂O)₄] · 2H₂O (III) have been synthesized through hydrothermal method and structurally characterized by element analyses, IR spectroscopy and single-crystal X-ray diffraction analyses (CIF files CCDC nos. 1443867 (I), 1443868 (II), 1443869 (III)). Single-crystal X-ray diffraction reveals that complex I is a 1D double-chain architecture, II and III are both mononuclear complexes. The results of single-crystal X-ray diffraction analyses indicate that the hydrogen bond and π··· π stacking exist in the complexes, which make great contribution to the stabilities of complexes I–III. The fluorescent properties of these complexes have also been studied in the solid state at room temperature.     

Four novel metal–organic frameworks based on 3,4,7,8-tetramethyl-1,10-phenanthroline: Syntheses,structures, and thermal properties

Four novel metal–organic frameworks, [Cu(Tmp)₂(H₂O)] · NO₃ (I) (Tmp = 3,4,7,8-tetramethyl-1,10-phenanthroline), [Mn(Tmp)₂(H₂O)₂] · 2NO₃ · H₂O (II), [Pb(Tmp)(CH₃COO)₂] · 3H₂O (III) and [Zn(Tmp)₂(H₂O)₂] · 2NO₃ · 2H₂O (IV), have been synthesized and characterized by single crystal X-ray diffraction (CIF files CCDC nos. 88362–88365 for I–IV, respectively), IR spectroscopy, elemental analysis and thermogravimetric analysis. Both I and II complexes are crystallized in monoclinic system with space groups C2/c, P2₁/c, respectively, while III and IV complexes are crystallized in triclinic system with space groups \(P\overline 1 \). Generally, these crystal structures are stabilized by O–H···O hydrogen bonds and π–π interactions between the phenanthroline rings of neighboring molecules. Thermogravimetric analyses of compounds I–IV display considerable thermal stability.     

A Disc-Like Heptanuclear Nickel Cluster Based on Schiff Base: Synthesis,Structure, Magnetic Properties and Hirshfeld Surface Analysis

A new disc-like heptanuclear cluster [Ni₇(immep)₆(MeO)₆]·(NO₃)₂ (1, Himmep is 2-imminomethyl-6-ethxoy-phenol) was synthesized through microwave assisted reaction of Ni(NO₃)₂·6H₂O with 2-hydroxy-3-ethoxy-benzaldehyde and ammonium water in mixed solvent (acetonitrile:methanol = 1:1). 1 was characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. Magnetic property of 1 was discussed. The core of 1 displays dominant ferromagnetic interactions from the nature of the binding modes through μ ₃-OCH₃. According to the 3D Hirshfeld surface and 2D fingerprint plots, the main interactions in 1 are the H···H, O···H, and C···H contacts.     

Transition metal complexes of a hydrazone derived from hydralazine hydrochloride and 3,5-di-tert-butylsalicylaldehyde

Mononuclear Co(III), Ni(II) and Cu(II) coordination compounds of (E)-1-(3,5-di-tert-butyl-2-hydroxybenzylidene)-2-(phthalazin-1-yl)hydrazine (LH) were prepared and characterized by physicochemical and spectroscopic methods. The metal-to-ligand ratio was found to be 1:2 in [Co(L)₂]Cl·2H₂O (1) and [Ni(L)₂]·2H₂O (2), while it is 1:1 in [Cu(L)Cl]·2CH₃OH (3). The X-ray crystal structures of LH and complex 1 is are reported. LH shows monobasic behavior, coordinating through NNO donor atoms. The complexes were investigated for their antimicrobial properties. Complexes 1 and 3 show excellent antibacterial and antifungal activities, respectively.     

Syntheses,Crystal Structures and Luminescent Properties of Drum and Ladder-Like Organooxotin Clusters with Carbazole Ligand

Four new Organooxotin Clusters: [(p-MeC₆H₄)Sn(O)L¹]₆ (1) (HL¹ = 2-(9H-carbazol-9-yl)acetic acid), [PhSn(O)L²]₆·2C₆H₆·2H₂O (2) (HL² = 3-(9H-carbazol-9-yl)propanoic acid), [n-BuSn(O)L²]₆ (3), [(c-Hex₂Sn)₂(L¹)O(OH)]₂·3C₆H₆ (4), were synthesized with benzene being used as solvent in the reaction and characterized by elemental analysis, IR, NMR spectroscopy and X-ray crystallography diffraction analyses. Complexes 1–3 are hexanuclear organotin complexes with drum structure. Complex 4 is dimeric carboxylate tetraorganodistannoxane and shows a ladder structure. There are four crystallographically unique Sn centers in the structure of 4, which consists of a Sn₄O₂(OH)₂ ladder unit, and the ladder consists of four tins held together by four µ₃-oxygens. All the complexes show an extensive supramolecular organization in the solid state and form 1D or 2D supramolecular assembly mediated by C–H…O, C–H…π or π…π interactions. Moreover, complexes 1 and 4 exhibit good fluorescence properties in the solid state revealed by the luminescent investigation. The experimental results show the complexes may be explored for potential luminescent materials.     

Four Mixed 3d-4f 12-Metallacrown-4 Complexes: Syntheses,Structures and Magnetic Properties

The incorporation of Ln^III ions into the 12-metallacrown-4 topology affords the formation of four mixed 3d-4f pentanuclear complexes of compositions [NH(C₂H₅)₃]{[Ln(OAc)₄] [12-MC _Mn ^III _(N)shi-4]}·xH₂O (Ln = Sm (1), Gd (2), Tb (3), Dy (4); x = 0.5 for 1 and 3, x = 0.25 for 2, x = 0 for 4; H₃shi = salicylhydroxamic acid). Compounds 1–4 were obtained from the reactions of H₃shi with Mn(CH₃COO)₂·4H₂O and Ln(NO₃)₃·6H₂O, in the presence of N(C₂H₅)₃. They all contain a crown-like [Mn₄Ln(μ-NO)₄]¹¹⁺ core with four Mn^III atoms being at the rim of the crown and an Ln^III ion occupying the dome of the crown. The peripheral ligation about the core is provided by four η¹:η¹:µ acetate groups. The identity of the Ln^III ions slightly affects the 12-metallacrown-4 frameworks, as demonstrated by the gradual decrease of the distances between the Ln^III ions and the centres of the Mn₄ planes (1.85 Å for 1, 1.81 Å for 2, 1.80 Å for 3, and 1.77 Å for 4). Variable-temperature dc magnetic susceptibility studies were carried out on polycrystalline samples of 1–4. Antiferromagnetic interactions are determined for complexes 1–4.     

Four supramolecular transition metal(II) complexes based on triazole-benzoic acid derivatives: crystal structure,Hirshfeld surface analysis,and spectroscopic and thermal properties

Four new complexes [M(3-tba)₂(H₂O)₄] (1–3) and [Co(4-tba)₂(H₂O)₄] (4) {M = Zn (1), Ni (2), Co (3), 3-Htba = 3-(1H-1,2,4-triazol-1-yl)benzoic acid, 4-Htba = 4-(1H-1,2,4-triazol-1-yl)benzoic acid} have been synthesized under solvothermal conditions and structurally characterized by single crystal X-ray diffraction. Complexes 1–4 are also determined by elemental analysis, X-ray powder diffraction, IR and electronic spectroscopy. Single crystal X-ray diffraction reveals that complexes 1–3 are isostructural and they crystallize in the orthorhombic space group of Pbca, while complex 4 belongs to triclinic system with Pī space group. Based on different intermolecular hydrogen bonding and π···π stacking interactions, complexes 1–4 further assembled into 3D supramolecular frameworks. Hirshfeld surface analysis was used to further study the intermolecular interactions of the complexes. The thermogravimetric analyses (TGA) reveal that these complexes possess good thermal stability, and the differential scanning calorimetry (DSC) analyses show intense exothermic phenomena in the decomposition processes of triazole groups. Besides, the photoluminescence property of complex 1 in the solid state is also determined.     

Synthesis,crystal structures and magnetic properties of three complexes containing bis(maleonitriledithiolate) copper(II) anion and <Emphasis Type="Italic">meta</Emphasis>-substituted benzyl isoquinolinium cations

Three complexes, [3RBzIQl]₂[Cu(mnt)₂] (mnt^2? = maleonitriledithiolate; [3RBzIQl]⁺ = 1-(3′-R-benzyl)isoquinolinium, R = Cl (1), I (2) or NO₂ (3)), have been prepared and characterized by spectroscopic and physicochemical methods as well as by X-ray crystallography. The [Cu(mnt)₂]^2? anions formed a 1D chain in complex 1, a dimer in 2 and a sheet structure in 3 through C···N and/or N···N interactions. The neighboring dimers of the cations arranged in a boat-type pattern stack into columns through weak π···π, Cl···π or O···π, C–H···π interactions. The anions and cations stack together into a columnar structure with a ···A–CC–A–CC–A··· sequence. The magnetic susceptibilities measured in the temperature range 2.0–300 K reveal that complex 1 undergoes a change from weak ferromagnetic to antiferromagnetic exchange around 132 K, while 2 shows antiferromagnetic behavior and 3 shows a weak ferromagnetic interaction when the temperature is lowered.     

Hydrogen Bonding and Iodine Bonding Interactions in Sustaining Two Coordination Polymers Base on Square Grids and Tetranuclear Cobalt Clusters

Two new coordination polymers [Co(H₂O)₂(bpy)₂]·2(Adi) (1) and [Co₄(OH)₂(Adi)₆(bpe)₂] (2) (HAdi = 4-amino-3,5-diiodobenzoic acid, bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethylene) have been synthesized by methods of hydrothermal reactions and their crystal structures determined. In 1, the mononuclear Co atoms are linked by bpy ligands forming cationic two-dimensional square grids, which are connected by the intercalated Adi guest molecules through significant hydrogen-bonding interactions to give a three-dimensional supramolecular porous network with one-dimensional channels. 2 has a one-dimensional chain structure based on rhombic tetranuclear Co^II clusters, connected by bpe ligands. Through special I···I interactions, adjacent chains are extended into a three-dimensional supramolecular structure. The structure versatility indicates that the amino and iodo groups of Adi ligands play a crucial role in modulating the coordination polymers. A discussion of the crystal structures, thermal stabilities, as well as the noncovalent interactions of Adi molecules is provided. IR, elemental analysis and XRPD confirmed the phase purity of the bulk materials. Magnetic properties of 2 in the 300–2 K have been discussed, which reveal the occurrence of antiferromagnetic interactions between Co^II ions.