Synthesis,crystal structures,and antibacterial studies of silver(I) complexes with reduced Schiff base amino acid ligands

Three Ag(I) complexes of reduced Schiff base amino acid ligands, [Ag₂(Hshis)₂]·3H₂O (1), Ag(Hcgly) (2), and Ag(cala) (3) (H₂shis = N-(2-hydroxybenzyl)-l-histidine, H₂cgly = N-(2-hydroxy-5-chlorobenzyl)-glycine, Hcala = N-(4-chlorobenzyl)-d,l-alanine), have been synthesized and characterized by X-ray crystallography. Complex 1 shows a dimeric structure, while complex 2 shows one-dimensional zigzag chains, which are extended into a two-dimensional supramolecular sheet by hydrogen bonds. Complex 3 exhibits a 2D sheet structure with dangling arms. The antimicrobial activities of the complexes have been investigated.     

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.     

Two manganese(II) coordination polymers containing semirigid bis(benzimidazole) ligands: synthesis,crystal structures,and catalytic properties

Two ternary mixed Mn(II) coordination polymers (CPs), namely [Mn(L1)(Hnip)₂] _n (1) and [Mn(H_0.5L2)₂(H_1.5btc)₂] _n (2) (H₂nip = 5-nitroisophthalic acid, L1 = 1, 4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₃btc = 1,3,5-benzenetricarboxylic acid, L2 = 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl), have been synthesized under hydrothermal conditions and structurally characterized. CP 1 exhibits a non-interpenetrated six-connected pcu framework with the point symbol {4¹²·6³}, while CP 2 features a metal-carboxylate loop-like chain, which is further assembled into a 3D supramolecular network via hydrogen bonds and π–π interactions. The thermal stabilities, luminescence, and catalytic properties of both CPs for the degradation of methyl orange in a Fenton-like reaction have also been investigated.     

Synthesis,crystal structures,luminescence, and photocatalytic properties of two 1D Co(II) coordination polymers constructed with semirigid bis(benzimidazole) and dicarboxylate ligands

Two ternary cobalt(II) coordination polymers (CPs), namely [Co(L1)(npht)] _n (1) and {[Co₂(L2)₂(npht)₂(H₂O)]·H₂O} _n (2) (L1 = 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl, L2 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, and H₂npht = 4-nitrophthalic acid) have been synthesized and structurally characterized by X-ray crystallography. Both CPs feature similar 1D infinite chains containing two distinct loops. CP 1 further forms a 3D supramolecular network via weak C–H···O hydrogen bond interactions. CP 2 shows a 1D two-layer chain structure, assembled through π–π stacking interactions. The electrochemical, luminescence, and photocatalytic activities of the two CPs for the removal of methylene blue under visible or UV light were investigated. Possible photocatalytic mechanisms are discussed.     

Blue Photoluminescent Dimeric Cu(I) Dithiophosphates Bridged by a Flexible Ligand 1,2-Bis(4-Pyridyl)Ethane

The title compound {Cu[S₂P(OC₂H₅)₂](bpe)} _n (1) is constructed from flexible ligand bpe (bpe = 1,2-bis(4-pyridyl)ethane) and the Cu[S₂P(OC₂H₅)₂], which was characterized by single crystal structure determination, elemental analysis, XRD, and IR spectra. X-ray diffraction studies revealed that polymeric compound 1 consists of dinuclear module to form 1-D chains with the intramolecular Cu···Cu interactions (ca. 2.63 Å). This interaction may show a profound influence on the observed blue luminescence emission spectrum for 1. Crystal data for 1 at 293(2) K: Space group P ? 1, a = 9.277(3), b = 10.504 (4), c = 31.801(1) Å, α = 92.849(3), β = 90.401(2), γ = 114.547(7)°, V = 2813.9(2) ų, Z = 2, R ₁ = 0.041.     

Molecular and crystal structure of 15-acetylsongorine and songoramine isolated from <Emphasis Type="Italic">Aconitum szechenyianum</Emphasis> Gay

Two napelline skeletal diterpenoid alkaloids 15-acetylsongorine, C₂₄H₃₃NO₄ I, and songoramine, C₂₂H₂₉NO₃ II, were first isolated from the roots of Aconitum Szechenyianum Gay. The crystal structures were determined by X-ray single-crystal diffraction analysis. The crystal I is the triclinic system with space group P1 having unit cell parameters of a = 9.360(8) Å, b = 11.593(9) Å, c = 11.830(16) Å, α = 113.223(15)°, β = 105.950(16)°, γ = 101.296(12)°, and Z = 2. Hydrogen bonds O–H···O and O–H···N joint the molecules into dimer. The crystal II belongs to the orthorhombic system with space group P2₁2₁2₁ having unit cell parameters of a = 8.950(2) Å, b = 13.272(3) Å, c = 15.454(4) Å and Z = 4. The O–H···O hydrogen bonding interaction links the molecule into linear chains. The distortion of rings of compound I and II were evaluated by calculation of the Cremer and Pople puckering parameters. The presence of the C–O–C bond in the compound II results in the changes of ring conformations compared with that of the compound I.     

Directed assembly of cobalt(II) 1-H-indazole-3-carboxylic acid coordination networks by bipyridine and its derivatives: structural versatility,electrochemical properties,and antifungal activity

This paper describes the hydrothermal synthesis, full characterization, and architectural diversity of three intriguingly bioactive cobalt–organic frameworks, namely, 3D [Co(HL ^? )₂(BPY)] _n ·4nH₂O (1), 2D [Co(HL ^? )₂(BPE)] _n (2), and 2D [Co(HL ^? )₂(DPP)] _n (3) coordination polymers, synthesized through a mixed ligand strategy using H ₂ L (1-H-indazole-3-carboxylic acid) as a main structural block and the flexible bipyridine and its derivatives (BPY = 4,4′-bipydine, BPE = 1,2-bis(4-pyridyl)ethane, DPP = 1,3-bis(4-pyridyl)propane) as auxiliary ligand sources. Complexes 1–3 were isolated as air stable and slightly soluble crystalline solids and characterized using elemental analysis, FT-IR, electrochemical technique, thermogravimetric analysis, powder X-ray diffractometer, and single-crystal X-ray crystallography. The bipyridine derivatives played key roles in defining the structural space group and dimensionality feature of the obtained networks. The abundant H-bonding and π–π stacking interactions in complexes 1–3 gave rise to their intricate metal–organic structures of 3D (1), 2D (2), and 2D (3). In addition, the solutions of complexes 1–3 showed profound antifungal activities against the selected strain of Colletotrichum musae compared with the controlled group using benomyl as a traditional agrochemical fungicide.     

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.     

Alternative preparation and characterization of platinum(II) organometallic dinuclear complexes and oligomers with 3,8-diethynylphenanthroline derivatives

Novel platinum(II) organometallic dinuclear complexes and oligomers with two types of phenanthroline ligands, namely 3,8-diethynylphenanthroline (L1) and 3,8-bis-(4-ethynyl-phenylethynyl)-1,10-phenanthroline (L2), were synthesized from trans-Pt(PBu₃)₂(1-ethynyl-4-methyl-benzene)Cl and trans-Pt(PBu₃)₂Cl₂ by transmetalation of copper ion. The alternative procedure targeted platinum oligomer termination selection of either chloride or respective phenanthrolines and was successfully performed with different purifications by extraction and column chromatography. The structural formulae of these platinum complexes and oligomers were revealed with by analysis of both ³¹P{¹H}-NMR and ¹H-NMR spectral data. Alternative preparations of platinum oligomers with two types between chloride and respective phenanthroline termination are very useful for the selective synthesis for hybrid polymers with the coupling reaction with two different platinum oligomers with different diethynylaryl ligands. The platinum organometallic compounds showed similar absorption bands in the UV–Vis region. Those prepared with L1 had a strong absorption band at around 400 nm, assignable to the lowest energy metal-perturbed ¹[π–π*] transitions, while in compounds prepared with L2, the strong band appeared around 410 nm, because L2 has an extended π conjugation relative to L1. No distinct differences were observed in the absorption spectra of these platinum oligomers between the different terminal structures, chloride or various phenanthrolines. The luminescence spectra of the platinum compounds prepared with either L1 or L2, however, showed a distinct difference. Those with L1 showed only a phosphorescence assignable to a typical metal-perturbed ³[π–π*] transition with vibronic progressions centered at around 530 nm in deoxygenated CH₂Cl₂ at room temperature, while those with L2 showed weak dual emissions assignable to a mixture of typical metal-perturbed ¹[π–π*] and ³[π–π*] transitions in the visible region.     

Structural aspects of some organoselenium compounds

The crystal structures of four organoselenium compounds, viz. bis(2-formylphenyl)diselenide (5), bis(2-methylnaphthyl)diselenide (6), organoselenenyl sulfide (7), and spiroselenurane (8) are described. Crystal data for 5: space group Pca2₁, crystal system orthorhombic, a=7.9969(4) Å, b=20.8794(12) Å, c=15.8307(13) Å, Z=8, R=0.0292. Owing to the presence of a strong Se···O interaction in compound 5 the geometry around the selenium atom may be considered as T-shaped. Crystal data for 6: space group Pna2₁, crystal system orthorhombic, a=18.2253(12) Å, b=13.0714(8) Å, c=7.7355(5) Å, Z=4, R=0.0570. The molecule has a cisoid conformation. Crystal data for 7: space group Pbcn, crystal system orthorhombic, a=22.2144(13) Å, b=8.0255(4) Å, c=15.4496(9) Å, Z=8, R=0.0292. Due to intramolecular Se···N interaction in 7 the geometry around selenium is T- shaped. Crystal data for 8: space group P2₁/c, crystal system monoclinic, a=7.4585(5) Å, b=19.5634(13) Å, c=8.0428(5) Å, β=97.1320(10)°, Z=4, R=0.0254. The O?Se?O angle is 172.86(6)°.     

Organic/Bismuth Iodides Hybrids: Structural Perturbation of Substitutes and Their Photocurrent Response Properties

Two new organic/bismuth halides hybrids, (Et₂DABCO)₂(Bi₂I₁₀) (1) and (Pr₂DABCO)₂(Bi₂I₁₀) (2) (Et₂DABCO²⁺ = N, N’-diethyl-1,4-diazabicyclo[2.2.2] octane, Pr₂DABCO²⁺ = N, N’-diproyl-1,4- diazabicyclo[2.2.2] octane) have been synthesized. Both hybrids contain (Bi₂I₁₀)^4? halobismuthate dimers and (Et₂DABCO)²⁺/(Pr₂DABCO)²⁺ cations, and C–H···I hydrogen bonds contribute to the structural extending from 0-d clusters to 2-d layer (for 1) and 3-d network (for 2). Theoretical calculations were conducted to reveal the perturbation effects of 1,4-diazabicyclo[2.2.2] octane substitutes on their structures. Their absorption spectra were investigated, and energy band gaps of 2.10/2.16 eV indicate their narrow-gap semiconductor natures. Their photocurrent response properties were also discussed.     

Synthesis,characterization, and crystal structures of 2D cobalt(II) and nickel(II) coordination polymers containing flexible bis(benzimidazole) ligands

Three coordination polymers, namely {[Ni(L1)(nip)(H₂O)]·2H₂O} _n (1), [Co(L2)(tbip)] _n (2), and {[Co₂(L3)₂(bptc)]·3H₂O} _n (3) (L1 = 1,4-bis(5,6-dimethylbenzimidazole)butane, L2 = 1,4-bis(5,6-dimethylbenzimidazole)-2-butylene, L3 = 1,3-bis(5,6-dimethylbenzimidazole)propane, H₂nip = 5-nitro-isophthalic acid, H₂tbip = 5-tert-butyl-isophthalic acid, H₄bptc = biphenyl-3,3′,4,4′-tetracarboxylic acid), have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Complexes 1 and 2 both feature a two-dimensional (4,4) layer with (4⁴ × 6²) topology. Complex 3 possesses a uninodal 4-connected 2D htb network. The fluorescence spectra and catalytic properties of the complexes for the degradation of methyl orange by sodium persulfate in a Fenton-like process are reported.     

Crystal structure,spectroscopic and thermal properties of copper(II) and manganese(II) coordination polymers based on triazole-benzoic acid ligands

Two transition metal coordination polymers {[Cu(tba)₂(H₂O)]·2H₂O} _n (1) and {[Mn(Htta)₂(H₂O)₂]·2H₂O} _n (2) {Htba = 3-[1,2,4]triazol-1-yl-benzoic acid, H₂tta = 2-[1,2,4]triazol-1-yl-terephthalic acid} have been synthesized under solvothermal conditions. Both complexes have been characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis and FTIR spectroscopy. Complex 1 has a 1-D chain structure in which Cu(II) atoms are doubly bridged by tba^? ligands, which is further stabilized by hydrogen bonding and π–π stacking interactions to give a 3-D supramolecular framework. In complex 2, Mn(II) atoms are doubly bridged by Htta^? ligands to form 1-D chains, which are further connected by intermolecular hydrogen bonds to form a 3-D supramolecular framework. The electronic spectra and thermal behaviors of complexes 1 and 2 are also reported.     

Effective reduction of <Emphasis Type="Italic">p</Emphasis>-nitrophenol catalyzed by nickel(II) adamantane complexes

Two Ni(II) adamantane complexes, [Ni(bqad)Cl₂] (1) and [Ni(bpad)(dmbp)(H₂O)](ClO₄)₂·CH₃OH H₂O (2) (bqad = N,N′-bis(2-quinolinylmethyl) amantadine, bpad = N,N′-bis(2-pyridylmethyl)amantadine, dmbp = 5,5′-dimethyl-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, infrared spectroscopy and single crystal X-ray diffraction. The nickel centers in complex 1 have a distorted tetragonal pyramidal geometry, while the coordination polyhedron of 2 can be described as a distorted octahedron. The reaction kinetics for reduction of p-nitrophenol to p-aminophenol catalyzed by these complexes has been investigated by UV–visible spectrophotometry. Complex 1 exhibits a higher turnover frequency of 1.4 min^?1 for the reduction of p-nitrophenol.     

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.     

Self-Assembly,Crystal Structure and Analysis of Intermolecular Interactions of the Supramolecular Compound Based on Hexamolybdochromate(III), Sulfate and Piperazine

A new supramolecular compound based on Anderson-B hexamolybdochromate, (H₂Pz)₃[Cr(OH)₆Mo₆O₁₈H](SO₄)₂·12H₂O (1) (Pz = piperazine) was synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction (Mo Kα). The compound crystallizes in monoclinic system, P21/c space group with a = 13.5708(6) Å, b = 17.3711(8) Å, c = 22.2387(9) Å, β = 110.631(2)°; V = 4906.3(4) Å³, Z = 4, D _c  = 2.290 g/cm³, F(000) = 3364.0; μ = 1.905, S = 1.033. The final R = 0.0398 and wR = 0.0971. The H₂pz²⁺ ions and sulfate anions in 1 are arranged through hydrogen bonds into a hexagonal network in [202] plane and hexamolybdochromates anions (CrMo₆) fill in the hexagonal vacancies. The networks stack in such a way that each anion links two sulfate ions from adjacent networks via hydrogen bonds with short (CrMo₆)O···OSO₃ distances of 2.637–2.697 Å. A lot of hydrogen bonds are formed between water molecules, sulfate, H₂pz²⁺ ions and CrMo₆ anions, which are the dominating force constructing the supramolecular structure. Hirshfeld surface analysis of 1 gives us the details of intermolecular interactions in the crystals of 1 in a visual manner and shows that the CrMo₆ anion acts as a stronger hydrogen bond donor than as an acceptor.     

Bioactive compounds from <Emphasis Type="Italic">Smilax excelsa</Emphasis> L.

Phytochemical investigation of EtOAc extract of Smilax excelsa has led to isolation and structure elucidation of five compounds. The structures of these compounds are established by different spectroscopic techniques including 1D and 2D-NMR, HRMS and ECD spectroscopy. The compounds were: solanesol (1), violasterol A (2), trans-resveratrol (3), 5-O-caffeoylshikimic acid (4) and 6-O-caffeoyl-β-d-fructofuranosyl-(2-1)-α-d-glucopyranoside (5). The configuration of compound 2 was established by electronic circular dichroism (ECD) spectroscopy. Meanwhile the cytotoxicity and antibacterial activity of the compounds were evaluated by MTT and MIC assays. Compounds 1 and 2 showed promising inhibition on MCF-7 cell line with IC₅₀ of 161.6 and 190.0 µM, respectively. Also compounds 2 and 3 illustrated activity against Staphylococcus aureus with MIC values of 142.5 and 136.9 µM, respectively.     

Two new mononuclear cobalt(II) complexes of pyrazole-based ligands: synthesis,structures and magnetic studies

We have synthesized two mononuclear cobalt(II) complexes (1 and 2) of pyrazole-based bidentate (NN) and tridentate (NNN) tripodal ligands. X-ray crystal structure determination reveals that complex 1 has a tetrahedral geometry, while complex 2 has a trigonal–bipyramidal geometry. Both the complexes have been characterized by variable-temperature magnetic measurements between 2 and 300 K. A weak ferromagnetic exchange interaction (J = +1.5 cm^?1) is observed for complex 2. Due to the presence of supramolecular CH···Cl and π···π interactions, a good magnetostructural correlation was found between the D parameter and angular distortion (δ) for complex 1 and related complexes reported in the literature.     

Synthesis,crystal and molecular structures of 1D and 2D supramers of copper(II) with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-{bis(pyridin-2-yl) benzylidene}butane-1,4-diamine

Reaction of copper(II) perchlorate with N,N′-{bis(pyridin-2-yl)benzylidene}butane-1,4-diamine (bpbd) yielded monoclinic crystals of bluish green [Cu(bpbd)(ClO₄)]ClO₄ (1), and a similar reaction in presence of azide anion, N₃ ^? formed monoclinic crystals of dark green [Cu(bpbd)(N₃)]₂ClO₄ (2). Crystal data for 1: space group P21/c, Z=4, a=17.3968(4) Å, b=9.3182(2) Å, c=17.6794(4) Å, β=102.149(1)°. The geometry around Cu(II) centre is distorted square pyramidal with axial site occupied by O atom of perchlorate and in plane Cu is bonded to four N atoms of the organic ligand. The intermolecular C–H...π stacking in 1 forms a zigzag chain (1D) supramer. Crystal data for 2: space group C2/c, Z=4, a=22.3109(4) Å, b=17.7832(3) Å, c=14.3389(2) Å, β=92.553(1)°. In dinuclear 2, Cu(II) has tetragonally distorted octahedral geometry coordinated by four N atoms of bpbd, with the fifth and sixth positions occupied by N atoms of two end-on bridging azides. The π...π interaction leads to a two dimensional (2D) sheet within which the counter anions are embedded. Both the compounds 1 and 2 show simple paramagnetism. Cyclic voltammetry and fluorescence spectra are also reported.     

Laterally non-symmetric aza cryptand molecules stitched by water

Crystal structure of the compound L·4H₂O (L = aza cryptand) and its supramolecular assembly via H-bonding through water molecules are described here. The compound crystallizes in the cubic space group Pa3 (no. 205) with the following lattice parameters: a=b=c=19.023(2) Å, V=6883.9(4) Å³, Z=8, R ₁=0.0592, wR ₂ = 0.1572, S=0.964.