Five new cobalt(II) complexes based on indazole derivatives: synthesis,DNA binding and molecular docking study

Five cobalt(II) complexes based on 1H-indazole-3-carboxylic acid (H₂L), [Co(phen)(HL)₂]·2H₂O (1), [Co(5,5′-dimethyl-2,2′-bipy)(HL)₂] (2), [Co(2,2′-bipy)₂(HL)₂]·5H₂O (3), [Co₂(2,9-dimethyl-1,10-phen)₂(L)₂] (4) and [Co₂(6,6′-dimethyl-2,2′-bipy)₂(L)₂]·H₂O (5) (2,2'-bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and structurally characterized by elemental analyses, IR and UV-vis spectroscopies and single-crystal X-ray crystallography. The results indicate that 1–3 possess mononuclear Co(II) structures, while 4 and 5 exhibit binuclear structure. 1D water tape which is linked by the multiple hydrogen bonds was embedded in the 3D motif of complex 3. Complexes 4 and 5 show two orthogonal planes of motif that was constituted by phen/2,2′-bipy and indazole acid, respectively. The intermolecular interactions including hydrogen bonding and π-π stacking interactions are stabilizing these complexes. The interactions of the synthesized complexes with calf-thymus DNA (CT-DNA) have been investigated by UV-vis absorption titration, ethidium bromide displacement assay and viscosity measurements. The results reveal that the complexes could interact with CT-DNA via a groove binding mode. Their behavior rationalization was further theoretically studied by molecular docking.     

Two cadmium(II) addition compounds with 3-hydroxy-2,7-naphthalenedisulfonate containing aromatic diamines and their 3-D net

{[CdCl(2,2′-bipy)₂(H₂O)]⁺·[Cd(3-O^?-2,7-NDS)(2,2′-bipy)₂]^?·3H₂O} (1) and {[Cd(phen)₃]²⁺·2[Cd(3-O^?-2,7-NDS)(phen)₂]^?·8.5H₂O} (2) (3-OH-2,7-NDS?=?3-hydroxy-2,7-naphthalenedisulfonate, phen?=?1,10-phenanthroline, and 2,2′-bipy?=?2,2′-bipydine) were prepared and characterized by X-ray single-crystal diffraction. Compound 1 contains a discrete coordination cation [CdCl(2,2′-bipy)₂(H₂O)]⁺ and a coordination anion [Cd(3-O^?-2,7-NDS)(2,2′-bipy)₂]^?; 2 contains a discrete coordination cation [Cd(phen)₃]²⁺ and two coordination anions [Cd(3-O^?-2,7-NDS)(phen)₂]^?. There are numerous weak interactions among the coordination cation, coordination anion, and free water molecules, such as O–H?···?O hydrogen bonds, π?···?π stacking, and Cl^??···?π interactions in 1 and π?···?π stacking and C–H?···?π interactions in 2. The cations and anions as building blocks are connected to construct different 3-D supramolecular architectures via weak intermolecular interactions. Particularly, the capsule structure of 1 was observed.     

Syntheses and characterization of three mercury(II) complexes, [Hg(phen)2(SCN)2], [Hg(2,2′-bipy)2(SCN)2] and [Hg(phen)2(NO3)2], thermal and fluorescence studies

Mercury(II) complexes of 1,10-phenanthroline (phen) and 2,2′-bipyridine (bipy), [Hg(phen)₂(SCN)₂] (1), [Hg(2,2′-bipy)₂(SCN)₂] (2) and [Hg(phen)₂(NO₃)₂] (3) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The thermal stability of 1–3 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The structure of 1 has been confirmed by X-ray crystallography. The complex is a monomer and the Hg atom has an unsymmetrical six-coordinate geometry, formed by four nitrogen atoms of the two phen ligands and two sulfur atoms of the two thiocyanate anions. Solid-state luminescent spectra of phen, 2,2′-bipy and 1–3 indicate emission with the maximum intensity at ca 467 nm upon excitation at 295 nm.     

The assembly of POM-induced inorganic–organic hybrids based on copper ions and mixed ligands

Three inorganic–organic hybrid materials based on Keggin-type polyoxometalates (POMs), [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂][PMo₁₂O₄₀]₂·2H₂O (1), [Cu^II(phen)₂(H4,4′bipy)][PW₁₂O₄₀]·H₂O (2), and [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂](H₂4,4′-bipy)_0.5·3H₂O (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), were synthesized using different POMs in the hydrothermal conditions. Compounds 1–3 were characterized by single-crystal X-ray diffraction, IR spectra, elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Compound 1 presents a two-dimensional (2-D) network containing the Keggin-type [PMo₁₂O₄₀]^3? anion and dinuclear metal–organic units [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂]³⁺. Compound 2 is a 2-D architecture constructed from a [PW₁₂O₄₀]^3? and mononuclear metal–organic units [Cu^II(phen)₂(H4,4′-bipy)]³⁺. In 3, the [BW₁₂O₄₀]^5? anions link [Cu^II₂(phen)₂(4,4′-bipy)] units to form a one-dimensional (1-D) chain [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂]; the 1-D chain connects with protonated 4,4′-bipy ligands and lattice waters, yielding a 2-D layer. Fluorescence spectra, UV–vis spectra, and electrochemical properties of 1–3 have been investigated.     

Four anthraquinone-1,5-disulfonate-based metal complexes incorporating N-heterocyclic coligands: synthesis,crystal structures,and fluorescence

Four new anthraquinone-1,5-disulfonate (L)-based metal complexes with N,N-bidentate chelating coligands, {[Pb(phen)₂(L)]?·?4H₂O} _n (1), {[Mn₂(2,2′-bipy)₂(H₂O)₆(L)]?·?L?·?6H₂O} (2), [Co(phen)₂(H₂O)(L)] (3), and [Zn(phen)₂(H₂O)(L)] (4) (phen = 1,10-phenanthroline and 2,2′-bipy?=?2,2′-bipyridine), have been hydrothermally synthesized and were structurally characterized by single-crystal X-ray diffraction, elemental analyses, FT-IR spectra, thermogravimetric curves, and solid luminescence spectra. Structural analysis suggests that 1 is a polymeric 1D zigzag chain bridged by dianionic L. In contrast, the other three complexes have discrete centrosymmetric binuclear structure for 2 and isolated isomorphic mononuclear entities for 3 and 4, which are further assembled into 3D supramolecular networks by abundant hydrogen-bonding and/or π–π stacking interactions. Additionally, 2 and 4 exhibit favorable luminescent emissions, suggesting they are potential candidates for light emission materials.     

Positional isomeric and N-donor auxiliary chelating ligand effect on engineering crystalline architectures of four lead(II) complexes with diverse fluorescent properties

This work presents an investigation on the positions of the substituent and N-donor auxiliary chelating ligand (bipy/phen) effect on engineering of crystalline architectures of four Pb(II) complexes with a pair of methyl-substituted 3-sulfobenzoic isomers: [Pb(4-msba)(phen)(H₂O)] (1), [Pb(4-msba)(bipy)(H₂O)]·H₂O (2), [Pb(5-msba)(phen)₂]·9H₂O (3), and [Pb₂(5-msba)₂(bipy)₂(H₂O)₂] (4) (4/5-msba?=?4/5-methyl-3-sulfobenzoate, phen?=?1,10-phenanthroline and bipy?=?2,2′-bipyridine). The lead(II) ions exhibit hemidirected geometry in 1–4. The positions of the methyl as well as the auxiliary chelating ligands influence coordination modes of the sulfonates and thus determine the architectures. As the position of methyl in aromatic ring changes from 4 to 5, the structures change from 2-D sheet-like compounds for 1 and 2 to 0-D dimeric species for 3 and 4. A water cluster (H₂O)₁₈ exists in 3, which further assembles into a water tape with a new pattern T4(3)4(3)10(3)A4. Complex 3 loses crystallinity rapidly in the open air and turns into [Pb(5-msba)(phen)₂]·2H₂O (3A). Thermal stabilities and solid state fluorescent properties of 1, 2, 3A, and 4 have been studied.     

The construction of two lanthanide coordination polymers based on 5-hydroxyisophthalate and bipyridine

Two lanthanide coordination polymers, [Tm₂·(5-IPA)₄·(2,2′-Hbipy)₂]·3H₂O (1, 5-H₂IPA?=?5-hydroxyisophthalic acid, 2,2′-bipy?=?2,2′-bipyridine) and [Er·(5-HIPA)₃·(4,4′-bipy)₃·(H₂O)₂]·3H₂O (2, 4,4′-bipy?=?4,4′-bipyridine), have formed by hydrothermal synthesis. Complex 1 exhibits a 2-D coordination network containing parallelepiped-shaped voids occupied by guest 2′2-bipy molecules. Complex 2 possesses a 1-D linear chain structure. The 1-D chains are linked by 4,4′-bipy molecules to form a 3-D supramolecular framework. IR spectroscopy, elemental analysis, and thermogravimetric analysis were also investigated.     

Three coordination polymers built from planar tetranuclear clusters and 5-sulfoisophthalic acid

Three coordination polymers built from planar tetranuclear clusters and H₃sip ligands, Pb₂Cl(sip)(bipy) (1), Pb₂Br(sip)(H₂O) (2), and Ni₄(sip)₂(pyz)₂(H₂O)₈(OH)₂·2H₂O (3) (H₃sip?=?5-sulfoisophthalic acid, bipy?=?2,2′-bipyridine, and pyz?=?pyrazine), have been hydrothermally synthesized and characterized by IR, TGA, and single-crystal X-ray diffraction. Compound 1 features a 2-D layer-like structure containing tetranuclear square [Pb₄(SO₃)₂] clusters. Complex 2 has a 3-D open framework architecture constructed from tetranuclear cluster [Pb₄Br₂(SO₃)₂] inorganic building blocks. The tetranuclear units, [Ni₄(OH)₂(COO)₄], in 3 are interlinked through carboxylates and µ₂-pyz ligands to generate a 2-D layer structure. The connecting modes between tetranuclear clusters and organic ligands in the three compounds are discussed in this article. In the solid state at room temperature, yellow photoluminescence in 1 and 2 are observed.     

Synthesis,crystal structures,and characterization of copper(II) carboxylate complexes incorporating 1,10-phenanthroline and bipyridine

A series of Cu(II) carboxylate complexes (carboxylate?=?2-fluorobenzoic acid (2-HFBA) or 4-fluorobenzoic acid (4-HFBA)) containing either one chelating 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and thermal analyses. In [Cu(bipy)(H₂O)(2-FBA)₂] (1), [Cu(bipy)(H₂O)(4-FBA)₂] (3), and [Cu(phen)(H₂O)(2-FBA)₂] (4), Cu is five-coordinate in a square pyramidal geometry and four-coordinate in [Cu(phen)(2-FBA)₂] (2). The four complexes are extended into 1-D chains through hydrogen-bonding and π?···?π interactions in 1 and 4, only hydrogen-bonding in 2, and π?···?π interactions in 3. These contacts lead to aggregation and supramolecular self-assembly.     

Formation of [FeW12O40]5− under hydrothermal conditions: syntheses,crystal structures,and characterization of [Fe(2,2′-bipy)3]2[HFeW12O40] · 5H2O and (4,4′-H2bipy)6(Hpy)2(H3O)[FeW12O40]3 · 11H2O

Two supramolecular compounds based on tungstoferrate [FeW₁₂O₄₀]^5?, [Fe^II(2,2′-bipy)₃]₂[HFeW₁₂O₄₀] · 5H₂O (1), and [Hpy]₂[4,4′-H₂bipy]₆(H₃O)[FeW₁₂O₄₀]₃ · 11H₂O (2) (py = pyridine, bipy = bipyridine) were synthesized hydrothermally and characterized structurally. The hydrogen bonds between polyoxoanions and water and the edge-to-face π–π interaction between [Fe^II(2,2′-bipy)₃]²⁺ with a shortest C–C distance of 3.513 Å are the main forces to construct the 3-D architecture of 1. In 2, a 3-D supramolecular architecture is assembled by the tungstoferrate anions, protonated 4,4′-bipy cations, and water through hydrogen bonding. The variable-temperature magnetic susceptibilities indicate that 1 is paramagnetic with μ _eff corresponding to one Fe(III) with spin-only contribution, showing that Fe in the coordination cations has a +II oxidation number and low spin state.     

Complexes based on ferrocenecarboxylate ligands: steric hindrance induced by ferrocenyl groups

Three metal complexes with ferrocenecarboxylate ligands, [M₂(η ²-FcCOO)₂(μ₂-η ²-FcCONHCH₂COO)₂(phen)₂]?·?nH₂O [M?=?Pb, n?=?6 (1) and M?=?Cd, n?=?2 (2)] and [Cd(FcCONHCH₂COO)(μ₂-FcCONHCH₂COO)(2,2′-bipy)(H₂O)] _n (3) (FcCOOH?=?ferrocenemonocarboxylic acid, FcCONHCH₂COOH?=?N-ferrocenylformylglycine, phen?=?1,10-phenanthroline, 2,2′-biby?=?2,2′-bipyridine), were synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffraction analysis. Structural studies revealed that 1 and 2 have similar binuclear structures, but 3 exhibits a 1-D chain structure. The difference in the structures of ferrocenylcarboxylate-containing cadmium(II) complexes is due to steric hindrance of ferrocenyl groups.     

Synthesis and crystal structure of two praseodymium 2-iodobenzoic acid complexes

Two new complexes, {[Pr(2-IBA)₃?·?2,2′-bipy]₂·[Pr(2-IBA)₃?·?2,2′-bipy]₂?·?0.5C₂H₅OH?·?H₂O} (1) and [Pr(2-IBA)₃?·?phen]₂ (2) (2-IBA?=?2-iodobenzoate; 2,2′-bipy?=?2,2′-bipyridine; phen?=?1,10-phenanthroline) were synthesized, and their crystal structures were determined by X-ray diffraction. Complex 1 consists of two binuclear molecules [Pr(2-IBA)₃?·?2,2′-bipy]₂ (a) and [Pr(2-IBA)₃?·?2,2′-bipy]₂ (b), half uncoordinated ethanol and one uncoordinated water. In the two molecules (a) and (b), the coordination environment of central ions is similar. The Pr1³⁺ ion in molecule (a) and Pr2³⁺ ion in molecule (b) are nine-coordinate with seven oxygen atoms from five 2-IBA ligands and two nitrogen atoms from one 2,2′-bipy molecule. The crystal structure of complex 2 is similar to that of binuclear [Pr(2-IBA)₃?·?2,2′-bipy]₂ in complex 1.     

Synthesis,characterization, and crystal structures of two Ag (I) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate

In this article, [Ag₈(btc)₂(2,2′-bpy)₂] _n (1) and [Ag₄(btc)(phen)₂] _n (2) (H₄btc?=?biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine, phen?=?1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 shows a 3-D framework containing a 2-D bilayer network constructed from (btc)^4? with Ag (I), whereas 2 features a 2-D supramolecular bilayer network. The differences of the two complexes demonstrate that nitrogen-containing chelating ligands have a significant effect on the formation and structure of the resulting complexes. Electrochemistry properties of 1 were also studied.     

Syntheses and crystal structures of two lead complexes containing tricyanomethanide

Two lead complexes [Pb(2,2′-bipy)₂(H₂O)₂(tcm)]₂·(tcm)₂·2H₂O, 1, and [Pb(phen)₂(tcm)₂], 2, have been prepared by reacting Pb(NO₃)₂, potassium tricyanomethanide (Ktcm) and 2,2-bipyridine or 10-phenanthroline, respectively. X-ray crystallography studies show that 1 is a dimer formed by two eight-coordinate [Pb(bipy)₂(H₂O)₂] units bridged by tricyanomethanide while 2 is a mononuclear six-coordinate compound with the lead atom surrounded by two phen ligands and two tricyanomethanide ions.     

Synthesis,characterization and crystal structures of Ni(II), Cd(II) complexes with N -(2-propionic acid)-salicyloyl hydrazone and bipy/phen

The ligand N-(2-propionic acid)-salicyloyl hydrazone(H₃L, 1) and its new transition metal(II) complexes [NiHL(bipy)H₂O] (2), [CdHL(bipy)(H₂O)₂]₂·2H₂O (3) and [NiHL(phen)H₂O]·H₂O (4) (HL is a dianion, bipy?=?2,2′-bipyridine and phen?=?1,10-phenanthroline) were synthesized and characterized on the basis of elemental analyses, IR, ¹H NMR, molar conductivity and thermal analysis. Single crystal X-ray diffraction showed that 1 is in keto form and connected by hydrogen bonds to form a two-dimensional supermolecular compound. Complexes 2 and 4 have the same structure with distorted meridional octahedral geometry with 1 as a tridentate ligand with keto-form coordination by azomethine, carboxyl O and acyl O. In 3, ligand 1 bridges two Cd(II) atoms by μ ₂-O of carboxyl. H-bonding is an important weak interaction for constructing supermolecular frameworks. There are π–π interactions between bipy or phen rings in 3 or 4, respectively.     

Syntheses,structures, and properties of four coordination compounds constructed from asymmetric semi-rigid V-shaped multicarboxylate ligand

Four new compounds, [Mn(HL)(phen)₂(H₂O)] (1), [Ni(HL)(phen)₂(H₂O)] (2), [Zn(HL)(4,4′-bipy)_1.5(H₂O)] _n ?·?2nH₂O (3) and [Zn₂(HL)₂(H₂O)₆] (4), have been synthesized from an asymmetric semi-rigid V-shaped multicarboxylate 4-(4-carboxy-phenoxy)-phthalic acid (H₃L) with 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy) as auxiliary ligands. Single-crystal X-ray diffraction analysis reveals that 1, 2 and 4 have 0-D structures with 3-D supramolecular frameworks formed by intermolecular hydrogen bonds. Compound 3 shows a 1-D infinite ribbon bridged by 4,4′-bipy, which further forms a 3-D supramolecular architecture by π–π stacking interactions and hydrogen bonds. Thermal stabilities of 1–4 and luminescence properties of 3 and 4 have also been investigated.     

Design,synthesis and magnetic properties of a ladderlike complex constructed by secondary building units

A secondary building unit (SBU), [Ni(2,2′-bipy)(5-npa)(H₂O)] _n [where 2,2′-bipy = 2,2′-bipyridine, 5-npa = 5-nitroisophthalic dianion], was synthesized as starting material of a polystep reaction. A ladderlike complex (LLC) Ni(II) coordination polymer, {[Ni(2,2′-bipy)(5-npa)(4,4′bipy)_0.5]·(H₂O)} _n , was constructed by polystep reaction using this SBU. In LLC, two SBUs were cross-linked by 4,4′-bipy [where 4,4′-bipy = 4,4′-bipyridine] forming a 1-D ladderlike structure. The magnetic properties of the LLC and SBU are discussed.     

Synthesis,crystal structures,and fluorescence properties of (RS)-2-methylglutarato Zn(II), Cd(II) complexes

Reactions of fresh M(OH)₂ (M = Zn²⁺, Cd²⁺) precipitate and (RS)-2-methylglutaric acid (H₂MGL), 2,2′-bipyridine (bipy), or 1,10-phenanthroline (phen) in aqueous solution at 50°C afforded four new metal–organic complexes [Zn₂(bipy)₂(H₂O)₂(MGL)₂] (1), [Zn₂(phen)₂(H₂O)(MGL)₂] (2), [Cd(bipy)(H₂O)(MGL)] · 3H₂O (3), and [Cd(phen)(H₂O)(MGL)] · 2H₂O (4), which were characterized by single crystal X-ray diffraction, IR spectra, TG/DTA analysis as well as fluorescence spectra. In 1, the [Zn(bipy)(H₂O)]²⁺ moieties are linked by R- and S-2-methylglutarate anions to build up the centrosymmetric dinuclear [Zn₂(bipy)₂(H₂O)₂(MGL)₂] molecules. In 2, the 1-D ribbon-like chains [Zn₂(phen)₂(H₂O)(MGL)₂] _n can be visualized as from centrosymmetric dinuclear [Zn₂(phen)₂(H₂O)₂(MGL)₂] units sharing common aqua ligands. Both 3 and 4 exhibit 1-D chains resulting from [Cd(bipy)(H₂O)]²⁺ and [Cd(phen)(H₂O)]²⁺, respectively, bridged alternately by R- and S-2-methylglutarate anions in bis-chelating fashion. The intermolecular and interchain π···π stacking interactions form supramolecular assemblies in 1 and 1-D chains in 2–4 into 2-D layers. The hydrogen bonded lattice H₂O molecules are sandwiched between 2-D layers in 3 and 4. Fluorescence spectra of 1–4 exhibit LLCT π → π* transitions.     

A series of new oxo-vanadium(IV) complexes with octahedral coordinated vanadium centers

A series of new oxo-vanadium(IV) complexes, [VOCl0.69(OH)0.31 (2,2′-bipy)2]Cl·2H2O (1, 2,2′-bipy?=?2,2′-bipyridine) [(VO)₂Cl₄(4,4'-bipy)₃ (H₂O)₂] (2, 4,4'-bipy?=?4,4'-bipyridine), [VO(ida)(H₂O)]_n (3, H₂ida?=?iminodiacetic acid), and [(VO)₂(oa)₄]_n·4n(H₃O)·n(H₂O) (4, H₂oa?=?oxalic acid), have been synthesized and structurally characterized. 1 contains a [VOCl_0.69(OH)_0.31(2,2′-bipy)₂]⁺ cation, Cl ^– anion and two free H₂O molecules. 2 exhibits a binuclear centrosymmetric moiety built up from two [VOCl₂(4,4'-bipy)(H₂O)] units and one bridging 4,4'-bipy ligand, which provides a rare example of a 4,4'-bipy molecule acting as monodentate ligand. 3 displays a neutral chain [VO(ida)(H₂O)]_n constructed by the linkages of [VO(H₂O)]²⁺ units and ida^2? bridging ligands, while 4 offers the only example of three kinds of oa^2- ligands coexisting within the same anionic chain [(VO)₂(oa)₄^4-]_n. Their spectroscopic properties were investigated, and the magnetic susceptibility of 4 shows antiferromagnetic behavior.     

Two zinc(II) complexes based on indole-3-acetic acid: crystal structures,fluorescence sensors,and ion exchange with mercury(II)

Two new coordination complexes, [Zn(IA)₂(phen)] (1) and [Zn(IA)₂(4,4′-bipy)] _n ?·?C₂H₅OH (2) (IAH?=?indole-3-acetic acid, phen?=?1,10-phenanthroline, 4,4′-bipy?=?4,4′-bipyridine), have been prepared and characterized by single-crystal X-ray diffraction. Complex 1 is mononuclear and 2 presents a 1-D zigzag chain, in which 4,4′-bipy connects the Zn(II) ions. Both complexes show fluorescence emissions and exhibit fluorescence quenching when Hg²⁺ ions are present. ICP, EDS, and SEM experiments reveal that zinc in both complexes can be exchanged by toxic mercury ions.