Nicotinic Acid Ligands Research Articles

Two new coordination polymers of Tl(I) & Hg(II), based on nicotinic acid ligand: synthesis, characterization, crystal structure determination & DFT calculation

Two new coordination polymers of Tl(I) & Hg(II), based on nicotinic acid ligand: synthesis, characterization, crystal structure determination & DFT calculation

Synthesis, structure, fluorescence and magnetic studies of two oxygen bridged polycarboxylic acid ligands and rare earth metal ion Pr, Gd, and Er complexes

In order to further enrich the research on the synthesis of complexes with polycarboxylic acid ligands and rare earth metal ion. In this study, four rare earth complexes, namely, [Gd(cpia)]n (1), [Er(cpia)]n (2), [Pr(cpna)2·2H2O]n (3) and [Gd(Hcpna)(cpna)•3H2O]n (4) have been synthesized by solvothermal method based on 5-(2-carboxyphenoxy)isophthalic acid (H3cpia) and 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna) with rare earth metal ions Pr3+, Gd3+ and Er3+. Single crystal X-ray diffraction analyses reveal that complexes 1, 2 and 3 are two-dimensional network structure, 4 is one-dimensional chain structures. The fluorescence test results show that the fluorescence intensity of complexes 1 and 2 were lower than that of the H3cpia ligand, the fluorescence intensity of complexes 3 and 4 were lower than that of the H2cpna ligand. Magnetic results indicate complex 1 has ferromagentic behavior and weak antiferromagentic behavior in the complexes 2, 3 and 4.

Synthesis, optical and magnetic study of nicotinic acid ligand lanthanum, neodymium and terbium complexes

In this work, three rare earth complexes, namely, [La(cpna)2·2H2O]n (1), [Nd(Hcpna)(cpna)•3H2O]n (2) and [Tb(Hcpna)(cpna)•3H2O]n (3) have been synthesized by solvothermal method based on 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna) and rare earth metal ions La3+, Nd3+ and Tb3+. Single crystal X-ray diffraction analyses reveal that complex 1 is a two-dimensional network structure, 2 and 3 are isostructural complexes, and the structures are all one-dimensional chain structures. The fluorescent test results show that the complex 3 has excellent fluorescence properties, and can emit bright green light under the irradiation of the ultraviolet lamp at 365 nm. Magnetic results indicate weak antiferromagentic interactions in the complex 2 and 3.

Synthesis, optical and magnetic research of nicotinic acid ligand Zn, Cd, Mn and Co complexes

In this study, a multiple binding sites ligand, 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna), was used to construct metal complexes with Zn2+, Cd2+, Mn2+ and Co2+ by solvothermal reaction, and four new complexes were constructed, namely, [Zn (cpna)•H2O]n (1)，[Cd (cpna) (CH3CN)·2H2O]n (2), [Mn (cpna)•2H2O]n (3) and Co(cpna)•2H2O]n (4); All the complexes were characterized by single crystal X-ray diffraction, elemental analysis and infrared analysis in the solid state; Single crystal x-ray diffraction analyses reveal that complexes 1 and 2 have two-dimensional network structures, complexes 3 and 4 have three-dimensional structures. In addition, Luminescence behavior of complex 1 and 2 was investigated and magnetic properties of complex 3 and 4 were studied. The fluorescent test results show that the fluorescence intensity of complex 1 is higher than that of ligand and emission band can be considered as LLCT emission of ligand; The Magnetic results indicate weak ferromagentic interactions in complex 3 and χmT value rises slowly and then decreases sharply from 300 ​K to 2 ​K. However, magnetic results indicate antiferromagentic interactions in complex 4 and χmT value can be divided into three parts with the change of temperature from 300 ​K to 2 ​K.

Raman spectra of copper, cobalt, and nickel complexes of nicotinic acid: Equilibrium studies

This article summarizes the protonation and complexation equilibrium constants of nicotinic acid (NA) using different analytical techniques and software’s. Additionally, Raman, IR, and NMR spectra were done for nicotinic acid ligand and for its solid complexes with copper(II), cobalt(II) and nickel(II) metal ions. KEY WORDS: Nicotinic acid, Potentiometry, Spectrometry, Equilibrium constants Bull. Chem. Soc. Ethiop. 2018, 32(3), 459-467.DOI: https://dx.doi.org/10.4314/bcse.v32i3.5

Three Polyoxometalate‐Based Coordination Polymers Constructed from the Same Dimetallic Cyclic Building Block

The reactions of silicotungstate, 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo), and copper, cobalt, or nickel acetate under hydrothermal condition yield the three compounds [(SiW12O40)Cu2(3-bpo)2(C5H4NCOOH)2]·H2O (1), [(SiW12O40)Co2(3-bpo)2(C5H4NCOOH)2(H2O)2]·2H2O (2), and [(SiW12O40)Ni2(3-bpo)2(C5H4NCOOH)2(H2O)2]·3H2O (3), respectively, in which the nicotinic acid ligands are generated from the in situ decomposition of 3-bpo during the hydrothermal process. In the three structures, the polyoxometalate (POM) serves as the center and is imbedded within the dimetallic cyclic [M2(3-bpo)2(C5H4NCOOH)2]4+ moiety through coordination bonds to form infinite one-dimensional (1D) supramolecular snadwich-like structures. Owing to the difference in the metal ions, the packing style of [Cu2(3-bpo)2(C5H4NCOOH)2]4+ is different from that of [M2(3-bpo)2(C5H4NCOOH)2]4+ (M = Co, Ni). The electrochemical behaviors of compounds 1–3 were studied by cyclic voltammetry.

Hydrothermal synthesis, structure, and optical properties of two nanosized Ln26 @CO3 (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs).

Two Ln26 @CO3 (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs) formulated as [Dy26 Cu3 (Nic)24 (CH3 COO)8 (CO3 )11 (OH)26 (H2 O)14 ]Cl ⋅3 H2 O (1; HNic=nicotinic acid) and [Tb26 NaAg3 (Nic)27 (CH3 COO)6 (CO3 )11 (OH)26 Cl(H2 O)15 ]⋅7.5 H2 O (2) have been successfully synthesized by hydrothermal methods and characterized by IR, thermogravimetric analysis (TGA), elemental analysis, and single X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a=35.775(12) Å, b=33.346(11) Å, c=24.424(8) Å, β=93.993(5)°, V=29065(16) Å(3) , whereas 2 crystallizes in the triclinic space group P$\bar 1$ with a=20.4929(19) Å, b=24.671(2) Å, c=29.727(3) Å, α=81.9990(10)°, β=88.0830(10)°, γ=89.9940(10)°, V=14875(2) Å(3) . Structural analysis indicates the framework of 1 is a 3D perovskite-like structure constructed out of CO3 @Dy26 building units and Cu(+) centers by means of nicotinic acid ligand bridging. In 2, however, nanosized CO3 @Tb26 units and [Ag3 Cl](2+) centers are connected by Nic(-) bridges to give rise to a 2D structure. It is worth mentioning that this kind of 4d-4f cluster-based MOF is quite rare as most of the reported analogous compounds are 3d-4f ones. Additionally, the solid-state emission spectra of pure compound 2 at room temperature suggest an efficient energy transfer from the ligand Nic(-) to Tb(3+) ions, which we called the "antenna effect". Compound 2 shows a good two-photon absorption (TPA) with a TPA coefficient of 0.06947 cm GM(-1) (1 GM=10(-50) cm(4) s photon(-1) ), which indicates that compound 2 might be a good choice for third-order nonlinear optical materials.

Synthesis, crystal structures and properties of novel heterobimetallic Cd–Pt and Zn–Pt coordination polymers using nicotinic acid

Two novel heterobimetallic coordination polymers, [Cd{Pt(nic) 4 }] n ・5nH 2 O ( Cd–Pt-1 ) and [Zn{Pt(nic) 4 }(H 2 O) 4 ] n ・nH 2 O ( Zn–Pt-1 ) (nicH = nicotinic acid), were synthesized by a one-pot slow-evaporation reaction system in water. Single crystal X-ray analysis revealed that Cd–Pt-1 and Zn–Pt-1 are two-dimensional sheet frameworks with open pores and one-dimensional chain polymers, respectively. However, crystal structure of Cd–Pt-1 is not robust in air. Therefore, BET surface area (pore volume) of Cd–Pt-1 calculated by N 2 gas adsorption measurement is very low and the value is 22.5 m 2 g − 1 (0.00813 cm 3 g − 1 ). Two novel heterobimetallic coordination polymers, [Cd{Pt(nic) 4 }] n ・5nH 2 O ( Cd–Pt-1 ) and [Zn{Pt(nic) 4 }(H 2 O) 4 ] n ・nH 2 O ( Zn–Pt-1 ) (nicH = nicotinic acid), were synthesized by a one-pot slow-evaporation reaction system in water. Single crystal X-ray analysis revealed that Cd–Pt-1 and Zn–Pt-1 are two-dimensional sheet frameworks and one-dimensional chain polymers, respectively. Although crystal structure of Cd–Pt-1 has open pores for N 2 or H 2 gas adsorption, they are closed due to the loss of crystal structure by removal of guest molecules. ► Two types of Cd–Pt and Zn–Pt coordination polymers with nicotinic acid ligand were synthesized and identified. ► Crystal structure of Cd–Pt coordination polymer is two dimensional sheet framework. ► Crystal structure of Zn–Pt coordination polymer is one-dimensional zig–zag chain structure. ► N 2 and H 2 gas adsorption properties of two Pt coordination polymers were investigated.

Synthesis, crystal structure and properties of Zn(II) and Cd(II) complexes with 2-(4-isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)nicotinic acid ligand

Abstract Two novel complexes, namely [Cd(L)2] (1) and [Zn(L)2(H2O)2] (2) have been synthesized (HL = 2-(4-isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)nicotinic acid), which are characterized by elemental analysis, infrared spectrum and X-ray crystal diffraction. While strong hydrogen bonds play central roles in the formation of the 3D structure, the combined influence of the weak interactions such as C–H⋯O bonds, carbonyl⋯π and C–H⋯π interactions are also evident in the structures. The preliminary investigation on the thermal and fluorescence property of the complexes are presented.

Ligand-Dependent Ultrasonic-Assistant Self-Assemblies and Photophysical Properties of Lanthanide Nicotinic/Isonicotinic Complexes

Two structural series, including two isomorphous homodinuclear complexes Ln(2)(H(2)O)(4)(C(6)NO(2)H(4))(6) (Ln = Tb (1) and Er (2)) and four isostructural one-dimensional (1-D) chain-like assemblies [Ln(H(2)O)(4)(C(6)NO(2)H(4))(2)](n) x nCl (Ln = Sm (3), Eu (4), Tb (5), and Dy (6)), have been rationally prepared through a facile ultrasonic synthesis and have been characterized by X-ray diffraction and photophysical measurements. Both complexes, 1 and 2, feature a homodinuclear structure, based on two 8-fold coordination lanthanide atoms bridged by four nicotinic acid ligands. Complexes 3-6 are characterized by a 1-D polycationic chain-like structure, containing eight-coordinated lanthanide ions and bridging isonicotinic acid ligands. The 1-D polycationic chains and the isolated chloride anions are interconnected via hydrogen bonds and pi-pi interactions to form a three-dimensional supramolecular network. The effect of nicotinic/isonicotinic acid ligands on the structures and the photoluminescence properties, as well as the relationship between the photoluminescence properties and the structures, was investigated based on IR, UV-vis absorption spectra, low temperature phosphorescent spectra, excitation, and emission spectra. The fluorescence quantum yields of complexes 1 and 2 were determined to be 44% and 21%, respectively.

A novel three-dimensional copper(I) coordination polymer constructed from a copper–bromide net and nicotinic acid ligands

The title compound, poly[mu(3)-bromido-(pyridine-3-carboxylato-kappaN)copper(I)], [CuBr(C(6)H(5)NO(2))](n), is a novel coordination polymer based on a copper-bromide net and nicotinic acid ligands. The asymmetric unit contains one copper(I) ion, one bromide ligand and one nicotinic acid ligand, all on general positions. The Cu(I) atom is tetrahedral and coordinated by three bridging Br atoms and the N atom from the nicotinic acid ligand. The Cu-Br units form alternating six-membered chair-patterned rings in net-like layers. The attached nicotinic acid units point alternately up and down. The layers are assembled into a three-dimensional network via intermolecular O-H...O and C-H...Br hydrogen-bonding interactions.

Self-assembly of a 3D supramolecular architecture with nicotinic acid ligands and polyoxomolybdate units

A new polyoxomolybdates supramolecular architecture with nicotinic acid ligands, (Himi) 4[(nic- O) 2(Mo 8O 26)] ( 1) (imi=imidazole, nic- O=nicotinic acid), has been prepared by hydrothermal synthesis and characterized by single crystal X-ray diffraction, IR, XPS spectra, and thermogravimetric analysis. The structure of 1 consists of nicotinic acid-coordinated γ-{Mo 8O 26} 4− anions and protonated imidazole cations resulting in the formation of a 3D framework based on hydrogen bonding contacts between protonated imidazole cations and [(nic- O) 2Mo 8O 26] 4− anions.

Catena-Poly[[[mu-pyridinium-3-carboxylato-bis[dioxomolybdenum(VI)]]-di-mu3-oxo] monohydrate

A novel chain molybdenum compound, [[Mo2O6(C6H5NO2)].H2O]n, which was synthesized under hydrothermal conditions, consists of an infinite rail-like chain formed by molybdenum oxide units linked by zwitterionic nicotinic acid ligands. Each Mo atom is coordinated octahedrally by six O atoms and the MoO6 octahedra are linked to one another via edge-sharing to produce a zigzag polymeric chain, with nicotinic acid ligands located, alternately, on each side of the rail-like chain plane.

The structure of Escherichia coli nitroreductase complexed with nicotinic acid: three crystal forms at 1.7 Å, 1.8 Å and 2.4 Å resolution

Escherichia coli nitroreductase is a flavoprotein that reduces a variety of quinone and nitroaromatic substrates. Its ability to convert relatively non-toxic prodrugs such as CB1954 (5-{aziridin-1-yl}-2,4-dinitrobenzamide) into highly cytotoxic derivatives has led to interest in its potential for cancer gene therapy. We have determined the structure of the enzyme bound to a substrate analogue, nicotinic acid, from three crystal forms at resolutions of 1.7 Å, 1.8 Å and 2.4 Å, representing ten non-crystallographically related monomers. The enzyme is dimeric, and has a large hydrophobic core; each half of the molecule consists of a five-stranded β-sheet surrounded by α-helices. Helices E and F protrude from the core region of each monomer. There is an extensive dimer interface, and the 15 C-terminal residues extend around the opposing monomer, contributing the fifth β-strand. The active sites lie on opposite sides of the molecule, in solvent-exposed clefts at the dimer interface. The FMN forms hydrogen bonds to one monomer and hydrophobic contacts to both; its si face is buried. The nicotinic acid stacks between the re face of the FMN and Phe124 in helix F, with only one hydrogen bond to the protein. If the nicotinamide ring of the coenzyme NAD(P)H were in the same position as that of the nicotinic acid ligand, its C4 atom would be optimally positioned for direct hydride transfer to flavin N5. Comparison of the structure with unliganded flavin reductase and NTR suggests reduced mobility of helices E and F upon ligand binding. Analysis of the structure explains the broad substrate specificity of the enzyme, and provides the basis for rational design of novel prodrugs and for site-directed mutagenesis for improved enzyme activity.

Pitfalls in the supramolecular assembly of silver(I) coordination compounds

The syntheses and crystal structures of (6-methylnicotinic acid) (6- methylnicotinato)silver(I), di (6-methylnicotinic acid) silver(I) nitrate, (2-chloro-6-methylnicotinato) silver(I), di (2-chloro-6-methylnicotinic acid) silver(I) nitrate, and (2-methylni-cotinic acid) (2-methylnicotinato) silver(I) are described. These coordination complexes were synthesized under the same conditions and with very similar ligands but their resulting structures are quite different, in part due to the degree of protonation of the nicotinic acid ligand(s). The structures vary from coordination polymers to hydrogen-bonded coordination dimers, to linear structures linked by anion-carboxylic acid hydrogen bonds. This study illustrates some of the difficulties involved in predicting hydrogen-bonded networks in transition-metal systems which contain carboxylic acid moieties and coordinatively unsaturated metal ions.

Structure and biological activity of nitrogen and oxygen coordinated nicotinic acid complexes of chromium

A series of N-coordinated M(II)(nic) 2(H 2O) 4 ≠ complexes, where M = Co, Ni, Mn or Cr and the O-coordinated species Cr(III)(nic) 2(H 2O) 4 + and Cr(III)(nic)(H 2O) 5 +2 have been prepared. A single crystal X-ray analysis of the complex Cr(II)(nic) 2(H 2O) 4 shows that the chromium ion is in the +2 oxidation state and that two nicotinic acid ligands are coordinated in a trans arrangement via the pyridine ring nitrogen atoms. The four equatorial positions are occupied by water molecules. Biological activity measurements with a yeast bioassay system however show that none of the N-coordinated complexes possess any glucose tolerance factor (GTF-type) activity. On the other hand, the O-coordinated chromium(III)-dinicotinic acid complex is biologically active which suggests that a trans arrangement of pyridine nitrogen atoms resembles that part of the GTF structure which is recognised by the receptors or enzymes which are involved in the expression of the biological effect.

Synthesis and characterization of divalent manganese, cobalt, nickel, copper and zinc complexes with nicotinic acid

Coordination compounds of the transition metal(II) acetylacetonates of the formula [M(NA) 2(acac) 2 ] n (M = Mn, Co, Ni, Cu and Zn; NA = nicotinic acid and acac = acetyl-acetonate anion) have been synthesized and characterized by chemical analysis, magnetic susceptibility, ligand-field spectra, IR and far-IR spectral measurements as well as photoacoustic spectroscopy in the solid state. Tentative stereochemistries for the complexes isolated in the solid state are suggested. The ligand-field parameters 10 Dq, B, β, λ and CFSE are calculated for cobalt and nickel complexes and are in good agreement with the proposed geometries. The metal ions attain six-coordination through the four oxygens of the anion and two donor atoms of the nicotinic acid ligands acting always as monodentate ligands. The formation of the compound results in a considerable shift of v(M-O) to lower frequencies in all the compounds related to parent acetylacetonates.