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Two new lanthanide-mercury complexes [Eu(HIA)2(H2O)2Hg2Cl5(IA)]nn(HgCl2)·2nH2O·nCl (1) and [Tb(HIA)2(H2O)2Hg2Cl5(IA)]nn(HgCl2)·2nH2O·nCl (2) (HIA = isonicotinic acid) have been prepared through hydrothermal reactions and structurally determined by single crystal X-ray diffraction. 1 and 2 are isostructural and have a two-dimensional (2-D) layer structure. Solid-state UV/Vis diffuse reflectance spectroscopy shows that there is a wide optical band gap of 3.42 and 3.44 eV for 1 and 2. Photoluminescence measurement of solid-state samples revealed that 1 and 2 exhibit red or green emission, respectively. The photoluminescence bands originate from the characteristic 4f-electron intrashell transitions of 5D1 → 7F1 and 5D0 → 7FJ (J = 1, 2 and 4) (Eu3+: J = 1, 2, 4) for 1, and 5D4 → 7FJ (Tb3+: J = 3, 4, 5, 6) for 2. Energy transfer mechanism is explained by the energy level diagram of the Eu3+ and Tb3+ ions and of the isonicotinic acid ligand. The complexes have CIE chromaticity coordinates of (0.59, 0.35) and (0.29, 0.48) for 1 and 2, respectively.

Solvothermal reactions of isonicotinic acid (HIN) with lanthanide nitrate and cuprous halide yielded seven three-dimensional (3D) 3d-4f heterometallic coordination polymers (HCPs). These HCPs are formulated as {[NH 2 (CH 3 ) 2 ] 2 LnCu 2 Br(IN) 6 ∙(DMA) 2 } n (Ln = Sm( 1 ), Eu( 2 ), Gd( 3 ), Tb( 4 ), Dy( 5 )) and [LnCu(IN) 4 ∙DMA] n (Ln = Er( 6 ), Yb( 7 )). Compounds 1 – 5 possess anionic three-dimensional pillared-layer frameworks with pcu topology, while compounds 6 – 7 show a rare 3d-4f dia -type two-fold interpenetrating framework with one dimensional square channels with side length of about 9.0 A along the a axis. Crystal structure analysis reveals that the structure diversity is attributed to the synergistic effect of lanthanide contraction and halide anions. In addition, the magnetic properties of 1 , 3 , 4 and 5 were investigated.

Two Co-based metal organic frameworks (MOFs), namely, {Co(Hin)2}n·DMF (1) and {Co2(Hin)4}n (2) (Hin = isonicotinic acid), are solvothermally synthesized from the reaction of isonicotinic acid and cobalt chloride under different pH conditions. Interestingly, both complexes are constructed under acidic conditions, and complex 2 can be fabricated at a lower pH value. Both complexes are characterized by IR spectroscopy, elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The single crystal X-ray diffraction studies indicate that complex 1 and complex 2 are three-dimensional frameworks. The antibacterial activities of complex 1 and complex 2 are investigated by determining their minimal inhibitory concentration (MIC) values against gram-positive bacteria (Staphylococcus. aureus) and gram-negative bacteria (Escherichia. coli), which are bacteria commonly encountered in our daily environments. The results reveal that both complexes are more sensitive to S. aureus than to E. coli. Furthermore, the dye adsorption capacities of complex 1 and complex 2 are investigated. The common organic dyes Congo red and Orange IV are chosen to be absorbed by the title complexes. The results show that both complex 1 and complex 2 have strong absorption capacities toward Orange IV within a short time.

To integrate the respective advantages exhibited by half-sandwich arene-Ru(II) fragments and 5-FU derivatives, a multifunctional ligand that links isonicotinic acid and 5-Fu (5-fluorouracil) through an ester bond for achieving the enhanced effect and an organoruthenium(II) complex containing this ligand were prepared and characterized by standard analytical techniques. The cytotoxicity of these organoruthenium(II) compounds containing 5-fluorouracil-1-methyl isonicotinate against BEL-7402 human cancer cells was moderately improved, which implies synergistic action of 5-Fu and the half-sandwich-structured arene-Ru(II). In addition, the organoruthenium(II) compounds containing isonicotinic acid and methyl isonicotinate are also discussed, and the crystal structure of [(η6-p-cymene)RuCl2(methyl isonicotinate)] (4) was determined; its piano-stool structure is analyzed in this paper.

Spectroscopic speciation of U(VI) solutions holding pyridine carboxylic acid N-oxides in a range pH 2.3–4.5 results in the single component spectrum of the U(VI) isonicotinic acid N-oxide complex. The molar absorption is 14 ± 2 L mol−1 cm−1 at 415.4 nm. The formation constant lg KUL = 2.1 ± 0.2 (k = 2) is derived from solution modelling and by multivariate chemometric analysis. The first crystal structure analysis of a U(VI) pyridine carboxylic acid N-oxide revealed a sheet-like structure where the isonicotinic acid N-oxide binds to the uranyl(VI) both bidentately by the carboxylate group and monodentately by the N–O group. The single component spectrum of the [UO2L]+ (where L− is isonicotinate N-oxide) is compared to the small number of other U(VI) single ligand species. The comparison revealed the possible pitfalls of U(VI) spectroscopic speciation close to the pH region where U(VI) hydrolysis starts to interfere. On basis of the results for U(VI)–L coordination and physicochemical properties of the pyridine carboxylic acid N-oxides some conclusions could be drawn on the likely behaviour of nicotinic acid N-oxide and picolinic acid N-oxide. For the former, complex formation in a narrow range of pH and U(VI) concentrations close to the hydrolysis range of U(VI) might reveal thermodynamic data. In the case of picolinic acid N-oxide, additional experimental evidence is required to characterize suitable conditions.

Two 3d/5d–4f metal complexes [DyL3(H2O)2]n(1.5nHgCl4) · 2nH2O (1) and [ EuL ′ 3 ( H 2 O ) 2 ] n (1.5nZnCl4) · nH2O (2), where L and L′ are isonicotinic acid and nicotinic acid, respectively, have been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffractions. Both complexes are characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that complex 1 displays emissions in violet, blue and yellow regions, and the violet emission is stronger than the blue and yellow ones. Complex 2 displays emissions in orange and red regions, and the emission are attributed to the characteristic emissions of 5D0 → 7FJ (J = 0, 1, 2, 3, 4) of Eu3+ ions. Optical absorption spectra reveal the presence of an optical gap of 3.31 and 3.86 eV for 1 and 2, respectively. The magnetic properties show that complex 1 exhibits antiferromagnetic-like interactions.

Assembly of isonicotinic acid ligand (HL) with metal halide, five new hybrid complexes [CdI2(C5H4NCOOH)(C5H4NHCOO)] · H2O (1), Nan[ZnCl2(C5H4NCOO)]n · 2nH2O (2), [CdX(C5H4NCOO)]n (X = Br (3), I (4)) and [Cd3Cl2(OH)2(C5H4NCOO)2]n (5) were obtained, which display a variety of structural motifs, ranging from zero-dimensional to complicated three-dimensional networks. Complex 1 possesses an isolated unit MX2 that is further connected into 3D networks through hydrogen bonding and π–π stacking interactions. Complex 2 is characterized by an infinite one-dimensional chain of zinc atoms bridged by L− ligands. While complexes 3 and 4 possess X-bridging ∞ 1 [ CdX 2 / 2 ] inorganic chains connected by L− ligands to form a 2D hybrid network structure. In the case of 5, the cadmium(II) cation is bridged by μ3-Cl atom and μ3-OH− group to form a 2-D ∞ 2 [ Cd 6 / 2 Cl 6 / 3 ( μ 3 - OH ) 2 ] inorganic layer which is further extended into 3-D framework by bridging L− ligand via Cd–N and Cd–O bonds. The optical properties of 1, 4, and 5 in the solid state are investigated at room temperature and time-dependent DFT (TDDFT) calculation using the B3LYP functional has been performed on 1. The result indicated that the emission band of 1 is attributed to an admixture of MLCT (metal-to-ligand charge–transfer) and LLCT (ligand-to-ligand charge-transfer).

Salts of the new complexes [PW11O39{Rh2(O2CR)2}]5−; R = Prn (1), CH2Cl (2), CH2OH (3), o-C6H4OH (4), p-C6H4OH (5), and [XW11O39{Rh2(p-O2CC6H4OH)2}]6−; X = Si (6), Ge (7) have been prepared in good yield and characterized by elemental analysis, multinuclear NMR spectroscopy, and structural crystallography of the cesium salts of anions 1 and 5 with chloride ions in axial positions of the dirhodium moiety. The incorporation of the dirhodium group into the Keggin structure significantly increases the hydrolytic kinetic stability of the polyoxotungstates at pH 7–8.5, a result that has implications for the use of such complexes for imaging and for phase determination in structural studies of large biomolecules. Based on NMR studies, the axial sites of the dirhodium moiety of the polytungstate anions are accessible to ligation by molecules such as cysteine, methionine, and isonicotinic acid.

Uranyl complexes of two Schiff bases, semicarbazone and hydrazone containing OON donor atoms have been synthesized and characterized on the basis of NMR, IR and electronic spectral studies, conductance, magnetic susceptibility and thermogravimetric data. The 1H NMR spectrum of the semicarbazone complex shows low field signals due to OH, NH and ---CH=N groups at 10.23, 9.31 and 8.17 ppm, respectively. The aromatic protons appear in the range 7.74–7.40 ppm. On complexation with U(VI) the signals due to OH and NH disappear evidently due to their participation in coordination. The coordination number of the o-vanillin semicarbazone (oVSC) complex is 6 whereas, that of the o-vanillin isonicotinic acid hydrazone (oVINAH) complex is 8, in addition to the two oxygen atoms already bonded to U(VI) in each species. The thermograms show the presence of 3 and 2 water molecules in these complexes, respectively and the IR spectral data also support the above conclusion. Suitable structures have been assigned.

Tetrathiocyanate complexes of the type CoM(NCS)4· xL [(M = Zn(II), Cd(II) or Hg(II), L = 2, 3 and 4-cyanopyridine (2, 3 and 4-cpy), 2, 3 and 4-amino-pyridine (2, 3 and 4-spy), nicotinamide (nia), ethyl nicotinate (ent, or isonicotinic acid hydrazide′(inh) and x = 2, 4 or 6] have been prepared and characterized by elemental analysis, molar conductance, magnetic measurements, infrared and electronic spectral studies. The infrared spectral studies and molar conductance data show that the complexes of the type (CoM (NCS)4·6L [M = Zn(II) or Cd(II) and L = 2, 3 and 4-cpy, nia, ent, or inh] and CoZn(NCS)4·2(2-apy) are ionic and thiocyanate groups are bonded to zinc or cadmium through nitrogen end. The infrared spectral studies of the complexes of the type CoHg(SCN)4· xL [L = 2, 3 and 4-apy, 3-cpy, nia or ent and x = 2 or 4] show that the thiocyanate groups are bridged. In the complexes CoHg(SCN)4·4(4-cpy) and CoZn (NCS)4·2L (L = 3 and 4-apy) both bridging and terminal thiocyanates are present. The colour, magnetic moment data and electronic spectral studies show that in all the complexes cobalt is in octahedral environment except in the complexes of 2, 3 and 4-spy with CoZn (NCS)4 in which it is in tetrahedral environment.

A new trinuclear Cu(II) complex with isonicotinic acid N-oxide, [Cu3(N-inicO)4(OH)2(H2O)5·2H2O, has been prepared and its crystal structure determined by X-ray analysis. The complex crystallizes in the monoclinic space group P2/c with a = 12.051(4), b = 7.043(2), c = 19.825(6) A, β = 98.51(2)° and Z = 2. The arrangement of the three Cu atoms is triangular, with distances of 3.365(1) A between the central and terminal Cu atoms. The coppers are pentacoordinated; the coordination geometry is tetrahedral distorted square pyramidal for the terminal Cu atoms and elongated square pyramidal for the central Cu atom. Two hydroxo ligands and two of the four isonicotinato N-oxide ligands through the carboxyl group form bridges between Cu atoms. In addition to five coordinated waters, two lattice waters are present. The least-squares refinement led to a final R of 0.044.

The stability constants and forward and reverse rate constants have been determined for adduct formation reactions involving tetra-μ-acetato, tetra-μ-propionate and tetrakis-μ-methoxyacetatodirhodium(II) with the ligands pyridine, picolinic acid, niacin and isonicotinic acid. The experimentally observed stability trend is isonicotinic acid > pyridine ⋍ niacin ⪢ picolinic acid. It appears that the π bonding ability of the ligands determines the order of stability of these adducts. The variation of the stabilities of the adducts formed from different tetra-μ-carbox-ybtodlrhodium(II) complexes and a given ligand is related to an inductive effect as well as the lipophylic nature of the carboxylate side chain. The more hydropholic character of the propionate species apparently exerts a desolvating effect at the two axial positions resulting in a more rapid ligand exchange.

CuL n Cl 2 complexes are formed by interaction of nicotinic (n = 4) or isonicotinic (n = 1) acidd N-oxide and CuCl 2 solutions in ethanol-triethylorthofromate. The 1:4 CuCl 2 adduct with nicotinic acid N-oxide seems to be a dimer of the [L 3 ClCuL 2 CuClL 3 ]Cl 2 type, with both terminal and briging, exclusively NO oxygen-bonded ligand groups. This compound exhibits a subnormal ambient temperature magnetic moment (1.20 βB) and temperature-dependent paramagnetic behavior. The 1:1 CuCl 2 adduct with isonicotinic acid N-oxide is apparently polymeric ([CuLcl 2 ] x ), with the ligand functioning as tridentate, bridging, coordinating through all three (NO and COO) of its oxygens. This formulation is supported by the magnetic evidence, i.e. , normal ambient temperature μ eff of 2.06 μB, and measurable antiferromagnetic exchange at lower temperatures.

[Calcium(isonicotinamide)2(H2O)4]Cl2 (I), C12H20CaCl2N4O6: molecular weight = 427.3, triclinic, P1, a = 9.778(5), b = 8.623(4), c = 7.363(3) A, α = 115.09(3), β = 73.40(4), γ = 75.98(3)°, V = 489.3(3) A3, Z = 2, Dx = 1.450 g cm−3, F(000) = 222, λ(Mo Kα) = 0.71069 A, μ(Mo Kα) = 6.195 cm−1, 295 K, final R = 4.7%, Rw = 6.6% for 1985 observed reflections [I > 3σ(I)]. [Calcium(isonicotinate)2(H2O)4] (II), C12H16CaN2O8: molecular weight = 356.3, monoclinic, P21/a, a = 7.208(3), b = 36.368(28), c = 6.159(2) A, β = 104.74(3)°, V = 1561(1) A3, Z = 4, Dx = 1.516 g cm−3, F(000) = 744, λ(Mo Kα) = 0.71069 A, μ(Mo Kα) = 4.312 cm−1, final R = 6.4%, Rw = 8.3% for 1819 observed reflections [I > 3σ(I)]. In [calcium(isonicotinamide)2(H2O)4]Cl2, [C12H20CaCl2N4O6] (I), calcium is octahedrally coordinated to six oxygen atoms; four from water molecules and the carbonyl oxygen atoms of amide groups of two different isonicotinamide molecules. Amide and hetero-ring nitrogen atoms are unbound to calcium. Chloride atoms in the cell are hydrogen bonded to hydrogen atoms of amide groups. The seven coordinate calcium atom in calcium(isonicotinate)2(H2O)4, [C12H16CaN2O8] (II), is coordinated to four water molecule oxygen atoms, two oxygen atoms of a bidentate carboxylate group of one isonicotinate molecule and to the nitrogen atom of a second isonicotinate molecule.

Le complexe Cu(HINA) Cl cristallise dans le systeme monoclinique, groupe P2 1 /c et sa structure est affinee jusqu'a R=0,060. Coordination tetraedrique autour des atomes Cu

Wasrige Losungen von Metallsalzen und dem Ammoniumsalz des Liganden reagieren zu den neuen Verbindungen (I), die mit einem Wassergehalt von 1.5 bis 6 Mol isoliert werden.